Method utilizing supercritical catalysis process to continuously prepare biodiesel

Abstract

The invention discloses a method utilizing a supercritical catalysis process to continuously prepare biodiesel, and relates to a preparation method of biodiesel. The method uses a solid catalysis fixed-bed reactor to carry out continuous biodiesel production. The ester exchange reaction is carried out at a temperature of 260 to 330 DEG C under a pressure of 10 to 19 MPa, and the alcohol / oil mole ratio is in a range of 35:1 to 70:1. The ester exchange reaction is carried out for 1.5 to 3 minutes in the reaction tube of the fixed-bed reactor in the presence of a catalyst, the reaction product is transported to a gas / liquid separator to carry out primary separation, the upper layer methanol is recycled, the middle layer and the lower layer are coarse biodiesel and coarse glycerine, and the coarse biodiesel and the coarse glycerine are respectively subjected to post refining treatments. Through detection, people find that the grease conversion rate is 90% to 100%. Advantages of conventional supercritical methanol method for preparing biodiesel are all preserved, furthermore, a fixed-bed catalyst and a continuous production technology are used, and thus the difficult conditions of supercritical reactions are greatly improved. Moreover, no impurity is introduced into the system during the reaction process, so the biodiesel post-treatment is largely simplified.

Description

technical field [0001] The invention relates to a method for preparing biodiesel, in particular to a method for continuously preparing biodiesel by supercritical catalysis. Background technique [0002] Extensive use of oil will lead to energy depletion and increase in greenhouse gas emissions. In order to achieve the harmonious development of economy and environment, it is necessary to use renewable energy instead of petroleum. The so-called "renewable energy" refers to animal and vegetable oils; while biodiesel is a mixture of fatty acid esters obtained by transesterification of animal and vegetable oils and low molecular weight alcohols (such as methanol, ethanol), such as fatty acid methyl esters, fatty acid Ethyl esters, fatty acid propyl esters, etc. Compared with traditional diesel, biodiesel has the following advantages: renewable raw materials, reducing dependence on petroleum; good lubrication performance; safe storage, transportation, use, and good anti-knoc...

AI Technical Summary

Problems solved by technology

This method avoids the problems encountered in the preparation of biodiesel by the conventional acid-base method, but the solid catalyst is added to the reactants, resulting in complicated operation and increased cost of the separation catalyst process

[0011] Looking at the above, it is true that the acid-base method in biodiesel production has its unavoidable disadvantages, while the simple supercritical method has the problem of harsh operating conditions

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