Process for recovering benzene-containing tail gas from preparation of cis-butenedioic anhydride by benzene oxidation

Abstract

The invention discloses a process for recovering benzene-containing tail gas from the preparation of cis-butenedioic anhydride by benzene oxidation, which comprises the following steps that: after entering a dehumidifier to reduce liquid water content, a tail gas exhausted from a production device enters a primary absorption tower and passes through the primary absorption tower and a secondary absorption tower at 30 to 40 DEG C and 0.12 MPa, wherein the total adsorption rate of the primary absorption and secondary absorption can reach 99.7 percent and the total recovery rate of the primary absorption and the secondary absorption is up to 95 percent; the tail gas subjected to the secondary absorption has a benzene content less than the national discharge standard of 12mg / m and can be discharged directly; when the absorption rate of the absorption towers reach 90 percent, vapor at a high temperature of 110 DEG C introduced into the absorption tower for desorption, and desorbed benzene-containing vapor is subjected to condensation and gravity segregation to recover benzene; and when the absorption rate of the absorption towers reaches above 90 percent, the absorption towers are dried by introduced drying hot air and change into an absorption state again. The process has the advantages of achieving high benzene recovery rate, effectively recovering the benzene, creating considerable economic benefits, discharging the tail gas after the tail gas reaches the standard, and creating remarkable social benefits.

Description

technical field [0001] The invention relates to an adsorption and recovery process for benzene-containing tail gas, in particular to an adsorption and recovery process for benzene in benzene tail gas containing a large amount of saturated water vapor produced during the benzene oxidation process to produce maleic anhydride. Background technique [0002] Maleic anhydride, also known as maleic anhydride, chemically named maleic anhydride, is an important organic chemical raw material, the third largest anhydride after phthalic anhydride and acetic anhydride. At the end of 2007, the production capacity of maleic anhydride in my country was about 900,000 tons , by 2010, it will reach 1.3 million tons, and the market demand is large. Maleic anhydride is mainly used in the production of unsaturated polyesters and alkyd resins, and is also used in pesticides, paints, inks, lubricating oil additives, paper chemicals, textile finishing agents, surfactants and other fields. Maleic anh...

AI Technical Summary

Problems solved by technology

However, in the existing industrial VOCs waste gas recovery technology, the condensation recovery technology can only deal with small air volume and high concentration of VOCs waste gas; the adsorption recovery process uses adsorbents, and the saturated water vapor in the tail gas will cause VOCs components in the adsorbent bed. Rapidly penetrate through the layer, and the adsorption efficiency is very low, so it cannot be directly used for the recovery and reuse of useful VOCs components in this type of exhaust gas

At present, most domestic production enterprises using benzene oxidation method to produce maleic anhydride directly discharge without any treatment, which not only causes a lot of waste of benzene resources, but also causes serious environmental pollution, and also violates the relevant environmental protection laws and regulations of our country. Investment in pollution control, increasing environmental protection efforts, and building a harmonious society are incompatible with the environment

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