NMP Solvent Processing System Waste Gas Treatment Equipment for Lithium Cell Making

Chapter I Equipment Introduction

1、NMP Working principle of recovery system

NMP recovery system uses the physical characteristics of NMP and adopts multi-stage condensation to fully condense and realize recovery. The temperature of the waste gas discharged from the coater is about 120 ℃. The temperature can be reduced to about 25 ℃ through the recovery system, which can cool and recover more than 95% of NMP.

2、System characteristics

2.1、The effect is good, and the solvent recovery can reach more than 95%; The purity of recovered NMP waste liquid reaches more than 80%;

2.2、Energy saving. The energy consumption of the system itself is only 4.0kw/h (taking 50000m3/h air volume and air duct length less than 20m as an example). So far, it is the equipment with the lowest power consumption in all NMP recovery systems, and the product is recommended by the national environmental protection department;

2.3、Long term stability: the NMP recovery system produced by our company can ensure that its performance (recovery rate, recovery concentration) will not be reduced within 3 years, and its stability will reach the best state;

2.4、The safety performance is good. The equipment has special fault handling settings. Even if there is a sudden fault, there will be no backflow, suffocation and other accidents that affect the normal operation of the coater.

 

3、Technical requirement

Item	Unit	Specification
1)Exhaust air volume	m3/h	50000（Exhaust air volume of coater）
2)Air outlet temperature	℃	120℃
3) NMP consumption	kg/h	Above 45
2、NMP Technical requirements for recycling
1)rate of recovery		≥95%
2) Recovery concentration		≥80%
3) NMP exhaust emission concentration after recovery	PPM	Below 200
3、Material of auxiliary facilities
1)Ventilation duct		White iron pipe 300mmx300mmx0.0.6mm

 

4、Process performance requirements

SN	Item	Specification
1	Energy saving performance	Use tube fin heat exchanger to save energy consumption.
2	Sealing performance	All connections in the unit are sealed with high-temperature silica gel and high-temperature glue. The air leakage rate at the connection of each functional section is less than 0.5%.
3	Linkage performance	Linked with the coater separately, the unit can operate under the best working conditions, and the recovered NMP concentration is more stable.
4	Others	After the equipment stops running, NMP cannot flow back to the air inlet pipe, and when the NMP recovery system fails, it will not affect the use of the coater.

Chapter II System Design

1、Design parameters

Exhaust temperature：120℃

Treatment air volume：50000m3/h

Rate of recovery：≥95%

Concentration of recovered waste liquid：≥ 80%

Exhaust emission concentration：Below 200 ppm

2、Technological process

The process flow chart is as follows:

 

3、Process description

3.1、Heat exchange treatment

The temperature from the coater is about 120 ℃. After heat exchange, the waste gas of about 100 ℃ enters the NMP condenser to realize condensation and recovery of NMP.

3.2、Equipment size

The size of the main retractor is：2200mm x 1650mm x 2100mm （L*W*H）；

Size of cooling water tower：Base diameter：1200mm, Height：1900mm；  

Reservoir size：1400mm x 1200mm x6000mm(L*W*H）

(Note: subject to actual production); The total weight is about 1.2 tons, and the operating weight is about 3.0 tons.

The air duct of the recovery equipment adopts white iron leather pipe with the size of：300mm x300mm x 0.6mm（Thickness）。The connection between the pipe section and the pipe section is sealed with high-temperature silica gel.

PPR pipe is adopted for water pipe。

3.4、Layout plan of recycling system

3.5、Recovery process pipeline diagram

3.6 Air duct installation layout diagram

 

4、Main equipment of the system

SN	Organization name	Part name	Material	Specification	Manufacturer
1	Cooling solvent recovery section (condenser)	Cooling coil 1	Aluminum wing & copper tube	XYZ-500-6	TMAX
2		Cooling coil 2	Aluminum wing & copper tube	XYZ-500-8	TMAX
3					TMAX
4					TMAX
5		Liquid blocking plate	Corrosion resistant stainless steel		TMAX
6		Effusion disk	Corrosion resistant stainless steel		TMAX
7		Recovery tank	Corrosion resistant stainless steel		TMAX
8		Liquid level pump	Anticorrosive materials		Xiaoyezi
9	Forced draft fan section	Manual air valve	Anticorrosive materials		Xiaoyezi
10		Centrifugal fan	Anticorrosive materials	7KW	Xinfeng
11	Water cooling circulation section	cooling tower		20T	Liangyuan
12		water circulating pump		2P	Chinese Trumpet Vine
13

 

 

5、Electrical design

5.1 electrical part (function and implementation mode)

Schneider air switch, AC contactor and thermal relay are adopted; Electric regulating air valve; Chint phase sequence protection relay and time relay.

5.2 Safety Control

(1) Design automatic control system and interlocking system, equipped with temperature alarm.

(2) NMP waste liquid transmission adopts the intelligent mode of liquid level detection and alarm. The liquid storage tank is placed on the roof, and the anti-corrosion aluminum-plastic pipe is connected to the place designated by the customer. The liquid level detection is used in the liquid storage tank, and the alarm is realized when the liquid level reaches the specified height. The alarm small electric box device is placed at the head position of the coater and the waste liquid filling position respectively, and then the waste liquid on the roof is transported to the downstairs filling barrel through the manual valve at the filling position.