Enzyme method technique for improving bio-diesel yield by adding short-chain alcohol in organic medium

Abstract

The invention relates to an enzyme method technology for improving biological diesel oil yield through replenishing chain alcohol in organic medium, which belongs to the biological diesel oil synthesis field. Short chain alcohol and oil whose molar ratio of methanol to oil is 3:1-10:1 are reacted in any biochemical reactors which are suitable for enzyme reaction on the basis of tert-butanol which is 20-200% of the volume of oil and lipase which occupies 2-20% of oil quality, wherein the temperature is controlled between 30 DEG C to 65 DEG C, when biological diesel oil yield rate reaches 60-96%, short chain alcohol such as carbinol or alcohol whose molar ratio of methanol to oil is 3:1-10:1 is replenished in the above reaction system, namely mole ratio of short chain alcohol and initial oil which are added is 3:1-10:1, the short chain alcohol can be added in the model of one time replenishment and several times replenishment, which continuously reacts for 3-10 hours, oil raw material which can be conversed can nearly and completely be conversed to be biological diesel oil. The reaction can go on intermittently or continuously, lipase can be a single lipase, and can be the combinations of lipases with different performance. The enzyme method technology has the advantages that the enzyme method technology is convenient to be operated in industry, which obviously saves investment and energy consumption.

Description

technical field [0001] The invention belongs to the field of biodiesel synthesis, and in particular relates to an enzymatic process for increasing the yield of biodiesel by adding short-chain alcohols in an organic medium system. Background technique [0002] Biodiesel is a long-chain fatty acid ester substance produced by transesterification of bio-oil raw materials. It is a new type of pollution-free renewable energy, called biodiesel. Its combustion performance is comparable to that of traditional petroleum diesel. Currently, the research and application of biodiesel has received extensive attention. [0003] At present, biodiesel is mainly produced by chemical method, that is, transesterification is carried out with animal and vegetable oils and some low-carbon alcohols (methanol or ethanol) under the action of alkali or acidic catalysts to generate corresponding fatty acid methyl esters or ethyl esters. There are some unavoidable disadvantages in the preparation of bio...

AI Technical Summary

Problems solved by technology

There are some unavoidable disadvantages in the preparation of biodiesel by chemical method: ① The free fatty acid and water in the oil raw material seriously affect the progress of the reaction; ② The solubility of methanol in oil is not good, which easily leads to the formation of emulsion and complicates the subsequent treatment process ; ③ The process requires that the amount of methanol used greatly exceeds the reaction molar ratio, and the evaporation and reflux of excess methanol increases the energy consumption of the process

It is reported in [Shimada Yuji et al. Enzymatic alcohol production and application of thereaction to oil processing, Journal of Molecular Catalysis B: Enzymatic, 2002, 17: 133-142] that short-chain alcohols such as methanol and ethanol are used in oil raw materials The solubility of the lipase is poor, which is not conducive to the reaction; secondly, the existence of excess alcohol will lead to severe inactivation of lipase, so in the process of biodiesel production by bio-enzyme, the method of adding short-chain alcohol in batches is often used ways to mitigate its toxic effect on enzymes

This method is cumbersome to operate and takes a long time to react. In addition, when short-chain alcohols are used as the acyl acceptor for the reaction, glycerol is produced as a by-product during the reaction, and the hydrophilic glycerol is easy to attach to the inner hole and outer surface of the immobilized enzyme. Thereby forming a "shield" to the active site of the enzyme, seriously affecting the enzyme reaction activity; in order to improve the above situation, some scholars try to use organic solvent reaction system to synthesize biodiesel, the literature [Shimada Yuji et al.Enzymaticalcoholysis for biodiesel fuel production and application of the reaction tool processing, Journal of Molecular Catalysis B: Enzymatic, 2002, 17: 133-142] report: some organic solvents with strong hydrophobicity such as hexane, cyclohexane, sherwood oil etc. are used as reaction medium

These hydrophobic organic solvents can dissolve oil well, and can promote the reaction to a certain extent; but because these organic solvents with strong hydrophobicity cannot effectively dissolve low-carbon alcohols such as methanol and by-product glycerin, they are not suitable for enzyme reactions. Activity, enzyme life and biodiesel yield have not improved significantly