Alternative Fuels: The industrial gas turbine

Investigation of alternative fuels for industrial muff turbines Tamal Bhattacharjee, Paul Nihill, Cormac Bulfin, Ishank Arora Contents 1. Abstract4 2. Introduction4 3. enthalpy5 3. 1Production5 3. 1. 1 go Reforming of Hydrocarbons5 3. 1. 2Water Splitting5 3. 1. 3 bollixification of Waste & Biomass to make believe syn sport6 3. 1. 4The surgical operation7 3. 1. 5Application to industrial shooter turbines8 4. wood alcohol9 4. 1Abstract9 4. 2Introduction9 4. 3History10 4. 4Manufacturing Process10 4. 4. 1 Production of wood alcohol from deductive reasoning gas10 4. Industrial Process11 4. 5. 1STEP-1 corrode Production11 4. 5. 2STEP-2 Reforming11 4. 5. 3STEP-3 wood alcohol Synthesis12 4. 5. 4STEP-4 M neutral spirits Purification12 4. 6How it works on a gas turbine12 4. 7Feasibility15 4. 8Advantages & Disadvantages16 4. 9Conclusion17 5. place Alcohol17 5. 1Introduction17 5. 2Chemistry18 5. 3Production18 5. 3. 1Ethanol from sugar shadowere18 5. 3. 2Fermentation18 5. 3. 3Distillati on19 5. 3. 4 incomplete Distillation19 5. 4Air pollution21 5. 5Advantages23 5. 6Disadvantages23 6. References24 1. AbstractThe industrial gas turbine is a key sectionalization of new-fashioned electricity generation. In 1998 15% of electric antecedent was produced by gas turbines. Due to their expertness, compactness, reliability and relatively low gear capital cost 81% of new electric power demand will be met by industrial gas turbines. Gas turbines must meet in truth strict dark CO and carbonic acid gas regulations. (GL Juste 2006). As the popularity of gas turbines and combined affectionateness and power generation embeds increases interrogation has turned to cheaper and more milieu solelyy friendly fuels for gas turbines.Methane C2H4 is the main(prenominal) fossil fuel utilised in gas turbines today unless with increased regulations on carbon firing offs combined with the increasing cost of fossil fuels, research is turning to alternative fuels which may power gas turbines into the future. This literature review explores dominance liquid and gas alternative fuels for industrial gas turbines along with whatsoever of the latest research in the ara and some examples of the successful industrial applications. 2. IntroductionThe increasing cost of fossil fuels, the fact that they are a finite alternative and the environmental effects of their combustion means that research into alternative fuels is one of the largest and most varied areas of scientific investigation in progress today. As with all scientific research, some will be successful and form the basis of future energy achievement and some will be either in any case inefficient or impractical to be implemented in industry. It is interesting to none that some of the methods which seemed impractical even 10 years ago are now being introduced owing to the increasing cost of fossil fuels.Fuels derived from biomass and gasification of sewage sludge and municipal swash and some methods of hydrogen fuel fruit pop to hold the most see to it. Different global energy scenario studies indicate that in India biomass may contribute oft more up to 30% of the energy proviso by 2100 (K. K. Gupta et al 2010) Gas turbines and combined hotness and power (CHP) trunks are at the forefront of future European strategies on energy yield with electric current efficiencies for combined cycle facilities above 60%. The main CHP targets are the reduction of the overall costs and the development of above 40 kW biomass-fired systems..Gas turbines enjoy veri dishearten(prenominal) merits relative to steam turbines and diesel engines. They pack high grade bollocks disembowelion, lower weight per unit power, dual fuel capability, low maintenance cost, low vibration levels, low capital cost, compact size, short delivery time, high flexibility and reliability, fast starting time, lower manpower, and have better environmental surgery. (P. A. Pilavachi et al 2000) This project foc uses on alternative fuels as applied to industrial gas turbines owing to their projected increase in popularity in the short to medium precondition at least. 3. Hydrogen 3. 1Production 3. 