阅读说明：本技术 一种气体浓缩装置、有机溶剂回收系统及有机气体回收浓缩方法 (Gas concentration device, organic solvent recovery system and organic gas recovery and concentration method ) 是由 金伟力 于 2021-08-13 设计创作，主要内容包括：本发明涉及一种有机气体浓缩装置、有机溶剂回收系统及有机气体回收浓缩方法,所述有机气体浓缩装置的吸附转子包括吸附区、再生区和冷却区；所述吸附区包括两个以上子吸附区,所述两个以上子吸附区依次连通,待处理气体依次通过所述子吸附区进行多区域逐级净化吸附以使尾气接近零排放；所述有机溶剂回收系统将热交换、冷凝回收与吸附浓缩相结合,其中所述热交换采用多级热交换,适用于从生产设备排出的含有有机溶剂的高温尾气与返回生产设备回收了有机溶剂之后的低温尾气之间进行热交换。本发明不仅大大提高了有机溶剂的回收率、增加经济效益,而且减少了排放到环境中的有机污染物,达到经济、高效处理生产设备有机溶剂污染尾气的目的。(The invention relates to an organic gas concentration device, an organic solvent recovery system and an organic gas recovery concentration method, wherein an adsorption rotor of the organic gas concentration device comprises an adsorption area, a regeneration area and a cooling area; the adsorption zone comprises more than two sub-adsorption zones, the sub-adsorption zones are sequentially communicated, and gas to be treated sequentially passes through the sub-adsorption zones to be subjected to multi-zone step-by-step purification adsorption so as to enable tail gas to be nearly zero-discharged; the organic solvent recovery system combines heat exchange, condensation recovery and adsorption concentration, wherein the heat exchange adopts multi-stage heat exchange and is suitable for heat exchange between high-temperature tail gas containing the organic solvent and discharged from production equipment and low-temperature tail gas after the organic solvent is returned to the production equipment and recovered. The invention not only greatly improves the recovery rate of the organic solvent and increases the economic benefit, but also reduces the organic pollutants discharged into the environment, thereby achieving the purpose of economically and efficiently treating the tail gas polluted by the organic solvent of the production equipment.)

1. A gas concentrator device, comprising:

an adsorption rotor;

a central shaft around which the adsorption rotor rotates;

the method is characterized in that: the adsorption rotor comprises an adsorption zone, a regeneration zone and a cooling zone; the adsorption zone comprises more than two sub-adsorption zones, the sub-adsorption zones are sequentially communicated, and gas to be recovered sequentially passes through the sub-adsorption zones to perform multi-zone step-by-step purification adsorption so as to enable tail gas to reach the emission standard; the cooling zone receives air from the outside or the gas to be recovered to cool the adsorption rotor; the regeneration zone is used for desorbing and concentrating the organic solvent adsorbed on the adsorption rotor in a heating regeneration mode.

2. The gas concentrator of claim 1, wherein: the heating regeneration mode comprises a mode of heating by using a regenerative heater or a mode of directly using the heated outside air or the gas to be recovered after passing through a cooling area for heating desorption.

3. The gas concentrator of claim 2, wherein: and the outside air or the gas to be recovered after passing through the cooling area is heated and then is secondarily heated by the regenerative heater to be used as the regenerative gas to be sent into the regeneration area.

4. The gas concentrator of claim 1, wherein: the number of sub-adsorption zones is 2, and the sub-adsorption zones are respectively a first sub-adsorption zone and a second sub-adsorption zone, and the area of the first sub-adsorption zone is larger than that of the second sub-adsorption zone.

5. The gas concentrator of claim 4, wherein: the adsorption rotor is divided into a first sub-adsorption area, a regeneration area, a cooling area and a second sub-adsorption area in sequence in the rotating direction of the rotating wheel.

