Method for producing carboxylic acid with high added value by hydrothermal oxidation of coal or coal liquefaction residues

Abstract

The invention relates to a method for producing carboxylic acid with high added value by hydrothermal oxidation of coal or coal liquefaction residues. The method comprises the following steps: providing coal or coal liquefaction residues as a substrate; mixing the substrate and water, placing the mixture in a reaction kettle, and communicating a liquid storage cavity which is separated from the reaction kettle and is used for storing an oxidizing agent with the reaction kettle; then raising the temperature of the reaction kettle to 70-180 DEG C or above, dropwise adding an oxidizing agent into the substrate in a stirring state, and reacting for 0.2-1.5 hours to obtain an oxidized substrate; and filtering and separating the oxidized substrate to obtain a carboxylic acid product. The reaction kettle is adopted as a reaction container, a reaction sample and the oxidizing agent are separated, a hydrothermal oxidation technology is innovatively provided, the oxidizing agent is added drop by drop according to the constant-pressure liquid dropping principle under the hydrothermal condition, the reaction speed is increased, the reaction time is remarkably shortened, and the oxidation efficiency is improved; and the whole environment is changed from an oxidizing reaction environment to a reducing reaction environment, so that the problem of product peroxidation is reduced, and resources are saved.

Description

technical field [0001] The application relates to a method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue. Background technique [0002] Coal oxidation is an important method for the production of carboxylic acids, especially high value-added benzene polycarboxylic acid. A large number of scholars have conducted exploratory experiments. However, in order to achieve the purpose of oxidation and avoid uncontrollable oxidation processes, the current research on coal solid-liquid oxidation reaction It is mostly carried out below 50°C. Due to the low reaction temperature, the added oxidant reacts slowly and the reaction time is longer, usually more than 12 hours. In addition, a large amount of unreacted oxidant will make the reaction kettle an oxidizing environment, resulting in excessive carboxylic acid products. Oxidation reduces the yield of oxidized products. After the oxidation reaction starts, the heat released...

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Problems solved by technology

[0002] Coal oxidation is an important method for the production of carboxylic acids, especially high value-added benzene polycarboxylic acid. A large number of scholars have conducted exploratory experiments. However, in order to achieve the purpose of oxidation and avoid uncontrollable oxidation processes, the current research on coal solid-liquid oxidation reaction It is mostly carried out below 50°C. Due to the low reaction temperature, the added oxidant reacts slowly and the reaction time is longer, usually more than 12 hours. In addition, a large amount of unreacted oxidant will make the reaction kettle an oxidizing environment, resulting in excessive carboxylic acid products. Oxidation, reducing the yield of oxidized products

After the oxidation reaction starts, the heat released by the reaction will increase the temperature in the reactor, thereby promoting the acceleration of the oxidation reaction. Repeatedly, it is easy to cause thermal runaway and even explosion accidents.

[0003] Coal liquefaction to produce liquid fuel is an important method to alleviate the shortage of oil, and it is also an extremely important strategic technology. In the process of coal liquefaction, about 20% of the liquefaction residue will be produced by-product. These residues have high ash content and high carbon content. The treatment of liquefaction residue is difficult, but coal liquefaction residue usually contains a high degree of condensation of aromatic rings, which is an important raw material for the preparation of aromatic polyformic acid, but its oxidation at room temperature has similar problems to coal oxidation

[0004] The existing room temperature oxidation method of coal and its liquefaction residue has the problems of long reaction time, easy peroxidation of the product, and difficult control of the reaction

Existing technology has no solution for this

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