Production method of coking crude phenol by cyclic decomposition by gas and co-producing light calcium carbonate

Abstract

The invention relates to a production method of coking crude phenol by cyclic decomposition by gas and co-producing light calcium carbonate and aims to be convenient and reasonable to operate and reduce equipment corrosion. The production method comprises the following steps: distilling high-temperature coal tar to obtain a carbolic oil, naphthalene oil and absorber oil mixed fraction, and washingthe fraction in a vertical washing tower with NaOH aqueous solution to remove phenol; conveying a sodium phenolate solution to the upper part of a primary decomposition tower to be in reverse contactwith CO2 mixed gas to be decomposed to generate crude phenol and sodium carbonate; stationarily separating crude phenol and a Na2CO3 solution; conveying primary crude phenol to the upper part of a secondary decomposition tower to be further decomposed; feeding the separated Na2CO3 solution to a causticizer, wherein the cruder phenol self-flows to a crude phenol product tank, and causticizing mother liquor self-flows to a filtering centrifugal machine to separate solid CaCO3 and a liquid NaOH aqueous solution; lifting the solid CaCO3 to a washer to be washed by a vertical lift, wherein the solid CaCO3 self-flows to the filtering centrifugal machine; and feeding the solid CaCO3 into a roller drier by a belt conveyor, and drying the solid CaCO3 for 20 minutes at 300-350 DEG C to prepare a light calcium carbonate semiproduct.

Description

technical field [0001] The invention belongs to the technical field of deep processing of high-temperature coal tar, and in particular relates to a production method of gas circulation coking crude phenol and co-production of light calcium. Background technique [0002] The industrial method for extracting phenolic substances from high-temperature coal tar is to firstly distill the coal tar to obtain a mixed fraction of phenol oil naphthalene oil washing oil with a relatively high phenol content. Then wash the fraction with NaOH aqueous solution to separate the phenolic substances. The principle is that NaOH reacts with phenolic substances to form a sodium phenolic salt solution (this process is also called the washing process). Crude phenol is then obtained by decomposing the sodium phenolate with an acidic substance (this process is also called the decomposition process). At present, the production of crude phenol by the decomposition of phenol sodium salt in my country m...

AI Technical Summary

Problems solved by technology

Although this method solves the problem of waste liquid discharge, there are still problems of equipment corrosion and unreacted SO2 affecting the operating environment. Currently, only a few enterprises are using it

When pure CO2 is used for decomposition, due to the high concentration of CO2, local CO2 in the decomposition equipment (decomposition tower) will be excessive, and excessive CO2 will generate sodium bicarbonate (NaHCO3), which has low solubility in water and crystallization Generate clogging equipment, affecting the operating cycle

The decomposition of phenolic sodium salt is an important link in the extraction of phenolic products from coal tar. From the perspective of several methods currently used in my country, there are common problems of equipment corrosion, short production cycle and environmental impact of waste gas.

If simply using CO 2 Decomposition, the resulting phenolic sodium carbonate solution will pollute the environment

Therefore, it is necessary to develop a new production process for refining, separating and extracting crude phenol from coal tar to solve the problem of equipment corrosion and the impact on the environment in the decomposition process of sodium phenol salt

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