Organic waste gas treatment equipment based on nitrogen cyclic desorption

Abstract

The utility model discloses organic waste gas treatment equipment based on nitrogen circulating desorption, which belongs to the field of waste gas treatment and comprises an adsorption and desorption tower, an adsorption system, a desorption system and an outer cavity temperature control system, the adsorption and desorption tower is of a double-layer structure with an inner cavity and an outer cavity which are independent from each other, and an adsorbent is arranged in the inner cavity; the adsorption system is used for enabling waste gas to flow through an adsorbent, the desorption system is used for performing nitrogen circulation desorption on the saturated adsorbent, and the outer cavity temperature control system is used for regulating and controlling the temperature of the outer cavity. The outer cavity temperature control system is arranged in the inner cavity, so that the outer cavity can be heated through the outer cavity temperature control system when nitrogen circular desorption is performed, the adsorbent in the inner cavity can be maintained at the required temperature, and the outer cavity can be cooled after desorption is finished.

Description

Technical Field

[0001] The utility model relates to the field of waste gas treatment, and particularly relates to an organic waste gas treatment device based on nitrogen circulation desorption. Background Art

[0002] Currently, organic solvents are needed in many industries, and volatile organic compound (VOCs) waste gas will be generated. For example, various enterprises such as furniture manufacturing, metal processing, automobile production and maintenance, and biochemistry.

[0003] There are also many processes and supporting equipment available for the treatment of volatile organic compound (VOCs) waste gas. However, due to the influence of comprehensive factors such as investment and operation costs and production status, the processes selected by each industry are not the same.

[0004] The adsorption method is an excellent process for the treatment of volatile organic compound (VOCs) waste gas. However, adsorbents all face the dilemma of adsorption saturation. The current mainstream process is to make the adsorbent have adsorption performance again through desorption and regeneration methods. General desorption and regeneration methods include steam desorption, hot air desorption, hot nitrogen desorption, etc., and the desorption temperature is generally 50 - 150°C.

[0005] For safety considerations, the current desorption methods used in the adsorption and desorption systems for high-concentration volatile organic compound (VOCs) waste gas are steam desorption, vacuum desorption, and nitrogen circulation desorption. However, steam desorption will bring secondary pollution and has unstable effects because it generates a large amount of wastewater and has a limited heating temperature. The requirements for vacuum desorption equipment are relatively high, so its large-scale application is restricted. Thermal nitrogen circulation desorption uses nitrogen for desorption, so the desorption temperature can be greatly increased, and thus the desorption effect will be significantly improved.

[0006] Although nitrogen circulation desorption has been proposed for many years and there are corresponding engineering cases, the current problem is that the effect of nitrogen circulation desorption is not ideal and it is difficult to meet the standards stably in engineering. The main problem is that the desorption temperature in the adsorption tower is only obtained by the heating link in the nitrogen circulation process, resulting in uneven and difficult-to-control desorption temperature in the adsorption tower. Summary of the Invention

[0007] Aiming at the problem that the temperature in the adsorption tower is neither balanced nor easy to control during the nitrogen circulation desorption process in the prior art, the purpose of the utility model is to provide an organic waste gas treatment device based on nitrogen circulation desorption to at least partially solve the above problems.

[0008] To achieve the above purpose, the technical solution of the utility model is as follows:

[0009] An organic waste gas treatment device based on nitrogen circulation desorption, comprising an adsorption and desorption tower, an adsorption system, a desorption system, and an outer cavity temperature control system;

[0010] The adsorption and desorption tower has a double-layer structure with an independent inner cavity and outer cavity, and an adsorbent is provided in the inner cavity;

[0011] The adsorption system includes an exhaust gas inlet pipe connected to the inner cavity and an adsorption fan connected to the inner cavity through an exhaust gas discharge pipe. Adsorption valves are installed on both the exhaust gas inlet pipe and the exhaust gas discharge pipe;

