Biofuels: A Review of Philippine Studies
by
Divine Grace M. Convento
Joel P. Abacan
Finesse M. Acio
A Research Report Submitted
to the School of Chemical Engineering and Chemistry
in Partial Fulfilment of the Requirements for the Degree
Bachelor of Science in Chemical Engineering
Mapúa Institute of Technology
July 2007
APPROVAL SHEET
This is to certify that we have supervised the preparation of and read the research report
prepared by Joel P. Abacan, Finesse M. Acio and Divine Grace M. Convento entitled
Biofuels: A Review of Philippine Studies and that the said research report has been
submitted for final examination by Oral Examination Commitee.
Flordeliza C. De Vera
Course Coordinator
Rhoda B. Leron
Research Adviser
As member of the Oral Examination Commitee, we certify, that we have examined this
research report, presented before the committee on July 11, 2007, and hereby recommend
that it be accepted as fulfilment of the research report requirement for the degree in Bachelor
of Science in Chemical Engineering.
Bonifacio T. Doma, Jr.
Panel Member 2
Jonathan L. Salvacion
Panel Member 1
Alvin R. Caparanga
Panel Member 3
This research report is hereby approved and accepted by the School of Chemical Engineering
and Chemistry as fulfilment of the research report requirement for the degree in Bachelor of
Science in Chemical Engineering.
Alvin R. Caparanga
Chair, Chemical Engineering
Luz L. Lozano
Dean, School of Chemical
Engineering and Chemistry
ii
ACKNOWLEDGEMENT
We would like to express our sincerest gratitude to our Almighty Father for leading us
throughout the course of completing this project. We also thank you Lord for the graces you
have granted us in constructing this paper. This work is a witness of God’s Love and Mercy.
With this we give back all the glory and praises to you, Almighty Father.
To Ms. Rhoda B. Leron, our thesis adviser, thank you very much for your unwavering
guidance and support throughout the completion of this project. We also thank you for
accompanying and assisting us in our literature search.
To Mr. Manuel R. De Guzman, our former research coordinator and adviser, thank you for
entrusting this research project to us.
To Dr. Rex B. Demafelis, lead convenor of the UPLB Alternative Energy RDE and
chairperson of the Department of Chemical Engineering in CEAT, thank you very much for
comprehensively discussing us the overview of your project and especially for the time you
spent for answering our questions.
To Dr. Raymond R. Tan, Senior Research Scientist at the Center for Engineering &
Sustainable Development Research and Director of the Engineering Graduate School of
DLSU-Manila, thank you very much for the informative discussion on bioethanol and the
resources that you gave us.
To Ms. Flordeliza Baustista, Ms. Rosario Lopez, Ms. Maria Comagon, and Ms. Adela
Dumalanta, DOST STII Librarians, thank you for assisting us in finding for the necessary
resources that we needed.
To Ms. Ruby De Guzman, Mr. Arnell Garcia, and Mr. Andy Urgado of Department of
Energy- Alternative Fuels Division, thank you for the resources and information that helped
us tracked the studies in biofuels.
To Ms. Divina Chingcuanco and Ms. Sherryl Vitales of Sustainable Energy Development
Program, thank you for the research articles and references that you gave us.
To Ms. Cleotilde A. Bulan of the Chemical and Mineral Division- Industrial Development
Institute of DOST, thank you for the research articles that you shared with us.
To Mr. Carlos P. Palad and Mr. Glenn Apostol of Chemrez Technologies, Inc, thank you
very much for the open discussion on biodiesel and for the suggestions that you imparted to
us.
To Mr. Felipe M. Argamosa of the Technological University of the Philippines, thank you
for accommodating us and for giving us the articles that we needed.
iii
To the Librarians of the Department of Environment and Natural Resources (DENR),
University of the Philippines-Los Baños (UPLB) Main Library, UPLB- College of
Engineering and Agro-industrial Technology (UPLB-CEAT) Library, National Institute of
Molecular Biology and Biotechnology (BIOTECH), Southeast Asian Regional Center for
Graduate Study and Research in Agriculture (SEARCA) of Southeast Asian Ministers of
Education Organization (SEAMEO), Philippine National Library, thank you very much for
assisting us in our literature search.
To the Philippine Fuel Ethanol Alliance, thank you for the informative resources in
bioethanol.
Finally and most importantly, to our beloved parents and relatives, thank you very much for
the moral and financial support that we needed to relieve the difficulties that we encountered
during the completion of our project. They all served as role-models and inspirations in our
daily walks of life.
Joel P. Abacan
Finesse M. Acio
Divine Grace M. Convento
iv
TABLE OF CONTENTS
TITLE PAGE
i
APPROVAL PAGE
ii
ACKNOWLEDGEMENT
iii
TABLE OF CONTENTS
v
LIST OF TABLES
vii
LIST OF FIGURES
viii
ABSTRACT
ix
Chapter 1:
INTRODUCTION
1
Chapter 2:
BIODIESEL
4
2.1 Biodiesel from Coconut Oil
4
2.1.1 Crude Coconut Oil
2.1.2 Thermal Cracking of Coconut Oil and Kolbe Electrolysis Process
2.1.3 Coconut Methyl Esters
2.1.3.1 Studies in Esterification Process
2.1.3.2 Engine Performances of Pure and Blended CME
2.1.3.3 Environmental Impacts of Coconut Biodiesel
2.1.3.4 Economics and Life-cycle Assessment of Biodiesels
5
6
7
13
13
15
16
2.2 Jatropha Biodiesel
17
2.3 Biodiesel from Other Feedstocks
19
2.4 Summary and Conclusions
22
Chapter 3: BIOETHANOL
26
3.1 Sources of Ethanol
26
3.2 Microorganisms Involved in Ethanol Production
32
3.2.1 Amylase-Producing Bacteria
3.2.2 Enzymes for Cellulose
3.2.3 Alcohol Producing Microorganisms
v
33
33
34
3.3 Studies in Ethanol Fermentation
3.3.1 Ethanol Production Using Different Substrates and Microorganisms
3.3.2 Non-Cooking Ethanol Fermentation
38
39
44
3.4 Ethanol Fermentation Systems
45
3.5 Separation and Purification Processes
47
3.6 Waste and Wastewater Management
47
3.7 Ethanol Used as Fuel
50
3.7.1 Ethanol as Gasoline Substitute and Additive
3.7.2 Ethanol as Diesel Substitute and Additive
51
55
3.8 Environmental Impacts of Ethanol Production and Application
57
3.9 Summary and Conclusions
59
Chapter 4: RECOMMENDATIONS
65
4. 1 Biodiesel
65
4.2 Bioethanol
67
REFERENCES
70
APPENDIX A
77
APPENDIX B
80
APPENDIX C
81
APPENDIX D
83
APPENDIX E
84
vi
LIST OF TABLES
TABLE 2.1: FUEL CHARACTERISTICS OF KOLBE ELECTROLYSIS PRODUCT
OF COCONUT FATTY ACIDS AND ACETIC ACIDS
TABLE 2.2: TEST RESULTS FROM ARIDA ET AL.’S EXPERIMENT
TABLE 2.3: PHILIPPINE BIODIESEL STANDARD SPECIFICATIONS
TABLE 3.1: YIELDS OF BIOMASS AND ETHANOL FOR
SOME AGRICULTURAL CROPS
TABLE 3.2: PRODUCTION AND OIL EQUIVALENT
OF AGRO-FORESTRY WASTES
TABLE 3.3: ALCOHOL PRODUCTION BY S. CEREVISIAE TJ-1
AND ITS DERIVATIVES
TABLE 3.4: ALCOHOL PRODUCTION YEAST STRAINS IN SHAKE-FLASK
CULTURE AT DIFFERENT TEMPERATURES
TABLE 3.5: COMPARISON OF VARIOUS FERMENTATION SYSTEMS
WITH Z. MOBILIS (PH=5.0, T=30-35OC)
TABLE 3.6: PROPERTIES OF BIOETHANOL AND UNLEADED GASOLINE
TABLE 3.7: EFFECT OF AIR BLENDING ON AIR EMISSIONS
RELATIVE TO GASOLINE BASELINE
vii
8
10
11
27
31
36
38
46
51
59
LIST OF FIGURES
FIGURE 2.1: THE TRANSESTERIFICATION REACTION
4
FIGURE 3.1: ETHANOL SYNTHESIS
FIGURE 3.2: ALCOHOL PRODUCTION FROM NIPA SAP
39
42
viii
ABSTRACT
Efforts have been made in many countries, like Brazil, India and US, to search for
suitable alternative fuels. Likewise, several researches had long been conducted in the
Philippines in order to resolve pollution and the depletion of oil reserves. In 2006, the
Biofuel Act was implemented as part of the President’s energy independence program.
However, the success of utilizing indigenous and renewable fuels can be hindered with
regard to its reliability, which arises mainly from the issue as to what extent of improvement,
must be undertaken and what cost-effective technologies must be used in both biodiesel and
bioethanol applications. In this study, an in-depth review of literatures/studies done in the
Philippines on biofuels (bioethanol and biodiesel) was conducted. Significantly,
product/blending, technological and scientific as well as their sustainable (social, economic
and environmental) aspects were presented. Topics for research were also identified and
listed at the end of this paper. It will serve as a good reference tool for the succeeding studies
on biofuels to the engineer’s field. Finally, this study will help in the planning of future
research activities and the prevention of duplication of literatures in the country as well as
better understanding of biofuel characteristics and applications. The identified research topics
in ethanol and biodiesel were themed as follows: a) potential feedstocks and productivity
enhancements, b) modification of trans-esterification and its technological developments, c)
oil extraction and refining techniques, d) genetic modifications of oil plant seeds, e) blending
variations of different oils with diesel, f) glycerol-based process design, g) selection and
genetic modifications in microbial fermentation, h) cellulosic fermentation, i) design of
wastewater treatment, and j) cost-effective separation-purification technology.
Keywords: biofuel, biodiesel, bioethanol, transesterification, ethanol fermentation
ix
Chapter 1
INTRODUCTION
The increasing prices of petroleum fuels and decreasing availability of conventional
and non-renewable energy sources gave way to the development and production of
alternative fuels such as biofuels.
Biofuel is a generic term for transport fuel that can be produced from renewable
material of plant or animal origin and are utilized as substitutes or extender for fossil fuels.
The Republic Act 9367 (Biofuels Act of 2006) refers to fuels “made from biomass and
primarily used for motive, thermal and power generation, with quality specifications in
accordance with the Philippine National Standards (PNS).” These chiefly refer to biodiesel,
fuel made from plant oils, and bioethanol, fuel from starchy agricultural crops/grains or
sugarcane. Both are used as source of energy.
Biofuel have received considerable attention. In the Philippines, the sudden turn of
fuel trend into biofuels was greatly influenced by the newly enacted Biofuels Act of 2006.
This act mandates the use of biofuels as fuel blends. The mandatory use of biofuels states
that all liquid fuels for motors and engines sold in the Philippines shall contain locallysourced biofuels components as follows: Within three months from the effectivity of this Act,
a minimum of one percent (1%) biodiesel by volume shall be blended into all diesel engine
fuels sold in the country; and within two years from the effectivity of this Act, at least five
percent (5%) bioethanol shall comprise the annual total volume of gasoline fuel actually sold
and distributed by each and every oil company in the country. Provided, that these biofuel
properties conform with the Philippine National Standards.
1
2
In pursuant to this act the Philippine government established a biofuel program
which envisions to reduce the Philippine dependence on imported crude, to increase
economic activity and employment in the countryside and to cut down on the country’s
greenhouse gas emission level, thus allowing it to meet global environmental standards on air
pollution. Besides ensuring the Philippine compliance with environmental standards, the
biofuel mandate would help the country reduce its purchases of costly imported crude that
can promote energy security and economic stability. The act also encouraged researchers in
developing and utilizing indigenous renewable and sustainably-sourced clean energy sources
in biofuel production.
Research and development in biofuels to supplement or substitute petroleum fuels in
the Philippines focus on these two major classification, the biodiesel and bioethanol.
Bioethanol is an alcohol made from sugar, starch and products containing sugars and starches
through a process of fermentation and distillation, and used as a substitute or supplement for
gasoline. Biodiesel, on the otherhand, can be produced from any plant oils or animal’s fats
that are chemically reacted to be converted to esters and used as a substitute or supplement
for petroleum diesel. Technically, bioethanol is defined as ethyl alcohol derived from
agricultural crops or sugars for use in gasoline engine while biodiesel is defined as
monoalkyl esters derived from agricultural oils for use in diesel engine. The Philippines
commonly utilized sugarcane for bioethanol while coconut oil and jatropha oil for biodiesel.
Many biofuels were already developed and used in many parts of the world. A lot
of researches and attempts in the development and improvement of biofuels in the
Philippines were done using raw materials that are feasible and available in the country.
Studies were conducted with the use of coconut oil and jatropha oil and other oil materials
3
for biodiesel production. Also, numerous studies were conducted in producing bioethanol
from different locally available biomass for gasoline-blend applications. Research has to be
continued to further improve and establish the biofuel research in the Philippines. An
extensive literature review is essential and an in-depth analysis is needed to further improve
the biofuels research in the Philippines.
A number of literatures have shown the feasibility and advantages of using biofuels
whether blended with the conventional fuel or the pure biofuel. These studies helped in the
establishment of information about the utilization of biofuel as alternative fuel.
The objectives of this study are to conduct a comprehensive literature review of the
studies done in the Philippines on biofuels: biodiesel and bioethanol, and to identify possible
topics for research on this area.
This study focuses on the progress of biofuel researches in the Philippines. This
paper will include the studies in biofuels in the Philippines: coco biodiesel and jatropha
biodiesel, and bioethanol. This study will cover published articles in the Philippines. It will
also cover and review unpublished articles from various institutions in Metro Manila and
other nearby provinces. The study will also cover published articles around the country.
Other alternative energy sources such as biogas will not be covered by this study.
Moreover, this study will provide necessary information and will serve as a helpful
tool for advanced researches in biofuels. This will also serve as a good reference to further
improve the biofuel studies in the Philippines.
Chapter 2
BIODIESEL
Biodiesel is an alternative diesel fuel derived from transesterification of vegetable
oils with simple alcohols to give the corresponding mono-alkyl esters. Fatty esters from
vegetable oils and fats have been proven to be an effective substitute to diesel fuels. In
general, the transesterification of vegetable oil proceeds as follows:
Figure 2.1. The Transesterification Reaction
2.1 Biodiesel from Coconut Oil
Early researches on renewable liquid fuels focus on the use of raw vegetable oil as
fuel substitute or supplement to run diesel engines. Biodiesel can be obtained from tree
crops, such as palms, coconuts, and olives (Cadenas and Cabezudo, 1998). This creates a
great potential in the Philippines since it can supply up to 60 percent of the world’s coconut
market (Carandang, 2002). Studies show that coconut oil has a potential of being a biodiesel.
4
5
2.1.1 Crude Coconut Oil
Domingo and Cruz (1982) studied the fuel adapted as a substitute for the diesel
engine operation. The fuel adapted as a substitute for diesel in the operation of diesel engine
comprising of producer gas and crude coconut oil. The objective of the study was to provide
a fuel for diesel engines wherein pure crude coconut oil is being utilized, and to provide a
fuel for diesel engines wherein combination of producer gas and crude coconut oil is used.
After experiments and trial tests were conducted, the study proved that technical feasibilities
of adapting pure crude coconut oil and producer gas with certain percentage of diesel fuel
and/or coconut oil as igniter could be used as fuel for the operation of diesel engines in
general without changing or altering the internal parts of the engines.
Likewise, Dela Paz (1983) investigated the efficiency of crude coconut oil.
However, an old-fashioned yet cost-effective approach of producing coconut oil was applied
and the steps are as follows: (a) dehydrating the coconut oil emulsion, freshly pressed from
the coconut meat, to remove the moisture content while scraping the formed protein solids
(latik); (b) the coconut oil is then mixed with ordinary diesel fuel; (c) filtering the mixture;
(d) polishing by passing it again through a super fine filter.
The process from the above claim contains 25% by volume coconut oil and 75% by
volume of ordinary diesel fuel. Road tests was to analyze the quality of Dela Paz’ invention
of coconut oil and diesel fuel blend which he termed as “coco-diesel” resulted to a substantial
similarity with the road test of an ordinary diesel fuel. It was noted that while the exhaust
fume of the diesel engine using an ordinary diesel fuel is black, the exhaust fume of the
engine using coco-diesel is clear and white. Further, buses operated with a 30% coconut oil
6
blend with petroleum diesel fuel was reported to have clogged fuel filters due to the
formation of slimes in the fuel from the presence of water.
Preliminary use of vegetable oils, such as coconut oil to substitute diesel fuel
however, described them to be good only for short term engine use (Arida, 1984). Prolonged
use even if the vegetable oil were mixed with diesel fuel, caused several problems, one of
which was extensive clogging fuel lines, that eventually prevented the engine to operate. All
of these problems result from the highly viscosity, low volatility and polymerization
tendency of the vegetable oil (Sumera and Sadain, 1990). To avoid these problems, it was
suggested to modify the structure of the vegetable oil and improve its physico-chemical
properties to meet the specification of current diesel engines.
2.1.2 Thermal Cracking of Coconut Oil and Kolbe Electrolysis Process
Dela Gente (1983) presented the process of manufacturing a diesel fuel substitute
from coconut oil and other vegetable oil wherein the crude coconut oil, palm nut and any
vegetable oil is processed using the thermal cracking apparatus and then refined using an
absorbing unit. The resulting product from the said invention can be used as fuel for all types
of diesel engine. The resulting cracked coconut oil when used as diesel fuel on an Isuzu 240
Power Public Utility vehicle and AFP Cargo truck was observed to perform satisfactorily
even without altering the engine. Dela Gente (1983) also observed that there was complete
combustion of fuel, minimal pollution and the engine delivered more power when the diesel
fuel substitute was utilized.
