A bimodal polyethylene purge gas separation device

Abstract

The utility model relates to bimodal polyethylene purification gas separation technical field especially relates to a bimodal polyethylene purification gas separation device. The bimodal polyethylene purification gas separation device includes: the purification tank and a plurality of pipelines, the blanking tube, the torch connecting pipe, the sealing assembly, and the purification tank is fixedly connected with the bag filter tank through the pipeline, the bag filter tank is fixedly connected with the tee pipe through the pipeline, the bottom of tee pipe is fixedly connected with the filter through the pipeline, the filter is fixedly connected with the cooler through the pipeline, the cooler is fixedly connected with the cryogenic refrigerator through the pipeline, and the cryogenic refrigerator is fixedly connected with the separation tank through the pipeline. The utility model can efficiently separate nitrogen, light hydrocarbon and heavy components in the discharge gas of purification tank V406, realizes separation and recycling of nitrogen, recycling of light hydrocarbon, reduction of raw material loss such as ethylene, butene-1, reduction of production cost, and through membrane separation and compression cooling synergistic technology, separation efficiency is improved, waste gas burning quantity is reduced, and green environmental protection production demand is met.

Description

Technical Field

[0001] This utility model relates to the field of bimodal polyethylene purified gas separation technology, and in particular to a bimodal polyethylene purified gas separation device. Background Technology

[0002] The bimodal polyethylene purification gas separation unit is a device used to separate and treat the purified gas generated during the bimodal polyethylene production process. Its main function is to separate and purify various components in the purified gas through a series of separation technologies, such as distillation and adsorption, and recover valuable gases, such as ethylene and hydrogen, so that they can be recycled back into the production system for reuse. At the same time, impurity gases are discharged to achieve the goals of energy saving and emission reduction, reducing production costs and environmental pollution, and ensuring the efficient, stable and environmentally friendly operation of the bimodal polyethylene production process.

[0003] The original technology involved obtaining bimodal polyethylene through a gas-phase reactor, which, after gas-solid separation, entered a purification tank. In the purification tank, a conical component (commonly known as a "general's cap") was installed at the top of the conical section. Hot nitrogen at a rate of 400-800 kg / h, mixed with a small amount of steam (80-95°C), was introduced to deactivate residual triethylaluminum and catalyst in the polyethylene powder entering the purification tank. Below this, another conical component was installed, through which hot nitrogen at 200-400°C (80-95°C) was introduced to remove moisture from the polyethylene powder and hydrocarbons (including ethylene, propane, butene, etc.) carried by the volatile powder, achieving a drying effect. The mixed gas in the purification tank was then filtered through a bag filter to remove fine powder before being discharged to the flare via a pressure controller.

[0004] The original design had the following problems:

[0005] 1. Resource waste: Light hydrocarbons such as ethylene and butene-1, as well as nitrogen, are not recovered, resulting in low raw material utilization.

[0006] 2. Environmental pressure: Direct combustion of waste gas produces CO2 and pollutants, which does not meet the requirements of green and environmentally friendly production;

[0007] 3. High energy consumption: Existing technologies rely on a large amount of fresh nitrogen for replenishment, which increases production costs; therefore, it is necessary to provide a new bimodal polyethylene purification gas separation device to solve the above-mentioned technical problems. Utility Model Content

[0008] To solve the above-mentioned technical problems, this utility model provides a bimodal polyethylene purified gas separation device.

[0009] This utility model provides a bimodal polyethylene purification gas separation device, comprising: a purification tank and multiple pipes, a discharge pipe, a flare connection pipe, and a sealing assembly. The purification tank is fixedly connected to a bag filter tank via pipes. The bag filter tank is fixedly connected to a tee pipe via pipes. The bottom end of the tee pipe is fixedly connected to a filter via pipes. The filter is fixedly connected to a cooler via pipes. The cooler is fixedly connected to a cryogenic cooler via pipes. The cryogenic cooler is fixedly connected to a separation tank via pipes. The separation tank is fixedly connected to a compressor via pipes. The compressor is fixedly connected to a membrane separator via pipes. The bottom end of the purification tank is fixedly connected to a discharge pipe via pipes. A discharge control valve is installed on the pipe between the purification tank and the discharge pipe via the sealing assembly. One end of the tee pipe is fixedly connected to a flare connection pipe. A first pressure control valve is provided between the tee pipe and the flare connection pipe.

[0010] Preferably, the sealing assembly includes a sliding groove, with two sliding grooves respectively opened inside both ends of the discharge control valve. Multiple telescopic rods are fixedly connected to one side of the inner side of the sliding groove, and springs are sleeved on the outside of the telescopic rods. Two limiting rings are fixedly connected to the far side of the multiple telescopic rods, and an annular block is fixedly connected to the far side of each of the two limiting rings. Connecting rings are threaded to both sides of the outer side of the discharge control valve. Sealing gaskets are fixedly connected to the far side of each of the two annular blocks. Sealing grooves are opened on the near side of the two pipes at the bottom of the purification tank.

