Methanol Production from Synthesis Gas derived from Municipal Solid Waste Department of Chemical Engineering University of Illinois at Chicago ChE. 397 Group Charlie: Priya Chetty, Scott Morgan, Brian Mottel, Daniyal Qamar, Sukhjinder Singh Mentor: Dennis O’Brien Instructor: Dr. Jeffery Perl 3/3/11 Group Charlie Page 1 Table of Contents I. II. III. IV. V. VI. VII. VIII. IX. Abstract Executive Summary Introduction Process Description Process Control Environmental Concerns and their mitigation Economics Recommendations Appendices 1. Design Basis 2. Block Flow Diagram 3. Process Flow Diagram 4. Material and Energy balances 5. Calculations 6. Process Simulation in ASPEN 7. Annotated Equipment List 8. Economic Evaluation 9. Utilities 10. Conceptual Control Scheme 11. General Arrangement 12. Distribution and End-use Issues review 13. Constraints Review 1. Feedstock definition 2. Conversion technology description 3. Separation technology description 4. Product description 5. Location sensitivity Analysis 6. ESH law compliance 7. Laws of physics compliance 8. Turndown ratio 14. Applicable Standards 15. Project Communications File 16. Information Sources and References Group Charlie Page 2 I. Abstract Methanol is a chemical which is used in many diverse applications. Methanol is commonly used as a fuel, as antifreeze, and as a solvent, but can also be utilized to produce plastics, adhesives, and dyes. The most common method for producing methanol involves combining methane (natural gas) and water to produce synthesis gas, which is carbon monoxide and diatomic hydrogen. This synthesis gas is then used to produce methanol. The issue with this process is that methane is very useful as a heating fuel which is why it is used to fulfill residential heating needs. This method of methanol production is essentially using a fuel to produce another fuel as the product. Our goal is to make Methanol by using a sustainable source of fuel. The source of our synthesis gas is Chicago Land Municipal Solid Waste. We are utilizing a waste stream rather than a fossil sourced feed stock. This will be the source of our synthesis gas. We will then compress the synthesis gas, and feed it into a multiple feed reactor which contains Cu/ZnO/Al2O3 catalysts to produce methanol. Unused synthesis gas will be separated from the initial product stream and recycled back into the reactor. The initial product stream will contain methanol, along with water, as well as other alcohols such as ethanol, and propanol. To ensure that the methanol produced will meet the grade AA industry standard, which states that it must be 99.85% pure, the initial product will go through a flash separator followed by two distillation columns. Group Charlie Page 3 II. Executive Summary By utilizing the process outlined in this report, 99.85% pure methanol can be produced at a rate of 1060 tons per day from a feed stock of 1700 tons per day of synthesis gas which will be produced by gasification of 5,000 tons per day of municipal solid waste. Conversion of synthesis gas to methanol is conducted in a Lurgi reactor which will utilize a Cu/ZnO/Al2O3 catalyst, and a recycle stream. The desired product will then be separated from byproducts via flash separation, and purified using two distillation columns. The capital cost needed to build a plant of this magnitude is $116.8 million. The internal rate of return for this plant would be 25.60%, and the payback period would be 5 years. III. Introduction The objective of the syngas to methanol process is to produce 1060 tons/day of grade AA methanol for use in the chemical, automotive, and plastics industries. The syngas that is procured for this process will have been produced by gasification of municipal sold waste. There are many advantages to utilizing syngas produced via this method, such as; it eliminates the need for methane, it is less expensive due to the solid waste tipping fee, and it is a much more green technology which is important to consumers. Currently there are 90 methanol plants worldwide with an annual production of 11 billion gallons, generating $12 billion per year in revenue. The market outlook for the future of the methanol industry is good, with global demand expected to rise in the years to come. Group Charlie Page 4 The gasification plant will be located in the Chicagoland area because ample municipal solid waste is produced there; in fact the average production is 25,000 tons per day. The methanol plant will be located near the gasification plant, because geographic proximity will reduce transportation costs, which also reduces the consumer price of the product. Group Charlie Page 5 IV. Process Description The overall process starts as syngas from group Delta enters the very first heat exchanger. The syngas, now cool enough to enter a compressor, goes through a two stage compressor with cooling between stages. The syngas at a high enough pressure to react under catalytic conditions now enters a reactor. A catalyst based on Cu/Zn/Al oxides is used and it gives a conversion of Carbon Monoxide to methanol of 0.5 per pass (based on reaction 1 below). As reactions 1 through 4 (listed below) take place in the reactor all the products are discharged towards a heat exchanger. Methanol synthesis involves highly exothermic reactions and the heat accumulates in the product stream. This heat must be taken out so it can be utilized in reboilers for distillation columns. The product stream is also highly pressurized thus it goes through a turbo expander so we can run it through a turbine and make power to use in air coolers and put into the grid. After the turbo expander the products go through heat exchangers and finally into a flash drum. The flash drum operates at conditions where the non condensables are separated easily and sent back to the compressor in the beginning of the process as a recycle stream. This recycle stream contains a high concentration of CO2 that accumulates as the process goes on. A purge from this recycle stream works to minimize the accumulation of this CO2. The condensables, ethanol, butanol, methanol, and water proceed to the separations train where they go through a couple distillation columns. The first column gets rid of any left over non condensables, CO, CO2, H2 and the second one gives AA grade methanol separated from ethanol, butanol, and water. Group Charlie Page 6 Detailed descriptions of units are given below: Compressor The syngas from the gasifier will reach the methanol synthesis plant at 300 psi. But this pressure is too low for the reactor and needs to be raised. There will be a multistage compressor to raise the pressure to the needed value of 1200 psi. Since it is a multistage compressor there is some pressure drop between each of the stages, due to the fact that when the gas is heated in the compressor it will need to be cooled, and this cooling will decrease the pressure. So instead of having an overall compression ratio of 2:1, the total compression will need to be around 2.5:1 to overcome the pressure drop from the inter-stage coolers. The cooling water in this part of the process will be at 90 °C, because this will eliminate the need for a cooling tower which is fairly expensive to install. Reactor Methanol synthesis is a very complex process since it is very equilibrium limited, and quite exothermic; therefore it is imperative that the correct type of reactor is chosen to obtain the desired results. There are many diverse types of reactors which may be used in the synthesis of methanol, which utilize various methods of catalysis, and removal of heat from the reaction. A significant amount of time was spent evaluating the different types of reactors to ensure that the correct one was chosen. Below is an example of some of the reactors that were considered along with information about each: Group Charlie Page 7 ICI Multiple Feed Quench Reactor The ICI reactor uses multiple feeds to bring the reaction temperature down to the desired value. This however requires a very high flow of air into the reactor which reduces the effectiveness of the compressor. The reactor