Biodiesel is a fatty acid methyl ester obtained by esterification and transesterification of animal and vegetable oils with short-chain alcohols such as methanol. It is a renewable and clean energy source.
Brazil is vigorously promoting biodiesel production to reduce oil imports. The US Department of Energy is raising funds to develop biomass energy, requiring that by 2010, the US biomass energy use will be doubled, and biodiesel is also listed as one of biomass energy.
Internationally, the development of biodiesel is promising, and there are three main ways to manufacture biodiesel: one is to produce biodiesel from edible oil; the other is to use diesel cane to produce diesel; the third is to use “engineering microalgae” to produce diesel.
In order to improve the efficiency of diesel production, the enzyme immobilization technology is adopted, and methanol is added in stages during the reaction process, which is more conducive to improving the production efficiency of diesel. This immobilized enzyme (lipase) is derived from Candida Antartica (Candidaantaretica), which is used together with a carrier to produce a reaction column for diesel production at a controlled temperature of 30 ° C and a conversion of 95%. This lipase is still inactive for 100 days of continuous use. After the reaction solution has passed through several reaction columns, the reaction solution is allowed to stand, and the glycerin is separated, and it can be directly used as biodiesel.
In addition to the production of biodiesel by vegetable oil enzymatic method, there are also reports on the use of bagasse as raw material for the production of high-quality diesel. It is said that the energy of 1 ton of bagasse is equivalent to 1 barrel of oil (31.5 gallons per barrel, equal to 3 per gallon). .7853 liters). For example, a Canadian technology company is turning this achievement into productivity. It has built a 6-barrel biodiesel plant per day, producing diesel oil from bagasse, and plans to expand it into a 25-ton industrial-scale production facility. But what microbial fermentation is used to produce diesel? What is the output rate? No specific reports were seen.
The use of “engineered microalgae” to produce diesel is a noteworthy new trend in diesel production. The so-called “engineering microalgae” is a microalga constructed by genetic engineering technology, which opens up a new technical approach for diesel production. The National Renewable Energy Laboratory (NREL) has built “engineering microalgae”, a diatom-based “Cyclotella cryptica”, through modern biotechnology, to increase lipid content to 60 under laboratory conditions. More than % (the lipid content of microalgae in the natural state is 5%-20%), outdoor production can also be increased to more than 40%. This is due to the high expression of the acetyl-CoA carboxylase (ACC) gene in microalgae cells, which plays an important role in controlling the level of lipid accumulation. A suitable molecular vector is currently being studied to fully express the ACC gene in bacteria, yeast and plants, and further to modify the ACC.
Japan consumes 2 million tons of edible oil per year and produces 400,000 tons of waste cooking oil, which provides raw materials for the production of biodiesel. By transesterification by enzymatic method, lipase, the free fatty acids and water mixed in the reactant have no effect on the catalytic effect of the enzyme. After the reaction solution is allowed to stand, the fatty acid methyl ester can be separated from the glycerin, so that relatively pure diesel oil can be obtained. There are several points worth noting to be studied and used to produce biodiesel by this method: 1. Without the use of organic solvents, the high ester exchange rate is not achieved; When the methanol in the reaction system reaches a certain amount, the lipase is inactivated; The reaction time is relatively long; 4. In general, the price of the enzyme is higher.
The above biodiesel manufacturing method – esterification, transesterification, biodiesel produced should be called fatty acid methyl ester or ethyl ester, and the essential components of petrochemical diesel are essentially different from esters and hydrocarbons. At present, relevant biodiesel companies in Shangqiu can use the waste oil to produce biodiesel that meets EU standards…
In short, diesel is a common fuel used in urban and rural areas. Producing diesel through biological means is one of the most economical ways to expand the utilization of biological resources, and is one of the development directions of bioenergy. Energy biotechnology is bound to develop, and “non-polluting biodiesel” will certainly be more widely used. The use of waste oil to produce biodiesel can effectively solve the risk of returning the waste oil to the table, and benefiting the country and the people.