1. move Reforming of Hydrocarbons The bulk of hydrogen fuel production is currently via steam reforming of natural gas this emergence involves the reaction of natural gas or liquid hydrocarbons with high temperature steam to produce varying amounts of CO and H2. Steam reforming of hydrocarbons does non eliminate CO2 but it greatly reduces the amount which is accomplish into the atmosphere. Steam reforming of hydrocarbons is an efficient way of reducing CO2 emissions. In addition to the H2 produced during gasification a low temperature gas alternate reaction with the remaining carbon monoxide merchantman produce further H2.The sue of steam reforming natural gas along with the gas shift reaction are governed by the chemical substance equations below. (K. K. Gupta et al 2010) Steam Reforming C H4 + body of water CO + 3H2 ? H = +251 kJ/mol Gas Shift CO + H2O CO2 +H2 ? H= -42 kJ/mol (K. K. Gupta et al 2010) The release of CO2 stop be completely eliminated in a large build where the CO2 is captured and injected into an cover or gas reservoir. It is currently disputed between scientists whether or not the production of H2 in this way releases more CO2 than directly burning fossil fuels. 3. 1. 2Water SplittingThere is currently a lot of research concerning the fragmentizeting of weewee to produce H2. This method is yet to find industrial application as it takes a lot of energy to split pissing and the only sustainable method is the use of renewable technologies to provide the energy. The hydrogen is more likely to be used as a storage medium when the power generated by renewable technologies is not required. An example of this would be the storage of power from a wind turbine during the day. There is a lot of very interesting research into water-splitting with many me thods being explored simultaneously.Thermo chemical water splitting using solar power is an interesting option. Direct thermal water splitting is impractical imputable to the energy requirements to heat the water to 25000K. But if the water is reacted with metal oxides and redox materials it tail assembly be achieved at a much lower temperature. The oxygen and hydrogen are released at assorted arranges eliminating the use up for separation. This surgical process can be conducted in a cycle that produces H2 more efficiently from solar radiation. 3. 1. 3Gasification of Waste & Biomass to produce syngasA Practical Example of waste to energy conversion is the Pyromex waste to energy facility in Germany. The Pyromex system is currently being used successfully to gasify industrial waste in a purpose built plant in Munich Germany. Due to the fact there are no gaseous emissions from the system there is no need for the construction of smoke stacks and the system is considered separate t o incineration by EU authorities. Emissions from the plant are in the form of solid sand like change waste. The waste composition is tabulated below and shows how far below allowable limits the process is.The raw material in the process is otherwise unrecyclable waste products and the system can treat sewage sludge, plastics, fly ash from power plants and various other waste products. The system has the potential to be a major contributor to the Hydrogen Economy. The prototype plant working on a through and throughput of 25 ton/day had the potential to produce approximately 2150 kWh by a combined heat to electricity and syngas engine generator system. If used in combination with an industrial gas turbine there is no doubt that owing to the greater efficiency this power fall output could be improved.Fig. 1 Exhaust gas emissions (Pyromex) 3. 1. 4The process The material to be gasified is introduced into the slowly turning reactor through a dickens stage tank system. With this da nce orchestraup an oxygen free environment can be ensured inside the reactor pipe, where the conversion of the organics to syngas takes place at over universal gravitational constantC. The produced gas is then cleaned with a simple acid and an alkaline scrubber. Even though the temperatures within the reactor are far above 1000C, the heighten remains cool enough to be touched by hand.The PYROMEX gasification is a closed circuit process and therefore no emissions are released into the environment. The process fall down chart below gives a better understanding of the workings of the plant. This process can be advantageously scaled. And there are numerous plants completed and in the process of construction in Germany and the U. S. Fig. 2 Gasification process of producing syngas from waste & biomass (Pyromex) 3. 1. 