Refrigerant refrigeration VOC (volatile organic compound) purification, recovery and cyclic utilization device

Abstract

The utility model belongs to the technical field of petrifaction and coal chemical industry, and particularly relates to a refrigerant refrigeration VOC (volatile organic compound) purifying, recycling and recycling device which comprises a drying and cooling unit and a separating unit, and the drying and cooling unit comprises a mixed refrigerant compressor, a VOC compressor, a dryer, a main heat exchanger, a normal-temperature purified nitrogen pipe network and a normal-temperature recycled oil pipeline. According to the VOC characteristics of atmospheric storage tanks of petroleum and petrochemical industry and coal chemical industry, low-temperature condensation purification VOC treatment is carried out by using a cryogenic technology, the atmospheric storage tanks comprise an oil product storage tank or a methanol storage tank and the like, so that purification recovery and cyclic utilization of VOC are realized, and zero emission of VOC is realized. Components of the mixed refrigerant can be adjusted according to actual conditions, so that the device adapts to changes of production conditions and flexibly deals with different VOC treatment, and good purification and recovery effects can be achieved.

Description

Technical Field

[0001] This utility model relates to the field of petrochemical equipment technology, and in particular to a refrigerant refrigeration VOC purification, recovery and recycling device. Background Technology

[0002] VOC stands for volatile organic compounds, sometimes abbreviated as VOCs. It is also known as volatile organic compounds, volatile organic compounds, volatile pollutants, volatile organic pollutants, or volatile organic waste gas.

[0003] The atmospheric pressure raw material tank area, atmospheric pressure intermediate product tank area, and atmospheric pressure product tank area in the petroleum and petrochemical industry will generate volatile organic compound (VOC) waste gas. This waste gas is mostly nitrogen and contains a small amount of volatile organic compounds. This waste gas is a serious pollutant to the atmospheric environment. Therefore, it cannot be directly discharged into the atmosphere. It can only be discharged into the atmosphere after strict purification treatment to meet the emission standards stipulated by the state.

[0004] Currently, the main VOC purification technologies in China include activated adsorption, combustion, and absorption degassing. These methods all have certain drawbacks. In most cases, absorption and adsorption involve the transfer of harmful substances, requiring secondary or multiple treatments to achieve harmlessness. The purified gas is released into the atmosphere without being recycled. Although VOC combustion can meet emission standards, high-temperature combustion or catalytic oxidation will release carbon dioxide and nitrogen oxides into the atmosphere and consume fuel. The purified gas is also not recycled. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing VOC treatment equipment, such as high energy consumption, high risk, and large amounts of waste gas emissions into the environment, by proposing a refrigerant-cooled VOC purification, recovery, and recycling device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A refrigerant-cooled VOC purification, recovery, and recycling device includes a drying and cooling unit and a separation unit.

[0008] The drying and cooling unit includes a mixed refrigerant compressor, a VOC compressor, a dryer, a main heat exchanger, a normal temperature purified nitrogen pipeline network, and a normal temperature oil recovery pipeline.

[0009] The main heat exchanger is connected to the mixed refrigerant compressor via a pipeline, and the mixed refrigerant compressor is connected back to the main heat exchanger via a pipeline.

[0010] An atmospheric pressure storage tank is connected via a pipeline to the VOC compressor for compressing and pressurizing VOCs, the VOC compressor is connected via a pipeline to the dryer for dehydrating and drying VOCs, and the dryer is connected via a pipeline to the main heat exchanger.

[0011] The bottom outlet of the main heat exchanger is connected to the bottom of the atmospheric pressure storage tank through the ambient temperature recovery oil pipeline;

[0012] The nitrogen output pipeline of the main heat exchanger is connected to the atmospheric pressure storage tank through the ambient temperature purified nitrogen pipeline network.

[0013] The separation unit includes a separation tank and a low-temperature oil recovery pipeline;

[0014] The middle part of the main heat exchanger is connected to the separation tank via a pipeline. The liquid outlet at the bottom of the separation tank is connected to the bottom of the main heat exchanger via the low-temperature recovery oil pipeline. The gas outlet at the top of the separation tank is connected to the upper part of the main heat exchanger via a pipeline.