Diesel fuel by Kolbe electrolysis of potassium salts of coconut fatty acids and acetic
acids was studied by Sumera and Sadain (1990). This method leads to the production of
7
liquid straight chain alkanes that include cetane and its homologues. The study proposed a
method of transforming coconut oil to a form acceptable as diesel fuel substitute, by Kolbe
electrolysis of potassium salts of coconut fatty acids and acetic acids. The Kolbe electrolysis
of potassium salts of coconut fatty acids and acetic acid using platinum electrodes produced a
clear liquid product (58% theoretical yield) with very good diesel-fuel properties. Analysis
of the liquid product showed that it contained 83% straight chain hydrocarbons, by gas
chromatography composed of 0.5% decane, 34.6% dodecane, 22.5% tetradecane, 14.2%
hexadecane, 17.0% octadecane, 2.1% eicosane, 6.5% docosane, and 3.0% tetracosane. The
physico-chemical properties of the products revealed its potential as a better diesel substitute
than the known coconut oil substitute. Table 2.1 presented the fuel characteristics of Kolbe
Electrolysis product of coconut fatty acids and acetic acids.
The chemical analysis of the electrolytic product suggests that very good diesel-like
properties are expected due to its high content of straight chain alkanes, one of which is
cetane or hexadecane used as diesel reference with the highest cetane number and index of
100. The study further recommended an engine test to be performed to verify its fuel
potential in various manner of its application.
2.1.3 Coconut Methyl Esters
One modification made on the chemical structure of the vegetable oil is by
transforming it into fatty esters (Arida, 1984; Banzon, 1980; Ong et al., 1984).
The
transformation is done through transesterification of the vegetable oil with ethanol or
methanol in the presence of an acid or base catalyst. It was reported that the properties of the
8
fatty ester derivatives meet the requirements of the current diesel engines and are therefore
better substitute than the original or raw vegetable oil.
Table 2.1. Fuel Characteristics of Kolbe Electrolysis Product
of Coconut Fatty Acids and Acetic Acids
Number
Test Conducted
Test Method
Test Result
o
1
Density at 15 C
ASTM D 1298
0.8062
2
Color
light yellow
3
Odor
pleasant
o
4
Viscosity (Cs) at 30 C
Falling ball type
2.57
(Cp)
1.97
5
Distillation
ASTM D 86
o
I.B.P. C
88
o
10% C
120
o
20% C
230
o
30% C
234
o
40% C
244
o
50% C
256
o
60% C
272
o
70% C
290
o
80% C
312
o
90% C
350
F.B.P.
355
6
Cetane Index
ASTM D 976
60.5
Gross Heat of
7
ASTM D 240
47.56
Combustion MJ/kg
8
Flash Point
ASTM D 92
98 oC
Conradson Carbon
9
ASTM D 189
0.1
Residue % mass
10
Freezing Point
-12 oC
11
Refractive Index
1.43328
Pryde (1981) suggested the modification of vegetable oils by transesterification,
microemulsion formation and use of viscosity reducers to overcome the problems on using it
9
as fuel. Transesterification was considered to be the most suitable modification because
esters approach the viscosity of diesel fuel.
In the kinetic study of Banzon (1953, 1980) and the laboratory analysis conducted
by Aliwalas et al. (1969) with Catanaoan’s investigation on (unpublished, NIST) pilot plant
scale production, it was found that methanolysis is a convenient and more cheaper process
than ethanolysis because the reaction is very rapid in homogenous systems in the presence of
an alkali catalyst.
It was the group of Arida (1981, 1984) which determined the conditions for the
production and development of a diesel fuel substitute suitable for internal combustion
engines. Their invention can accurately be described thru the following steps: esterifying one
molecular proportion of coconut oil preheated to 60-65°C with 9.0 moles of methanol with
10-15% excess in a glascote reactor; adding immediately to the mixture in two stages, 0.30.6% NaOH which is pre-dissolved in alcohol; agitating continuously the mixture for about
40-60 minutes; allowing the reaction product to settle; separating the glycerine by-product
from the formed mixed methyl esters; heating the mixed methyl esters to distil off the excess
methanol; heating the alcohol-free esters to 70-90°C and washing with water 3-4 times or as
necessary; heating the washed mixed methyl esters to remove the moisture; fractionating the
moisture-free mixed methyl esters in a fractional distillation apparatus under a vacuum of 2530 inches Hg to separate the lower boiling fractions from the higher boiling fraction;
collecting separately or collectively the different lower boiling fractions and the higher
boiling fraction which is the residual product and finally, adding to the residual product other
lower boiling distillate fractions.
10
The properties of the said product are summarized in Table 2.2. The said
classification for coco-methyl ester is suitable for engines involving frequent and wide
variations of load speed.
Table 2.2. Test Results from Arida et al.’s experiment
Tests and Methods
API gravity
Flash point
Cetane index
high heating value
Viscosity
ASTM classification
Specifications
28-32
280-330
38-45
Remarks
heavy crude oil
comparative with diesel
limit for a diesel fuel = 40
16000-17500 BTU/lb
• SSU 40-55
(4.12-8.41 cSt at room
temperature)
• SSU 36-48
(2.97-6.40cSt at 100°C)
Grade 2D
SSU-Seconds
Saybolts
Universal
Bulan (unpublished) listed the critical key points for CME as fuel quality which
includes; Flash point whose limits is set at 100 ˚C to ensure the removal of excess methanol
used during the manufacturing process. Presence of residual methanol even at small amount
reduces flash point. It can also affect fuel pumps and seals and can result to poor combustion.
Moreover, Sulfated Ash ensures the removal of catalyst. High level catalyst in the fuel can
result in injector deposits or filter plugging, Acid Number limits to 0.5 maximum. Higher
than the set limit may cause fuel system deposits and reduce the life of the fuel pumps and
filters, and Free and Total Glycerine Number which measure the degree of conversion of oil
into ester. Furthermore, if the value of Free and Total Glycerine Number is too high, fuel
gumming and engine fouling will occur. The fatty acid alkyl ester produce can only be
termed as biodiesel when it significantly conforms to the Philippine National Standard for
biodiesel. These standards are presented in Table 2.3.
11
Table 2.3. Philippine Biodiesel Standard Specifications
Properties
Philippines Standard
DPNS/DOE QS 002
2007
Properties
Flash Point
100.0 C, min
Distillation
AET
90%
recovered
Kinematic
viscosity
Sulfur Content
Carbon
Residue
Cetane
Number
Sulfated Ash
Content
Water Content
and Sediment
2.0-4.5 mm2/s
Iodine Number
o
0.050@mass, max
0.050% mass, max
(100%spl.)
51 min
0.020 % m/m, max
0.050% vol., max
Water Content
0.050% vol., max
Copper Strip
Corrosion 3h
50oC
No. 1, max
Acid Number
0.50 mg KOH/g, max
Glycerine
Free
Glycerine
Total
Glycerine
Phosphorous
Content
Cloud Point
0.02% mass, max
0.24% mass, max
0.001% mass, max
Report oC,
Density
Philippines Standard
DPNS/DOE QS 002
2007
360oC, max
0.86-0.90 kg/L
CFPP
Total
Contamination
Oxidation
Stability
Total
Ester
Content
Methyl
Laurate,
%
mass
6 H min.
96.50% min.
45 min.
LinoleinacidMethylester
Alkali Content
(Na+K)
Magnesium
and Calcium
Methanol
Content
5 mg/kg
5mg/kg
0.02 % m/m, max
Glyceride
Mono
Glyceride
Di Glyceride
Tri Glyceride
0.8% m/m, max
0.2% m/m, max
0.2% m/m, max
12
Chemrez Technologies is among the pioneering company in CME production in the
Philippines. The company produces 250 metric tons of CME/ day. Their product, BioActiv
BD-100, can be used as diesel fuel enhancer which claims to boosts cetane number; reduce
emission of smoke (particulate matter), carbon monoxide, hydrocarbons, sulfur and nitrogen
oxides; and impart lubricity and solvency. The plant utilizes food-grade coconut oil as raw
input. The coconut oil undergoes transesterification which produces CME that contains
impurities. The plant process has a 96.5% conversion. Impurities are composed of residual
catalyst, soap, glycerine, residual water and methanol. The CME containing impurities are
purified while recovering the impurities. The company practices a “zero-discharge”
operation, which means all by-products are recovered and some are recycled. Among the byproducts recovered is glycerine which the company recovers and purify. The conversion of
coconut oil into CME accompanies the production of glycerol at about 9-10% of the product.
Mr. Glenn Apostol, chemist of Chemrez Technologies, recommends to research for the
conversion of glycerol into a more valuable product because the increased of production and
demand for CME will also yield an increase in glycerol surplus. He also added that another
point of research would be in the improvement of transesterification process of oil that will
give good quality biodiesel with lower quality of oil input to minimize the cost of raw
materials. Mr. Carlos P. Palad, Public Affairs Officer of Chemrez Technologies, stressed out
that the supply of coconut for biodiesel production is not sufficient for higher CME blending
Thus, he suggested to find for other suitable feedstock to diversify source and increase the
productivity that will eventually make biodiesel more economical and anticipate the increase
in demand. He also emphasized to study the blending of different biodiesel, like blending of
jatropha biodiesel and CME, to enhance biodiesel properties.
13
2.1.3.1 Studies in Esterification Process
A thesis proposal by Co (2007) that has a general objectives to design and to
operate a flow reactor which will produce fatty acid methyl esters from coconut oil with the
use of an anionic ion exchange resin catalyst, to determine the effect of specified flow
parameters on the yield, and to determine some of the properties of the biodiesel produced
with the ion exchange resin as the catalyst was currently being studied.
Another thesis proposal (Diamante et al., 2007) has a primary objective of
evaluating strong base anion exchange resins as a substitute for the catalyst in the
transesterification process of coconut oil by comparing the biodiesel product using the
conventional alkaline (NaOH) catalyst was also an on-going research.
2.1.3.2 Engine Performances of Pure and Blended CME
A study regarding the use of 100% CME as diesel substitute was conducted by
Carandang et al. in 1991. The 100%CME as diesel fuel was used for running an Asian Utility
Vehicle equipped with an ISUZU C-240 diesel engine for 25,000 kilometers. Chassis
dynamometer tests revealed an average 6% difference in thermal efficiency in favour of
diesel at horsepower settings of 5, 10, 15, 20, and 25, and speed of 60 kilometers per hour.
Fuel consumption index showed a 12%-16% advantage for diesel which was attributed to the
lower heating value of CME. Exhaust gas analyses showed 16% lower carbon monoxide
emission for CME, making it less polluting and more earth-friendly than diesel. Studies
regarding the optimum blend of CME to diesel fuels were also conducted.
14
The results of the study showed that there is a reduction of engine torque when the
diesel fuel is blended with CME. Low blending of CME (1% to 5% blend) has reduced the
torque of the engine by an average of 25%. Furthermore, a higher blend (10% to 20%) also
shows a reduction of 25%. It is therefore interesting to note that the reduction of it is almost
the same for a blend of 1%-20% while pure CME registers the highest torque reduction.
There is also a reduction in the NOx emission when the diesel fuel is blended with CME.
Low blend (1% to 5%) has already achieved a significant reduction of 74% and higher blend
(10% to 20%) has an average reduction of 84% which shows that there is an additional
reduction of 10% in smoke density for a higher CME blend. The pure CME has the highest
smoke density reduction of 93% (Yoshida et al., 2004). In contrast with the latter study from
Carandang et al. (1991), the study of Yoshida et al. (2004) showed that there is an increase in
CO as the blend of CME is increased. This study also showed that the most technically and
economically viable blend is the 1% because it has achieved a significant reduction in
emission without much increase on the price of diesel.
An important quality as enumerated by Arida is that it does not cause the engine to
overheat readily. Engines run on continuously on coco-diesel become as hot as 140°F far
lower than the 180°F of engine run on regular diesel fuel (Reyes, late 1970’s). Furthermore,
performance tests done using Mercedes Benz and jeep done by Arida et al. (1981, 1984)
were observed to deliver more power, less pollution and complete combustion although there
is also a need to test the prolonged use on the automotive engine and under all normal
conditions.
The results of Ibarra Cruz’ experiments regarding the thermal efficiency of coconut
oil as a diesel fuel was also mentioned from Cook (1983). In Cruz’ seventy five experimental
15
runs of ASTM-CFR stationary diesel engine and DUCATI IS-11 single cylinder diesel
engine (motorboat engines) conducted, the thermal efficiency with crude coconut oil was
3.33% with an average indicated horsepower of 6.83Hp which is lesser compared to a
thermal efficiency of 32.4% and indicated horsepower of 6.84Hp with petroleum diesel fuel.
Moreover, the thermal efficiencies using an Isuzu diesel engine of a passenger jeep was 11.3
and 12.1 kilometers per kilocalorie for coconut oil and petroleum diesel fuel respectively.
However, this product was reported to solidify overnight during cold climates which can
affect the combustion of the engine.
2.1.3.3 Environmental Impacts of Coconut Biodiesel
Pascual and Tan (2004) studied the quantitative assessment of the total
environmental impacts from emissions and energy consumption of coconut biodiesel and
petroleum or conventional diesel from the raw materials to the final use using environmental
life cycle assessment (LCA). The result of the life cycle assessment for coconut biodiesel
and diesel showed that the use of biodiesel in the Philippines can be applicable. Although,
the use of coconut residues for power cogeneration slightly increases some of the emissions
such as CO, NOx, and PM10, still it appears that the total impacts from emissions and energy
consumption are lower for both the automotive and industrial application.
Based on sulfur levels of 0.036% in mineral diesel and 0.01% in biodiesel, 10%
substitution should reduce total tailpipe sulfur emissions by 226 tons/yr (Tan et al., 2002).
16
2.1.3.4 Economics and Life-cycle Assessment of Biodiesels
Arida et al. (1981, 1984) studied and established the economics of the process and
the product. However, comprehensive feasibility study on the by-products of the
esterification process such as the various lower boiling methyl esters and glycerine was not
included. Based on the pre-economic feasibility study in De La Salle, it was generalized that
their investigation has been found to have a high economic potential as far as the financial
aspects of their study is concerned. Finally, they suggested that standardization of the process
either continuous or semi-continuously for possible large-scale production. Afterwards, Tan
et al. (2002) assessed some of the costs and benefits of a large-scale liquid biofuels program,
given the resource and technology constraints in the Philippines. Given the area of
agricultural land available, using 10% substitution limit of coconut biodiesel implies that it is
best utilized as a fuel additive or extender. Furthermore, carbon balance benefits are assessed
revealing potential annual CO2 reduction of 2.15-2.735 × 10 6 tons for 10% biodiesel
substitution.
Using the spreadsheet methods similar to Walsh (1996), Fujino (1999), and
Yamamoto (1999), they were able to project that higher rates of biodiesel production and
substitution can be made possible through the following measures: improvement of
agricultural yields of coconut through improved irrigation, genetic engineering, etc.;
conversion of additional non-agricultural land into sustainable energy farms; and utilization
of alternative feedstocks such as algae oils or waste grease (Klass, 1998).
Finally, with regard to land requirements, the 10% substitution for biodiesel
production requires 2.39 × 10 6 hectares (ha ) , whereas for 20% requires 4.78 × 10 6 ha , and
30% needs 7.17 × 10 6 ha . Thus, the current available coconut land was found to be sufficient
17
only in meeting about 10% of the projected diesel demand for the year 2004, provided that
earnings from the export of coconut oil are sacrificed.
2.2. Jatropha Biodiesel
The current price of coconut methyl ester (CME) is higher compared to petroleum
diesel. In view of high prevailing price of CME, it may not be possible to promote it
commercially. Therefore, some alternative feedstocks need to be identified. One of the
alternative feedstock that research eyed through was Jatropha curcas.
Jatropha curcas or “tuba-tuba” is being studied by the government to ensure
sustainability of the biodiesel program. Jatropha curcas is a non-edible plant that grows
mostly in tropical countries like the Philippines. Its seeds yield an annual equivalent of 0.75
to 2 tons of biodiesel per hectare. Its benefits are similar to coco-biodiesel to some extent but
its difference to it is that jatropha biodiesel include the reduction of greenhouse gas
emissions. Besides, local production of jatropha is also practical because as a non-food crop,
it will not compete with food supply demands. Moreover, it is resistant to drought and can
easily be propagated. Production of seeds starts within 14 months but reaches its maximum
productivity level after 4-5 years.
The feasibility study of using Jatropha as a feedstock for biofuel production was
analyzed by Parkash Kumar and M. Paramathma (2006). Some of the advantages of using
Jatropha curcas to be promoted in large scale production are the following: it can thrive on
any type of soil, needs minimal input or management, less incidences of pests and diseases,
not browsed by cattle or sheep, can survive under drought, easy propagation by seed/cutting,
rapid growth, lesser gestation period, and high yield with 30% oil in seed.
18
The Philippine National Oil Co.-Alternative Fuels Corp. (PNOC-AFC) tapped the
University of the Philippines at Los Banos (UPLB) to conduct an integrated Research and
Development program on Jatropha as feedstock for the production of biodiesel. The research
project headed by Rex Demafelis covers studies on germplasm management, varietal
improvement, seed technology, pest and disease management, enzymatic extraction and
transesterification, and waste management and byproduct utilization.
Jatropha oil must be extracted from the seeds. The team used three different
methods of extracting the oil from the seeds of Jatropha: mechanical (by expelling), chemical
(by solvent), and by enzymatic extraction. Comparative analysis between the three methods
was also conducted. Mechanical extraction involves crushing the Jatropha seeds under great
pressure to separate the oil from the oil seed. This process recovers up to 80% of the seed oil
content. The rest of the oil in the seed may then be recovered by chemical extraction. After
the oil was extracted, the oil must be refined to remove the impurities that may affect when it
will be esterified to produce the biodiesel. Such method of refining Jatropha oil includes
degumming.