utilizes multiple catalyst beds to reach a conversion of 35-40%. The maximum production rate of the ICI multiple feed quench reactor is 5000 tons per day. The amount of syngas required to remove the heat of the reaction is in excess of that which is able to be procured, therefore this reactor did not meet the necessary requirements for this process. Lurgi Combination Converter Reactor The Lurgi reactor works as an ICI reactor but it also combines water cooling to control the reaction temperature. The reactor works as a heat exchanger with tube and shell sides. The reactions take place in the shell side while coolants go through the tube side. There are essentially two reactor vessels the first one has two feeds to it. The first feed (cooling stream) is the cold fresh syngas; the second feed (reactant stream) is the hotter product gas from the second reactor vessel. This hot product stream has leftover CO and H2 that can react again and it does so in the first vessel. This essentially gives two reactors in series and therefore a higher conversion. The cold fresh syngas is used to control the temperature of the first reactor and this colder gas proceeds to the second reactor as the reactant stream. To control the temperature of the second reactor, steam is used. Water at its saturation point (428 F and 420.61 psi) is kept in a steam drum and as this water goes through the reactor it removes energy from the product stream in the reactor and evaporates, the steam is sent back to the drum where new cooling water controls the saturation point. This loop continues until the process reaches steady state, and before that a light up heater is used to bring the reactant temperature up to the desired value. Group Charlie Page 8 Example of Lurgi Methanol Reactor courtesy of http://www.lurgi.com/ In the production of methanol from syngas, which will have a H2 to CO ratio of 2:1, there are several reactions that will have to be considered: CO + 2H2 ↔ CH3OH (1) CO2 + H2 ↔ CO + H2O (2) CO2 + 3H2 ↔ CH3OH + H2O (3) 2CO + 4H2 ↔ C2H5OH + H2O (4) These reactions occur simultaneously inside of the reactor, during the methanol synthesis step. Group Charlie Page 9 The kinetics of the above reactions can be found in literature. From all of the reaction kinetics, it is possible to find the production yield of each of the components in the syngas. The following reactions are for the kinetics of methanol synthesis: 3OH , A3 rCH rH 2O , B 2 k ps , A3 K CO [ f CO f 3/ 2 H 2 fCH 3OH /( f 1/ 2 H 2 K o p1 )] (1 K CO f CO K CO2 f CO2 )[ f 1/ 2 H 2 ( K H 2O / K 1/ 2 H 2 ) f H 2O ] k ps , B 2 K CO2 ( fCO2 f H 2 f H 2O f CO / K o p 2 ) (1 K CO fCO K CO2 fCO2 )[ f 1/ 2 H 2 ( K H 2O / K 1/ 2 H 2 ) f H 2O ] 3OH ,C 3 rCH k ps ,C 3 K CO2 [ fCO2 f 3/ 2 H 2 fCH3OH f H 2O /( f 3/ 2 H 2 K o p 3 )] (1 K CO fCO K CO2 f CO2 )[ f 1/ 2 H 2 ( K H 2O / K 1/ 2 H 2 ) f H 2O ] Catalyst In the reactor there will be a Cu/Zn/Al catalyst to drive the overall reaction towards methanol. This catalyst is used in many other reactors. The poisons of this specific catalyst are sulfur, chlorine, CO2, and high temperatures. The amount of CO2 activates the catalyst and it also deactivates it, so an adequate amount of CO2 must be allowed into the reactor. So in order to ensure that the catalyst life can stay at a reasonable time, the syngas that is fed into the reactor must have none of the above chemicals, and the temperature of the reactor will need to stay at 518 F. The conversions are 50% for reaction 1, 13% for reaction 2, 2 % for reaction 3, and 2% for reaction 4. After the syngas has been reacted it will be at 1185 psi and 518 F. The reacted gas will then go through several pieces of equipment until it reaches the distillation columns for purification of the product. The gas will need to be split for a recycle feed and remaining gas. Group Charlie Page 10 The remaining gas will have a high amount of crude methanol and fewer impurities than before. After this the stream will be put through a condenser and heat exchanger in order to have the methanol in the liquid phase and to be at a much lower temperature. Then the crude methanol is put through a flash tank and finally to the distillation unit. Heat Exchangers Since many of the different pieces of equipment throughout the process need the syngas or methanol at different temperatures, there will be three heat exchangers throughout the entire process. These particular heat exchangers will be a shell and tube heat exchangers, which consists of a series of tubes. One set of these tubes contains the fluid that must be either heated or cooled. The second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required. The fluid used in this case will be water. A heat exchanger will be present before and after the multi-stage compressor in order to utilize the energy from a high compression process. The third heat exchanger will be present after the reactor. The reactor will be producing heat at an amount of -12,891,1520 Btu/hr, which can be utilized with this heat exchanger. The first heat exchanger will have an area of 64.18 ft2, with 6 inner tubes having an inner and outer diameter of 0.33ft and 0.34ft respectively. The second heat exchanger will have an area of 1200 ft2, with 105 inner tubes having an inner and outer diameter of 0.11ft and .12ft respectively. The third heat exchanger will have an area of 425 ft2, with 15 inner tubes having an inner and outer diameter of 0.33ft and .34ft respectively. The energy balances around the heat exchangers can be found in the appendix, and they show how much energy is needed to run each of them. Group Charlie Page 11 There will be several non condensables in the product stream coming from the reactor. Since these gasses do not dissolve very readily in the crude product they are very easy to separate. A flash drum is used to do so. Flash Drum A flash drum with a diameter of 4.63 ft and a height of 7.79 ft is being used for a simple separation of CO, H2, and CO2 from methanol, water, n-butane, and ethanol. The drum operates at a temperature of 118 °F and a pressure of 638 psi (Grue et. al.). The energy lost in the flash drum is minimized by using a heat exchanger before and lowering the product temperature to 118 °F, this heat is then used in the distillation columns. High separation percentages of non condensables were achieved using this flash drum. 97.5% of CO, 76.44% of CO2, 3.9% methanol, 99.99% of H2, and 2.3% of Ethanol are the percentages of feed components to the flash drum that are sent to the vapor stream, the rest was sent into the liquid stream which is distilled twice to obtain grade AA methanol. It can be noted that the lesser CO2 than CO goes into the vapor stream and this can be attributed to the fact that CO2 readily dissolves in the H20 and methanol rich stream that goes off as liquid to the distillation column. Distillation Columns In order to obtain the grade AA methanol at the end of the process, there will need to be two distillation columns installed. Both of the columns will need both condensers and reboilers on them. After the second distillation column the methanol will be pure enough to sell as Grade AA Methanol. The first distillation column will need to be at 31psi, 118°F, have 15 trays, and the feed will be located above the 5th tray. The second distillation column will need to be at 31psi, 120°F, have 33 trays, and the feed will need to be at the 13th tray to obtain to correct Group Charlie Page 12 purity of methanol. After the first distillation process there will be water, ethanol, and other higher hydrocarbons, along with the methanol. Majority of the methanol will be in the bottom stream, including water and ethanol, which will then be fed to the second distillation column. After the second distillation column, methanol will be present the distillate stream and the water along with methanol and ethanol will be in the bottom stream. The water will be used for either cooling another part of the process, or it could be heated to produce steam to be used in a heat exchanger or to power some of the necessary equipment. The ethanol and higher