Novel propylene recovery unit

Abstract

This utility model relates to a novel propylene gas recovery device in the field of gas recovery technology. It includes a connected propylene gas compressor, a water cooler, a precooler, a primary condenser, a secondary condenser, a separation membrane, a liquid storage tank, a primary refrigeration unit, and a secondary refrigeration unit. This device can significantly improve the utilization rate of propylene, reduce production costs, and minimize environmental impact. The recovered propylene can be directly reused in production (such as polypropylene and acrylonitrile), reducing the amount of propylene raw materials purchased. Simultaneously, the purified nitrogen can be used for purging or replacement gas, reducing enterprise production costs and improving economic efficiency. This device achieves zero emissions of waste gas, solving environmental problems such as waste gas emissions for enterprises, saving environmental protection investment, and contributing to sustainable development. The device operates fully automatically under PLC control, requiring no human intervention. It can automatically drain liquid and replenish gas, with the drained liquid being transported to a designated location via system pressure, eliminating the need for a drain pump.

Description

Technical Field

[0001] This utility model relates to the field of gas recovery technology, and in particular to a novel propylene gas recovery device. It recovers propylene and nitrogen by collecting, compressing, condensing, and separating propylene vapor emitted from polypropylene plants in petrochemical, fine chemical and other enterprises, thereby achieving energy conservation and emission reduction. Background Technology

[0002] Propylene is an important chemical raw material used in the production of polypropylene, acrylonitrile, butanol, octanol, propylene oxide, isopropanol, and acrylic acid, among other chemical products, and has wide applications in industrial production. Through propylene recovery technology, companies can achieve efficient utilization of propylene resources. This not only helps reduce production costs and improve economic efficiency but also reduces emissions, addresses environmental issues, and promotes green and sustainable development in the industry.

[0003] While some existing propylene gas recovery devices can recover most of the propylene gas, the heat, cold energy, and other waste gases generated during the recovery process cannot be fully utilized, resulting in resource waste and environmental pollution. Utility Model Content

[0004] The purpose of this invention is to provide a novel propylene gas recovery device. Propylene vapor generated by the polypropylene unit is pressurized to 2.0 MPaG by a propylene gas compressor, and then sent to the nitrogen pipeline network via a water cooler, precooler, condenser, and separation membrane. The entire device achieves the recovery and utilization of propylene and nitrogen, with zero waste gas emissions, improving propylene utilization while reducing enterprise production costs and minimizing environmental pollution.

[0005] This utility model relates to a novel propylene gas recovery device, including a propylene gas compressor, a water cooler, a precooler, a primary condenser, a secondary condenser, a separation membrane, a liquid storage tank, a primary refrigeration unit, and a secondary refrigeration unit. The water cooler is connected to the propylene gas compressor, and the water cooler can cool the compressed propylene gas. The primary refrigeration unit is connected to the primary condenser, and the primary refrigeration unit can cool the propylene gas in the primary condenser and recover some of the propylene. The secondary refrigeration unit is connected to the secondary condenser, and the secondary refrigeration unit can cool the propylene gas in the secondary condenser and recover most of the propylene. The precooler is connected to the water cooler. The precooler can exchange heat with the propylene gas sent out by the water cooler, recover and utilize part of the cooling capacity, and at the same time initially reduce the temperature of the propylene gas. The primary condenser is connected to the precooler, the secondary condenser, and the storage tank. The propylene condensed into liquid in the primary condenser is collected in the storage tank, and the uncondensed propylene gas enters the secondary condenser. The secondary condenser is connected to the precooler, the primary condenser, and the storage tank. The propylene condensed into liquid in the secondary condenser is collected in the storage tank, while the uncondensed propylene gas enters the precooler. The separation membrane is connected to the precooler and the propylene gas compressor respectively. The non-condensable gas sent out by the precooler is separated into two by the separation membrane. The membrane permeate side is the organic matter enrichment side, which is returned to the inlet of the propylene compressor for compression and cascade treatment. The permeate side is low-concentration propylene gas, which is directly discharged into the pipeline network.

[0006] To ensure the compression effect, as a preferred technical solution of this application, the propylene gas compressor is a reciprocating compressor with an outlet pressure of 2.0 MPa and an outlet temperature of ≤160℃.

[0007] To ensure heat exchange efficiency, as a preferred technical solution of this application, both the primary condenser and the secondary condenser are shell-and-tube heat exchangers, with the shell material being carbon steel and the heat exchange tube material being stainless steel.

[0008] To ensure the separation effect, as a preferred technical solution of this application, the separation membrane (6) is made of POMS material.