[0012] The desorption system includes a nitrogen inlet pipe and a nitrogen discharge pipe connected to the inner cavity. A nitrogen injection valve is installed on the nitrogen inlet pipe, and a nitrogen evacuation valve and a nitrogen cooling device are sequentially installed on the nitrogen discharge pipe along the gas flow direction; the desorption system further includes a desorption pipeline connected between the nitrogen inlet pipe and the nitrogen discharge pipe. The connection of the desorption pipeline to the nitrogen inlet pipe is located on the downstream side of the nitrogen injection valve, and the connection of the desorption pipeline to the nitrogen discharge pipe is located on the upstream side of the nitrogen evacuation valve; the desorption system further includes a condenser, a desorption fan, a desorption heating device, and a desorption main valve installed on the desorption pipeline in sequence starting from the adsorption and desorption tower and along the gas flow direction;

[0013] The outer cavity temperature control system includes an air inlet pipe and an air discharge pipe connected to the outer cavity. An air valve, a temperature control fan, and an outer cavity heating device are sequentially installed on the air inlet pipe along the gas flow direction, and a heat discharge valve is installed on the air discharge pipe; the outer cavity temperature control system further includes an intermediate pipeline connected between the air inlet pipe and the air discharge pipe. A temperature control switching valve is installed on the intermediate pipeline. The connection of the intermediate pipeline to the air inlet pipe is located between the air valve and the temperature control fan, and the connection of the intermediate pipeline to the air discharge pipe is located on the upstream side of the heat discharge valve.

[0014] In some preferred embodiments, both the nitrogen inlet pipe and the exhaust gas discharge pipe are connected to the upper part of the adsorption and desorption tower, and both the nitrogen discharge pipe and the exhaust gas inlet pipe are connected to the lower part of the adsorption and desorption tower.

[0015] In some preferred embodiments, the desorption system further includes a liquid storage tank, which is installed on the desorption pipeline and is located on the upstream side of the condenser.

[0016] In some preferred embodiments, there are two or more adsorption and desorption towers, which are arranged in parallel.

[0017] In some preferred embodiments, desorption valves are installed on both the nitrogen inlet pipe and the nitrogen exhaust pipe. The desorption valve on the nitrogen inlet pipe is located on the downstream side of the connection between the desorption pipeline and the nitrogen inlet pipe, and the desorption valve on the nitrogen exhaust pipe is located on the upstream side of the connection between the desorption pipeline and the nitrogen exhaust pipe.

[0018] In some preferred embodiments, a temperature control valve is installed on the air inlet pipe.

[0019] By adopting the above technical scheme, the beneficial effect of the utility model is that: the utility model configures the adsorption-desorption tower as a double-layer structure and sets an external cavity temperature control system, so that when nitrogen circulation desorption is carried out, the external cavity can be heated by the external cavity temperature control system, so that the adsorbent in the inner cavity can be maintained at the required temperature, not only can the adsorbent temperature at various parts of the inner cavity be balanced, but also the desorption temperature can be regulated by the external cavity temperature control system. Compared with the method of relying solely on a heat source to heat the circulating nitrogen to maintain the desorption temperature, the utility model can not only improve the desorption efficiency, but also facilitate the regulation of the desorption temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of Example 1 of the utility model.

[0021] Figure 2 This is a schematic diagram of the structure of Example 2 of the utility model.

[0022] In the figure: 1-adsorption and desorption tower, 2-waste gas inlet pipe, 3-waste gas exhaust pipe, 4-adsorption fan, 5-adsorption valve, 6-nitrogen inlet pipe, 7-nitrogen exhaust pipe, 8-desorption pipeline, 9-nitrogen injection valve, 10-nitrogen exhaust valve, 11-nitrogen cooling device, 12-condenser, 13-desorption fan, 14-desorption heating device, 15-desorption main valve, 16-liquid storage tank, 17-air inlet pipe, 18-air exhaust pipe, 19-intermediate pipeline, 20-air valve, 21-temperature control fan, 22-external cavity heating device, 23-heat exhaust valve, 24-temperature control switching valve, 25-desorption valve, 26-temperature control valve. DETAILED DESCRIPTION

[0023] The specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these implementation methods is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each implementation method of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] It should be noted that in the description of the present utility model, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc. is the description of the structure of the present utility model based on the figures shown, and is only for the convenience of describing the present utility model simply, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present utility model.

