Dichloromethane gas condensation recovery device

Abstract

The utility model provides a dichloromethane gas condensation recovery device, which is used for recovering dichloromethane gas in a drying box and comprises a layering tank, a pipeline, two fans, at least one condenser and a heater, the pipeline is provided with a gas inlet end and a gas outlet end, the gas inlet end is communicated with the bottom of the drying box, and the gas outlet end is communicated with the top of the drying box and the tail gas recovery device; the two fans are respectively arranged at the gas inlet end and the gas outlet end and can be used for pumping dichloromethane gas in the drying box from the gas inlet end to the gas outlet end to form a gas flow path; at least one condenser and a heater are sequentially arranged on the pipeline in the advancing direction of the gas flow path, and the condenser is used for condensing part of dichloromethane gas in the pipeline into dichloromethane liquid and discharging the dichloromethane liquid into the flux tank; the heater is used for heating dichloromethane gas which passes through the condenser and is not condensed by the condenser. The dichloromethane recovery device can improve the recovery quality of dichloromethane and reduce the energy consumption of tail gas recovery equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion battery production, and more specifically to a dichloromethane gas condensation recovery device. Background Art

[0002] Due to the advantages of high voltage, high energy density, high safety, low self-discharge rate, etc., lithium-ion batteries have replaced traditional batteries and are used as mobile power sources for a large number of devices in electric vehicles, solar energy storage batteries, energy storage power stations, smart phones, laptops, etc. At the same time, people have higher and higher requirements for lithium-ion batteries, requiring lithium-ion batteries to have high capacity, high rate, high stability, high safety and high consistency.

[0003] The diaphragm is one of the key inner components in the structure of lithium batteries. Its main material is a porous polymer film. Its main functions are electronic insulation and ion conduction, that is, isolating the positive and negative electrodes to prevent short circuits, while allowing lithium ions in the electrolyte to pass through; it can also block current conduction through the closed-cell function when the battery is overheated. The performance of the diaphragm determines the interface structure and internal resistance of the battery. The stability, consistency and safety of the diaphragm have a decisive influence on the discharge rate, energy density, cycle life and safety of the lithium battery. At present, there are four technical routes for the production of diaphragms: dry single-pull, dry double-pull, wet synchronous and wet asynchronous. Among them, wet synchronous represents the highest level and development direction of the industry. Compared with dry diaphragms, wet diaphragms are better in material properties such as thickness uniformity, mechanical properties (tensile strength, puncture resistance), air permeability, physical and chemical properties (wettability, chemical stability, safety), etc., which is conducive to the absorption and retention of electrolytes and improves the charging, discharging and cycling capabilities of batteries, and is suitable for high-capacity batteries.

[0004] The wet process for preparing the diaphragm is based on polyethylene (PE) as the main material and paraffin oil (LP) as the diluent. Under high temperature and high pressure, shear mixing forms a homogeneous melt. After rapid cooling, PE crystals are precipitated and LP droplets are dispersed in it. Dichloromethane (MC) is used as the extractant. Through the extraction and drying process, the replacement of MC and LP, and air and MC occurs successively, and finally a PE microporous membrane is obtained. The extraction process mainly utilizes the characteristics of paraffin oil being soluble in dichloromethane and dichloromethane having a low boiling point to extract the white oil from the microporous structure of the film.

[0005] like Figure 1The drying box 100 shown, since the boiling point of dichloromethane is 39.8°C, the drying box 100 contains a hot roller 110. After contacting with the diaphragm 120 containing dichloromethane, the dichloromethane becomes gas. As the production continues, the gas will accumulate more and more. The tail of the commonly used drying box is connected to a pipeline with a fan to transport the dichloromethane gas to the tail gas recovery device outside the workshop for processing and recovery. Since the tail gas recovery device is generally shared by multiple production lines at the same time, the tail gas volume and concentration are large, the tail gas recovery equipment consumes a lot of energy, and it is not easy to meet the emission standards. At the same time, since the tail gas recovery device has a long route, it is inevitable that it will leak and easily lead to the introduction of moisture, which greatly increases the loss of dichloromethane and reduces the quality of recovered dichloromethane. Utility Model Content

[0006] 1. Technical issues to be resolved

[0007] The technical problem to be solved by the utility model is that the existing methylene chloride tail gas recovery device is generally shared by multiple production lines at the same time, the tail gas air volume and concentration are large, the tail gas recovery equipment consumes a lot of energy, and it is not easy to meet the emission standards. At the same time, due to the long route of the tail gas recovery device, it is inevitable to leak and easily lead to the introduction of moisture, which greatly increases the loss of methylene chloride and reduces the quality of recovered methylene chloride.

