Advantages of distilled biodiesel over non-distilled biodiesel

Biodiesel Distillation

The Advantages of Biodiesel Distillation

The search for non-fossil alternative fuels has been conducted now for more than a decade. The impetus for this search has increased in more recent years mainly due to the talk of supposed global warming; the incidence of which is increased by the release of CO2 into the atmosphere by fossil fuels. Because of the Kyoto protocols, one of the primary processes being perfected is that of making biodiesel. This type of diesel can be made from any type of fat or oil, but there are problems associated with its production and use. To mitigate these issues, firms have begun using a distillation process which, in most ways, fixes the problems that have commonly been associated with biodiesel. The following paper discusses what biodiesel is, how the fuel is made, what the distillation process is, and what advantages distilled biodiesel has over non-distilled biodiesel.

Biodiesel

Biodiesel was required as one of the products that would be further developed by companies, and be used in increasing amounts by all agreeing nations. "The 'Kyoto Protocol' -- which is the United Nations framework convention on climactic change -- requires the introduction of biofuels into the transport fuel market in order to reduce greenhouse gas emissions" (Lurgi). This charge was specifically in relation to all biofuels, but biodiesel has been the prominent result of this part of the agreement. The protocols provided the impetus for the sustainable fuels industry to really make usable biofuels.

The fuel itself is formulated to emulate fossil fuel diesel, but it does not contain the same harmful properties. "Biodiesel is a biodegradable ester that does not contain the dangerous element sulfur. In addition, the plants from which the vegetable oils are produced, capture more CO2 from the atmosphere than the amount that these oils release during their combustion" (Matallana, Gutierrez & Cardona). It is worth noting that these are two advantages of biodiesel in general. Because much of the fuel is made from vegetable matter, the CO2 released during production and burning is negligible. Of course, the fact that this fuel does not contain sulfur is an added bonus. This means that two of the harmful products resulting from the burning of fossil diesel are lost when biodiesel is used instead.

Production

The production of biodiesel is a process that requires a complex plant, but it is no more limiting than refining other fuels. The process is also not static. There are many different methods that the producer can use to produce the biodiesel. It "can be made from vegetable oils or animal fats transesterfication or alcoholysis, enzymatic or lipase conversion, and thermal cracking or pyrolysis" (Singh, Thompson & He). It should be noted that fossil diesel is a non-regenerating product; however, biodiesel is completely sustainable because any oil can be used for the process to occur.

Distillation

However, there is a problem with biodiesel that requires a second step in the production process. The issue is that there is a great variability within the different component fats used, and this means that there is an equal variability in the effectiveness of the biodiesel produced. The American Society for Testing and Materials (ASTM) has designed tests for biodiesel because the "Variability in the quality of biodiesel, coupled with the high cloud point of biodiesel produced from certain feedstocks, has resulted in the ASTM adopting more stringent biodiesel standards" (SRS Engineering). By cloud point the quote is referring to the temperature below which solids reform in the fuel causing it to take on a cloudy appearance. This causes engine problems because the solids will clog filters and injectors. Engine performance is greatly reduced and it can be damaged. However, the ASTM has developed a process by which fuels can be tested for acceptability. "The new ASTM D6751 cold soak filterability test is a measure of how well biodiesel flows when chilled then poured through a filter" (SRS Engineering). This is basically a viscosity test for the furl, but this cold filtering will also determine at what temperature the fuel begins to develop a cloudy appearance. The process has helped researchers determine which products do not provide acceptable biodiesel. But there is a process by which the cold filtering can be eradicated in the fuel. "Distilling…biodiesel produces the purest form of biodiesel possible and dramatically reduces cold filterability of most feedstocks" (SRS Engineering). Thus a process by which the diesel is further distilled will take away the problems associated with reduced temperatures in most oils that have been tested.

The process of distilling the biodiesel is done in a plant that is specifically designed for the process. The process is conducted as follws:

"Transesterification is based on the chemical reaction of triglycerides with methanol to form methylesters and glycerine of an alkaline catalyst. The reaction is a two-stage mixer-settler unit. Transesterification in the mixing section, while the subsequent settling section allowsfor the separation of methylesters as the light phase from glycerine water as the heavy phase. A subsequent countercurrent washing step for the methylester removes minute by-product components and gives a biodiesel 'ready for use' after the drying step" (Lurgi).

This process takes the biodiesel that was constructed from any form of fat or oil and breaks it down so that the components are basically the same in all fuels. The distillation process produces advantages that cannot be realized from undistilled biodiesel.

Conclusion

Biodiesel is definitely superior to fossil diesel, can be produced more effectively from sustainable processes, and, when distilled, becomes even better. However, there are still problems that exist. One issue is that "almost all of the existing processes utilize excess alcohol, which must be recovered in additional separation process. This recovery process generally involves distillation, which increases energy consumption and process time" (Singh, Thompson & He). This means that recovering the alcohol adds to the cost of production and distillation. This issue is being solved by manufacturers, but even without a solution to this issue, it is clear the distilled biodiesel is a superior product.