Information AboutBiodiesel |
|
Biodiesel refers to , or an oxygenate, made from the oil and Methanol , but Alkane (non-oxygenate) biodiesel, that is, Biomass-to-liquid (BTL) fuel is also available. Sometimes even unrefined vegetable oil, or Straight Vegetable Oil , is incorrectly called "biodiesel". While straight vegetable oil can be used to run diesel engines, biodiesel has advantages in that it does not require fuel pre-heating and filtration due to issues with coagulation at colder temperatures (known as "waxing") and requires minimal or no modification to the fuel system. Alkane biodiesel is of a similar viscosity to petrochemical diesel, and is usually of a higher quality than petrochemical options available on the U.S. market. Biodiesels are Biodegradable and non- Toxic , and have significantly fewer emissions than Petroleum -based Diesel ( Petro -diesel) when burned. Biodiesel functions in current Diesel Engine s, and is a possible candidate to replace Fossil Fuel s as the world's primary transport energy source. With a Flash Point of 160 °C (320 °F), biodiesel is classified as a non- Flammable liquid by the Occupational Safety And Health Administration . This property makes biodiesel relatively safe to produce in your own home, and vehicles fueled by pure biodiesel are far safer in Accidents than ones powered by petroleum diesel or the explosively combustible Gasoline . Precautions should be taken in very cold climates, where biodiesel may gel at higher temperatures than petroleum diesel. Biodiesel can be distributed using today's Infrastructure , and its use and production is increasing rapidly (especially in Europe , the United States , and Asia ). Fuel stations are beginning to make biodiesel available to Consumer s, and a growing number of transport fleets use it as an additive in their fuel. Biodiesel is generally more expensive to purchase than petroleum diesel, but can be made at home for much cheaper than either. This differential may diminish due to Economies Of Scale , the rising cost of petroleum and government tax subsidies. HISTORY Transesterification of a Vegetable Oil was conducted as early as 1853, by scientists E. Duffy and J. Patrick , many years before the first Diesel Engine became functional. Rudolf Diesel 's prime model, a single 10 ft (3 m) iron cylinder with a flywheel at its base, ran on its own power for the first time in Augsburg , Germany on August 10 , 1893 . In remembrance of this event, August 10 has been declared International Biodiesel Day. Diesel later demonstrated his Engine and received the "Grand Prix" (highest prize) at the World Fair in Paris , France in 1900. This engine stood as an example of Diesel's vision because it was powered by Peanut oil—a Biofuel , though not strictly biodiesel, since it was not transesterified. He believed that the utilization of a biomass fuel was the real future of his engine. In a 1912 speech, Rudolf Diesel said "the use of vegetable oils for engine fuels may seem insignificant today, but such oils may become, in the course of time, as important as petroleum and the Coal-tar products of the present time." {Link without Title} During the 1920s diesel engine manufacturers altered their engines to utilize the lower Viscosity of the Fossil Fuel (petrodiesel) rather than vegetable oil, a Biomass Fuel . The petroleum industries were able to make inroads in fuel markets because their fuel was much cheaper to produce than the Biomass alternatives. The result was, for many years, a near elimination of the biomass fuel production infrastructure. Only recently have environmental impact concerns and a decreasing cost differential made biomass fuels such as biodiesel a growing alternative. The revival of biodiesel production started with farm co-operatives in the 1980s in Austria , but in 1991 the first industrial-scale plant opened in Aschach , also in Austria , with a capacity in excess of 10,000 m³ per year. Throughout the 1990s, plants were opened in many European countries, including the Czech Republic , France , Germany , Sweden . At the same time, nations in other parts of world also saw local production of biodiesel starting up and by 1998, the Austrian Biofuels institute identified 21 countries with commercial biodiesel projects. In the 1990s, France launched the local production of biodiesel fuel (known locally as diester) obtained by the transesterification of Rapeseed oil. It is mixed to the proportion of 5 % into regular Diesel Fuel , and to the proportion of 30 % into the diesel fuel used by some captive fleets ( Public Transportation ). Renault , Peugeot , and other manufacturers have certified truck engines for use with up to this partial biodiesel. Experiments with 50 % biodiesel are underway. From 1978 to 1996, the U.S. National Renewable Energy Laboratory experimented with using Algae as a biodiesel source in the " Aquatic Species Program ". A recent paper from Michael Briggs at the UNH Biodiesel Group, offers estimates for the realistic replacement of all vehicular fuel with biodiesel by utilizing algae that has a greater than 50 % natural oil content, which he suggests can be grown on algae ponds at wastewater treatment plants. Meanwhile, independent results have shown that GreenFuel Technologies, a Cambridge, MA company founded by and 86% less Nitrous Oxide . This oil-rich Algae can then be extracted from the system and processed into biodiesel, and the dried remainder further reprocessed to create ethanol. The company is testing their method at the MIT cogeneration facility and at an undisclosed 1000-megawatt power facility in the southwestern U.S. FUEL QUALITY, STANDARDS AND PROPERTIES Biodiesel is a transparent amber-yellow liquid with a Viscosity similar to Petrodiesel , the industry term for diesel produced from Petroleum . It can be used as an additive in formulations of diesel to increase the Lubricity of pure Ultra-low Sulfur Petrodiesel (ULSD) fuel. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix, in contrast to the "BA" system used for Bioalcohol mixes. For example, fuel containing 20 % biodiesel is labeled B20. Pure biodiesel is referred to as B100. The common international standard for biodiesel is EN 14214. There are additional national specifications. The standard ASTM D 6751, which is the most common standard referenced in the United States. In Germany, the requirements for biodiesels are fixed in the DIN EN 14214 standard. There are standards for three different varieties of biodiesel, which are made of different oils:
The standards ensure that the following important factors in the fuel production process are satisfied:
Basic industrial tests to determine whether the products conform to the standards typically include Gas Chromatography , a test that verifies only the more important of the variables above. More complete testings are more expensive. Fuel meeting the quality standards is very non-toxic, with a toxicity rating ( LD50 ) of greater than 50 mL/kg. Biodiesel can be mixed with petroleum diesel at any concentration in most modern engines, although it has the disadvantage of degrading Rubber Gasket s and Hose s in vehicles manufactured before 1992. Biodiesel is a better Solvent than petrodiesel and has been known to break down deposits of residue in the fuel lines of vehicles that have previously been run on petroleum. Fuel filters may become clogged with particulates if a quick transition to pure biodiesel is made, but biodiesel cleans the engine in the process. It is therefore recommended, to change the fuel filter 800 miles after switching to biodiesel. In a study at a U.S. military base, a biodiesel blend was used as a replacement for heating oil at housing on the base. Due to the good solvating ability of biodiesel, residues that had been present in fuel tanks for decades were dissolved. The particulate component of the residues caused repeated clogging of fuel strainers, requiring repeated replacement, cleaning, and in some cases installation of higher capacity filters. Due to the relatively smaller surface area and service life of fuel tanks in motor vehicles and mobile equipment, filter clogging is less prevalent but still a factor to be considered. Two real-world issues involving the use of biodiesel There are a number of different feed stocks ( Methyl Esters , refined Canola Oil , French Fry oil, etc.) that are used to produce biodiesel or vegidiesel (vegifuel), but in the end they all have a few common problems. First, any of the biodiesel products have a problem of gelling when the temperatures get below 4.4 °C (40 °F) or so, depending on the mix of esters. At the present time there is no available product that will significantly lower the gel point of straight biodiesel. A number of studies have concluded that winter operations require a blend of bio, #2 low . The second problem with biodiesel is that it is Hydrophilic . Some of the water present is residual to processing, and some comes from storage tank Condensation . The presence of water in biodiesel is a problem for a number of reasons:
Environmental benefits Environmental benefits in comparison to petroleum based fuels include:
Since biodiesel is more often used in a blend with petroleum diesel, there are fewer formal studies about the effects on pure biodiesel in unmodified engines and vehicles in day-to-day use. Fuel meeting the standards and engine parts that can withstand the greater solvent properties of biodiesel is expected to--and in reported cases does--run without any additional problems than the use of petroleum diesel. The flash point of biodiesel (>150 °C) is significantly higher than that of petroleum diesel (64 °C) or gasoline (−45 °C). The gel point of biodiesel varies depending on the proportion of different types of esters contained. However, most biodiesel, including that made from soybean oil, has a somewhat higher gel and cloud point than petroleum diesel. In practice this often requires the heating of storage tanks, especially in cooler climates. Pure biodiesel (B100) can be used in any petroleum Diesel Engine , though it is more commonly used in lower concentrations. Some areas have mandated ultra-low sulfur petrodiesel, which reduces the natural viscosity and lubricity of the fuel due to the removal of sulfur and certain other materials. Additives are required to make ULSD properly flow in engines, making biodiesel one popular alternative. Ranges as low as 2 % (B2) have been shown to restore lubricity. Many municipalities have started using 5 % biodiesel (B5) in snow-removal equipment and other systems.