[0011] Preferably, flow control valves are installed on both pipes on one side of the purification tank.

[0012] Preferably, a shut-off valve is installed on the pipe between the tee and the filter.

[0013] Preferably, a second pressure control valve is installed on each of the two pipes at the top right side of the membrane separator. The two pipes at the top right side of the membrane separator are used to connect an additional purification tank and a circulating gas compressor, respectively.

[0014] Preferably, a liquid level control valve is installed on the bottom right pipe of the membrane separator, and the bottom right pipe of the membrane separator is used to connect to the heavy component processing tank.

[0015] Preferably, the cooler is made of propane.

[0016] Compared with related technologies, the bimodal polyethylene purified gas separation device provided by this utility model has the following beneficial effects:

[0017] This utility model can efficiently separate nitrogen, light hydrocarbons and heavy components from the exhaust gas of the purification tank V406, realize the separation and recycling of nitrogen, recover and utilize light hydrocarbons, reduce the loss of raw materials such as ethylene and butene-1, reduce production costs, and improve separation efficiency through membrane separation and compression cooling synergistic technology, reduce the amount of waste gas incinerated, and meet the needs of green and environmentally friendly production.

[0018] This invention involves tightening the connecting rings on both sides during the installation of the discharge control valve, causing the connecting rings to converge towards the discharge control valve. Then, the two pipes are brought into contact with the discharge control valve to complete the connection. During this process, the sealing groove contacts the sealing gasket, and pressure is applied to the annular block. This causes the limiting ring to slide inside the sliding groove, compressing the spring. The telescopic rod also retracts, preventing the spring from wobbling or deforming. This generates a rebound force, ensuring a tight contact between the sealing gasket and the sealing groove. This effectively prevents gas or liquid leakage from the connection point, thereby improving the sealing performance and reliability of the entire device during raw material transportation. Attached Figure Description

[0019] Figure 1 A schematic diagram of the structure of a bimodal polyethylene purified gas separation device provided by this utility model;

[0020] Figure 2 for Figure 1 The diagram shows the structure of the sealing assembly.

[0021] Numbered in the diagram: 1. Purification tank; 2. Bag filter tank; 3. Filter; 4. Cooler; 5. Deep cooler; 6. Separator; 7. Compressor; 8. Membrane separator; 9. Pipeline; 10. T-connector; 11. Feed pipe; 12. Flare connection pipe; 101. Flow control valve; 102. Feed control valve; 103. First pressure control valve; 104. Shut-off valve; 105. Second pressure control valve; 106. Liquid level control valve; 13. Sliding groove; 14. Telescopic rod; 15. Spring; 16. Limiting ring; 17. Annular block; 18. Connecting ring; 19. Sealing gasket; 20. Sealing groove. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0023] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0024] Please see Figures 1 to 2A bimodal polyethylene purified gas separation device is provided, comprising: a purification tank (1) and multiple pipes (9). The purification tank (1) plays a key role in the initial purification of the entire separation device, laying the foundation for subsequent separation steps. Flow control valves (101) are installed on both pipes (9) on one side of the purification tank (101), which can precisely regulate the gas flow rate to ensure that the purified gas flows in the pipe at a suitable flow rate, avoiding excessive or insufficient flow that may affect the subsequent treatment effect. A bag filter tank (2) is fixedly connected to the purification tank (1) through the pipes (9). The bag filter tank (2) can further filter impurity particles in the purified gas, improve the cleanliness of the purified gas, and make the gas entering the subsequent stages purer. A three-way pipe (10) is fixedly connected to the bag filter tank (2) through the pipes (9). The three-way pipe (10) can divert the gas to different directions to achieve switching between different treatment paths. A shut-off valve (104) is installed on the pipe (9) between the three-way pipe (10) and the filter (3). The shut-off valve (104) can quickly cut off the gas flow to the filter (3) when needed, which is convenient for equipment maintenance, repair or response to emergencies.