6. An organic solvent recovery system combining adsorption concentration and condensation for recovering an organic solvent from an organic solvent-containing tail gas discharged from a production apparatus, comprising: a heat exchange module, an organic solvent condensation recovery apparatus, and a gas concentration apparatus according to any one of claims 1 to 5;

the heat exchange assembly comprises at least one heat exchanger, and the heat exchanger exchanges heat between high-temperature tail gas containing the organic solvent discharged from the production equipment and low-temperature tail gas after the organic solvent is returned to the production equipment and recovered;

an organic solvent condensation recovery device for condensing the gas from the heat exchange unit and the regeneration gas concentrated by the gas recovery and concentration device to recover the organic solvent;

the gas concentration device carries out adsorption recovery and concentration regeneration step by step on the residual organic solvent gas passing through the organic solvent condensation recovery device, the residual low-temperature tail gas after adsorption is partially discharged, and part of the residual low-temperature tail gas is returned to the production device after heat exchange by the heat exchange assembly.

7. The organic solvent recovery system of claim 6, wherein: the heat exchange assembly comprises at least two heat exchangers, and reverse cascade heat exchange is carried out between high-temperature gas containing the organic solvent discharged from the production equipment and low-temperature tail gas after the organic solvent is returned to the production equipment through the two heat exchangers at least.

8. The organic solvent recovery system of claim 6, wherein: the organic solvent condensing and recycling device comprises at least two of a normal-temperature water cooler, a cooling water condenser, a heat pipe and a direct expansion pipe.

9. An organic gas concentration method is characterized by comprising the following steps:

i) step (2) of purifying and adsorbing organic gas in a multi-zone of an adsorption rotor step by step so as to enable the treated low-temperature tail gas to reach the emission standard;

ii) a step of subjecting the adsorption medium to regenerative heating to produce a regenerated concentrated organic gas;

iii) a step of cooling the adsorption medium.

10. The method for recovering and concentrating the organic solvent is characterized by comprising the following steps of:

i) a step of heat recovery of high-temperature tail gas containing an organic solvent discharged from production equipment;

ii) a step of condensing the tail gas after heat recovery to recover a large amount of the target organic solvent;

iii) purifying and adsorbing the condensed tail gas in a multi-zone stage by stage of an adsorption rotor so as to enable the treated low-temperature tail gas to reach the emission standard;

iv) carrying out regenerative heating desorption on the gas of the organic solvent adsorbed in the adsorption rotor in the multi-zone step-by-step purification adsorption process to generate regenerative concentrated organic solvent gas;

v) a step of secondary condensation and recovery of the regenerated concentrated organic solvent gas;

vi) carrying out heat exchange on the low-temperature tail gas subjected to multi-zone stepwise purification and adsorption and the heat generated by heat recovery in the step i) to generate high-temperature gas for returning to production equipment.

11. The method for recovering and concentrating an organic solvent according to claim 10, wherein: said heat recovery in step i) and heat exchange in step vi) comprises at least two stages of heat recovery and heat exchange steps.

12. The method for recovering and concentrating an organic solvent according to claim 10, wherein: said condensation treatment in said step ii) comprises at least two condensation treatment steps.

Technical Field

The invention relates to a system and a method for recovering an organic solvent and purifying Volatile Organic Compounds (VOCs) polluted gas, in particular to a system and a method for recovering the organic solvent by combining adsorption concentration and condensation.

Background

Organic solvents used in some production processes (such as semiconductor manufacturing, lithium ion battery production processes, etc.) volatilize to the surrounding environment in the production process, which not only causes pollution of the environmental air, but also causes the product manufacturing cost to be greatly increased because some organic solvents are expensive and are directly discharged to the environment, so that the organic solvent recovery method adopted for recovering the organic solvents with economic efficiency is an important subject of attention.

