The Manufacture of Biodiesel from the used vegetable oil
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The Manufacture of Biodiesel from the used vegetable oil By Nada E.M. ElSolh A thesis submitted to the Faculty of Engineering at Kassel and Cairo Universities for the degree of Master of Science Departments of Electrical and Mechanical Engineering Degree Program: Renewable Energy and Energy Efficiency for the Middle East North Africa Region- Cooperation between Kassel and Cairo Universities Under the supervision of Prof. Jürgen Schmid Prof. Fatma Ashour Electrical Engineering Department Faculty of Engineering Kassel University Chemical Engineering Dpartment Faculty of Engineering Cairo University Kassel, 28 Feb. 2011 i The Manufacture of Biodiesel from the used vegetable oil By Nada E.M. ElSolh A thesis submitted to the Faculty of Engineering at Kassel and Cairo Universities for the Degree of Master of Science Departments of Electrical and Mechanical Engineering Degree Program: Renewable Energy and Energy Efficiency for the Middle East North Africa Region- Cooperation between Kassel and Cairo Universities 1st examiner: Prof.-Dr. Fatma Ashour 2nd examiner: Prof.-Dr. Jürgen Schmid 3rd examiner: Prof. Hendawi Salem Kassel, 28 Feb. 2011 ii Abstract The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of biodiesel fuel has made it more attractive in recent times. Its primary advantages deal with it being one of the most renewable fuels currently available and it is also non-toxic and biodegradable. It can also be used directly in most diesel engines without requiring extensive engine modifications. However, the cost of biodiesel is the major hurdle to its commercialization in comparison to petroleum-based diesel fuel. The high cost is primarily due to the raw material, mostly neat vegetable oil. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, can affect the transesterification reaction and the biodiesel properties. The production of biodiesel from waste vegetable oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin vegetable oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. From an economic point of view; the production of biodiesel is very feedstock sensitive. Many previous reports estimated the cost of biodiesel production based on assumptions, made by their authors, regarding production volume, feedstock and chemical technology. From a waste management standpoint, producing biodiesel from used frying oil is environmentally beneficial, since it provides a cleaner way for disposing these products; meanwhile, it can yield valuable cuts in CO2 as well as significant tail-pipe pollution gains. Any fatty acid source may be used to prepare biodiesel. Thus, any animal or plant lipid should be a ready substrate for the production of biodiesel. The use of edible vegetable oils and animal fats for biodiesel production has recently been of great concern because they compete with food materials - the food versus fuel dispute (Pimentel et al., 2009; Srinivasan, 2009). There are concerns that biodiesel feedstock may compete with food supply in the long-term. Hence, the recent focus is the use of non-edible plant oil source and waste products of edible oil industry as the feedstock for biodiesel production meeting the international standards. Quality standards are prerequisites for the commercial use of any fuel product. iii This Master Thesis is about the manufacturing of biodiesel from the used vegetable oil. This study aims to define the requirements for biodiesel production by the esterification process, testing its quality by determining some parameters such as density, kinematics viscosity, high heating value, cetane number, flash point, cloud pint and pour point and comparing it to Diesel fuel, testing the engine performance, testing the emissions of biodiesel and comparing it to diesel emission, and the strategic issues to be considered to assess its feasibility, or likelihood of succeeding. This analysis is useful either when starting a new business, or identifying new opportunities for an existing business. Therefore, it will be extremely helpful for taking rational decisions about the development of a biodiesel production plant. iv Acknowledgements In the first place I want to thank God for giving me the strength to finish this Master Thesis. Three semesters passed and I had some good days and other hard ones, and whenever I was down, God gave me the hope and strength to continue this Master Thesis successfully. Words cannot express my thanks to my wonderful family for their non stopping support during the period of my study and for believing in me and in my work. Special thanks go to Prof. Dahlhaus, the coordinator of the REMENA Master Program, for being understandable and allowing me to do my defense in Kassel, that was very kind and generous of him, it’s known about him that he’s very supportive to students. I would like to thank my supervisors Prof. Fatma Ashour from Cairo University and Prof. Jürgen Schmid from Kassel University for their supervision, advice and guidance from the very early stage of my Master thesis as well as providing me great experiences through out this work. And of course many thanks to all my professors in Cairo and Kassel Universities for their non stopping support I also want to thank Prof. Schmid for arranging the practical work of my Master thesis in the University of Applied Science (HAW) in Amberg, in Germany and giving me this opportunity to work in the Mechanical Engineering department that will help me out in many ways in my future education. Special thanks to Stefanie Reil, Prof. Schmid’s PhD student, for helping from the first day I arrived to Amberg, from putting the basics for my Master Thesis until the day of submitting it, also I will not forget her wonderful team, Sabine Feldmeier for letting me work with her CHNS device and Suzanna Ritz for helping me in arranging my thesis, and of course many thanks to the other people who helped me in my thesis. I just can’t remember all the names. Many many thanks to Raphael Lechner, a PhD student, for helping me in performing all the experiments needed for my thesis in the lab, also many thanks to him for giving me much from his time whenever I have questions concerning my thesis and for reviewing all of my thesis. This paper would not have been possible without the support of the DAAD, the German Academic Exchange Service, special thanks to Mr. Heinemann and Mrs. Anke Stahl for bearing with us and answering all of our questions patiently. Also many thanks to everyone who made the REMENA Master Program a successful one. Finally, I would like to thank my colleagues in the REMENA Master Program for their support and I would like to say that it was a nice opportunity for me to meet these nice people. v Contentsts 1 Motivation..........................................................................................…….1 2 Why Biodiesel?!......................................................................................3 3 Introduction...............................................................................................6 4 An Overview..............................................................................................9 4.1 Bio Energy..................................................................................................9 4.2 Biomass energy........................................................................................10 4.3 The Carbon Cycle.....................................................................................11 4.3.1 Movement of Carbon through the atmosphere……………………..12 4.3.2 The carbon cycle and biofuels…………………………………….….13 5 Biofuels....................................................................................................14 5.1 What are Biofuels.....................................................................................14 5.2 Biofuel generation.....................................................................................19 6 Biodiesel Production..............................................................................22 6.1 What is Biodiesel......................................................................................22 6.2 History of Biodiesel...................................................................................23 6.3 The advantages of using vegetable oils as fuels:....................................24 6.4 Characteristics of oils or fats affecting their suitability for use as biodiesel………………………………………………………………….….………..25 6.5 Review of biodiesel feedstock……………………………………………….27 6.6 Vegetable oils as diesel fuels...................................................................28 6.7 Transesterification of vegetable oil:..........................................................29 6.8 Biodiesel production from used cooking oil..............................................31 7 Biodiesel as an engine fuel...................................................................34 7.1 Overview…………………………………………………………………..……34 7.2 Technical characteristics of biodiesel as a transportation fuel.................34 7.3 Engine performance characteristics of biodiesel......................................37 7.4 Engine emissions from biodiesel..............................................................38 7.5 Environmental Benefits of Biodiesel Fuel.................................................39 7.6 Environmental benefits in comparison to petroleum based fuels include 41 7.7 Some challenges for using biodiesel fuel.................................................42 8 Biodiesel Economy................................................................................43 8.1 Overview……………………………………………………………………….43 vi 8.2 Biodiesel production economic balance……………………………….…...45 8.2.1 Feedstock prices…………………………………………………….....45 8.2.2 Biodiesel production costs…………………………………………….45 8.2.3 Taxation of energy products…………………………………………..47 9 9.1 Experimental Part....................................................................………….48 The production of Biodiesel from rapeseed oil experiment.……...............49 9.1.1 Pressing of Rapeseed oil....……………………………………………49 9.1.2 The determination of free fatty acid...…………………………………50 9.1.3 Transestrification: ……………………………………………………….51 9.1.4 Thin layer chromatography……………………………………….…....51 9.2 Fuel analytics…………………………………………………………………..53 9.2.1 Introduction. ………………………………………………………….….53 9.2.2 Technical Details and Standards of diesel and biodiesel……….…..53 9.2.3 Kinematic Viscosity measurement: The Ubbelohde viscometer…...55 9.2.4 Density Measurement: Hydrometer and Pycnometer……………….57 9.2.4.1 Hydrometer………………………………………......................57 9.2.4.2 Pycnometer………………………………………………….......58 9.2.5 Heating value Measurement: the Bomb Calorimeter……………….59 9.2.6 Measuring the oxidation stability……………………………………....61 9.3 CHNS Elemental Analyzer (EA)………………………………………………..65 9.4 Experimental and Standard results of density, viscosity, heating value and oxidation stability for rapeseed oil, two types of biodiesel and diesel fuel……………………………………………………………………………………...69 9.5 Discussion of results……………………………………………………………..75 9.6 The Emission testing experiment for rapeseed oil, low sulfur diesel fuel and biodiesel (from gas station)…………………………………………………………..79 9.6.1 Equipment used………………………………………………………..79 9.6.2 Procedure of the emission testing experiment…………………........83 9.6.3 Tabulated Results of the emission testing experiment………….........85 9.6.4 Graphical Results: Comparing the emissions of rapeseed oil, diesel and biodiesel………………………………………………………………………………...88 9.6.5 Discussion of Results: Comparing between the results of the emission testing experiment of diesel and biodiesel fuels…………………………………....92 vii 10 Summary……………………………………………………………….……….....94 11 Conclusion and Recommendations…………………………………………..97 Bibliography………………………………………………………………………...100 List of Figures..................................................................................................103 List of tables.....................................................................................................105 Appendix A…………………………………………………………………..…..…..107 Appendix B……………………………………………………………………..……123 viii Abbreviations Symbol Meaning ASTM American Society for Testing and Materials Bxx The level of blending biodiesel with petroleum diesel B2 2% biodiesel and 98% petroleum diesel B5 5% biodiesel and 95% petroleum diesel B20 20%biodiesel and 80% petroleum diesel B100 Pure biodiesel BD Bio Diesel Bsfc brake-specific fuel consumption Btu/lb British thermal unit per pound CH4 Methane CI Compression Ignition CO Carbon monoxide CO2 Carbon dioxide D2 Diesel fuel Derv Diesel engine road vehicle DI Direct injection DME Dimethyl ether (CH3OCH3 ) DMF Dimethylfuran ((CH3)2C4H2O) EEA European Environment Agency EPA Environmental Protection Agency EN14214 European standards for biodiesel EU European Union FAE Fatty acid esters FAME Fatty acid methyl ester ix FFAs Free fatty acids FID Flame ionization detector H2 Hydrogen IEA International Energy Agency KW Kilo watt LHV Lower heating value LPG Liquefied petroleum gas CNG Compressed natural gas MTBE Methyl tertiary-butyl ether NDIR Non dispersive infrared sensor NO Nitric oxide NOx Nitrogen Oxide N2O Nitrous oxide O2 Oxygen OECD Organization for Economic Co-operation and Development POME Palm oil methyl esters PM Particular matter Pr Rapeseed price REN21 Renewable Energy Policy Network for the 21st Century R&D Research & Development Rpm Revolutions per minute SME Soya bean oil methyl ester SO2 Sulfur dioxide THC Total Hydrocarbon Analyzer UV Ultra Violet VIS Visual light spectrometer x Chapter 1 Motivation Several billions of gallons of waste vegetable oil are produced every year around the world, mainly from industrial deep fat fryers found in potato processing plants, factories manufacturing foods, and restaurants. Some of this wastage is already being re-used by other industries, such as in animal feed and cosmetics, but the amount that is still being wasted and ending up in land-fill sites is alarming. Therefore it makes commercial and environmental sense to re-use this oil for making biodiesel. Making biodiesel from waste vegetable oil (WVO) is much the same as when using straight vegetable oil, except that the oil will need filtering first to remove debris, and because it has been used and most likely reheated several times, more fatty acids will be present so we need to determine how much more sodium hydroxide (or potassium hydroxide) to add to neutralize these acids. This is called a titration test.(1) Vegetable Oil is commonly available everywhere and there at every home and most households dump the waste oil rather than utilizing that. Making biodiesel from waste vegetable oil is one of the most productive ways to utilize waste vegetable oil. Moreover, day by day fuel is getting expensive and inflation is hitting new highs across every country across the world. Everyone has started looking for cheap substitutes for everything in the world. Making Biodiesel from waste vegetable oil is an upcoming way of preserving energy and meeting our own requirements without depending on anyone. Biodiesel is a diesel fuel that is made by reacting vegetable oil (cooking oil) with other common chemicals that are easily available in the market. Biodiesel may be used in any diesel automotive engine in its pure form or blended with petroleum-based diesel, so need not worry about anything. No modifications are required, and the result is a less-expensive, renewable, clean-burning fuel.(2) Biodiesel is a product of great interest for its environmental characteristics. It is biodegradable and it’s renewable. It has the advantages of dramatically reduced sulfate and hydrocarbon emissions and reduces particulate matter. It is nontoxic and does not damage water quality. Biodiesel is a fuel that can be made from pure or waste vegetable oils such as soya and rape seed (canola) oil, mixed with methane and a small amount of lye. It runs a diesel engine just as petroleum-based diesel would. (3) 1 Additionally to its environmental characteristics, It is evident, that there is a latent demand of this product because of the recent rises in the price of oil, and the realization that fossil fuels will eventually run out, not to mention the damage burning them does to our planet, this resulted in renewed interest in fuel made from plant oils or biodiesel. That is why it is necessary to study the potential of biodiesel, as well as to study its feasibility, if it will be used as a viable alternative fuel in the future. 2 Chapter 2 Why Biodiesel?! It's Economical Biodiesel can be produced by individuals on a small scale relatively inexpensively when compared to Petrodiesel. Figures range anywhere from $0.40 a gallon to about $1.25 a gallon depending on the cost of materials required to make it. With prices that low, most people are able to save hundreds of dollars on their fuel bills. In some cases it even goes into the thousands of dollars. With savings like that, most people are able to recoup their initial investment on the equipment needed to make biodiesel within a matter of months. It's Renewable Biodiesel has been touted far and wide for its renewable properties. Instead of making a fuel from a finite resource such as crude oil, Biodiesel can be produced from renewable resources such as organic oils, fats, and tallows. This means that it can be made from things that can be regrown, reproduced, and reused. So, if you need more, you can just grow another crop of seeds for the oil. It's Good For the Environment When Biodiesel is used to power diesel engines, the emissions at the tailpipe are significantly reduced. Studies by the US National Renewable Energy Lab indicate drops in several key areas’ that help the environment. Carbon Dioxide, Hydrocarbons, and Particulate Matter (the black smoke from diesels) all are significantly reduced when Biodiesel is used. When used in older diesel engines such as indirect combustion diesels, the results are astounding. There was a reduction in the tailpipe emissions of nearly 90%. It also has a positive energy balance. 