Ethylene device cold box closed discharge system

Abstract

The utility model discloses an ethylene unit cold box sealed discharge system, which comprises a cold box, a fan and a torch, the top of the cold box is provided with an exhaust port, the exhaust port is connected with an inlet of the fan, and an outlet of the fan is connected with the torch. According to the utility model, the top of the cold box is connected to the inlet of the fan in an air discharge manner, the combustible gas which is leaked into the box body of the cold box due to the damage of the heat exchanger in the cold box is discharged to the torch through the fan, and the pressure is balanced by nitrogen charging, so that the closed discharge of the combustible gas in the box body of the cold box is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of ethylene devices, in particular to a closed discharge system of a cold box of an ethylene device. Background Art

[0002] The cold box of the ethylene unit is a set of high-efficiency, heat-insulating and cold-preserving low-temperature heat exchange equipment. The cold box contains multiple heat exchangers and separators, and multiple streams of materials are heat-exchanged simultaneously. The heat exchangers and separators are packed in a box-shaped object with insulating materials, and nitrogen is added to ensure a slight positive pressure in the box to prevent air from entering. There is a nitrogen filling pipeline at the bottom of the cold box and a discharge port at the top, which will discharge the used nitrogen on-site into the atmosphere. If a heat exchanger in the cold box is damaged, causing combustible gas to leak into the box, it will be discharged to the site along with the nitrogen. Then, due to the discharge of combustible gas in the box to the site, there may be risks of fire and explosion, which will pose a hidden danger to the working environment of the device. Utility Model Content

[0003] In order to solve the problems of the prior art, the utility model provides a closed discharge system for a cold box of an ethylene device.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] A closed discharge system for a cold box of an ethylene device comprises a cold box, a fan and a flare. An exhaust port is arranged on the top of the cold box, the exhaust port is connected to the inlet of the fan, and the outlet of the fan is connected to the flare. The cold box is connected to a nitrogen filling pipeline to fill nitrogen into the cold box.

[0006] Furthermore, the pipeline between the cold box and the flare is a flare discharge pipeline, and a fan is provided on the flare discharge pipeline, and the exhaust gas is pressurized by the fan and sent to the flare to achieve fully enclosed discharge.

[0007] Furthermore, an oxygen content detector is provided between the fan and the flare to monitor the oxygen content in the flare of the gas leaking from the cooling box.

[0008] Furthermore, a pressure gauge is provided between the fan and the torch, and the pressure gauge is used to monitor the back pressure of the torch, so that the operator can adjust the fan frequency. The pressure gauge is located between the oxygen content detector and the torch.

[0009] Furthermore, pressure gauges are provided at the bottom and top of the cold box respectively. The pressure gauge at the bottom is used to measure the pressure of the gas at the bottom of the cold box body, and the pressure gauge at the top is used to measure the pressure of the gas at the top of the cold box body.

[0010] Furthermore, a pressure gauge is provided between the cold box and the fan to monitor the cold box shell pressure.

[0011] Furthermore, a flow meter is provided between the cold box and the fan to monitor changes in leakage flow, and the flow meter is close to the fan.

[0012] Furthermore, a pressure balancing pipeline is provided between the bottom and the top of the cold box.

[0013] Furthermore, there are two fans, which are arranged in parallel and serve as backup for each other.

[0014] Furthermore, the torch is a low-pressure torch, or two torches, a low-pressure torch and a high-pressure torch.

[0015] Furthermore, a regulating valve is provided between the fan and the high-pressure flare to adjust the discharge of the cold box. When the discharge of the low-pressure flare has reached the maximum and the shell pressure of the cold box is still very high, the regulating valve is opened to discharge part of the leaked gas to the high-pressure flare to reduce the shell pressure. The regulating valve is interlocked to prevent the high-pressure flare pressure from causing gas phase backflow.

[0016] Furthermore, the discharge port on the top of the cold box is connected to an atmospheric discharge pipeline, and a valve is provided on the atmospheric discharge pipeline.

