Biodiesel fuel and preparation method thereof

Abstract

The invention relates to the field of petrochemical complex and particularly relates to a biodiesel fuel and a preparation method thereof. The preparation method of the biodiesel fuel comprises the following steps: step 1, using carbon dioxide to replace air inside an esterification reaction kettle, putting monomer acid into the esterification reaction kettle heated by conduction oil, and meanwhile adding high-temperature resisting big-hole phenethylene highly acidic cation exchange resin; step 2, heating a material inside the esterification reaction kettle to reach a temperature of 130 to 160 DEG C within 30 minutes, and continuously adding DMM; step 3, stopping DMM adding when the acid value of the material is smaller than 1mg KOH / g, and emptying when the temperature of the material is reduced to be lower than 80 DEG C, so as to obtain a biodiesel semi-finished product; step 4, adding a composite catalyst and stirring sufficiently when the biodiesel semi-finished product is cooled to be a temperature of 30 DEG C, namely a finished product is obtained. The biodiesel prepared through the method provided by the invention is excellent in water resistance, insoluble in water, and excellent in starting performance in winter, can be matched and mixed with petroleum diesel according to any proportion and has excellent economic benefits.

Description

technical field [0001] The invention relates to the field of petrochemical industry, in particular to biodiesel and a preparation method thereof. Background technique [0002] Biodiesel is mainly produced by chemical method, using animal and vegetable oils and low-carbon alcohols such as methanol and ethanol to carry out transesterification reaction under inorganic strong acidic or strong basic catalyst and high temperature to generate corresponding fatty acid methyl ester or ethyl ester, and then undergo Wash and dry to obtain biodiesel. Methanol or ethanol can be recycled in the production process, and glycerin, a by-product, can be produced in the production process. Synthesizing biodiesel with this process has the following disadvantages: the process is complicated, and subsequent treatments such as washing and drying are required, which greatly increases the production cost. [0003] Recently, people have begun to study the synthesis of biodiesel by biological enzyme ...

AI Technical Summary

Problems solved by technology

Using this process to synthesize biodiesel has the following disadvantages: the process is complicated, and subsequent treatments such as washing and drying are required, which greatly increases the production cost

But the main problems at present are: the conversion rate of methanol and ethanol is low, generally only 40%-60%, because lipase is effective for the esterification or transesterification of long-chain fatty alcohols, but for short-chain fatty alcohols such as methanol or ethanol conversion rate is low

Moreover, short-chain fatty alcohols have certain toxicity to enzymes, which shortens the service life of enzymes.

The by-product glycerol and water are difficult to recover, not only inhibiting the formation of the product, but also glycerol is toxic to the immobilized enzyme, and can also shorten the service life of the immobilized enzyme

[0004] At present, most of the raw materials for biodiesel production at home and abroad are animal and vegetable oils. For example, the publication number is CN1570029, and the Chinese invention patent application titled "Method for preparing biodiesel from natural oils" discloses that natural oils are used as raw materials. Under the action of an acidic catalyst, the transesterification reaction with 1-3 carbon molecular weight is carried out. This method requires steps such as dehydration, dealcoholization, separation of glycerin, and distillation. The process is relatively complicated and the energy consumption is relatively large, which greatly increases the production cost of the product.

However, there are not many relevant reports about directly using fatty acids as raw materials to produce biodiesel. For example, the publication number is CN1060089, and the Chinese invention patent entitled "C6-24 fatty acid semi-continuous methylation reaction operation method and optimization" discloses: -24 Saturated and unsaturated fatty acids are used as raw materials, and methyl hydrogen sulfate is used as a catalyst to carry out esterification reaction with methanol. The production method is relatively simple and the reaction time is relatively short. Toxic substances, which bring great hidden dangers to production safety

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