[0009] In order to ensure the cooling effect, as a preferred technical solution of this application, the refrigerant provided by the first-stage refrigeration unit (8) can cool the propylene gas to 0°C by flowing through the pipe, and the refrigerant provided by the second-stage refrigeration unit (9) can cool the propylene gas to -40°C by flowing through the pipe.

[0010] Compared with the prior art, this utility model has the following technical effects: (1) The propylene recovery compression and condensation technology of this device can significantly improve the utilization rate of propylene, reduce production costs, and reduce the impact on the environment. (2) The propylene recovered by this device can be directly reused in production (such as polypropylene, acrylonitrile, etc.), reducing the amount of propylene raw materials purchased. At the same time, the purified nitrogen can be used for purging or replacement gas, reducing the enterprise's production costs and improving economic benefits. (3) This device achieves zero emissions of waste gas, which can solve environmental problems such as waste gas emissions of enterprises, save enterprises' environmental protection investment, and help enterprises achieve sustainable development; (4) This device is fully automated and unattended by PLC control. It can realize functions such as automatic liquid drainage and gas replenishment. The liquid can be delivered to the designated location by the system pressure without the need for a liquid drainage pump. Attached Figure Description

[0011] Figure 1 This is a system schematic diagram of the novel propylene gas recovery device of this utility model. Detailed Implementation

[0012] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of the present invention.

[0013] like Figure 1 The novel propylene gas recovery device shown includes a propylene gas compressor 1, a water cooler 2, a precooler 3, a primary condenser 4, a secondary condenser 5, a separation membrane 6, a liquid storage tank 7, a primary refrigeration unit 8, and a secondary refrigeration unit 9.

[0014] Specifically, the propylene gas compressor 1 is a reciprocating compressor with an M-type, four-row, three-stage double-acting structure, an outlet pressure of 2.0 MPa, and an outlet temperature of ≤160℃.

[0015] Specifically, the water cooler 2 is connected to the propylene gas compressor 1. The water cooler 2 can cool down the compressed propylene gas. By exchanging heat between the cooling water and the high-temperature compressed propylene gas, the temperature of the propylene gas can be reduced to ≤45℃, reducing the cooling capacity of the subsequent condenser and improving the safety of the propylene gas.

[0016] Specifically, the precooler 3 is connected to the secondary condenser 5. In the precooler 3, propylene gas exchanges heat with the non-condensable gas that has been cooled to -40°C at the outlet of the secondary condenser 5, recovering and utilizing part of the cooling capacity. At the same time, it initially reduces the temperature of the propylene gas, reduces the cooling capacity of the subsequent condenser, and reduces power consumption.

[0017] Specifically, the primary condenser 4 is connected to the primary refrigeration unit 8, the precooler 3, the secondary condenser 5, and the liquid storage tank 7. The primary condenser 4 is a shell-and-tube heat exchanger with a shell made of carbon steel and heat exchange tubes made of stainless steel. The refrigerant provided by the primary refrigeration unit 8 flows through the tube side to cool the propylene gas to about 0°C, recovers some propylene, and collects the condensed liquid propylene in the liquid storage tank 7. The uncondensed propylene gas enters the secondary condenser 5.

[0018] Specifically, the secondary condenser 5 is connected to the primary condenser 4, the precooler 3, and the secondary refrigeration unit 9. The secondary condenser 5 is a shell-and-tube heat exchanger with a shell made of carbon steel and heat exchange tubes made of stainless steel. The refrigerant provided by the secondary refrigeration unit 9 flows through the tube side to cool the propylene gas to about -40°C, recovering most of the propylene. The propylene is condensed into liquid and collected in the storage tank 7. The uncondensed propylene gas first enters the precooler 3 and then enters the separation membrane 6 for further separation.

[0019] Specifically, the separation membrane 6 is connected to the precooler 3 and the propylene gas compressor 1, respectively, and the separation membrane 6 is made of POMS material. Non-condensable gas passes through the separation membrane 6 and is split into two. The membrane permeate side is the organic matter enrichment side, which is returned to the inlet of the propylene gas compressor 1 for compression and cascade treatment. The nitrogen purity of the gas on the interception side is ≥99%, and it is sent to the nitrogen pipeline network in the equipment boundary area.

[0020] Specifically, the liquid storage tank 7 is connected to the primary condenser 4 and the secondary condenser 5 respectively. The liquid storage tank 7 is a horizontal storage tank with an oil inlet at the top, an oil outlet and a sludge outlet at the bottom, and a liquid level gauge installed on the side. Propylene is automatically discharged according to the liquid level through a system pressure of 2.0 MPaG.

[0021] Specifically, the cooling capacity of the primary condenser 4 is provided by the primary refrigeration unit 8. The propylene gas is condensed to 0°C in the primary condenser 4, and the condensed liquid enters the liquid storage tank 7. The uncondensed propylene gas enters the secondary condenser 5.