[0017] Furthermore, there are two atmospheric discharge pipelines, one of which is provided with a solenoid valve, and the other is provided with a hand valve. The solenoid valve is an interlocking solenoid valve. When the fan stops operating or the pressure of the cold box is high, the solenoid valve opens to release the pressure to the atmosphere to avoid damage to the cold box due to excessive pressure. When the solenoid valve fails to open or the fan needs to be switched, the pressure can be adjusted by exhausting the air with the hand valve. The solenoid valve is a fully open or fully closed valve that can only be used for emergency treatment, while the hand valve can play a certain role in regulation to ensure the stability of the cold box pressure.

[0018] Furthermore, the atmospheric discharge pipeline is connected to a dilution nitrogen pipeline. When discharging the atmosphere, the dilution nitrogen pipeline is opened to dilute the combustible gas discharged into the atmosphere with nitrogen to reduce the concentration of the combustible gas.

[0019] Furthermore, the top and bottom of the cold box are connected to nitrogen filling pipelines. Since the cold box is severely agglomerated and the pressure difference between the upper and lower parts of the box is large, a nitrogen filling pipeline is added on the top of the cold box to balance the pressure of the cold box.

[0020] Furthermore, a valve is provided on the nitrogen filling pipeline.

[0021] Furthermore, a flow meter is provided on the nitrogen filling pipeline.

[0022] Beneficial effects of the utility model:

[0023] The utility model connects the air discharge at the top of the cold box to the inlet of the fan, and discharges the combustible gas leaking into the cold box body due to damage of the heat exchanger inside the cold box to the torch through the fan, and balances the pressure by nitrogen filling, thereby realizing the closed discharge of the combustible gas in the cold box body.

[0024] After the utility model changes the gas phase emission of the cold box body into a closed emission torch, the on-site combustible gas content meets the standard, the potential safety hazard of on-site operation is eliminated, and the safe and long-term operation of the device is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a cold box sealing and discharging system of an ethylene device according to the utility model.

[0026] In the figure: 1. cold box, 2. fan I, 3. fan II, 4. low-pressure torch, 5. high-pressure torch, 6. oxygen content detector, 7. pressure gauge I, 8. pressure gauge II, 9. flow meter I, 10. pressure gauge III, 11. pressure gauge IV, 12. pressure gauge V, 13. solenoid valve, 14. manual valve I, 15. flow meter II, 16. manual valve II, 17. torch discharge pipeline, 18. atmospheric discharge pipeline I, 19. atmospheric discharge pipeline II, 20. nitrogen filling pipeline, 21. pressure balance pipe. DETAILED DESCRIPTION

[0027] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0028] Example 1

[0029] like Figure 1As shown, a sealed discharge system of a cold box of an ethylene device comprises a cold box 1, a fan, and a flare. An exhaust port is provided on the top of the cold box 1, the exhaust port is connected to the inlet of the fan, and the outlet of the fan is connected to the flare. The cold box 1 is connected to a nitrogen filling pipeline 20, and nitrogen is filled into the cold box 1. The pipeline between the cold box 1 and the flare is a flare discharge pipeline 17, and a fan is provided on the flare discharge pipeline 17. An oxygen content detector 6 is provided between the fan and the flare. There are two fans, namely fan I2 and fan II3, which are arranged in parallel and standby for each other. There are two flares, namely a low-pressure flare 4 and a high-pressure flare 5. A pressure gauge IV11 is provided between the oxygen content detector 6 and the low-pressure flare 4, a pressure gauge V12 is provided between the oxygen content detector 6 and the high-pressure flare 5, and a regulating valve is provided between the oxygen content detector 6 and the high-pressure flare 5. A pressure gauge I7 is provided at the bottom of the cold box 1, and a pressure gauge II8 is provided at the top. A pressure gauge III10 and a flow meter I9 are provided between the cold box 1 and the fan, the flow meter I9 is ​​close to the fan, and the pressure gauge III10 is close to the cold box 1. The discharge port at the top of the cold box 1 is connected to the atmospheric discharge pipeline, and a valve is provided on the atmospheric discharge pipeline. There are two atmospheric discharge pipelines, namely, the atmospheric discharge pipeline I18 and the atmospheric discharge pipeline II19. The atmospheric discharge pipeline I18 is provided with a solenoid valve 13, and the atmospheric discharge pipeline II19 is provided with a hand valve I14. A pressure balance pipeline 21 is provided between the bottom and the top of the cold box 1. The atmospheric discharge pipeline I18 is connected to the diluted nitrogen pipeline 20. The top and bottom of the cold box 1 are connected to the nitrogen filling pipeline 20, and nitrogen is filled into the cold box 1. The nitrogen filling pipeline 20 is provided with a flow meter II15 and a hand valve 16, and the flow meter II15 is close to the cold box 1.