For the transesterification process, they also used different methods and
combinations like: acid catalyzed esterification; alkali-catalyzed esterification using KOH
and methanol, KOH and ethanol, NaOH and methanol, and NaOH and ethanol; enzymatic
esterification; etc. (specific methods were not stated due to confidentiality of the project) and
the comparative analysis is currently on-going.
The purity of the produced Jatropha methyl ester (JME) has an average of 99.6 %
purity, surpassing the 96.5% purity requirement of the proposed PNS Specifications
presented in Table 3. Initial analyses of the fatty acid methyl ester (FAME) parameters to
19
determine the quality of Jatropha biodiesel were also conducted. Jatropha oil has a higher
unsaturated fatty acid which will affect the stability of the biodiesel. But according to
Demafelis, the produced Jatropha biodiesel has sterol which may serve as an anti-oxidant and
may protect the unsaturated fatty acid from oxidation, hence, making it stable. All of the
other quality parameters were scheduled to be tested to check for the compliance for the
biodiesel (fatty acid methyl ester) quality parameters as set by the Philippine National
Standards (PNS).
The study on the Jatropha biodiesel was extensively investigated by the group of
researchers at UPLB. As recommended by Demafelis, a possible research topic for the
biodiesel industry is to search another feedstock for biodiesel production.
He also
recommended to study the potential of bani and hanga as feedstock in biodiesel production.
Demafelis also suggested to study genetic modification of jatropha in improving its
productivity. He also recommended doing research in glycerol purification. Glycerol is a byproduct in the biofuel production.
2.3 Biodiesel from Other Feedstocks
Biodiesel can be produced from the transesterification of vegetable oil with an acid
or base catalyst. Vegetable oil can be obtained from nuts, seeds and plant materials
containing fatty acids. Appendix A summarizes the potential sources of oil for biodiesel
production.
The study performed by Bathan (2000) presented the possibility of using oil from
Pili shin pulp as an alternative fuel. In this study, oil was extracted from the pili shin pulp by
solvent extraction using hexane and solvent mixtures. It was deduced from the experiment
20
that hexane is a more effective solvent in the extraction of oil and that the amount of solvent
used, number of siphoning, and extraction time have significant effect on the amount of oil
extracted. Increasing the amount of solvent used using the shaking method increased the
amount of oil extracted. Further, the length of extraction time is determined to be dependent
on the siphoning rate using the Soxhlet Extraction Inoculum. Bathan (2000) also determined
that the increase in the number of siphoning and with a longer extraction time the amount of
oil extracted also increases. Also, it was concluded that varying the size of the particle used
in extraction does not affect extraction. The values that will yield the optimum amount of oil
at 37.98% are: 1:6 ratio of shin pulp to solvent, 0.0833 cm particle size, and 90 minutes
extraction time of the Soxhlet Extraction method. The physico-chemical characteristics of the
extracted oil have significant deviation from the literature values except for the specific
gravity and color appearance. The oil have a lower free fatty acid (17.8% w/w oleic) and an
Iodine value of 68.6g/100g but contains high peroxide value at 214mg/kg. The fatty acids
present in the oil are caprylic, lauric, linoleic acids. The heating value of the extracted oil is
calculated to be equal to 9,693.38 cal/g, which is comparable to the heating value of diesel
and bunker fuel. The oil produced was not converted into a biodiesel. Further study on the
properties of the biodiesel that will be produced using the oil extracted from pili shin is
needed to evaluate the viability of using it as biodiesel.
Studies on the conversion of soybean oil as biodiesel were also conducted.
Gosiengfiao (2003) were able to produced biodiesel from the alkali catalyzed
transesterification of soybean oil with NaOH as catalyst and methanol. In this study, they
determined the effects of soaking time and seed-to-solvent ratio on the yield of oil extraction.
The results obtained in this study showed that the highest yield of soybean oil that can be
21
extracted using hexane was obtained at 25 hours soaking time. It was determined that the
influence of soaking time on the yield has a 5% level of significance. The oil yield at
different seed-to-solvent ratio (w/v) of 1:4, 1:6, and 1:8 were 29%, 41.6% and 42%,
respectively which shows that highest yield can be obtained at a 1:6 seed-to-solvent ratio.
Analysis of the variance at 1:4 and 1:6 are significantly different at 5% level of significance.
The biodiesel produced from 1:3 ratio of methanol and oil with 3.5g of NaOH as catalyst has
a light yellow color. The product properties were determined. Analysis showed that it has a
specific gravity of 0.8841, kinematic viscosity of 4.01 cSt at 40 oC, 0.20% volume of H2O,
and a cetane index of 41. These values fell within the theoretical range except for the cetane
index but it also has a close physical characteristic with commercially available fuel.
Gosiengfiao (2003) recommend to further conduct studies on how to increase the cetane
number of the biodiesel produced.
Another study in the conversion of soybean oil was conducted by Bandapatan
(2003). The study applies the enzymatic extraction of soybean oil using UPLB BIOTECHproduced cellulase and protease. The experiment revealed that oil yield increases with
reaction time. A bell-shaped plot was also obtained showing the effect of pH on the yield
indicating that oil yield increased until it decreased after an optimum pH of 4.5 was reached.
The use of combination of cellulose and protease mixed enzyme systems gives high oil
yields. The enzymatic extraction of soybean oil showed that an enzyme mixture of 0.5%
(w/w) each of cellulase and protease at pH 4.5 and temperature of 30oC the most effective
extraction with an average oil yield of 6.2 % can be obtained. The biodiesel was produced
with a 1:6 ratio of oil to methanol and 0.5% (w/w) NaOH as catalyst at temperature range of
55-60oC. The biodiesel produced is cloudy, light yellow liquid with a kinematic viscosity of
22
5.11cSt, specific gravity of 0.8866, flash point of 65oC and 0.6% water content. The specific
gravity and kinematic viscosity fell on the range of specified values while the flash point and
water content of sample have unsatisfactory results. Bandapatan (2003) recommends the use
of other enzymes such as pectinase, hemicelluloses, and lignase to further improve the results
since the cell wall of soybean may not be composed of cellulose and protein only. Another
point of interest that can further improve the extraction of soybean oil is to conduct a
parametric study in a narrower pH, reaction temperature, enzyme concentration and reaction
time to predict the optimum values. Moreover, it is also necessary to study the use of a more
suitable process to minimize losses and to study the interaction of each parameter to attain
optimum condition.
2.4 Summary and Conclusions
Biodiesel as defined by the Biofuels Law (RA 9367) shall refer to fatty acid methyl
ester (FAME) or mono-alkyl esters derived from vegetable oils or animal fats and other
biomass-derived oils that shall be technically proven and approved by the Department of
Energy (DOE) for use in diesel engines, with quality specifications in accordance with the
Philippine National Standards (PNS).
The search and use of alternative fuels has been an issue since when the crude oil
reserves was realized to be diminishing and as a consequence, increasing crude oil price.
Early research on liquid fuels focused on vegetable oils but there are several problems on
engine performance with the use of the vegetable itself.
Until the research shifted on
removing the glycerol part of oil and esterifying the fatty acid with alcohol, then the product
was generally called fatty acid alkyl ester which is also now known as biodiesel. Methanol
23
was commonly used for the esterification process due to its advantages of being cheaper and
faster reaction rate compared with other alcohol.
In the Philippines, coconut oil is the pioneering and leading biodiesel produced
since coconut oil is the most abundant vegetable oil in the country. Several researches have
been conducted with the use of coconut oil for biodiesel production. And coconut biodiesel
or the coconut methyl ester (CME) was already an established industry. The two leading and
largest companies producing coco-biodiesel are Senbel, Inc. and Chemrez, Inc.
According to Diaz and Galindo of the Asian Institute of Petroleum Studies, Inc.
(AIPSI), the unique characteristics of coconut methyl ester and their implications to engine
performance are: coconut methyl ester has excellent solvency or solubility due to the medium
carbon fatty acids of coconut oil; high level of saturation compared to other biodiesel; and
high cetane number.
But the current price of coconut biodiesel is way above the conventional diesel. A
large variety of industries were also using coconut oil as a raw material and also very large
amount of coconut oil was used as cooking oil. Since coconut oil is the largest vegetable oil
commodity (for food and many other applications) in the Philippines, biodiesel research was
eyeing for another potential feedstock which is lower in cost and feasible for massive
biodiesel production.
Also, one of the policies of the Biofuel Law in mandating the use of alternative fuels
was to ensure the “availability of alternative and renewable clean energy without any
detrimental effect to the natural ecosystem, biodiversity and food reserves in the country”.
Jatropha is one of the plant oil that has potential feedstock for biodiesel production.
It was extensively studied at the UPLB.
24
Biodiesel is one of the emerging industries in the Philippines. The local government
also has mandated with the use of alternative fuels. And to further improve the biodiesel
research, a comprehensive literature review of the studies done in the Philippines was
conducted and possible research topic areas were identified.
After the biodiesel research literatures were collated and reviewed, it was
recognized that there are plenty of research areas that must be considered. These are gaps in
biofuels research. The prospects for biodiesel research and development are the following:
Firstly, massive amount of biodiesel must be produced to meet the demand
especially for the transportation sector. It should be noted that the biodiesel that must be
produced must not only comply with the standards but must be also affordable and
competitive with petroleum diesel prices. However, the research must not focus only or
concentrate to coconut and jatropha but must also explore on other potentially feasible
feedstock for biodiesel production.
A study also in increasing the productivity of the
feedstock (plant oil source) must be studied. Although there can be available land for
biodiesel raw material plantation, human population is increasing which implies an
incremental demand for energy and increase land use for shelter. At constant land area, future
biodiesel supply will become insufficient.
Next, having the oil, production of methanol must be considered. Methanol is
stoichiometrically supplied in excess to react with the oil to produce biodiesel. Hence, large
amount of methanol is also considered. But aside from methanol, ethanol can be used for the
transesterification process but the reaction kinetics of using ethanol must be investigated. An
advantage of using ethanol is that ethanol will be largely produced as part of the
government’s biofuel program and also it is less toxic compared to methanol.
25
In case of a success of using ethanol rather than methanol in biodiesel production,
comparative analysis between the properties of the biodiesel produced using different
alcohols must be studied.
Also, a comparative study between biodiesel from different
feedstock must be done. Different feedstock will result to different biodiesel characteristics
and properties. And the effect of blending different biodiesel at varying proportions must also
be investigated.
Having the oil and the alcohol for biodiesel production, the by-product glycerol, will
also be produced. A study in the purification or glycerol refining must be considered.
Moreover, conversion of glycerol into a more highly priced commodity must be studied.
And finally, process and operation integration/optimization involved in biodiesel
production are expected to be improved. Operations involved in oil extraction and the
transesterification process need research in improving its applications for biodiesel
production.
Therefore, there are a lot of areas of research in biodiesel and there are plenty of
areas that needed to be improved in the biodiesel research. Biodiesel industry is emerging
and still numerous aspects should be studied and investigated to further improve the research
and development in biodiesel.
Chapter 3
BIOETHANOL
Ethanol can be used as fuel substitute and its potential was known since World War
II when the Armed Forces of the Philippines were in search for a viable substitute. Later, in
the 1980s when there was oil crisis and oil price hike, ethanol as an alternative substitute for
conventional fuel was considered. Ethanol was also taken into consideration to replace
tetraethyl lead as an octane enhancer as a solution for high levels of lead in air pollution.
Nowadays, the use of ethanol-blended gasoline was mandated in the Biofuels Law. The
enacted Biofuels Act of 2006, RA 9367, mandates the use of Bioethanol as fuel to reduce the
country’s dependence on imported oil and to improve the environmental condition of the
country. The provisions include the mandatory blending of at least 5% by volume ethanol,
E5, two years from the implementation of this act and a minimum of 10% ethanol blend,
E10, within four years of its implementation. There are a lot of studies done in the
Philippines with the use of ethanol as fuel. In this chapter past studies on ethanol were
reviewed which covers the following topics: raw materials available for ethanol production;
pre-treatment process; fermentation processes, which includes the microorganism used, the
assessment of engine performance and air emissions, and the utilization of production byproducts.
3.1 Sources of Ethanol
Ethanol is a light alcohol that can be produced from the fermentation of
carbohydrates in plant. Ethanol derived from plants is regarded as Bioethanol. The three
26
27
main types of biomass raw materials for ethanol production: a) sugar bearing materials or
saccharine plants (such as sugarcane, molasses, sorghum, etc.) which contain carbohydrates
in sugar form; b) starches (such as cassava, corn, sweet potatoes, etc.); and c) cellulose (such
as wood, agricultural residues, etc.) for which the carbohydrates molecular form is more
complex (DENR, 1990-1993). In addition, Del Rosario (1982) also identified hemicellulosic
materials, which include pentosans and hexans, as potential source of ethanol. Hexans are
polymers of hexoses other than glucose and are major constituents of ‘sapal’, which is the
fibrous residue obtained after extracting ‘gata’ in coconut meat. Zayco and Rosario (1980),
has listed major potential biomass materials for ethanol production in the Philippines and
their expected yield. The list is presented in Table 3.1.
Table 3.1. Yields of Biomass and Ethanol for Some Agricultural Crops
YIELD OF FRESH CROPS ETHANOL YIELD
CROP
CROP
CYCLE
t/ha/season
t/ha/yr
li/t
li/ha/yr
(days)
Saccharine
Sources
Sugarcane
360
50-100
50-100
67
3350-6700
Nipa sap
252
83
21000
Coconut sap
60
83
5000
Sorghum
120
30
60
80
4800
Starchy Sources
Cassava
300
15-40
18-48
180
3240-8640
Sweet potato
100
15-40
54-144
125
6750-18000
Corn (maize)
110
1.0-5
3.3-16
400
1320-6400
Rice
120
1.8-6
5.4-18
420
2270-7560
Pineapple
104
11568
Studies conducted here in the Philippines are focused on producing alcohol from
sugar cane, corn, nipa sap, rice straw, cassava, sweet potato, sugarcane bagasse, molasses,
sapal, sweet sorghum, and even from banana peelings and guava, etc.
28
However, only sugarcane, cassava, and sweet potato were found to be attractive raw
materials for ethanol fuel production among all root crops (Villanueva, 1980). In there,
biological yields and their alcoholic yields based from the data of Menezes (1978) along with
Yang’s (1977) net energy ratios of cassava and sugarcane were analyzed. Whereas the yields
for sweet potato were determined on the assumption that 2.5 crops per year were used.
Villanueva concluded that cassava is technically feasible but economic analysis should be
clearly established. However, sugarcane’s alcohol is more efficient per unit area of land. As
recommended, cassava is likely to have an advantage on poor soils and under conditions not
suitable for sugarcane. On the other hand, sweet potato for alcohol production was found to
surpass cassava in economic yield per hectare per year.
The use of nipa sap as feedstock for ethanol production was also studied. It was
determined that molasses is still more advantageous as raw material in ethanol production
than nipa sap. The advantage of using molasses over nipa sap as raw material is that for the
same amount of alcohol produced, a smaller quantity of molasses is required (Lirag Jr. et al.,
1980).
Sugarcane juice can be directly fermented and produced into ethanol that could give
a typical theoretical yield of 70 liters of ethanol per ton of sugar. However, ethanol
production directly from sugarcane juice will result in the loss of sugar production capacity.
An alternative is to make use of molasses, a by-product of normal sugar production, as
feedstock. Ethanol yield for molasses are in the order of 0.28 liters of ethanol per kg of
molasses (Tan et al., 2005). The fibrous residue, bagasse, incurred in sugar and ethanol
production then can be utilized as fuel for steam processing that can reduced production cost
by minimizing energy input.
29
Tan et al. (2005) also reported that corn is another viable feedstock for ethanol
production. Production of ethanol from corn involves milling of the grain using either wet or
dry process, mashing, saccharifying, fermenting, and distilling that could give an ethanol
yield of about 0.37 liters/kg of grain. Corn residues (corn stover) can also be used as fuel to
supplement the heat needed for the production.
Del Rosario (1982) also identified sweet sorghum and pineapple to be attractive
sources of ethanol. Sweet sorghum is a saccharine crop with nearly 90% of the soluble
carbohydrates in the form of stalk juice sugar and the remaining 10% as grain starch. The
processing of sweet sorghum, just like sugar cane, produces stalk bagasse which can be used
as fuel for the production of the process steam. It is also an attractive crop for farmers
because of its resistance to drought. Grain sorghum could be grown in uplands as well as in
the lowland after the rice crop. A pilot study conducted by the International Crop Research
Institute for the Semi-arid Tropics (ICRISAT) scientists revealed that sweet sorghum is the
best alternative raw material to supplement sugarcane in ethanol production. The estimates
made by the researches of ICRISAT also reported that the per liter cost of production of
ethanol from sweet sorghum is 4.28% higher than from sugarcane molasses. On the contrary,
the higher production cost is compensated by the grain yield of 1 ton per hectare, which can
be used as human food or animal feed, and the superior quality of ethanol (Dela Cruz, 2004).
The potential of sweet sorghum as ethanol source is currently being studied by the Research
and Development team of the University of the Philippines-Los Baños. The study is a joint
project with the Department of Agriculture-Bureau of Agricultural Research (DA-BAR) and
ICRISAT. The project focuses on conducting strategic research on hybrid development of
sweet sorghum (Hernandez, 2007).
30
Pineapple, on the other hand, is also an attractive source of ethanol. Del Rosario
(1982) stated that the alcohol productivity for pineapple was 11,568 liter per hectare per year
which was slightly greater than that of sugarcane and is 1.5 times that of cassava (see Table
4). Moreover, the water requirement for pineapple is only one-half that of sugarcane and twothirds that of cassava. Thus, pineapple is a suitable crop for alcohol where water supply is
minimal.
