Method for preparing biodiesel through high-temperature esterification reaction of high acid value oil

Abstract

The invention discloses a method for preparing biodiesel through high-temperature esterification reaction of high acid value oil, belonging to the technical field of biodiesel preparation. The method comprises the following steps: (1) esterification reaction, adding the high acid value oil and a catalyst into an esterification reactor, dripping methanol into the esterification reactor by using a dripping device for esterification reaction, meanwhile, cooling unreacted methanol and moisture generated in reaction by using a condensing device, and after the reaction is finished, removing the methanol and the moisture through distillation to obtain a biodiesel crude product; and (2) distillation treatment, distilling the obtained biodiesel crude product under reduced pressure, and collecting fraction, namely a biodiesel finished product. The method disclosed by the invention realizes the one-step esterification reaction of the high acid value oil under the conditions of normal pressure and high temperature, and the esterification process and the water cooling and removal are carried out simultaneously for the preparation of the biodiesel, so that the method has the advantages of easy process, short production cycle, low energy consumption and the like, is easy to industrially produce, and can significantly increase the yield of the biodiesel per unit time and the output of a single kettle.

Description

[0001] technical field [0002] The invention belongs to the technical field of new biological energy, and in particular relates to a method for preparing biodiesel through high-temperature esterification of oil with high acid value. [0003] Background technique [0004] In recent years, due to the depletion of petroleum resources and the global ecological environment change caused by the use of fossil fuels, the development of bioenergy with the advantages of renewable and green environmental protection has been paid more and more attention by people. An important product in bioenergy is biodiesel, which is high acid value oil methyl ester, which is a clean and renewable energy source. It mainly uses long carbon chain fatty acids, acidified oil, gutter oil and other high acid value oils as raw materials It is a liquid fuel that can replace petroleum diesel and is synthesized by esterification with other low-carbon alcohols such as methanol or ethanol. It has the advantage...

AI Technical Summary

Problems solved by technology

[0006] At present, biodiesel preparation technology is not mature, and there are many defects. Some processes are harsh or equipment requirements are too high, and industrial mass production cannot be realized. For example, Chinese patent CN1654601 discloses "a method for preparing biodiesel", which is in ultrasonic esterification It is carried out in the reactor, and the water content of the raw material oil is required to be below 0.07%.

Some esterification reactions to prepare biodiesel have a low esterification rate and are carried out in multi-step esterification reactions. The cycle is too long, the process is complicated, and the production cost is high. For example, Chinese patent CN101624534A discloses "A Method for Esterification of Methanol in Biodiesel Production" , the entire methanol esterification process is divided into three esterification reactions, three dehydration and methanol, and the conversion rate of methanol esterification is low

In some esterification reactions to prepare biodiesel, the amount of acid catalyst added is too much. Because the acid is corrosive, there are potential defects such as deepening of product color and corrosion of equipment. For example, Chinese patent CN101508904A discloses "production method of biodiesel". The bio-oil treated by heating and dehydration is used as the raw material, and the concentrated sulfuric acid is used as the catalyst to carry out the esterification reaction with methanol. The entire esterification reaction is divided into two esterifications. The longest time is 14.5 h, and the amount of concentrated sulfuric acid added is 3% of the mass of methanol.

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