Monomer-containing solvent refining system and process

Abstract

The invention discloses a monomer-containing solvent refining system and process. The system comprises a crude solvent tank and a heavy component removal tower, an outlet pipeline of the crude solvent tank is connected with a de-heavy tower kettle, the tower kettle and all sections in the tower are connected to a flash tank through overflow pipelines, a branch formed by converging a liquid phase outlet pipeline of the flash tank and an outlet pipeline at the bottom of the tower is connected with a reboiler, and the other branch is connected with a waste liquid tank; an outlet pipeline of the reboiler is communicated with the de-heavy tower; a gas phase outlet pipeline at the top of the tower and a gas phase outlet pipeline of the flash tank are converged and then connected with a condenser of the de-heavy tower; and a liquid phase outlet pipeline of the heavy component removal tower condenser and a liquid phase outlet pipeline at the tower top are converged and then are connected with a solvent recovery tank. According to the invention, the solvent containing the easily polymerizable monomer is refined, and the organic solvent can be obtained through high-efficiency and high-purity purification without adding a polymerization inhibitor or organic alkali.

Description

technical field [0001] The invention relates to a system and a process, in particular to a monomer-containing solvent refining system and process, belonging to the technical field of solvent refining. Background technique [0002] The polyacrylic acid thickener is made of acrylic acid as the main raw material, and the self-polymerization and crosslinking of the acrylic monomer are realized by the crosslinking agent under the action of the initiator, and then the polyacrylic acid thickening agent with super large molecular weight is obtained. The solvents used in the reaction are ethyl acetate and cyclohexane, the monomer conversion rate is 99%, the reaction product is a solid material, and the crude solvent needs to be purified and reused after the solid product is filtered. Among them, the impurities in the filtrate are mainly acrylic acid, ethyl propionate and oligomers of acrylic acid, but the content of acrylic acid and its oligomers in the solvent is higher than 300ppm ...

AI Technical Summary

Problems solved by technology

[0003] (1) The polymerization inhibitor has the risk of entraining the liquid foam to the top of the tower to recover the solvent, resulting in a high content of the polymerization inhibitor in the recovered solvent, which will affect the reaction time and rate of the free radical polymerization of the monomer after the solvent is reused;

[0004] (2) The reaction product of organic base and monomer still has the risk of self-polymerization in the tower kettle and the risk of organic base self-decomposition, and the selection of organic base requires long-term operation to verify its feasibility;

[0006] (1) Compared with the plate tower, the packed tower has higher separation efficiency under reduced pressure and normal pressure operation, but the packing cannot be directly used for materials that are easy to polymerize, and its anti-blocking performance is not as good as the plate tower;

[0007] (2) The void ratio between the packing and the tower wall in the packed tower is higher than that inside the packing, so when the liquid flows down the packing layer, it tends to gradually concentrate on the tower wall, so that the liquid flow near the tower wall gradually increases (ie Wall flow effect) will make the gas-liquid two-phase distribution in the packing layer uneven, thereby reducing the mass transfer and heat transfer efficiency

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