The recovery method of the organic solvent in the exhaust gas discharged by the general production equipment comprises a condensation recovery method, an adsorption separation method and an absorption separation method (for the water-soluble organic solvent, the method is also called a water washing method). The condensation recovery method is to directly cool the tail gas containing the organic solvent, to reduce the temperature of the tail gas below the dew point of the organic solvent, and to condense the organic solvent contained in the tail gas into liquid for recovery. The adsorption separation method is that an adsorbent is adopted to adsorb the organic solvent in the tail gas containing the organic solvent to separate the organic solvent from the tail gas, then the organic solvent adsorbed in the adsorbent is desorbed through desorption operation, and then the organic solvent is recovered through condensation operation. The absorption and separation method is to absorb the organic solvent in the tail gas by using absorption liquid to separate the organic solvent from the tail gas, and then separate the organic solvent from the absorption liquid by methods such as distillation and the like to obtain the organic solvent. At present, for some tail gas with large air volume and low concentration and containing organic solvent, a method combining separation and concentration by an adsorption rotor and condensation is generally adopted. The concentration of the organic solvent in the gas at the outlet of the adsorption zone of the general adsorption rotor can be reduced to below 10ppm, although the environmental emission standard is met. However, the air volume of the tail gas discharged in the general production process is very large, such as drying in a 4Gwh/Y lithium ion battery factoryThe total air quantity of the project can reach 3500Nm³And/min. Even if the concentration of NMP, an organic solvent, in the gas discharged after adsorption purification, is only 10ppm, if the production apparatus is continuously operated for 8520 hours (355 days, 24 hours/day) per year, the total amount of NMP to be discharged into the atmosphere per year can reach about 79 tons. Not only causes the waste of raw and auxiliary material resources, but also has adverse effect on the environment. Therefore, further reducing the concentration of the organic solvent in the exhaust gas discharged to the atmosphere becomes a new problem of reducing the production cost and reducing the environmental pollution.

In order to solve the above-mentioned problems, a method has been proposed in which a two-stage adsorption apparatus is used in series (japanese laid-open patent publication JP 2014-521A), and in order to improve the purification rate and reduce the concentration of an organic solvent in exhaust gas, two-stage adsorption is adopted, and a gas to be treated is subjected to adsorption purification by a first adsorbent, and then sent to a second adsorbent to be further subjected to adsorption purification, and the gas is discharged into the atmosphere after reaching the design required exhaust concentration. Although this method can reduce the concentration of the organic solvent in the exhaust gas discharged into the atmosphere to a desired low concentration, it is not a preferable solution because of the use of two-stage adsorption purification devices, which inevitably leads to problems such as high investment in system equipment, large floor space, and complicated system operation.

Disclosure of Invention

In view of the fact that the prior art can not meet the requirements of low equipment investment and high purification rate of the discharged tail gas at the same time, the invention mainly aims to provide an organic solvent recovery system which meets the requirements of customers and markets and adopts the combination of adsorption concentration and condensation.

In order to achieve the above object, a first aspect of the present invention provides a gas recovery and concentration device, including: an adsorption rotor; a central shaft around which the adsorption rotor rotates; the adsorption rotor comprises an adsorption zone, a regeneration zone and a cooling zone; the adsorption zone comprises more than two sub-adsorption zones, the sub-adsorption zones are sequentially communicated, and gas to be recovered sequentially passes through the sub-adsorption zones to perform multi-zone step-by-step purification adsorption so as to enable tail gas to reach the emission standard; the cooling zone receives air from the outside or the gas to be recovered to cool the adsorption rotor; the regeneration zone is used for desorbing and concentrating the organic solvent adsorbed on the adsorption rotor in a heating regeneration mode.

Further, the heating regeneration mode includes a mode of heating by using a regenerative heater or a mode of directly using the heated outside air or the gas to be recovered after passing through a cooling zone for heating desorption.

Furthermore, the outside air or the gas to be recovered after passing through the cooling zone is heated by the regeneration heater and then is sent to the regeneration zone as the regeneration gas.

Preferably, the number of the sub-adsorption regions is 2, the sub-adsorption regions are respectively a first sub-adsorption region and a second sub-adsorption region, and the area of the first sub-adsorption region is larger than that of the second sub-adsorption region.

Optionally, the adsorption rotor is sequentially divided into a first sub-adsorption region, a regeneration region, a cooling region and a second sub-adsorption region in the rotation direction of the rotating wheel.