Another promising energy source is cellulose contained in agricultural wastes and
by-products. Cellulose is the most abundant organic substance in the world. It makes up
approximately 50% of the cell wall material of wood and plants and between 25 to 50% (dry
basis) of sugarcane bagasse, rice straw, rice hulls, wood and other lignocellulosic materials
(Del Rosario, 1982). Cellulosic wastes from agriculture and forestry activity offer some
potential as sources ethanol fuel. Some agro-forestry wastes were estimated by the DENR
(1990-1993) and are shown in Table 3.2.
Higher alcohol yields occur when starchy or cellulosic materials are utilized as
feedstock. However, saccharine materials like sugarcane molasses are favored because of
their reduced production costs (Del Rosario). The cost is due to the reason that production of
ethanol from saccharine materials is relatively simpler and more straightforward compared to
the other raw materials for ethanol production. Usually it requires little or no preliminary
treatment other than dilution and clarification (Joson, 1978).
Promising raw materials for the production of fermentable sugars are coconut meat
residue and sugarcane bagasse (del Rosario, 1977). Del Rosario (1978) cited the studies
which showed that almost one-half of the dry weight fat-free coconut residue can be
converted into reducing sugars by treatment with 5% (w/v) sulfuric acid at 126oC.
31
Table 3.2. Production and Oil Equivalent of Agro-Forestry Wastes
Annual Production
Oil Equivalent
Agro-Forestry Waste
(million MT)
(millions of barrel)
Rice Hull
1.5
1.39
Rice Straw
9.7
14.54
Corn Cob
0.6
0.87
Corn Stalks
2.7
4.05
Bagasse
7.5
12.10
Wood Wastes
1.3
2.00
Logging Wastes
2.0
4.00
Coconut shell
1.9
8.72
Coconut Petiole
4.6
7.10
Peanut Shell and Coffee Hull
0.0
0.40
Grass, reeds, leaves
0.0
0.50
The resulting hydrolyzate contains 60% mannose, 18% glucose and 18%
disaccharide. However, only 35% of the dry material of sugarcane bagasse can be converted
into reducing sugars. Conversion of 1/5 of dry bagasse into sugar consisting of 69% pentoses
and 25% glucose resulted by pretreatment with 2% sulfuric acid at 126oC for half an hour.
Saccharification with 20% H2SO4 at 130oC for one hour converted 15% of the prehydrolyzed
bagasse into sugar which consisted about 95% of glucose.
A useful comparison of some of the raw materials for alcohol production can be
made using the present cost of the fermentable material contained in these raw materials.
There are abundant source of materials that can be used for ethanol production. Researches
focus on how to improve ethanol production using these raw materials to be more
competitive with the conventional fuel. It has been noted that the use of food crops for
ethanol production may have some effect on sugar and grain prices, although the short fall
can easily be compensated for by increase in cultivated land area or crop productivity
32
Alternatively, crop yields can be increased through the use of hybrid cane or high-yielding
corn varieties without requiring additional cultivated land (Tan et al., 2005).
Tan et al. (2005) evaluated the energy ratios of feedstocks to guide for the potential
of raw materials into ethanol production. Energy ratios, the ratio of total useful energy
produced in a system to the energy demands of the system, were used to evaluate for the
feasibility of raw materials. The values of this parameter must be greater than 1 in order for
the fuel to be an effective alternative source. In this study, favorable results were calculated
for sugarcane and corn based ethanol. The petroleum energy ratio for sugarcane and corn
were estimated to be 3.1-4.2 and 1.79, respectively. While the fossil energy ratio values for
sugarcane and corn were determined to be 3.0-4.2 and 1.43-1.52, respectively. The study
revealed that cassava-derived ethanol is not favorable at the petroleum energy ratio of 0.50.6.
3.2 Microorganisms Involved in Ethanol Production
The production of ethanol from carbohydrates involves microorganism such as
yeasts and fungi. Some microorganisms are involved in the pre-treatment processes of raw
materials for ethanol production like those involved in the enzymatic hydrolysis of starch.
And more importantly, microorganisms are used to ferment the glucose into the desired
ethanol.
33
3.2.1 Amylase-Producing Bacteria
In alcohol production, starch has to be converted first into simple sugars before it is
fermented to ethanol. Enzymes are favored over acid in starch hydrolyzing since they are
more selective and the product yields are higher. Improvement in the conversion of starch
into ethanol will result from the production of highly active amylases (Del Rosario, 1982).
Amylase producing-bacteria are utilized in this process.
Many species from the genus Bacillus produce amylase. Bacillus subtilis is used in
the industry but it does not imply that it is the most efficient bacterial amylase producer. No
study has been conducted yet to compare the amylase producing-ability of all the amylase
producing Bacillus species (Raymundo, 1982). However, based on iodometry method, a
comparison of amylase activity of four species, Bacillus subtilis, B. cereus, B. megaterium
and B. lichenformis was done and it showed that the latter has the highest activity. It shows
that amylase producing ability is strain specific.
Rumen bacteria like Bacteroides and Streptococcus bovis have long been known to
produce amylase. According to Raymundo (1982), it was shown that the amylase produced
by S. bovis had a higher hydrolytic activity on raw starch compared with other bacterial
amylases.
3.2.2 Enzymes for Cellulose
The enzymatic saccharification of cellulose is a worldwide research interest. But
enzymatic process is not cost effective compared to acid saccharification process.
An
improved strain of Trichoderma viride, a cellulose-producing mold, offers potential in
34
enzymatic process (Del Rosario, 1982). Further genetic improvement of existing cellulase
producers, or the discovery of highly cellulytic microorganisms, could make the enzymatic
saccharification of cellulose competitive.
3.2.3 Alcohol Producing Microorganisms
There are several species of microorganisms that can be utilized for ethanol
production. Commonly used among these are fungi and yeasts. Saccharomyces cerevisiae is
one of the commercially used ethanol producing yeast species.
Halos (1982) discussed the microbial aspects of alcohol production by yeasts and
fungi. She enumerated several factors affecting ethanol production by yeast species that
must be considered in conducting researches. These are: a) the types of sugar, the ability of
the yeast to utilize these sugars depends upon its ability to allow the sugar to pass intact
across the cell membrane and/or its property of initially hydrolyzing the sugar outside the
membrane followed by entry into the cell by some or all of the hydrolytic products; b) the
presence of oxygen, yeast strains vary in their requirement for oxygen; c) temperature,
different yeast strains perform well at different temperatures; d) pH, there is usually a
preference for strain that perform well at desired pH; e) tolerance to ethanol, yeast cells could
not continuously produce ethanol. Cell lysis occurs when a particular concentration of
internal ethanol is reached. Physiological conditions can be modified to increase the level of
alcohol tolerance of the strain used. The ability of yeast to tolerate ethanol can also be
increased by increasing its ability to get ethanol out of the cell into the medium; and f)
presence of other microorganisms, some yeast strains perform better if no other
35
microorganism is present. Though, it would be better if strains perform efficiently whether
the medium is sterile or not.
Genetic engineering techniques have been found successful in laboratory strains of
S. cerevisiae. There are attempts in private industrial laboratory to study on its use as a
method of improving alcohol producing-yeast (Halos, 1982).
Cells of Saccharomyces cerevisiae TJ-1 isolated in Thailand are highly cohesive and
form flocs quickly resulting to sedimentation in the fermentation medium (Taguchi, 1982).
The sedimentation rate of S. cerevisiae TJ-1 was a function cell concentration and studies
show there is a linear relationship between sedimentation velocity and cell concentration. An
increase in sedimentation velocity corresponds in a decrease in cell concentration.
The strain TJ-1 was hybridized with other high-alcohol producing strains by the
protoplast fusion technique to improve the yield of ethanol. The experimental results on
alcohol production of TJ-1 strain is presented in Table 3.3. The bacterium Zymomonas
mobilis was found to produce alcohol at a rate comparable or even higher than yeast under
certain conditions (Raymundo, 1982). Among some of the advantages with the use of Z.
mobilis over yeast for alcohol production are: possible higher alcohol yields, shorter
fermentation time, and capability of growth on higher sugar and ethanol concentration
(Rogers et al., 1979, 1982).
Rogers et al. (1982), presented the Zymomonas process for ethanol production.
They focused on Zymomonas bacterium due to the reported studies of the advantages
compared yeast. One of the studies initiated on strain selection and genetic manipulation. A
strain improvement program was initiated from strain ZM1, a strain ZM4 was isolated which
36
had a number of advantages including higher specific rates and an enhanced ethanol
resistance. The objectives of the genetic manipulation for ethanol production have been to
Table 3.3. Alcohol Production by S. cerevisiae TJ-1 and Its Derivatives
Temperature
Alcohol
Flocculating
Cross
Strain
Medium
o
( C)
Production
Character
TJ-1
YPD
30
10.5% (w/v)
++
YPD
35
8.4
++
K7-64C
YPD
30
14.2
K11
YPD
30
14.6
Strain 13
YPD
30
11.8
N1
YPD
30
13.6
TJ1xK7-64C
MS17
YPD
30
13.4
++
YPD
35
10.5
++
Molasses
30
13.6
++
Cassava
30
13.6
++
MS15
YPD
30
14.7
+
YPD
30
14.9
+
MS15-5A
MS15-3B
YPD
30
14.2
++
TJ1xK11
KL411
YPD
30
12.7
+/KL501
YPD
30
14.4
+/TJ1xstrain 13
TS113
YPD
30
11.8
TJ1xN1
AM12
YPD
30
16.3
++
YPD
40
12.3
++
develop strains with enhanced ethanol tolerance, to isolate stable flocculent strains and to
broaden the range of fermentable substrates aside from glucose, fructose and sucrose. The
results of the genetic program of Rogers and his colleagues presented at UPLB in 1982 were:
strains of Z. mobilis have the potential of genetic manipulation; a range of natural plasmids
have been isolated and a bank of auxotrophic mutants of Z. mobilis has been developed; an
ethanol tolerant strain has been isolated; a highly flocculent strain has been isolated; and a
salt tolerant strain has also been isolated which has enhanced ability to ferment molasses.
37
The kinetic evaluation of Zymomonas mobilis in continuous culture was investigated
by Rogers (1982). He was able to produce the kinetic data of fermentation using Z. mobilis
on 10% glucose medium. Clostridium thermocellum is another bacterium that has a potential
in ethanol production.
As cited by Raymundo (1982), it is anaerobic, thermophilic,
cellulolytic bacterium which can ferment cellulose and cellodextrin but not glucose to
produce primarily H2, CO2, ethanol and acetic acid. Cellulose can be converted to ethanol
even without pretreatment of biomass but its utilization in large-scale is impractical due to
inhibition by low concentration of ethanol. Improvement of this strain (high yield ethanol,
ethanol tolerance, etc.) and further research has still to be done using more modern
techniques like genetic engineering so it can be utilized in large-scale.
Escarilla et al. (1993) evaluated the biomass yield and ethanol production of
Lambanog yeast, Saccharomyces cerevisiae, Candida tropicales, Candida lipolytica, and
Rhodotorula rubra. The ethanol fermentation performance of the yeasts used is summarized
in Table 3.4. The results showed that higher ethanol production can be achieved at high sugar
medium than in low at 30oC. Lambanog yeast, S. cerevisiae, and C. lipolytica produced more
ethanol at 38oC from the low sugar medium. All yeast strains except Rhodotorula rubra were
observed to be thermotolerant strains. Lambanog strain was exceptionally thermotolerant as
yielded 3.18% (w/v) ethanol at 42oC.
38
Table 3.4. Alcohol Production Yeast Strains in Shake-flask Culture at Different
Temperatures
Ethanol Concentration, a Ethanol Concentration, b
Yeast
% (w/v)
% (w/v)
o
o
30 C
30 C
38oC
42oC
Lambanog
7.26
0.83
7.16
3.18
S. cerevisiae
5.89
1.70
7.56
1.68
C. tropicales
6.96
3.87
2.80
0.70
C. lipolytica
11.01
4.42
6.58
1.46
Rhodotorula rubra
6.96
2.20
a- Molasses medium with 20% initial sugar content
b- Molasses medium with 5% initial total sugar content
Source: Escarilla et al. (1993)
3.3 Studies in Ethanol Fermentation
The most direct pathway of ethanol production is the fermentation of sugar into
ethanol (Tan, 2006). Ethanol can also be produced from starchy and cellulosic materials with
the addition of preliminary steps that will further convert these materials into sugar or
saccharine compounds. Ethanol production from starchy materials requires additional and
prior step of hydrolyzing starch into glucose. The conversion of starch into glucose consists
of three steps: gelatinization-dissolution of starch into a mash by steam cooking; liquefaction
(dextrinization) – breakdown of the gelatinized starch into short fragments or dextrins by
means of enzymes or dilute acid; and saccharification or complete conversion of the dextrins
into glucose (Del Rosario, 1982).
Utilization of starch for ethanol production requires
additional energy input so as an additional cost.
In Figure 3.1, the production of ethanol from carbohydrate polymers of hexoses is
illustrated in terms of their mass. The saccharification step in Figure 2 wherein there is either
an addition of acid catalyst or enzyme catalyst explains the increased production costs of
39
starch and cellulose as raw materials. Use of acids, however, are economical yet enzymes are
favored over the former catalyst since they are more selective and the product yields are
higher (Del Rosario, undated).
yeast
(C6 H10O5 ) n + nH2O enzymes
oracid
→nC6 H12O6 
→ 2nC2 H5OH + 2nCO2
starch/
cellulose/
hexane,
162 grams
hexose,
ethanol,
180 grams
92 grams
Figure 3.1. Ethanol Synthesis
3.3.1 Ethanol Production Using Different Substrates and Microorganisms
Current biomass production technology in the Philippines involves three main
processes: (a) extraction of the carbohydrates and conversion into the water soluble (6 to 12
carbons) sugars; (b) fermentation of these sugars into ethanol; and (c) stripping and
separation of ethanol from water and other products by distillation. A simplified process flow
diagram by (Armas and Cryde, 1984) for sugarcane and starch based alcohol production is
presented in Appendix D. A batch culture of the combined Aspergillus awamori bacteria and
Saccharomyces cerevisiae yeast produced 4.3% alcohol by weight from 15% cassava flour
slurry in 39 hour (Del Rosario et. al, 1984). Plot of log yeast cell concentration versus
fermentation time of α-amylase thinned cassava root flour using the combined
microorganisms after 72 hours was reported to obtain the highest ethanol concentration and
starch-into-ethanol conversion.
Two-stage continuous fermentation using A. awamori in airlift fermenter and localRed Star Brand yeast in a tower fermenter for a total residence time of 18 hr was studied by
Del Rosario and Wong in 1984. A residence time of 12.5 hour for the first stage resulted in
40
12.5% sugar concentration and a saccharification efficiency of 88% while a residence time of
5.6 hour for the second stage gave an alcohol concentration of 5.3% alcohol and a starchinto-ethanol conversion efficiency of 72.5%. Failure to attain the steady-state value in the
second stage was due to washout of the yeast cells. The effect of this washout problem is also
reflected in the low starch-into-ethanol fermentation efficiencies obtained due to the low
yeast concentration in the fermenter. Hence, it is recommended that the use of either a
flocculent yeast strain or yeast immobilized on solid supports must be investigated.
Del Rosario (1983) described comprehensibly the production of sugar and alcohol
from rice straw. Saccharification process was done after delignification, process termed for
separating lignin from cellulose and hemicellulose. Delignification was found to be effective
in either of the following treatments: ball milling, rapid decompression, and alkali treatment.
Next, under a maximized saccharification value of 23.6% and a reducing sugar concentration
of 3.8% H2SO4 at 1:3 substrate-to-acid ratio (w/v), 1 hour autoclaving at 20 psig, 1 kg of rice
straw yields 236 g of reducing sugars whose concentration is 3.8% (or 38 grams per liter).
This can produce ethanol using yeast and a xylose-fermenting microorganisms, such as
Pachysolen tannophilus as recommended. However, the two-stage production of ethanol was
not as good in the research done by Kim et al. (1981) as cited by Del Rosario known as the
one-stage process. The process is done by simultaneous saccharification and fermentation
which is being performed by Trichoderma species and thermophilic yeast. It resulted to a
higher ethanol yield at 45°C after 48 hours compared to the two-stage (enzymatic) process.
In conclusion, the technology of producing ethanol from rice straw has been developed as a
result of the efforts of researchers in several countries. The author added that large-scale
utilization of lignocellulose in rice straw for sugar and ethanol production will depend on the
41
development of a cost-effective pretreatment procedure combined with locally available
enzymes or a vastly improve acid saccharification process. However, it would be better if the
continuing studies would focus on the cheaper production of the Trichoderma species and
thermophilic yeast as well as to develop a technology using local resources that would
optimize fermentation of rice straws since both acid or enzyme method was concluded to
have high processing costs.
The design flowchart on alcohol production (see Figure 3.2) from Nipa as
investigated by Gibbs did not use the typical Baker’s yeast for fermentation as studied by
Lirag. On average, fermentation would take long for about 36-48 hours upon adding pure
strain of Magne yeast. Preparation of the mash is done by sterilization of the sap and control
of the pH of the mash adjusted in the range of 4 to 5. Furthermore, sugar concentration
should have a concentration of 10%-18%. Subsequently, the distillation step is carried out 24
hours a day. It is a batch process with constant reflux. In effect, there are 10 batches per day
with a one (1) hour distillation time and forty five (45) minutes per batch. Reflux ratio is two
(2) at a temperature of 84°C which yields to 70% alcohol in the condensate. Boiler provides
steam which uses firewood as fuel. (Lirag et al., 1980).