5Application to industrial gas turbines Once the hydrogen has been produced it can be mixed with carbon monoxide which can alike be produced efficiently using solar pow er.This syngas can be used in an Industrial gas turbine with some modifications to the fuel nozzle system and careful control of the fuel air ratio to produce electricity. In the case of liquid fuel turbines the hydrogen can be converted to various hydrocarbons using the Fischer-Tropsch process. The use of hydrogen in a gas turbine is a relatively new concept with the use of high hydrogen meaning syngas decent an attractive area for research. Unfortunately the use of hydrogen rich gas in a conventional gas turbine involves some tweaks to the ystem. The natural gas lean-premixed combustors have to undergo some modifications if fed with hydrogen rich fuels due to the combined effect of hydrogen shorter auto-ignition stand up and faster flame speed. (Paulo Gobbato et al 2010) One of the routes with the highest potential is the pre combustion route utilizing coal in an integrated gasification and combine cycle (IGCC). The challenge in utilizing hydrogen rich fuel is principally assoc iated with its reduced auto-ignition delay time, which can be addressed in one of three approaches 1.De-rating the engine allowing the aforesaid(prenominal) commixture time by increasing the auto-ignition delay time through altering the characteristics of the vitiated air (i. e. the inlet temperature of the flow to the SEV). 2. Decreasing the responsiveness of the fuel i. e. by dilution with an inert gas. 3. Modifying the hardware either to reduce the mixer abode time in line with the reduced auto ignition delay time or develop a concept which is less influenced by the reactivity of the fuel. (Nils Erland et al 2012) 4. Methanol 4. 1Abstract 5.When wood alcohol is intended to be used as fuel for gas turbine, it is very important to enhance overall thermal efficiency of the gas turbine system, and to make it competitive with conventional oil or gas fuels. There are many ways to accomplish this. Combined cycle is not, however, a proper way, as this could likewise be applied to conventional fuel. Noting the unique characteristic of methyl alcohol, the steam reforming regenerative cycle was investigated by many institutions. In this scheme, wasted heat of the gas turbine exhaust gas is transferred to reformed gas.And it is recycled back to the gas turbine as a part of fuel, thus resulting in increased overall efficiency of the gas turbine. Thermal decomposition of methyl alcohol is also an endothermic reaction and may be applied to the regenerative cycle. In either case, however, only a part of the waste heat is recovered. Hence the hybrid system with combined cycle was proposed to achieve additional heat recovery. But this is a complex system. 4. 2Introduction 6. Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH. . 8. Fig. 3 Chemical formulation of Methanol 9. Methanol can be used as alternative fuel in gas turbine. Methanol is made from natural gas, coal, and biomass. This was one o f the older alternative fuels. Like Ethanol, Methanol is very good for blending with gasoline to replace the harmful octane enhancers. The benefits of using Methanol are that it reduces emissions, which has a significant effect on bettering the environment. Methanol can easily be blended with gasoline. It also has a lower risk of flammability than normal gasoline.Another benefit of Methanol is that it is made from domestically renewable sources. Methanol can also be used to make the octane enhancer MTBE. Another huge possible benefit of Methanol is that it can be made into hydrogen. 10. 4. 3History 11. Methanol has been tested as a gas turbine fuel in the U. S. In 1974, a 12-hour test was conducted by Turbo Power and Marine in a 20 MW gas turbine at the Bayboro Station of Florida Power Corporation. The methyl alcohol was fired as a liquid. nighttime emissions were 74% less than those from No. 2 Distillate, and CO emissions were comparable (Power 1979).In 1978 and 1979, EPRI and Sou thern calcium Edison Company sponsored a 523-hour test at SCEs Ellwood Energy Support Facility, using one half of 52 4. 4Manufacturing Process 4. 4. 1 Production of methanol from synthesis gas 12. Carbon monoxide and hydrogen react over a catalyst to produce methanol. Today, the most widely used catalyst is a mixture of Cu (Copper), zinc oxide, and alumina first used by ICI in 1966. At 510 M Pa (50100 atm) and 250 C, it can turn the production of methanol from carbon monoxide and hydrogen with high selectivity (99. 