The second aspect of the present invention provides an organic solvent recovery system using a combination of adsorption concentration and condensation for recovering an organic solvent from an organic solvent-containing off-gas discharged from a production apparatus, comprising: the heat exchange component, the organic solvent condensation recovery device and the gas recovery and concentration device are arranged on the heat exchange component; the heat exchange assembly comprises at least one heat exchanger, and the heat exchanger exchanges heat between high-temperature tail gas containing the organic solvent discharged from the production equipment and low-temperature tail gas after the organic solvent is returned to the production equipment and recovered; an organic solvent condensation recovery device for condensing the gas from the heat exchange unit and the regeneration gas concentrated by the gas recovery and concentration device to recover the organic solvent; the gas recovery and concentration device is used for carrying out adsorption recovery and concentration regeneration on the residual organic solvent gas passing through the organic solvent condensation and recovery device step by step, the residual low-temperature tail gas after adsorption is partially discharged, and part of the residual low-temperature tail gas is returned to the production device after heat exchange by the heat exchange assembly.

Preferably, the heat exchange assembly comprises at least two heat exchangers, and reverse step heat exchange is carried out between high-temperature gas containing the organic solvent discharged from the production equipment and low-temperature tail gas returned to the production equipment after the organic solvent is recovered through at least two stages of heat exchangers.

Further, the organic solvent condensation and recovery device comprises at least two of a normal-temperature water cooler, a cooling water condenser, a heat pipe and a direct expansion pipe.

The third aspect of the present invention also provides an organic gas concentration method, characterized by comprising the steps of:

i) step (2) of purifying and adsorbing organic gas in a multi-zone of an adsorption rotor step by step so as to enable the treated low-temperature tail gas to reach the emission standard;

ii) a step of subjecting the adsorbent to regenerative heating to produce a regenerated concentrated organic gas;

iii) a step of cooling the adsorbent.

In addition, the fourth aspect of the present invention further provides an organic solvent recovery and concentration method, characterized by comprising the steps of:

i) a step of heat recovery of high-temperature tail gas containing an organic solvent discharged from production equipment;

ii) a step of condensing the tail gas after heat recovery to recover a large amount of the target organic solvent;

iii) purifying and adsorbing the condensed tail gas in a multi-zone stage by stage of an adsorption rotor so as to enable the treated low-temperature tail gas to reach the emission standard;

iv) regenerating, heating and desorbing the organic solvent adsorbed in the adsorption rotor in the multi-zone step-by-step purification and adsorption process to generate regenerated and concentrated organic solvent gas;

v) a step of secondary condensation and recovery of the regenerated concentrated organic solvent gas;

vi) carrying out heat exchange on the low-temperature tail gas subjected to multi-zone stepwise purification and adsorption and the heat generated by heat recovery in the step i) to generate high-temperature gas for returning to production equipment.

Preferably, said heat recovery in step i) and heat exchange in step vi) comprise at least two stages of heat recovery and heat exchange steps.

Optionally, said condensation treatment in step ii) comprises at least a two-stage condensation treatment step.

Based on the design, the invention has the beneficial effects that: arranging a plurality of adsorption zones, preferably two adsorption zones, above one adsorption rotor, wherein the first sub-adsorption zone is used for adsorbing organic solvent in a part of tail gas containing organic solvent and needing to be discharged out of the system from the production device; the second sub-adsorption area is used for further adsorbing and purifying the organic solvent in the tail gas which is adsorbed by the first sub-adsorption area and needs to be discharged out of the system, so that the zero emission of the organic solvent in the discharged tail gas is approximate. In addition, a cascade serial heat exchange mode is adopted, so that heat exchange is carried out between high-temperature tail gas containing the organic solvent discharged from production equipment and low-temperature tail gas returned to the production equipment after the organic solvent is recovered through at least two stages of heat exchangers, the temperature of gas returned to the production equipment is greatly increased, and organic combination of energy conservation, environmental protection and economic benefit is realized.