PRODUCTION ''Main article:'' Biodiesel Production Chemically, biodiesel comprises a mix of mono- Alkyl Ester s of long chain Fatty Acid s. The most common form uses Methanol to produce Methyl esters as it is the cheapest alcohol available, though Ethanol can be used to produce an ethyl ester biodiesel and higher alcohols such as isopropanol and butanol have also been used. Using alcohols of higher molecular weights improves the cold flow properties of the resulting ester, at the cost of a less efficient transesterification reaction. A byproduct of the transesterification process is the production of Glycerol . A Lipid Transesterification production process is used to convert the base oil to the desired esters. Any Free Fatty Acid s (FFAs) in the base oil are either converted to soap and removed from the process, or they are esterified (yielding more biodiesel) using an acidic catalyst. After this processing, unlike Straight Vegetable Oil , biodiesel has Combustion properties very similar to those of petroleum diesel, and can replace it in most current uses. Base oils s are used as a source of biodiesel]] A variety of Biolipid s can be used to produce biodiesel. These include:
Worldwide production of vegetable oil and animal fat is not yet sufficient to replace liquid fossil fuel use. Furthermore, some environmental groups object to the vast amount of Farming and the resulting over- Fertilization , Pesticide use, and land use conversion that would be needed to produce the additional vegetable oil. Many advocates suggest that waste vegetable oil is the best source of oil to produce biodiesel. However, the available supply is drastically less than the amount of petroleum-based fuel that is burned for transportation and home heating in the world. According to the United States Environmental Protection Agency (EPA), restaurants in the US produce about 300 million US gallons (1,000,000 m³) of waste cooking oil annually. Although it is economically profitable to use WVO to produce biodiesel, it is even more profitable to convert WVO into other products such as Soap . Hence, most WVO that is not dumped into Landfill s is used for these other purposes. Animal fats are similarly limited in supply, and it would not be efficient to raise animals simply for their fat. However, producing biodiesel with animal fat that would have otherwise been discarded could replace a small percentage of petroleum diesel usage. The estimated transportation fuel and home heating oil used in the United States is about 230,000 million US gallons (0.87 km³) (Briggs, 2004). Waste vegetable oil and animal fats would not be enough to meet this demand. In the United States, estimated production of vegetable oil for all uses is about 23,600 million pounds (10,700,000 t) or 3,000 million US gallons (11,000,000 m³)), and estimated production of animal fat is 11,638 million pounds (5,279,000 t). (Van Gerpen, 2004) For a truly renewable source of oil, crops or other similar cultivatable sources would have to be considered. Plants utilize Photosynthesis to convert solar energy into chemical energy. It is this chemical energy that biodiesel stores and is released when it is burned. Therefore plants can offer a sustainable oil source for biodiesel production. Different plants produce usable oil at different rates. Some studies have shown the following annual production:
There is ongoing research into finding more suitable crops and improving oil yield. Using the current yields, vast amounts of land and fresh water would be needed to produce enough oil to completely replace fossil fuel usage. It would require twice the land area of the US to be devoted to soybean production, or two-thirds to be devoted to rapeseed production, to meet current US heating and transportation needs. Soybeans are not a very efficient crop solely for the production of biodiesel, but their common use in the United States for food products has led to soybean biodiesel becoming the primary source for biodiesel in that country. Soybean producers have lobbied to increase awareness of soybean biodiesel, expanding the market for their product. In Europe, rapeseed is the most common base oil used in biodiesel production. In India and southeast Asia, the Jatropha tree is used as a significant fuel source, and it is also planted for Watershed protection and other environmental restoration efforts. In Asia, the first country to launch biodiesel as a national program was Thailand when a national policy was announced on July 10th 2001. It was reported that the work was initiated by the Royal Chitralada Project, a royal -sponsored project to help rural farmers (www.royalchitralada.or.th). Progress has been made on several fronts, details available at www.ethanol-thailand.com, www.dede.go.th, www.navy.mi.th/dockyard/biodiesel.html). International co-operation among ASEAN country was also starting by the Renewablle Energy Inst of Thailand (Dr.Samai Jai-In) and Asia-Pacific Roundtable for Sustainable consumption and