Biodiesel waste

Production costs for biodiesel from soybean oil exceeds 2.00 per gal ( 0.53 per 1), compared to 0.55 to 0.65 per gal ( 0.15 to 0.17 per 1) for conventional diesel. The main cost in biodiesel is in the raw material. It takes about 7.7 lb (3.5 kg) of soybean oil valued at about 0.25 per lb (0.36 per kg) to make 1 gal (3.81) of biodiesel. Waste oils, valued at 1 per gal ( 3.79 per 1) or less, have the potential to provide low feedstock cost. However, much waste oil" is currently collected, reprocessed as yellow and white greases, and used for industrial purposes and as an animal feed supplement. Production of biodiesel... 

Massive building of homogeneous biodiesel plants will yield a sharp increase in associated biodiesel wastes, which will need a remedial solution. 

Pattaraluk, J., Sangkom, K., Mah, H. (2010). Management of biodiesel waste water by the combined processes of chemical recovery and electrochemical treatment. Energy Conversion and Management, 51, 531—537. 

Chi Z, Pyle D,Wen Z, Frear C, Chen S. A laboratory study of producing docosahexaenoic acid from biodiesel-waste glycerol by microalgal fermentation. Process Biochem 2007 42 1537. 

Ruhal R, A arwal S, Choudhury B. Suitabihty of crude glycerol obtained from biodiesel waste for the production of trehalose and propionic acid. Green Chem 2011 13 3492-8. 

Ruhal R, Choudhury B. Use of an osmotically sensitive mutant of Propionibacterium freudenreichii subspp. shermanii for the simultaneous productions of organic acids and trehalose from biodiesel waste based crude glycerol. BioresourTechnol 2012 109 131-9. 

The implementation of biorefineries will help to increase the economic viability of the biofuel industry. Disposing glycerol with methanol in it can pose harmful side effects to humans and the environment. Biorefineries will prevent the major issues pertaining to the disposal of biodiesel waste. The processing of oils and fats within the concept of a biorefinery and the chemical recovery and production of other valuable products is shown in Fig. 19.5. 

Many home brewers are producing soap from biodiesel waste (glycerin). 

During the last decade many industrial processes shifted towards using solid acid catalysts (6). In contrast to liquid acids that possess well-defined acid properties, solid acids contain a variety of acid sites (7). Sohd acids are easily separated from the biodiesel product they need less equipment maintenance and form no polluting by-products. Therefore, to solve the problems associated with liquid catalysts, we propose their replacement with solid acids and develop a sustainable esterification process based on catalytic reactive distillation (8). The alternative of using solid acid catalysts in a reactive distillation process reduces the energy consumption and manufacturing pollution (i.e., less separation steps, no waste/salt streams). 

Zhang Y, Dube MA, Mclean DD, Kates M (2003) Biodiesel production from waste cooking oil 1 Process design and technological assessment. Biores Tech 89 1-16... 

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. 

Current biodiesel can not be considered as a 100% biomass-based fuel as long as methanol is derived from petrochemical resources. A clean way to solve the biorelated problem is the conversion of glycerol waste from the transesterification process into syngas. In this context, glycerol reforming is a suitable target reaction worthy of study. 

In conclusion, the economically competitive, non-subsidized production of liquid biofuels requires (a) the use cheaper and more reliable sources of renewable raw material (b) efficient conversion, with minimum waste, of cellulosic, fiber or wood-based, waste biomass into fermentable sugars (c) significantly improved efficiency of the production processes and (d) use by-products (e.g., glycerol in biodiesel production). Several of these aspects are discussed in details in various chapters. 

The alternative fuels FT and DME fuels can be mannfactnred from natiual gas and are therefore not limited by feedstock availabiUty. Biodiesel on the other hand, is prodnced from vegetable (and some waste animal) oils whose supply for non-nutritional uses is presently quite limited. 

The use of heterogeneous basic catalysts for the transesterification of triglycerides has long been considered the main tool to reduce processing costs in the production of biodiesel, as it would lead to simplified operations and eliminate waste streams. 

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