Drawings

Fig. 1 is a schematic front surface view of an adsorption rotor in a preferred embodiment of the gas concentration apparatus of the present invention.

FIG. 2 is a schematic view of the flow configuration of the preferred embodiment of the organic solvent recovery system of the present invention.

In fig. 1-2:

100. production equipment; 200. a heat exchanger; 210. a first stage heat exchanger; 220. a second stage heat exchanger; 300. a solvent condensing and recovering device; 310. a cooler; 320. a condenser; 330, a recovery storage tank; 400. an adsorption rotor; 410. a first sub-adsorption zone; 420. a second sub-adsorption zone; 430. a cooling zone; 440. a regeneration zone; 500. a regenerative heater; 600. a treated gas fan; 700. a regeneration gas fan.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments shown in the drawings. It should be noted that these embodiments are not intended to limit the present invention, and those skilled in the art should be able to make functional, methodical, or structural equivalents or substitutions according to these embodiments without departing from the scope of the present invention.

Meanwhile, in the present specification, descriptions related to orientations such as up, down, left, right, front, rear, inner, outer, longitudinal, lateral, vertical, horizontal, etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present specification, unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are used broadly and may be, for example, fixedly, detachably, or integrally connected, mechanically or electrically connected, directly or indirectly connected through an intermediate medium, or communicated between two elements. To those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations, and the present invention should not be construed as being limited thereto.

Fig. 1 shows a preferred embodiment of the adsorption rotor of the present invention, which is configured to adsorb, recover and concentrate organic solvents contained in the offgas discharged to the outside of the system by using the adsorption rotor 400. When the adsorption rotor 400 is running, it is driven by a driving motor (not shown in the figure) to rotate around the central shaft, and is divided into a first sub-adsorption zone 410, a regeneration zone 440, a cooling zone 430, and a second sub-adsorption zone 420 in turn by a wheel frame, a bracket, and a sealing material (not shown in the figure) in the rotation direction, that is, the adsorption material carried by the adsorption rotor 400 passes through the first sub-adsorption zone 410, the regeneration zone 440, the cooling zone 430, and the second sub-adsorption zone 420 in turn during operation, and the area of the first sub-adsorption zone is larger than that of the second sub-adsorption zone, so that a part of the exhaust gas containing organic solvent, which is required to be exhausted out of the system from the production apparatus in a relatively high concentration state, can pass through the first sub-adsorption zone at a relatively low wind speed, on the other hand, the area of the second sub-adsorption zone is small, so as to increase the flow speed of the treated gas in a relatively low concentration to increase the probability of collision with the surface of the adsorption rotor gas channel, thereby achieving the purpose of improving the adsorption and purification efficiency; the adsorbent supported by the adsorption rotor depends on the organic solvent to be adsorbed, and the adsorption material is generally but not limited to hydrophobic molecular sieve, and the hydrophobic molecular sieve generally refers to molecular sieve with silicon-aluminum ratio Si/Al more than 20, such as ZSM-5 type molecular sieve, Y type molecular sieve and the like. In a preferred embodiment of the present invention, the gas to be recovered or the external air may be used, and preferably, the gas to be recovered is used as a cooling gas to cool the adsorption rotor, and the cooling gas is heated by the cooling zone and then directly heats, desorbs and concentrates the regeneration zone, when the desorption and desorption efficiency is reduced due to a low temperature, the cooling gas heated by heat exchange in the cooling zone may be heated again to the regeneration temperature by the regeneration heater 500 and then sent to the regeneration zone, or directly heated by the regeneration heater to generate a concentrated organic gas, and the heating source of the regeneration heater 500 is preferably high-temperature hot oil, high-temperature water vapor, or electric heating.

In addition, it should be understood that although the number of the sub-adsorption regions is two and the shape of the adsorption rotor is a circle in the present embodiment, the number and the shape should not be construed as limiting the scope of the claims, and those skilled in the art can select any number of sub-adsorption regions and design the shape of the adsorption rotor with any shape according to the requirements of the exhaust emission standard.