hydrocarbons will need to be separated from methanol and then they can be sold to a different company to be used for a different process. Using ASPEN it is possible to find the dew and bubble points of the streams exiting the columns. From all of the information, the height of the columns can be found and from that the sizing. Group Charlie Page 13 V. Process Control A control process is very important in the aspect of manufacturing a quality product. This can be assured by having the quality designed into the product and also into the manufacturing process. Achieving this will allow the use of the process control to ensure that the methanol produced meets the standards of grade AA methanol. At this point, the design basis is not set to ensure a complete process control. However, there are a few vendors that provide process control solutions. Methanol@Max provided process controls specifically for methanol production plants. They use particular software, which connects to the DCS and controls. This helps to optimize the plant minute by minute, every hour of the day, every day of the year. The software does use the PLC method. The program will reduce the variance in the parameters and reduce the need for operator intervention. This will also help in improved separation, reduce energy consumption, and improve the overall plant stability. Maximizing conversion and increasing methanol production will be the key components of this software. Also, maintaining the reactor’s parameters and adjusting them accordingly to the software will help ensure productivity. Group Charlie Page 14 VI. Environmental Concerns and their mitigation Methanol is highly flammable and may result in fire and explosive hazards, therefore fireproof walls must be incorporated in the plant design to ensure personnel safety. Furthermore, respirators and gloves must be utilized while working in areas of high vapor methanol concentrations since prolonged human exposure to methanol has resulted in headaches, dizziness, nausea, gastric upsets, blurred vision, and blindness. Humans should not be exposed to methanol concentrations greater than 198ppm based on OSHA regulations. Overall, methanol does not pose a high hazard to health; however, effective procedures must be implemented to ensure the health and safety of the personnel. Methanol synthesis generates CO2 resulting in greenhouse gases emissions into the atmosphere and over long term global warming. In addition, CO2 is heavier than air, therefore, increasing its tendency to leak through open valves; therefore, stringent guideless must be executed while operating valves. To ensure environmental concerns, the plant will abide to EPA and all other environmental regulation agencies and never discharge material that is detrimental to the environment without utilizing proper guidelines. The plant will abide by the waste water stream regulation proposed by the municipal waste water treatment agency. Most heavy metals in the slag or fly ash flue can be either used in asphalt construction or converted to fine, gritty material similar to sand respectively. Remaining heavy metals which may have run into the waste water can be removed through flocculation and precipitation and discarded as chemical waste. Further research will be conducted to ensure the processes discussed have competing edge, and all technological advances to impede harmful environmental impact will be embedded in the plant design. Group Charlie Page 15 VII. Economics VIII. Recommendations With all industrial processes there will be many recommendations to ensure that the process would work both efficiently and economically. Some things that could change throughout our process would be reactor conditions, catalyst for the reactor and CO2 removal, and conditions for any other piece of equipment. Changing conditions for any piece of equipment would help to decrease the price of the process, but on the other hand it could cause inefficiency in the system. A cost evaluation would have to be preformed not only on the entire system but each piece of equipment to ensure that the process can make the most profit. Any piece of equipment that needs high pressure or temperature will increase the cost of that equipment. If the process was able to make the same amount of final product with lower pressure or temperature, this would decrease the price of installment and increase the final profit. Catalysts are used in almost all chemical productions nowadays and choosing the best catalyst for the process is extremely important. We are using a Cu/Zn/Al catalyst for the methanol synthesis from syngas, and it seems to be the same one that is used in industrial processes for methanol synthesis. Since catalysts are extremely expensive the choice of the correct one is vital. If there were to be a cheaper or one that produced higher yields, they would need to be considered in our process. There is a lot of research in the field of catalysis, and ones of the future seem that they will be able to make processes run at lower conditions, which will in turn create lower prices on equipment. Group Charlie Page 16 The most expensive part of our process, along with industrial processes, is the reactor to produce crude methanol. This is due to the fact that very high pressure is needed to ensure the crude methanol is produced with the fewest impurities. Our reactor is running at 420 psi and 491°F. If it were possible to lower both pressure and temperature in the reactor, this would decrease the overall price of the process. The Lurgi reactor seems to be the best reactor for the methanol synthesis reaction, because it does not require an excess amount of syngas to cool it like the ICI Synetix reactor. There could be other reactors better suited for the process, but it seems that the Lurgi will be the most cost effective and efficient. IX Appendices 1. Design Basis By utilizing the process outlined in this report, 99.85% pure methanol can be produced at a rate of 1059 tons per day from a feed stock of 1700 tons per day synthesis gas which will be produced by gasifying 25,000 tons per day of municipal solid waste. Conversion of synthesis gas to methanol is conducted in a LURGI quench reactor which will utilize a Cu/ZnO/Al2O3 catalyst, and a recycle stream. The desired product is then separated from byproducts via flash separation followed by two distillation columns. Ideally the plant would be located in the Chicagoland area, because this is where the synthesis gas feedstock will be produced, and geographic proximity will reduce transportation costs. The capital cost needed to build a plant of this magnitude is $116.8 million. The internal rate of return for this plant would be 25.60%, and the payback period would be 5 years. Group Charlie Page 17 . A thermal oxidizer will be used to destroy hazardous air pollutants and volatile organic compounds. They will be destroyed via thermal combustion and eventually changed to form CO2 and water. CO2 will also be released from distillation column 1 in the distillate stream at an amount of 23,180.57 lb/hr. This CO2 will be released into the atmosphere. The methanol produced at this particular power plant will have a purity of 99.85%, which will qualify it to be sold as grade AA methanol. There are several requirements that need to be met in order for it to be called grade AA methanol. The amounts of acetone and aldehyde can only be at max 30 wt-ppm. Acetone and ethanol can only be present at a max limit of of 10 wt-ppm and there also cannot be any higher alcohols present. Finally, water must be only present at maximum limit of 1,000 wt.