Propylene vaporization preheating system with separation function in acrylic acid production

Abstract

The utility model belongs to the technical field of acrylic acid production devices, and particularly relates to a propylene vaporization preheating system with a separation function in acrylic acid production. The propylene vaporization preheating system with the separation function in acrylic acid production comprises a propylene vaporization device, the propylene vaporization device is connected with a propylene buffer degassing tank, and a degassing tank safety valve is arranged at the top of the propylene buffer degassing tank; a demister is arranged on the propylene vaporization device, the demister is connected with a propylene heater through a propylene gas phase pipeline, and the propylene heater is provided with a pipeline connected with a downstream device. According to the propylene vaporization preheating system with the separation function in the acrylic acid production, low-temperature water and steam are adopted to realize vaporization and preheating of propylene, and a propylene buffer degassing tank is matched, so that the operation stability of the whole system in the propylene vaporization stage is ensured; the demister is arranged in the propylene vaporization device, so that pipeline vibration caused by gas-liquid mixed conveying is avoided, and the safety of the system is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of acrylic acid production devices, and in particular relates to a propylene vaporization preheating system with a separation function in acrylic acid production. Background Art

[0002] As an important chemical raw material, the industrial production of acrylic acid mainly relies on the propylene oxidation method, which converts propylene into acrylic acid through a two-step fixed-bed catalytic oxidation process. Among them, the physical properties of propylene (the boiling point is -47.7°C under normal pressure) determine that it needs to be stored and transported in a liquid pressurized form. Therefore, the stability of the propylene vaporization process is a key link in the front end of the process, which directly affects the subsequent reaction efficiency and system operation.

[0003] CN222468993U discloses an acrylic acid oxidation device, in which, during the propylene vaporization process, only a propylene evaporator is used to complete the vaporization process, so that liquid propylene is converted into gas and enters a mixer to participate in subsequent reactions, but the generated gaseous propylene is not further separated, and the stability of gaseous propylene transportation cannot be guaranteed. In addition, during the propylene vaporization process, pressure control is adopted. Under abnormal pressure conditions, liquid propylene will break through the dynamic balance and directly enter the gas outlet, and the stable operation of the device cannot be achieved.

[0004] CN222400349U discloses a low-temperature gas-liquid separator. By arranging a separation chamber, an air outlet pipe and a liquid outlet pipe inside the shell, the design has the advantages of simplified structure and low manufacturing cost. The bending structure of the separation section can adapt to deformation. The separation hole and the filter component are combined to achieve efficient separation of droplets with a diameter of ≥200μm, and the vacuum layer ensures the reliability of thermal insulation. However, there are the inconveniences that the separation hole is easy to be blocked and the shell needs to be disassembled for maintenance, and the separation ability of ultrafine droplets is limited, which needs to rely on subsequent process supplementary treatment. Overall, the separator has practical value in balancing cost and performance in industrial low-temperature scenarios, and is suitable for working conditions with high requirements for medium cleanliness. Utility Model Content

[0005] The utility model aims to overcome the defects of the prior art and provide a propylene vaporization and preheating system with a separation function in acrylic acid production. The system adopts low-temperature water and steam to realize the vaporization and preheating of propylene, and cooperates with a propylene buffer degassing tank to ensure the stability of the overall system operation in the propylene vaporization stage. A demister is arranged in the propylene vaporization device, and its internal structure is designed to realize rapid separation of gas and liquid, avoid pipeline vibration caused by gas-liquid mixed transportation, and ensure the safety of the system.

[0006] The utility model discloses a propylene vaporization preheating system with a separation function in acrylic acid production, comprising a propylene vaporization device, wherein the propylene vaporization device is provided with a pipeline connected with a propylene buffer degassing tank, a regulating valve is provided on the pipeline, the propylene buffer degassing tank is connected with a raw material tank, a degassing tank safety valve is provided on the top of the propylene buffer degassing tank, and the degassing tank safety valve is provided with a pipeline connected with a flare system; a propylene heat exchanger is provided in the propylene vaporization device, and the propylene heat exchanger is used for heating propylene to vaporize it; a demister is provided on the propylene vaporization device, and the demister is connected with a propylene heater through a propylene gas phase pipeline; the propylene heater is provided with a pipeline connected with a downstream device, and a vaporized propylene thermometer is provided on the pipeline.

