A liquid-phase propylene recovery device

Abstract

The present invention discloses a liquid-phase propylene recovery device, belonging to the technical field of chemical equipment. A liquid-phase propylene recovery device includes a propylene refrigeration compressor for providing propylene refrigerants of different temperature grades, and is characterized in that: a pipeline 1 is led out from the propylene refrigeration compressor to a first heat exchanger, a pipeline 2 is led out from the first heat exchanger, the pipeline 2 leads out a first branch pipeline and a second branch pipeline, the first branch pipeline is connected to the liquid-phase propylene unit, the second branch pipeline is connected to the gas-phase propylene unit, a second heat exchanger is connected to a steam inlet pipeline and a steam outlet pipeline which are communicated, the first heat exchanger and the second heat exchanger are installed in the housing, a methanol pipeline is connected to the housing, a liquid-phase propylene pipeline is led out between the propylene refrigeration compressor and a gate valve 5, and a pipeline 4 is led out from the pipeline 2 to a flare. The technical problems of liquid-phase propylene recovery of different temperature grades and the difficulty in the initial startup of the propylene refrigeration compressor are solved, and it is mainly applied to the aspect of propylene recovery and treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical equipment, and particularly relates to a liquid-phase propylene recovery device. Background Art

[0002] In domestic ethylene plants, a propylene refrigeration compressor is essential. Depending on the characteristics of different production processes, the degree of association between the propylene refrigeration compressor and the system varies. Usually, the propylene system used is the largest in capacity and at the end of the process in the ethylene plant. Therefore, when the propylene system is shut down, a large amount of propylene stagnates in the system. During the normal operation of the propylene refrigeration compressor, propylene refrigerants of different temperature grades are provided according to different users, namely -40°C, -20°C, -6°C, and 10°C. Because the temperature span is large, recovering these propylenes simultaneously will lead to a complex process. Moreover, there are multiple processes involved in the original start-up process of propylene, mainly including: nitrogen replacement, actual gas replacement with gaseous propylene, pressurization with gaseous propylene, and filling with liquid-phase propylene, etc. Therefore, in the case of purchasing liquid-phase propylene, a dedicated propylene vaporizer needs to be equipped in the chemical industrial park to vaporize the liquid-phase propylene to meet the original start-up requirements of the propylene refrigeration compressor;

[0003] However, the currently used propylene vaporizer has the following disadvantages: 1. The heat source of the vaporizer is in direct contact with the liquid-phase propylene, resulting in uneven heating of the propylene; 2. The vaporizer cannot recover low-temperature liquid-phase propylene of different temperature grades; 3. The temperature and pressure stability of the gas phase at the outlet of the vaporizer is poor; 4. It is impossible to ensure complete vaporization of the liquid-phase propylene. Therefore, how to meet the initial start-up requirements of the propylene refrigeration compressor and recover the liquid-phase propylene refrigerants of different temperature grades in the system with only the supply of liquid-phase propylene has become an urgent technical problem to be solved. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a liquid-phase propylene recovery device to solve the technical problems of recovering liquid-phase propylene of different temperature grades and the initial start-up of the propylene refrigeration compressor.

[0005] A liquid-phase propylene recovery device, comprising:

[0006] A propylene refrigeration compressor, which is used to provide propylene refrigerants of different temperature grades;

[0007] Characterized in that: a first heat exchanger, a pipeline one is led out from the propylene refrigeration compressor to the first heat exchanger, and a pipeline two is led out from the first heat exchanger. The pipeline two leads out a first branch pipeline and a second branch pipeline. A gate valve one is installed on the first branch pipeline and connected to the liquid-phase propylene unit, and a gate valve two is installed on the second branch pipeline and connected to the gas-phase propylene unit;

[0008] A second heat exchanger, which is connected to a steam inlet pipeline and a steam outlet pipeline that are in communication, and a gate valve three and a check valve one are installed along the steam inlet pipeline;

[0009] A housing, where the first heat exchanger and the second heat exchanger are installed in the housing, and a methanol pipeline is connected to the housing, and a gate valve four and a check valve two are installed along the methanol pipeline in sequence;

[0010] A pipeline one, where a gate valve five, a check valve three, a pressure gauge one, a thermometer one and a gate valve six are installed along the pipeline one in sequence, and a pipeline three is led out to a pipeline two between the thermometer one and the gate valve six, a gate valve seven is installed on the pipeline three, and a liquid-phase propylene pipeline is led out between the propylene refrigeration compressor and the gate valve five, and a gate valve nine is installed on the liquid-phase propylene pipeline;

[0011] A pipeline two, where a thermometer two, a pressure gauge two, a check valve four and a gate valve eight are installed along the pipeline two;

[0012] A flare, and a pipeline four is led out from the pipeline two to the flare.