-ppm. 2. Block Flow Diagram 3. Process Flow Diagram The following figure shows the overall process flow diagram. Smaller pieces of the picture are shown below for more detail Group Charlie Page 18 This figure shows the first heat exchanger, compressor, and the second heat exchanger. Group Charlie Page 19 This figure shows the stream coming into the reactor, the steam drum for the reactor, the turbo expander, and finally a heat exchanger that cools the product down. Group Charlie Page 20 This figure shows an air cooler, a heat exchanger, and then the flash drum. The stream leaving the flash drum on the top is the recycle stream that loops back to join fresh syngas into the compressor. Group Charlie Page 21 This shows the final step of the process where crude methanol is put through distillation columns and grade AA methanol is produced(P-64) Group Charlie Page 22 4. Material and Energy balances: 5. Calculations: Flash Drum: Calculations were made to determine the amount of vapor going into the vapor stream of the flash drum: Component n CO CO2 METHA-01 N-BUT-01 ACETO-01 H2O HYDRO-01 DIMET-01 ETHANOL Total Flow in (lbmol/hr) Flash Drum Concentrations In Vapor Liquid (lbmol/hr) (lbmol/hr) (lbmol/hr) 3223.377 3141.149 82.22929 2235.352 1708.629 526.7114 3184.629 125.1214 3059.511 7.702618 0.03732 7.6653 0 0 0 305.458 3.630568 301.8272 5746.344 5746.338 0.000514 0 0 0 31.36592 0.740183 30.62576 % in vapor 97.449 76.43666 3.928915 0.484515 1.188566 99.99991 2.359832 14734.23 To calculate percentage the following formula was used: %n Vaporn Feed n Where: %n is the percentage of component n Vaporn is the lbmol/hr of component n in the vapor stream Group Charlie Page 23 Feedn is the lbmol/hr of component n in the feed stream The flash drum was also sized: Vapor In Liquid In Vapor Out Liquid In Max Vapor ft3/s (outlet) Density of vapor lb/ft3 Density of Liquid lb/ft3 k value @ 300 psi max velocity ft/s area of drum ft3 Radius of drum ft Diamter ft Length Total Volume Flash Drum Sizing Fractions Total flows ft3/hr 0.781183 190665.198 0.218817 190665.198 1 187124.047 1 3540.05861 51.9789 1.734489 49.19985 0.33 1.726301 30.10998 3.095853 6.191706 3.84889 115.89 radius good ft Area good Length good Flows ft3/hr 148944.455 11.589 187124.047 3540.05861 20 1256.637 0.092222 To get the max vapor velocity the Sauders Brown equation was used: Vmax l v K v Where: Vmax is the maximum vapor velocity allowed in ft/s K is a constant known for Flash drums at several different pressures ρl is the liquid density lb/ft3 Group Charlie Page 24 ρv is the vapor densiy lb/ft3 Once the vapor velocity was found, it was used to find the total area of the flash drum required: A V Vmax Where: A is the area of the flash drum in ft2 V is the highest vapor velocity the flash drum needs to handle according to the design in ft3/s V is the max vapor velocity as calculated above The diameter of the drum can be found very easily using the simple area of a circle formula A=ΠR2 The height of the drum depends on the amount of liquid that is present in the flash drum for a given amount of time. The following formula was used to determine the height of the drum: 2 T W H A Where: A factor of two is used because it is assumed the tank is halfway full of liquid Group Charlie Page 25 H is the height of the drum T is the time in s that the liquid stays in the drum (5 minutes was used for liquid inventory) W is the liquid flow rate in ft3/min that flows out Heat Exchangers: Calculations were made to find heat exchanger sizes: HX 1 sizing 90/10 CU/NI .049 400 psig 600°F Area of heat exchanger ft2 Heat exchanged Btu/hr OD ft ID ft wall thickness Length ft Area of single tube ft2 Overall Heat Transfer Coefficient Btu/F ft2 hr LMTD F Area requirement calculation Number of Tubes 64.175 3396590 0.3415 0.333333 0.004083 10 10.72854 149.6937 353.5688 64.175 5.981709 HX 2 Sizing Area of heat exchanger ft2 Heat exchanged Btu/hr OD ft ID ft wall thickness Length ft Area of single tube ft2 Overall Heat Transfer Coefficient Btu/F ft2 hr LMTD F Area requirement calculation Number of Tubes 1200 43795974 0.124672 0.111549 0.006562 20 7.833368 149.6937 356.5221 820.6243 104.7601 HX 3 Sizing Group Charlie Page 26 Max Pressure psi Area of heat exchanger ft2 Heat exchanged Btu/hr OD ft ID ft wall thickness Length ft Area of single tube ft2 Overall Heat Transfer Coefficient Btu/F ft2 hr LMTD F Area requirement calculation Number of Tubes 1200 425.3894 10752639 0.3415 0.333333 0.004083 15 16.09281 149.6937 303.4667 236.7013 14.70852 The amount of heat exchanged was calculated using ASPEN and the heat exchange area was based on the equations below: Calculate Q (this gives the same results as ASPEN does): Q m C T Calculate Area of heat exchanger: Q U A Tlm Where: Q is the heat exchanged in Btu/hr U is the overall heat transfer coefficient, assume: U = 100 (BTU/F*ft^2*h) Delta Tlm is the log mean temperature difference in F To Calculate log mean temp (countercurrent flow): Group Charlie Page 27 Where: T1 inlet shell fluid temp T 2 outlet shell fluid temp t 1 inlet tube side temp t 2 outlet tube-side temp Calculate tubes required using pipe parameters from Towler. Based on the number of tubes, utilize Seider Table and obtain the closest number of tubes with corresponding shell diameter Equipment Cost procedure: Cost of Pumps Cost of centrifugal pump is based on volumetric flowrate and head required 1.) Utilize cost equation Group Charlie Page 28 Pc is the power consumption S is the sizing factor for the pump 2.) Utilize sizing and power consumption equation respectively to plug into cost equation Pc (power consumption) in HP Q (flowrate) in Gal/min H (pump head) in Ft (density) in lbs/gal np = -0.316 + 0.24051* (lnQ)-0.01199*(lnQ)^2 (fractional efficiency of the pump) in dimensionless units nm = 0.80 + 0.0319 * (lnPc)-0.00182 * (lnPc)^2 (fractional efficiency of the motor) in dimensionless units 3.) Applying Seider’s value, calculate purchasing cost utilizing the equations Group Charlie Page 29 Pump: Cp = Ft * Fm * Cb Motor: Cp = Ft * Cb Ft (type factor) 2.7 Fm (material factor) 1.0 Cost of Compressors I.) Purchase cost values obtained from Garrett and Walas (1988) for electric motor drive, cast iron or carbon-steel construction since Cp= Cb II.) For other drives and materials of construction Cp = Fd * Fm * Cb Drive Steam turbine Group Charlie Fd Material Fm 1.15 Stainless steel 2.5 Page 30 Gas turbine 1.25 Nickel Alloy 5 Cost of Methanol Synthesis Reactor Utilize shell and tube exchanger approach Fixed head A is area for heat exchanger in square ft. Cb = exp (11.0515-0.9228(ln(A))+0.09861(ln(A))^2) Fm = a+((A/100)^b) Fp = 0.9803 + 0.018*(P/100)+0.0017*(P/100)^2 FI values can be obtained in Seider and Seader Cp= Fp*Fm*FI*Cb Group Charlie Page 31 Base and Purchasing cost of the MSR Type Fixed P a b A Psig sqft 1000? 418,879? Fm 1 FI 1 Fp 1.33 Cb Cp $ $ 5,302,257? 7,053,593? * data need to be verified through aspen simulation and operating parameters keep changing. Cost of Distillation Columns *need operating conditions and dimensions Towers for 9,000 < W < 2,500,000 lb (?) Cv = exp (7.0374+0.18255(ln(W))+0.02297(ln(W))^2 Group Charlie Page 32 Towers for 3 < Di < 24ft and 27< L<170 ft Cpl = 237.1 * (Di)0.63316*(L)^0.80161 Weight calculation: W = pi()*(Di+ts)*(L+0.8Di)*ts*rho For Po min = 10 psig Po > 1000psig use Po= 1.1* Po and neglect equation below Pd = exp (6.60608+0.91615(ln(Po))+0.0015655(ln(Po))^2) tp= (Pd*Di)/(2S*E-1.2*Pd) tp must be greater than a minimum value for rigidity based on the diameter S is the maximum allowable stress of the shell material, at the designed temp in lbs per square inch E is the fractional weld efficiency 6. Process Simulation in ASPEN: An Overall process in ASPEN is shown below; each section is then broken down for simplicity Group Charlie Page 33 Compression: Group Charlie Page 34 Reactor: Separations Train: Group Charlie Page 35 Simulation Detail: The process was simulated in ASPEN and the results were used for sizing calculations and reactor details. The mapping of the following units is discussed below: 1) Reactor 2) Compressor 3) Heat exchangers 4) Turbo expander 5) Flash drum Group Charlie Page 36 6) Distillation columns 1. REACTOR: The process was started with a simple RSTOIC reactor: The inlet flow was defined to be 1700 tpd, temperature of 518 F and a pressure of 1190 psi. A pressure drop of 10 psi was taken through the reactor. Group Charlie Page 37 The temperature and pressure were defined as in the screen above. These values were obtained from literature. Furthermore four reactions were defined as below, with conversions