Lorica et al. (1982) made a preliminary investigation on the fermentation of nipa sap
by means of seed cultured Zymomonas congolensis instead of yeast. It was observed that an
increase in the number of days it was allowed to ferment tends to increase the alcohol yield
yet no data was reported that describes its optimum condition. Dehydration followed after
fermentation as an alternative to distillation in order to bring down cost. From there, it was
found that cornstarch and Avicel gave an appreciable alcohol concentration as well as the
highest recovery than the cornstalk when used as dehydrating agent. However, alcohol
42
95% ETHANOL
Figure 3.2. Alcohol Production from Nipa Sap
content is very low and it was suggested to conduct a study on the isolation process of the
Zymomonas strains hoping to improve the succeeding fermentation runs. Further, extended
43
research on dehydrating agents aside from the later agents experimented was recommended.
In line with these, focus on CaO should be given priority because its dehydrating efficiency
would determine if alternative dehydrating agents is necessary. Otherwise, modification of
the dehydration set-up must solve the problem on dehydration.
Large waste amounts are generated in the cultivation of corn. A plant can produce a
single corn cob after which it will not be generative. Increase in utilization and demand of
corn will correspond to larger corn waste. To make ethanol production environmentally
acceptable waste must be minimize by utilizing into other viable products or into another
process for ethanol production.
Tongson (2006) studied the saccharification and
fermentation of corn waste mixtures to produce ethanol. The study focus on the effects of
pretreatment using hot water and dilute acid and enzyme concentration, determination of the
fermentation profile for ethanol, reducing sugar, and biomass concentration. In using the
combination of dilute acid pretreatment and cellulose at 10% (w/w), the highest percentage
of saccharine and ethanol concentration of 26.27% and 4.897% (v/v) can be achieved that
will result in an 86.61% efficiency. For pretreatment using hot water and cellulase level of
10% (w/w) the percentage of saccharine, ethanol concentration, and fermentation efficiency
obtained were 24.26%, 4.39% (v/v) and 77.02%, respectively. These values showed that the
pretreatment using dilute acid (0.5% (v/v) H2SO4) and hot water pretreatment prior to main
saccharification using 10% and 20% (w/w) cellulase were not significant. Tongson (2006)
recommend to study further the optimized conditions (pH, temperature, substrate
concentration) for the saccharification and fermentation process.
44
3.3.2 Non-Cooking Ethanol Fermentation
Non-cooking ethanol fermentation uses microorganisms that can utilize raw starch
in ethanol fermentation thus, avoiding energy consuming gelatinization (cooking) process.
These alternative scheme, referred as the ‘Amylo process’, uses two microorganisms in order
to convert starch into ethanol without the external addition of amylase enzymes (Wong,
1982). There are researches that had been conducted on the production of ethanol from raw
starch from the point of view of energy and resource savings.
Hayashida (1982) discussed on the digestability of raw starch by fungal amylases
for fuel alcohol production. It was based on a single strain of Aspergillus awamori var.
kawachi which produce raw starch-digestive glucoamylases. As cited by Taguchi (1982),
Ueda and Hayashida of Kyushu University had done a study on alcoholic fermentation of
starch without cooking by using black koji amylase. He also cited the study of Yamamoto of
the Osaka Municipal University using potato.
Hayashida and Flor (1982) presented the enzymatic saccharification of raw starches
and its application to the production of ethanol. They demonstrated the saccharification of
raw starches by the use of raw starch digestive amylase produced by protease-glycosidaseless mutant HF-15 of Aspergillus awamori var. kawachi by the coordinated saccharificationfermentation process, and the use of fungal mycelia as high concentration ethanol-producing
factor. The effects of pectin depolymerase and glucoamylase on the saccharification of noncooked sweet potato was demonstrated by Taguchi (1982).
Possible savings in energy in ethanol production was investigated by Elegado et
al.(1990) by simultaneous saccharification and fermentation (SSF) of raw cassava starch
powder by a mixed culture of Rhizopus sp. and S. cerevisiae in a gas-circulating bioreactor.
45
This modified process using raw-starch digestive microorganism eliminates the cooking step
and in combination with yeast, simultaneously saccharifies and ferments the raw starch into
ethanol.
As cited by Del Rosario (1982), there were also researches with the yeast
Schwanniomyces alluvius which ferment soluble starch into ethanol directly at conversion
efficiency of greater than 95%.
3.4 Ethanol Fermentation Systems
The promising innovations in alcohol fermentation technology as identified in the
study of Del Rosario (undated) include: (a) continuous-flow process with or without cell
recycle, (b) rapid fermentation using high yeast levels, (c) more efficient and less energy
requiring fermenter designs, (d) use of rapidly fermenting microbial types such as
Zymomonas
mobilis
and
pentose-metabolizing
bacteria,
e.g.
Clostridium
thermohydrosulfuricum and Bacillus macerans, and (e) vacuum fermentation process. In all
of the cases, the study found the continuous-flow fermentation using a tubular fermenter
when adapted to the country’s condition is expected to gain savings in the total investment
costs based from the analysis that the size of the optimized continuous fermenter is less than
1/17 that of the batch fermenter for the same ethanol productivity. However, encountered
problems such as contamination, cell mutation, and the addition of pumps, and control
devices would hinder its success unless modified. As for the others, it is encouraged by the
author to continue on investigating their applicability in the overall status of the Philippines.
Continuous-flow conversion of molasses sugar into ethanol was studied using
tubular type of reactor (Del Rosario et.al, 1981). Furthermore, comparative analysis of tower
46
versus airlift fermenter was done in continuous fermentation. It was found that both exhibited
similar values under the same conditions. Results showed that fermentation efficiency was
only 76% for both fermenter wherein the volumetric productivities was approximately at
19.6 g/l-hr at a dilution rate of 0.27 hr-1. It was proposed that addition of fresh yeast higher
than 33 g/L would give better alcohol concentrations.
Rogers et al. (1982) presented a summary of the productivities and final ethanol
concentrations for various fermentation systems with Z. mobililis given in Table 3.5.
Table 3.5. Comparison of Various Fermentation Systems with Z. mobilis (pH=5.0, T=3035oC)
Input
Ethanol
Maximum
System
Glucose (g/L)
(g/L)
Productivity (g/L/h)
Batch culture
250
117
5
Continuous culture
150
65
12
Semi-batch culture
150
73
50
Imobilized cell
150
63
50
Reactor
Simultaneous
Saccharification and
130
60
60
Fermentation (SSF)
Vacuum Fermentation
185
200
85
(Cell Recycle)
(condensate)
55
(fermentor)
Continuous culture with
140
65
120-200
Cell recycle
A summary of the fermentation systems and processes done by BIOTECH and DOST
(DENR, 1989) was presented in Appendix B and Appendix C.
47
3.5 Separation and Purification Processes
Ethanol being produced from fermentation must be purified to eliminate purities and
achieved higher ethanol concentration. Distillation is usually performed to separate ethanol
but this could give only a maximum of 95% ethanol with water as the residual. This is
attributed to the azeotrope formed at 95% ethanol which inhibits any separation. The residual
water will make this product unsuitable for blending with gasoline, so an additional
processing step is required to yield anhydrous ethanol. The dehydration of ethanol can be
done in many ways. There are many patented technologies that have been established for the
purification of ethanol.
3.6 Waste and Wastewater Management
Large amount of wastewater are being produced in the production ethanol from
sugarcane. Secreto (2005) conducted an alternative way to utilize distillery slops to minimize
the wastewater generated as well as the amount of water used during the production. The
study performed assessed the feasibility of using distillery slops as a medium component and
alternative diluents to fresh water in molasses medium for alcohol fermentation. Two yeast
strains, Saccharomyces cerevisiae 2008 and Saccharomyces coreanus 2025, were chosen for
the screening experiment based on ethanol production in sterile and unsterile molasses-based
fermentation media. Different proportions of distillery slops in the molasses medium at 0%,
20%, 30%, 40% and 50% (v/v) were tested in a standing flask culture on two different
species, S. Cerevisiae 2008 and S. Coreanus 2025. The experiment results for the best
medium formulation for slops supplementation and the better performing microorganisms
48
were evaluated based on the ethanol concentration after 48 hours and the specific ethanol
productivity. The combination of slops medium and microorganism was cultivated in a 30-L
batch fermentor to evaluate its performance in an industrial bioreactor, and evaluate the
kinetic parameters related to growth and production of ethanol. In the standing culture
experiment, it was determined that the best combination of slops medium and yeast strain
was 40% slop supplementation and with ethanol concentration of 10.9% and ethanol
productivity of 4.7 x 10-8 mg ethanol/ cfu-h. Whereas, ethanol concentration after 48 hours as
performed in the 30-L fermentor, 12%(v/v), is higher than the reaction in the standing flask
culture. This advantage of a higher ethanol yield in the fermentor can be attributed to better
reaction conditions inside the bioreactor as compared to the standing flask culture. The
conditions particularly pertain to agitation and oxygen supply for the cell growth phase. The
fermentation in his conditions delivered 92.59% efficiency and 3.7x10-8 mg ethanol/cfu-h
specific ethanol productivity. Secreto (2005) also found out that S. cerevisiae 2008 is a better
performing strain than that of S. cerevisiae HBY3, an industrial strain, which was also
cultivated in the same manner as S. cerevisiae 2008. S. cerevisiae HBY3 fermentation
yielded only 8.2% ethanol, fermentation efficiency of 85.19% and ethanol productivity of
2.2x10-8 mg ethanol/cfu-h. The results indicate that the strain S. cerevisiae 2008 is a more
tolerant than S. cerevisiae HBY3 strain. Thus, the S. cerevisiae 2008 grown in the 40% slop
substitute gave the best results in terms of ethanol production. In this study, supplementation
of molasses medium for ethanol fermentation distillery slops was proven to be feasible and
that could contribute savings in water use. Further, the UP Biotech yeast isolate S. cerevisiae
2008 was assessed as a high ethanol producing strain for slop supplement medium. A similar
study conducted using unsterile media must be performed as recommended by Secreto
49
(2005) to confirm the result of their study. This is also because industries used unsterile
media. After the evaluation of results in unsterile media, study must proceed to the evaluation
of optimum fermentation conditions like agitation speed and aeration rate. It was also
recommended that high-performance liquid chromatography (HPLC) be used in the analysis
of sugar concentration to obtain results that are more reliable. The author also added that
phenol-sulfuric acid method is reliable but is prone to errors when higher dilutions are
employed.
Efficient waste recycling of distillery effluent offers potential in utilizing it as
fertilizer that will benefit the sugar industry. The studies on the use of distillery slops as
fertilizer in the Philippines are discussed as follows:
Tetangco and del Rosario (1980) reported that when slops were applied at planting
time, the plant height, tiller count and number of functional leaves of sugarcane were higher.
As shown by experiences in Brazil and Taiwan, Madrid et al. (1982) noted that there would
be no attendant crop-environment hazards with distillery slops application to cane. This
study showed that the time of application significantly influenced plant height and number of
functional leaves while the effect of different rates of slop application was reflected only in
plant height. Gonzalez and Tiangco showed that there was improvement in the soil reaction
(pH), soil available potassium oxide, calcium and magnesium by distillery slops application.
Magbanua, et al. (2000), studied the utilization of distillery effluent as fertilizer for
sugarcane plantation. They conducted field experiments to evaluate the efficacy of distillery
effluent on sugarcane. Three application rates (200, 300 and 400 m3/ha) were tested on plant
and ratoon cane. Results showed that application of 400 m3/ha distillery effluent significantly
50
increased plant height but not tiller number of ratoon cane at 3 months after planting.
Tonnage and sugar yield increased by 9-25% and 7-24%, respectively due to treatment.
Bugante et al. (1986), on the other hand, focused on utilizing the distillery slops in
producing methane. They studied the performances of single and two-phased fermentations
of slop waste under mesophilic and thermophilic conditions and were tested for the
efficiencies of these processes in terms of biogas produced, reduction in COD value, and
utilization of volatile fatty acids forms at different COD loadings. The results showed that
the two-phase thermophilic fermentation was the most efficient process with 60% methane
produced, 27% COD removed, and 50% volatile fatty acid at a loading rate of 0.015 kg/L.
As recommended in the study, further improvement in the reduction in COD may with the
proper manipulation of parameters, development of new fermentor designs, and selection of
high methane-yielding methanogens.
3.7 Ethanol Used as Fuel
Most of the properties of ethanol resembles to those of gasoline thus, making it
suitable for use as fuel substitute or additive. Table 3.6 summarizes the properties of ethanol
and gasoline.
Tan et al. (2005) stressed the safety measures are necessary on handling ethanol
because ethanol flames are non-luminous. Therefore, it would be difficult to detect and
control ignition during daytime. These can be developed by incorporating additives to
increase flame luminosity.
51
3.7.1 Ethanol as Gasoline Substitute and Additive
The cut-off of the Philippine supply of oil from exporting countries during the
World War II forced the Armed Forces of the Philippines (AFP) to search for a viable
substitute from indigenous materials. The AFP found out that ethanol was the best substitute.
Table 3.6. Properties of Bioethanol and Unleaded Gasoline
Property
Ethanol
Unleaded Gasoline
Chemical Formula
C2H5OH
C4 to C12 chains
Oxygen Content (wt%)
35
0
Octane Rating ([RON+MON]/2)
98-100
87.5% (minimum)
Net Heating Value (MJ/kg)
26.5
41.8-44.1
Net Heating Value (MJ/l)
21.2
31.8-32.6
Density (g/ml)
0.79
0.72-0.78
Reid Vapor Pressure (atm)
0.16
0.61 (maximum)
Stoichiometric Fuel-Air Ratio
9
14.7
Flammability Limits (vol. %)
3-19
1-8
Source: Tan et al.(2005)
Camina (1978) mentioned in his study the earliest work in the use of ethanol as
motor fuel which was conducted by the U.S.A. in 1915 while Teodoro (1931) were the first
to undertake researches in this matter. In these researches, they found out that using straight
ethanol as fuel causes difficulty in starting the engine caused by the lower vapor pressure of
alcohol as fuel. It was also determined that using ethanol as fuel kept the cylinder cool
resulting in more power output and efficiency. As Camina mentioned Teodoro et. al. (1931)
found that greater amount of ethanol is required to cover the same mileage with gasoline. In
his experiment, he found out that 1.33 gallons of ethanol covered the same mileage as 1.00
gallon of gasoline. Teodoro et. al. (1931) also determined that ethanol gave less carbon
deposit than gasoline due to the fact that it is complexly oxidized with its initial composition
52
containing oxygen. Camina (1978) conducted a stationary and road test as well as a field test
of using straight denatured ethanol. In the stationary test, an 18hp, 4 cylinder gas engine was
used while two army jeeps, where one the carburetor of the jeep was modified and adjusted,
was used for the road test. Several AFP jeeps used in the field test were converted to alcoholfed engines to give a closer average data. Camina (1978) found out in his experiment that it
is possible to replace gasoline with straight denatured alcohol of 189 proof (94.5%) but with
an increase consumption of about 75% to 70% over the required consumption of gasoline
with the same mileage. He also reported that starting the engine with straight alcohol of 189
proof is not a problem at a temperature beyond 60˚F. Thus, it is unsuitable for high altitude
application. He also concluded from the actual field results that the used of denatured ethyl
alcohol ( 189 proof) gives smooth engine operation, greater acceleration after warming, clean
engine cylinders, absence of vapor lock and oil dilution, cooler engine, greater power output
of the engine under when carburetor
is adjusted and more fuel consumption which
corroborate the findings of the previous researches. During this period, alcohol as motor fuel
cost more than gasoline. Camina (1978) indicated the increase of production of ethanol as
well as exemption of fuel alcohol from Internal Revenue Taxes can reduce the cost of
alcohol. He also added that expansion of sugar plantation acreage to increase alcohol
distilleries capacities is also necessary to achieve lower cost of ethanol.