3 It supports farmers When Biodiesel is made from organic oils such as Canola, Soy, Peanut, or other domestically grown seed crops, it helps the farming community out. Because the oil used to make Biodiesel is "domestically grown", it keeps the money flowing to those that "grow" the feedstock. This continues to help out the renewable aspect of Biodiesel because this means more seed crops can be grown by local farmers. It reduces dependency on Crude Oil When Biodiesel is used in place of petrodiesel, it reduces the amount of crude oil used up. This means that it helps to reduce our dependence on a limited resource and increases our use of renewable resources. We think that's a great step toward reducing our dependence on a fuel that may not be around forever. It's enjoyable to make We think that making Biodiesel is one of the funniest things in the world to do. With a little practice and know-how it can easily be made and is extremely simple to do. We've found it to be an incredibly fulfilling experience. There's just something to be said for being able to make your own fuel and drive past a gas station and wave instead of pulling up for a fill-up. Words just don't describe the incredible feeling we get each time we make a batch. It's good for the engine Biodiesel, unlike Petrodiesel, has a much higher "lubricity" to it. This means that it's essentially "slipperier" than normal diesel fuel. With the added "lubricity" of Biodiesel, engines have been shown to experience less wear and tear when used on a regular basis. Also, because Biodiesel is less polluting, it means that it's easier on the engine. US Government Studies have shown that in some cases large fleets using Biodiesel have been able to go longer between oil changes because the oil stay's cleaner when Biodiesel is used. It's the perfect alternative fuel When compared to several other Alternative Fuels available, Biodiesel comes out way ahead. Most alternative fuels require changes to a vehicle to be used. Natural Gas & Propane require special tanks to be installed and changes to the fuel injection system must be made as well. Ethanol also requires specialized changes to the fuel injection system. Electricity requires a completely different engine. In most cases, once a vehicle undergoes 4 the conversion necessary to run the alternative fuel, there's no going back. You either run the alternative fuel or you don't run the vehicle. (4) 5 Chapter 3 Introduction During the last century, the consumption of energy has increased a lot due to the change in the life style and the significant growth of population. This increase of energy demand has been supplied by the use of fossil resources, which caused the crises of the fossil fuel depletion, the increase in its price and the serious environmental impacts as global warming, acidification, deforestation, ozone depletion, Eutrophication and photochemical smog. As fossil fuels are limited sources of energy, this increasing demand for energy has led to a search for alternative sources of energy that would be economically efficient, socially equitable, and environmentally sound. Two of the main contributors of this increase of energy demand have been the transportation and the basic industry sectors, being the largest energy consumers. The transport sector is a major consumer of petroleum fuels such as diesel, gasoline, liquefied petroleum gas(LPG) and compressed natural gas (CNG)’ (Demirbas, 2006). Demand for transport fuels has risen significantly during the past few decades. (IEA, 2008). The demand for transport fuel has been increasing and expectations are that this trend will stay unchanged for the coming decades. In fact, with a worldwide increasing number of vehicles and a rising demand of emerging economies, demand will probably rise even harder. Transport fuel demand is traditionally satisfied by fossil fuel demand. However, resources of these fuels are running out, prices of fossil fuels are expected to rise and the combustion of fossil fuels has detrimental effects on the climate. The expected scarcity of petroleum supplies and the negative environmental consequences of fossil fuels have spurred the search for renewable transportation biofuels’ (Hill, Nelson, Tilman, Polasky& Tiffany, 2006). Biofuels appear to be a solution to substitute fossil fuels because, resources for it will not run out (as fresh supplies can be re grown), they are becoming cost wise competitive with fossil fuels, they appear to be more environmental friendly and they are rather accessible to distribute and use as applicable infrastructure and technologies exists and are readily available. Forecasts are that transport on a global scale will increase demand for conventional fuels with up to a maximum annual growth of 1.3% up to 2030. This would result in a daily demand of around 18.4 billion litres (up from around 13.4 billion litres per day in 2005) (The Royal Society, 2008). 6 Conventional fuel, however, are predicted to become scarcely (The Royal Society, 2008) as ‘petroleum reserves are limited’ (Demirbas, 2006), for this reason these fuels are set to become increasingly costly in the coming decades. Renewable fuels, made from biomass, ‘have enormous potential and can meet many times the present world energy demand’ (IEA, 2008). ‘Biomass can be used for energy in several ways; one of these is the conversion into liquid or gaseous fuels such as ethanol and bio-diesel for use in mobile source combustion’ (Marshall, 2007). In fact ‘global demand for liquid biofuels more than tripled between 2000 and 2007. And future targets and investment plans suggest strong growth will continue in near future’ (IEA, 2008). The potential of biofuels appear to be enormous from an economical, political and environmental perspective. Speaking in terms of advantages, much heard is that they, as an alternative fuel, could solve several issues as the increasing energy prices worldwide, the increasing need of energy imports, the negative environmental consequences of fossil fuel combustion and the security of national energy supply for many countries. Biofuels appear to be more environment friendly in comparison to fossil fuels considering the emission of greenhouse gasses when consumed. Examples of those gasses are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Those gasses pose risks as they tend to warm the earth’s surface’ (Randelli, 2007). The energy content of biofuels differs from conventional fuels. Total energy output per liter of biofuel is determined by the feedstock used, region where the feedstock is grown and production techniques applied. Randelli (2007) provides, for example, energy contents of biodiesel and bio ethanol. According to Randelli, ‘Biodiesel has an energy ratio compared to diesel of about 1.1 to 1, which means that its energy contents are 87% of those of diesel. Bio ethanol has an energy ratio compared to gasoline of 1.42 (67% of gasoline)’.The amount that is similar to the amount of energy content of one litres gasoline is referred to as gasoline equivalent. Biodiesel production is a very modern and technological area for researchers as an alternative fuel for diesel engines because of the increase in the petroleum price, its renewability and the environmental advantages. Biodiesel can be produced from renewable sources such as vegetable oil, animal fat and used cooking oil. Currently, the cost of biodiesel is high as compared to conventional diesel oil because most of the biodiesel is produced from pure vegetable oil. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. 7 However, the cost of biodiesel can be reduced by using low cost feedstock such as animal fat and used cooking oil. It is estimated that the cost of biodiesel is approximately 1.5 times higher than that of diesel fuel due to the use of food grade oil for biodiesel production. The term “waste vegetable oil” (WVO) refers to vegetable oil which has been used in food production and which is no longer viable for its intended use. Waste vegetable oil arises from many different sources, including domestic, commercial and industrial. Waste vegetable oil is a potentially problematic waste stream which requires to be properly managed. The disposal of waste vegetable oil can be problematic when disposed, incorrectly, down kitchen sinks, where it can quickly cause blockages of sewer pipes when the oil solidifies. Properties of degraded used frying oil after it gets into sewage system are conductive to corrosion of metal and concrete elements. It also affects installations in waste water treatment plants. Thus, it adds to the cost of treating effluent or pollutes waterways. The use of used cooking oil as feedstock reduces biodiesel production cost by about 60– 70% because the feedstock cost constitutes approximately 70–95% of the overall biodiesel production cost. It is reported that the prices of biodiesel will be reduced approximately to the half with the use of low cost feedstock [Kemp, 2006; Radich, 2006; Anh et al., 2008]. Moreover used cooking oils can be a workable feedstock for biodiesel production as they are easily available. The use of non-edible plant oils when compared with edible oils is very significant because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The land use for growing oilseeds as feedstocks for the biodiesel production competes with the use of land for food production. (5) 8 Chapter 4 An Overview of Bioenergy, Biomass and the Carbon Cycle 4.1 Bio Energy Bioenergy is one of the so-called renewable energies. It’s is the energy that is contained in living or recently living biological organisms. (6) Bio-energy is obtained from organic matter, either directly from plants or indirectly from industrial, commercial, domestic or agricultural products and waste. The use of bioenergy is generally classed as a carbon-neutral process because the carbon dioxide released during the generation of energy is balanced by that absorbed by plants during their growth. (7) The term bio-energy really covers two areas: bio-fuel which is the transformation of plant materials into liquid fuel, and bio-mass, where solid plant materials are burnt in a power plant and this process creates energy, which can then be for immediate use or stored. (8) Advanced and efficient conversion technologies now allow the extraction of biofuels besides the traditional use of bioenergy; ‘Modern bioenergy’ comprises biofuels for transport, and processed biomass for heat and electricity production. 9 4.2 Biomass Energy Biomass is the name given to all the earth’s living matter. It is a general term for material derived from growing plants or from animal manure (which is effectively a processed form of plant material). It is a rather simple term for all organic material that stems from plants (including algae), trees and crops. Biomass energy is derived from plant and animal material, such as wood from natural forests, waste from agricultural and forestry processes and industrial, human or animal wastes. Plants absorb solar energy, using it to drive the process of photosynthesis, which enables them to live. The energy in biomass from plant matter originally comes from solar energy through the process known as photosynthesis. The energy, which is stored in plants and animals (that eat plants or other animals), or in the wastes that they produce, is called biomass energy. This energy can be recovered by burning biomass as a fuel. During combustion, biomass releases heat and carbon dioxide that was absorbed while the plant was growing. Essentially, the use of biomass is the reversal of photosynthesis. Therefore, the energy obtained from biomass is a form of renewable energy and, in principle, utilizing this energy does not add carbon dioxide to the environment, in contrast to fossil fuels. Biomass can be used directly (e.g. burning wood for heating and cooking) or indirectly by converting it into a liquid or gaseous fuel (e.g. alcohol from sugar crops or biogas from animal waste). Biomass is used in a similar way to fossil fuels, by burning it at a constant rate in a boiler furnace to heat water and produce steam. Liquid biofuels, such as wheat, sugar, root, rapeseed and sunflower oil, are currently being used in some member states of the European Union. Biomass provides a clean, renewable energy source that could dramatically improve our environment, economy and energy security. Biomass energy generates far less air emissions than fossil fuels, reduces the amount of waste sent to landfills and decreases our reliance on foreign oil. Biomass energy also creates thousands of jobs and helps revitalize rural communities. (9) 10 4.3 The Carbon Cycle Carbon is an element that is part of oceans, air, rocks, soil and all living things, Carbon doesn’t stay in one place but it is always on the move. Carbon moves naturally to and from various parts of the Earth. This is called the carbon cycle. Today, however, scientists have found that more carbon is moving into the atmosphere from other parts of the Earth when fossil fuels, like coal and oil, are burned. Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But humans have burned so much fuel that there is about 30% more carbon dioxide in the air today than there was about 150 years ago. The atmosphere has not held this much carbon for at least 420,000 years according to data from ice cores. More greenhouse gases such as carbon dioxide in our atmosphere are causing our planet to become warmer. (10) Figure 4.3.1: The Carbon Cycle; the movement of Carbon dioxide through the atmosphere. ( 11 http://www.windows2universe.org) 11 4.3.1 Movement of Carbon through the atmosphere - Carbon moves from the atmosphere to plants. In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2). With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food from carbon. - Carbon moves from plants to animals. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too. -Carbon moves from plants and animals to the ground. When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. Some becomes buried miles underground and will become fossil fuels in millions and millions of years. -Carbon moves from living things to the atmosphere. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration. -Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. That’s the weight of 100 million adult African elephants! Of the huge amount of carbon that is released from fuels, 3.3 billion tons enters the atmosphere and most of the rest becomes dissolved in seawater. - Carbon moves from the atmosphere to the oceans. 12 The oceans, and other bodies of water, soak up some carbon from the atmosphere.12 4.3.2 The carbon cycle and biofuels CO2 is part of the Earth’s natural carbon cycle, which circulates carbon through the atmosphere, plants, animals, oceans, soil, and rocks. This cycle maintains a life-sustaining and delicate natural balance between storing, releasing, and recycling carbon. By using biofuels such as bioethanol and biodiesel for transportation, we can help restore the natural balance of CO2 in the atmosphere. Besides displacing fossil fuels, the feedstocks used to make biofuels require CO2 to grow, and they absorb what they need from the atmosphere. Thus, much or all of the CO2 released when biomass is converted into a biofuel and burned in automobile engines is recaptured when new biomass is grown to produce more biofuels. (13) Figure 4.3.2: Biofuels and the carbon cycle ( 12 http://www.energyfuturecoalition.org/biofuels) 13 Chapter 5 Biofuels 5.1 What are Biofuels Biofuels are energy carriers that store the energy derived from biomass, commonly produced from plants, animals and micro-organisms and organic wastes. Biofuels may be solid, liquid or gaseous and include all kinds of biomass and derived products used for energetic purposes. Biofuels are renewable energy sources, meaning that fresh supplies can be regrown. They are a possible substitute product for fossil fuels. Compared with the latter product there are some advantages to subscribe to biofuels. Advantages and benefits of biofuels, however, depend on the categorization of the specific biofuel, type of feedstock used and technology applied to produce it. Table 5.1: Major benefits of Biofuels ( 14 Political, economic and environmental impacts of biofuels: A review Ayhan Demirbas * Sila Science, Trabzon, Turkey) 14 There are two global liquid transportation biofuels that might replace gasoline and diesel fuel; these are ethanol and biodiesel, respectively. Transport is one of the main energy consuming sectors. It is assumed that biodiesel is used as a petroleum diesel replacement and that ethanol is used as a gasoline replacement. Figure 5.1.1 shows the sources of the main liquid biofuels for automobiles. Figure 1.1.1: Sources of main liquid biofuels for automobiles 15 ( Biodiesel, a realistic fuel alternative for diesel engines- springer-2008.pdf) Bioethanol, followed by biodiesel are the most produced types of biofuel. Figure 5.1.2 shows the world’s top ethanol and biodiesel producers in 2008. The United States (US) and Brazil are currently the leading ethanol producers and the expectations are that this will at least until 2018 remain so. The European Union (EU) is the world’s leading producer of biodiesel. 15 Figure 5.1.2: The world’s top ethanol and biodiesel producers in 2008 (REN21, 2009) Biofuels for transportation primarily driven by government policies, world ethanol production for transport fuel tripled between 2000 and 2007 from 17 billion to more than 52billion litres, while biodiesel expanded eleven-fold from less than 1 billion to almost 11 billion litres (Fig.3). These fuels together provided 1.8% of the world’s transport fuel by energy value (36 Mtoe out of a total of 2007 Mtoe) (OECD 2008). In Europe there has been a continuing increase in the use of biofuels in road transport over the past decade from 0.1% in 1997 to 2.6% in 2007 (EEA 2008 a,b). Figure 5.1.2: Global ethanol and biodiesel production 2000-2008 with projection to 2015 16 There are a variety of biofuels potentially available, but the main biofuels being considered globally are biodiesel and bioethanol. Bio-ethanol can be produced from a number of crops including sugarcane, corn (maze), wheat and sugar beet. Biodiesel is the fuel that can be produced from straight vegetable oils, edible and non-edible, recycled waste vegetable oils, and animal fat. The main producing countries for transport biofuels are the USA, Brazil, and the EU. Production in the United States was mostly ethanol from corn, in Brazil was ethanol from sugar cane, and in the European Union was mostly biodiesel from rapeseed. Figure 5.1.3: Biodiesel Production Cycle 16 ( http://www.window.state.tx.us/specialrpt/energy/renewable/biodiesel.php) Figure 5.1.4 shows the Biodiesel production Cycle, solar energy and carbon dioxide along with other inputs are used to grow crops that are in turn harvested and processed. As an example, soybeans are crushed to produce oil that is the basic material to be turned into biodiesel. The production process forces the vegetable oil to react with a catalyst to produce fatty acid esters, the chemical name for biodiesel. The fuel is then used in existing vehicles which also produce carbon dioxide. 17 Figure 4.1.5: Ethanol Production Cycle 17 ( http://www.window.state.tx.us/specialrpt/energy/renewable/ethanol.php) Figure 5.1.5 shows Ethanol Production Cycle, Ethanol supporters say that its production and consumption are carbon-neutral. Crops like corn are finely ground and separated into their component sugars. The sugars are distilled to make ethanol, which can be used as an alternative fuel, which releases carbon dioxide that is reabsorbed by the original crops. 18 5.2 Biofuel generation Biofuels for transport are commonly addressed according to their current or future availability as first, second or third generation biofuels (OECD/ IEA 2008). Second and third generation biofuels are also called “advanced” biofuels. First-generation biofuels are commercially produced using conventional technology. The basic feedstocks are seeds, grains, or whole plants from crops such as corn, sugar cane, rapeseed, wheat, sunflower seeds or oil palm. These plants were originally selected as food or fodder and most are still mainly used to feed people. The most common first-generation biofuels are bioethanol (currently over 80% of liquid biofuels production by energy content), followed by biodiesel, vegetable oil, and biogas. Second-generation biofuels can be produced from a variety of non-food sources. These include waste biomass, the stalks of wheat, corn stover, wood, and special energy or biomass crops (e.g. Miscanthus). Second-generation biofuels use biomass to liquid (BtL) technology, by thermo chemical conversion (mainly to produce biodiesel) or fermentation (e.g. to produce cellulosic ethanol).Many second-generation biofuels are under development such as biohydrogen, biomethanol, DMF, Bio-DME, Fischer-Tropsch diesel, biohydrogen diesel, and mixed alcohols. Third-generation biofuel: Algae fuel, also called oilgae, is a biofuel from algae and addressed as a third-generation biofuel (OECD/IEA 2008). Algae are feedstocks from aquatic cultivation for production of triglycerides (from algal oil) to produce biodiesel. The processing technology is basically the same as for biodiesel from second-generation feedstocks. Other third -generation biofuels include alcohols like bio-propanol or bio-butanol, which due to lack of production experience are usually not considered to be relevant as fuels on the market before 2050 (OECD/IEA 2008), though increased investment could accelerate their development. The same feedstocks as for first-generation ethanol can be used, but using more sophisticated technology. Propanol can be derived from chemical processing such as dehydration followed by hydrogenation. As a transport fuel, butanol has properties closer to gasoline than bioethanol. 