How to Convert Vegetables into Usable Fuels for Autos - Essay Example

Michael Lenser Miller Chemistry 104 July 20, 2007 How to convert vegetables into usable fuels for autos Transportation accounts for more than 67 percent of the oil consumed in the United States which is more than the production. Today, United States imports more than 54 percent of its oil supply, and it's estimated that this could increase to 75 percent by 2010. According to the U.S. Federal Highway Administration, the average vehicle (car or light truck) on the road today emits more than 600 pounds of air pollution each year (Durbin et al, 2000). These pollutants (such as carbon monoxide, sulfur dioxide, nitrogen dioxide, and particulate matter) contribute to smog and too many health problems. For example, smog can cause eye and respiratory tract irritation, and carbon monoxide can inhibit the ability of a person's blood to carry oxygen to vital organs. The average vehicle, through its combustion of fossil fuels, also emits greenhouse gases. Greenhouse gases, such as carbon dioxide, methane, nitrous oxide, hydrocarbons, and chlorofluorocarbons surround the Earth's atmosphere like a clear thermal blanket, allowing the sun's warming rays in and trapping the heat close to the Earth's surface. This natural greenhouse effect keeps the average surface temperature at around 60F (33C). However, the increased use of fossil fuels during the last century has created an enhanced greenhouse effect, known as global warming. And transportation has played a large role in this increase. During the 1990s, the annual growth rate of U.S. greenhouse gas emissions from transportation averaged 1.6 percent. In 1999, some 82 percent of U.S. greenhouse gas emissions consisted of carbon dioxide released by the combustion of energy fuels. The U.S. Environmental Protection Agency (EPA) estimates (Durbin et al, 2000) that each year the average light vehicle in the United States releases 10,000 pounds of carbon dioxide into the air. Motor gasoline contributed close to 300 million metric tons of carbon dioxide, making it the largest single source of U.S. carbon dioxide emissions. By reducing vehicle emissions, AFVs and advanced vehicle technologies help combat both air pollution and global climate change. Alternative fuels not only burn cleaner producing lower emissions, but some are even renewable, unlike fossil fuels, which means we could develop a continuous supply of them. The alternative fuels in use today include ethanol, biodiesel, methanol, natural gas, propane, electricity, and hydrogen. Biofuels are renewable since they are produced from biomass i.e. organic matter, such as plants. They generate about the same amount of carbon dioxide (a greenhouse gas) from the tailpipe as fossil fuels, but the plants that are grown to produce the biofuels actually remove carbon dioxide from the atmosphere (ERCL, 1999). Therefore, the net emission of carbon dioxide will be close to zero. Diesel engines can function efficiently with biodiesel, a fuel made from vegetable oil. A combination of vegetable oil and diesel fuel produce fewer emissions than straight diesel. Commercially available biodiesel is offered in blends of 5% vegetable oil to 95% diesel (B5), 10% to 90% (B10) and 20% to 80% (B20). Consumers can have their diesel engines converted for around 800 dollars-to run on 100% vegetable oil (Anthony & Cornish, 2001). The oil produces no harmful emissions and the cost can be nominal or free since many consumers get used vegetable oil from fast food restaurants, but consumers must filter their used oil, which is complicated and the equipment is costly. In addition, buying pure vegetable oil can cost more than straight diesel fuel. Fuel consumption for vegetable oil is similar to diesel, which gets 20 to 30 percent better mileage than gasoline (ERCL, 1999). Emissions are much less toxic than those from gasoline, and its carbon neutral because the carbon dioxide absorbed by the plant from which the oil is derived offsets CO2 generated when it is used as fuel. With the increasing popularity of vegetable oil as a motor fuel, a small industry of conversion kit installers has grown up, and some also supply the oil for their customers. Walton (1938) recommended that "to get the utmost value from vegetable oils as fuel it is academically necessary to split off the triglycerides and to run on the residual fatty acid. Practical experiments have not yet been carried out with this; the problems are likely to be much more difficult when using free fatty acids than when using the oils straight from the crushing mill. It is obvious that the glycerides have no fuel value and in addition are likely, if anything, to cause an excess of carbon in comparison with gas oil." Although Walton's statement points in the direction of what is now termed biodiesel by recommending the elimination