Method of preparing biological diesel oil using solid base catalyst

Abstract

The solid alkali catalyst process of preparing biodiesel oil includes the following steps: mixing vegetable oil and methanol or ethanol in the molar ratio of 4-20 mechanically in a reactor; adding solid alkali catalyst in 0.5-5 wt% of the vegetable oil and cosolvent in 5-20 wt% of the vegetable oil; performing ester exchange reaction at 60-85 deg.c via stirring for 1-4 hr; suction filtering while the reacted product is hot to separate out solid alkali catalyst; distilling the liquid phase to recover methanol; separating the liquid phase in a separating funnel into crude biodiesel oil in the upper layer and glycerin in the lower layer; and decompression distilling the crude biodiesel oil to obtain purified biodiesel oil product. Thus prepared biodiesel oil has simple post-treatment, and needs no neutralization and washing.

Description

technical field [0001] The invention relates to the technical field of green and renewable energy, and belongs to a new method for preparing biodiesel, in particular to a method for preparing biodiesel by using a solid alkali catalyst. Background technique [0002] Using oil crops such as soybeans and rapeseeds, fruits of oil trees such as oil palm and pistachio chinensis, engineering microalgae and other oil-bearing aquatic plants, animal fats, waste cooking oil, etc. as raw materials, the organic Fatty acid methyl ester or ethyl ester fuel is biodiesel, and the by-product is glycerin. The traditional process route for preparing biodiesel uses homogeneous catalysts, such as sodium methoxide, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, etc., the dosage accounts for about 1% of the oil weight, and the reaction temperature is not high, generally methanol Boiling point temperature, fast reaction speed, high conversion rate (above 95%). How...

AI Technical Summary

Problems solved by technology

The traditional process for preparing biodiesel uses homogeneous catalysts, such as sodium methoxide, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, etc., the dosage accounts for about 1% of the oil weight, and the reaction temperature is not high, generally methanol Boiling point temperature, fast reaction speed, high conversion rate (above 95%)

However, the separation of the catalyst in the homogeneous method is difficult, and a large amount of industrial wastewater will be generated in the post-treatment process, causing environmental pollution.

Using enzymes as catalysts can be recycled, and the reactants and products in the catalyst have a large mass transfer rate, but during the reaction, if the process and parameters are improperly grasped, it is easy to cause enzyme "poisoning" and affect the catalytic effect

In addition, the application of enzyme-catalyzed transesterification is limited due to high enzyme price, long reaction time and low reaction yield.

The supercritical non-catalytic transesterification reaction is carried out, the reaction time is short, the conversion rate is high, and the post-treatment is simple, but the molar ratio of alcohol to oil is high, and the reaction temperature and pressure exceed the critical temperature and critical pressure of methanol, which requires high equipment requirements.