Method for preparing low-cold-filter-plugging-point biodiesel

Abstract

The invention discloses a method for preparing low-cold-filter-plugging-point biodiesel, which comprises the following steps: (1) preparing free fatty acids by hydrolysis of raw material grease; (2) separating free fatty acids by a urea clathration process to obtain a fraction containing rich saturated fatty acids and fraction containing rich unsaturated fatty acids; and (3) performing esterification reaction of the fraction containing rich saturated fatty acids, which are obtained by the step (2), with short-chain alkanols and the esterification reaction of the fraction containing rich unsaturated fatty acids, which are obtained by the step (2), with methanol, uniformly mixing the two parts of fatty acid esters obtained by the reactions uniformly and obtaining the biodiesel with improvedlow-temperature flowing property. The method for improving the low-temperature flowing property of the short-chain alkanol biodiesel is simple in operation, is highly adaptive to raw material oils, and can realize high utilization rate; and the physical and chemical properties of the product prepared by the method meet the specified values of standards for biodiesel.

Description

technical field [0001] The invention relates to a method for improving low-temperature flow properties of biodiesel in the field of biochemical industry. Background technique [0002] Biodiesel is defined as long-chain fatty acid mono-alkyl esters, which are common oils and oil by-products such as vegetable oils, animal oils, microbial oils, microalgae oils, catering recycled oils, vegetable oil refining oil bottoms, acidified oils, etc. etc.) prepared by reacting with short-chain alkanols. Due to the low price of methanol, currently methanol is mainly used to produce biodiesel, and the resulting biodiesel refers to mixed long-chain fatty acid methyl esters. As a new type of renewable energy, biodiesel has the characteristics of renewable main raw materials, environmental friendliness, and can replace diesel oil, and has been widely researched and applied all over the world. [0003] Hu Zhen studied the preparation of biodiesel by using corn oil and methanol as raw materia...

AI Technical Summary

Problems solved by technology

It can be seen that the current production process of biodiesel is mainly prepared according to the method of one-step transesterification reaction between raw material oil and alkyl alcohol. This process is cumbersome in the subsequent treatment of impurities such as glycerin, and the production process is limited by the raw material oil. Due to the limitation of the production process, the production process is not fixed, which increases the difficulty of operation

At the same time, the current methods have certain problems in improving the low temperature flow properties of biodiesel.

At this stage, foreign countries, especially Southeast Asian countries, mainly use palm oil as the raw material for biodiesel production, while the domestic raw materials for biodiesel production are mainly gutter oil and some non-edible oils. The same feature of these raw material oils is high content of saturated fatty acids. The low-temperature flow properties of the obtained biodiesel products are not excellent enough, which seriously affects the popularization and use of biodiesel