taken from literature: Group Charlie Page 38 The new button is hit to add new reactions and this is where the reactants, products, and the conversions are defined: 2. Compressor: After adding the reactor, a compressor was added but since the feed syngas was too hot to be fed to a compressor it was cooled using a heat exchanger. To map the compressor in ASPEN the following window was used: Group Charlie Page 39 Only vapor phase (selected in the convergence tab) was used through this condenser since only syngas and some recycled components well above their boiling points will be going through the compressor. The discharge pressure was the only number required for this unit and it was set at 1200 psi. 3. Heat Exchangers: Several heat exchangers were used through the whole simulation. There was one before the compression train, another one cooling down the compressed syngas. Two more heat exchangers were used to cool down the products from the reactor, and finally another one was used to simulate air coolers. The hot stream outlet temperature and the pressure drop through the tubes were the only specifications made for the heat exchanger block. The pressure drop was defined as 5 psi for all the heat exchangers (Gulley). Cooling water stream temperature and flow rates going into heat exchangers were Group Charlie Page 40 also defined. The amount of heat exchangers and cooling water used were determined by the optimization of heat exchanger size. For example using a single heat exchanger with very small temperature approaches resulted in immense heat exchange areas .The following pictures show how they were modeled: Temperature exchange: Pressure drop: Group Charlie Page 41 All the heat exchangers were designed in a similar manner. After the reactor the product stream goes through a turbo expander. 4. Turbo Expander: In the pressure changers tab in ASPEN the compressor can be selected to act as a turbine as well. The following screen shot describes that procedure: The stream coming from the reactor is fed into the turbo expander and the discharge pressure is defined. This discharge pressure is the same as the pressure required for the flash drum plus the pressure drop for the two heat exchangers. A technicality that arises in the turbo expander design is the fact the turbines can only be fed gases. So any liquid would cause a problem and ASPEN will show errors. So it was made sure that there were no heat exchangers installed before the expander and all the product was in gas phase. After the turbo expander the product stream goes into a flash drum. Group Charlie Page 42 5. Flash Drum: Literature values were obtained to get the pressure and temperature needed for an appropriate separation of the non condensables from the liquid streams. The gases obtained from the flash drum are sent as a recycle stream back to the compressor and the liquid stream are sent to distillation columns via a valve to lower the pressure to the distillation tower pressure. The temperature and pressure of the flash drum are defined in the specifications section of the flash drum as shown above. 6. Distillation Columns Group Charlie Page 43 Group Charlie Page 44 Group Charlie Page 45 7. Annotated Equipment List: Refer to the PFD for the equipment naming E-12 Air Cooler The air cooler is used between the third and fourth heat exchangers. It will cool the stream between these two pieces of equipment so that the fourth heat exchanger can use the crude methanol stream. E-4 Steam Drum This piece of equipment is the steam drum that is used for the reactor. The reactor uses saturated water to cool it and produces steam from the heat created from the reactions that occur. The steam drum sends water to a pump and receives steam from the reactor that will be condensed so it can be used again to cool the reactor. E-35 Condenser This condenser is used to turn the final grade AA methanol produced from the second distillation column into a liquid. After the methanol is in liquid form it will be sent to several storage tanks. E-32, 33, and 34 Group Charlie Page 46 These three tanks are shown in the PFD to show where the final product will be collected. Three tanks are shown, but in reality there will be a total of 11 tanks that will be able to hold the methanol product. The methanol will be at 99.85% purity, which is defined to be sold at grade AA. Heat Exchanger 1 The first exchanger is used to cool the synthesis gas from 500°F to 458°F to be used in the compressor unit. Cooling water is used on the tube side of the exchanger in order to cool the syngas. The water enters at 80°F and 20 psi, and then leaves the exchanger at 169.79°F and 20psi. This exchanger will be run at 218°psi. The heat transfer area of this heat exchanger 87.72 ft2. Heat Exchanger 2 The second heat exchanger is another shell and tube heat exchanger. It will receive the compressed syngas from the condenser and will send the gas to the reactor at a much lower temperature. The syngas will enter at 1200 psi and 716.63°F and then leave at 1190 psi and 482°F. Cooling water will be used on the tube side of the exchanger in order to cool the syngas. The heat transfer area of this exchanger is 1,119.8 ft2. Heat Exchanger 3 The third heat exchanger in the process will be a shell and tube heat exchanger. It will receive the stream from the turbo expander and sent it to another heat exchanger. The stream will consist of CO, H2, CO2, Methanol, N-Butanol, and Ethanol. The stream will enter at 648.3 psi and 424.1°F and then will be sent to the fourth heat exchanger at 638 psi and 350°F. Cooling water will be used in order to cool the stream inside of the exchanger. The hot water that is taken out of the heat exchanger will be sent into the fourth heat exchanger to be used as the cold stream. The heat transfer area of the third heat exchanger is 366.1 ft2. Group Charlie Page 47 Heat Exchanger 4 The fourth heat exchanger will take the stream from the third heat exchanger and send it to the flash column. The stream will enter at 638 psi and 350°F, and then be leaving at 638 psi and 118.13°F. The heat transfer area of this heat exchanger is 61,006 ft2. Cooling water will once again be used in order to cool the stream inside of the heat exchanger except the colder stream will be from the third heat exchanger. Pump E-36 This pump is used in order to pump the syngas received from group Delta into the first heat exchanger. Due to pressure drop in pipes, this pump is used to ensure that the first heat exchanger receives then clean syngas at the pressure specified in the heat exchanger. Pump E-5 This pump is used to pump the cooling water into the first heat exchanger. Since there is a pressure drop in piping a pump is used in order to ensure that the cooling water will enter the heat exchanger at the correct pressure. Pump E-38 This pump is used between the steam drum and the reactor. Since water is needed to cool the reactor, this pump is used to pump the water from the steam drum to the reactor. Pump E-9 This pump is used to pump cooling water into the steam drum. This is used to cool the steam that is produced from the reactor so that it condenses the steam back into water. Group Charlie Page 48 Pump E-37 This pump is used on the purge stream. It will pump the purge stream from the recycle stream to a combustion unit because there will be a large amount of CO2 in the stream and that cannot be put into the atmosphere. Pump E-10 This pump is used to pump cooling water into the third heat exchanger. After the pump the water will be at 70°F and 20 psi. Reactor The reactor is a Lurgi reactor that takes in syngas at 1190 psi and 482°F to produce crude methanol and other products. After the main reaction occurs, along with other side reactions, the product stream leaves the reactor at 1200 psi and 518°F. Since the reaction creates a lot of heat, water will be fed into the reactor to produce steam. This steam will be condensed in order to keep cooling the reactor. Inside of the reactor there will be the Cu/Zn/Al catalyst. This catalyst is used in order to keep the pressure needed to run the reaction