[0025] The bottom end of the three-way pipe (10) is fixedly connected to a filter (3) via a pipe (9). As mentioned above, the filter (3) can remove fine powder entrained in the gas, effectively preventing fine powder from entering subsequent equipment, reducing equipment wear, and extending equipment service life. The filter (3) is fixedly connected to a cooler (4) via a pipe (9). The cooler (4) can cool the purified gas, creating suitable conditions for subsequent cryogenic operations. By precisely controlling the temperature, the separation effect of the purified gas is improved. The cooler (4) is fixedly connected to a cryogenic cooler (5) via a pipe (9). The cryogenic cooler (5) further reduces the temperature of the purified gas, causing different components in the gas to undergo phase changes according to their respective physical properties, so as to better separate them. The cryogenic cooler (5) is fixedly connected to a separation tank (6) via a pipe (9). The separation tank (6) can effectively separate the liquid water produced after cryogenic treatment from the heavy components, realizing the separation of substances in different phases and improving the purity of the purified gas. The separator (6) is fixedly connected to a compressor (7) via a pipe (9). The compressor (7) pressurizes the gas to 1.5-2.0 MPa, providing suitable pressure conditions for the subsequent membrane separation system, enhancing the mobility of gas molecules, and facilitating the membrane separation process. The compressor (7) is fixedly connected to a membrane separator (8) via a pipe (9). The membrane separator (8) is the core equipment for separating nitrogen from light hydrocarbons.

[0026] Two second pressure control valves (105) are installed on the two pipes (9) at the top right side of the membrane separator (8). The second pressure control valves (105) can precisely adjust the gas pressure entering the additional purification tank and the circulating gas compressor to ensure stable gas delivery in subsequent processing stages and ensure safe operation of the equipment. The two pipes (9) at the top right side of the membrane separator (8) are used to connect the additional purification tank and the circulating gas compressor, respectively, expanding the processing path of the purified gas and realizing gas diversion for different purposes. A liquid level control valve (106) is installed on the pipe (9) at the bottom right side of the membrane separator (8). The liquid level control valve (106) can effectively control the liquid level in the pipe connected to the heavy component processing tank to ensure that the heavy components can be smoothly delivered to the heavy component processing tank for processing. The pipe (9) at the bottom right side of the membrane separator (8) is used to connect to the heavy component processing tank, which facilitates centralized processing of the separated heavy components and realizes the rational utilization of resources and environmental protection requirements.

[0027] The bottom end of the purification tank (1) is fixedly connected to the discharge pipe (11) via the pipe (9). The discharge pipe (11) is used to discharge the residual substances after treatment in the purification tank (1), ensuring the stability of the internal environment of the purification tank (1) and maintaining the purification efficiency. The pipe (9) between the purification tank (1) and the discharge pipe (11) is connected to the discharge control valve (102) via a sealing assembly. The sealing assembly includes a sliding groove (13). The two sliding grooves (13) are respectively opened inside the two ends of the discharge control valve (102). The sliding groove (13) provides a track for the sliding of the limit ring (16), ensuring the stability of the entire sealing assembly during operation. Multiple telescopic rods (14) are fixedly connected to one side of the inner side of the sliding groove (13). The telescopic rods (14) can help the spring (15) to remain stable when it is compressed, preventing the spring (15) from shaking and deforming, and ensuring the reliability of the sealing effect. A spring (15) is sleeved on the outside of the telescopic rod (14). The rebound force generated by the spring (15) after being compressed is the key force to make the sealing gasket (19) and the sealing groove (20) make tight contact, thereby effectively improving the sealing performance at the connection between the material control valve (102) and the pipeline (9) and preventing material leakage. Two limiting rings (16) are fixedly connected to the opposite sides of the multiple telescopic rods (14);

[0028] The limiting ring (16) slides within the sliding groove (13), and adjusts the sealing assembly by squeezing and resetting the spring (15), ensuring the continuity and stability of the seal. An annular block (17) is fixedly connected to the opposite sides of both limiting rings (16). The annular block (17) effectively transmits pressure, evenly applying the force of the spring (15) to the sealing gasket (19), enhancing the sealing effect. Connecting rings (18) are threaded onto both sides of the discharge control valve (102). The connecting rings (18) facilitate the installation and removal of the discharge control valve (102) by operators. During tightening, they also promote the sealing assembly's function, improving the sealing performance of the connection. A sealing gasket (19) is fixedly connected to the opposite sides of both annular blocks (17). The sealing gasket (19) directly contacts the sealing groove (20) on the pipe (9), forming a tight sealing structure that effectively prevents material leakage from the connection. A sealing groove (20) is provided on the adjacent side of the two pipes (9) at the bottom of the purification tank (1). The sealing groove (20) and the sealing gasket (19) cooperate with each other to further enhance the sealing performance of the connection and ensure that the connection between the purification tank (1) and the discharge pipe (11) is tight and reliable.

[0029] A flare connection pipe (12) is fixedly connected to one end of a tee pipe (10). The flare connection pipe (12) provides a discharge channel for gases that cannot be effectively recycled or require emergency discharge, ensuring the safe operation of the entire device. A first pressure control valve (103) is installed between the tee pipe (10) and the flare connection pipe (12). The first pressure control valve (103) can accurately control the gas pressure discharged to the flare connection pipe (12), avoiding safety accidents caused by excessive pressure. At the same time, it can also reasonably adjust the amount of gas discharged according to the actual production situation, reducing unnecessary energy waste and environmental pollution.