19 Table 5.2: An Overview of the product biofuel, per generation type ( 18 Own elaboration, primarily based on http://news.mongabay.com) Current use of biofuels for transport on the global scale is dominated by bioethanol and biodiesel, whereas the use of other biofuels for transport like biogas and pure plant oil seem to be restricted to local and regional pilot cases, and second-generation biofuels are still in the development stage. Commercial investment in advanced (second-generation) biofuel plants is beginning in Canada, Germany, Finland, Japan, the Netherlands, Sweden, and the United States (REN21 2008; EEA 2008a,b). 20 Figure 5.2: The World’s and EU’s biofuel consumption 21 Chapter 6 Biodiesel production 6.1 What is Biodiesel In the most general sense, biodiesel refers to any diesel fuel substitute derived from renewable biomass. More specifically, biodiesel is defined as an oxygenated, sulfur-free, biodegradable, non-toxic, and eco-friendly alternative diesel oil. Chemically, it can be defined as a fuel composed of mono-alkyl esters of long chain fatty acids derived from renewable sources, such as vegetable oil, animal fat, and used cooking oil designated as B100, and also it must meet the special requirements such as the ASTM and the European standards. For these to be considered as viable transportation fuels, they must meet stringent quality standards. One popular process for producing biodiesel is transesterification. Biodiesel is made from a variety of natural oils such as soybeans, rapeseeds, coconuts, and even recycled cooking oil. Rapeseed oil dominates the growing biodiesel industry in Europe. In the United States, biodiesel is made from soybean oil because more soybean oil is produced in the United States than all other sources of fats and oil combined. (19) The injection and atomization characteristics of the vegetable oils are significantly different than those of petroleum derived diesel fuels, mainly as the result of their high viscosities. Modern diesel engines have fuel-injection system that is sensitive to viscosity change. One way to avoid these problems is to reduce fuel viscosity of vegetable oil in order to improve its performance. The conversion of vegetable oils into biodiesel is an effective way to overcome all the problems associated with the vegetable oils. Dilution, micro emulsification, pyrolysis, and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Transesterification is the most common method and leads to mono alkyl esters of vegetable oils and fats, now called biodiesel when used for fuel purposes. The methyl ester produced by transesterification of vegetable oil has a high cetane number, low viscosity and improved heating value compared to those of pure vegetable oil which results in shorter ignition delay and longer combustion duration and hence low particulate emissions. 22 6.2 History of Biodiesel Dr. Rudolf Diesel invented the diesel engine to run on a host of fuels including coal dust suspended in water, heavy mineral oil, and, vegetable oils. Dr. Diesel’s first engine experiments were catastrophic failures, but by the time he showed his engine at the World Exhibition in Paris in 1900, his engine was running on 100% peanut oil. Dr. Diesel (Fig. 14) was visionary. In 1911 he stated ‘‘the diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture of the countries, which use it’’. In 1912, Diesel said,’ the use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time’’. Since Dr. Diesel’s untimely death in 1913, his engine has been modified to run on the polluting petroleum fuel, now known as ‘‘diesel’’. Nevertheless, his ideas on agriculture and his invention provided the foundation for a society fueled with clean, renewable, locally grown fuel. In the 1930s and 1940s, vegetable oils were used as diesel substitutes from time to time, but usually only in emergency situations. Recently, because of increase in crude oil prices, limited resources of fossil oil and environmental concerns, there has been a renewed focus on vegetable oils and animal fats to make biodiesel. Continued and increasing use of petroleum will intensify local air pollution and magnify the global warming problems caused by carbon dioxide. In a particular case, such as the emission of pollutants in the closed environment of underground mines, biodiesel has the potential to reduce the level of pollutants and the level of potential for probable carcinogens. Figure 6.2: Dr. Rudolf Diesel 23 6.2 The advantages of using vegetable oils as fuels Vegetable oils are liquid fuels from renewable sources; they do not over-burden the environment with emissions. Vegetable oils have potential for making marginal land productive by their property of nitrogen fixation in the soil. Their production requires lesser energy input in production. They have higher energy content than other energy crops like alcohol. They have 90% of the heat content of diesel and they have a favorable output/input ratio of about 2–4:1 for un-irrigated crop production. The current prices of vegetable oils in world are nearly competitive with petroleum fuel price. Vegetable oil combustion has cleaner emission spectra and simpler processing technology. But these are not economically feasible yet and need further R&D work for development of on farm processing technology. Due to the rapid decline in crude oil reserves, the use of vegetable oils as diesel fuels is again promoted in many countries. Depending up on climate and soil conditions, different nations are looking into different vegetable oils for diesel fuels. For example, soybean oil in the USA, rapeseed and sunflower oils in Europe, palm oil in Southeast Asia(mainly Malaysia and Indonesia), and coconut oil in Philippines are being considered as substitutes for mineral diesel. An acceptable alternative fuel for engine has to fulfill the environmental and energy security needs without sacrificing operating performance. Vegetable oils can be successfully used in CI engine through engine modifications and fuel modifications because Vegetable oil in its raw form cannot be used in engines. It has to be converted to a more engine-friendly fuel called biodiesel. Biodiesel has comparable energy density, cetane number, heat of vaporization, and stoichiometric air/fuel ratio with mineral diesel. The large molecular size of the component triglycerides result in the oil having higher viscosity compared with that of mineral diesel. Viscosity affects the handling of the fuels by pump and injector system, and the shape of fuel spray. 24 6.3 Characteristics of oils or fats affecting their suitability for use as biodiesel • Calorific Value, Heat of Combustion – Heating Value or Heat of Combustion, is the amount of heating energy released by the combustion of a unit value of fuels. One of the most important determinants of heating value is moisture content. Air-dried biomass typically has about 15-20% moisture, whereas the moisture content for oven-dried biomass is negligible. Moisture content in coals varies in the range 2-30%. However, the bulk density of most biomass feedstocks is generally low, even after densification – between about 10 and 40% of the bulk density of most fossil fuels. Liquid biofuels however have bulk densities comparable to those for fossil fuels. • Melt Point or Pour Point - Melt or pour point refers to the temperature at which the oil in solid form starts to melt or pour. In cases where the temperatures fall below the melt point, the entire fuel system including all fuel lines and fuel tank will need to be heated. • Cloud Point - The temperature at which an oil starts to solidify is known as the cloud point. While operating an engine at temperatures below oil’s cloud point, heating will be necessary in order to avoid waxing of the fuel. • Flash Point - The flash point temperature of a fuel is the minimum temperature at which the fuel will ignite (flash) on application of an ignition source. Flash point varies inversely with the fuel’s volatility. Minimum flash point temperatures are required for proper safety and handling of diesel fuel. • Iodine Value - Iodine Value (IV) is a value of the amount of iodine, measured in grams, absorbed by 100 grams of a given oil. Iodine value (or Iodine number) is commonly used as a measure of the chemical stability properties of different biodiesel fuels against such oxidation as described above. The Iodine value is determined by measuring the number of double bonds in the mixture of fatty acid chains in the fuel by introducing iodine into 100 grams of the sample under test and 25 measuring how many grams of that iodine are absorbed. Iodine absorption occurs at double bond positions - thus a higher IV number indicates a higher quantity of double bonds in the sample, greater potential to polymerize and hence lesser stability. • Viscosity – Viscosity refers to the thickness of the oil, and is determined by measuring the amount of time taken for a given measure of oil to pass through an orifice of a specified size. Viscosity affects injector lubrication and fuel atomization. Fuels with low viscosity may not provide sufficient lubrication for the precision fit of fuel injection pumps, resulting in leakage or increased wear. Fuel atomization is also affected by fuel viscosity. Diesel fuels with high viscosity tend to form larger droplets on injection which can cause poor combustion, increased exhaust smoke and emissions. • Cetane Number - Is a relative measure of the interval between the beginning of injection and auto ignition of the fuel. The higher the cetane number, the shorter the delay interval and the greater its combustibility. Fuels with low Cetane Numbers will result in difficult starting, noise and exhaust smoke. In general, diesel engines will operate better on fuels with Cetane Numbers above 50. Cetane tests provide information on the ignition quality of a diesel fuel. Research using cetane tests will provide information on potential tailoring of vegetable oil-derived compounds and additives to enhance their fuel properties. • Density – Is the weight per unit volume. Oils that are denser contain more energy. For example, petrol and diesel fuels give comparable energy by weight, but diesel is denser and hence gives more energy per liter. The aspects listed above are the key aspects that determine the efficiency of a fuel for diesel engines. There are other aspects/characteristics which do not have a direct bearing on the performance, but are important for reasons such as environmental impact etc. These are: • Ash Percentage - Ash is a measure of the amount of metals contained in the fuel. High concentrations of these materials can cause injector tip plugging, combustion 26 deposits and injection system wear. The ash content is important for the heating value, as heating value decreases with increasing ash content. Ash content for bio-fuels is typically lower than for most coals, and sulphur content is much lower than for many fossil fuels. Unlike coal ash, which may contain toxic metals and other trace contaminants, biomass ash may be used as a soil amendment to help replenish nutrients removed by harvest. • Sulfur Percentage - The percentage by weight, of sulfur in the fuel Sulfur content is limited by law to very small percentages for diesel fuel used in on-road applications. (20) 6.5 Review of biodiesel feedstocks In general, biodiesel feedstock can be categorized into three groups: vegetable oils (edible or non-edible oils), animal fats, and used waste cooking oil including triglycerides. But also a variety of oils can be used to produce biodiesel, algae, which can be grown using waste materials such as sewage and without displacing land currently used for food production and oil from halophytes such as salicornia bigelovii, which can be grown using saltwater in coastal areas where conventional crops cannot be grown, with yields equal to the yields of soybeans and other oilseeds grown using freshwater irrigation. Many advocates suggest that waste vegetable oil is the best source of oil to produce biodiesel, but since the available supply is drastically less than the amount of petroleumbased fuel that is burned for transportation and home heating in the world; this local solution does not scale well. (21) 27 6.6 Vegetable oils as diesel fuels The concept of using vegetable oil as a transportation fuel dates back to 1893 when Dr. Rudolf Diesel developed the first diesel engine to run on vegetable oil. Vegetable oil is one of the renewable fuels. Vegetable oils have become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. Vegetable oils have the potential to substitute a fraction of petroleum distillates and petroleum-based petro chemicals in the near future. The basic constituent of vegetable oils is triglyceride. Vegetable oils comprise 90 to 98% triglycerides and small amounts of mono- and diglycerides .These usually contain free fatty acids (FFAs), water, sterols, phospholipids, odorants and other impurities. Different types of vegetable oils have different types of fatty acids. The advantages of vegetable oils as diesel fuel are their portability, ready availability, renewability, higher heat content (about 88% of D2 fuel), lower sulfur content, lower aromatic content, and biodegradability. The main disadvantages of vegetable oils as diesel fuel are higher viscosity, lower volatility, and the reactivity of unsaturated hydrocarbon chains. The injection and atomization characteristics of the vegetable oils are significantly different than those of petroleum-derived diesel fuels, mainly as the result of their high viscosities. The vegetable oils, as alternative engine fuels, are all extremely viscous with viscosities ranging from 9 to 17 times greater than that of petroleum-derived diesel fuel. Modern diesel engines have fuel-injection system that is sensitive to viscosity change. One way to avoid these problems is to reduce fuel viscosity of vegetable oil in order to improve its performance. The vegetable oils may be blended to reduce the viscosity with diesel in presence of some additives to improve its properties. Heating and blending of vegetable oils may reduce the viscosity and improve volatility of vegetable oils but its molecular structure remains unchanged hence polyunsaturated character remains. Blending of vegetable oils with diesel, however, reduces the viscosity drastically and the fuel handling system of the engine can handle vegetable oil–diesel blends without any problems. The conversion of vegetable oils into FAME is an effective way to overcome all the problems associated with the vegetable oils. The most common way of producing biodiesel is the transesterification of vegetable oils. The methyl ester produced by transesterification of vegetable oil has a high cetane number, low viscosity and improved heating value compared to those of pure vegetable oil which results 28 in shorter ignition delay and longer combustion duration and hence low particulate emissions. Its use results in the minimization of carbon deposits on injector nozzles. 6.7 Transesterification of vegetable oil Transesterification is the process of separating the fatty acids from their glycerol backbone to form fatty acid esters (FAE) and free glycerol [Meher, et al., 2006; Morrison and Boyd, 2005; Abhullah, etal., 2007]. Fatty acid esters commonly known as biodiesel can be produced in batches or continuously by transesterifying triglycerides such as animal fat or vegetable oil with lower molecular weight alcohols in the presence of a base or an acid catalyst. This reaction occurs stepwise, with monoglycerides and diglycerides as intermediate products. The transesterification process of converting vegetable oils to biodiesel is shown in Figure 8. The "R" groups are the fatty acids, which are usually 12 to 22 carbons in length. The large vegetable oil molecule is reduced to about 1/3 its original size, lowering the viscosity making it similar to diesel fuel. The resulting fuel operates similar to diesel fuel in an engine. The reaction produces three molecules of an ester fuel from one molecule of vegetable oil. Figure 6.7: The transesterification process of converting vegetable oils to biodiesel (22)http://www.ag.ndsu.edu/pubs/ageng/machine/ae1240w.htm 29 In such reaction known as transesterification, a triglyceride is allowed to react with a threefold excess of an alcohol such as ethanol or methanol, and this alcohol takes the place of the ester linkage to glycerol, yielding three fatty acid esters of the new alcohol and glycerol. Above the process using methanol is shown in figure 8. Here three molecules of one alcohol are replacing glycerol, another alcohol, in the triglyceride. Vegetable oils have to undergo the process of transesterification to be usable in internal combustion engines. Biodiesel is the product of the process of transesterification. Biodiesel is biodegradable, non-toxic and essentially free from sulfur; it is renewable and can be produced from agriculture and plant resources. Biodiesel is an alternative fuel, which has a correlation with sustainable development, energy conservation, management, efficiency and environmental preservation. Transesterification is the reaction of a fat or oil with an alcohol to form esters and glycerol. Alcohol combines with the triglycerides to form glycerol and esters. A catalyst is usually used to improve their action rate and yield. Since the reaction is reversible, excess alcohol is required to shift the equilibrium to the product side. Among the alcohols that can be used in the transesterification process are methanol, ethanol, propanol, butanol and amyl alcohol. The process of transesterification brings about drastic change in viscosity of vegetable oil. The biodiesel thus produced by this process is totally miscible with mineral diesel in any proportion. Biodiesel viscosity comes very close to that of mineral diesel hence no problems in the existing fuel handling system. Flash point of the biodiesel gets lowered after esterification and the cetane number gets improved. Even lower concentrations of biodiesel act as cetane number improver for biodiesel blend. Calorific value of biodiesel is also found to be very close to mineral diesel. Some typical observations from the engine tests suggested that the thermal efficiency of the engine generally improves; cooling losses and exhaust gas temperature increase, smoke opacity generally gets lower for biodiesel blends. Possible reason may be additional lubricity properties of the biodiesel; hence reduced frictional losses (FHP). The energy thus saved increases thermal efficiency, cooling losses and exhaust losses from the engine. The thermal efficiency starts reducing after a certain concentration of biodiesel. Flash point, density, pour point, cetane number, calorific value of biodiesel comes in very close range to that of mineral diesel. 