[0007] Preferably, a baffle and a separation plate are sequentially arranged inside the demister from bottom to top, the baffle being composed of an external baffle and a central wire mesh, and the central wire mesh is fixed on the baffle; the separation plate being composed of a wire mesh grid and a wire mesh, and the wire mesh is fixed on the wire mesh grid; wherein the external baffle plays a guiding role, and the gas phase propylene carrying a trace amount of liquid phase collides with the baffle to achieve preliminary gas-liquid separation.

[0008] Preferably, the propylene vaporizer is provided with a vaporizer liquid level gauge, the top of the propylene vaporizer is provided with a vaporizer safety valve and a pressure gauge, and the vaporizer safety valve is connected to the flare system through a pipeline.

[0009] Preferably, the inlet of the propylene vaporizing heat exchanger is connected to the outlet of the circulating pump through a low-temperature water inlet pipeline, the low-temperature water inlet pipeline is provided with an inlet regulating valve and an inlet thermometer, the low-temperature water inlet pipeline is connected in parallel with the hot water pipeline, and the hot water pipeline is provided with a hot water regulating valve; the outlet of the propylene vaporizing heat exchanger is connected to the low-temperature water return pipeline; further, the joint of the low-temperature water inlet pipeline and the hot water pipeline is located in front of the inlet thermometer.

[0010] Preferably, the demister is connected to a nitrogen pipeline, a nitrogen regulating valve is provided on the nitrogen pipeline, and a gas-phase propylene regulating valve is provided on the propylene gas-phase pipeline.

[0011] Preferably, the propylene heater is a sleeve heater, which adopts a concentric sleeve countercurrent heat exchange method, with propylene introduced into the tube side and heat medium steam introduced into the shell side; the shell side is provided with a pipeline connected to the steam system near the propylene outlet side, and a steam regulating valve is provided on the pipeline; the shell side is provided with a condensate pipeline near the propylene inlet side for discharging steam condensate generated during the heat exchange process.

[0012] Preferably, a pipeline for reflux to the inlet of the propylene heater is provided at the outlet of the propylene heater, and a propylene reflux regulating valve is provided on the pipeline.

[0013] Specifically, the propylene vaporization preheating system with separation function in acrylic acid production has the following working process: propylene from the raw material tank enters the propylene buffer gas remover, which can buffer the pipeline vibration problem caused by vaporization during propylene transportation. For example, during the transportation process, a small amount of gaseous propylene is generated due to temperature difference or pressure fluctuation, which can be discharged to the flare system through the gas remover safety valve for safe combustion; after the liquid propylene passes through the propylene buffer gas remover, it enters the propylene vaporization device through the control of the regulating valve, and forms a control loop through the regulating valve and the vaporization device liquid level gauge on the propylene vaporization device to perform liquid level automatic control; after entering the propylene vaporization device, the propylene is heated in the propylene vaporization heat exchanger. , it gradually vaporizes under the action of; in the propylene vaporizing heat exchanger, the heat exchange medium is 5℃ low-temperature water. The low-temperature water from the device is pressurized by the circulating pump and enters the propylene vaporizing heat exchanger to exchange heat with the liquid propylene in the propylene vaporizing device. When the temperature is low in winter, in order to ensure the stability of propylene vaporization, the water temperature entering the propylene vaporizing heat exchanger is controlled by the hot water regulating valve to be maintained at 5℃. The water temperature is displayed by the inlet thermometer. The low-temperature water after heat exchange is circulated to other devices through the low-temperature water return pipeline. The amount of water entering the propylene vaporizing heat exchanger depends on the propylene pressure in the propylene vaporizing device. The low-temperature water inlet amount is adjusted according to the pressure control requirements of the pressure gauge on the propylene vaporizing device.

