Method for recovering nuclear matrix protein (NMP) solvent in production of lithium ion battery
The invention relates to a method for recovering a nuclear matrix protein (NMP) solvent in production of a lithium ion battery. The method comprises the following processing steps: (1) absorbing an NMP mixed gas by using a spray absorption tower, preparing an NMP mixed solution with high concentration, pumping and conveying the NMP mixed gas to the spray tower, and conveying NMP crude product liquid to a crude product tank; (2) rectifying and heating the NMP crude product liquid in vacuum to separate water from the NMP, wherein the recovered product is led to a mixing compartment to put into production via a pipeline, so that the NMP is used and recycled over and over again in a reciprocating manner. The water and the NMP are orderly separated in a gaseous form in a heating manner, and purified by in condensing and collecting manners, so as to achieve the target of recovering the product. 1. A lithium ion battery in the production process for the recovery of NMP solvent, which is characterized by comprising the following processing steps: (1), by using the spray absorbing tower to absorb the mixed gas NMP, systems containing high concentration of the mixed solution of NMP: the coated the absorption tower containing high concentration in NMP machine oven mixed gas will be drawn out through the exhaust fan is delivered to the spray tower, spray tower the NMP mixed gas in the deionized water of the spray tower to the gas-liquid contact absorption, the gas dissolved in the deionized water to become NMP mixed solution of NMP, as the mixed liquid to and from the circulation of the gas contained in the absorption of most of the NMP, when the NMP concentration is up to 60%-80% of the range, part of the high-concentration solution of NMP, NMP thick fluid is in the tank is delivered to the crude product; (2), the vacuum rectification thick fluid NMP: the crude product of high-concentration in the tank solution NMP using vacuum adsorption is delivered to the tank, the use of heat conducting oil to the kettle heating crude product NMP, produced stage of the heat-conducting oil temperature of about 160 ±5 °C, -off NMP stage temperature is about 150 ±5 °C, vessel is in a vacuum state when the temperature is raised to 50 the left and right [...] the form of moisture vapor to the first evaporation, through the circulation of water in the top of the tower is separated after condensation collected in the water tank; the decreased portion of the water to rise in the NMP solvent and, at this moment in the tower body is also correspondingly increase in temperature, the output gas is water steam and NMP mixture of two of the steam, in the same manner for condensing and collecting the same distill share pot , foreshot can be returned to the rectification column as a lower batch distillation of the raw material; the water content when the output object ≤ 300 PPM time, the kettle liquid is remaining in the finished product NMP, recovery of the vote of the workshop by the pipeline the introduction of adjuvants for producing, in the repeated use NMP reciprocating the repeated recycling, achieve the goal of recycling. 2. A lithium ion cell production method for recovering solvent NMP according to Claim 1, characterized in that the rectification of the vacuum degree in the autoclave, at least in -80KPa the above.