8%) 13. CO + 2 H2 CH3OH..It is worth noting that the production of synthesis gas from methane produces three moles of hydrogen gas for every mole of carbon monoxide, while the methanol synthesis consumes only both moles of hydrogen gas per mole of carbon monoxide. One way of dealings with the excess hydrogen is to inject carbon dioxide into the methanol synthesis reactor, where it, too, reacts to form methanol according to the equation 14. CO2 + 3 H2 CH3OH + H2O. 15 . Some chemists believe that the certain catalysts synthesize methanol using CO2 as an intermediary, and consuming CO only indirectly. 6. CO2 + 3 H2 CH3OH + H2O where the H2O byproduct is recycled via the gas shift reaction 17. CO + H2O CO2 + H2, 18. This gives an overall reaction, which is the same as listed above. 19. CO + 2 H2 CH3OH 4. 5Industrial Process Fig. 4 Industrial process for creating Methanol 4. 5. 1STEP-1 Feed Production 20. The two main two feed stocks, natural gas and water, both require purification before use. Natural Gas contains low levels of process compounds and undergo a desulphurization process to reduce, the sulphur levels of less than one part per million.Impurities in the water are reduced to undetectable or parts per one million million million levels before being converted to steam and added to the process. If not removed, these impurities can result in reduced heat efficiency and significant damages to major pieces of equipment. 4. 5. 2STEP-2 Refo rming 21. It is the process which transforms the methane and the steam to intermediate reactants of hydrogen, carbon-dioxide and carbon monoxide. Carbon dioxide is also added to the feed gas stream at this stage to produce a mixture of components in the exemplar ratio to efficiently produce methanol.This process is carried out in a Reformer furnace which is heated by burning natural gas as fuel. 22. reception Reaction 4. 5. 3STEP-3 Methanol Synthesis 23. After removing excess heat from the reformed gas it is compressed before being sent to the methanol production stage in the synthesis reactor. Here the reactants are converted to methanol and separated out as a bumpy product with a composition of methanol (68%) and water (31%). Traces of byproducts are also formed. Methanol conversion is at a rate of 5% per pass hence there is a continual cycle of the un- reacted gases in to the synthesis loop. 24.Reaction 25. 4. 5. 4STEP-4 Methanol Purification 26. The 68% methanol solution is purified in two distinct tramples in tall distillate columns called the surpass column and refining column to yield a meliorate product with a purity of 99% methanol classified as Grade AA refined methanol. 27. The methanol process is tested at various stages and the finished product is stored in a large secured tank age area off the plant until such time that it is ready to be delivered to customers. 4. 6How it works on a gas turbine 28. Chemical reaction involved is It reacts with water to form carbon di oxide (CO2) and hydrogen (H). 9. CH3OH + H2O = CO2 + 3H2 30. The reaction is endothermic and absorbs waste heat at about 300oC. The system performance was predicted using in house process simulator called CAPES and launch thermal efficiency of approx. 50% (LHV) when turbine inlet temperature is 1,100oC and compression ratio is 14. The schematic diagram given below illustrates its function. 31. 32. Fig. 5 Methanol fueled gas turbine process 33. 34. The performance of the gas turbine with steam reforming was recalculated using PRO/II. The same adiabatic efficiency of 87% for compressor and 90% for turbine were used.Similar value of overall thermal efficiency of approx. 50% was obtained as shown in Table-1. For reference, the performance of air heating system was also investigated. In this case, thermal efficiency was in the same level as reforming but total heat transfer area is 1. 7 times of steam reforming case. Lets explain model making of steam reformer by PRO/II. After defining stoichiometric data for steam reforming reaction, Gibbs reactor was used for equilibrium calculation at specified temperature. For combustor design, two combustion reactions were defined.Then two conversion reactors were connected in series and set the conversion parameter to 1. Both reactors are defined as adiabatic. 35. Heat exchangers having phase change were split into 10 to 20 zones and flow configurations were set to true counter flow. Minimum pinch points were set to 1 0 to 20 oC. Pressure drop of each exchangers were set to 0. 02-0. 01 atm and overall heat transfer coefficient were set to100kcal/h C. Flow Scheme unit Fig-1 Fig. -2 Waste Heat Recovery Air Heating & Methanol Evap. Steam Reforming, Water Injection & Methanol Evap. Turbine Inlet Temperature oC 1,100 1,100 Compression Ratio - 14 14 Methanol swan kgmol/h 0. 