Production (Dr.Olivia Castillo, http://www.aprscp.org/news/chaircorner.htm). Malaysia and Indonesia are starting pilot-scale production from palm oil, but these projects have been criticized by some environmental advocates. Friends Of The Earth has published a report asserting that clearance of forests for oil-palm plantations is threatening some of the last habitat of the Orangutan . Also, in a column for The Guardian , writer George Monbiot claimed that land clearance by cutting and burning large forest trees frees large amounts of Carbon Dioxide that is never reabsorbed by the smaller oil palms. If true, then biodiesel production from plantation-grown palm oil may be a net source of atmospheric carbon dioxide. Specially bred mustard varieties can produce reasonably high oil yields, and have the added benefit that the meal leftover after the oil has been pressed out can act as an effective and biodegradable Pesticide . The production of Algae to harvest oil for biodiesel has not been undertaken on a commercial scale, but working feasibility studies have been conducted to arrive at the above yield estimate. In addition to a high yield, this solution does not compete with agriculture for food, requiring neither farmland nor fresh water. Efficiency and economic arguments According to a study written by Drs. Van Dyne and Raymer for the combined with an electric drive train. Biodiesel outcompetes solar cells in cost and ease of deployment. However, these statistics by themselves are not enough to show whether such a change makes economic sense. Additional factors must be taken into account, such as: the fuel equivalent of the energy required for processing, the yield of fuel from raw oil, the return on cultivating food, and the relative cost of biodiesel versus petrodiesel. A 1998 joint study by the U.S. Department Of Energy (DOE) and the U.S. Department Of Agriculture (USDA) traced many of the various costs involved in the production of biodiesel and found that overall, it yields 3.2 units of fuel product energy for every unit of fossil fuel energy consumed. That measure is referred to as the Energy Yield . A comparison to petroleum diesel, petroleum gasoline and Bioethanol using the USDA numbers can be found at the Minnesota Department of Agriculture website In the comparison petroleum diesel fuel is found to have a 0.843 energy yield, along with 0.805 for petroleum gasoline, and 1.34 for bioethanol. The 1998 study used soybean oil primarily as the base oil to calculate the energy yields. It is conceivable that higher oil yielding crops could increase the energy yield of biodiesel. The debate over the energy balance of biodiesel is ongoing, however. Some nations and regions that have pondered transitioning fully to biofuels have found that doing so would require immense tracts of land if traditional crops are used. Considering only traditional plants and analyzing the amount of biodiesel that can be produced per unit area of cultivated land, some have concluded that it is likely that the United States , with one of the highest Per Capita energy demands of any country, does not have enough Arable Land to fuel all of the nation's vehicles. Other developed and developing nations may be in better situations, although many regions cannot afford to divert land away from food production. For Third World countries, biodiesel sources that use marginal land could make more sense, e.g. honge nuts grown along roads. More recent studies using a species of Algae that has oil contents of as high as 50% have concluded that as little as 28,000 km&2 or 0.3 % of the land area of the US could be utilized to produce enough biodiesel to replace all transportation fuel the country currently utilizes. Further encouragement comes from the fact that the land that could be most effective in growing the algae is desert land with high solar irradiation, but lower economic value for other uses and that the algae could utilize farm waste and excess CO2 from factories to help speed the growth of the algae. The direct source of the energy content of biodiesel is solar energy captured by plants during Photosynthesis . The website biodiesel.co.ukdiscusses the positive energy balance of biodiesel: :When straw was left in the field, biodiesel production was strongly energy positive, yielding 1 GJ biodiesel for every 0.561 GJ of energy input (a yield/cost ratio of 1.78). :When straw was burned as fuel and oilseed rapemeal was used as a fertilizer, the yield/cost ratio for biodiesel production was even better (3.71). In other words, for every unit of energy input to produce biodiesel, the output was 3.71 units (the difference of 2.71 units would be from solar energy). Biodiesel is becoming of interest to companies interested in commercial scale production as well as the more usual home brew biodiesel user and the user of Straight Vegetable Oil or waste vegetable oil in diesel engines. Homemade Biodiesel Processor s are many and varied. AVAILABILITY SEE ALSO
REFERENCES
Notes |
|
|