lower than without a catalyst. Compressor block In ASPEN this is shown as one compressor, but in reality it is a multistage compressor. The compressor unit takes the syngas from the first heat exchanger at 300 psi and 458°F, and then increases the pressure to 1200 psi which is needed to run the reactor. When pressure increases so does the temperature which will leave the compressor unit at 716.63°F. In order to obtain the high pressure the Group Charlie Page 49 compressor will need to have 44,391 HP. The exiting stream from this unit will be sent to a second heat exchanger before entering the reactor. Turbo Expander Since the reactor is at such high pressure, a turbo expander is needed downstream in order to decrease the pressure quickly. The crude methanol stream from the reactor, which enters the turbo expander, will enter at 1200 psi and 518°F. After going through the expander the stream will be at 648 psi and 424°F. This exiting stream will be sent to the third heat exchanger to cool it before the stream heads to the flash column. The turbo expander will be able to drive a turbine to produce 7,726 HP, and has an isentropic efficiency of 0.72 or 72%. Flash column This piece of equipment is used to take the crude methanol stream and separate it into two streams. The stream enters the flash column at 638 psi and 118°F. After going through the column the vapor is sent back to the compressor as a recycle stream at the same temperature and pressure. The liquid stream from the flash column is sent to an expansion valve to decrease the pressure before distillation. The liquid stream is still at the same temperature and pressure but the composition of the stream is different than the vapor stream. Expansion Valve The expansion valve is used to decrease the pressure of the liquid crude methanol stream before it reaches the distillation columns. The stream enters the valve at 638 psi and 118F, and then leaves at 31.5 psi and 87.8°F. This temperature and pressure is needed for the distillation column to run effectively. E-20 and E-29 Group Charlie Page 50 These two drums are used to hold the distillate that is formed from the two distillation columns. They will hold the distillate so it can condense and then be pumped back into their respective distillation column. E-18 and 30 are reboilers E-19 and 31 are condensers Distillation Column 1 Distillation Column 2 8. Economic Evaluation Economics Windy City Methanol has faith that the project under-hand will be financeable if various contractual arrangements being negotiated with group Delta are satisfactorily executed. The complexity of the project makes it essential for credible parties, viable technology, profitable economic basis, and adequate incentives to be implemented for the project to be successful. Windy City Methanol believes it has identified all major risk areas affiliated with the project, and will provide the types of risk protection required by investors and interest parties to attain project financing. The following sections provide Group Charlie Page 51 detail on the economic sector of the project, contractual arrangements established, and type of risk Windy City Methanol anticipates. Capital Cost: The project’s earlier estimates were re-evaluated and modified to reflect more accurate figures. The largest modification to the project was utilizing a Lurgi methanol reactor as opposed to the traditional ICI quench reactor. The total equipment cost for the project is estimated to be slightly over $43 million. The following table shows a breakdown of the capital costs including a contingency reserve allocated for any fiscal disparities during the construction of the Windy City Methanol plant. The funds required to complete the Project are estimated below (in US dollars). The installation factor figures were obtained from the “Plant Design and Economics for Chemical Engineers” by Peters & Timmerhaus. Total Installed Costs Equipment sub-total $ 43,969,504 Direct Costs Factor Cost Piping 0.68 29,899,262 Instillation 0.47 20,665,667 Buildings 0.18 7,914,511 Electrical installation 0.11 4,836,645 Group Charlie Page 52 Service facilities 0.70 30,778,652 Controls and valves 0.36 15,829,021 Subtotal 109,923,760 Indirect Costs Factor Cost Construction Expenses 0.41 18,027,496 Supervision and Engineering 0.33 14,509,936 Legal Expenses 0.04 1,758,780 Contingency 0.44 19,346,581 Subtotal 53,642,794 Total Capital Investment 207,536,058 Please see “economic tables” for a detail breakdown of all the capital costs and descriptive equipment list. The following table shows the low and high ranges of capital costs based on cost estimation (in millions of US dollars). Low Likely High Plant Cost 207 209 300 Vessel Cost 22 32 35 Group Charlie Page 53 Land Cost (75 acre) 28 37 75 Total 257 278 410 Windy City Methanol estimates the total cost of the Project will be approximately $245 million and the loan attained by a reputable bank will be used to finance 100% of the cost during the construction period. Upon completion of the plant, approximately $61 million of the equity from the owners will be used to reduce the outstanding bank debt. The remaining $184 million debt will be repaid over the next 19 years of the plant life. The sole purpose of financing the cost of designing, building and equipping the Windy City Methanol plant is to construct a facility capable of producing 3,200 TPD of grade AA methanol. The plant will be build over a 75 acre field located in Gary Avenue Indiana near Delta’s gasification plant thus eliminating the transportation cost of the feedstock. Syngas will be supplied under a long term contract and the methanol will be sold under a long term agreement with a reputable, major US company. All necessary authorizations and design specifications, including all relevant infrastructure development essential for normal operations for the project will be attained by the end of the test period. Windy City Methanol believes that equity investors will be seeking a minimum internal rate of return in the range of 16%-18% per annum. This minimum return is obtained at a methanol price of $ 1.35 per gallon, and $ 200 per ton of feedstock. Sensitivities and Assumptions: The financial model is structured to reflect a realistic and feasible undertaking. The project model is developed within the following parameters. Group Charlie Page 54 Selling price of methanol is $1.35 per gallon Feedstock price of syn-gas is $ 200 per ton Tax rate is 40% Inflation rate is 0% Contingency is $ 19 million Total costs are $ 245 million The internal rate of return (IRR) has be computed for three methanol prices; the results are shown below: Price of Methanol Cost of Syn-gas Feedstock (dollars/ton) dollars/gal $200 $250 1.35 (base price) 16.00% 6.73% 1.50 41.68% 34.90% 1.75 96.30% 69.62% Windy City Methanol believes a 16-18% IRR is highly attractive return for equity investors. The table shows that this is easily attainable for all cases except for the scenario where the syngas feedstock costs Group Charlie Page 55 $250/ton and the methanol price is $1.35 per gallon. Based on historic methanol market prices patterns, Windy City Methanol believes that a market price of $ 1.35 per gallon is realistic since there is increased demand with limited world supply. A futuristic increase in methanol market prices is highly promising since crude oil price is highly susceptible to political turmoil and is a limited resource. Risk Profile Market Risk: Inaccurate demand estimates. The selling price of methanol is not economically feasible for the project. Protection: Attain a long term methanol purchase contract with a large, creditworthy US Corporation. Syngas Supply Risk: Inaccurate supply estimates. The price at which syngas is bought is not economical for the project. Protection: A long term syngas supply contract with a fixed price and a pledge of adequate MSW reserve to meet contractual agreement between Windy City Methanol and Group Delta. Group Charlie Page 56 Construction Risk: Construction overruns due to factors such as poor cost estimates, inflation, and construction delays caused by