[0014] The propylene vaporization and evaporation in the propylene vaporization device is controlled by low-temperature water. The vaporized propylene passes through the baffle and separation plate in the demister and then enters the propylene heater. In the demister, the incompletely vaporized propylene entrained by the gas phase propylene is intercepted and returned to the propylene vaporization device. The propylene heater uses high-temperature steam as a heat medium. The temperature of the vaporized propylene is controlled by the size of the steam regulating valve to meet the process requirements and enter the downstream device for reaction. If the gas phase propylene that does not meet the temperature is produced, it can be transported to the inlet of the propylene heater through the reflux pipeline and reheated to ensure that the gas phase propylene produced by this system meets the process requirements. After heat exchange, the condensate produced by the steam is discharged through the condensate pipeline. Secondly, the propylene vaporization device is equipped with a vaporization device safety valve. When an abnormal situation occurs and the propylene vaporization is overpressured, the vaporization device safety valve is activated, and the overpressure vaporized propylene is discharged to the flare system for safe combustion. At the same time, the gas phase propylene regulating valve is closed to cut off the propylene transmission path, and the nitrogen regulating valve is opened. The high-pressure nitrogen countercurrent passes through the demister and enters the propylene vaporization device to ensure the safety of the entire system. High-pressure nitrogen only enters the system when the pressure is abnormal.

[0015] Compared with the prior art, the utility model has the following beneficial effects: the linkage design of the propylene buffer degassing tank, the safety valve of the vaporization device and the nitrogen pipeline can be used to safely discharge and maintain the system pressure balance through the flare system when the pressure is abnormal, thereby effectively suppressing the risk of propylene self-polymerization; propylene is vaporized by low-temperature water, and the gas phase propylene is heated by steam, and the unvaporized liquid droplets are intercepted by the demister, thereby realizing a rapid gas-liquid separation process and ensuring the stability of the subsequent reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a propylene vaporization preheating system with separation function in acrylic acid production of the utility model;

[0017] Figure 2 It is a structural schematic diagram of the demister in the utility model;

[0018] Figure 3 It is a structural schematic diagram of the baffle in the utility model;

[0019] Figure 4 It is a structural schematic diagram of the separation plate in the utility model.

[0020] In the figure: 1. Propylene buffer degassing tank; 2. Degassing tank safety valve; 3. Regulating valve; 4. Vaporization device liquid level gauge; 5. Propylene vaporization device; 6. Propylene vaporization heat exchanger; 7. Circulating pump; 8. Hot water regulating valve; 9. Inlet water thermometer; 10. Low-temperature water return pipe; 11. Inlet regulating valve; 12. Pressure gauge; 13. Defoamer; 1301. Baffle; 1302. Separation plate; 1303. Baffle; 1304. Wire mesh; 1305 , wire mesh grid; 14, propylene gas phase pipeline; 15, propylene heater; 16, steam regulating valve; 17, vaporized propylene thermometer; 18, vaporization device safety valve; 19, nitrogen pipeline; 20, condensate pipeline; 21, flare system; 22, raw material tank; 23, hot water pipeline; 24, low-temperature water inlet pipeline; 25, steam system; 26, downstream device; 27, propylene reflux regulating valve; 28, gas-phase propylene regulating valve; 29, nitrogen regulating valve. DETAILED DESCRIPTION

[0021] The specific technical scheme of the utility model will be further described below in conjunction with the accompanying drawings.

[0022] like Figure 1-Figure 4 As shown, the propylene vaporization preheating system with separation function in acrylic acid production comprises a propylene buffer degassing tank 1, a propylene vaporization device 5, and a propylene heater 15. The propylene buffer degassing tank 1 is connected to the propylene vaporization device 5 by a pipeline, and a regulating valve 3 is arranged on the pipeline; a propylene vaporization heat exchanger 6 is arranged in the propylene vaporization device 5, and a demister 13 is arranged on the top of the propylene vaporization device 5; the demister 13 is connected to the propylene heater 15 through a propylene gas phase pipeline 14, and the propylene heater 15 is provided with a pipeline connected to a downstream device 26, and a vaporized propylene thermometer 17 is arranged on the pipeline.

[0023] The defoamer 13 is provided with a baffle 1301 and a separation plate 1302 from bottom to top in sequence. The baffle 1301 is composed of an external baffle 1303 and a central wire mesh 1304, and the central wire mesh 1304 is fixed on the baffle 1303; the separation plate 1302 is composed of a wire mesh grille 1305 and a wire mesh 1304, and the wire mesh 1304 is fixed on the wire mesh grille 1305.

