Dimethylamine treatment process in heat pump rectification process of synthetic leather DMF wastewater

Abstract

The invention discloses a dimethylamine treatment process in the heat pump rectification process of synthetic leather DMF wastewater. The dimethylamine treatment process comprises the following steps:sending the synthetic leather DMF wastewater into a rectifying tower, compressing tower-top steam of the rectifying tower through a two-stage steam compressor, sending compressed saturated steam intoa tower kettle heat exchanger of the rectifying tower to exchange heat with tower kettle materials, allowing part of heat-exchanged high-temperature water to flow back to the tower top of the rectifying tower, sending part of the heat-exchanged high-temperature water into a first buffer tank and a second buffer tank, treating remaining heat-exchanged high-temperature water, and sending treated remaining heat-exchanged high-temperature water into a water receiving pipe network; and spraying sulfuric acid into a pipeline through a first acid liquid spraying opening and a second acid liquid spraying opening to react with dimethylamine in steam so as to generate dimethylamine sulfate, allowing the dimethylamine sulfate in the first buffer tank and the second buffer tank to flow back and be sprayed into a first steam compressor discharging outlet pipeline and a second steam compressor discharging outlet pipeline, when the concentration of a dimethylamine sulfate solution is 40-45%, sendingthe dimethylamine sulfate solution into a crystallizing tank, and carrying out crystallization. The dimethylamine treatment process provided by the invention realizes highly-efficient removal of thedimethylamine in water vapor, reduces the corrosion of the dimethylamine to the tower kettle heat exchanger of the rectifying tower, improves the heat exchange coefficient of the tower kettle heat exchanger, and improves the environmental protection problem of odor generated by dimethylamine discharging.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a dimethylamine treatment process in the heat pump rectification process of synthetic leather DMF wastewater. Background technique [0002] N,N-Dimethylformamide (DMF) is a universal solvent widely used in the surface treatment of polyurethane (PU) synthetic leather in the synthetic leather industry. However, DMF is only used as a carrier solvent and does not react, so there is almost no loss and all of it enters the production wastewater. DMF is expensive and highly toxic. In order to reduce production costs and reduce environmental pollution, it is very necessary to recover DMF from synthetic leather wastewater. [0003] According to the different boiling points of water, DMF and other impurities, water and DMF can be separated by rectification. Heat pump rectification is a method that uses a steam compressor to compress the vapor at the top of the rectification...

AI Technical Summary

Problems solved by technology

The existence of non-condensable gas will greatly reduce the heat transfer coefficient of the tower kettle heat exchanger, reduce the heat transfer performance of the heat exchanger, and is not conducive to the vaporization of the tower kettle material

In addition, dimethylamine is a highly alkaline gas, which accumulates continuously in the heat exchanger of the tower kettle during the heat exchange process, and severely corrodes the heat exchanger made of stainless steel

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