environmental or regulation mishaps. Overruns can cause funding problems and make the project uneconomical. Protection: Fixed price contract agreements. Orchestrate several feasibility studies on cost estimates and implement stringent construction deadlines. Operational Risk: Operation interruption caused by various situations such as plant failure, malfunctions, prolonged maintenance and repair, and natural disasters. Protection: Have business interruption insurance to pay debt caused by plant failure or natural disaster. Legal Risk: Long-term contracts among twp parties can result in legal disputes. Protection: Attain high-quality legal advice. Have a devisable dispute settlement mechanism. Labor-related Resources and Technical Feasibility: Group Charlie Page 57 Special skills are essential for a planned project; therefore, specific skill required for the Windy City Methanol plant are listed below. Personnel Description Number Annual Salary Subtotal Plant Operating Crew: Operator 6 $40,000 $240,000 Lab Tech. 2 $30,000 $60,000 Mechanical Tech. 2 $35,000 $70,000 Process Engineer 4 $60,000 $240,000 Electrical Tech 1 $35,000 $35,000 Shift Supervisor 2 $45,000 $90,000 Maintenance 2 $40,000 $80,000 Superintendent 1 $100,000 $100,000 Plant Manager 1 $80,000 $80,000 Total: 21 Administration: $995,000 *plant operating crew will have two 12-hour shifts to provide 24-hour coverage Group Charlie Page 58 Each personnel salary is based on accurate, current, and reputable pay-scales salary calculator websites in the Indiana state area and was validated by comparing other similar salary calculator sites. The salary figure median was taken into account and implemented in the cost estimation section of this report. 9. Utilities Throughout the process there is a lot of cooling water needed along with electricity. Each piece will need electricity to run, and power is also needed to run all of the temperature and pressure controls. There will also need to be a facility to treat the cooling water needed in the heat exchangers. The overall process will need 13,349.36 gallons/hr of cooling water, along with _____ MW/day of electricity. The process will also require 132898.47 pounds of steam/hour. Steam is needed for the reactor. 10. Conceptual Control Scheme The following figure shows the overall control scheme for the process. Group Charlie Page 59 11. General Arrangement Process equipment arrangement and plant layout must be carefully analyzed before construction of a new facility can begin, because these factors affect nearly every aspect of plant design and operation, including: land requirements, permits, safety systems, construction, piping arrangements and costs, operating costs, and future expansion. The location of the plant must be chosen prior to plant layout because specifics such as average wind direction, and access to roads cannot be determined without a Group Charlie Page 60 plant location. The area chosen for the methanol plant is in Gary Indiana, just north of Gary Ave, which can be seen in the image below. This location provides several advantages because it allows access to nearby Hwy 90 for ease of transportation via freight, and is situated across the street from Group Delta’s syngas plant. The proximity to the syngas plant is important because the syngas could be piped underground directly into the methanol plant, significantly reducing transportation costs. It was discovered that at this geographic location, the most common wind direction is the southwest to the northeast. It is important because anywhere that there is an open flame must be upwind of any Group Charlie Page 61 flammable materials. This was used in the placement of the ground flare at the methanol plant which is used to burn off unusable flammable materials. The location chosen for the ground flare was at the southeast corner of the facility, so that the most common wind direction does not have the possibility of blowing the flames of the ground flare towards the syngas and methanol storage tanks. The plant layout itself was derived from the process flow diagram, and implemented into the chosen location of the facility. The dimensions of the facility are 156ft by 775ft. Access will be provided through an entrance at Cline Ave, which will lead to the west side of the facility. Visitors and employees will be greeted by security officials at the gatehouse, and those granted access will be able to park in one of the two available parking lots. The main offices are located in the northwest corner of the main production building, and control rooms are located just south of the offices. The main production building also houses the methanol synthesis components including: heat exchangers, flash drums, compressors, turbo expanders, and the reactor. The main pipe rack is easily accessible to every piece of equipment because it runs directly down the center of the building. The two distillation columns are located outside the building on the east side. Storage tanks line the northern edge of the facility, with plenty of area between the building and the tanks for easy access for tractor trailers. The specifics of the plant layout can be seen in the image below. Group Charlie Page 62 Wind Direction 12. Distribution and End-use Issues review The global market for methanol is forecasted to reach nearly 55.3 million metric tons by the year 2015. This is mainly due to the growing consumption of methanol in Asia-Pacific, specifically in China. A key factor that leads to the growing consumption of methanol is its use in alternative fuels and the production of acetic acid. The three largest derivatives of methanol are formaldehyde, methyl tertiary butyl ether (MTBE) and acetic acid. Methanol consumption in gasoline blending, especially in China, has grown significantly over the last few years, with this use accounting for approximately 7% of world methanol consumption. This is mainly due to Beijing settling on a national standard for methanol as an automotive fuel. China uses nearly 3 million tons of methanol, which gets blended yearly into the gasoline market. Just as the Group Charlie Page 63 United State uses E85 for cars that use ethanol blended with gasoline, the Chinese will be using M85, to represent the use of methanol and gasoline. The numbers in these labels represent the use of 85% methanol or ethanol and 15% gasoline. Methanol can be used in a variety of industrial applications. Its largest use is as a raw material for the production of methyl t-butyl ether (MTBE), a gasoline additive. MTBE is manufactured via the chemical reaction of methanol and isobutylene. MTBE is used as an oxygenate to raise the octane number in gasoline. MTBE is favored over ethanol because of its superior performance in reducing benzene and formaldehyde in gasoline, and its lower volatile organic compound content. It is also used in organic chemistry as a relatively inexpensive solvent with properties comparable to diethyl ether but with a higher boiling point and lower solubility in water. We will be specifically targeting companies that require methanol as a use to produce MTBE. Some of these companies include Amoco and Citgo. There are 27 companies producing methyl-tert-butyl ether at 32 facilities in the United States, with these two companies included. Methanol is also used in the production of formaldehyde, chloromethanes, methyl methacrylate, methylamines, dimethyl terephthalate, and as a solvent or antifreeze in paint strippers, aerosol spray paints, wall paints, carburetor cleaners, and car windshield washer compounds. Formaldehyde accounts for about 36% of the estimated methanol demand; it is used in resins for buildings materials and the wood products and in the construction of housing, commercial and industrial structures, laminates in the furniture industry and engineering plastics in the automotive industry. Acetic acid represents 11% of total demand. Vinyl acetate Group Charlie Page 64 (VAM), a derivative of acetic acid, is used in the manufacture of paints, adhesives, film, paper and textiles and is the largest and fastest growing consumer of acetic acid. The methanol produced at this particular power plant will have a purity of 99.85%, which will qualify it to be sold as grade AA methanol. There are several requirements that need to be met in order for it to be called grade AA methanol. The amounts of acetone and aldehyde can only be at max 30 wt-ppm. Acetone and ethanol can only be present at a max limit of of 10 wt-ppm and there also cannot be any higher alcohols present. Finally, water must be only present at maximum limit of 1,000 wt.