[0025] For the "first" and "second" in this technical solution, they are only the appellation distinctions for the same or similar structures, or the corresponding structures with similar functions, rather than the arrangement of the importance of these structures, nor do they have an order, or compare sizes, or other meanings.

[0026] In addition, unless otherwise clearly specified and defined, the terms "installation" and "connection" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two structures. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the general idea of the present utility model and in connection with the specific context of this solution.

[0027] Embodiment 1

[0028] An organic waste gas treatment device based on nitrogen cycle desorption, as Figure 1 shown, includes an adsorption and desorption tower 1, an adsorption system, a desorption system, and an external cavity temperature control system.

[0029] The adsorption and desorption tower 1 is generally in a cylindrical shape and is installed vertically. The adsorption and desorption tower 1 is a double-layer shell structure with an independent inner cavity and an outer cavity. Among them, an adsorbent is provided in the inner cavity. In addition, an exhaust port formed by a pipeline is provided at the upper end of the inner cavity, and an air inlet formed by a pipeline is provided at the lower end of the inner cavity. The exhaust port and the air inlet respectively penetrate the outer cavity (i.e., the surface of the adsorption and desorption tower 1) so that the inner cavity can communicate with the outside of the adsorption and desorption tower 1.

[0030] The adsorption system includes an exhaust gas inlet pipe 2, an exhaust gas discharge pipe 3, and an adsorption fan 4. One end of the exhaust gas inlet pipe 2 is connected to the inner cavity through the air inlet, and the other end of the exhaust gas inlet pipe 2 is used to receive exhaust gas. One end of the exhaust gas discharge pipe 3 is connected to the inner cavity through the exhaust port, and the other end of the exhaust gas discharge pipe 3 is connected to the suction end of the adsorption fan 4. Adsorption valves 5 are installed on both the exhaust gas inlet pipe 2 and the exhaust gas discharge pipe 3.

[0031] The desorption system includes a nitrogen inlet pipe 6, a nitrogen discharge pipe 7, and a desorption pipeline 8. One end of the nitrogen inlet pipe 6 is fixedly connected to the upper end of the adsorption and desorption tower 1 and is in communication with the inner cavity. The other end of the nitrogen inlet pipe 6 is used to receive nitrogen supply. One end of the nitrogen discharge pipe 7 is fixedly connected to the lower end of the adsorption and desorption tower 1 and is also in communication with the inner cavity. The other end of the nitrogen discharge pipe 7 is used to receive the discharged nitrogen. A nitrogen injection valve 9 is installed on the nitrogen inlet pipe 6, and a nitrogen evacuation valve 10 and a nitrogen cooling device 11 are successively installed on the nitrogen discharge pipe 7 along the gas flow direction.

[0032] Both ends of the desorption pipeline 8 are respectively connected to the nitrogen inlet pipe 6 and the nitrogen discharge pipe 7. The connection point of the desorption pipeline 8 and the nitrogen inlet pipe 6 is located on the downstream side of the nitrogen injection valve 9, and the connection point of the desorption pipeline 8 and the nitrogen discharge pipe 7 is located on the upstream side of the nitrogen evacuation valve 10.

[0033] In addition, starting from the adsorption and desorption tower 1, a condenser 12, a desorption fan 13, a desorption heating device 14, and a desorption main valve 15 are successively installed on the desorption pipeline 8 along the gas flow direction. The desorption system further includes a liquid storage tank 16, which is also installed on the desorption pipeline 8 and is located on the upstream side of the condenser 12. Valves are usually installed at the refrigerant inlet, refrigerant discharge port of the condenser 12, and the discharge port of the liquid storage tank 10. In addition, a temperature sensor is usually installed at the refrigerant discharge port of the condenser 12 to facilitate the detection of the discharge temperature of the refrigerant.