30 6.8 Biodiesel production from used cooking oil The methods used for biodiesel production from used cooking oil are similar to that of conventional transesterification processes. Selection of a particular process depends on the amount of free fatty acid and water content of the used cooking oil. It is reported that the feedstock such as refined vegetable oil, crude vegetable oil , used cooking oil ,animal oil and trap greases generally contain 0.05%, 0.3%– 0.7%, 5%–30% and 40%–100% of free fatty acid respectively [Canakciand Van Gerpen, 2001; Enweremadu and Mbarawa, 2009]. Most biodiesel production processes can tolerate up to 1% water in the feedstock, even this small quantity of water will increase soap formation and measurably affect the transesterification process [Canakci and Ozsezen, 2005; Freedman et al., 1984]. At present, production of vegetable oil and animal fat worldwide is not sufficient to replace liquid fossil fuel use. There are a few environmental groups who protest the increased amount of farming and the subsequent over-fertilization, increased pesticide use, and land use conversion necessary to produce the additional vegetable oil. Waste vegetable oil has been proposed by many as the best source of oil to produce biodiesel. Here too, the available supply is far less than the quantity needed to replace the amount of petroleum-based fuel that is burned for transportation and home heating in the world. According to the United States Environmental Protection Agency (EPA), restaurants in the US produce about 300 million US gallons (1,000,000 m³) of waste cooking oil annually. For a genuinely renewable energy source, plants would have to be considered. Plants convert solar energy into chemical energy through photosynthesis. Biodiesel ultimately stores this chemical energy and releases it on combustion. The carbon dioxide and water produced can participate in the photosynthetic cycle, so that plants can offer a sustainable oil source for biodiesel production. The rate of oil production is different for each plant. As a biofuel, plant oils will always be preferable to animal fats. (23) 31 Table 6.8: Comparison of properties of waste cooking oil, biodiesel from waste cooking oil and commercial diesel fuel. (24 Source: http://www.sciencedirect.com/.pdf Biodiesel from waste cooking oil via base-catalytic and supercritical methanol transesterification Ayhan Demirbas * Sila Science, Trabzon 61040, Turkey) Fuel property Waste vegetable oil Biodiesel from waste Commercial diesel fuel vegetable oil Kinematic viscosity 36.4 5.3 1.9–4.1 Density (kg/L, at 288 K) 0.924 0.897 0.075–0.840 Flash point (K) 485 469 340–358 Pour point (K) 284 262 254–260 Cetane number 49 54 40–46 Ash content (%) 0.006 0.004 0.008–0.010 Sulfur content (%) 0.09 0.06 0.35–0.55 Carbon residue (%) 0.46 0.33 0.35–0.40 Water content (%) 0.42 0.04 0.02–0.05 Higher heating value 41.40 42.65 45.62–46.48 Free fatty acid (mg KOH/g oil) 1.32 0.10 - Iodine value 141.5 - - (mm2/s, at 313 K) (MJ/kg) 32 Table 6.8 shows comparison of properties of waste cooking oil, biodiesel from waste cooking oil and commercial diesel fuel. The properties of biodiesel and diesel fuels, in general, show many similarities, and therefore, biodiesel is rated as a realistic fuel as an alternative to diesel. This is due to the fact that the conversion of waste cooking oil into methyl esters through the transesterification process approximately reduces the molecular weight to one third, reduces the viscosity by about one-seventh, reduces the flashpoint slightly and increases the volatility marginally, and reduces pour point considerably. 33 Chapter 7 Biodiesel as an engine fuel 7.1 Overview The best way to use vegetable oil as fuel is to convert it in to biodiesel. Biodiesel is the name of clean burning mono-alkyl ester-based oxygenated fuel made from natural, renewable sources such as new/used vegetable oils and animal fats. The resulting biodiesel is quite similar to conventional diesel in its main characteristics. Biodiesel contains no petroleum products, but it is compatible with conventional diesel and can be blended in any proportion with mineral diesel to create a stable biodiesel blend. The level of blending with petroleum diesel is referred as Bxx, where xx indicates the amount of biodiesel in the blend (i.e. B10 blend is10% biodiesel and 90% diesel. It can be used in CI engine with no major modification in the engine hardware. 7.2 Technical characteristics of biodiesel as a transportation fuel Biodiesel is a cleaner burning alternative to petroleum-based diesel fuel. Just like petroleumbased diesel fuel, biodiesel operates in the compression ignition (diesel) engines. The successful introduction and commercialization of biodiesel in many countries around the world has been accompanied by the development of standards to ensure high product quality and user confidence. Some biodiesel standards are ASTM D6751 (ASTM = American Society for Testing and Materials) and the European standard EN14214. The biodiesel is characterized by determining its physical and fuel properties including density, viscosity, iodine value, acid value, cloud point, pure point, gross heat of combustion and volatility. In general, biodiesel compares well to petroleum-based diesel. The advantages of biodiesel as diesel fuel are its portability, ready availability, renewability, higher combustion efficiency, lower sulfur and aromatic content, higher cetane number and higher biodegradability. The main disadvantages of biodiesel as diesel fuel are its higher viscosity, lower energy content, higher cloud point and pour point, higher nitrogen oxide emission, lower engine speed and power, injector coking, engine compatibility, high price, and higher engine wear. Biodiesel offers safety benefits over diesel fuel because it is much less combustible, with a flash point 34 greater than 423 ⁰ K compared to 350 ⁰ K for petroleum-based diesel fuel. Biodiesel has a higher cetane number (around 50) than diesel fuel, no aromatics, no sulfur, and contains 10– 11% oxygen by weight. The cetane number is a commonly used indicator for the determination of diesel fuel quality, especially the ignition quality. It measures the readiness of the fuel to auto-ignite when injected into the engine. Ignition quality is one of the properties of biodiesel that is determined by the structure of the fatty acid methyl ester (FAME) component. Viscosity is the most important property of biodiesel since it affects the operation of the fuel injection equipment, particularly at low temperatures when the increase in viscosity affects the fluidity of the fuel. Biodiesel has a viscosity close to that of diesel fuels. High viscosity leads to poorer atomization of the fuel spray and less accurate operation of the fuel injectors. Elemental composition and relative amounts of compounds present in biodiesel and diesel fuel are given in Tables 2 and 3.Due to presence of electronegative element oxygen, biodiesel is slightly more polar than diesel fuel as a result viscosity of biodiesel is higher than diesel fuel. Presence of elemental oxygen lowers the heating value of biodiesel when compared the diesel fuel. The lower heating value (LHV) is the most common value used for engine applications. It is used as an indicator of the energy content of the fuel. Biodiesel generally has a LHV that is 12% less than No. 2 diesel fuel on a weight basis (16,000 Btu/lb compared with18,300 Btu/lb). Since the biodiesel has a higher density, the LHV is only 8% less on a volume basis (118,170 Btu/gallon for biodiesel compared with 129,050 Btu/gallon for No. 2 diesel fuel).Biodiesel can be used as pure fuel or blended at any level with petroleum-based diesel for use by diesel engines. The most common biodiesel blends are B2 (2% biodiesel and 98% petroleum diesel),B5 (5% biodiesel and 95% petroleum diesel), and B20 (20%biodiesel and 80% petroleum diesel). The technical disadvantages of biodiesel/petroleum diesel blends include problems with fuel freezing in cold weather, reduced energy density, and degradation of fuel under storage for prolonged periods. Biodiesel blends up to B20 can be used in nearly all diesel equipment and are compatible with most storage and distribution equipment. These low level blends generally do not require any engine modifications. Higher blends and B100 (pure biodiesel) may be used in some engines with little or no modification, although the transportation and storage of B100 requires special management. The characteristics of biodiesel are close to mineral diesel, and, therefore, biodiesel becomes a strong candidate to replace the mineral diesel if the need arises. The conversion of triglycerides into methyl or ethyl esters through the transesterification process reduces the 35 molecular weight to one-thirds that of the triglycerides, the viscosity by a factor of about eight and increases the volatility marginally. Biodiesel has viscosity close to mineral diesel. This vegetable oil esters contain10–11% oxygen by weight, which may encourage combustion than hydrocarbon-based diesel in an engine. The cetane number of biodiesel is around50. Biodiesel has lower volumetric heating values (about 10%) than mineral diesel but has a high cetane number and flash point. The esters have cloud point and pour points that are 15–25 1C higher than those of mineral diesel. Table 7.2: Properties of Biodiesel prepared from vegetable oils 36 7.3 Engine performance characteristics of biodiesel Biodiesel has low heating value, (10% lower than diesel) on weight basis because of presence of substantial amount of oxygen in the fuel but at the same time biodiesel has a higher specific gravity (0.88) as compared to mineral diesel (0.85) so overall impact is approximately 5% lower energy content per unit volume. Thermal efficiency of an engine operating on biodiesel is generally better than that operating on diesel. Brake-specific energy consumption (bsec) is a more reliable criterion compared to brake-specific fuel consumption (bsfc) for comparing fuels having different calorific values and densities. Several experimental investigations have been carried out by researchers around the world to evaluate the engine performance of different biodiesel blends. Masjuki et al. investigated preheated palm oil methyl esters (POME) in the diesel engine. They observed that by preheating the POME above room temperature, the engine performance, especially the brake power output and exhaust emission characteristics improved significantly. Scholl and Sorenson studied the combustion of soya bean oil methyl ester (SME) in a direct injection diesel engine. They found that most of the relevant combustion parameters for SME such as ignition delay, peak pressure, and rate of pressure rise were close to those observed for diesel combustion at the same engine load, speed, timing and nozzle diameter. They also investigated combustion and emissions characteristics with SME and diesel for different injector orifice diameter. It was found that ignition delay for the two fuels were comparable in magnitude, and the ignition delay of SME was found to be more sensitive to nozzle diameter than diesel. CO emissions from SME were slightly lower, Hydrocarbon emissions reduced drastically, NOx for two fuels were comparable and smoke numbers for the SME were lower than that of diesel. Altin et al. investigated the use of sunflower oil, cottonseed oil, soya bean oil and their methyl esters in a single cylinder, four-stroke direct injection diesel engine. The variations of maximum engine torque values in relation with the fuel types are shown in Fig. 20. The maximum torque with diesel operation was 43.1Nm at 1300 rpm. For ease of comparison, this torque was assumed 100% as reference. The observed maximum torque values of the vegetable oil fuel operations were also at about1300 rpm but less than the diesel fuel value for each fuel. The maximum power with diesel fuel operation was 7.45kW at 1700 rpm. As before, this power was assumed 100% as reference. Observed maximum power values of the vegetable oil fuel operations were also at about 1700 rpm but less than the diesel fuel value for each fuel. These results may also be due to the higher viscosity and 37 lower heating values of vegetable oils. Specific fuel consumption is one of the important parameters of an engine and is defined as the consumption per unit of power in a unit of time. Specific fuel consumption values of the methyl esters were generally less than those of the raw vegetable oils. The higher specific fuel consumption values in the case of vegetable oils are due to their lower energy content. 7.4 Engine emissions from biodiesel Since biodiesel is free from sulfur hence less sulfate emissions and particulate reduction is reported in the exhaust. Due to near absence of sulfur in biodiesel, it helps reduce the problem of acid rain due to transportation fuels. The lack of aromatic hydrocarbon (benzene, toluene etc.) in biodiesel reduces unregulated emissions as well like ketone, benzene etc. Breathing particulate has been found to be hazard for human health, especially in terms of respiratory system problem. PM consists of elemental carbon (≈31%), sulfates and moisture(≈14%), unburnt fuel (≈7%), unburnt lubricating oil (≈40%) and remaining may be metals and others substances. Smoke opacity is a direct measure of smoke and soot. Various studies show that smoke opacity for biodiesel is generally lower. Several experimental investigations are performed on 4-stroke DI diesel engines with vegetable oil methyl esters and found that hydrocarbon emissions are much lower in case of biodiesel compared to diesel. This is also due to oxygenated nature of biodiesel where more oxygen is available for burning and reducing hydrocarbon emissions in the exhaust. CO is a toxic combustion product resulting from incomplete combustion of hydrocarbons. In presence of sufficient oxygen, CO is converted intoCO2. Biodiesel is an oxygenated fuel and leads to more complete combustion; hence CO emissions reduce in the exhaust. Altin et al. reported that CO emission for biodiesel is marginally higher in comparison to diesel. 38 Figure7.4: B100 emissions compared to petroleum diesel emissions by percentage (U.S. Department of Energy National Renewable Energy Laboratory, Biodiesel Handling and Use Guidelines) 7.5 Environmental Benefits of Biodiesel Fuel The steadily rising price of petroleum products and the environmental impact of procuring, manufacturing, and using them create the need for alternate energy sources. Biodiesel, fuel that is chemically prepared from vegetable oil, provides an environmentally friendly substitute for diesel fuel. It is classified as a biofuel because it originates from a biological source. Its biological origin makes it biodegradable and nontoxic. Other advantages of biodiesel fuel over petroleum diesel are the increased oxygen content, no sulfur content, increased lubricity, and lower emissions of particulate matter upon combustion. The Clean Air Act of 1990 mandates oxygenated additives to be added to gasoline in cities with excessive levels of ozone and carbon monoxide pollution because they lead to a reduction in carbon monoxide emissions. Biodiesel contains about 11% oxygen by mass so no additional oxygenated additives are necessary. A later ruling by the Environmental Protection Agency in 1994 required that 30% of the oxygenated additives to reformulated gasoline (gasoline whose composition has been altered to reduce concentrations of undesirable substances) be from renewable resources, and the most popular additive, methyl tertiary-butyl ether, MTBE, is made from methanol, a nonrenewable source. This ruling supports the use of ethanol, which is produced largely from corn, in place of the methanol, but biodiesel is another renewable source of an oxygenated additive. Absence of sulfur content is desirable because 39 sulfur indirectly increases carbon monoxide emissions by coating the catalytic converter, reducing its efficiency in catalyzing complete combustion of the gasoline to carbon dioxide. The increased lubricity provided by biodiesel, even in blends as low as 3%, prolongs engine life, with less frequent need for engine part replacement. Particulate matter is carbon and soot, so lowering these emission levels leads to cleaner air also. One of the most attractive aspects of biodiesel use is that is provides a means of recycling carbon dioxide, so there is no net increase in global warming. As with any complete combustion, carbon dioxide and water are the end products, but these will be taken up by the plant to ultimately lead to production of new biodiesel. Fossil fuels, which took millions of years to form, are not replenishable in the near future, whereas biofuels can ideally be replenished in one growing season. Figure 7.5 shows a very simple cycle of carbon of biodiesel and fossil fuel with different time frames. Although diesel fuel can be written into a similar cycle, the time frames are entirely different, so that diesel fuel is not renewable in a reasonable time period. (25) Figure 7.5: A simple cycle of carbon dioxide of biodiesel and fossil fuel with different time frames ( 26 http://www.uic.edu/classes/chem/clandrie/orgolabs/CASPiE/CASPiE_assets/biodiesel1_module.pdf) 40 7.6 Environmental benefits in comparison to petroleum based fuels include Biodiesel is the only alternative fuel to have fully completed the health effects testing requirements of the Clean Air Act. The use of biodiesel in a conventional diesel engine results in substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter compared to emissions from diesel fuel. In addition, the exhaust emissions of sulfur oxides and sulfates (major components of acid rain) from biodiesel are essentially eliminated compared to diesel. Of the major exhaust pollutants, both unburned hydrocarbons and nitrogen oxides are ozone or smog forming precursors. The use of biodiesel results in a substantial reduction of unburned hydrocarbons. Emissions of nitrogen oxides are either slightly reduced or slightly increased depending on the duty cycle of the engine and testing methods used. Based on engine testing, using the most stringent emissions testing protocols required by EPA for certification of fuels or fuel additives in the US, the overall ozone forming potential of the speciated hydrocarbon emissions from biodiesel was nearly 50 percent less than that measured for diesel fuel. • Carbon monoxide emissions are reduced around 50% and carbon dioxide by around 78% overall based on the fact that the carbon comes from carbon already present in the earth’s atmosphere, not from its crust, as in petrodiesel. • Fewer aromatic hydrocarbons are present – a 56% reduction in benzofluoranthene and 71% reduction in benzopyrenes. • Particulate emissions are reduced by up to 65%, leading to reduced cancer risks of up to 94% according to tests sponsored by the Department of Energy. • Its higher cetane rating than petrodiesel causes more rapid ignition when injected into the engine. It also has the highest energy content of any alternative fuel in its pure form (B100). • Biodiesel is biodegradable and non-toxic - tests sponsored by the United States Department of Agriculture confirm biodiesel is less toxic than table salt and biodegrades as quickly as sugar. • Pure biodiesel (B100) can be used in any petroleum diesel engine, though it is more commonly used in lower concentrations. The recent mandates for ultra-low sulfur petrodiesel 41 make it necessary to use additives to increase lubricity and flow properties, so biodiesel is an obvious choice. Even the 2% formulation (B2) is capable of restoring lubricity to the fuel. B5 is often used in snow removal equipment and other municipal systems. Biodiesel is less flammable than gasoline or petrodiesel. Its flash point (>150 °C) is much higher than that of petroleum diesel (64 °C) or gasoline (−45 °C). (27) 7.7 Some challenges for using biodiesel fuel • Biodiesel has higher nitrogen oxide NOx emissions than petrodiesel. The higher NOx emissions may be due to the higher cetane rating and oxygen content of the fuel, so that atmospheric nitrogen is oxidized more readily. Catalytic converters and properly tuned engines can reduce these emissions. • While the flash point of biodiesel is higher than that of gasoline or petrodiesel, its gel point of varies depending on the ester composition. Most biodiesel has a somewhat higher gel and cloud point than petrodiesel. This requires the heating of storage tanks, especially in cooler climates. • Water contamination: Biodiesel is hydrophilic because of its oxygen content that permits hydrogen bonding of water molecules. Water that is not removed during processing or present from storage tank condensation causes problems because: - It reduces the heat of combustion of the fuel, leading to more smoke, harder starting, and less power. - It leads to corrosion of vital fuel system components: fuel pumps, injector