133 0. 133 Stoichiometric Air Rate kgmol/h 1 1 Air Rate kgmol/h 4. 150 2. 600 Reforming Water Rate kgmol/h - 0. 133 Total Water Rate kgmol/h - 0. 720 excessiveness Air Mol Ratio - 4. 150 2. 600 Water/Air Mol Ratio - 0. 000 0. 277 Water/Methanol Mol Ratio - 0. 000 5. 414 1st Compressor Power kW -12. 472 -7. 814 1st Turbine Power kW 24. 128 19. 750 Water Injection Pump kW - -0. 006 Net Shaft Power kW 11. 656 11. 930 Power Output kW 11. 423 11. 691Methanol Heat of Combustion (HHV) kW 47. 149 23. 574 Methanol HHV kJ/mol 638. 10 638. 10 Overall Thermal Efficiency (HHV) % 48. 45 49. 59 Compressor Adiabatic Efficiency % 87 87 Turbine A diabatic Efficiency % 90 90 Generator Efficiency % 98 98 Methanol Evaporator commonwealth/Pinch Point m2/oC 0. 140/10 0. 138/5 Methanol Reformer Area/Reaction Temp. m2/oC - 0. 201/300 Air Heater Area/Pinch Point/Max. Temp. m2/oC 2. 972/10/525 0 Water Evaporator Area/Pinch Point m2 - 1. 452/10 Total Surface Area m2 3. 112 1. 791 Exhaust Temperature oC 335. 3 102. 5 Table 1 Methanol Fuel Gas Turbine with Steam Reforming & Water Injection or Air Heating 4. 7Feasibility 36. MW, twin engine, gas turbine generator unit supplied by Turbo Power and Marine Systems, Inc. (Edison Co. 1981). The methanol was fired as a liquid. Some fuel system modifications were performed to permit the higher mass and volumetrical flow of methanol to achieve base load output. Some elastomers in the fuel system were replaced with materials impervious to methanol attack. The tests showed Operations on methanol are as flexible as on natural gas or distillate fuel.The ability to start, stop, accelerate, deceler ate, perform automatic synchronization, and respond to control signals is equal to operations on either natural gas or distillate fuel. Turbine performance on methanol is improved over other fuels due to higher mass flow and the lower combustion temperatures resulting from methanol operations. Oxides of nitrogen emissions on them ethanol-fueled turbine, without water injection, were approximately 80% of the emissions of the distillate-fueled turbine with water injection. There was a significant reduction in particulate emissions during methanol operation.An additional reduction in oxides of nitrogen emission was obtained during operations of the methanol-fueled turbine with water injection. No significant problems occurred during the test that could be attributed to methanol. The hot end inspection indicated cleaner components within the methanol-fueled turbine. During 1984-1985, GE conducted methanol combustion tests of heavy-duty gas turbine combustors in a private study for Cela nese Chemical Company, Inc. This work is unpublished. The tests were conducted at GEs Gas Turbine. Development Laboratory in Schenectady, N . Y.Tests were performed with an MS6001B full-scale combustor representative of GE heavy-duty gas turbine combustors, and an MS7001 developmental prohibitionist low NOx combustor. Then ethanol was fired as a liquid, dry and also with water addition. A high- twinge centrifugal pump was used to run the methanol to the combustor. The tests demonstrated that methanol fuel can be successfully burned in GE heavy-duty combustors without requiring major modifications to the combustor. NOx emissions were approximately 20% of those for the same combustor firing NO. 2 distillate at the same firing temperature.With water addition, NOx levels of 9 ppmv could be achieved. Liner metal temperatures, exit pattern factors, and dynamic pressures were not significantly affected by methanol combustion and met GE criteria for acceptable performance. The results are valid for 2000 F firing temperature machines (E-class). Additional work would be required to confirm performance with methanol fuel, tall firing temperatures of the F series of machines. Vaporized methanol will reduce NOx 5% to 10% (relative to CH4 emissions) whereas liquid methanol will reduce NOx 30% relative to CH4 emissions.Water content in the methanol provides further NOx reduction. In 1984, a field test demonstration was performed at the University of California at Davis (California Energy Commission 1986). Methanol was fired in a 3. 25 MW Allison 501-KB gas turbine for 1,036 hours. Low NOx emissions were observed and were further reduced by mixing water with the methanol. Problems encountered with the traditional gas turbine fuel pump were bypassed by using an off-board centrifugal pump. 4. 