[0024] The propylene buffer degassing tank 1 is connected to the propylene raw material tank 22 , a degassing tank safety valve 2 is arranged on the top of the propylene buffer degassing tank 1 , and the degassing tank safety valve 2 is connected to the flare system 21 through a pipeline.

[0025] The propylene vaporizer 5 is provided with a vaporizer liquid level gauge 4, and the top of the propylene vaporizer 5 is provided with a vaporizer safety valve 18 and a pressure gauge 12, and the vaporizer safety valve 18 is connected to the flare system 21 through a pipeline.

[0026] The inlet of the propylene vaporizing heat exchanger 6 is connected to the outlet of the circulating pump 7 through a low-temperature water inlet pipeline 24, on which an inlet regulating valve 11 and an inlet thermometer 9 are provided. The low-temperature water inlet pipeline 24 is connected in parallel with a hot water pipeline 23, on which a hot water regulating valve 8 is provided; the outlet of the propylene vaporizing heat exchanger 6 is connected to a low-temperature water return pipeline 10.

[0027] The demister 13 is connected to a nitrogen pipeline 19 , a nitrogen regulating valve 29 is provided on the nitrogen pipeline 19 , and a gas-phase propylene regulating valve 28 is provided on the propylene gas-phase pipeline 14 .

[0028] The propylene heater 15 is a shell-and-tube heater, which adopts a concentric shell-and-tube countercurrent heat exchange method, with propylene introduced into the tube side and heat medium steam introduced into the shell side; the shell side is provided with a pipeline connected to the steam system 25 near the propylene outlet side, and a steam regulating valve 16 is provided on the pipeline; the shell side is provided with a condensate pipeline 20 near the propylene inlet side for discharging steam condensate generated during the heat exchange process.

[0029] A pipeline for reflux to the inlet of the propylene heater 15 is arranged at the outlet of the propylene heater 15 , and a propylene reflux regulating valve 27 is arranged on the pipeline.

[0030] The propylene vaporization preheating system with separation function in the above acrylic acid production has the following working process: propylene from the raw material tank 22 enters the propylene buffer gas remover 1, which can buffer the pipeline vibration problem caused by vaporization during the propylene transportation process. For example, during the transportation process, a small amount of gaseous propylene is generated due to temperature difference or pressure fluctuation, which can be discharged to the flare system 21 through the gas remover safety valve 2 for safe combustion; after the liquid propylene passes through the propylene buffer gas remover 1, it enters the propylene vaporization device 5 through the control of the regulating valve 3, and forms a control loop through the regulating valve 3 and the vaporization device liquid level meter 4 on the propylene vaporization device 5 to perform liquid level automatic control; after entering the propylene vaporization device 5, the propylene is heated by the propylene vaporization heat exchanger 6, Gradually vaporizes; in the propylene vaporizing heat exchanger 6, the heat exchange medium is 5°C low-temperature water. The low-temperature water from the device is pressurized by the circulating pump 7 and enters the propylene vaporizing heat exchanger 6, and exchanges heat with the liquid propylene in the propylene vaporizing device 5. When the temperature is low in winter, in order to ensure the stability of propylene vaporization, the water temperature entering the propylene vaporizing heat exchanger 6 is controlled by the hot water regulating valve 8 to be maintained at 5°C. The water temperature is displayed by the water inlet thermometer 9. The low-temperature water after heat exchange is circulated to other devices through the low-temperature water return pipeline 10. The amount of water entering the propylene vaporizing heat exchanger 6 depends on the propylene pressure in the propylene vaporizing device 5. According to the pressure control requirements of the pressure gauge 12 on the propylene vaporizing device 5, the water amount of the low-temperature water inlet pipeline 24 is adjusted.