Fig. 2 shows a preferred embodiment of the organic solvent recovery system according to the present invention, which is specifically an organic solvent recovery system combining adsorption concentration and condensation, for recovering an organic solvent from an organic solvent-containing tail gas discharged from a production apparatus, as shown in fig. 2, the recovery system comprising: the production equipment 100, the heat exchange assembly, the organic solvent condensation and recovery device, the adsorption rotor and the matched structure thereof are adopted; the heat exchange assembly comprises at least one heat exchanger, and in order to further improve the heat exchange performance in practical production, two heat exchangers are preferably adopted, namely: a first stage heat exchanger 210 and a second stage heat exchanger 220; the organic solvent condensation and recovery device comprises a cooler 310, a condenser 320 and a recovery storage tank 330; the adsorption rotor and its matching structure include the adsorption rotor 400, the regenerative heater 500, the treated gas fan 600, and the regenerated gas fan 700. The system is used for recovering the organic solvent in the tail gas containing the organic solvent discharged by the production equipment. The source of the tail gas of the production equipment containing the organic solvent can be, but is not limited to, the exhaust air of the lithium ion battery positive pole coating machine oven, and the contained organic solvent can be, but is not limited to, an organic solvent such as N-methylpyrrolidone (NMP) or a volatile organic compound.

It should be understood that, although the number of the heat exchangers used in the present embodiment is two and the condensate recovery device selects the matching between the cooler and the condenser, it should not be construed as limiting the scope of the claims, and one skilled in the art may select at least one heat exchanger according to the requirement of the actual heat exchange performance and select at least two of the normal temperature water cooler, the cooling water condenser, the heat pipe, and the direct expansion pipe as the combination of the condensate recovery device.

In this embodiment, the first-stage heat exchanger 210 and the second-stage heat exchanger 220 perform reverse cascade heat exchange between the high-temperature tail gas containing the organic solvent discharged from the production facility and the low-temperature tail gas after returning to the production facility and recovering the organic solvent, thereby cooling the tail gas containing the high-concentration organic solvent, which has a temperature of 100 ℃ or higher from the production facility 100, to a normal temperature state (typically, a temperature of about 30 to 40 ℃), and heating the low-temperature tail gas (typically, a temperature of less than 15 ℃) which has returned to the production facility 100 from the outlet of the condenser 320 and has recovered the organic solvent to 75 ℃ or higher. The organic solvent condensation and recovery device condenses the gas from the heat exchange assembly and the regeneration gas concentrated by the gas recovery and concentration device to recover the organic solvent, wherein the cooler 310 further cools the tail gas from the second-stage heat exchanger 220 by cooling water from a cooling water tower at a temperature of about 30 ℃, and the condenser 320 cools the tail gas from the cooler 310 by low-temperature cold water (usually at a temperature of less than 12 ℃) from a freezer to condense the organic solvent in the tail gas into liquid for recovery. The gas recovery and concentration device is used for gradually adsorbing and recovering the residual organic solvent gas after passing through the organic solvent condensation and recovery device, the residual low-temperature tail gas after adsorption is partially discharged, and part of the residual low-temperature tail gas is returned to the production device 100 after heat exchange by the heat exchange assembly. The treated gas fan 600 is used for sequentially blowing the treated gas to the first adsorption area 410 of the adsorption rotor 400, sending the treated gas primarily purified by the first sub-adsorption area 410 to the second adsorption area 420, adsorbing and removing almost all organic solvents contained in the tail gas after two times of adsorption and purification by the adsorption rotor 400, and discharging the purified gas to the outside of the system; the regeneration fan 700 blows the regeneration gas heated to a predetermined temperature by the regeneration heater 500 to the regeneration zone 440 of the adsorption rotor 400 from the regeneration zone inlet, blows the regeneration gas desorbed from the organic solvent adsorbed in the adsorption rotor 400 to the inlet of the cooler 310, mixes the regeneration gas with the high-concentration organic solvent-containing tail gas cooled by the low-temperature tail gas returned to the production facility 100 after the organic solvent is recovered by the second-stage heat exchanger 220, and introduces the mixture into the cooler 310, and further condenses and recovers the mixture by the condenser 320.