8Advantages & Disadvantages 37. Methanol is a liquefied form of methane, a naturally-occurring gaseous hydrocarbon produced by decomposition.Currently, methane is burned as a waste gas at oil drilling platforms, coal mining sites, landfills, and sewage treatment plants. The advantage is methane, and its derivative methanol is that it is extremely plentiful drilling for oil, mining coal, and the decomposition of organic matter all produce methane already. As a hydrocarbon similar to propane and petroleum, methane is a very powerful, detonative gas that can easily take the place of petroleum without marked decline in power or major retooling of existing technologies.The disadvantages of methanol is the process by which methane is converted into a liquid at normal temperatures by mixing methane with natural gas and gasoline, methane is converted into methanol. But the need for gasoline does not entirely wean the United States off of oil, so its alternative status is questionable. Additionally, the process to capture, store, and convert methane is prohibitively expensive compared to gasoline. 38. 4. 9Conclusion 39. Methanol is considered a superior turbine fuel, with the promise of low emissions, excellent heat rate, and high power output.The gas turbine fuel system must be modified to accommodate the higher mass and volumetric flow of methanol (relative to natural gas or distillate). The low flash point of methanol necessitates explosion proofing. The low flash point also dictates that inauguration be performed with a secondary fuel such as distillate or natural gas. Testing to date has been with methanol as a liquid. GE is comfortable with methanol as a liquid or vapor. GE is prepared to make commercial offers for new or modified gas turbines utilizing methanol fuel in liquid or vapor form based on the earlier experience.Some combustion testing may be required for modern machines applying for very low NOx permits. 5. Power Alcohol 5. 1Introduction Power Alcohol is a mixture of petroleum and ethanol in contrary proportions and due to these proportions different names are given to each blend like- 1. As a blend of 10 pct ethanol with 90 percen t lead-free gasoline called E-10 Unleaded. 2. As a component of reformulated gasoline, both directly and/or as ethyl tertiary butyl ether (ETBE). 3. As a primary election fuel with 85 parts of ethanol blended with 15 parts of unleaded gasoline called E-85. (Rex Weber 2003) When mixed with unleaded gasoline, ethanol increases octane levels, decreases exhaust emissions, and increases the supply of gasoline. Ethanol in its liquid form, called ethyl alcohol, can be used as a fuel when blended with gasoline or in its authoritative state. Well the production of ethanol fuel began way back in1907 but Ethanol use and production has increased considerably during the 1980s and 1990s not just due to the lack of fossil fuels but was also due to several other factors 1.Ethanol reduces the countrys dependence on imported oil, cloggy the trade deficit and ensuring a dependable source of fuel should foreign supplies be interrupted. 2. Farmers see an increased demand for grain which helps to st abilize prices. 3. The quality of the environment improves. Carbon monoxide emissions are reduced, and lead and other carcinogens (cancer causing agents) are removed from gasoline. 5. 2Chemistry Glucose (a simple sugar) is created in the plant byphotosynthesis. 6 CO2+ 6 H2O + light C6H12O6+ 6 O2 Duringethanol fermentation,glucoseis decomposed into ethanol andcarbon dioxide.C6H12O6 2 C2H5OH+ 2 CO2+ heat During combustion ethanol reacts withoxygento produce carbon dioxide,water, and heat C2H5OH + 3 O2 2 CO2+ 3 H2O + heat After doubling the combustion reaction because two molecules of ethanol are produced for each glucose molecule, and adding all three reactions together, there are equal numbers of each type of atom on each side of the equation, and the net reaction for the overall production and consumption of ethanol is just Glucose itself is not the only substance in the plant that is fermented. The simple sugarfructosealso undergoes fermentation.Three other compounds in the plant can be fermented after breaking them up byhydrolysisinto the glucose or fructose molecules that compose them. Starchandcelluloseare molecules that are strings of glucose molecules, and sucrose(ordinary table sugar) is a molecule of glucose bonded to a molecule of fructose. The energy to create fructose in the plant ultimately comes from the metabolism of glucose created by photosynthesis, and so sunlight also provides the energy generated by the fermentation of these other molecules. Ethanol may also be produced industrially fromethene(ethylene).Addition of water to the double bond converts ethene to ethanol C2H4+ H2O CH3CH2OH This is done in the presence of an acid whichcatalyzesthe reaction, but is not consumed. The ethene is produced from petroleum bysteam cracking. 