-ppm. In the long run methanol is being researched as a source of hydrogen for fuel cells used in transportation, stationary power generation, and portable power applications. Many recent U.S. patents and patent applications involve methanol fuels cells. Some of the technologies patented for methanol cells include: anode structures, catalysts, membrane assemblies for direct cells, and sensor-less optimization of methanol concentration in a cell. 13. Constraints Review 1. Feedstock definition: Feedstock will be taken from group Delta that produces syngas from municipal solid waste. 5000 tons per day of municipal solid waste will be gasified using a plasma gasifier Group Charlie Page 65 to produce syngas. The final product, feedstock to this process, will be syngas with a 2:1 ratio of H2 to CO at 1700 tons per day (141666.662 lb/hr) at 500 psi and 700 ºF. 2. Conversion technology description: The conversion technology used in this process is in the face of a chemical reactor. A Lurgi reactor is used to synthesize methanol from synthesis gas. A Lurgi reactor works as a shell and tube heat exchanger. The reaction takes place in the shell side while cooling water (that evaporates into steam) runs tube side. The catalyst covers the outside of these tubes and since this is the hottest part of the reactor heat is efficiently extracted from the reactor in the form of high pressure steam. In the 1900s catalysts were not perfected to methanol synthesis and this resulted in very high reaction temperatures and pressures. Pressures as high as 2000 psi were not uncommon and temperatures exceeding 800 F were required, the introduction of the Cu/Zn/Al catalyst for methanol synthesis has rid us the need to compress the reactants at such high pressures. Today these catalysts have allowed saving a lot of money on the compression and temperature costs. Pressures as low as 700 psi have been employed for methanol synthesis but increasing pressures result in a better conversion of CO to methanol. 3. Separation technology description: The separations train includes the flash drum and two distillation columns. The flash drum operates at 638 psi and 118.13 F. It is basic flash technology where the lower pressure lets the vapor evaporate and go off in a vapor stream. The liquid is let out in the bottom. The distillation columns also do not employ any special technology. There are basic stages and separations takes place based on the efficiencies of the trays. Energy produced in the reactor is recycle in the distillation columns, the re boiler employs this energy. 4. Product Description: Group Charlie Page 66 Grade AA methanol is being produced in this process, this is methanol with a purity of 99.85 wt%. 5. Location Sensitivity Analysis: 6. ESH law compliance: Methanol Storage and Handling The most common ways of transporting methanol is through bulk transportation, which includes rail, truck, and pipelines. During transferring or storage, the systems should be cleaned, flushed, and sampled in order to ensure integrity of the product. Materials and methods of construction must be compatible with methanol service. Methanol is non-corrosive to most metals at ambient temperatures, except to lead, magnesium, and platinum. Mild steel is usually selected as the construction material. Also, coatings of copper, zinc, or aluminum are attacked slowly by methanol. Preferred methods of methanol service include, nylons, rubber, particularly nitrile and ethylene propylene rubber. Teflon and neoprene are also preferred components of equipment in methanol service. Storage tanks of welded construction are considered satisfactory for methanol. They should have secondary containment such as dikes to reduce fire or prevent large spills. Large tanks should have control devices such as level gauges, conservation vents, and pressure vacuum relief valves. Sources of Exposure to Methanol Inhalation of methanol vapors is the most frequent exposure. The methanol threshold limit value is 200 ppm. This is the maximum average concentration a worker should be exposed to over a eight hour period. The short term exposure limit is 250 ppm. This is the maximum average concentration a worker should be exposed to over 15 minute periods, four times per day with at least 60 Group Charlie Page 67 minutes between exposure periods. Methanol can also be ingested orally. One to four ounces of methanol have been known to cause fatalities. There are no serious effects from skin contact to methanol as long repeated and excessive exposures are avoided. Personal protective equipment should be used in the presence of exposure to methanol. This can include appropriate footwear, face shields, respiratory protection, or chemical suits. Methanol is labeled as a Class 1B flammable liquid by the Occupation Safety and Health Administration (OSHA). Pure methanol has a flash point of 12°C. Flash point is defined as the minimum temperature at which the vapour pressure of a liquid is sufficient to form an ignitable mixture with air near the surface of the liquid. The lower explosive limit (LEL) of methanol is 6% by volume and the upper explosive limit (UEL) of methanol is 36% by volume. The UEL corresponds to a methanol temperature of 41°C. In order to deal with the flammability of methanol, many precautions have to be considered. Smoking must be prohibited, grounding is required for all equipment, including tanks, pipe racks, pumps, vessels, and filters. Ventilations must be sufficient to cope with the maximum expected vapor levels in the buildings. There will be relief valves in place on distillation columns, flash drum, and reactor. All controls can be viewed under the control scheme section of this report. Another safety hazard in this plant is the amount of CO that will be released. A thermal oxidizer will be used to destroy hazardous air pollutants and volatile organic compounds. They will be destroyed via thermal combustion and eventually changed to form CO2 and water. CO2 will also be released from distillation column 1 in the distillate stream at an amount of 23,180.57 lb/hr. Precautions muse be taken to ensure there no leaks and that the CO2 is successfully released into the atmosphere and not built up inside the buildings. 7. Law of physics Compliance Group Charlie Page 68 8. Turn Down ration A turn down ratio of 50% was used to prevent clogging of pipes and equipment. This number is very common in the methanol industry and is often seen in literature 14. Applicable Standards Talk about Grade AA Methanol. Can discuss EPA standards for the whole process and that no waste is being produced and everything is being oxidized in a thermal oxidizer. 15. Project Communications File To view any more information about the process and the components, visit http://charlie497.wikispaces.com. This site can be used to view all files and references used in the research of our process. Any questions that arise about the process can be answered within the wiki site. Group Charlie Page 69 16. Information Sources and References "Gulley News Page 2002." Homepage.jpg. 2011. Web. 23 Apr. 2011. <http://www.gulleyassociates.com/news2002.htm>. Law , Nicole, Caitlin Nichols, and David Tamayo. "Final Report: Methanol Synthesis." Chemical Engineering Program (2008): 11-14. Web. 2 Mar 2011. Amirkhas, Elton, Raj Bedi, Steve Harley, and Trevor Lango. "Methanol Production in Trinidad and Tobago." Final Report (2006): 7-8. Web. 2 Mar 2011. Grue, J; Bendtsen, J.D. Synthesis and Optimisation of a Methanol Process. Paper presented at 44th Scandinavian Conference on Simulation and Modelling, 2003. Group Charlie Page 70