pumps, fuel lines, etc. - It freezes to form ice crystals near 0 °C (32 °F), which are sites for gel formation of the fuel, decreasing its flow properties. The growth of microbe colonies, which can plug up a fuel system, is increased by water presence. This is an ongoing problem for biodiesel users with heater fuel tanks13. (27) 42 Chapter 8 Biodiesel Economy 8.1 Overview: The technical and economic advantages of biodiesel are that, it reduces greenhouse gas emissions because it reduces some exhaust emissions; it helps to reduce a country’s reliance on crude oil imports and supports agriculture by providing a new labor and market opportunities for domestic crops; it enhances the lubricating property; it is safer to handle, being less toxic, more biodegradable and it is widely accepted by vehicle manufacturers. The economic benefits of a biodiesel industry would include value added to the feedstock, an increased number of rural manufacturing jobs, increased income taxes, increased investments in plant and equipment, an expanded manufacturing sector, an increased tax base from plant operations and income taxes, improvement in the current account balance, and reductions in health care costs due to improved air quality and greenhouse gas mitigation. The major economic factor to consider for input costs of biodiesel production is the feedstock, which is about 80% of the total operating cost. Other important costs are labor, methanol and catalyst, which must be added to the feedstock. The cost of biodiesel fuels varies depending on the base stock, geographic area, variability in crop production from season to season, the price of crude petroleum and other factors. Biodiesel can be over double the price of petroleum Diesel. The high price of biodiesel is in large part due to the high price of the feedstock. However, biodiesel can be made from other feedstocks, including used vegetable oil, beef tallow, pork lard and yellow grease. Biodiesel has become more attractive recently because of its environmental benefits. With cooking oils used as raw material, the viability of a continuous transesterification process and recovery of high quality glycerol as a biodiesel by product are primary options to be considered to lower the cost of biodiesel. With recent increases in petroleum prices and uncertainties concerning petroleum availability, there is renewed interest in vegetable oil fuels for Diesel engines. Most of the biodiesel that is currently made uses soybean oil, methanol and an alkaline catalyst. The high value of soybean oil as a food product makes production of a cost effective fuel 43 very challenging. However, there are large amounts of low cost oils and fats such as restaurant wastes and animal fats that could be converted to biodiesel. The problem with processing these low cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot be converted to biodiesel using an alkaline catalyst. A review of 12 economic feasibility studies shows that the projected costs for biodiesel (BD) from oilseed or animal fats have a range US $0.30–0.69/l, including meal and glycerin credits and the assumption of reduced capital investment costs by having the crushing and/or esterification facility added onto an existing grain or tallow facility. Rough projections of the cost of BD from vegetable oil and waste grease are respectively,US$0.54–0.62/l and US$0.34–0.42/l. With pre-tax Diesel priced at US$0.18/l in the US and US$0.20–0.24/l in some European countries, BD is, thus, currently not economically feasible, and more research and technological development will be needed. Biodiesel is a technologically feasible alternative to petrodiesel, but nowadays biodiesel costs 1.5 to 3 times more than fossil diesel in developed countries. Biodiesel is more expensive than petrodiesel, though it is still commonly produced in relatively small quantities (in comparison to petroleum products and ethanol). The competitiveness of biodiesel to petrodiesel depends on the fuel taxation rates and policies. Generally, the production costs of biodiesel remain much higher than those of petrodiesel. Therefore, biodiesel is not competitive with petrodiesel under current economic conditions. The competitiveness of biodiesel relies on the price of the biomass feedstock and costs associated with the conversion technology. Moreover, Low production costs of crude oil derivatives are another crucial handicap for the biodiesel marketing. In this sense, the continuous increase of crude oil prices approaches biodiesel production cost to those ones of fossil diesel, converting this difference from handicap to a potential opportunity for enhancing the bio-diesel application. Figure 8.1 shows the evolution of fossil diesel prices in EU. (28) 44 Figure 8.1: Price of fossil diesel (commercial use) Euro/l (28 http://ftp.jrc.es/EURdoc/eur20279en.pdf) 8.2 Biodiesel production economic balance Several (non-technological) limiting factors have been stopping until now the development of the bio-diesel industry. These limiting factors are feedstock prices, bio-diesel production costs, crude oil prices and taxation of energy products. 8.2.1 Feedstock prices No matter the technological process adopted for bio-diesel manufacturing, the largest share of production cost of bio-diesel is the feedstock cost. The feedstock cost is the major obstacle to the market feasibility of bio-diesel. Rape-seed, used in bio-diesel sector, covers around half of the non-food area under set-aside scheme. 8.2.2 Biodiesel production costs The estimated costs for biodiesel can be split up into fixed and variable costs. Fixed costs come from extracting the vegetable oil from seed and processing this vegetable oil into biodiesel. These costs include manufacturing, capital, and labor costs. Glycerol and protein meal for livestock feed are byproducts that might help to offset the cost of biodiesel production. The sale of these byproducts is considered fixed income. Rape-seed price (Pr) is considered as а variable one. It is also considered that manufacturing 1 litre of bio-diesel needs 2.23 kg. rapeseed on average basis. 45 Table 8.2.2: Bio-diesel cost production depending on rape-seed price in Euro/l (Sources: ATLAS Database, US National Renewable Energy Laboratory (NREL), IPTS data gathering & elaboration) Fixed costs Manufacturing costs Capital costs (annualised) Staff and overhead costs 0.005 0.147 0.012 0.005 Fixed income By-products income TOTAL fixed factors 0.084 0.080 Variable costs 1 liter of bio-diesel requires 2.23 kg of rape-seed TOTAL PRODUCTION COSTS Remark: (Pr) - rapeseed price Pr*2.23 0.08 + Pr*2.23 By assuming the reference rape-seed price of 0.214 Euro/kg, a net cost of 0.557 Euro/l biodiesel is obtained. Three salient facts have to be underlined with respect to this cost structure: • First of all, the largest share in the final costs belongs to the procurement costs of bio- mass. In the above case, the share of the rape-seed cost in the final product is about 70 %. Other reports, quoted by the US NREL, state a raw material cost share up to 90 % of the total cost. This share mainly depends on the assumptions made about the prices of raw bio-mass. • The second salient fact is that the sale of by-products is an important source of income, which rises significantly the competitiveness of the overall process. In the above scenario, the income from by-products consists of about 15 % of the total production costs. Other reports state for this figure even 35 % share of the total production cost. • At the last, but not at the least, when making cost and price comparisons between bio- diesel and fossil diesel, a parameter, reflecting the fuel consumption substitution ratio between bio-diesel and fossil diesel, ensuing from their different energy content, should be applied. (28) 46 8.2.3 Taxation of energy products There is no harmonized European policy, either for fossil fuels or for bio-fuels. Each Member State implements own domestic regulations, inside the EU framework for taxation of energy products. The minimum levels of taxation are modified depending on whether these motor fuels are used for certain industrial or commercial purposes. The proposal refers to: agriculture and forestry; stationary motors; plant and machinery, used in construction; civil engineering and public works; vehicles, intended for use off the public roadway; passenger transport and captive fleets, which provide services to public bodies. On the other hand, Member States may apply total or partial tax exemptions or reductions for energy products used under fiscal control in pilot projects for technological development. Also, such preferences might be applied for more environmentally-friendly products or in relation to fuels from renewable sources, e.g. bio-diesel. (28) 47 Chapter 9 Experimental part - The production of biodiesel from rapeseed oil experiment...............................................................................................................9.1 - Fuel analytics experiments: Determining some properties of Rapeseed oil, Diesel and two types of biodiesel one produced in the Lab and the other from the gas station; density, kinematic viscosity, lower calorific value and oxidation stability......................................................................................................................9.2 - The Emission testing experiment for rapeseed oil, low sulfur diesel fuel and biodiesel (from gas station).......................................................................................9.6 Experiments were performed in the lab of the University of Applied Science (HAW), Amberg, Germany Nov.2010-Feb.2011. 48 9.1 The production of biodiesel from rapeseed oil experiment Figure 9.1: Biodiesel produced in the Lab. 9.1.1 Pressing of Rapeseed oil. 1.2 Kg of, seven- year- old rapeseed, was pressed which gave 500 ml of Rapeseed oil and the pressed oil was filtered using filter paper for 24 hours. 50 ml of the filtered oil was used for the determination of the free fatty acid percentage. Figure 9.1.1.1: Rapeseed oil press in lab 49 Figure 9.1.1.2: The filtration of 50 ml of rapeseed oil in lab 9.1.2 The determination of free fatty acid 10 grams of the filtered rapeseed oil was put in 250 ml Erlenmeyer flask, and then 50 ml of diethyl ether and ethanol were added. Stirring was done until the oil was completely dissolved in the solvent mixture. A burette was filled with about 10-15 ml of ethanolic KOH solution, 3-4 drops of phenolphthalein (1% in ethanol) and a magnetic stir bar were given to the solution in the Erlenmeyer flask, and then the KOH solution was added to the mixture (mixture titration).When the color of the mixture changed, the mixture was left another 30 second to be sure of the new color. - A formula was used to determine the concentration of free fatty acid in Rapeseed oil: % free fatty acid = a * avg.mol.wght. / 10 * E where: a: volume [ml] of KOH * 0.1 [mol / ml] avg.mol.wght.: 314 g / mol E: initial weight in grams 50 A computer program of Biodiesel, shown in figure 8.2, was used to determine the amounts of addition of methanol and KOH for esterification Figure 9.1.2: Biodiesel RME-Rechner (29 Chemical Engineering department, HAW) 9.1.3 Transestrification: The rapeseed oil was heated up to 30 oC, and was put on a stir, the KOH was dissolved in the Methanol and slowly the methanol-KOH was allowed into the oil in drops and the oil was left to the next day. 9.1.4 Thin layer chromatography: A good way to check for impurities; how many different compounds are in a sample, very small quantities of the samples are placed on the special TLC plates. The plate is put in a container with a solvent or solvent mixture, the solvent runs up the plate and will separate the different kinds of molecules based on polarity differences and size differences. 51 There are two phases of Thin layer chromatography a stationary phase (a solid, or a liquid supported on a solid) and a mobile phase (a liquid or a gas). The mobile phase flows through the stationary phase and carries the components of the mixture with it. Different components travel at different rates. The stationary phase in this case is silica gel coated on a thin piece of rigid plastic. The mobile phase in this case is a mixture of solvents hexane and ethyl acetate in a specific ratio (v/v). (30) Figure 9.1.4: Thin layer chromatography device in the Lab. (31 Thin layer chromatography device in the Lab Lab of chemical engineering department in HAW) 52 9.2 Fuel analytics: Determining some properties of Rapeseed oil, Diesel and two types of Biodiesel; one produced in the Lab and the other from the gas station; density, kinematic viscosity, lower calorific value and oxidation stability 9.2.1 Introduction A reliable operation of combustion engines is only possible, when important characteristics and substances of content of the fuel are defined. These properties have to fulfil certain limiting values, otherwise guaranty and warranty agreement for proper engine operation or the conformity with relevant emissions regulations cannot be given. Besides that, defined fuel qualities are essential for the evaluation of operation characteristics and the ongoing development of engine technique. The specification of fuel quality by the use of consistent parameters and testing methods also enables fuel improvement, if necessary. Moreover, the comparison of engines’ emission behaviour is only possible when certified fuels (reference fuels) are used. Finally a defined fuel quality is basis for trading fuels. (32) 9.2.2 Technical Details and Standards of diesel and biodiesel There are three existing specification standards for diesel & Biodiesel fuels (EN590, DIN 51606 & EN14214). EN590 (actually EN590:2000) describes the physical properties that all diesel fuel must meet if it is to be sold in the EU, Czech Republic, Iceland, Norway or Switzerland. It allows the blending of up to 5% Biodiesel with 'normal' DERV - a 95/5 mix. DIN 51606 is a German standard for Biodiesel, is considered to be the highest standard currently existing, and is regarded by almost all vehicle manufacturers as evidence of compliance with the strictest standards for diesel fuels. The vast majority of Biodiesel produced commercially meets or exceeds this standard. EN14214 is the standard for biodiesel now having recently been finalized by the European Standards organisation CEN. It is broadly based on DIN 51606. 53 Table 9.2.2: Some properties of diesel and biodiesel standards ( 33 http://www.biodieselfillingstations.co.uk/approvals.htm) Properties Density @ Unit Derv ( EN590) Biodiesel Biodiesel (DIN51606) (EN14214) g/cm³ 0.82-0.86 0.875-0.9 0.86-0.9 Viscosity @ 40°C mm²/s 2.0-4.5 3.5-5.0 3.5-5.0 Flashpoint °C >55 >110 >101 Sulphur % mass 0.20 <0.01 <0.01 Carbon Residue (% weight) 0.30 <0.03 <0.03 Total Contamination mg/kg Unknown <20 <24 Cetane Number - >45 >49 >51 15°C Derv: diesel oil used in cars and lorries with diesel engines; from d(iesel) e(ngine) r(oad) v(ehicle) 54 9.2.3 Kinematic Viscosity measurement: The Ubbelohde viscometer Viscosity refers to a fluid’s resistance to flow at a given temperature. A fuel that is too viscous can hinder the operation of an engine. Kinematic viscosity measures the ease with which a fluid will flow under force. It is different from absolute viscosity, also called dynamic viscosity. Kinematic viscosity is obtained by dividing the dynamic viscosity by the density of the fluid. If two fluids with the same absolute viscosity are allowed to flow freely on a slope, the fluid with higher density will flow faster because it is heavier. The density of biodiesel varies depending on its feedstock. Longer and straighter chains (saturated fats) tend to have higher density than shorter and unsaturated molecules. Kinematic viscosity allows comparison between the engine performance of different fuels, independent of the density of the fuels. Two fuels with the same kinematic viscosity should have the same hydraulic fuel properties, even though one fuel may be denser than the other. The highest acceptable kinematic viscosity for biodiesel as specified in D6751 is 6.0. EN 14214, the biodiesel standard for the European market, specifies a viscosity limit for biodiesel of 3.5–5.0 mm 2/s. If a batch of biodiesel does not meet this specification, the viscosity can be corrected by blending it with a fuel that has a lower or higher viscosity. The Ubbelohde type viscometer, shown in figure 9.6, is a measuring instrument which uses a capillary based method of measuring viscosity. The device was invented by the German chemist Leo Ubbelohde (1877-1964).The Ubbelohde viscometer is a u-shaped piece of glassware with a reservoir on one side and a measuring bulb with a capillary on the other. A liquid is introduced into the reservoir then sucked through the capillary and measuring bulb. The liquid is allowed to travel back through the measuring bulb and the time it takes for the liquid to pass through two calibrated marks is a measure for viscosity. The Ubbelohde device has a third arm extending from the end of the capillary and open to the atmosphere. In this way the pressure head only depends on a fixed height and no longer on the total volume of liquid. The advantage of this instrument is that the values obtained are independent of the concentration. (34) 55 Figure9.2.3: The Ubbelohde viscometer (35 http://www.thefullwiki.org/Viscometer) Table 9.2.3: Experimental results of kinematic viscosity for rapeseed oil, two types of biodiesel and diesel fuel Fuel type Kinematic viscosity (mm2/s) Rapeseed oil 36.22 Biodiesel (lab) 5.706 Biodiesel (gas station) 4.454 Diesel 3.095 Table 9.2.3 shows the experimental results of kinematic viscosity for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed from the table that the rapeseed oil has the highest viscosity among the other fuels because vegetable based oils tend to be fairly viscous and don’t flow too easily. Also, it could be noticed that diesel has lowest viscosity. Biodiesel of the two types has higher viscosity than diesel specially the one produced in the 56 lab because not all of rapeseed oil was converted completely to biodiesel, it had a little amount of rapeseed oil and it’s known that rapeseed oil has high viscosity. 9.2.4 Density Measurement: Hydrometer and Pycnometer Density is the weight per unit volume. Diesel fuels have higher densities and therefore it gives more energy than that of the petrol. The densities of the vegetable oils are higher, but during the transesterification process the density is decreased, however they are denser than the diesel fuels and thereby they are an efficient alternative. (36) 9.2.4.1 Hydrometer: A hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to be tested is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a scale inside the stem, so that the specific gravity can be read directly. A variety of scales exist, and are used depending on the context. Figure9.2.4.1: Hydrometer (37 http://en.wikipedia.org/wiki/Hydrometer) 57 9.2.4.2 Pycnometer A pycnometer is a small flask with a glass stopper. A capillary opening which runs along the length of the stopper makes it possible to fill the pycnometer completely- that is, without leaving a bubble of air in the flask. Figure 9.2.4.2: Pycnometer (38 http://en.wikipedia.org/wiki/File:PycnometerEmpty.jpg) Table 9.2.4: Experimental results of Density for rapeseed oil, two types of biodiesel and diesel fuel Density Fuel type Hydrometer Rapeseed oil Biodiesel (lab) g / cm³ Pycnometer 0.921 0.922 0.880 0.879 Biodiesel (gas station) - Diesel - 0.885 0.825 58 Table 9.2.4 shows the experimental results of Density for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed for rapeseed oil and biodiesel produced in the lab, density was measured by hydrometer and pycnometer, it can be noticed that rapeseed oil has the highest density because vegetable oils are denser in their chemical structure. Also, it could be noticed that diesel and biodiesel have close densities, with higher density for biodiesel due to the fact that biodiesel is made out of vegetable oil and that it is not converted to 100% biodiesel. 