[0015] Preferably, the main heat exchanger is a multi-channel plate-fin aluminum heat exchanger.

[0016] Preferably, the separation tank is a cryogenic separation tank.

[0017] Preferably, it also includes a throttling device, the main heat exchanger is connected to the throttling device via a pipe, and the throttling device is connected back to the main heat exchanger via a pipe.

[0018] Preferably, the main heat exchanger is a multi-channel low-temperature heat exchanger.

[0019] Beneficial effects:

[0020] A refrigerant-cooled VOC purification, recovery, and recycling device utilizes cryogenic technology for low-temperature condensation purification of VOCs from atmospheric pressure storage tanks in petroleum, petrochemical, and coal chemical industries. The atmospheric pressure storage tanks include oil tanks or methanol tanks, etc. VOCs are deeply cooled in a multi-channel cryogenic heat exchanger, where the contained organic matter condenses into a liquid phase. This liquid phase is then separated in a cryogenic buffer separator into cryogenically recovered oil (or organic matter such as alcohols, aldehydes, ketones, and ethers) and cryogenically purified nitrogen. The nitrogen purity can reach 99.999%. The cryogenically recovered oil (or organic matter such as alcohols, aldehydes, ketones, and ethers) is reheated to room temperature by the multi-channel heat exchanger and can be returned to the original atmospheric pressure storage tank for reuse. Similarly, the cryogenically purified nitrogen is reheated by the multi-channel heat exchanger and sent to the purified nitrogen pipeline network for reuse, thereby achieving VOC purification, recovery, and recycling, and realizing zero VOC emissions.

[0021] The composition of the mixed refrigerant can be adjusted according to the actual situation, so that the equipment can adapt to changes in production conditions and flexibly deal with different VOC treatments, and can achieve good purification and recovery effects. Attached Figure Description

[0022] Figure 1 This is a system diagram of a refrigerant refrigeration VOC purification, recovery and recycling device according to Embodiment 1 of this utility model.

[0023] In the diagram: 100, Drying and cooling unit; 200, Separation unit; 300, Throttling device; 400, Mixed refrigerant compressor; 11, Atmospheric pressure storage tank; 12, VOC compressor; 13, Dryer; 14, Main heat exchanger; 15, Atmospheric temperature purified nitrogen pipeline; 16, Atmospheric temperature oil recovery pipeline; 21, Separation tank; 23, Low temperature oil recovery pipeline. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0025] Example 1

[0026] This utility model belongs to the field of petrochemical and coal chemical technology. The atmospheric pressure storage tank 11 is an external device. The purpose of this utility model is to purify and recover VOCs in the atmospheric pressure storage tank 11. The atmospheric pressure storage tank 11 includes an oil storage tank and a methanol storage tank.

[0027] Reference Figure 1 A refrigerant-cooled VOC purification, recovery, and recycling device includes a drying and cooling unit 100 and a separation unit 200.

[0028] The drying and cooling unit 100 includes a mixed refrigerant compressor 400, a VOC compressor 12, a dryer 13, a main heat exchanger 14, a normal temperature purified nitrogen pipeline network 15, and a normal temperature oil recovery pipeline 16.

[0029] The main heat exchanger 14 is connected to the mixed refrigerant compressor 400 via a pipeline, and the mixed refrigerant compressor 400 is connected back to the main heat exchanger 14 via a pipeline;

[0030] The atmospheric pressure storage tank 11 is connected via a pipeline to the VOC compressor 12 for compressing and pressurizing VOCs, the VOC compressor 12 is connected via a pipeline to the dryer 13 for dehydrating and drying VOCs, and the dryer 13 is connected via a pipeline to the main heat exchanger 14.

[0031] The bottom outlet of the main heat exchanger 14 is connected to the bottom of the atmospheric pressure storage tank 11 through the ambient temperature recovery oil pipeline 16;

[0032] The nitrogen output pipeline of the main heat exchanger 14 is connected to the atmospheric pressure storage tank 11 through the ambient temperature purified nitrogen pipeline network 15;

[0033] The separation unit 200 includes a separation tank 21 and a low-temperature oil recovery pipeline 23;

[0034] The middle part of the main heat exchanger 14 is connected to the separator 21 through a pipe. The liquid outlet at the bottom of the separator 21 is connected to the bottom of the main heat exchanger 14 through the low-temperature recovery oil pipeline 23. The gas outlet at the top of the separator 21 is connected to the upper part of the main heat exchanger 14 through a pipe.