[0031] The propylene is vaporized and evaporated in the propylene vaporization device 5 by controlling low-temperature water. The vaporized propylene enters the propylene heater 15 after passing through the demister 13. In the demister 13, the incompletely vaporized propylene entrained in the gaseous propylene is intercepted by the baffle 1301 and the separation plate 1302 arranged in the demister 13, and returns to the propylene vaporization device 5 to continue vaporization; the propylene heater 15 uses the high-temperature steam system 25 as a heat medium, and controls the temperature of the vaporized propylene to meet the process requirements through the size of the steam regulating valve 16, and enters the downstream device for reaction. If the gaseous propylene that does not meet the temperature is generated, it can be transported to the inlet of the propylene heater 15 through the reflux pipeline and reheated to ensure that the gaseous propylene generated by this system meets the process requirements; after heat exchange, the condensate generated by the steam is discharged through the condensate pipeline 20. Secondly, the propylene vaporizer 5 is equipped with a vaporizer safety valve 18. When an abnormal situation occurs and the propylene vaporizes overpressure, the vaporizer safety valve 18 is activated, and the overpressure vaporized propylene is discharged to the flare system 21 for safe combustion. At the same time, the gas phase propylene regulating valve 28 is closed to cut off the propylene delivery path, and the nitrogen regulating valve 29 is opened, and the high-pressure nitrogen countercurrently passes through the demister 13 into the propylene vaporizer 5 to ensure the safety of the entire system.

Claims

1. A propylene vaporization preheating system with separation function in acrylic acid production, characterized in that: The invention comprises a propylene buffer degassing tank (1), a propylene vaporizing device (5), and a propylene heater (15); the propylene buffer degassing tank (1) is connected to the propylene vaporizing device (5) via a pipeline, and a regulating valve (3) is arranged on the pipeline; a propylene vaporizing heat exchanger (6) is arranged in the propylene vaporizing device (5), and a demister (13) is arranged on the top of the propylene vaporizing device (5); the demister (13) is connected to the propylene heater (15) via a propylene gas phase pipeline (14); the propylene heater (15) is provided with a pipeline connected to a downstream device (26), and a vaporized propylene thermometer (17) is arranged on the pipeline.

2. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The demister (13) is provided with a baffle (1301) and a separation plate (1302) in sequence from bottom to top. The baffle (1301) is composed of an external baffle plate (1303) and a central wire mesh (1304), and the central wire mesh (1304) is fixed on the baffle plate (1303); the separation plate (1302) is composed of a wire mesh grille (1305) and a wire mesh (1304), and the wire mesh (1304) is fixed on the wire mesh grille (1305).

3. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The propylene buffer degassing tank (1) is connected to the propylene raw material tank (22), a degassing tank safety valve (2) is arranged on the top of the propylene buffer degassing tank (1), and the degassing tank safety valve (2) is connected to the flare system (21) through a pipeline.

4. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The propylene vaporizer (5) is provided with a vaporizer liquid level gauge (4), and the top of the propylene vaporizer (5) is provided with a vaporizer safety valve (18) and a pressure gauge (12), and the vaporizer safety valve (18) is connected to the flare system (21) via a pipeline.

5. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The inlet of the propylene vaporizing heat exchanger (6) is connected to the outlet of the circulation pump (7) via a low-temperature water inlet pipeline (24); a water inlet regulating valve (11) and a water inlet thermometer (9) are provided on the low-temperature water inlet pipeline (24); the low-temperature water inlet pipeline (24) is connected in parallel to a hot water pipeline (23); a hot water regulating valve (8) is provided on the hot water pipeline (23); and the outlet of the propylene vaporizing heat exchanger (6) is connected to a low-temperature water return pipeline (10).

6. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The demister (13) is connected to a nitrogen pipeline (19), a nitrogen regulating valve (29) is provided on the nitrogen pipeline (19), and a gas-phase propylene regulating valve (28) is provided on the propylene gas-phase pipeline (14).

7. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: The propylene heater (15) is a tube heater, which adopts a concentric tube countercurrent heat exchange method, with propylene introduced into the tube side and heat medium steam introduced into the shell side; the shell side is provided with a pipeline connected to the steam system (25) near the propylene outlet side, and a steam regulating valve (16) is provided on the pipeline; the shell side is provided with a condensate pipeline (20) near the propylene inlet side for discharging steam condensate generated during the heat exchange process.

8. The propylene vaporization and preheating system with separation function in acrylic acid production according to claim 1, characterized in that: A pipeline for reflux to the inlet of the propylene heater (15) is provided at the outlet of the propylene heater (15), and a propylene reflux regulating valve (27) is provided on the pipeline.

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