[0008] (II) Technical solution

[0009] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0010] The utility model provides a dichloromethane gas condensation recovery device, which is used for recovering the dichloromethane gas in a drying box, and comprises a stratification tank, a pipeline, two fans, at least one condenser and a heater; the pipeline has an air inlet end and an air outlet end, the air inlet end is connected to the bottom of the drying box, and the air outlet end is connected to the top of the drying box and an exhaust gas recovery device; the two fans are respectively arranged at the air inlet end and the air outlet end, and the fans can pump the dichloromethane gas in the drying box from the air inlet end to the air outlet end to form a gas flow path; at least one condenser and a heater are sequentially arranged on the pipeline along the traveling direction of the gas flow path, the condenser is used for condensing part of the dichloromethane gas in the pipeline into dichloromethane liquid, and discharging the dichloromethane liquid into the stratification tank; the heater is used for heating the dichloromethane gas that passes through the condenser and is not condensed by the condenser.

[0011] Preferably, the pipeline further includes at least one first branch pipe, and the first branch pipe connects the air inlet end with the drying box.

[0012] Preferably, a first gas valve is provided on the first branch pipe.

[0013] Preferably, the pipeline further includes at least one second branch pipe, and the second branch pipe connects the exhaust end and the drying box.

[0014] Preferably, a second gas valve is provided on the second branch pipe.

[0015] Preferably, the pipeline further includes a third branch pipe, and the third branch pipe connects the exhaust end with the exhaust gas recovery device.

[0016] Preferably, a third gas valve is provided on the third branch pipe.

[0017] Preferably, the temperature of the dichloromethane gas flowing out of the heater is in the range of 40°C to 50°C.

[0018] Preferably, there are two condensers.

[0019] Preferably, the condensate recovery device further comprises a liquid infusion pipeline, and the liquid infusion pipeline connects the condenser and the stratification tank.

[0020] (III) Beneficial effects

[0021] The above technical solution of the utility model has at least the following advantages:

[0022] The dichloromethane gas in the drying box flows into the pipeline, and a part of the dichloromethane gas is condensed by the condenser to form dichloromethane liquid, which is separated and recovered after being placed in the stratification tank for stratification; thereby reducing the total content of dichloromethane gas in the pipeline, reducing the content of dichloromethane gas flowing into the tail gas recovery device, and thus reducing the energy consumption of the tail gas recovery device. At the same time, the dichloromethane gas is recovered in the middle section of the pipeline, reducing the flow of dichloromethane gas, thereby reducing the probability of introducing new impurities during the flow process, thereby reducing the loss of dichloromethane and improving the recovery quality of dichloromethane. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a structural schematic diagram of a dichloromethane gas condensation recovery device provided in an embodiment of the utility model.

[0025] The reference numerals in the figures are:

[0026] 100, drying box; 110, hot roller; 120, diaphragm; 200, tail gas recovery device;

[0027] 1. Stratification tank; 2. Pipeline; 3. Fan; 4. Condenser; 5. Heater; 6. First gas valve; 7. Second gas valve; 8. Third gas valve; 9. Liquid infusion pipeline;

[0028] 21. Inlet end; 22. Exhaust end; 23. First branch pipe; 24. Second branch pipe; 25. Third branch pipe. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly located on the other element or indirectly located on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0031] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The following is a more detailed description of the specific implementation of the present utility model in conjunction with specific embodiments:

[0033] like Figure 1As shown, an embodiment of the utility model provides a dichloromethane gas condensation recovery device for recovering dichloromethane gas in a drying box 100, and the condensation recovery device comprises a stratification tank 1, a pipeline 2, two fans 3, at least one condenser 4 and a heater 5; the pipeline 2 has an air inlet end 21 and an exhaust end 22, the air inlet end 21 is connected to the bottom of the drying box 100, and the exhaust end 22 is connected to the top of the drying box 100 and the tail gas recovery device 200; the two fans 3 are respectively arranged at the air inlet end 21 and the exhaust end 22, and the fans 3 can pump the dichloromethane gas in the drying box 100 from the air inlet end 21 to the exhaust end 22 to form a gas flow path; at least one condenser 4 and a heater 5 are sequentially arranged on the pipeline 2 along the traveling direction of the gas flow path, and the condenser 4 is used to condense part of the dichloromethane gas in the pipeline 2 into dichloromethane liquid, and discharge the dichloromethane liquid into the stratification tank 1; the heater 5 is used to heat the dichloromethane gas that passes through the condenser 4 and is not condensed by the condenser 4. Specifically, the liquid discharged from the condenser 4 includes not only dichloromethane liquid but also waste water, etc.; since the dichloromethane liquid is an organic solvent, after the liquid discharged from the condenser 4 enters the stratification tank 1, a stratification phenomenon will occur after standing for a period of time, the dichloromethane liquid with a higher density is located at the lower floor, and the waste water with a lower density is located at the upper floor, and the waste water located at the upper floor flows into the wastewater treatment tank, and the dichloromethane liquid located at the lower floor enters the dichloromethane recovery tank, so as to realize the recovery of dichloromethane. It is difficult for the condenser 4 to ensure that all the dichloromethane gases in the pipeline can be condensed, and a part of the dichloromethane gas in the pipeline that passes through the condenser 4 and is not condensed by the condenser 4 flows into the heater 5, and the heater heats this part of the dichloromethane gas, and a part of this part of the dichloromethane gas flows back to the drying box 100 for balancing the wind pressure, and another part flows into the tail gas recovery device 200 for recovery. It should be noted that the tail gas recovery device 200 is a prior art well known to those skilled in the art, and will not be described in detail in this application. The tail gas recovery device 200 can recover dichloromethane gas. Specifically, in this embodiment, the condenser 4 is preferably filled with circulating chilled water at a temperature of about 7°C, and the circulating chilled water is Figure 1 The condenser 4 shown flows in from the bottom and flows out from the top, and the circulating chilled water exchanges heat with the dichloromethane gas at a higher temperature, so that the dichloromethane gas is condensed into dichloromethane liquid.

