Continuous absorption method for byproduct hydrogen chloride gas in chlorination reaction

Abstract

The invention discloses a continuous absorption method of byproduct hydrogen chloride gas in a chlorination reaction, which comprises the following steps: allowing impurity-containing hydrogen chloride gas generated in the chlorination reaction to pass through a concentrated hydrochloric acid washing tank, sufficiently mixing the gas with concentrated hydrochloric acid, and washing to remove impurities; continuously feeding the washed hydrogen chloride gas into at least two stages of falling film absorption towers which are arranged in series, spraying and absorbing stage by stage, and feedingthe gas into a packing absorption tower for further absorption; allowing fresh absorption water to enter from the top of the packing absorption tower and sequentially flow through the packing absorption tower and the at least two stages of falling film absorption towers in a countercurrent mode, and feeding hydrochloric acid after absorption into a hydrochloric acid storage tank; allowing gas discharged from the top of the packing absorption tower to enter a spray tower again so that the gas is sprayed and absorbed by fresh absorption water and residual hydrogen chloride gas is further absorbed and then discharging at high altitude. According to the method, continuous absorption can be realized, no water-soluble impurities exist in the hydrochloric acid after absorption, and the absorption efficiency is high.

Description

technical field [0001] The invention relates to the technical field of chlorination reaction in chemical production, in particular to a continuous absorption technology of by-product hydrogen chloride gas in the chlorination reaction. Background technique [0002] In the chlorination reaction in chemical production, an excess of chlorine gas is generally maintained to ensure the completion of the chlorination reaction. The excess chlorine gas after the chlorination reaction is used as tail gas, which must be discharged after recovering chlorine gas. For example, the production process of bisphenol A bis(diphenyl phosphate) is that in the first step phosphorus oxychloride and bisphenol A generate bisphenol A bis(dichlorophosphate), and in the second step bisphenol A bis(dichlorophosphate) Phosphate) reacts with phenol to produce the target product. The hydrogen chloride gas produced in the two-step synthesis needs to be recovered by the hydrogen chloride gas recovery device ...

AI Technical Summary

Problems solved by technology

The disadvantage is that there is a lack of gas purification devices, and there are too many impurities in hydrochloric acid; each stage of hydrochloric acid absorption tower is equipped with hydrochloric acid absorption tanks and hydrochloric acid circulation pumps, which increases investment and operating costs

The second patent, CN101810986A, has the advantage of realizing continuous absorption of hydrogen chloride gas and continuous transfer of hydrochloric acid compared with the traditional process, saving an acid circulation pump and ensuring the stability of the concentration of hydrochloric acid; the disadvantage is that a two-stage falling film absorption tower is used to make the Hydrogen chloride gas is completely absorbed, and two hydrochloric acid absorption tanks and hydrochloric acid circulation pumps are added, which increases equipment investment and operating costs; and lacks gas purification devices, and there are too many impurities in hydrochloric acid

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