During President Marcos’s regime, he addressed a directive in the partial
displacement of the country’s total gasoline consumption, and to promote indigenous energy
source as well as to create a new market for surplus sugar production. In line with this
directive, Bernardo (1978) conducted a study on the engine assessment and performance
using “hydrous” alcohol as applied in a wide variety of vehicles representing a good cross-
53
section of the country’s total car population. Acceptability of using this alcohol in sparkignited internal combustion engines was determined on the basis of reliability and
performance. Hydrous alcohol was employed in his study because during this period, local
distilleries involved in ethanol production using molasses are not yet suitably equipped in
producing high grade purity (99.5 %) ethanol. Ethyl alcohol of 190 proof (95%) was blended
with premium gasoline for a 15 % by volume ethanol to 85% gasoline blending composition
which is the Alcogas composition employed in his study. This blending distribution was
based from the miscibility studies using rectified 190 proof ethanol and Petron’s premium
gasoline. It was noted in this experiment that an immiscibility region existed up to 14.5% by
volume alcohol while at 15% and beyond all blends were clear and homogenous. In regular
gasoline complete miscibility was only attainable at 20% volume and higher which indicates
that hydrocarbon composition is a limiting factor in obtaining a homogenous mixture with
190 proof alcohol. He also confirmed the miscibility of anhydrous alcohol in all proportions
in both fuel types. Bernardo (1978) also observed that at 60˚F and lower, irreversible alcohol
phase separation occurred even after warming up to 85˚F which corroborates the study done
by Camina (1978). Anhydrous alcohol, on the other hand was homogenous and clear even at
30˚F. Bernardo (1978) also determined that incremental addition of water to as low as 0.1%
by volume to the Alcogas induced cloudiness and subsequent phase separation while in a 15
% anhydrous alcohol blend 0.9% of water will cause the same effect which accounts the
fuel’s sensitivity to contamination. Thus, hydrous alcohol has nine times greater water
tolerance compared to that of the hydrous. Bernardo (1978) evaluated the performance of the
use of the Alcogas mixture based on the acceptable motor fuel characteristics. These
characteristics include high power output and low specific fuel consumption good
54
startability, warm-up, and accelerability; freedom from vapor lock; non-corrosivity to metals;
non-deteriorating effects on sealants, fuel hoses etc.; knock-free properties; and nongumming tendencies. Results established the advantages and disadvantages of “hydrous”
alcohol blend to the engine performance. Among the disadvantages of using hydrous alcohol
is the effect of vapor lock. As Bernardo (1978) mentioned, vapor lock is a condition of partial
or complete stoppage of fuel flow caused by fuel vapor blockages in one or more segments of
the entire fuel system when temperature increases, particularly in the pump. The reduction of
speed and power of the engine is an effect of vapor lock. Completer vapor lock in the system
will cause a difficult engine re-start unless the fuel are cooled to reduced volume of vapor in
the system. It is because addition of a small amount of ethanol with gasoline decreases its
vapor pressure. Addition of alcohol, whose molecules are strongly bonded by hydrogen
bond, in a non-polar mixture such as gasoline causes hydrogen bonding to be less extensive
in which the alcohol molecules tends to behave more in keeping with its low molecular
weight making it more volatile. This in effect explains why the addition of ethanol to
gasoline causes disproportionate increase in vapor pressure and a depression of the boiling
point temperatures causing vapor lock. The Vapor lock Index (VLI) predicted using the Reid
Vapor Pressure (RCP) where 17.7 for Alcogas as to 12.9 of premium gasoline where
maximum VLI specification is at 14.0. This reduces that possible engine problems may
occur due to loss of vapor lock protection. Findings also showed that hydrous alcogas is
corrosive to certain types of metals such as ferrous and zinc. Hydrous alcogas, as well, is
incompatible with some type of rubbers and plastics which can be found in the sensitive fuel
parts that can affect its durability. Another disadvantage is the reduced energy content due to
the lower heating value of the alcogas when it is combusted. Bernardo (1978) pointed that
55
using ethanol as gasoline blend improves the anti-knock capability of the fuel, thus tetraethyl
lead content can be reduced. At present, tetraethyl lead is not anymore employed as antiknock because of the hazards that it can cause to public health. As response to the problem
developed in using hydrous ethanol as fuel blend, Bernardo recommended the modification
of fuel carbureting systems or the use of anhydrous fuel alcohol of 99.0% purity. The tests
results and findings derive the need to establish among the distillery industries a process that
will produce an anhydrous blend of ethanol.
Ethanol takes advantage in its high degree of compatibility with existing vehicle
technology. Tan et al. (2005) cited the work of Nadim et al. (2001) that evaluated the
performance of ethanol as fuel. This study reported that higher bioethanol concentrations
require engine modifications, particularly in the adjustment of fuel to air ratio. Because of its
high octane rating, spark-ignition engines designed specifically for bioethanol can have
higher compression ratios than the conventional unit. The 10% ethanol blending mandate by
the Biofuels Law of 2006 is the upper limit of ethanol blending without engine
modifications. Further, ethanol fuelled engine and ethanol-gasoline flexible engines are
already available in the market. Notions on the possible detrimental effects on engines of
long-term ethanol use still arise with stakeholders and vehicle manufacturers. Appendix E
presents the claims of manufacturers on ethanol as fuel blend.
3.7.2 Ethanol as Diesel Substitute and Additive
The Alcohol Fuel Program in the Philippines developed during the 1980’s promoted
the use of ethanol as gasoline fuel. Researches to diversify the application of ethanol as fuel
also emerge during this period. Among these researches is the use of ethanol in diesel engine.
56
Cruz and Sta. Ana (1978) assessed the use of ethanol and methanol as supplementary fuel for
diesel engines. In this study, alcohol was introduced into a diesel engine in the same manner,
and can be through a carburetor attached to the air-intake manifold. Alcohol has two distinct
properties that contribute to prevention of engine knock: (a) a high level of anti-knock quality
with octane numbers ranging from about 90 to 106: and (b) a high vaporative cooling effect
within the inlet manifold, and consequently a lower compression temperature which inhibits
pre-ignition. It was also determined that the thermal efficiency were lower for alcohol than
for straight diesel because of the high evaporative cooling effect of alcohol that results to
higher fuel injection. Further, the exhaust temperature were assessed to be significantly lower
that could promote lower levels of nitrogen oxide pollutants. Results also revealed that
ethanol is a better fuel than methanol because of the higher heating value of ethanol and
higher heat of evaporation of methanol. Cruz and Sta. Ana (1978) also emphasized the need
for engine modification on the application of alcohol for diesel engine.
Rudy Lantano developed an Alcodiesel fuel blend. This blend was evaluated on a
limited scale by the Central Azucarera Don Pedro (CADP) in Nasugbu, Batangas. Hydrous
ethanol of 95% purity was blended with 85% diesel fuel which was used by CADP trucks
and payloaders. In contrast to the study performed by Cruz et al. (1978), positive results were
obtained by Picornell (1989) without modification. However, results from the application of
alcodiesel were not conclusive specifically in fuel consumption and performance because of
biases on the part of the driver and errors in monitoring of consumption data. Among the
observations from the runs performed are the reduction of smoke emissions and cooler
operating temperature of engines even at high speed and great load. Picornell (1989)
mentioned that in the consumption of fuel, minimal savings were attained but it still needs to
57
be verified through a dynamometer test where all parameters involved for the test are under
control. Picornell (1989) also claimed that the alcodiesel blend produced when utilized in any
diesel engine exhibits comparable or even better performance with that of pure diesel, better
in the sense that the engine does not overheat especially at higher speed and greater load. The
high cetane index number of alcodiesel facilitates smooth combustion and provides easy
starting. The relatively high latent heat of vaporization of alcohol also serves to cool all-fuel
mixture, thus, limiting the possibility for engine to overheat. Picornell (1989) recommends to
conduct further testing to determine the adverse effects on engine particularly the injection
pump plunger and cylinder liner and to provide a bench dynamometer to determine the fuel
consumption and optimum engine brake horsepower.
3.8 Environmental Impacts of Ethanol Production and Application
The production of ethanol alcohol will involve the generation of wastewater which
will definitely affect the quality of the receiving body of water if this is not adequately
treated before disposal. Based on experience, to produce 1 part of ethanol, 12 parts of
wastewater will be generated in the process. Thus, the main problem therefore, is how to treat
this high biological oxygen demand (BOD) containing wastewater (DENR-EMB, 1989).
According to the DENR-EMB (1989), the combustion of an ethanol-gasoline
blended fuel will increase the emission of hydrocarbons in the form of aldehydes. Aldehyde
is a known carcinogen and a contributor to the formation of photochemical smog. This is in
addition to the usual primary pollutants such as carbon dioxide, sulfuric dioxide, nitrogen
oxide and particulates emitted in present day gasoline. Based on the chemical reaction
between alcohol and gasoline it is evident that there will be an increase in carbon monoxide
58
and hydrocarbon. But according to them, hydrocarbons or aldehydes can be controlled easily
by using catalytic converters.
Contradicting by using GREET (Greenhouse Gases, Regulated Emissions, and
Energy Use in Transportation), a public-domain life-cycle inventory model for simulating a
wide range of existing and anticipated energy vectors for automotive transport, the study of
Tan and Culaba (2002) presented the life-cycle air emissions of E10 and gasoline. The study
shows that VOC, CO and SOx emissions are 15-20% lower for E10 than for gasoline while
NOx and PM10 emissions are slightly higher for E10. For the tailpipe emissions from
vehicle operation, the results show that significant reductions in VOC, CO and SOx
emissions for E10 in place of gasoline. According to them, improved combustion due to the
oxygen content of E10 reduces both VOC and CO exhaust emissions. Bioethanol is virtually
sulfur-free, blending in E10 automatically reduces SOx by about 10%. Vehicle PM10 and
NOx emissions are virtually identical for the two fuels.
The life-cycle emissions of
greenhouse gases were also predicted. The results show that the use of E10 gives reductions
of 6% for CH4 and 11% for CO2, while upstream combustion of biomass in ethanol
production results in a net increase of 12% in N2O emissions. And because carbon dioxide
accounts for 94-95% of global warming potential (GWP), the effects of CH4 and N2O
emissions are almost negligible. Thus, E10 yields an 11% reduction in total greenhouse
gases compared to conventional gasoline.
There are also reductions in CH4 and CO2
emissions resulting from vehicle operation, while N2O emissions of the two fuels are
identical.
Tan et al. (2005) mentioned the significant reductions in both vehicular and life
cycle air emissions result from the use of ethanol in gasoline blends which at some point
59
depend on blending ratio. Air emission characteristics are summarized in Table 3.7. Tan et
al. (2005) noted the following exceptions:
•
Increase in emission of some VOC (Volatile Organic Compound) species particularly
acetaldehyde
•
Mixed results for NOx emissions with different studies predicting results ranging
from marked decrease to slight increase.
Table 3.7. Effect of Air Blending on Air Emissions Relative to Gasoline Baseline
Emission
Description
End Effects
Tailpipe
Life Cycle
Volatile organic
Smog formation
Decrease for
Decrease for
VOC
compounds
and toxicity
most species
most species
Smog formation
Decrease
Decrease
CO
Carbon monoxide
and toxicity
Smog formation
NOx
Nitrogen oxide
and toxicity and
Inconclusive
Inconclusive
acid rain
Decrease
PM10
Particulate matter
Health impacts
Decrease
SO2
Sulfur dioxide
Greenhouse gases
(CO2, CH4, and
N2O)
Source: Tan et al. (2005)
Total
GHGs
Acid rain
Decrease
Climate change
Decrease
Decrease
Decrease
3.9 Summary and Conclusions
Bioethanol, as defined by the Biofuels Act of 2006, RA 9367, is ethanol produced
from different feedstock and biomass. The act mandates the ethanol blend of 5% to 10% into
gasoline to promote the reduction of oil imports, improvement of environmental conditions,
and rural employment. Relatively, to meet the provisions on ethanol blending with gasoline
products there must be enough supply of locally produced ethanol to achieve energy security
60
and to stabilize its price. This implies the need of increasing the local production of ethanol.
In accordance to this act, the government developed an Ethanol Program granting
opportunities to industries and distilleries to develop and to improve the process of
production of ethanol. The program also encourages researches to find for alternative ways to
develop the production of ethanol in the country.
The Philippines knowledge on the use of ethanol as fuel has long been established.
It started during the World War II when the Philippines supply of oil from exporting
countries was cut-off. It was the Armed Forces of the Philippines (AFP) who spearheaded the
studies in the assessment of ethanol as fuel. This was continued during the term of President
Marcos as he directed to search for alternative fuels from indigenous materials. The directive
was triggered by the oil price hike during that period. Many studies on the production of
ethanol that revolves on the selection of materials, effective microorganisms and
fermentation systems were conducted. There were also studies on the assessment of ethanol
as gasoline and diesel substitute or additive. The study for the use of ethanol was
discontinued during the late 1980’s because of the stabilization of oil price. At present,
ethanol studies are in resurgence due to the increased ethanol demand brought about by the
Biofuels Act of 2006.
Ethanol was found to be a viable alternative for gasoline. Maximum blending
concentration for ethanol was established at 10% ethanol blend for unmodified engines.
Application on diesel engine does not clearly give positive results due to the deviations in
diesel properties.
Bioethanol is produced from sugar bearing materials, starches, celluloses, and
hemicelluloses. The Philippines has a wide variety of these resource materials that could be
61
used for ethanol production such as sugarcane, corn, sweet sorghum and cassava. Sugarcane
crop is still the most preferred feedstock for bioethanol production in the Philippines because
of the reduced production cost. Though, it does not mean that it is the only economically
viable source of bioethanol. There are other potentially available feedstocks in the country
that must be explored and examined.
Large demand for bioethanol will be expected to emerge on the following years
from the implementation of the Biofuels Act. This will eventually cause the increase of the
price of bioethanol and the competing products from sugarcane if only sugarcane is used as
feedstock. This will also mean a larger land requirement for agricultural utilization. With the
advent growth of population and occurrence of urbanization come larger land, food and
energy requirement. The fact that the country’s land area will always be constant on the
following years will result to scarcity and price hikes. Conversely, energy security is another
direction of the Biofuels Act of 2006. Thus, it is important to secure availability and stability
of supply of raw materials. Diversification of ethanol feedstock must be considered to
provide supply and price stability of the ethanol fuel. The use of locally available feedstock
which does not affect food supply on commercial scale must be considered in the selection of
raw materials. Many studies on different raw materials for ethanol production were already
conducted in the country. However, these studies do not identify which feedstock is the most
economically and industrially viable. Comparative economic and energy evaluation and
assessment of the processing of these feedstocks for bioethanol production must be
conducted to determine which among the feedstocks could give the most optimal yield must
be conducted.
62
Ethanol productivity can also be improved by increasing plant yield and decreasing
plant propagation period. Biotechnology is an evolving technology that renders enhancement
on the genetic make-up of an organism.
Most studies in the Philippines centered on
enhancing ethanol productivity by improving the process of production. However, integration
of biotechnology to crop seeds could have more extensive enrichment on ethanol
productivity. Developing hybrids that could grow in shorter period would mean increase in
crop cultivation. Moreover, the development of a more productive plant of higher
carbohydrate content could be a potent enhancement for higher ethanol production.
The potential of cellulose as bioethanol source was also determined from the
studies. The processing of cellulose into ethanol is not yet a well establish path. Technologies
on the improve production of ethanol from cellulose will definitely boost the ethanol supply
on the countryside since large amount of cellulose are available in the country and most are
incurred as waste materials. The use of cellulose as feedstock for ethanol could be the most
positive answer for the future crop supply crisis since cellulose are non-food materials. The
conversion of cellulose materials into ethanol must be further investigated and developed so
that the production will become economically competitive and feasible.
Bioethanol can be produced from the conversion of biomass through fermentation.
Microorganisms are involved in the conversion of biomass into ethanol.
Different
microorganisms are able to utilize different biomass and convert it to ethanol. Biomass
conversion into ethanol is strain and substrate specific. For saccharine compounds, direct
fermentation using Saccharomyces and Zymomonas genera were intensively studied. Strains
of Saccharomyces cerevisiae and Zymomonas mobilis that can produce ethanol more
63
efficiently were already developed. Studies on the use of other microorganisms for
fermentation were also conducted and ethanol efficiencies were also evaluated.
Enzymatic process of the conversion of starchy materials into fermentable glucose
through hydrolysis is more favorable than acid hydrolysis.
Amylase producing
microorganisms are involved in this process. The Bacillus genus is the well-known amylase
producing bacteria. However, a comparative amylase producing ability of the Bacillus
species were not yet evaluated. Streptococcus bovis were also found to be amylase producers
and that its amylase has higher hydrolytic activity than other bacterial amylases.
The
improvement of the conversion of starch is dependent on the amylase producing ability of the
microorganisms used, it is therefore necessary to conduct a comparative evaluation of the
amylase producing abilities of these bacterial amylases. Genetic manipulations of these
microorganisms can give also an advantage on improving its performance. Schwanniomyces
alluvius was also determined to ferment starchy materials into ethanol but its performance on
industrial production was not evaluated.
Acid hydrolysis of cellulose for ethanol production is more preferred than enzymatic
hydrolysis. Studies on the use of cellulase producing microorganisms like Trichoderma
viride discovery of highly cellulytic microorganisms and genetic improvement of existing
cellulase producers can help developed a more competitive cellulose-to-ethanol conversion
After fermentation, separation and purification processes are needed to produce
ethanol for fuel use (anhydrous ethanol). Distillation is the most common method for the
separation and purification process and usually it is energy intensive. The ethanol produced
after distillation cannot be directly utilized because of the moisture retained which is
equivalent to the azeotropic concentration. Anhydrous ethanol production will require the
64
addition of another purification stage. Many patented technologies and processes were
already developed to dehydrate ethanol and achieved fuel grade purity. However, there is still
a need to determine which among these technologies the is most cost-effective means of
producing ethanol and what improvement can be made or integrated in the process.
The development of environmental friendly technologies for bioethanol production
also needs consideration. Many waste materials are incurred from harvesting to ethanol
processing. The primary problem in ethanol production from sugarcane is the wastewater
produced from distillery slops. Several studies focused on the utilization of the distillery
slops into fertilizer, as a substrate for methane production, and also utilizing a part of the
distillery slop for alcohol production. A study on the utilization of distillery slop as
supplement for ethanol production was conducted but the application of industrial systems on
yeast culture was not considered.
Chapter 4
RECOMMENDATIONS
Based on the considerations arising from the current knowledge on biodiesel and
bioethanol priority areas for scientific research and technology development were identified
and the following studies are recommended:
4. 1
Biodiesel
•
Selection of other potential feedstock for biodiesel production. A potential feedstock
for biodiesel production is a high yielding-oil plant. The oil that must be derived
must also be good characteristics because some of the biodiesel properties were
inherent to the plant oil such as percent saturation or percent unsaturation, fatty acid
carbon chain length, and may affect the fuel’s kinematic viscosity, oxidative stability,
solvency, and lubricity.
•
Oil extraction operation. Different raw materials containing oil to be extracted for
biodiesel production have its suitable process of extraction. Comparative analysis
with the methodology must be done to determine the most suitable extraction
operation for the selected feedstock. Currently, the oil used for the esterification
process should be refined and oil extraction operation has several effects on the
quality extracted oil.
•
Production of methanol. Methanol is used to esterify the fatty acid and is fed and
reacted in excess. With a large demand for biodiesel, large amount of methanol is
also to be considered. A study on the production of methanol is also recommended.
