Method for extracting diketene from rectification residue and liquid after pump

Abstract

The invention relates to a method for extracting ketene dimer by rectifying residues and pumped liquid. The method comprises the following steps that firstly, hydrolysis is carried out, wherein primary residues and the pumped liquid are mixed in the proportion of 2:1 and heated to 65-75 DEG C through a membrane type evaporator, ketene dimer is evaporated out, crude ketene dimer obtained through cooling of a primary condenser and a secondary condenser enters a high-order storage tank and is mixed with crude ketene dimer generated in a polymerization section, and then mixed crude ketene dimer enters a rectifying section; secondly, secondary residues formed in the membrane type evaporator and acetic anhydride in the condensers enter a hydrolysis section for hydrolysis, and acetone, dilute acetic acid and solid waste residues are obtained; thirdly, tail gas at the hydrolysis section is fed to a water scrubber to be absorbed. The method has the advantages that crude ketene dimer is recycled through heating of the membrane evaporator, the yield of crude ketene dimer is increased inside the system, consumption of glacial acetic acid is reduced, waste gas and residues generated in the production process are digested and absorbed, solid waste is greatly reduced, and zero waste water emission is achieved.

Description

technical field [0001] The invention belongs to the production method of diketene prepared by acetic acid cracking method in the field of chemical production, in particular to a method for extracting diketene from rectification residue and liquid after pumping. Background technique [0002] Acetic acid cracking method is the main method for preparing diketene at present. Because diketene is a heat-sensitive substance, it is easy to form insoluble high polymers and self-polymers during the synthesis process, and these polymers constitute the main solid residue in the diketene process. The residue mainly contains acetic anhydride, diketene, ketene polymer, etc., and has a pungent odor. At present, the main treatment method for residues is hydrolysis. After recovering acetone and acetic acid after hydrolysis, the remaining residues are directly discharged into the environment, which will cause great pollution and waste valuable fuels and effective substances in the residues. ...

AI Technical Summary

Problems solved by technology

At present, the main treatment method for residues is hydrolysis. After hydrolysis, acetone and acetic acid are recovered, and the remaining residues are directly discharged into the environment, which will cause great pollution and waste valuable fuels and effective substances in the residues.

In addition, a large amount of gas is produced during the production of diketene, which is usually discharged directly, which will also cause great material loss and environmental pollution

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