9.2.5 Heating value Measurement: the Bomb Calorimeter Heating value or Heat of combustion is the amount of heating energy released by the combustion of a unit value of fuels. The most important determinants of the heating value are the moisture content. It is because of this, that the purified Biodiesel is dried. The moisture content of the Biodiesel is low and this increases the heating value of the fuel.(39,40) A bomb calorimeter is a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured. Electrical energy is used to ignite the fuel; as the fuel is burning, it will heat up the surrounding air, which expands and escapes through a tube that leads the air out of the calorimeter. When the air is escaping through the copper tube it will also heat up the water outside the tube. The temperature of the water allows for calculating calorie content of the fuel. The calorimeter gives the value of the high heating value or the GROSS (or higher) calorific value for a fuel. The net calorific value is then obtained by subtracting the latent heat of the water present from the gross calorific value. The latent heat of vaporization of water is 2.5 MJ/kg. 59 Figure 9.2.5: Bomb Calorimeter (41 http://en.wikipedia.org/wiki/Calorimeter) Table 9.2.5: Experimental results of Lower heating value for rapeseed oil, two types of biodiesel and diesel fuel Fuel type Lower heating value (kJ/kg) Rapeseed oil 36922 Biodiesel (lab) 37510 Biodiesel (gas station) 38105 Diesel 46221 Table 9.2.5 shows the experimental results of Lower heating value for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed that diesel has the highest heating value, which means that the energy released of diesel combustion is the highest, while biodiesel comes in the second place of amount of energy released and the last one is the rapeseed oil. 60 9.2.6 Measuring the oxidation stability: Because of the chemical structure of fatty acid methyl esters (FAME), they age more quickly than fossil diesel fuels. Therefore it was considered to include a limit for oxidation stability in the existing quality standard for biodiesel. Oxidative stability is an important parameter in the characterization of fats and oils. Transestrification of vegetable oils with methanol produces the methyl esters of the fatty acids (together with glycerol as a byproduct). These have only a limited shelf-life as they are slowly oxidized by atmospheric oxygen. The resulting oxidation products can cause damage to combustion engines. This is why oxidation stability is an important quality criterion for biodiesel, which needs to be regularly determined during production. With the Rancimat this determination can be carried out quickly and simply, and the value is given in hours. The fuel sample is heated up to 110⁰ C, compressed air is supplied through the fuel into a flask with distilled water. Conductivity of the distilled water is measured; when it raises the fuel begins to deteriorate. The point at which the conductivity curve bends as shown in Figure 9.2.6.1 (the red line) is defined as the oxidation stability. The oxidation stability of diesel is measured differently from rapeseed oil and biodiesel. Diesel is heated up to 95°C for 16 hours and exposed to 3 liter per hour of pure oxygen (accelerated aging), because of the aging resin will be formed in the diesel (deterioration of diesel), the concentration of resin in the diesel is measured and the value is given in gram per cubic meter.(42) Figure 9.2.6: The Rancimat device (43 http://www.springerlink.com/content/g811177h40r6344p/) 61 Table 9.2.6: Experimental results of Oxidation stability for rapeseed oil, two types of biodiesel and diesel fuel Fuel type Oxidation stability (hours) Rapeseed oil 3.03 Biodiesel (lab) 18.78 Biodiesel (gas station) 7.640 Diesel 16.38 Table 9.2.6 shows the experimental results of Oxidation stability for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed from table 9.2.6 that the oxidation stability for rapeseed oil is 3.03 hours, and in the standard results for rapeeed oil, shown in table 9.4.1, the minimum is five hours, this due to that the rapeseed oil which was used in the lab was not a fresh one, it was one year old oil. For the oxidation stability of biodiesel which was produced in the lab, The value isn’t reasonable (18.78). There’s a very big difference between the standard value (6 h) shown in table 9.4.3 (6 hours), this could be due to a fault in the experiment e.g. compressed air which was supplied to the biodiesel could have failed for some hours during the night. For biodiesel, from gas station, it could be noticed that the oxidation stability result shown in table 9.2.6 (7.640 hours), is close to the European Standard EN 14214 of biodiesel shown in table 9.4.3 (6 hours) this is because it’s commercial biodiesel which is sold in gas stations, where it should meet the standards of biodiesel. For diesel fuel the oxidation stability is measured in a different way than that for rapeseed oil and biodiesel, here the result of oxidation stability for diesel which was got from the lab, was done by the rancimant method as for rapeseed oil and biodiesel but it’s not accurate for diesel. The oxidation stability for diesel according to the standard method couldn’t not be performed in the lab because the experiment needs pure oxygen, which gives a very flammable mixture together with diesel and the lab is not equipped for that. 62 Figure 9.2.6.1: The oxidation stability graph of rapeseed oil Figure 9.2.6.2: The oxidation stability graph of biodiesel (from gas station) 63 Figure 9.2.6.3: The oxidation stability graph of biodiesel (produced in lab) Figure 9.2.6.4: The oxidation stability graph of diesel fuel Figures from 9.2.6.until 9.2.6.4 show the oxidation stability of rapeseed oil, two types of biodiesel (from lab and gas station) and diesel fuel respectively. The red line shows the point at which the conductivity curve bends which is defined as the oxidation stability. 64 9.3 CHNS Elemental Analyzer (EA): CHNS elemental analyzers provide a means for the rapid determination of carbon, hydrogen, nitrogen and sulphur in organic matrices and other types of materials. They are capable of handling a wide variety of sample types, including solids, liquids, volatile and viscous samples, in the fields of pharmaceuticals, polymers, chemicals, environment, food and energy. The analyzers are often constructed in modular form such that they can be set up in a number of different configurations to determine, for example, CHN, CHNS, CNS or N depending on the application. This adaptability allows not only flexibility of operation but also the use of a wide range of sample weights from a fraction of a milligram to several grams (macro-systems.) Basic principles In the combustion process (furnace at ca. 1000oC), carbon is converted to carbon dioxide; hydrogen to water; nitrogen to nitrogen gas/ oxides of nitrogen and sulphur to sulphur dioxide. If other elements such as chlorine are present, they will also be converted to combustion products, such as hydrogen chloride. A variety of absorbents are used to remove these additional combustion products as well as some of the principal elements, sulphur for example, if no determination of these additional elements is required. The combustion products are swept out of the combustion chamber by inert carrier gas such as helium and passed over heated (about 600o C) high purity copper. This copper can be situated at the base of the combustion chamber or in a separate furnace. The function of this copper is to remove any oxygen not consumed in the initial combustion and to convert any oxides of nitrogen to nitrogen gas. The gases are then passed through the absorbent traps in order to leave only carbon dioxide, water, nitrogen and sulphur dioxide. Detection of the gases can be carried out in a variety of ways including (i) a GC separation followed by quantification using thermal conductivity detection (ii) a partial separation by GC (‘frontal chromatography’) followed by thermal conductivity detection (CHN but not S) (iii) a series of separate infra-red and thermal conductivity cells for detection of individual 65 compounds. Quantification of the elements requires calibration for each element by using high purity ‘micro-analytical standard’ compounds such as acetanilide and benzoic acid.(44) More specifications about the CHNS Elemental Analyzer are shown in Appendix A, A.9. Figure 9.3: CHNS-O Elemental Analyzer (45 http://www.cecri.res.in/CIF/cif.htm) Table 9.3.1: Elementary analyzer results for biodiesel produced in Lab. 66 Table 9.3.1 shows an example of the results of carbon, hydrogen, nitrogen and sulphur contents for biodiesel produced in the lab of the elementary analyzer device. Three results of three samples of biodiesel are shown in the figure. The samples were made and put into the elementary analyzer, to make sure that the device is working well and that good results are given and that was shown from the close results that were got for the three samples. Then these results are entered into the calorimeter device to get the lower heating value of the biodiesel which is shown in table 9.6 as 37510 kJ/kg. Table 9.3.2: Elementary analyzer results for diesel fuel and rapeseed oil 67 Table 9.3.2 shows the results of carbon, hydrogen, nitrogen and sulphur contents for diesel fuel and rapeseed oil of the elementary analyzer device. Three results of three samples of biodiesel are shown in the table. The samples were made and put into the elementary analyzer, to make sure that the device is working well and that good results are given and that was shown from the close results that were got for the three samples. Table 9.3.3: Elementary analyzer results for biodiesel (gas station) 68 Table 9.3.3 shows the results of carbon, hydrogen, nitrogen and sulphur contents for biodiesel, which was bought from gas station, of the elementary analyzer device. Three results of three samples of biodiesel are shown in the table. The samples were made and put into the elementary analyzer, to make sure that the device is working well and that good results are given and that was shown from the close results that were got for the three samples. Then these results are entered into the calorimeter device to get the lower heating value of this biodiesel 69 9.4 Experimental and Standard results of Density, Kinematic viscosity, Lower heating value and Oxidation stability for rapeseed oil, two types of biodiesel and diesel fuel Table 9.4.1: Characteristic properties for Rapeseed 0il according to DIN 51 605 - German Rapeseed Oil Fuel Standard (46 http://www.biofuelsb2b.com/useful) Properties Unit Limiting Value Min. Max. Density (15ºC) kg/m3 900 930 Kinematic mm2/S - 38 kJ/kg 35000 - h 5.0 - Viscosity (40ºC) Calorific Value Oxidation Stability (110ºC) 70 Table 9.4.2: Characteristic properties for Rapeseed 0il according to experiments done in the Lab. of the FachHochSchule, Amberg 2010/2011 Properties Unit Value kg/m3 921 Density (15ºC) Hydrometer 922 Pycnometer mm2/s 36.22 Lower heating value kJ/kg 36922 Oxidation h 3.03 Kinematic Viscosity (40ºC) Stability (113ºC) Table 9.4 shows the results of the density, the kinematic viscosity, the lower heating value and the oxidation stability of rapeseed oil, and comparing these results with the standard results of rapeseed oil according to the DIN 51 605 - German Rapeseed Oil Fuel Standard which are shown in table 8.3, it can be noticed that the results are so close to each other, except for the oxidation stability. In the standard results, the min. is five hours and the result that was got in the Lab. It’s three hours and this due to that the rapeseed oil which was used in the lab was not a fresh one, it was a one year old oil. 71 Table 9.4.3: Characteristic properties for Biodiesel according to European Standard EN 14214. (47www.biofuels2b2.com) Properties Unit European Standard EN 14214 Density g / cm³ 0.86 - 0.90 ( 15°C) Viscosity at 40°C , mm²/s min 3.5 5.0 max Lower kJ/kg 36000 h 6.0 Heating Value Oxidation stability 110°C 72 Table 9.4.4: Characteristic properties for two types of Biodiesel, one produced in the lab. of the Fachhochschule, Amberg 2010,/2011 and the other one was bought from the gas station. Properties Unit Value Biodiesel (Lab) Biodiesel (gas station) Hydrometer 0.880 - Pycnometer 0.879 0.885 Viscosity at 40°C , 5.706 4.454 Density ( 15°C) g / cm³ mm²/s min max Lower Heating Value kJ/kg 37510 38105 Oxidation h 18.78 7.640 stability 110°C Table 9.4.4 shows the results of the density, the kinematic viscosity, the lower heating value and the oxidation stability of two types of biodiesel, one is produced in the Lab and the other one was bought from the gas station. It can be noticed that results are close to each other except for the oxidation stability, which is very high for the biodiesel produced in the lab. This is due to the fact that the biodiesel which is bought from the gas station has higher quality than the biodiesel produced in the Lab because once the reaction of the tranesterification is completed, some additional steps take place other than the separation of biodiesel and 73 glycerin which was done only in the Lab, such as the removal of the excess alcohol in glycerin and biodiesel phases is removed with a flash evaporation process or by distillation and Methyl Ester Wash. The biodiesel is sometimes purified by washing gently with warm water to remove residual catalyst or soaps, dried, and sent to storage, resulting in a clear amber-yellow liquid with a viscosity similar to petrodiesel.This was seen clearly in the photos taken for the two types of biodiesel. Comparing these results with the standard results of biodiesel, shown in table 9.5 according to the European Standard EN 14214, it can be noticed that the results for the biodiesel bought from the gas station are closer to the standard ones than the other type of biodiesel produced in the Lab, because the commercial fuel must meet any required specifications. Table 9.4.5: Characteristic properties for Diesel according to the DIN EN 590 standards, July1999. Properties Unit Value Min. Density kg / m³ Max. 820 845 2.00 4.50 ( 15°C) Viscosity at 40°C , mm²/s min max Lower Heating kJ/kg 42500 g/ml 25 Value Oxidation stability 110°C 74 Table 9.4.6: Characteristic properties for Diesel according to according to experiments done in the Lab. of the FachHochSchule, Amberg, 2010/2011 Properties Unit Value Density (pycnometer) g / cm³ 0.825 Viscosity at 40°C mm²/s 3.095 Lower Heating Value kJ/kg 46221 Oxidation h 16.38 ( 15°C) stability 110°C Table 9.4.6 shows the results of the density, the kinematic viscosity, the lower heating value and the oxidation stability of Diesel fuel, and comparing these results with the standard results of Diesel fuel according to the DIN EN 590 standards, July1999, which are shown in table 9.7, it can be noticed that the results are so close to each other, except for the oxidation stability. In the standard results, it’s measured in grams per cubic meters and not in hours as in the standard results for rapeseed oil and biodiesel because the oxidation stability for diesel is measured differently as was mentioned previously. Here the result of oxidation stability for diesel which was got from the lab, was done by the rancimant method and it’s not accurate for diesel. Unfortunately, the oxidation stability for diesel according to the standard method couldn’t not be performed in the Lab because the experiment needs pure oxygen, which gives a very flammable mixture together with diesel and the Lab is not equipped for that. 75 9.5 Discussion of results: Comparing between experimental and standard of the fuel analytics results of rapeseed oil, diesel and biodiesel. For the biodiesel which was produced from rapeseed oil in the Lab, it could be noticed that it’s not of high quality. That could be noticed from the color of the biodiesel compared to the commercial biodiesel (from the gas station). Also, the oxidation stability experiment (18.78 h) could show the low quality of biodiesel produced in the lab because comparing it to commercial biodiesel (7.64 h). That is due to the fact that commercial biodiesel undergoes additional steps once the transestrification is completed, such as the removal of the excess alcohol in glycerin and biodiesel phases is removed with a flash evaporation process or by distillation and Methyl Ester Wash. Also, the biodiesel is sometimes purified by washing gently with warm water to remove residual catalyst or soaps, dried, and sent to storage, resulting in a clear amber-yellow liquid with a viscosity similar to petro-diesel, which is the color of the commercial biodiesel. Figure 9.5.1: Biodiesel from gas station Figure 9.5.2: Biodiesel produced in the lab 76 For the results of the properties that were determined for rapeseed oil, diesel and two types of biodiesel (produced in lab and from gas station), which were the density, the kinematic viscosity, the lower calorific value and the oxidation stability. These results were compared to the standard values. For rapeseed oil, it could be noticed that most of the experimental results of the density, the kinematic viscosity, and the lower calorific value shown in table 9.4, are very close to the German Rapeseed Oil Fuel Standard DIN 51 605 shown in table 9.3. For the experimental result of the oxidation stability, it can be noticed that in the standard results, the min. is five hours and the result that was got in the lab was three hours and this due to that the rapeseed oil which was used in the lab was not a fresh one, it was one year old oil. For biodiesel, from gas station, it could be noticed that most of the experimental results of the density, the kinematic viscosity, the lower calorific value and the oxidation stability shown in table 9.6, are very close to the European Standard EN 14214 of biodiesel shown in table 9.5. This is because it’s commercial biodiesel which is sold in gas stations, where it should meet the standards of biodiesel. For biodiesel, produced in the lab and as was mentioned before, it’s not of high quality as commercial biodiesel. It could be noticed from the experimental results shown in table 9.6, of the density, and the lower heating value that they are close to the European Standard EN 14214 of biodiesel. But for the kinematic viscosity, it could be noticed that the experimental result (5.706 mm²/s) is a little bit higher than the max. of the standard value (5 mm²/s ) and this because the biodiesel produced in the lab was not converted completely to biodiesel, it had a little amount of rapeseed oil and it’s known that rapeseed oil has high viscosity, so that’s why the biodiesel had higher viscosity. For the oxidation stability, there’s a very big difference between the standard value (6 h) and the experimental one (18.78 h). This value is too high to be reasonable, this could be due to a fault in the experiment e.g. compressed air which was supplied to the biodiesel could have failed for some hours during the night. For diesel fuel, it could be noticed that most of the experimental results of the density, the kinematic viscosity, and the lower calorific value shown in table 9.8, are very close to the DIN EN 590 standards of diesel shown in table 9.7. This is because it’s commercial diesel which is sold in gas stations, where it should meet the standards of diesel fuel. But for the oxidation stability, in the standard results, it’s measured in grams per cubic meters and not in hours as in the standard results for rapeseed oil and biodiesel, this is because the oxidation stability for diesel is measured in a different way than that for rapeseed oil and biodiesel. Here the 77 result of oxidation stability for diesel which was got from the lab, was done by the rancimant method as for rapeseed oil and biodiesel but it’s not accurate. Unfortunately, the oxidation stability for diesel according to the standard method couldn’t not be performed in the lab because the experiment needs pure oxygen, which gives a very flammable mixture together with diesel and the lab is not equipped for that. 78 9.6 The Emission testing experiment for rapeseed oil, low sulfur diesel fuel and biodiesel (from gas station). 