65
66
•
Ethanol for transesterification process. Methanol is a toxic compound and probably
will become insufficient for the future demand on biodiesel production. Ethanol can
also be used to react with fatty acid to produce biodiesel. Large production of ethanol
(bioethanol) is also a project of the government. A possible area to be investigated is
the kinetics of ethanol in transesterification reaction that must be comparable with
methanol. An initial study was done by Demafelis.
•
Transesterication process and reactor design. Currently, refined oil is used to react
with methanol to produce the fatty acid methyl ester. As recommended by Mr. Glenn
Apostol, chemist of Chemrez, Inc., a study in utilizing crude oil instead of refined oil
in esterification process must be done to lessen raw material cost. Esterification
process is the heart of the biodiesel production. There are several esterification
processes that can be used in biodiesel production. A need for a research can be
focused on process integration or modification in improving the process for biodiesel
application. Research and development in biodiesel industries focused on the process
optimization with can also be a topic for an academe research.
•
By-products utilization. Glycerol is the main by-product of biodiesel production.
Purification or refining of glycerol must also be studied. There will also be an
increased production of glycerol as biodiesel production is increased. The price of
glycerol was not competitive but it can be converted to other highly priced chemicals.
Glycerol can be used as a raw material for the production of propylene glycol, which
also has a wide variety of applications.
•
Increased productivity of oil plant source. Genetic modification of the plant source
resulting in a shorter harvest period and higher oil yields must also be studied.
67
•
Comparative study of different feedstock for biodiesel production. Different
feedstock will result to different biodiesel characteristics. Comparison between the
different biodiesels from different raw materials will be helpful to determine the best
material for biodiesel application.
•
Blending of biodiesels derived from different sources. Some properties of a biodiesel
can be enhanced by blending it with another biodiesel. The effect of blending
different biodiesels at varying proportions must be investigated.
•
Comparative study between fatty acid methyl ester with other fatty acid alkyl ester.
There are studies in producing biodiesel using other alcohols like ethanol aside from
methanol. Comparative analysis between the properties of the biodiesel produced
using different alcohols is recommended to be studied.
4.2
Bioethanol
•
Selection of economically and industrially viable feedstock. Diversification of
effective feedstock for ethanol must be considered to accommodate the future
increase of ethanol demand.
a. A comparative study of economically viable raw materials for alcohol
production using the present cost of fermentable material contained in the raw
materials must be done
•
Feedstock productivity enhancement. Increasing crop productivity by developing
hybrids with shorter harvesting period must be investigated. Another area to be
considered is the genetic engineering of feedstock to increase the ethanol yield.
68
•
Selection and genetic modifications of microorganisms used in fermentation.
Selection of the best performing enzymes, yeast and bacterial strains and evaluation
of favorable conditions for microorganism culture and production such as ethanol
tolerance and temperature. Genetic modification of microorganisms to improve
ethanol production must be performed. The following are suggested:
a. Comparison of amylase producing-ability of all the amylase producing
Bacillus species
b. Comparison of amylase producing ability of S. bovis with Bacillus species
c. Improvement of the cellulase producing ability of Trichoderma viride
d. Investigation on the use of either a flocculant yeast strain or yeast
immobilized on solid support using A. awamori
e. A preliminary study on using Schwanniomyces alluvius in large scale
production
f. Improvement of strains using more modern techniques
•
Development of cellulose-to-ethanol processes. Diversification of feedstock from
food crops into non-food source could be done by using cellulose-based substrates.
However, cellulose-to-ethanol conversion processes are not yet well-established. The
optimization of the conditions on cellulose pretreatment process must be considered.
•
Recovery of ethanol production waste. Large amount of waste and wastewater are
generated in the production of ethanol from crop reaping up to the fermentation
process. Detrimental effects on the environment will eventually arise in the long run
from these waste and wastewater.
69
a. The use of unsterile media in yeast culture and optimization of fermentation
conditions in distillery slops supplemented ethanol production medium
•
To conduct a process integration study in the cost-effective separation-purification
processes for fuel-ethanol applications through
a. Application of membrane technology
b. Integration of fermentation and separation for reduction of product inhibition
The key role that process design plays during the development of costeffective technologies is recognized through the analysis of major
trends in process synthesis, modeling, simulation and optimization
related to ethanol production.
REFERENCES
Arida, V.P., A.T. Atienza, and F.C. Borlaza (1984). Diesel Fuel Substitute from Coconut Oil
and Process of Manufacture. NSTA Technology Journal, (July-Sept. ed.),73-79.
Arida, V.P., A.T. Atienza, F.C. Borlaza and D.L. Binlayo (1981, December). Production and
Development of a Diesel Fuel Substitute from Coconut. Philippine Journal of Coconut
Studies, Vol. 6 no. 2, 10-20.
Armas, A. Jr. and D.J. Cryde (1984). Economic Evaluation of the Philippine Alcogas and
Cocodiesel Programs [Monograph]. Philippine Institute for Development Studies, 3, ISSN
0115-9194.
Bandapatan, M. S. B. (2003). Enzymatic Extraction of Soybean Oil for Biodiesel Production.
Undergraduate Research. College of Engineering and Agro-Industrial Technology.
University of the Philippines- Los Baños.
Bathan, E. M. (2000) Solvent Extraction of Oil from Shin Pulp. Undegraduate Research.
College of Engineering and Agro-Industrial Technology. University of the Philippines-Los
Baños.
Bawagan, B.O. (1977). Industrial Alcohol from Wood and Agricultural Residue. [Literature
Review]. FORPRIDECOM, no. 176.
Bernardo, R.S. (1978). An Evaluation of “Hydrous” Alcohol as Motor Fuel. Proceedings on
the Symposium on Alcohol as Motor Fuel. National Research Council of the Philippines,
Bulettin No.71.
Bugante, E.C., C.G. Alfafara, and F.R. Nayve, Jr. (1986). Single- and Two-Phase
Fermentation of Slop Waste Under Mesophilic and Thermophilic Conditions. Proceedings of
the Asia-Pacific Biotechnology Congress, Biotechnology for Agro-Industrial Progress.
Bugarin, R.M.B., D. M. Alba, and E. J. del Rosario (1983). Two-Stage Process of Ethanol
Production from Sweet Potato Flour and Rice Bran Using Aspergillus awamori and
Immobilized Yeast. Philippine Journal of Science, Volume 116 (2), 205-213.
Bulan, C. A. (unpublished). Biodiesel as an Alternative Fuel Leading to Cleaner
Environment, Chemical and Mineral Division-Industrial Technology Development Institute.
Department of Science and Technology, Unpublished Report.
Camina, E. (1978). Alcohol as Fuel for Gasoline Engine. Proceedings on the Symposium on
Alcohol as Motor Fuel. National Research Council of the Philippines, Bulettin No.71.
Carandang, E.V., M.L.M. Ferrer, and V.P. Red (1998). Use of 100% Coconut Methyl Ester
as Substitute for Diesel. PJCS, Volume 16 (1) ,22-25.
70
71
Co, C.E.T. (2007). Biodiesel Production from Coconut Oil and Methanol Using
Heterogenous Anionic Exchange Resin Catalyst in a Packed Bed Reactor. Thesis Proposal.
De La Salle University Manila.
Berba, F., Cruz, I., & Siochi, A. (Eds.). (1991). Coconut Fuel Blends Are Viable. (1991,
October-December). “PROGRESS”-PCIERD newsletter, Vol. 7, no. 2, 1-2 & 8.
Cook, J. (1983). Production Thermal Efficiency of Coconut Oil as a Compression Ignition
Fuel. [Research Report]. Townsville, Aus: University of North Queensland, Vol. 76 No. 9.
Retrieved July 1983, from http://www.Kokonutpacific.com.au.
Cruz, I. E. and F. B. Sta. Ana (1978), Alcohol as Supplementary Fuel for Diesel Engines.
Proceedings on the Symposium on Alcohol as Motor Fuel. National Research Council of the
Philippines, Bulettin No.71.
Dela Cruz, R. T. (2004). ICRISAT, DA- BAR Promote Production of Sweet Sorghum for
Ethanol Use [News report]. BAR Chronicle. Bureau of Agricultural Research. Department of
Agriculture, Volume 5 No. 8, 7.
Dela Gente, J. J. B. (1983). Manufacturing Diesel Fuel Substitute from Vegetable Oil. NSTA
Technology Journal, 75-80.
Dela Paz, A.A.(1983). Production and Development of a Diesel Fuel Substitute from
Coconut. Philippine Journal of Coconut Studies, January-March ed., 53-59.
Del Rosario, E.J. (1978). Production of Sugar and Alcohol from Cellulosic Materials.
Proceedings on the Symposium on Alcohol as Motor Fuel. National Research Council of the
Philippines, Bulletin No. 71.
Del Rosario, E.J. (undated). Status and Assessment of Current Technologies on Alternative
Crop Sources of Energy. Philippine Journal of Crop Science. Vol.5, no.2, 67-74.
Del Rosario, E.J. (1982). Biotechnological Research Applied to the Utilization of Some
Coconut By-Products. Coconut By-Product Utilization and Socio-Economic Research.
PCARRD.
Del Rosario, E. J. (1982). Fuels Alcohol from Agricultural Crops and Residues .
Proceedings of the Regional Workshop on the Technology of Fuel Alcohol Production.
University of the Philippines- Los Baños.
Del Rosario, E.J. (1983). Sugar and Alcohol from Fermented Rice Straw. Based on the paper
entitled “Saccharification and Ethanol Fermentation of Rice Straw” presented in the
UNESCO-FEISEAP Workshop on Rice Straw Utilization and Technology, UP-Los Baños,
Laguna.
Del Rosario, E.J. and R. Wong (1984). Conversion of Dextrinized Cassava Starch into
Ethanol Using Cultures of Aspergillus awamori and Saccharomyces cerevisiae. Enzyme
Microbiological Technology, Volume 6, 60-64.
72
Del Rosario, E.J., V. Santisopasri and R.M. Matanguihan (1981). Continuous-flow
Fermentation of Sugarcane Molasses into Ethanol in Tubular Fermenters. Paper presented at
the 28th PHILSUTECH Convention, Iloilo, Philippines.
DENR (1989-1993). Position Paper of the Alcohol Advising Group on the House Bills
Providing for the Use of Alcohol as Octane Enhancer in Place of Tetraethyl Lead in
Gasoline. Philsutech, Unpublished Report.
Department of Environment and Natural Resources – Environmental Management Bureau
(1989). Environmental Impact Assessment on the Use of Ethanol as Substitute for Lead in
Motor Gasoline. Paper presented at the 28th PHILSUTECH Convention, Iloilo, Philippines.
Diamante, J.A.R., M.C. Tan and L.R.C. Yan (2007). A Comparison of Strong Base AnionExchange Resins and Sodium Hydroxide as the Catalyzing Agent in the Transesterification
of Food Grade Philippine Coconut Oil. Thesis Proposal. De La Salle University-Manila.
Diaz, Jr. R.S. and F.C. Galindo (undated). Coco-Biodiesel – A Perfect Natural Diesel. Asian
Institute of Petroleum Studies, Inc., Unpublished Report.
Diaz, R.S. (undated). Coconut for Clean Air. Asian Institute of Petroleum Studies, Inc.,
Unpublished Report.
DOE Lays Down Long-Term Alternative Fuels Program to Address Rising Oil Prices.
(2005). [Press Release]. Retrieved July 20, 2005, from http://www.doe.gov.ph/press/.
Domingo, D.S. and Cruz, E.E. (1982). Fuel Adapted as a Substitute for the Diesel Engine
Operation. NSTA Technology Journal, Jan-Mar 1982, 65-69.
Elegado, F.B., E.R. Mendoza, and C.B. Pham (1990). Simultaneous Saccharification and
Fermentation of Raw Starch with Ethanol Stripping and Rectification. Philippine Journal of
Science, Vol. 119 No. 3, 205-222.
Escarilla, M.L.T., M.F.T. Logrono and T. O. Macuro (1993). Evaluation of Yeast Strains
for Biomass Production from Cane Molasses. Proceedings on the 40th Annual Convention of
the PHILSUTECH, Bacolod City.
Fernandez, W.L. (1977). Alcoholic Beverages from Coconut Sap. [News Article]. Coconuts
Today, 92-96.
Floresca, R. (1981). Alcohol from Tuba and Guavas [News Article]. Philippine Farmers’
Journal (May 1981 issue). 6-7.
Gosiengfiao, A. P. (2003). Solvent Extraction and Transesterification of Soybean Oil for
Biodiesel Production. Undergraduate Research. College of Engineering and Agro-Industrial
Technology. University of the Philippines-Los Baños.
Halos, S. C. (1982). Microbial Aspects of Alcohol Production: Yeast and Fungi. Proceedings
of the Regional Workshop on the Technology of Fuel Alcohol Production. University of the
Philippines- Los Baños.
73
Hayashida, S. (1982). Enzymatic Saccharification of Raw Starch and Its Application to the
Production of Ethanol. Proceedings of the Regional Workshop on the Technology of Fuel
Alcohol Production. University of the Philippines-Los Baños.
Hernandez, M.E.E. (2007). DA-BAR, ICRISAT, and UPLB Sign MOU for Sweet Sorghum
Project [News report]. BAR Chronicle. Bureau of Agricultural Research. Department of
Agriculture. Volume No. 8 No. 2.
Joson, L.M. (1978). Alcohol Production from Starchy Materials. Proceedings on the
Symposium on Alcohol as Motor Fuel, National Research Council of the Philippines,
Bulletin No. 71.
Lirag, R., Jr and R. Umali (1980). Pre-feasibility Studies on the Use of Nypa Fruticans as
Alcohol Source to Fuel Fishing Boats. A Joint Project of the Natural Resources Management
Center and Center for Development Studies, Unpublished Report.
Magbanua, J.P.V., M.L.F. Paje, M.L.Q. Sison, E.C. Bugante, F.G. Torres, V.P. Migo, F.R.P.
Nayve, M. Yabes, M.J. Papa and W.L. Fernandez (2000). Utilization of Distillery Effluent as
Fertilizer for Sugarcane. Unpublished Research.
Parkash, K. and M. Paramathma (2006). Feasibility Study for the Production and Processing
of Biodiesel in the Philippines. Unpublished Report, Food and Agricultural Organization,
Manila, Philippines.
Pascual, L.M. and Tan, R.R. (2004). Comparative Life Cycle Assessment of Coconut
Biodiesel and Conventional Diesel for Philippine Automotive Transportation and Industrial
Boiler Application, Conference Paper.
Picornell, R. J. A. (1989). Alcodiesel Fuel: Central Azucarera Don Pedro’s Experience.
Transportation and Cane Handling Division Unpublished manuscript, PHILSUTECH
Convention.
Primer on the Department of Energy’s Alternative Fuels Program-Web/FAQs. (2006). [News
Report]. Retrieved May 6, 2006, from http://www.doe.gov.ph.
Quinones, N.C. and M.V.A. Bravo (1996). Hydrocarbon-Producing Plants: Alternatives to
Pure Diesel. CANOPY International, Nov-Dec 1996.
Raymundo, A. K. (1982). Bacteria Involved in Alcohol Production. Proceedings of the
Regional Workshop on the Technology of Fuel Alcohol Production. University of the
Philippines- Los Baños.
Reyes, N.O. (late 1970’s). Coco-oil Can be Processed into Fuel. Philippine Farmer’s
Journal, October ed., 16-17
Rivera, G. Jr., R. Bihis and L. Aventino (1977). Alcohol for Motor Fuel and Its Production
from Raw Sugar, Cane Juice, and Molasses. [Excerpt based on “Alcohol for motor fuel and
74
its production from raw sugar, cane juice, and molasses”]. In N. Chinjen, R. Balasico & A.
Garan (Eds.), Blackgold (pp. 2-7). Diliman, Quezon City: Philippine Sugar Institute’s
Industrial Research and Development Office.
Rogers, P. L. (1982) Kinetic Evaluation of Zymomonas mobilis in Continuous Culture.
Proceedings of the Regional Workshop on the Technology of Fuel Alcohol Production.
University of the Philippines- Los Baños.
Rogers, P.L., K. J. Lee, J. H. Lee, M. L. Skotnicki, R. J. Pagan and D. E. Tribe (1982). The
Zymomonas Process for Ethanol Production. Proceedings of the Regional Workshop on the
Technology of Fuel Alcohol Production. University of the Philippines- Los Baños.
Saludo, C., B. de Jesus, C. Lim, E. Quidilla and E. Siman (1977). Butanol from Molasses.
[News Article]. Crystallizer, 11-22.
Secreto, N. C. (2005). Evaluation of Distillery Slops as Medium Component in MolassesBased Ethanol Fermentation Using Biotech Yeast Strains. Undergraduate Research. College
of Engineering and Agro-Industrial Technology. University of the Philippines-Los Baños.
Sumera, F.C. and Sadain, S. (1990). Diesel Fuel by Kolbe Electrolysis of Potassium of Salts
of Coconut Fatty Acids and Acetic Acids. Philippine Journal of Science, Vol. 119 No. 4,
333-345.
Taguchi, H. (1982). Recent Topics of Ethanol Fermentation in Japanese Institutions.
Proceedings of the Regional Workshop on the Technology of Fuel Alcohol Production.
University of the Philippines- Los Baños.
Tan, R.R. and A.B. Culaba (2002). Life-Cycle Environmental Benefits of Using Bioethanol
as a Gasoline Additive. Philippine Engineering Journal, Vol. 23(1):45-58.
Tan, R.R., A. B. Culaba, and M.R.I. Purvis (2002). Application of Possibility Theory in the
Life-Cycle Inventory Assessment of Biofuels. International Journal of Energy Research
2002; 26: 737-745 (DOI: 10.1002/er.812).
Tan, R.R., A. B. Culaba, and M. R. I. Purvis (2004). Carbon Balance Implications of
Coconut Biodiesel Utilization in the Philippine Automotive Transport Sector. Elsevier.
Biomass and Bioenergy Journal, 26 (2004) 579-585.