[0035] Preferably, the main heat exchanger 14 is a multi-channel plate-fin aluminum heat exchanger.

[0036] Preferably, the separation tank 21 is a cryogenic separation tank.

[0037] A refrigerant-based VOC purification, recovery, and recycling device, comprising the following steps:

[0038] (1) VOC from the atmospheric pressure storage tank 11 is collected through pipeline and sent to the suction port of the VOC compressor 12, and the VOC pressure rises to 0.2MPa to 1MPa;

[0039] (2) After being dehydrated by the dryer 13, the pressurized VOC enters the main heat exchanger 14, where it exchanges heat with the cold medium and cools down to below minus 160 degrees Celsius.

[0040] (3) The high-pressure VOC after cooling enters the separator 21 and is separated into low-temperature liquid oil and low-temperature gaseous nitrogen;

[0041] (4) The low-temperature liquid phase oil at the bottom of the separator 21 is returned to the main heat exchanger 14 to be reheated to room temperature, and then sent back to the atmospheric pressure storage tank 11 or into the downstream device.

[0042] (5) The gaseous low-temperature nitrogen at the top of the separator 21 is also returned to the main heat exchanger 14 to be reheated to room temperature, and the purified nitrogen is maintained at a pressure of more than 20 kPa and enters the room temperature purified nitrogen pipeline 15 as the sealed nitrogen of the atmospheric pressure storage tank 11 for recycling.

[0043] Preferably, the low-temperature liquid phase oil mentioned in steps 3 and 4 can also be an organic compound such as alcohols, aldehydes, ketones, or ethers.

[0044] The VOCs that have been pressurized and dried are cooled by a low-temperature cold medium in the main heat exchanger 14 and separated into low-temperature oil and purified nitrogen in the separator 21. The low-temperature oil is returned to the atmospheric pressure storage tank 11 or sent directly to the downstream device after being reheated to room temperature in the main heat exchanger 14. The low-temperature purified nitrogen is entered into the ambient temperature purified nitrogen pipeline 15 after being reheated and used as the sealed nitrogen for circulation in the atmospheric pressure storage tank 11. The entire zero-emission VOC purification, recovery and recycling device does not discharge any materials into the environment. The low-temperature oil can also be organic compounds such as alcohols, aldehydes, ketones and ethers.

[0045] Preferably, the VOC compressed by the VOC compressor 12 needs to be dried, and three dryers 13 are used for isobaric drying. The condensate from the regenerated gas is returned to the water-containing atmospheric pressure storage tank 11.

[0046] Preferably, the dryer 13 is regenerated at low pressure using the main heat exchanger 14, and the condensate from the regenerated gas is sent back to the water-containing atmospheric pressure storage tank 11.

[0047] Preferably, the main heat exchanger 14 is a multi-channel low-temperature heat exchanger, and the low-temperature cooling capacity of the main heat exchanger 14 is provided by a mixed refrigerant.

[0048] Preferably, under low-temperature conditions, the oil contained in the high-pressure VOC is condensed into a liquid phase and separated into low-temperature oil and purified nitrogen gas in the separator 21. The residual oil content in the purified nitrogen is controlled by temperature; the lower the temperature, the lower the oil content. The oil can also be organic compounds such as alcohols, aldehydes, ketones, and ethers.

[0049] Reheating the recovered oil to room temperature can both recycle its low-temperature cold energy and reduce the material requirements of its transportation pipelines.

[0050] The separator 21 has a relatively high pressure, and can use its own pressure to send the recovered oil back to the original storage tank, or use its own pressure to send the recovered oil to downstream equipment.

[0051] The recovered purified nitrogen is warmed to room temperature to utilize its low-temperature cooling capacity to cool the high-pressure VOCs, while also reducing the material requirements for the delivery pipelines and purified nitrogen pipeline network.