of glycerol from the fuel, some remarkable work performed in Belgium and its former colony the Belgian Congo (known after its independence for a long time as Zaire) deserves more recognition than it has received. The kinematic viscosity of vegetable oils is about an order of magnitude greater than that of conventional, petroleum-derived diesel fuel. High viscosity causes poor atomization of the fuel in the engine's combustion chambers and ultimately results in operational problems, such as engine deposits. Since the renewal of interest during the late 1970s in vegetable oil-derived fuels, four possible solutions to the problem of high viscosity have been investigated: transesterification, pyrolysis, dilution with conventional petroleum-derived diesel fuel, and microemulsification (Bruwer et al, 1980). Transesterification is the most common method and leads to monoalkyl esters of vegetable oils and fats, now called biodiesel when used for fuel purposes. Briefly, it consists of reacting the vegetable oil feedstock with an alcohol, usually methanol, in the presence of a catalyst, usually a base such as sodium or potassium hydroxide, to give the corresponding The high viscosity of vegetable oils as a major cause of poor fuel atomization resulting in operational problems such as engine deposits was recognized early. Although engine modifications such as higher injection pressure were considered, reduction of the high viscosity of vegetable oils usually was achieved by heating the vegetable oil fuel (Mansson, 1997). Often the engine was started on petrodiesel and, after a few minutes of operation, was then switched to the vegetable oil fuel, although a successful cold-start on high-acidity peanut oil was reported (Mansson, 1997). Advanced injection timing was a technique also employed. Biodiesel is produced by chemically reacting alcohol with vegetable oils, fats, or greases. Metal carbonate and other chemical catalysts facilitate the conversion process. Biodiesel production involves the esterification of fats and oils. Esterification is the chemical preparation of methyl esters of fatty acids from triglycerides. Fat/Oil is mixed with methyl alcohol and catalyst (NaOH) Circulation and mixing help reaction proceed to completion, generally with around 95% conversion to methyl esters (Buckmann & Malsen, 1997). Pyrolysis is a process used in producing biodiesel. It involves the slow irreversible thermal degradation of organic composites in biomass, mostly lignocellulosic polymers, in the absence or near absence of oxygen to make products like charcoal. An off-the-grid method test model of converting vegetables into usable fuel for autos would be as follows (Mann, 1998). Vegetables cannot be directly converted into auto fuel. Rather they have to be in the form of vegetable oil to get converted. Initially an 85 gallon processing tank would be required to convert vegetable oil into the clean-burning, alternative fuel known as biodiesel. Using discarded materials from old bicycles, a pedal mechanism should be constructed that is attached by way of an intricate set of chains and gears to the blade inside the processing tank. Then the concoction has to be mixed inside the vat into a usable fuel source. The process of converting vegetable into something that can power a diesel engine requires vegetable oil in a large quantity. The oil has to be strained to remove remnants of food. Using waste oil closes a recycling loop in the community. By taking something that has been used and turning it into something that can be used again, wastage of resources could be avoided. Once the oil is strained, it has to be heated with a Babington burner. Meanwhile, a mixture of methanol and lye has to be placed into the processing tank, and mixed for approximately 15 minutes. Once the oil heats to 135 degrees, it's pumped into the processing tank. The processor has to be pedaled which in turn would catalyze the chemical reaction that converts the oil into biodiesel. Once the pedaling is done, the mixture has to be left to settle. Approximately eight hours later, the transformation would be complete. Biodiesel doesn't release sulfur oxides into the air, and it cuts down on the particulate matter released by diesel engines. Crude Palm Oil and Refined Palm Oil are the most traded vegetable oil in the world today. Palm oils have been as a dietary nutrient for nearly five thousand years. Palm oil is harvested from the mesocarp of the Elaeis guineensis fruit, through a refining process that includes; cooking, mashing and pressing. In this process, the seeds are separated and after cracking and removing the shell, the kernel can be processed to yield palm kernel oil and palm kernel cake (Ceuterick & Spirinckx, 1999). Palm trees are "unisexual" in that they have male and female flowers within the tree. The female flowers bears fruit known as "fresh fruit bunches" or "FFB." Each palm tree is capable of bearing about 10 to 12 bunches per year. Each FFB averages 1000 to 3000 fruits with weights varying between 40 to 70 pounds (Mittelbach, 1998). Crude palm oil - also referred to as "CPO" comes from the mesocarp (the fleshy portion of the fruit wall) and depending on the variety and age of the palm. The CPO to bunch ratio is about 25 to 28 percent (Mittelbach, 1998). After crude palm oil is refined, it is then referred to as Refined Palm Oil, and can then be used in a number of applications, including as a substitute for petroleum diesel which is known as Palm Oil Biodiesel. Additionally, Palm Oil Biodiesel can be blended with petroleum diesel. Canola biodiesel is an environmentally- friendly, renewable energy source that could also produce cost savings for taxpayers and private businesses and is produced from farmers that grow canola.Biodiesel produced from canola and rapeseed oil is superior to soy biodiesel, especially due to the widely varying price fluctuations of soybeans. And because the feedstock (the oil produced from the fuel crop, such as soybeans, rapeseed or canola) to make biodiesel makes up about 80% of the cost for100 % biodiesel, basic economics dictate that the feedstock be obtained from the least-cost source, which is going to be either canola or rapeseed (Sheehan et al, 1998).Initial research conducted by the University of Saskatchewan and the AAFC Saskatoon Research Centre has found that each ton of renewable biodiesel fuel saves five times its weight in diesel fuel. As well, engines using biodiesel demonstrate wear rates as much as 50% lower than those using regular commercial fuels effectively doubling engine life (Sheehan et al, 1998). Canola is a member of the Brassica Family, which includes broccoli, cabbage, cauliflower, mustard, radish, and turnip. It is a variant of the crop rapeseed. Grown for its seed, the seed is crushed for the oil contained within. After the oil is extracted, the by-product is a protein rich meal used by the intensive livestock industry.Canola is a very small seed, which means sowing depth must be controlled. The current sowing practice is to cover the seed lightly with soil, which provides more protection from drying out after germination. Canola is generally sown in autumn and develops over winter, with flowers emerging in the spring and is harvested early summer. With a growing period of around 180-200 days climatic effects such as sudden heat waves can reduce yields and hot dry conditions can limit its oil content. Summer weather ensures low moisture (less than 6%) at harvest. Carry-in stocks of canola are minimal because of a lack of on-farm storage. Canola is a good rotational crop, acting as a break crop for cereal root diseases. However for disease-related reasons, a rotation period of 3-5 years is required for canola crops of iodine in grams absorbed per 100 ml of oil is then the IV (Wang et al, 2000). The higher the IV, the more unsaturated (the greater the number of double bonds available) is the oil and the higher the potential to 'gum up' when used as a fuel in an engine. Though some oils have a low IV and are suitable without any further processing other than extraction and filtering, the majority of vegetable and animal oils have an IV which does not permit their use as a neat fuel.Generally speaking, an IV of less than about 25 is required if the neat oil is to be used in unmodified diesel engines and this severely limited the types of oil that can be used. The IV can be easily reduced by hydrogenation of the oil (reacting the oil with hydrogen), the hydrogen breaking the double bond and converting the fat or oil into a more saturated oil and reducing the tendency of the oil to polymerize (Wang et al, 2000). However this process also tends to increase the melting point of the oil and converts the oil into margarine. Only coconut oil has an IV low enough to be used without any special precautions in an unmodified diesel engine. However with a melting point of 25C, the use of coconut oil in cooler areas would obviously lead to problems. Linseed oil could be mixed with petroleum diesel at a ratio of up to 1:8 to give an equivalent IV in the mid-twenties. Likewise coconut oil can be thinned with diesel or kerosene to render it less viscous in cooler climates. Obviously the solubility of the oil in petroleum also needs to be taken into account. Another method is to emulsify the oil or fat with ethanol. Most vegetable oils are a mixture of different esters such as oleic acid (main constituent of olive oil), ricinoleic acid (main constituent of castor oil), linoleic acid (main constituents of linseed oil), and palmitic acid (main constituent of palm kernel oil) and so on (Watson & Alimoradian, 2000). In an analogous way to that in which crude oil is refined to make a useable automotive