[0013] Furthermore: A pipeline five is led out from the housing to the flare, and after stopping operation, the methanol in the housing is discharged to the flare for combustion.

[0014] Furthermore: A pressure gauge three and a remote transmission liquid level gauge are installed on the housing. The methanol liquid level in the housing is viewed through the remote transmission liquid level gauge, and the pressure gauge three detects the methanol saturation pressure in the housing, so as to adjust the low-pressure steam inlet volume.

[0015] Compared with the prior art, the present invention has the following advantages: The present invention heats the methanol in the housing, and then indirectly heats the liquid-phase propylene with the heated methanol, making the propylene heat more evenly. At the same time, the present invention uses the pressure gauge three to monitor the methanol saturation pressure, and adjusts the low-pressure steam inlet volume according to the control of the methanol saturation pressure, thereby achieving the purpose of adjusting the methanol temperature and controlling the liquefaction or gasification of propylene. In summary, the vaporizer provided by this application is composed of a first heat exchanger and a second heat exchanger installed in the housing. By adopting the technical solution of this application, the gas-phase propylene demand for the initial start-up of the propylene refrigeration compressor is provided in the state of only having liquid-phase propylene. The technical solution provided by the present invention controls the temperature of methanol through the pressure gauge three when recovering propylene in the propylene refrigeration compressor, realizing that during the liquid-phase propylene recovery process, the liquid-phase propylene with different temperature grades can be heated to above-zero liquid-phase recovery, or the liquid-phase propylene can be gasified to supply gas-phase propylene by increasing the steam inlet volume to increase the methanol temperature. Since the whole structure is more reasonable, the production cost is lower, and it is suitable for comprehensive promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a liquid-phase propylene recovery device of the present invention. Detailed implementation mode

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0018] In the description of the invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Embodiment 1:

[0019] A liquid-phase propylene recovery device, comprising:

[0020] A propylene refrigeration compressor 1, and the propylene refrigeration compressor 1 is used to provide propylene refrigerants of different temperature grades;

[0021] It is characterized in that: a first heat exchanger 2, a pipeline 1 is led out from the propylene refrigeration compressor 1 to the first heat exchanger 2, and a pipeline 2 is led out from the first heat exchanger 2. A first branch pipeline 5 and a second branch pipeline 6 are led out from the pipeline 2. A gate valve 1 is installed on the first branch pipeline 5 and is connected to a liquid-phase propylene unit 2, and a gate valve 2 is installed on the second branch pipeline 6 and is connected to a gas-phase propylene unit 2;

[0022] A second heat exchanger 7, and the second heat exchanger 7 is connected to a steam inlet pipeline 8 and a steam outlet pipeline 9 that are in communication. A gate valve 3 and a check valve 1 are installed along the steam inlet pipeline 8;

[0023] A housing 10, the first heat exchanger 2 and the second heat exchanger 7 are installed in the housing 10, and a methanol pipeline 11 is connected to the housing 10. A gate valve 4 and a check valve 2 are installed in sequence along the methanol pipeline 11;

[0024] Pipeline 1 - 3, a gate valve five 31, a check valve three 32, a pressure gauge one 33, a thermometer one 34, and a gate valve six 35 are installed in sequence along the pipeline 1 - 3. A pipeline three 14 is led out between the thermometer one 34 and the gate valve six 35 to the pipeline two 4. A gate valve seven 15 is installed on the pipeline three 14. A liquid phase propylene pipeline 21 is led out between the propylene refrigeration compressor 1 and the gate valve five 31, and a gate valve nine 22 is installed on the liquid phase propylene pipeline 21;

[0025] Pipeline two 4, a thermometer two 41, a pressure gauge two 42, a check valve four 43, and a gate valve eight 44 are installed along the pipeline two 4;

[0026] Torch 16, a pipeline four 17 is led out from the pipeline two 4 to the torch 16.