9.6.1 Equipment used: 1- Engine used: Tractor Diesel engine of type Kubota 05 Series D1105-E3B, it is a three cylinder swirl chamber engine with a total displacement of 1.1 liter. The engine is used for driving a generator to produce electricity; waste heat of the engine is used for heating (co-generation unit). Electric and thermal power of co-generation unit respectively are 5 and 12 Kw, respectively. (48) More specifications about engine can be found in Appendix B, B.1 Figure 9.6.1.1: Kubota diesel engine 79 2- MLT 4 Multi-Component Gas Analyzer MLT 4 Multi-Component Gas Analyzer is a multi-component, multi-method analysis using infrared, ultraviolet, thermal conductivity, paramagnetic and electrochemical sensor technologies. Housed in a 19-inch enclosure (thermostatically-controlled option), the MLT 4 Gas Analyzer can measure up to five gas components by combining the different technologies into one unit. (49) More specifications about this device can be found in Appendix B, B.2 The version of the MLT 4 gas analyzer which is used at the Fachhochschule, is equipped with NDIR and UV/ VIS analyzers for O2, CO2, CO, NO, NO2, SO2, H2 AND CH4. NDIR: Non dispersive infrared sensor UV: Ultra Violet VIS: Visual light spectrometer Figure 9.6.1.2: MLT 4 Gas analyzer 80 3- Total Hydrocarbon Analyzer (THC) The Total Hydrocarbon Analyzer is designed especially for mobile use at various sites and operating conditions both for continuous and short monitoring. Features of the total hydrocarbon analyzer include measuring ranges from 1 ppm to 100,000 ppm, internal air supply and a patented miniature heated sensor block with a flame ioni- sation detector controlled up to 240° C, making it possible to measure in steam saturated gases. The instrument is suitable for compliance to national reference measuring methods and regulations for emission measuring and for the efficiency control of thermal, catalytic, biological and activated carbon exhaust air purifying plants and other emission sources, permitting control of these processes. (50) More specifications are shown in Appendix B, B.3 The THC analyzer measures according to the hot FID principle. FID: Flame ionization detector Figure 9.6.1.3:: Total hydrocarbon analyzer 81 4- BRIGON - Smoke Tester: The BRIGON-Smoke is a device for determining the smoke number. It is easy to handle, lightweight and reliable instrument. The smoke tester forces a gas sample to cross the filter paper and leave a soot spot, which is then compared with smoke scale to determine smoke number. High smoke number is an obvious symptom of incomplete combustion and may have various reasons, as well as serious consequences (air pollution, soot disposition on heat exchange surfaces, fuel waste, etc.) The contents of this smoke tester include smoke tester, filter paper, smoke scale and lubricant oil. (51) More specifications about this device can be found in AppendixB, B.4. Figure 9.6.1.4: Smoke tester device 82 9.6.2 Procedure of the emission testing experiment In this experiment, the emissions of three fuels, were measured and compared in a diesel engine. Rapeseed oil, diesel fuel and biodiesel fuel from gas station were used in the experiment. The emissions the gas analyzer measured were: SO2, CO, O2, CO2, and NOx which was the sum of NO and NO2.Hydrocarbons of fuels were measured alone by the hydrocarbon analyzer device. The reading of hydrocarbons was changed every five seconds and three readings were taken in three different times as shown in table 9.9. The mean value of the three readings was recorded in table 8.10 for total hydrocarbons. For the soot measurement, it was measured by the smoke tester device, which was mentioned previously in section 9.3.2 in the used equipment part. Three samples were taken from the exhaust on a filter paper for every fuel by the smoke tester device. Actually it can be seen from figure 9.16 that there are four samples on the filter paper, three are numbered and one is without a number. The one without a number is the first sample taken to clean the exhaust. After that by using a detecting device, it was possible to determine the soot or smoke number for every sample and the mean value of the three values was taken. Figure 9.6.2.1: Smoke / soot samples in lab 83 Figure 9.6.2.2: Densitometer (device for determining the smoke number) and the smoke scale in lab The diesel engine of type Kubota 05 Series D1105-E3B was turned on, the engine’s speed was1500 rpm and the electric load was 5 Kw at full load. The first fuel was used was the rapeseed oil, the average time for every fuel was 15 minutes in the engine. Measurements of the emissions were taken after the temperatures of the engine’s cooling water and exhaust were stable. Three measurements of hydrocarbons were taken at three different times as shown in table 8.9. Then three samples of ash or soot were taken on a filter paper and ash or smoke number was measured by a detecting device. The gas analyzer took measurements every 5 seconds for 15 minutes and the file of the emission measurements was saved on a special computer program to calculate the mean values. The same procedure was used for diesel and biodiesel fuels. 84 9.6.3 Tabulated Results of the emission testing experiment Table 9.6.3.1: Three different readings for the total hydrocarbons in three different times and three different readings for ash number for every fuel. Fuel type Ash number (samples) Total hydrocarbons (ppm) @ different times Rapeseed oil 10 @ Diesel 7@ 9 @ 9:48 10 @ 9:55 6.7 6.8 6.9 6.5 @ 10:25 6 @ 10:34 5.0 5.3 6.5 4.6 @ 10:58 4.6 @ 11:03 5.4 5.8 5.7 9:43 10:17 Biodiesel 4.5 @ 10:25 Table 9.6.3.1shows three different readings of the total hydrocarbons at three different times for rapeseed oil, diesel and biodiesel. It can be noticed that there is no big difference in the readings for every fuel. Also, it can be noticed that the rapeseed oil has the highest readings of the total hydrocarbons while the biodiesel has the lowest readings which is reasonable. For the smoke number, it can be noticed that rapeseed oil also has the highest readings, while diesel and biodiesel readings are close to each other, but the biodiesel smoke number for biodiesel is a little bit higher than diesel. 85 Table 9.6.3.2: The values of cooling water temperature, the exhaust temperature, the mean values of the total hydrocarbons and the smoke number for every fuel. Fuel type Cooling water temperature ⁰C Exhaust Total temperature hydrocarbons ppm (Mean ⁰C value) Filter smoke number (Mean value) Rapeseed oil 72 277 9.67 6.80 Diesel 75 273 6.50 5.60 Biodiesel 77 269 4.57 5.63 Table 9.6.3.2 shows the values of the total hydrocarbons of the rapeseed oil, diesel and biodiesel, it can be noticed that the biodiesel has the lowest value of hydrocarbons and this was expected due to oxygenated nature of biodiesel where more oxygen is available for burning and reducing hydrocarbon emissions in the exhaust. 86 Table 9.6.3.3 Mean values of the resulted emissions for every fuel Fuel type SO2 NO NO2 NOx CO O2 Vol.-% ppm ppm ppm ppm ppm (Mean (Mean (Mean (Mean (Mean (Mean value value) value) value) value) value CO2 Vol.-% (Mean value Rapeseed oil 18,225 480 27,980 507,98 281,85 10,800 7,505 Diesel 18,850 541 33,500 574,50 88,650 10,675 7,445 Biodiesel 18,865 529,5 35,250 564,75 99,950 10,715 7,485 Table 9.6.3.3 shows the mean values of the resulted emissions for every fuel that were measured by the gas analyzer. For SO2, O2 and CO2 it can be noticed that the values for every fuel are almost similar. For NOx, it can be noticed that the rapeseed oil has the lowest value of NOx, while diesel has the highest value. The higher NOx emissions may be due to the higher cetane rating and oxygen content of the fuel, so that atmospheric nitrogen is oxidized more readily. For CO, it is noticed that biodiesel has more value of CO than diesel and higher CO emission means that the combustion was not done completely. 87 9.6.4 Graphical Results: Comparing the emissions of rapeseed oil, diesel and biodiesel Figure 9.6.4.1 : Resulted SO2 emissions for rapeseed oil, diesel and biodiesel Figure 9.6.4.2: Resulted NOx emissions for rapeseed oil, diesel and biodiesel 88 Figure 9.6.4.3: Resulted CO emissions for rapeseed oil, diesel and biodiesel Figure 9.6.4.4: Resulted O2 emissions for rapeseed oil, diesel and biodiesel 89 Figure 9.6.4.5: Resulted CO2 emissions for rapeseed oil, diesel and biodiesel Figure 9.6.4.6: Resulted hydrocarbon emissions for rapeseed oil, diesel and biodiesel 90 Figure 9.6.4.7: Resulted filter smoke number for rapeseed oil, diesel and biodiesel Figures from 9.6.4.1 until 9.6.4.7 show the graphs of the experimental results of SO2, NOx, CO, O2, CO2, unburned hydrocarbons and the smoke number respectively for rapeseed oil, biodiesel and diesel fuel. 91 9.6.5 Discussion of Results: Comparing between the results of the emission testing experiment of diesel and biodiesel fuels For SO2, and as was mentioned before in section 7.4, biodiesel is free from sulfur hence produces less sulfate emissions, but according to the experimental results of SO2 emissions which are shown in table 9.11 and figure 9.18, it can be noticed that the SO2 emission of biodiesel is too high, actually biodiesel has the highest value of SO2 when compared to diesel and rapeseed oil in figure 9.18. Well, definitely this was a wrong result because the SO2 channel of the gas analyzer was not calibrated due to the lack of reference gas for SO2. Moreover, the diesel which was used is a low-sulfur diesel, which also proves that the results that were got were wrong ones. For the NOx, which are the sum of NO and NO2 emissions, and as was mentioned before in section 7.7, biodiesel has higher nitrogen oxide NOx emissions than petrodiesel. The higher NOx emissions may be due to the higher cetane rating and oxygen content of the fuel, so that atmospheric nitrogen is oxidized more readily. According to the experimental results of NOx emissions, it can be noticed from table 9.11 and figure 9.19, that the biodiesel has lower NOx emissions than diesel. For CO emissions, and as was mentioned in section 7.4, CO emissions are reduced in the exhaust when using biodiesel fuel, because biodiesel contains more oxygen than diesel fuel and this results in complete combustion. According to the experimental results, it can be noticed from table 9.11 and figure 9.20, that biodiesel has higher CO emissions than diesel, and this means that the combustion for biodiesel was not a complete one, and hence produced more CO emissions than diesel fuel. For the CO2, and as was mentioned in section 7.6, that One of the most attractive aspects of biodiesel use is that it provides a means of recycling carbon dioxide, so there is no net increase in global warming. As with any complete combustion, carbon dioxide and water are the end products, but these will be taken up by the plant to ultimately lead to production of new biodiesel. According to the experimental results, it can be noticed from table 9.11 and figure 9.22, that biodiesel and diesel have very close values of CO2 emissions, but the biodiesel is slightly higher, maybe this is due to the fact that biodiesel has to burn more hydrocarbons, to give the same amount of energy that the diesel fuel does, because it has less heating value than diesel, and because of that more CO2 is produced. For the O2, the experimental results for diesel and biodiesel are close to each, biodiesel has slightly higher value, and this is because of the oxygenated nature of biodiesel where more oxygen is available for burning. For the hydrocarbon emissions, as was 92 mentioned in section 7.4, hydrocarbon emissions are much lower in case of biodiesel compared to diesel. This is due to oxygenated nature of biodiesel where more oxygen is available for burning and reducing hydrocarbon emissions in the exhaust the use of biodiesel results in a substantial reduction of un-burned hydrocarbons, and according to the experimental results, it can be noticed from table 9.10 and figure 9.23 that the hydrocarbon emissions of biodiesel are lower than those for hydrocarbons by almost 30% which means the hydrocarbons emissions are reduced when using biodiesel fuel compared to diesel fuel For the Filter smoke number or as was mentioned in section 7.4, the smoke opacity which is a direct measure of smoke and soot. Various studies show that smoke opacity for biodiesel is generally lower. According to the experimental results shown in table 9.10 and figure 9.24, it can be noticed that diesel and biodiesel have almost the same mean value of the smoke number; maybe this is due to the lack of oxygen in the combustion of diesel and biodiesel and because both fuels have similarity in characteristics. 93 Chapter 10 Summary The study of this Master thesis was about the manufacturing of biodiesel from the waste vegetable oil. This study showed that biodiesel is an environmentally friendly due to its less polluting and renewable nature compared with conventional petroleum diesel fuel. Moreover, it could be used in any diesel engine without modification. Biodiesel could be made out of pure or waste vegetable through a transesterification process in the presence of a catalyst. The purpose of the transesterification process is to lower the viscosity of the oil, which is better for the engine performance. Biodiesel esters are characterized by their physical and fuel properties including density, viscosity, iodine value, acid value, cloud point, pure point, gross heat of combustion, and volatility. Biodiesel fuels produce slightly lower power and torque and consume more fuel than diesel fuel. Biodiesel is better than diesel fuel in terms of sulfur content, flash point, aromatic content, and biodegradability (Bala, 2005). The cost of biodiesels varies depending on the base stock, geographic area, variability in crop production from season to season, the price of crude petroleum, and other factors. Biodiesel is more than twice as expensive as petroleum diesel. The high price of biodiesel is in large part due to the high price of the feedstock. However, biodiesel can be made from other feedstocks of low cost oils and fats such as restaurant waste and animal fats that could be converted into biodiesel. The problem with processing these low-cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot be converted into biodiesel using an alkaline catalyst (Demirbas, 2003; Canakci and Van Gerpen, 2001).If the biodiesel valorized efficiently at energy purpose, so would be benefit for the environment and the local population, job creation, provision of modern energy carriers to rural communities. Many experiments were performed on biodiesel in the lab; the first one was producing the biodiesel from the rapeseed oil. The biodiesel produced wasn’t of high quality as the commercial biodiesel or biodiesel from the gas station. This is due to the fact that commercial biodiesel which was produced in the lab didn’t undergo under additional steps once the transestrification is completed as for commercial biodiesel; e.g. the removal of the excess alcohol in glycerin and biodiesel phases with a flash evaporation process or by distillation 94 and Methyl Ester Wash. Also washing gently with warm water to remove residual catalyst or soaps, dried, and sent to storage, resulting in a clear amber-yellow liquid with a viscosity similar to petro-diesel. From figures 10.1 and 10.2, it could be noticed the difference in colors between the biodiesel from gas station and biodiesel produced in the lab. Figure 10.1: Biodiesel from gas station Figure 10.2: Biodiesel produced in the lab For the fuel analytics, the properties of density, kinematic viscosity, lower calorific value and oxidation stability for Rapeseed oil, Diesel and two types of Biodiesel were tested and compared to standard values. For rapeseed oil, it was noticed that most of the experimental results matched the German Rapeseed Oil Fuel Standard DIN 51 605 except for the oxidation stability, it can be noticed that in the standard results, the minimum was five hours and the result that was got in the lab was three hours and this due to that the rapeseed oil which was used in the lab was not a fresh one, it was one year old oil. For biodiesel, from gas station, it was noticed that most of the experimental results matched the European Standard EN 14214 of biodiesel .This was because it’s a commercial biodiesel which is sold in gas stations, where it should meet the standards of biodiesel. For biodiesel, produced in the lab and as was mentioned before that it wasn’t of high quality as commercial biodiesel, the experimental results of the density, and the lower heating value were very close to the European Standard EN 14214 of biodiesel. But for the kinematic viscosity, it was noticed that the experimental result (5.706 mm²/s) was a little bit higher than the maximum of the standard value (5 mm²/s). That was because the biodiesel produced in the lab was not converted completely to biodiesel, it had a little amount of rapeseed oil and it’s known that rapeseed oil has high viscosity, so that’s why the biodiesel had higher viscosity. For the oxidation stability, there was a very big difference between the standard value (6 hours) and the experimental one (18.78 hours). This value was too high to be reasonable, this could be due to a fault in the experiment e.g. compressed air which was 95 supplied to the biodiesel could have failed for some hours during the night. For diesel fuel, it was noticed that most of the experimental results were very close to the DIN EN 590 standards of diesel that was because it’s a commercial diesel which is sold in gas stations, where it should meet the standards of diesel fuel. But for the oxidation stability, it was noticed that in the standard results it was measured in grams per cubic (g/m3) meters and not in hours (h) as in the standard results for rapeseed oil and biodiesel, this is due to the fact that the oxidation stability for diesel is measured in a different way than that for rapeseed oil and biodiesel. The experimental result of oxidation stability for diesel which was got from the lab was done by the rancimat method as for rapeseed oil and biodiesel but it was not accurate for diesel. Unfortunately, the oxidation stability for diesel according to the standard method couldn’t not be performed in the lab because the experiment needs pure oxygen, which gives a very flammable mixture together with diesel and the lab is not equipped for that. For the emissions testing experiment, the emissions of SO2, CO, O2, CO2, NO and NO2 were tested using the MTL 4 gas analyzer, also the total hydrocarbons were tested by the total hydrocarbon analyzer device and the soot or smoke number was tested by the smoke tester device for rapeseed oil, biodiesel (from gas station) and diesel fuel. The comparison of the emissions was made between biodiesel and diesel fuels. It was noticed from emissions testing experiment that the experimental results didn’t match what was said in theory about the emissions of diesel and biodiesel as in section 7.4, 7.5 and 7.6. The only reduction that was noticed was in the unburned hydrocarbons by almost 30% and the NOx. It was noticed also that emissions of SO2 of biodiesel were too high in spite of the fact that biodiesel id free from sulfur. This result was a wrong one because the SO2 channel of the gas analyzer was not calibrated due to the lack of reference gas for SO2 in the gas analyzer. For CO, it was noticed that biodiesel had higher emissions than diesel fuel and this meant that the combustion for biodiesel was not a complete one because there was not enough oxygen, and hence produced more CO emissions than diesel fuel. This might be because the engine that was used in the experiment was not adapted to biodiesel use. Also, CO2 emissions of biodiesel were close to those of diesel fuel, and according to theory, there should be reduction in CO2 emissions. Maybe this is due to the fact that biodiesel has to burn more hydrocarbons, to give the same amount of energy that the diesel fuel does, because biodiesel has less heating value than diesel, and because of that more CO2 is produced. The measurement of the smoke number for biodiesel was not accurate, biodiesel and diesel had very close values of smoke number and according to theory, biodiesel should have less smoke number. Maybe the changes of the smoke number were too small to be detected at certain conditions. 