Domestic popular biodiesel process

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author: Ning Shojian (Expert Member of the National Biodiesel Industry Collaboration Group of Shenyang University) There are currently a variety of biodiesel technologies in China, with 301 patent applications (as of November 5, 2007) and countless papers. Among them, the vast majority are articles published or applied for patents for "innovation", but there are not many actual production processes. After a period of summary, I believe that there are currently three processes that can be put into actual production and are in use.: 　　1. Acid-alkali two-step method: This is the most traditional process and is also a process commonly used by general enterprises that independently develop technology. ； Its advantages are low energy consumption, good mastery can truly "distillation-free", and there are many technical reference materials. ； The disadvantage is that it requires acid-alkali conversion and has strict requirements on the acid value, impurities, water, etc. of the esterified materials. Saponification is easy to occur and the amount of waste water is large. 　　2. Separation reaction method: This is also adopted by many companies unconsciously. The main idea is to use distillation (steam stripping) to separate fatty acids, first achieve physical separation of fatty acids and neutral oils, and then use esterification and alkali-catalyzed transesterification of fatty acids and neutral oils respectively to react to obtain unified methyl esters. The advantages of this method are that the process is simple, easy to master, and the product sales are more flexible. ； The disadvantages are high energy consumption and high equipment requirements (especially corrosion resistance). 　　3. Complete acid catalysis method: This is a method adopted by myself and some companies. The advantage is that it has low requirements for raw materials, can handle basically all raw materials, and uses a non-water-washing process. ； The disadvantages are high energy consumption (second among the three methods) and high corrosion resistance requirements for esterification equipment. 　　4. It should be added that the acid catalysis method is especially suitable for plant crude oil. For oil-producing crops such as Jatropha curcas, which are currently in hot development, the squeezed crude oil does not need to be refined and directly enters acid catalysis. Traditional alkali catalysis requires strict refining before entering the catalytic process.