[0034] As one of the optional implementations of this embodiment, the pipeline 2 further includes at least one first branch pipe 23, and the first branch pipe 23 connects the air inlet end 21 and the drying box 100. In this embodiment, there are preferably two first branch pipes 23, and increasing the number of first branch pipes 23 can improve the efficiency of the intake of dichloromethane gas. At the same time, arranging multiple first branch pipes 23 at different positions of the bottom of the drying box 100 can realize the absorption of dichloromethane gas at different positions of the bottom of the drying box 100.

[0035] As one of the optional implementations of this embodiment, a first gas valve 6 is provided on the first branch pipe 23. The first gas valve 6 can control the on / off and flow rate of the gas in the first branch pipe 23, so as to facilitate real-time regulation of the state of the dichloromethane gas flowing into the pipeline 2.

[0036] As one of the optional implementations of this embodiment, the pipeline 2 further includes at least one second branch pipe 24, and the second branch pipe 24 connects the exhaust end 22 and the drying box 100. In this embodiment, there are preferably two second branch pipes 24. Increasing the number of second branch pipes 24 can improve the efficiency of exhausting dichloromethane gas. At the same time, arranging multiple second branch pipes 24 at different positions on the top of the drying box 100 can achieve balancing of wind pressure at different positions on the top of the drying box 100.

[0037] As one of the optional implementations of this embodiment, a second gas valve 7 is provided on the second branch pipe 24. The second gas valve 7 can control the on / off and flow rate of the gas in the second branch pipe 24, so as to facilitate real-time regulation of the state of the dichloromethane gas flowing out of the pipeline 2.

[0038] As one of the optional implementations of this embodiment, the pipeline 2 further includes a third branch pipe 25 , and the third branch pipe 25 connects the exhaust end 22 with the exhaust gas recovery device 200 .

[0039] As an optional implementation of this embodiment, a third gas valve 8 is provided on the third branch pipe 25 .

[0040] As one of the optional implementations of this embodiment, the temperature range of the dichloromethane gas flowing out of the heater 5 is 40° C.-50° C.

[0041] As one of the optional implementations of this embodiment, there are two condensers 4. Increasing the number of condensers 4 can improve the condensation efficiency of dichloromethane gas.

[0042] As one of the optional implementations of this embodiment, the condensation recovery device also includes a liquid infusion pipeline 9, which connects the condenser 4 and the stratification tank 1.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dichloromethane gas condensation recovery device, used to recover dichloromethane gas in a drying oven, characterized in that: The invention comprises a stratification tank, a pipeline, two fans, at least one condenser and a heater; the pipeline has an air inlet end and an air outlet end, the air inlet end is connected to the bottom of the drying box, and the air outlet end is connected to the top of the drying box and an exhaust gas recovery device; the two fans are respectively arranged at the air inlet end and the air outlet end, and the fans can pump the dichloromethane gas in the drying box from the air inlet end to the air outlet end to form a gas flow path; at least one condenser and a heater are sequentially arranged on the pipeline along the traveling direction of the gas flow path, the condenser is used to condense part of the dichloromethane gas in the pipeline into dichloromethane liquid, and discharge the dichloromethane liquid into the stratification tank; the heater is used to heat the dichloromethane gas that passes through the condenser but is not condensed by the condenser.

2. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: The pipeline further includes at least one first branch pipe, and the first branch pipe is connected with the air inlet end and the drying box.

3. The dichloromethane gas condensation recovery device according to claim 2, characterized in that: The first branch pipe is provided with a first gas valve.

4. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: The pipeline further includes at least one second branch pipe, and the second branch pipe is connected with the exhaust end and the drying box.

5. The dichloromethane gas condensation recovery device according to claim 4, characterized in that: The second branch pipe is provided with a second gas valve.

6. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: The pipeline also includes a third branch pipe, and the third branch pipe is connected with the exhaust end and the exhaust gas recovery device.

7. The dichloromethane gas condensation recovery device according to claim 6, characterized in that: The third branch pipe is provided with a third gas valve.

8. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: The temperature of the dichloromethane gas flowing out of the heater is in the range of 40°C to 50°C.

9. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: There are two condensers.

10. The dichloromethane gas condensation recovery device according to claim 1, characterized in that: The condensation recovery device also includes a liquid infusion pipeline, which connects the condenser and the stratification tank.

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