[0030] The working principle of the bimodal polyethylene purified gas separation device provided by this utility model is as follows:

[0031] The exhaust gas from V406, with a flow rate of 750 to 1300 kg / h, contains 3-5% ethylene, 75-90% nitrogen, and 10-15% propane, and first enters the purification tank (1). The purification tank (1) preliminarily purifies the exhaust gas, laying the foundation for subsequent steps. The exhaust gas drives the valve core of the flow control valve (101) to actuate. The flow control valve (101) precisely regulates the gas flow rate to ensure that the exhaust gas enters the subsequent pipeline (9) at a suitable flow rate, avoiding abnormal flow that could affect the subsequent treatment effect.

[0032] The flow-controlled exhaust gas is propelled along the pipe (9) into the bag filter tank (2). The flow of the exhaust gas drives the filter components inside the bag filter tank (2) to work, further filtering impurity particles in the exhaust gas, improving the cleanliness of the gas, and making the gas entering subsequent stages even purer.

[0033] The purified gas is pushed into the three-way pipe (10). When further filtration of fine powder is required, the gas pushes the valve disc of the shut-off valve (104) to open, and the gas flows to the filter (3). The flow of gas drives the filter medium in the filter (3) to work, removing the fine powder entrained in the gas, effectively preventing the fine powder from entering subsequent equipment, reducing equipment wear, and extending the service life of the equipment.

[0034] The gas treated by the filter (3) is pushed into the cooler (4). The cooler (4) uses an internal cooling medium, such as propane as a diluent, to cool the gas, reducing its temperature and creating suitable conditions for subsequent cryogenic operations. By precisely controlling the temperature, the separation effect of the purified gas is improved. The cooled gas is then pushed into the cryogenic chamber (5). The cryogenic chamber (5) further reduces the temperature of the purified gas, causing different components in the gas, such as water vapor and heavy components, to undergo phase changes according to their respective physical properties. Some of the gas is converted into a liquid state, which facilitates better separation.

[0035] The gas-liquid mixture after phase change propels it into the separator (6). Inside the separator (6), due to gravity and the density difference between different phases, liquid water and heavy components sink to the bottom of the separator (6), achieving separation of different phases and improving the purity of the purified gas. The separated gas propels it into the compressor (7), and the gas at the top of the separator (6) drives the piston of the compressor (7) to move, and the compressor (7) pressurizes the gas to 1.5-2.0 MPa. The pressurized gas propels it into the membrane separator (8). The flow of high-pressure gas causes the membrane module inside the membrane separator (8) to work. Based on the difference in gas permeation rate, nitrogen and light hydrocarbons are separated. The nitrogen and light hydrocarbon enriched gas separated by the membrane separator (8) partially drives the valve core of the second pressure control valve (105). After the second pressure control valve (105) precisely adjusts the pressure, it pushes the gas along the two pipes (9) at the top right to flow to the additional purification tank and the circulating gas compressor, respectively, to achieve gas diversion for different purposes. Nitrogen can be recycled to the vaporization and drying system of purification tank V406. After the light hydrocarbons pass the moisture test, they are sent to the circulating gas compressor for recovery. The heavy components separated by the membrane separator (8) drive the float of the level control valve (106) to move. The level control valve (106) controls the valve opening according to the liquid level to ensure that the heavy components can flow smoothly along the bottom pipe (9) on the right side to the heavy component processing tank, realizing the rational use of resources and environmental protection requirements. The residual substances in the purification tank (1) after treatment are pushed downward by gravity. When the discharge control valve (102) needs to be opened, the operator turns the connecting ring (18). The rotation of the connecting ring (18) drives the annular block (17) to move inward. The annular block (17) pushes the limiting ring (16) to slide in the sliding groove (13). The limiting ring (16) squeezes the spring (15), and the telescopic rod (14) contracts the auxiliary spring (15) to stabilize the deformation. At this time, the sealing gasket (19) separates from the sealing groove (20), and the residual material is discharged from the purification tank (1) through the discharge pipe (11), ensuring the stability of the internal environment of the purification tank (1) and maintaining the purification efficiency. When the gas at the three-way pipe (10) cannot be effectively recovered or needs to be discharged urgently, the gas pushes the valve disc of the first pressure control valve (103) to open and enter the flare connection pipe (12) for discharge, ensuring the safe operation of the entire device. The first pressure control valve (103) accurately controls the gas pressure discharged to the flare connection pipe (12) according to the actual production situation, avoiding safety accidents caused by excessive pressure, and at the same time reasonably adjusting the discharge gas volume to reduce unnecessary energy waste and environmental pollution.

[0036] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

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