[0027] A pipeline five 18 is led out from the housing 10 to the torch 16. After stopping operation, the methanol in the housing is drained to the torch for combustion.

[0028] A pressure gauge three 19 and a remote - transmission liquid level gauge 20 are installed on the housing 10. The liquid level of methanol in the housing is determined by the remote - transmission liquid level gauge, and the pressure gauge three detects the saturated pressure of methanol in the housing to adjust the low - pressure steam inlet volume.

[0029] The first embodiment of the present invention: Before starting the propylene refrigeration compressor, the gate valve one 51 and the gate valve seven 15 are closed. Liquid phase propylene is connected from outside the plant to the liquid phase propylene pipeline 21 and then enters the pipeline 1 - 3 through the gate valve nine 22. After entering the pipeline 1 - 3, the liquid phase propylene passes through the gate valve five 31, the check valve three 32, the pressure gauge one 33, the thermometer one 34, and the gate valve six 35 in sequence and then enters the first heat exchanger 2. Low - pressure steam enters the second heat exchanger 7 from the steam inlet pipeline through the gate valve three 81 and the check valve one 82 in sequence. Methanol enters the housing 10 from the outside through the methanol pipeline 11 and then passes through the gate valve four 12 and the check valve two 13 in sequence. The low - pressure steam in the second heat exchanger 7 indirectly heats the methanol in the housing 10. After heating, the methanol heats and vaporizes the liquid phase propylene in the first heat exchanger 2. The vaporized propylene gas enters the pipeline two 4 and passes through the thermometer two 41, the pressure gauge two 42, the check valve four 43, and the gate valve eight 44 in sequence and then is sent to the second branch pipeline 6. The propylene gas entering the second branch pipeline 6 enters the gas - phase propylene unit 62 through the gate valve two 61 for supply and use;

[0030] The second embodiment of the present invention: Before starting the propylene refrigeration compressor, the gate valve six 35, the gate valve eight 44, and the gate valve two 61 are closed. Liquid phase propylene is connected from the outside to the liquid phase propylene pipeline 21 and enters the pipeline 1 - 3 through the gate valve nine 22. The liquid phase propylene passes through the gate valve five 31, the check valve three 32, the pressure gauge one 33, and the thermometer one 34 in sequence in the pipeline 1 - 3 and then enters the pipeline three 14. The liquid phase propylene then enters the pipeline two 4 through the gate valve seven 15 and then enters the liquid - phase propylene unit 52 through the gate valve one 51 for supply to liquid - phase users;

[0031] The third embodiment of the present invention: When the liquid-phase propylene level in the system is high and needs to be discharged during the normal operation of the propylene refrigeration compressor, close gate valve nine 22, gate valve seven 15, and gate valve one 51. The liquid-phase propylene enters pipeline one 3 from the propylene refrigeration compressor 1. The liquid-phase propylene in pipeline one 3 sequentially passes through gate valve five 31, check valve three 32, pressure gauge one 33, thermometer one 34, and gate valve six 35 and then enters the first heat exchanger 2. At the same time, the low-pressure steam enters the second heat exchanger 7 from the steam inlet pipeline sequentially through gate valve three 81 and check valve one 82. Methanol enters the methanol pipeline 11 from the outside and then sequentially passes through gate valve four 12 and check valve two 13 and enters the housing 10. The low-pressure steam enters the second heat exchanger 7 to indirectly heat the methanol in the housing 10. Confirm the saturation pressure of the methanol through pressure gauge three 19 to determine the temperature of the methanol. The staff adjusts the low-pressure steam inlet volume according to the value displayed on pressure gauge three 19. After heating, the methanol heats and vaporizes the liquid-phase propylene in the first heat exchanger 2. The vaporized propylene gas enters pipeline two 4 and sequentially passes through thermometer two 41, pressure gauge two 42, check valve four 43, and gate valve eight 44 and then is sent to the second branch pipeline 6. The propylene gas entering the second branch pipeline 6 enters the gas-phase propylene unit 62 through gate valve two 61 for supply and use;