[0022] Specifically, the cooling capacity of the secondary condenser 5 is provided by the secondary refrigeration unit 9. The propylene gas is condensed to -40°C in the secondary condenser 5, and the condensed liquid enters the storage tank 7. The uncondensed propylene gas first enters the precooler 3 and then enters the separation membrane 6 for further separation.

[0023] When the equipment is running, the propylene gas compressor 1 automatically starts according to the inlet gas pressure and adjusts the propylene gas flow rate by frequency conversion. The propylene gas compressed by the propylene gas compressor 1 enters the water cooler 2.

[0024] The propylene gas then sequentially enters precooler 3, primary condenser 4 (the cooling capacity required for primary condenser 4 is provided by primary refrigeration unit 8), and secondary condenser 5 (the cooling capacity required for secondary condenser 5 is provided by secondary refrigeration unit 9). In precooler 3, the propylene gas exchanges heat with the previously cooled non-condensable gas to -40°C, recovering some of the cooling capacity and initially lowering the temperature of the propylene gas before entering primary condenser 4 for more efficient energy utilization and reduced energy consumption. In primary condenser 4, the temperature of the propylene gas drops to around 0°C. The non-condensed propylene gas enters secondary condenser 5, where the temperature continues to drop to around -40°C. At this point, most of the components condense into liquid and are collected in storage tank 7, then transported to a designated location under system pressure. A small amount of non-condensed propylene gas enters separation membrane unit 6.

[0025] Non-condensable vapor passes through separation membrane 6 and is split into two. The membrane permeate side is the organic matter enrichment side and returns to the inlet of propylene gas compressor 1 for compression and cascade treatment. The nitrogen purity of the gas on the interception side is ≥99% and is sent to the equipment nitrogen pipeline network.

[0026] It should be noted that the parts not covered by this utility model are the same as or can be implemented using existing technology.

[0027] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A novel propylene gas recovery device, characterized in that: It includes a propylene gas compressor (1), a water cooler (2), a precooler (3), a primary condenser (4), a secondary condenser (5), a separation membrane (6), a liquid storage tank (7), a primary refrigeration unit (8), and a secondary refrigeration unit (9). The water cooler (2) is connected to the propylene gas compressor (1), and the water cooler (2) can cool down the compressed propylene gas. The primary refrigeration unit (8) is connected to the primary condenser (4). The primary refrigeration unit (8) can cool down the propylene gas in the primary condenser (4) and recover some of the propylene. The secondary refrigeration unit (9) is connected to the secondary condenser (5). The secondary refrigeration unit (9) can cool down the propylene gas in the secondary condenser (5) and recover most of the propylene. The precooler (3) is connected to the water cooler (2). The precooler (3) can exchange heat with the propylene gas sent out by the water cooler (2), recover and utilize part of the cold energy, and at the same time initially reduce the temperature of the propylene gas. The first-stage condenser (4) is connected to the precooler (3), the second-stage condenser (5), and the liquid storage tank (7) respectively. The propylene condensed into liquid in the first-stage condenser (4) is collected in the liquid storage tank (7), and the uncondensed propylene gas enters the second-stage condenser (5). The secondary condenser (5) is connected to the precooler (3), the primary condenser (4), and the storage tank (7) respectively. The propylene condensed into liquid in the secondary condenser (5) is collected in the storage tank (7), and the uncondensed propylene gas enters the precooler (3). The separation membrane (6) is connected to the precooler (3) and the propylene gas compressor (1) respectively. The non-condensable gas sent out by the precooler (3) is separated into two by the separation membrane (6). The membrane permeate side is the organic matter enrichment side, which is returned to the inlet of the propylene gas compressor (1) for compression and superposition treatment. The permeate side is low-concentration propylene gas, which is directly discharged into the pipeline network.

2. The novel propylene gas recovery device according to claim 1, characterized in that: The propylene gas compressor (1) is a reciprocating compressor with an outlet pressure of 2.0 MPa and an outlet temperature of ≤160℃.

3. The novel propylene gas recovery device according to claim 1, characterized in that: Both the primary condenser (4) and the secondary condenser (5) are shell-and-tube heat exchangers, with the shell material being carbon steel and the heat exchange tube material being stainless steel.

4. The novel propylene gas recovery device according to claim 1, characterized in that: The separation membrane (6) is made of POMS material.

5. The novel propylene gas recovery device according to claim 1, characterized in that: The refrigerant provided by the primary refrigeration unit (8) can cool the propylene gas to 0°C by flowing through the pipes, and the refrigerant provided by the secondary refrigeration unit (9) can cool the propylene gas to -40°C by flowing through the pipes.

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