NMP recovery and purification method and system

Abstract

The invention relates to an NMP recovery and purification method and system. According to the method, firstly, heat pre-exchange is conducted through a plate exchanger; secondly, secondary heat exchange and third heat exchange are conducted by combining with a normal temperature water meter cooler and a refrigeration water meter cooler respectively. Heat energy is recovered through hierarchical progressive heat exchange, so that not only is the energy consumption for heating of production equipment reduced, but also the refrigeration capacity of the refrigeration water meter cooler can be effectively decreased, and therefore the equipment size of refrigeration units associated with the refrigeration water meter cooler is greatly decreased. A recycling part is also designed for closed-loopoperation, and the air discharge amount is 1 / 10 of the total amount of air discharged by the system. Compared with a full air amount processing system, the system has the advantages that the energy consumption is effectively reduced, the system is suitable for large-scale application, the occupied space is small, the energy consumption is low, and the operation cost is low.

Description

technical field [0001] The invention belongs to the technical field of waste gas treatment, and in particular relates to a method and system for recovering and purifying NMP. Background technique [0002] NMP, that is, N-methylpyrrolidone, has the advantages of high flash point, good safety, and good dissolution and dilution performance for the adhesive PDVF, so it is widely used in lithium-ion batteries. The main component, the content is 0.06% to 0.5%. In Germany, NMP is classified as a third-level dangerous substance. If NMP is not recycled, it will not only cause environmental pollution, but also cause a lot of waste of raw materials. Therefore, recycling NMP is also an important part of the green battery production process that affects environmental protection. The existing NMP recovery methods mainly include freezing NMP solution recovery and rotary NMP solution recovery. [0003] The refrigeration type recovery method is to process all the waste gas containing NMP t...

AI Technical Summary

Problems solved by technology

[0003] The refrigeration recovery method is to process all the waste gas containing NMP through the adsorption and concentration wheel type. This method requires a huge investment in equipment, high energy consumption, low recovery efficiency, and high operating costs.

The rotary recovery method is gas-liquid mass transfer equipment (tower type) recovery. This method takes up a lot of space, requires a lot of maintenance (requires continuous water replenishment), and also has high energy consumption and high operating costs.

Images