96 Chapter 11 Conclusion and Recommendations In a world where every action must be weighed against its demerits, where everything should be balanced between power and the environment, in a world like today, where petroleum reserves are becoming limited and will eventually run out and the critical issue of oil peak and the environmental concerns, all have prompted deeper research into the area of alternatives to fossil fuels which are biofuels such as biodiesel and bioethanol. Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. Biodiesel is briefly defined as the monoalkyl esters of vegetable oils or animal fats. Biodiesel is the best candidate for diesel fuels in diesel engines. It burns like petroleum diesel as it involves regulated pollutants. So it necessary to implement the use of biodiesel over the current petroleum and gasoline because of all the merit and advantages it brings forth to the table. In comparison to petroleum and gasoline, biodiesel beats its competitors in all categories of toxic substance emissions and poses close to no threat to the environment. What's more, instead of increasing the carbon dioxide levels in the atmosphere, the overall production and use of biodiesel consumes more carbon dioxide than it emits, thus making it a valuable tool in preventing global warming. Not only does petroleum diesel harm our environment through emissions of toxic substances, but it also has negative affects on us physically. Many health problems and illnesses have been traced back to emissions from petroleum diesel. These emissions have been related to many cases of cancer, cardiovascular and respiratory disease, asthma and infections in the lungs. By using biodiesel in the place of petroleum diesel, not only will we be helping the environment with a much better alternative, but we would be significantly reducing many health risks. The fact that most biodiesels are domestically produced means that by using more of it, the market of biodiesel would actually stimulate the economy, reducing a country’s dependence on foreign oil imports. Also, the implementation of biodiesel is extremely easy and requires little or no modifications to the typical diesel engine, making it a very easy and smooth transition. 97 When we weigh the advantages of biofuel against its disadvantages, it is clear that it brings more than it takes away because biofuels are easily available from common biomass sources, carbon dioxide cycle occurs in combustion, they are very environmentally friendly, and they are biodegradable and contribute to sustainability (Puppan, 2002). It is true that commercial food are used to make biodiesel but if there is a surplus of it, why not put the excess to better use. Not only does it match its rivals in energy output, it also reduces the damage done to the world. The production of biodiesel from waste vegetable oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin vegetable oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. Recommendations: Further research should be done on the following areas: - Nowadays bio-diesel cost is 1.5 to 3 times higher than the fossil diesel cost because the largest share of production cost of bio-diesel is the feedstock cost. Therefore, biodiesel is not competitive to fossil diesel under current economic conditions, where the positive externalities, such as impacts on environment, employment, climate changes and trade balance are not reflected in the price mechanism. However, biodiesel can be made from other feedstocks of low cost oils and fats such as restaurant waste and animal fats that could be converted into biodiesel. The problem with processing these low-cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot be converted into biodiesel using an alkaline catalyst (Demirbas, 2003; Canakci and Van Gerpen, 2001). - Important operating disadvantages of bio-diesel in comparison with fossil diesel are cold start problems and the lower energy content. This increases fuel consumption when biodiesel is used (either in pure or in blended form) in comparison with application of pure fossil diesel, in proportion to the share of the bio-diesel content. Taking into account the higher production value of bio-diesel as compared to the 98 fossil diesel, this increase in fuel consumption raises in addition the overall cost of application of bio-diesel as an alternative to fossil diesel. - The competitiveness of bio-diesel relies on the prices of bio-mass feedstock and costs, linked to the conversion technology. Depending on the feedstock used, byproducts may have more or less relative importance. - Further experiments should be done in the lab such as producing the biodiesel from pure or waste vegetable oil and make it undergo under all the additional steps once the transestrification is completed as to get a biodiesel of high quality as for commercial biodiesel. Also, further fuel analytics should be done on biodiesel to get properties that match the standard values such as density, viscosity, heating value and oxidation stability. Moreover, further experiments of fuel analytics could be done to get other fuel properties as flash point, cloud point, cetane number, etc. and last but not least the further emission testing should be done on different engines using the biodiesel fuel to get results that show the reduction of emissions when using biodiesel as it said in theory. 99 Bibliography (1) http://www.biodieselbooklet.co.uk/biodiesel-wvo.html (2) http://www.tcbiodiesel.com/making-biodiesel-from-waste-vegetable-oil/ (3) http://www.marcussharpe.com/biodiesel.shtml (4) http://www.utahbiodieselsupply.com/whybiodiesel.php (5) http://oaithesis.eur.nl (6) http://www.bioenergywiki.net/What_is_bioenergy (7) http://renet-eu-india.com/energybio.php (8) http://www.sustainablebuild.co.uk/BioEnergy.html (9) Biomass resource facilities and biomass conversion processing for fuels and chemicals, AyhanDemirba s * P.K. 216, TR-61035-Trabzon, Turkey (10) http://www.windows2universe.org/earth/Water/co2_cycle.html (11) http://www.windows2universe.org (12) http://www.energyfuturecoalition.org/biofuels (13) http://www.ppvir.org/pdf (14) Political, economic and environmental impacts of biofuels: A review Ayhan Demirb (15) Biodiesel, a realistic fuel alternative for diesel engines- springer-2008.pdf (16) http://www.window.state.tx.us/specialrpt/energy/renewable/biodiesel.php (17) http://www.window.state.tx.us/specialrpt/energy/renewable/ethanol.php (18) http://news.mongabay.com (19) http://www.nrel.gov (20) http://www.bdpedia.com/biodiesel/char/char.html (21) www.wikipedia.org/wiki/Biodiesel#Biodiesel_feedstocks (22) http://www.ag.ndsu.edu/pubs/ageng/machine/ae1240w.htm (23) www.wikipedia.org/wiki/Biodiesel 100 (24) http://www.sciencedirect.com/.pdf Biodiesel from waste cooking oil via basecatalytic and supercritical methanol transesterification Ayhan Demirbas (25) http://www.uic.edu/ biodiesel1_module.pdf (26) http://www.biodiesel.org (27) http://www.biodiesel1_module.com/pdf (28) http://ftp.jrc.es/EURdoc/eur20279en.pdf (29) Biodiesel RME-Rechner Chemical Engineering department, HAW (30) The production of biodiesel from rapeseed oil experiment, Chemical Engineering department, university of applied science (HAW). (31) Thin layer chromatography device in the Lab of chemical engineering department in HAW (32) www. Berlin072-prestandarddinv51605.com/pdf (33) http://www.biodieselfillingstations.co.uk/approvals.htm (34) Kinematic Viscosity experiment, Mechanical Engineering department, University of Applied Science (HAW), Amberg, German (35) http://www.thefullwiki.org/Viscometer) (36) http://classle.net/bookpage/properties-biodiesel (37) http://en.wikipedia.org/wiki/Hydrometer (38) http://en.wikipedia.org/wiki/File:PycnometerEmpty.jpg (39) http://classle.net/bookpage/properties-biodiesel (40) Heating value experiment, Mechanical Engineering department, University of Applied Science (HAW), Amberg, Germany (41) http://en.wikipedia.org/wiki/Calorimeter (42) http://www.metrohm.com/com/downloads/OMS/oxidation_stability.pdf (43) http://www.springerlink.com/content (44) http://www.rsc.org/images (45) http://www.cecri.res.in/CIF/cif.htm (46) http://www.biofuelsb2b.com/useful (47) www.biofuels2b2.com (48) http://www.kubotaengine.com/products/05/d1105_e3_2.html 101 (49) http://www2.emersonprocess.com (50) http://www.quantitech.co.uk (51) http://www.brigon.de/englisch/smoke-tester.html 102 List of Figures Figure 4.3.1:The Carbon Cycle;The movement of Carbon dioxide through the atmosphere............................................................................................................................11 Figure 4.3.2: Biofuels and the carbon cycle..........................................................................13 Figure 5.1.1: Sources of main liquid biofuels for automobiles...............................................15 Figure 5.1.2: The world’s top ethanol and biodiesel producers in 2008 (REN21,2009).......16 Figure 5.1.3: Global ethanol and biodiesel production 2000-2008 with projection to 2015..17 Figure 5.1.4: Biodiesel Production Cycle……………………………………………………….17 Figure 5.1.5: Ethanol Production Cycle…………………………………………………………18 Figure 5.2: The World’s and EU’s biofuel consumption..........................................................21 Figure 6.2: Dr. Rudolf Diesel..................................................................................................23 Figure 6.7: Conversion of Vegetable Oil to Biodiesel............................................................29 Figure7.4: B100 emissions compared to petroleum diesel emissions by percentage.........39 Figure 7.5: A simple cycle of carbon dioxide of biodiesel and fossil fuel with different time frames..................................................................................................................................40 Figure 8.1: Price of fossil diesel (commercial use) Euro/l....................................................45 Figure 9.1: Biodiesel produced in the lab............................................................................49 Figure 6.2.1: Dr. Rudolf Diesel............................................................................................49 Figure 9.1.1.2: The filtration of 50 ml of rapeseed oil..........................................................50 Figure 9.1.2: Biodiesel RME Rechner.................................................................................51 Figure 9.1.4: Thin layer chromatography device in the Lab................................................52 Figure9.2.3: The Ubbelohde viscometer.............................................................................56 Figure9.2.4.1: Hydrometer..................................................................................................57 Figure 9.2.4.2: Pycnometer.................................................................................................58 Figure 9.2.5: Bomb Calorimeter..........................................................................................60 Figure 9.2.6: The Rancimat device......................................................................................61 Figure 9.2.6.1: The oxidation stability graph of rapeseed oil...............................................63 Figure 9.2.6.2: The oxidation stability graph of biodiesel (from gas station).......................63 Figure 9.2.6.3: The oxidation stability graph of biodiesel (produced in lab)........................64 103 Figure 9.2.6.4: The oxidation stability graph of diesel fuel..................................................64 Figure 9.3: CHNS-O Elemental Analyzer............................................................................66 Figure 9.5.1: Biodiesel from gas station..............................................................................76 Figure 9.5.2: Biodiesel produced in the lab.........................................................................76 Figure 9.6.1.1: Kubota diesel engine...................................................................................79 Figure 9.6.1.2: MLT 4 Gas analyzer....................................................................................80 Figure 9.6.1.3: Total hydrocarbon analyzer.........................................................................81 Figure 9.6.1.4: Smoke tester device....................................................................................82 Figure 9.6.2.1: Smoke / soot samples.................................................................................83 Figure 9.6.2.2: Densitometer (device for determining the smoke number).........................84 and the smoke scale Figure 9.6.4.1 : Resulted SO2 emissions for rapeseed oil, diesel and biodiesel................88 Figure 9.6.4.2: Resulted NOx emissions for rapeseed oil, diesel and biodiesel.................88 Figure 9.6.4.3: Resulted CO emissions for rapeseed oil, diesel and biodiesel...................89 Figure 9.6.4.4: Resulted O2 emissions for rapeseed oil, diesel and biodiesel....................89 Figure 9.6.4.5: Resulted CO2 emissions for rapeseed oil, diesel and biodiesel.................90 Figure 9.6.4.6: Resulted hydrocarbon emissions for rapeseed oil, diesel and biodiesel.....90 Figure 9.6.4.7: Resulted filter smoke number for rapeseed oil, diesel and biodiesel...........91 Figure 10.1: Biodiesel from gas station..................................................................................95 Figure 10.2: Biodiesel produced in the lab.............................................................................95 104 List of Tables Table 5.1: Major benefits of Biofuels...................................................................................14 Table 5.2: An Overview of the product biofuel, per generation type...................................20 Table 6.8: Comparison of properties of waste cooking oil, biodiesel from waste cooking oil and commercial diesel fuel..................................................................................................32 Table 7.2: Properties of Biodiesel prepared from vegetable oils.........................................36 Table 8.2.2: Bio-diesel cost production depending on rape-seed price in Euro/l................46 Table 9.2.2: Some properties of diesel and biodiesel standards…………………………...54 Table 9.2.3: Experimental results of kinematic viscosity for rapeseed oil, two types of biodiesel and diesel fuel......................................................................................................56 Table 9.2.4: Experimental results of Density for rapeseed oil, two types of biodiesel and diesel fuel............................................................................................................................58 Table 9.2.5: Experimental results of Lower heating value for rapeseed oil, two types of biodiesel and diesel fuel......................................................................................................60 Table 9.2.6: Experimental results of Oxidation stability for rapeseed oil, two types of biodiesel and diesel fuel.....................................................................................................................62 Table 9.3.1: Elementary analyzer results for biodiesel produced in lab..............................67 Table 9.3.2: Elementary analyzer results for diesel fuel and rapeseed oil..........................68 Table 9.3.3: Elementary analyzer results for biodiesel (gas station)...................................69 Table 9.4.1: Characteristic properties for Rapeseed 0il according to DIN 51 605 - German Rapeseed Oil Fuel Standard...............................................................................................70 Table 9.4.2: Characteristic properties for Rapeseed 0il according to experiments done in the Lab. of the FachHochSchule, Amberg 2010/2011..............................................................71 Table 9.4.3: Characteristic properties for Biodiesel according to European Standard EN 14214.............................................................................................................72 Table 9.4.4: Characteristic properties for two types of Biodiesel, one produced in the lab. of the Fachhochschule, Amberg 2010,/2011 and the other one was bought from the gas station..................................................................................................................................73 Table 9.4.5: Characteristic properties for Diesel according to the DIN EN 590 standards, July1999..............................................................................................................................74 Table 9.4.6: Characteristic properties for Diesel according to according to experiments done in the Lab. of the FachHochSchule, Amberg, 2010/2011……………...............................75 105 Table 9.6.3.1: Three different readings for the total hydrocarbons in three different times and three different readings for ash number for every fuel........................................................85 Table 9.6.3.3 Mean values of the resulted emissions for every fuel...................................86 Table 9.6.3.2: The values of cooling water temperature, the exhaust temperature, the mean values of the total hydrocarbons and the smoke number for every fuel………………….87 106 Appendix A: The experiment of biodiesel production from rapeseed oil, the experiments of Density, Kinematic viscosity, High calorific value and Oxidation stability experiments for fuel analytics of rapeseed oil. (These experiments were done also on Diesel and Biodiesel), the DIN 51605 of Rapeseed oil, 2005-06 and the DIN EN 590 for Diesel, July, 1999. A.1 The production of biodiesel from rapeseed oil experiment……………….108 A.2 Density experiment…………………………………………………………....110 A.3 Temperature corrector for Hydrometers table…………………………......111 A.4 Kinematic Viscosity Experiment……………………………………………..112 A.5 High heating value Experiment………………………………………….…..114 A.6 The oxidation stability Experiment……………………………………….....116 A.7 DIN 51605 of Rapeseed oil, 2005-06………………………………………119 A.8 DIN EN 590 for Diesel………………………………………………………..120 A.9 CHNS Elementary Analyzer………………………………………………....121 107 A.1 The production of biodiesel from rapeseed oil experiment 108 109 A.2 Density experiment 110 A.3 Temperature corrector for Hydrometers table A.4 Kinematic Viscosity Experiment 111 112 113 A.5 High heating value Experiment 114 115 A.6 The oxidation stability Experiment 116 117 118 A.7 DIN 51605 of Rapeseed oil, 2005-06 119 A.8 DIN EN 590 for Diesel 120 A.9 CHNS Elementary Analyzer 121 122 Appendix B :Specifications of equipment used for the emission testing experiment B.1 Specifications of Engine………………………………………………124 B.2 Specifications of Gas Analyzer………………………………………126 B.3 Specifications of Hydrocarbon analyzer…………………………….130 B.4 Specifications of Brigon smoke tester………………………………133 123 B.1 Specifications of Engine 124 125 B.2 Specifications of Gas Analyzer 126 127 128 129 B.3 Specifications of Hydrocarbon analyzer 130 131 132 B.4 Specifications of Brigon smoke tester 133