[0032] The fourth embodiment of the present invention: When the liquid-phase propylene level in the system is high and needs to be discharged during the normal operation of the propylene refrigeration compressor, close gate valve nine 22, gate valve seven 15, and gate valve one 51. The liquid-phase propylene enters pipeline one 3 from the propylene refrigeration compressor 1. The liquid-phase propylene in pipeline one 3 sequentially passes through gate valve five 31, check valve three 32, pressure gauge one 33, thermometer one 34, and gate valve six 35 and then enters the first heat exchanger 2. At the same time, the low-pressure steam enters the second heat exchanger 7 from the steam inlet pipeline sequentially through gate valve three 81 and check valve one 82. Methanol enters the methanol pipeline 11 from the outside and then sequentially passes through gate valve four 12 and check valve two 13 and enters the housing 10. The low-pressure steam enters the second heat exchanger 7 to indirectly heat the methanol in the housing 10. Confirm the saturation pressure of the methanol through pressure gauge three 19 to determine the temperature of the methanol. The staff adjusts the low-pressure steam inlet volume according to the value displayed on pressure gauge three 19. After heating, the methanol heats the liquid-phase propylene in the first heat exchanger 2 to above zero. The heated liquid-phase propylene enters pipeline two 4 and sequentially passes through thermometer two 41, pressure gauge two 42, check valve four 43, and gate valve eight 44 and then is sent to the first branch pipeline 5. The liquid-phase propylene entering the first branch pipeline 5 enters the liquid-phase propylene unit 52 through gate valve one 51 for recovery or supply to users;

[0033] The fifth embodiment of the present invention: When the propylene refrigeration compressor experiences an unplanned shutdown, the propylene refrigeration compressor enters the maintenance state and shuts down. The pressure within the system is balanced, and the temperature within the system pipelines rises above zero. Therefore, at this time, the propylene can be directly recovered. Close gate valve six 35, gate valve eight 44, and gate valve two 61. The above-zero liquid-phase propylene enters pipeline one 3 from the propylene refrigeration compressor. The liquid-phase propylene passes through gate valve five 31, check valve three 32, pressure gauge one 33, and thermometer one 34 in sequence within pipeline one 3 and then enters pipeline three 14. The liquid-phase propylene then enters pipeline two 4 through gate valve seven 15 and enters the liquid-phase propylene unit 52 through gate valve one 51 for recovery.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A liquid-phase propylene recovery device, comprising: A propylene refrigeration compressor (1), which is used to provide propylene refrigerants at different temperature levels; Characterized in that: a first heat exchanger (2), a pipeline one (3) is led out from the propylene refrigeration compressor (1) to the first heat exchanger (2), and a pipeline two (4) is led out from the first heat exchanger (2), the pipeline two (4) leads out a first branch pipeline (5) and a second branch pipeline (6), a gate valve one (51) is installed on the first branch pipeline (5) and is connected to the liquid-phase propylene unit (52), and a gate valve two (61) is installed on the second branch pipeline (6) and is connected to the gas-phase propylene unit (62); A second heat exchanger (7), the second heat exchanger (7) is connected to a steam inlet pipeline (8) and a steam outlet pipeline (9) that are communicated, a gate valve three (81) and a check valve one (82) are installed along the steam inlet pipeline (8); A housing (10), the first heat exchanger (2) and the second heat exchanger (7) are installed in the housing (10), and a methanol pipeline (11) is connected to the housing (10), a gate valve four (12) and a check valve two (13) are installed in sequence along the methanol pipeline (11); Pipeline one (3), a gate valve five (31), a check valve three (32), a pressure gauge one (33), a thermometer one (34) and a gate valve six (35) are installed in sequence along the pipeline one (3), and a pipeline three (14) is led out between the thermometer one (34) and the gate valve six (35) to the pipeline two (4), a gate valve seven (15) is installed on the pipeline three (14), and a liquid-phase propylene pipeline (21) is led out between the propylene refrigeration compressor (1) and the gate valve five (31), and a gate valve nine (22) is installed on the liquid-phase propylene pipeline (21); Pipeline two (4), a thermometer two (41), a pressure gauge two (42), a check valve four (43) and a gate valve eight (44) are installed along the pipeline two (4); A flare (16), a pipeline four (17) is led out from the pipeline two (4) to the flare (16).

2. The liquid-phase propylene recovery device according to claim 1, characterized in that: A pipeline five (18) is led out from the housing (10) to the flare (16).

3. The liquid-phase propylene recovery device according to claim 2, wherein: A pressure gauge three (19) and a remote transmission liquid level gauge (20) are installed on the housing (10).

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