[0030] The nitrogen at the bottom of cold box 1 enters cold box 1 through hand valve Ⅱ16, and the nitrogen at the top of cold box 1 enters cold box 1 through hand valve Ⅱ16. The flow rate is adjusted by flow meter Ⅱ15. The nitrogen brings the combustible gas leaked from the bottom of cold box 1 to the top of cold box 1, passes through the pipeline through flow meter Ⅰ9 and pressure gauge Ⅲ10, enters the fan, and is discharged to low-pressure torch 4 and high-pressure torch 5 through the fan. The oxygen analyzer 6 is used to monitor the oxygen content in the exhaust gas, and the pressure gauge Ⅱ8 is used to monitor the shell pressure of cold box 1. Through the two upper and lower nitrogen filling lines of cold box 1, the total amount of nitrogen supplement is guaranteed to be 12-17Nm 3 . The bottom pressure of the cold box 1 is controlled at 1.0 KPa by adjusting the frequency of the fan and the opening of the regulating valve of the high-pressure torch 5. When the pressure of the cold box 1 is too high or the fan suddenly trips, the solenoid valve 13 automatically opens to release the pressure to ensure the stability of the shell pressure of the cold box 1. When the solenoid valve 13 fails to open or the fan needs to be switched, the pressure can be adjusted by the exhaust manual valve Ⅰ14 to ensure the stability of the pressure of the cold box 1. When discharging to the atmosphere, the dilution nitrogen pipeline is opened to dilute the combustible gas discharged to the atmosphere with nitrogen to reduce the concentration of the combustible gas.

Claims

1. A closed discharge system for cold box of ethylene plant, characterized in that: The utility model comprises a cold box, a fan and a torch. The top of the cold box is provided with an exhaust port, the exhaust port is connected with the inlet of the fan, the outlet of the fan is connected with the torch; the cold box is connected with a nitrogen filling pipeline.

2. The ethylene plant cold box closed discharge system according to claim 1, characterized in that: The pipeline between the cold box and the flare is a flare discharge pipeline, and a fan is arranged on the flare discharge pipeline.

3. The closed discharge system of the cold box of the ethylene plant according to claim 1, characterized in that: An oxygen content detector is arranged between the fan and the torch.

4. The ethylene plant cold box closed discharge system according to claim 1, characterized in that: A pressure gauge is provided between the fan and the torch, pressure gauges are provided at the bottom and the top of the cold box respectively, and a pressure gauge is provided between the cold box and the fan.

5. The ethylene plant cold box closed discharge system according to claim 1, characterized in that: A flow meter is provided between the cold box and the fan, and the flow meter is close to the fan.

6. The ethylene plant cold box closed discharge system according to claim 1, characterized in that: There are two fans; or there are two torches, a low-pressure torch and a high-pressure torch, respectively, and a regulating valve is provided between the fan and the high-pressure torch.

7. The closed discharge system for cold box of ethylene plant according to claim 1, characterized in that: A pressure balancing pipeline is provided between the bottom and the top of the cold box.

8. The closed discharge system for cold box of ethylene plant according to claim 1, characterized in that: The top and bottom of the cold box are connected to a nitrogen filling pipeline, and a valve and a flow meter are arranged on the nitrogen filling pipeline.

9. The closed discharge system for cold box of ethylene plant according to claim 1, characterized in that: The discharge port at the top of the cold box is connected to an atmospheric discharge pipeline, and a valve is arranged on the atmospheric discharge pipeline.

10. The ethylene plant cold box closed discharge system according to claim 9, characterized in that: There are two atmospheric discharge pipelines, one of which is provided with a solenoid valve, and the other is provided with a hand valve.

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