[0034] The outer cavity temperature control system includes an air inlet pipe 17, an air discharge pipe 18, and an intermediate pipeline 19. One end of the air inlet pipe 17 is fixedly connected to the adsorption and desorption tower 1 and is in communication with the outer cavity. The other end of the air inlet pipe 17 is used to receive air. One end of the air discharge pipe 18 is fixedly connected to the adsorption and desorption tower 1 and is in communication with the outer cavity. The other end of the air discharge pipe 18 is used to discharge air. An air valve 20, a temperature control fan 21, and an outer cavity heating device 22 are successively installed on the air inlet pipe 17 along the gas flow direction, and a heat discharge valve 23 is installed on the air discharge pipe 18.

[0035] Both ends of the intermediate pipeline 19 are respectively connected to the air inlet pipe 17 and the air discharge pipe 18. A temperature control switching valve 24 is installed on the intermediate pipeline 19. The connection point of the intermediate pipeline 19 and the air inlet pipe 17 is located between the air valve 20 and the temperature control fan 21, and the connection point of the intermediate pipeline 19 and the air discharge pipe 18 is located on the upstream side of the heat discharge valve 23.

[0036] The working process of the organic waste gas treatment equipment based on nitrogen cycle desorption provided by the embodiment of the present utility model is as follows:

[0037] 1. Adsorption: Open the adsorption valves 5 on the waste gas inlet pipe 2 and the waste gas discharge pipe 3, close all other valves and devices, and turn on the adsorption fan 4. The waste gas enters the inner cavity of the adsorption and desorption tower 1 along the waste gas inlet pipe 2, and the volatile organic compounds (VOCs) are adsorbed by the adsorbent. Then, the waste gas is discharged by the adsorption fan 4 along the waste gas discharge pipe 3 until the adsorbent reaches saturation and proceeds to the next step.

[0038] 2. Nitrogen replacement: Open the nitrogen injection valve 9 and the nitrogen evacuation valve 10, and close all other valves and devices. Nitrogen continuously enters the inner cavity of the adsorption and desorption valve 1, thereby discharging the residual waste gas in the inner cavity through nitrogen, and then proceeding to the next step.

[0039] 3. Desorption: Open the main desorption valve 15, the condenser 12, the desorption fan 13, and the desorption heating device 14, and close all other valves and devices. The nitrogen in the inner cavity of the adsorption and desorption tower 1 circulates under a heated environment. The hot nitrogen will release the volatile organic compounds (VOCs) adsorbed by the adsorbent. When the mixed gas passes through the condenser 12, it will be cooled, so that the volatile organic compounds (VOCs) in it will condense and liquefy, and be collected in the liquid storage tank 16 until no more liquid flows into the liquid storage tank 16.

[0040] Desorption is an endothermic process. Therefore, during the desorption process, open the temperature control switching valve 24 and the outer cavity heating device 22 to make the air in the outer cavity circulate and heat, so as to better ensure and maintain the thermal environment of the inner cavity.

[0041] 4. Purge: Open the nitrogen injection valve 9, the nitrogen evacuation valve 10, and the nitrogen cooling device, and close all other valves and devices. In this way, the residual volatile organic compounds (VOCs) in the inner cavity are carried away by nitrogen, and part of the heat in the inner cavity can also be carried away. After purging for a period of time, proceed to the next step.

[0042] 5. Cooling: Open the air valve 20, the temperature control fan 21, and the heat discharge valve 23, and close all other valves and devices. In this way, the heat in the inner cavity is continuously carried away by air until the adsorbent in the inner cavity cools down, and then the above steps can be repeated.

[0043] It is easy to understand that temperature sensors are connected to the inner cavity, the outer cavity, the desorption pipeline 8, and the air inlet pipe 17 to facilitate knowing the temperature.

[0044] Embodiment 2

[0045] On the basis of the above embodiment, in this embodiment, two adsorption and desorption towers 1 are configured and the two adsorption and desorption towers 1 are arranged in parallel.

[0046] Specifically, the exhaust gas inlet pipes 2 configured for the two adsorption and desorption towers 1 (referred to as Tower A and Tower B respectively) are connected to the same exhaust gas source, and the exhaust gas inlet pipes 3 configured for the two adsorption and desorption towers 1 are connected to the same adsorption fan 4.

