Soy biodiesel

The production of methyl soyate for environmentally friendly solvents and for biodiesel fuel (in the USA) is becoming a significant outlet for soy oil in non-food applications. Further progress in the demand for soy biodiesel will result in additional soybean meal supphes, which will considerably increase soy meal competitiveness as feedstock for hvestock farming and aquaculture. 

Mueller CJ, Boehman AL, Martin GC. An experimental investigation of the origin of increased NO emissions when fueling a heavy-duty compression-ignition engine with soy biodiesel. SAE Int J Fuels Lubr. 2009 2 789-816. 

Biodiesel is diesel fuel produced from vegetable oils and other renewable resources. Many different types of oils can he used, including animal fats, used cooking oils, and soybean oil. Biodiesel is miscible with petroleum diesels and can he used in biodiesel-diesel blends. Most often blends are 20 percent biodiesel and 80 percent traditional diesel. Soy diesel can be used neat (100%), hut many other types of biodiesel are too viscous, especially in winter, and must be used in blends to remain fluid. The properties of the fuel will vaiy depending on the raw material used. Typical values for biodiesel are shown in Table 1. 

By 2006, the U.S. had 77 ethanol plants producing more than 3 billion gallons of ethanol per year. Canada produced an additional 60 million gallons. Corn was the feedstock in 62 of the 77 U.S. plants. Other feedstocks included seed corn, corn and barley, corn and beverage waste, brewery waste, cheese whey, corn and milo, corn and wheat starch, potato waste and various sugars. The U.S. had 11 additional plants under construction and 55 proposed. West Central Soy processes soybeans to a food grade oil. Alcohol and a catalyst are then used to produce biodiesel fuel and glycerin. 

Biodiesel (fatty acid methyl ester (FAME)) production is based on transesterification of vegetable oils and fats through the addition of methanol (or other alcohols) and a catalyst, giving glycerol as a by-product (which can be used for cosmetics, medicines and food). Oil-seed crops include rapeseeds, sunflower seeds, soy beans and palm oil seeds, from which the oil is extracted chemically or mechanically. Biodiesel can be used in 5%-20% blends with conventional diesel, or even in pure form, which requires slight modifications in the vehicle. 

Biodiesel can be produced from various oilseed-yielding plants like castor, cotton, jatropha, palm, rape, soy, etc. The straight vegetable oils (SVO), which can be derived by physical and chemical treatment (milling/refining), are then converted into fatty acid methyl esters (FAME), also known as biodiesel. Similar to ethanol, these routes are established and proven, and their costs depend heavily on two factors ... 

Another route for biodiesel is to hydrotreat unprocessed bio-oils (from castor, cotton, palm, soy etc.) so that no transesterification is needed to stabilize the biodiesel. 

It is clear that an accurate prediction of the CP, PP, or CFPP is almost impossible, certainly since presence of crystallizable minor components can have a significant effect. Some of these components, such as phytosterol glycoside esters in soy-based FAME, can speed nucleation and crystallization other molecules creating steric hindrance in the growing nucleus will retard crystallization. Such components are often added to biodiesel to reduce the size of crystals or inhibit crystal formation by preventing nucleation. 

The more pragmatic approach used in the Biodiesel Cost Optimizer (see below) is based on the work of Dr. Lee and colleagues (1996). Soy methyl esters were winterized on lab scale at -21.5°C, -25.0 °C and -28.4 °C. This yielded FAME olein with 11.2%, 7.4% respectively 6.0% saturated FAME (palmitic acid and stearic acid methyl esters), and FAME stearin with 46.6%, 42.2% respectively 33.1% saturated FAME. This simple lab test con-... 

Table 3.2 displays some examples for ternary blends of palm oil, soybean oil and rapeseed oil methyl esters. Under the price conditions given in the table, a typical winter formula would contain SQ-90% rapeseed methyl esters, with the balance mainly soy methyl esters and maybe a few percent of palm methyl esters. In summertime no rapeseed would be used. For Europe 70 to 80% soy methyl esters would combine with palm methyl esters as the balance. For Biodiesel in the U. S., the palm oil methyl ester content would be equally high, making the formula considerably cheaper than pure soy methyl esters. 

Soybean, com and sunflower oil content can also be manipulated by plant breeding (47, 48). Historic attempts to increase oil content of soy have lowered protein production (47). If the domestic demand for soybean biodiesel increases in North America, diversion of plant photosynthate from meal to oil production may prove advantageous and limit market distortions. 

Currently, most biodiesel is synthesized from higher quality vegetable oils, including canola, sunflower, and soy. More recently, used frying oil and tallow have... 

The early stages of most biodiesel reactions proceed slowly, but the slow reaction is readily overcome when the reaction is induced to form a single phase. Boocock (87) described methods of accelerating methyl ester synthesis by adding ether cosolvents. In one example, 100 g of soy oil was reacted with 28 mL of methanol in the presence of 35 mL of tetrahydrofuran and 1 g of sodium hydroxide. The reaction proceeded rapidly and separated in 20 min. After the reaction was complete, the solvents were flashed off the methyl ester phase and a small amount of glycerol separated. The ester yield was 90.1%. 

Vegetable oils fijom crops, with a total lipid content of at least 20% by weight, such as soy bean, rape seed and sunflower, have been studied and cultivated in plantations as sources of feed stock for biodiesel production in the USA and in European countries such as France, Austria and Italy. For Kenya and Afiica at large, where there is a dire need for food, the use of such edible oil crops for fuel would be ridiculous. Jatropha curcas (family Euphorbiaceae), which constitutes 53-57% non-edible oils, has therefore been evaluated as a source of oil for biodiesel production. 

Opportunities may be available to use the method as the front-end to a soybean biorefinery to produce oil for biodiesel, ethanol from soy fiber (cell walls), and value-added protein products, and to integrate into small-scale, organic and identity-preserved processing strategies. In this approach (Fig. 11.20), several new steps were incorporated including step of flaking and twin-screw extruding to achieve more... 

The specification for biodiesel, ASTM D 6751 (ASTM, 2007), requires that the phosphorus level in finished biodiesel must be <10 ppm. For this reason, most soy-... 

Soybean oil is converted into soy FAME through transesterification with methanol. This product is an excellent substitute for diesel fuel with no engine adjustment required and no loss in efficiency (Knothe Dunn, 2005). Besides transesterification to methyl esters, other approaches also were explored for utilizing soybean oil as fuel. These are diluted with conventional petroleum diesel fuel, microemulsions (co-sol-vent blending), and pyrolysis (Schwab et al., 1987). A detailed discussion on biodiesel is provided in the Chapter Bioenergy and Biofuels from Soybeans, and also elsewhere (Knothe Dunn, 2005 Reaney et al., 2004). 

For fuel applications, a popular SBO derivative is methyl soyate (SBO methyl ester, also known as Soy Gold) (J). This biodiesel has several advantages over diesel fuel from petroleum sources because it is biodegradable, has a high flash combustion temperature, contains negligible amount of sulfur, is neutral with respect to carbon dioxide emission, and can potentially reduce many harmful exhaust emissions. Methyl soyate is also an increasingly useful industrial solvent for grease removal. 

Figure 8.15 Thermogravimetric and derivative curves for biodiesel (methyl esters from soy oil).

Canola or rapeseed (Brassica napus or B. campestris) is a bright yellow-flowering member of the Brassicaceae (also known as the mustard) family. It is cultivated for the production of animal feed, vegetable oil for human consumption, and biodiesel. Worldwide, canola was the third leading source of vegetable oil in 2000, after soy and palm oils. Canola is also the world s second leading source of protein meal. ... 

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