fuel, canola oil needs to be transesterified to make an automotive fuel that is useable in unmodified diesel engines.When the oil is processed in a transesterfication process, the various fatty acids react with the alcohol to form a mixture of lighter esters and glycerol. The name of the specific fuel is called after the plant (or animal) source plus the alcohol. Made from rapeseed oil and methanol, the biodiesel is called Rape Methyl Ester (RME), from canola oil and ethanol, and from Canola Ethyl Ester (CEE) (Watson & Alimoradian, 2000). Rapeseed, some varieties of which are used to make mustard and others to make canola oil, is the preferred biodiesel feedstock in Europe. Depending on the variety, rapeseed oil contains about 40 to 50 percent of its weight in rapeseed is oil, as compared with only 20 percent for soybeans (Watson & Alimoradian, 2000). It can be planted and harvested with the same equipment used for small grains. In addition, rapeseed oil offers certain advantages in the production of biodiesel. Conclusion To conclude alternative fuel type is important for the future. Alternative fuels are going to be how our children, and grandchildren will get around, function and in many cases will be what will determine how polluted the air is, and how the overall health of the world is being handled. The alternative fuels types of the future is going to be based on renewable sources, man made sources, and this will not be based on oils, gas, or on the fossil fuels that are created and stored deep within the earth. The fuel sources we do have, such as natural gasses, oils, diesel, and the coal that is burned in the many types of furnaces are going to run out at some point. When these natural resources run out, we have to be ready and able to continue with life, as we know it with alternative fuel sources. There are many types of alternative fuel types that are currently being investigated. Some of the fuel sources that are already being used in our society include the use of electricity, the use of hydrogen and the use of biodeisel among others. It is surprising that soybean oils, corn oils, vegetables oils, garbage, manure and even solar power are all considerations for the many types of alternative fuels that are needed to satisfy the needs of so many people around the world. The world needs to continue to focus on the need for alternative fuels so that we will be ready and prepared with great resources when the natural resources of the world run out. References Anthony, L. & S. Cornish. 2001. ATA's Biodiesel Project Background on biodiesel, Alternative Technology Association 2001, pp.89-90. Buckmann, M. & Malsen. 1997. Biodiesel: a climate-friendly auto fuel Greenhouse Issues, p.31. Bruwer, J.J., Boshoff, Hugo, Plessis, Fuls, Hawkins, Walt & Engelbrecht. 1980. Sunflower Seed Oil as an Extender for Diesel Fuel in Agricultural Tractors, Symposium of the South African Institute of Agricultural Engineers, p.105-110. Ceuterick, D. & Spirinckx. 1999. Comparative LCA of Biodiesel and Fossil Diesel Fuel, VITO (Vlaamse Instelling voor Technologsich Onderzoek), Mol, Belgium, p.73. Durbin, T.D., Collins, J.R., Norbeck, J.M. and Smith, M.R. 2000. Effects of biodiesel, biodiesel blends, and a synthetic diesel on emissions from light heavy-duty diesel vehicles. Environmental Science and Technology, 34 (3): 349-355. Ecotec Research and Consulting Ltd. 1999. Financial and Environmental Impact of Biodiesel as an Alternative to Fossil Diesel in the UK, Report for the British Association for Bio Fuels and Oils (BABFO), Spalding Lincolnshire, p.20. Mann, P. 1998. The production and use of ethyl esters from vegetable oils. International Liquids Biofuels Congress proceedings, Jefferson City, MO: National Biodiesel Board, pp.25-30. Mansson, T. 1997. Bio-based fuels for buses, Lorries and Cars. CADDET Energy Efficiency Newsletter, (3): 4-6. Mittelbach, M. 1998. The Importance of Diesel Fuel Substitutes from Non-Edible Seed Oils. International Liquids Biofuels Congress proceedings, Brazil, Jefferson City, MO: National Biodiesel Board, p.96. Sheehan, J., Camobreco, Duffield, Graboski & Shapouri. 1998. Lifecycle inventory of biodiesel and petroleum diesel for use in an urban bus. (Report; NREL/SR-580-24089) Golden, CO: National Renewable Energy Laboratory. Xxiv, p.284. Walton, J. 1938. The Fuel Possibilities of Vegetable Oils, Gas Oil Power, 33:167-168. Wang, W.G., Lyons, Clark, Gautam, & Norton. 2000. Emissions from nine heavy trucks fuelled by diesel and biodiesel blend without engine modification, Environmental Science and Technology, 34, 933- 939. Watson, H.C. & Alimoradian, B. 1989. A transient engine mapping model for analyzing and predicting fuel consumption and emissions. European Automobile Engineers Committee, 2nd Intl Conf. on New Developments in Powertrain and Chassis Engineering, Strasbourg, pp.27-36. Read More