[0052] It also includes a throttle valve 300, the main heat exchanger 14 is connected to the throttle valve 300 via a pipe, and the throttle valve 300 is connected back to the main heat exchanger 14 via a pipe;

[0053] It also includes a mixed refrigerant compressor 400, the main heat exchanger 14 is connected to the mixed refrigerant compressor 400 via a pipeline, and the mixed refrigerant compressor 400 is connected back to the main heat exchanger 14 via a pipeline.

[0054] The composition of the mixed refrigerant in the mixed refrigerant compressor 400 is existing technology and can be adjusted according to actual conditions to adapt the device to changes in production conditions. One of the usable mixed refrigerants is R407C, a mixture of tetrafluoroethane, pentafluoroethane and difluoromethane. This utility model can use this mixed refrigerant, or other mixed refrigerants can be used according to actual conditions. The composition of the mixed refrigerant does not limit this utility model in any way.

[0055] Since the mixed refrigerant is a mixture, its endothermic boiling process is a temperature-changing process, which makes the heat transfer temperature difference between the hot flow and the cold flow in the heat exchanger always low, thus improving the efficiency of the main heat exchanger 14.

[0056] The throttle 300 is used for throttling refrigeration.

[0057] The advantage of using the mixed refrigerant compressor 400 is that the composition of the mixed refrigerant can be adjusted according to the actual situation, so that the device can adapt to changes in production conditions, flexibly deal with different VOC treatments, and achieve good purification and recovery effects.

[0058] It should be noted that the specific models of the individual devices used in this utility model shall be selected by those skilled in the art, and all of the above individual devices belong to the prior art, which will not be elaborated in this solution.

[0059] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A refrigerant-based VOC purification, recovery, and recycling device, characterized in that, Includes a drying and cooling unit (100) and a separation unit (200), The drying and cooling unit (100) includes a mixed refrigerant compressor (400), a VOC compressor (12), a dryer (13), a main heat exchanger (14), a normal temperature purified nitrogen pipeline (15), and a normal temperature oil recovery pipeline (16); The main heat exchanger (14) is connected to the mixed refrigerant compressor (400) via a pipe, and the mixed refrigerant compressor (400) is connected back to the main heat exchanger (14) via a pipe; An atmospheric pressure storage tank (11) is connected via a pipe to the VOC compressor (12) for compressing and pressurizing VOCs, the VOC compressor (12) is connected via a pipe to the dryer (13) for dehydrating and drying VOCs, and the dryer (13) is connected via a pipe to the main heat exchanger (14). The bottom outlet of the main heat exchanger (14) is connected to the bottom of the atmospheric pressure storage tank (11) through the ambient temperature recovery oil pipeline (16); The nitrogen output pipeline of the main heat exchanger (14) is connected to the atmospheric pressure storage tank (11) through the ambient temperature purified nitrogen pipeline network (15); The separation unit (200) includes a separation tank (21) and a low-temperature oil recovery pipeline (23); The middle part of the main heat exchanger (14) is connected to the separation tank (21) through a pipe. The liquid outlet at the bottom of the separation tank (21) is connected to the bottom of the main heat exchanger (14) through the low temperature recovery oil pipeline (23). The gas outlet at the top of the separation tank (21) is connected to the upper part of the main heat exchanger (14) through a pipe.

2. The refrigerant refrigeration VOC purification, recovery and recycling device according to claim 1, characterized in that, The main heat exchanger (14) is a multi-channel plate-fin aluminum heat exchanger.

3. The refrigerant refrigeration VOC purification, recovery and recycling device according to claim 2, characterized in that, The separation tank (21) is a cryogenic separation tank.

4. The refrigerant refrigeration VOC purification, recovery and recycling device according to claim 3, characterized in that, It also includes a throttle (300), the main heat exchanger (14) is connected to the throttle (300) via a pipe, and the throttle (300) is connected back to the main heat exchanger (14) via a pipe.

5. The refrigerant refrigeration VOC purification, recovery and recycling device according to claim 1, characterized in that, The main heat exchanger (14) is a multi-channel low-temperature heat exchanger.

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