5. 3Production Ethanol can be produced by various methods but the most commonly used in todays world is by the method of fermentation and distillation of sugar whip, grains, corn and so on 5. 3. 1Ethanol from sugar cane The first stage in ethanol production is to grow a crop such as sugar cane. The sugar cane of cut down and undergoes fermentation and distillation. 5. 3. 2FermentationCrushed sugar cane in placed in fermentation tanks. Bacteria in the tanks acts on the sugar cane and in time produce a crude form of ethanol. This is then passed on to the distillation stills where it is refined to a pure form. 5. 3. 3Distillation The impure/crude ethanol is heated in a still until it vaporizes and rises into the neck where it cools and condenses back to pure liquid ethanol. The impurities are left behind in the still. The ethanol trickles down the condensing tubing into a barrel, ready for distribution. When burned it produces fewer pollutants than traditional fuels such as petrol and diesel.Fig. 6 Distillation process of impure/crude ethanol The production of petroleum is done by the fractional distillation of crude oil. 5. 3. 4Fractional Distillation The various components of crude oil have d ifferent sizes, weights and boiling temperatures so, the first step is to separate these components. Because they have different boiling temperatures, they can be separated easily by a process calledfractional distillation. The steps of fractional distillation are as follows 1. Youheatthe mixture of two or more substances (liquids) with different boiling points to a high temperature.Heating is usually done with high pressure steam to temperatures of about 1112 degrees Fahrenheit / 600 degrees Celsius. 2. The mixtureboils, forming vapor (gases) most substances go into the vapor phase. 3. Thevaporenters the bottom of a long column (fractional distillation column) that is change with trays or plates. The trays have many holes or bubble caps (like a loosened cap on a soda bottle) in them to allow the vapor to pass through. They increase the contact time between the vapor and the liquids in the column andhelp to collect liquids that form at various heights in the column.There is a tempe rature difference across the column (hot at the bottom, cool at the top). 4. Thevapor risesin the column. 5. As the vapor rises through the trays in the column, itcools. 6. When a substance in the vapor reaches a height where the temperature of the column is equal to that substances boiling point, it willcondenseto form a liquid. (The substance with the lowest boiling point will condense at the highest point in the column substances with higher boiling points will condense lower in the column. ). 7.The trayscollectthe various liquid fractions. 8. The salt away liquid fractions maypass to condensers, which cool them further, and then go to storage tanks, or they maygo to other areas for further chemical processing Fractional distillation is useful for separating a mixture of substances with narrow differences in boiling points, and is the most important step in the refining process. The oil refining process starts with a fractional distillation column. On the right, you can see seve ral chemical processors that are described in the next section.Very few of the components come out of the fractional distillation column ready for market. Many of them must be chemically processed to make other fractions. For example, only 40% of distilled crude oil is gasoline however, gasoline is one of the major products made by oil companies. Rather than continually distilling large quantities of crude oil, oil companies chemically process some other fractions from the distillation column to make gasoline this processing increases the yield of gasoline from each barrel of crude oil.Fig. 7 Fractional distillation of crude oil 5. 4Air pollution Compared with conventionalunleaded gasoline, ethanol is a particulate-free burning fuel source that combusts with oxygen to form carbon dioxide, water andaldehydes. Gasoline produces 2. 