Tan, R.R. (2004). Comparative Life-Cycle Analysis of the Bioethanol and Biomethanol
Pathways for Recycling Solid Waste Into Liquid Fuel. Final Report to the URCO Project No.
04 RP, Unpulished Report.
Tan, R.R., A.B. Culaba, and M.R.I. Purvis (2002). Land Use and Carbon Balance
Implications of Coconut Biodiesel Utilization in the Philippine Automotive Transport Sector.
Proceedings of the 3rd Pacific Asia Conference on Mechanical Engineering (3 PACME).
Tan, R. R., A. B. Culaba, J. Tanchuco, A. Fillone and M. P. Ang (2005). Techno-Economic
Assessment of Ethanol as an Alternaitve Transportation Fuel. Final Report to the Sustainable
75
Energy Development Program. Center for Engineering & Sustainable Development
Research, De La Salle University-Manila, Unpublished Report.
Teodoro, A.L. (1931). Effect of Variable Compression Ratio on Performance of Tractor
Engines Using Ethyl Alcohol. University of the Philippines Natural and Applied Science
Bulletin 1, 187-221.
Tongson, G. M. (2006). Saccharification and Fermentation of Corn (Zea Mays) Waste
Mixtures for Ethanol Production. Undergraduate Research. College of Engineering and
Agro-Industrial Technology. University of the Philippines-Los Baños.
Vachha R. (2007). ICRISAT Promotes Ethanol from Sweet Sorghum in the Philippines
ICRISAT Happenings, In House Newsletter of the International Crops Research Institute for
Semi-Arid Tropics, Unpublished manuscript No. 1242.
Villanueva, M.R. (1980). Rootcrops and the Energy Crisis. [Newsletter Article]. RADIX, 3-5.
Wong R. L. (1982). Conversion of Pre-Treated Cassava (Manihot esculenta Crantz) Root
Flour into Ethanol Using Cultures of Aspergillus awamori and Saccharomyces cerevisiae,
Unpublished M. S. Thesis at UPLB.
Yoshida, K., F.Argamosa, R. Hizon, and C. Zapanta(2004). Effect of Blending Low Sulfur
Diesel Fuel with Coconut Methyl Ester on the Engine Performance Characteristics of a
Single Cylinder , 4 Stroke Diesel Engine. Philippine Journal of Industrial Education and
Technology, Volume 14 (1),15-27.
APPENDICES
APPENDIX A
Hydrocarbon-Producing Plants: Alternatives to Pure Diesel
Family/Species
1. Euphorbiaceae
Aleurites molucanna
Aleurites trisperma Blanco
2. Guttiferae
Calophyllum inophyllum
3. Placourtiaceae
Pangiumegule spp.
4. Lecythidaceae
Bartingtonia asistica L.
5. Pittosporaceae
Pittosporum resiniferum Hems.
6. Sapindaceae
Ganophyllum ralcatum Blume
Nephelium mutabile Blume
7. Myrtaceae
Eucalyptus spp.
8. Moraceae
Ficus spp.
Common
Name
Plant Material
Yield
Hydrocarbon
Extract
lumbang
oil from seeds
-
bagui-lumbang
-
1 seed=34% kernel
w/c consist of 52% oil
-
bitaog;
palomaria
oil from seeds
6 kg of fresh seeds =
1 liter oil
-
pangi
oil from seeds
seeds yield 50% oil
-
NSTA, 1982
botong
oil from seeds
-
-
NSTA, 1982
Heptane;
Dihydroterpene
Halos, 1980;
NSTA, 1982;
Noble, 1983;
Costales, 1991
Reference/Author
NSTA, 1982
Dating, 1979
-
hanga;
petroleum
nut
oil from seeds
1 seed = 2-3 ml of oil
aranger
bulala
oil from seeds
oil from seeds
oil is 64% of seed
dryweight
bagras; gum
tree
oil from leaves
1 ton of leaves =
2-51 kg oil
O-cymene
fig tree
latex from
stumps
-
-
-
NSTA, 1982
NSTA, 1982
Gerarde, 1960
NSTA, 1982
77
84
Plant Material
Yield
Hydrocarbon
Extract
Reference/Author
oleoresin
from stumps
1 tree yields 232671 g of oleoresein/
week
Pinene;
Limonen
Gerarde, 1960;
Noble, 1979;
NSTA, 1982
almaciga
resin from
stumps
1 tree yields 16-20 kg
of copal/year
Dipentene;
B-pinene;
Camphene
NSTA, 1982
11. Burseraceae
Canarium ovatum Ergl.
pili
resin from
bark
1 tree yields 45 kg
resin/year
D-pinene
NSTA, 1982
12. Caesalpiniaceae
Dipterocarpus spp.
supa
oil from
sapwood
1 tree yields 10 L
of oil/year
-
NSTA, 1982
dipterocarps
oil from
sapwood
1 tree = 1 kg of
sap/day
-
Dating, 1979;
NSTA, 1982
layeng;
rapetek
outer bark
-
-
Rojo, 1979;
Dating, 1982
Family/Species
9. Pinaceae
Pinus insularis Endl.
10. Araucariaceae
Agathis dammaraa Lamb.
13. Dipterocarpaceae
Dipterocarpus spp.
14. Celastraceae
Kokoona ochracea (Elm.)
Merr.
Common
Name
Benguet pine
78
85
Family/Species
15. Euphorbiaceae
Euphorbia lacteal Haw.
16. Euphorbiaceae
Euphorbia tirucalli L.
Jatropha curcas L.
Ricinus communis L.
17. Buxaceae
Simmondsia chinnensis
Scheider
18. Celastraceae
Celastrus paniculata Wild.
Source: Quinones and Bravo (1996)
Common
Name
Plant Material
Yield
Hydrocarbon
Reference/Author
Extract
mottled
candlestick
plant sap
8% of plant weight
-
NSTA, 1982
pobreng kahoy
lubang bakod
castor bean
plant sap
sap; seeds
oil from seeds
6.12% of plant weight
63.05% oil from kernel
46-53% oil from seeds
-
NSTA, 1982
NSTA, 1982
Redolosa, 1982
jojoba
oil from seeds
52% oil in seeds
-
NSTA, 1982
bilogol; lagete
seeds; plant sap
45% oil in seeds
-
NSTA, 1982
79
86
APPENDIX B
Comparison of Batch and Continuous Alcoholic Fermentation by Yeast
Process
and
Features
MelleConventional
Bionot
Process
Process
(Batch)
(Batch)
Cell
concentration,
2-3
g/l
Final ethanol
concentration,
100-110
g/l
Yield from
85-86
sugars, %
Ethanol
productivity,
1.3-2.5
g/l/h
Fermentation
retention
70-76
time, h
Source: DENR (1989)
ITDI
Immobilized
ITDI
ITDI
HOPAF
Column
SCSTR
Yeast Cells
Vertical
Horizontal
Reactor
in CDIC
Tubular
Fermenter
Tubular
Process
Single Stage
(SemiReactor
Fermenter (Continuous)
Fermenter
(Continuous)
(Continuous)
Continuous) (Continuous) (Continuous)
9.6
20
56
125
150
68
125
55-80
99
85
63.8
61.3
58.6
106.2
85-86
90
90
83
80
77
88.8
6
13.0
23
58.1
37.76
25
36.6
15-25
7
2-6
1.10
1.64
2.0
2.7
80
87
APPENDIX C
Summary of Fermentation Systems and Processes
System/
Process
Feedstock
Traditional
batch
molasses
Melle-Boinot
molasses
Alcon (U.K.)
sugarcane
juice
BIOTECH
Process 1
Molasses
BIOTECH
Process 2
Molasses
BIOTECH
Process 3
Molasses
NIST Process
I
Laboratory
Molasses
Organism
S. cerevisiae
Magnae strain
S. cerevisiae
(with recycle)
S. cerevisiae
(flocculent)
S. diastaticus
(flocculent)
S. cerevisiae
(heat-tolerant
immobilized on
wood particles)
S. cerevisiae
(heat-tolerant
immobilized on
carrageenan)
S. cerevisiae &
S. diastaticus
(F9-5)
Residence
Time (h)
Sugar
Concentration
Initial
Final
(g/l)
(g/l)
Yeast
Concentration
(g/l)
(cells/ml)
Ethanol
concn.
(g/l)
Volumetric
productivity
(g/l-h)
24
120
32
1
108
50
2.0
12 (total
cycle time)
130
--
1
108
60
5.0
7
100
2
3
4x108
67
9.6
4
220
36
30
4x109
72
18
7
200
50
15
2x109
60
8.6
6
200
33
30
4x109
77
12.8
7-9
200-220
--
1530
---
90-100
13.0
81
88
System/
Process
Feedstock
NIST Process
I
SemiMolasses
industrial
4,00025,000L
NIST Process
II
Molasses
Single stage
NIST Process
II
Molasses
Two-stage
Source: DENR (1989)
Organism
Residence
Time (h)
Sugar
Concentration
Initial
Final
(g/l)
(g/l)
Yeast
Concentration
(g/l)
(cells/ml)
Ethanol
Concn.
(g/l)
Volumetric
Productivity
(g/l-h)
-ditto-
12-16
150
--
2030
---
65-100
4-6
Mutant of F9-5
1.39
141.3
--
97
---
57
41.2
-ditto-
1.85
141.3
--
97
---
59
31.9
82
89
APPENDIX D
Simplified Process Flow Diagram of Alcohol Production from Sugarcane and Starches
CARBOHYDRATES EXTRACTION
AND MASH PREPARATION
SUGAR
CANE
JUICE
EXTRACTIO
N
SUGAR
JUICE
MASH PRE-
BAGASSE
ENZYMES
FERMENTATION
STRIPPING AND DISTILLATION
ABSOLUT
E
ETHANO
YEAST
FERMENTATION
STRIPPING
DISTILLATIO
N
HYDROU
S
ETHANO
SACCHARIF
ICATION
STILLAGE
FUSEL
OIL
LIQUEFACTION
STARCH
ES
PASTE
PREPARATI
ON
PRELIQUEFACTION
ENZYMES
Source : Armas and Cryde (1984)
83
90
84
APPENDIX E
Motor Vehicle Information on Compatibility with Bioethanol
Holden
All gasoline (petrol) engine vehicles since 1986 will
operate satisfactorily on E10 except as listed below.
The following models which do not operate
satisfactorily
on
E10
fuel:
Apollo (1/87-7/89), Nova (2/89-7/94), Barina (19851994), Drover (1985-1987), Scurry (1985-1986),
Astra (1984-1989).
Ford
All petrol engine vehicles since 1986 will operate
satisfactorily on E10 except as listed below.
The following models may not operate satisfactorily
on E10 fuel because of drivability concerns:
Focus (All), F-series (1986-1992), Ka (All), Maverick
(1988-1993), Mondeo (All), Transit (1996 onwards).
The following models do not operate satisfactorily on
E10
fuel:
Capri (1989-1994), Courier (All), Econovan (pre2002), Festiva (1991-1999), Laser 1.3L & 1.5L (19801989), Laser 1.6L (1989-2002), Raider (All), Telstar
(All).
Mitsubishi
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Mitsubishi vehicles with carburettor fuel systems built
before 1991 may experience hot fuel handling
concerns and may experience a lower level of
durability in some fuel system components.
Toyota
All Toyota models manufactured locally or imported
by Toyota Australia since 1987 will operate
satisfactorily on E10 fuel except as listed below.
The following models will not operate satisfactorily
on E10 fuel due to material compatibility issues:
Camry with carburettor engines pre July 1989 and
Corolla pre July 1994.
Supra - pre May 1993, Cressida - pre Feb 1993,
Paseo - pre Aug 1995, Starlet - pre July 1999.
Land Cruiser - pre Aug 1992, Coaster - pre Jan 1993,
85
Dyna - pre May 1995, Tarago - pre Oct 1996, Hilux ,
Hiace, & 4 Runner - pre Aug 1997, Townace - pre
Dec 1998.
Alfa Romeo
All Alfa Romeo vehicles imported since 1998 must
run on minimum 95 RON fuel (premium unleaded
petrol).
Post 1998 Alfa Romeo vehicles will operate
satisfactorily on E5 ethanol blended petrol (European
Standard EN 228). E10 ethanol blended petrol is not
recommended as there are material compatibility and
drivability issues. E10 may be used in emergency
situations.
E10 ethanol blended petrol is not recommended for
earlier model Alfa Romeo vehicles due to material
compatibility issues.
Audi
All current Audi vehicles must run on minimum 95
RON fuel (premium unleaded petrol). All Audi
vehicle models since 1986 will operate satisfactorily
on E10 except as listed below:
Audi A3 1.8L (Engine Code 'APG' 2000 onwards)
and A4 2.0L (Engine Code 'ALT' 2001 onwards) will
operate satisfactorily on E5 ethanol blended petrol
(European
Standard
EN
228).
However,
E10Â ethanol blended petrol is not recommended for
these vehicle models as there are material
compatibility and drivability issues. E10 may be used
in emergency situations.
Bentley
All petrol engine vehicles since 1990 will operate
satisfactorily on E10.
BMW
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Citroen
All Citroen vehicles are required to run on minimum
95 RON fuel (premium unleaded petrol).
Citroen vehicles will operate satisfactorily on E5
blended petrol (European Standard EN 228).
However, E10 blended petrol is not recommended
because of drivability and/or material compatibility
issues. E10 may be used in emergency situations.
86
Chrysler
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Daewoo
GMDaewoo does not recommend the use of ethanol
blended petrol.
Daihatsu
Use of E10 in any Daihatsu model vehicles is not
recommended because of material incompatibility.
Honda
All Honda vehicles should use the fuel recommended
in the Owner's Manual.
The following models will operate satisfactorily on
E10:
Insight - 2004 onwards; Civic range (including Civic
Hybrid) - 2004 onwards; S2000 - 2004 onwards;
CRV - 2003 onwards; MD-X - 2003 onwards;
Accord & Accord Euro - 2003 onwards.
Honda does not recommend E10 for other vehicle
models because there may be drivability issues.
Hyundai
Hyundai vehicles will operate satisfactorily on E10,
but if engine drivability concerns occur revert back
to 100% unleaded petrol.
Ferrari
Ferrari does not recommend the use of ethanol blend
petrol. E10 may be used in emergency situations.
Jaguar
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Kia
All petrol engined vehicles since 1996 will operate
satisfactorily on E10 but if engine driveability
concerns occur revert back to 100% unleaded petrol.
Please refer to Owner' s Manual for further details.
Land Rover
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Lexus
All models will operate satisfactorily on E10 except
for
the
model
listed
below:
The following model will not operate satisfactorily
on
E10
fuel:
IS200 - pre May 2002.
Maserati
Maserati does not recommend the use of ethanol
87
blend petrol. E10 may be used in emergency
situations.
Mazda
Mazda 323 1.8L (1994 onwards), Mazda 323 2.0L
(2001 onwards), Mazda2 (11/02 onwards), Mazda3
(All), Premacy (5/02 onwards), Mazda6 (8/02
onwards), 800M and Millenia (8/98 onwards), RX-8
(7/03 onwards), MPV (8/99 onwards), Tribute (All)
and E-series (2002 fuel injected models onwards)
vehicles will operate satisfactorily on E10.
All other models not listed above do not operate
satisfactorily on E10.
Mercedes-Benz
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
MG
MGF (2000 onwards), MG ZT (2002 onward) and
MG TF (2002 onward) vehicles may operate
satisfactorily on E10. However, use of E10 may
affect engine calibration and emissions.
MGF (pre-2000) does not operate satisfactorily on
E10.
Nissan
Nissan vehicles manufactured from 1 January 2004
onwards are capable of operation on ethanolblended fuels up to E10 (10% ethanol),
providing that blending of the ethanol component
to the petroleum component of the fuel has been
properly made at the fuel refinery (ie there is no
"splash-blending"
of
the
fuel).
Â
For Nissan vehicles manufactured prior to 1 January
2004, Nissan Australia does not recommend the use
of E10 because of drivability concerns and/or
material compatibility issues.
Peugeot
All Peugeot vehicles are required to run on minimum
95 RON fuel (premium unleaded petrol).
Peugeot vehicles will operate satisfactorily on E5
blended petrol (European Standard EN 228).
However, E10 blended petrol is not recommended
because of drivability and/or material compatibility
issues. E10 may be used in emergency situations.
88
Proton
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Rover
Rover 75 (2001 onwards) vehicles may operate
satisfactorily on E10. However, use of E10 may
affect engine calibration and emissions.
Renault
All petrol engine vehicles since 2001 will operate
satisfactorily on E10 but Renault does not
recommend its use
Rolls Royce
All petrol engine vehicles since 1990 until 2002 will
operate satisfactorily on E10.
Saab
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Subaru
Subaru Liberty B4 (all year models) and Impreza
WRX STI (1999 and 2000) do not operate
satisfactorily on E10.
All other since MY1990 petrol engine Subaru
vehicles will operate satisfactorily on E10.
Suzuki
Suzuki Alto, Mighty Boy, Wagon R+, Swift/Cino,
Ignis Sport (1.5 litre requires 98RON), Sierra,
Stockman, Vitara, X-90, Jimny (SOHC) and Super
Carry vehicles do not operate satisfactorily on E10.
Suzuki Baleno and Baleno GTX will operate
satisfactorily on E10 but Suzuki does not
recommend its use in these vehicles.
Ignis (1.3 litre), Liana, Grand Vitara/XL-7, Jimny
(DOHC) and Carry (1.3 litre) vehicles will operate
satisfactorily on E10.
Volkswagen
All Volkswagen vehicles will operate satisfactorily
on E10, but Volkswagen does not recommend it.
Volvo
All petrol engine vehicles since 1986 will operate
satisfactorily on E10.
Source: The Australian Federation of Automotive Industries