Preparation and application of Ca/Al composite oxide solid alkali catalyst for synthesizing biodiesel

Abstract

The invention discloses a preparation method and application of a Ca / Al composite oxide solid alkali catalyst for synthesizing biodiesel and belongs to the biodiesel synthesis technology field. The preparation method of the catalyst comprises the following steps: obtaining solid hydrated calcium aluminate through cooling, filtering and washing after sodium metaaluminate is reacted with lime milk in water, then obtaining Ca / Al composite oxide solid alkali through calcining the solid hydrated calcium aluminate and finally obtaining the Ca / Al composite oxide solid alkali catalyst after the Ca / Alcomposite oxide solid alkali is subjected to plasma treatment. The process of synthesizing the catalyst into the biodiesel is shown as follows: adding oil and alcohol maters (by molar ratio) and the catalyst (by mass ratio) into a rector, reacting at a temperature of 30-220 DEG C, under a normal pressure-0.5 MPa and under the agitation to obtain a mixture containing the biodiesel and then obtaining the biodiesel and glycerin by filtering the solid catalyst and stalling and layering. The invention has the advantages of simple catalyst preparation process, high activity when being used for synthesizing the biodiesel, long cycle and service life, no waste liquor discharge and environment protection in the process.

Description

technical field [0001] The invention relates to a preparation method and application of a Ca / Al composite oxide solid base catalyst for synthesizing biodiesel, and belongs to the technical field of synthesizing biodiesel. Background technique [0002] As a green, safe and renewable alternative energy source, biodiesel plays a very important role in ensuring the steady development of the world economy and reducing the pollution caused by fuel fossil energy to the earth's environment. So far, biodiesel can be prepared by physical or chemical methods, the latter being the main method, that is, using oil crops, wild oil plants, engineering microalgae and other aquatic vegetable oils and animal oils, waste cooking oil, etc. as raw materials, and methanol Or ethanol and other low-carbon alcohols undergo transesterification under catalysis or special process conditions to obtain long-chain fatty acid mono-alkyl esters. After separation, the long-chain fatty acid mono-alkyl esters c...

AI Technical Summary

Problems solved by technology

Although solid acid catalysts have shown certain activity in the transesterification reaction, the reaction needs to be carried out at higher temperature and pressure; compared with solid acid catalysts, there are more reports on the development of solid base catalysts. At present, there are many reports in the literature. A solid base catalyst (alkali metal, alkaline earth metal oxide and supported catalyst, hydrotalcite type solid base, zeolite molecular sieve, resin, etc.) is used to catalyze the synthesis of biodiesel. When these catalysts are used in the synthesis of biodiesel, the general reaction conditions are relatively mild , has high activity, and the yield of biodiesel (fatty acid methyl ester) is high, but the stability is not good, and the service life is short. Some supported catalysts are lost due to the dissolution of active components into methanol, resulting in a sharp drop in activity during repeated use.

Therefore, it is difficult to be used in industrial production