[0047] The nitrogen inlet pipes 6 configured for the two adsorption and desorption towers 1 are connected to the same nitrogen injection valve 9, thus sharing the same nitrogen source. In addition, desorption valves 25 are additionally installed on the nitrogen inlet pipes 6 configured for the two adsorption and desorption towers 1. The desorption valves 25 are located on the downstream side of the nitrogen injection valve 9. The connection points of the desorption pipelines 8 with the two nitrogen inlet pipes 6 are both located between their respective desorption valves 25 and the nitrogen injection valve 9.

[0048] The nitrogen discharge pipes 7 configured for the two adsorption and desorption towers 1 are connected to the same nitrogen evacuation valve 10, and share the same nitrogen cooling device 11 on the downstream side. In addition, desorption valves 25 are additionally installed on the nitrogen discharge pipes 7 configured for the two adsorption and desorption towers 1. The desorption valves 25 are located on the upstream side of the nitrogen evacuation valve 10. The connection points of the desorption pipelines 8 with the two nitrogen discharge pipes 7 are both located between their respective desorption valves 25 and the nitrogen evacuation valve 10.

[0049] The two adsorption and desorption valves 1 share the same air inlet pipe 17. One end of the air inlet pipe 17 has two branch pipes, and the two branch pipes are respectively connected to the outer cavities of the two adsorption and desorption valves 1, and temperature control valves 26 are installed on both branch pipes.

[0050] The working process of the organic waste gas treatment equipment based on nitrogen cycle desorption provided by the embodiment of the present utility model is as follows:

[0051] 1. Adsorption by Tower A: Open the adsorption valves 5 on the exhaust gas inlet pipe 2 and the exhaust gas discharge pipe 3 belonging to Tower A, close all other valves and devices, and turn on the adsorption fan 4. The exhaust gas enters the inner cavity of Tower A along the exhaust gas inlet pipe 2, and the volatile organic compounds (VOCs) therein are adsorbed by the adsorbent. Then the exhaust gas is discharged by the adsorption fan 4 along the exhaust gas discharge pipe 3 until the adsorbent reaches saturation, and then Tower A enters the next step.

[0052] 2. Nitrogen replacement in Tower A: Open the nitrogen injection valve 9 and the nitrogen evacuation valve 10, and open the 2 desorption valves 25 belonging to Tower A, and close all other valves and devices. Nitrogen continuously enters the inner cavity of Tower A, so as to discharge the residual exhaust gas in the inner cavity of Tower A through nitrogen, and then Tower A enters the next step.

[0053] 3. Desorption of Tower A: Open the main desorption valve 15, the condenser 12, the desorption fan 13 and the desorption heating device 14. Open the two desorption valves 25 belonging to Tower A, and close all other valves and devices. This allows the nitrogen gas in the inner cavity of Tower A to circulate under a heated environment. The hot nitrogen gas will cause the volatile organic compounds (VOCs) adsorbed by the adsorbent to be released. When the mixed gas passes through the condenser 12, it will be cooled, causing the VOCs in it to condense and liquefy, and be collected in the liquid storage tank 16 until no more liquid flows into the liquid storage tank 16. Then Tower A proceeds to the next step.

[0054] Desorption is an endothermic process. Therefore, during desorption, open the temperature control switching valve 24 and the outer cavity heating device 22, and open the temperature control valve 26 connected to Tower A to make the air in the outer cavity of Tower A circulate and be heated, thus better ensuring and maintaining the thermal environment of the inner cavity of Tower A.

[0055] 4. Purge of Tower A: Open the nitrogen injection valve 9, the nitrogen evacuation valve 10 and the nitrogen cooling device. Open the two desorption valves 25 belonging to Tower A, and close all other valves and devices. In this way, the residual VOCs in the inner cavity of Tower A are carried away by nitrogen, and part of the heat in the inner cavity of Tower A is also removed. After purging for a period of time, Tower A proceeds to the next step.