44CO2equivalentkg/l and ethanol 1. 94. Since ethanol contains 2/3 of the energy per volume as gasoline, ethanol produces 19% more CO2than gasoline for the same energy. TheClean Air Actrequires the addition ofoxygenatesto reduce carbon monoxide emissions in the United States.The additiveMTBEis currently being phased out due to ground water contamination hence ethanol becomes an attractive alternative additive. Annual Fuel Ethanol Production by Country (20072011)2646566 Top 10 countries/regional blocks (Millions of U. S. liquid gallons per year) World rank Country/Region 2011 2010 2009 2008 2007 1 United States 13,900 13,231 10,938 9,235 6,485 2 Brazil 5,573. 24 6,921. 54 6,577. 89 6,472. 2 5,019. 2 3 European Union 1,199. 31 1,176. 88 1,039. 52 733. 0 570. 30 4 China 554. 76 541. 55 541. 55 501. 90 486. 00 5 Thailand 435. 20 89. 80 79. 20 6 Canada 462. 3 356. 63 290. 59 237. 70 211. 30 7 India 91. 67 66. 00 52. 80 8 Colombia 83. 21 79. 30 74. 90 9 Australia 87. 2 66. 04 56. 80 26. 40 26. 40 10 Other 247. 27 Table 2 Annual fuel ethanol production by country Table 2 Annual fuel ethanol production by country World Total 22,35 6. 09 22,946. 87 19,534. 993 17,335. 20 13,101. 7 5. 5AdvantagesEthanol has a higher octane number (113) than regular unleaded gasoline (87) and premium unleaded gasoline (93). Complete combustion Ethanol molecules contain 35 percent oxygen, and serve as an oxygenate to raise the oxygen content of gasoline fuel. Thus, it helps gasoline burn completely and reduces the buildup of gummy deposits. Prevent overheating Ethanol burn cooler than gasoline. Fuel Type Ethanol Regular Gasoline Premier Gasoline E10 Gasohol E85 Gasohol Energy Content (/Gallons) 84,600 125,000 131,200 120,900 90,660 Table 3 Energy content of fuelsEnergy content As shown in Table 2, fuel ethanol contains around 33 percent less energy content than regular gasoline. The energy content of gasohol blends (E10 or E85) is determined by the energy content of ethanol and gasoline, and their ratio. Emissions from ethanol are about 48% of diesel it is lowest of any of the fuels. The clean burning characteristics extend turb ine life, possibly by as much as 100%. (K. K. Gupta 2010) 5. 6Disadvantages Loss of power and performance Pure ethanol is over 100+ octane, and provides the fuel with much of its octane rating.Because Ethanol burns at a lower temperature than the older (MTBE) gas, boaters can expect to see a 2 to 3 % drop in RPM. subprogram of ethanol in the pure state or as a blend would probably require replacement of any white metal or aluminum in the system as well as some elastomers. (K. K. Gupta 2010) 6. References Hydrogen diary Papers G. L. Juste (2006) Hydrogen injection as additional fuel in gas turbine combustor. Evaluation of effects. International Journal of Hydrogen Energy 31 (2006) 2112 2121 K. K. Gupta a,*, A. Rehman b, R. M.Sarviya b, (2010) Bio-fuels for the gas turbine A review. Renewable and Sustainable Energy Reviews 14 (2010) 29462955 P. A. Pilavachi (2000), Power generation with gas turbine systems and combined heat and power, Applied Thermal Engineering 20 (2000) 142114 29 Paolo Gobbato*, Massimo Masi, Andrea Toffolo, Andrea Lazzaretto (2010) Numerical simulation of a hydrogen fuelled gas turbine combustor. International Journal of Hydrogen Energy 36 (2011) 7993- 8002 Nils Erland L. Haugena, Christian Brunhuberb and Marie Bysveena (2012) Hydrogen fuel supply system and re-heat gas turbine.Combustion Energy Procedia 23 ( 2012 ) 151 160 Website Pyromex Technology Description http//www. pyromex. com/index. php/en/pyromex-technology/technology-description Methanol & Power alcohol A Special Report Burning Tomorrows Fuels, Power, S14-S15, February 1979. Test and Evaluation of Methanol in a Gas Turbine System, Southern California Edison Company, EPRI Report AP-1712, February 1981. Methanol. Clean Coal Stationary Engine Demonstration Project. Executive Summary, California Energy Commission, Report P500-86-004, February 1986. Methanol Power extension Demonstration Test Starts for a Power Source at Peak Demand Japanese High-Technology Monitor, 5 April 199 3. Ethanol blended fuels Rex Weber 2003 of Northwest Iowa union College in cooperation with the Iowa Corn Promotion Board. Fuel Ethanol Zhiyou Wen, Extension Engineer, biological System Engineering, Virginia Tech John Ignosh, Area Specialist, Northwest District, Virginia Cooperative Extension, Jactone Arogo, Extension Engineer, Biological System Engineering, Virginia Tech