In the design for the present preferred embodiment, as shown in fig. 2, the air volume of the organic solvent-containing off-gas a from the production apparatus 100 is 110,000Nm³H, temperature 100 ℃, concentration of N-methylpyrrolidone (NMP) as organic solvent 2279ppm, tail gas b which is heat-exchanged with tail gas h having a temperature of about 50.5 ℃ from the outlet of the second heat exchanger 220 and then has a temperature reduced to 70.3 ℃ enters the second heat exchanger 220, and is mixed with tail gas g (air volume 99,500 Nm/m) returned from the outlet of the condenser 320³H, the temperature is 12 ℃) and the temperature is reduced to 35.3 ℃ after heat exchange, and the tail gas c with the temperature of 35.3 ℃ and the regeneration outlet gas s led out from the regeneration zone 440 of the adsorption rotor 400 through the regeneration fan 700 are mutually connectedMixed gas d (air quantity 111,500 Nm)³H, the temperature is 35.6 ℃, the NMP concentration is 2278 ppm) sequentially enter the cooler 310 and the condenser 320, the gas f at the outlet of the condenser 320 is cooled to 12 ℃, the vast majority of the contained organic solvent NMP is condensed into liquid and enters the recovery storage tank 330, and the vast majority of the tail gas g at the outlet of the condenser 320 is returned to the low-temperature side inlet of the second-stage heat exchanger 220. On the other hand, a small portion of the off-gas l to be discharged to the outside of the system is sent to the first sub-adsorption zone 410 of the adsorption rotor 400, most of the organic solvent contained in the off-gas is adsorbed in the adsorption rotor 400 by the adsorption action of the adsorbent in the adsorption rotor 400, the off-gas passing through the first sub-adsorption zone 410 is sent to the second sub-adsorption zone 420, almost all of the organic solvent contained in the off-gas is adsorbed by the adsorption rotor 400, the NMP concentration in the off-gas at the outlet of the second sub-adsorption zone 420 is reduced to 1ppm or less, and the purified off-gas o is discharged to the atmosphere. The same tail gas p is introduced into the cooling zone 430 of the adsorption rotor 400 as the inlet of the first sub-adsorption zone 410, the temperature of the tail gas q at the outlet of the cooling zone 430 rises to 170 ℃ or higher, the tail gas q is sent into the regenerative heater 500 to be heated to 200 ℃ and then sent into the regeneration zone 440 of the adsorption rotor 400 as the regeneration gas r, the organic solvent adsorbed in the rotating wheel is desorbed at high temperature, the concentration of NMP in the gas s at the outlet of the regeneration zone 440 reaches 2250ppm, the temperature is about 60 ℃, and the gas is mixed with the tail gas c at the outlet of the second-stage heat exchanger 220 and then sent into the high-temperature inlet side of the cooler 310. From the above design results, it can be seen that: the system can reduce the concentration of organic solvent in the part of tail gas to be discharged into the atmosphere to about 1ppm, and the temperature of the tail gas returned to the production equipment 100 can reach more than 80 ℃.

Compared with the existing serial solvent recovery system adopting two adsorption devices, the preferred embodiment of the invention only uses one adsorption rotor, realizes high purification rate under the condition of not increasing equipment investment, not only obviously reduces the concentration of the organic solvent discharged into the atmosphere and reduces environmental pollution, but also increases the recovery rate of the organic solvent and reduces production cost, and improves the temperature of tail gas returned to production equipment and realizes energy conservation due to the adoption of a two-stage heat exchange reverse step heat exchange mode. In particular to the tail gas treatment and organic solvent recovery process in the production process using expensive organic solvent, such as the lithium ion battery manufacturing.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical core and the spirit of the skilled artisan should be included in the scope of the present invention.