[0056] 5. Cooling of Tower A: Open the air valve 20, the temperature control fan 21 and the heat discharge valve 23. Open the temperature control valve 26 connected to Tower A, and close all other valves and devices. In this way, the heat in the inner cavity of Tower A is continuously removed by air until the adsorbent in the inner cavity of Tower A is cooled, and then the above steps can be repeated.

[0057] It is easy to understand that Tower A and Tower B can take turns to perform the adsorption and desorption processes, which can improve the working efficiency of the equipment. Similarly, there can be more adsorption and desorption towers 1, thus further improving the working efficiency of the equipment.

[0058] The above describes the embodiments of the present invention in detail in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principles and spirit of the present invention, various changes, modifications, substitutions and variations made to these embodiments still fall within the protection scope of the present invention.

Claims

1. An organic waste gas treatment device based on nitrogen circulation desorption, characterized in that: It includes an adsorption and desorption tower, an adsorption system, a desorption system and an outer cavity temperature control system; The adsorption and desorption tower has a double-layer structure with an inner cavity and an outer cavity that are independent of each other, and an adsorbent is provided in the inner cavity; The adsorption system includes an exhaust gas inlet pipe connected to the inner cavity and an adsorption fan connected to the inner cavity through an exhaust gas discharge pipe. Adsorption valves are installed on both the exhaust gas inlet pipe and the exhaust gas discharge pipe; The desorption system includes a nitrogen inlet pipe and a nitrogen discharge pipe connected to the inner cavity. A nitrogen injection valve is installed on the nitrogen inlet pipe, and a nitrogen evacuation valve and a nitrogen cooling device are installed on the nitrogen discharge pipe in sequence along the gas flow direction; The desorption system also includes a desorption pipeline connected between the nitrogen inlet pipe and the nitrogen discharge pipe. The connection point of the desorption pipeline and the nitrogen inlet pipe is located on the downstream side of the nitrogen injection valve, and the connection point of the desorption pipeline and the nitrogen discharge pipe is located on the upstream side of the nitrogen evacuation valve; The desorption system also includes a condenser, a desorption fan, a desorption heating device and a desorption main valve that are installed on the desorption pipeline in sequence starting from the adsorption and desorption tower and along the gas flow direction; The outer cavity temperature control system includes an air inlet pipe and an air discharge pipe connected to the outer cavity. An air valve, a temperature control fan and an outer cavity heating device are installed on the air inlet pipe in sequence along the gas flow direction, and a heat discharge valve is installed on the air discharge pipe; The outer cavity temperature control system also includes an intermediate pipeline connected between the air inlet pipe and the air discharge pipe. A temperature control switching valve is installed on the intermediate pipeline. The connection point of the intermediate pipeline and the air inlet pipe is located between the air valve and the temperature control fan, and the connection point of the intermediate pipeline and the air discharge pipe is located on the upstream side of the heat discharge valve.

2. The organic waste gas treatment equipment based on nitrogen circulation desorption according to claim 1, wherein: Both the nitrogen inlet pipe and the exhaust gas discharge pipe are connected to the upper part of the adsorption and desorption tower, and both the nitrogen discharge pipe and the exhaust gas inlet pipe are connected to the lower part of the adsorption and desorption tower.

3. The organic waste gas treatment equipment based on nitrogen circulation desorption according to claim 1, wherein: The desorption system also includes a liquid storage tank, which is installed on the desorption pipeline and is located on the upstream side of the condenser.

4. The organic waste gas treatment equipment based on nitrogen circulation desorption according to claim 1, characterized in that: There are two or more adsorption and desorption towers, which are arranged in parallel.

5. The organic waste gas treatment equipment based on nitrogen cycle desorption according to claim 4, characterized in that: Desorption valves are installed on both the nitrogen inlet pipe and the nitrogen discharge pipe. The desorption valve on the nitrogen inlet pipe is located on the downstream side of the connection point of the desorption pipeline and the nitrogen inlet pipe, and the desorption valve on the nitrogen discharge pipe is located on the upstream side of the connection point of the desorption pipeline and the nitrogen discharge pipe.

6. The organic waste gas treatment equipment based on nitrogen circulation desorption according to claim 4, characterized in that: A temperature control valve is installed on the air inlet pipe.

Images