Natural gas pressure energy recovery device

Abstract

The utility model relates to the technical field of natural gas transportation, and discloses a natural gas pressure energy recovery device which comprises a pressure energy recovery unit, a pressure regulating device and an emergency shut-off valve, and the pressure energy recovery unit and the pressure regulating device are respectively communicated with the emergency shut-off valve. The problem that in the prior art, pressure energy is not recycled in the throttling or pressure reducing process is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas transportation and natural gas dehydration, in particular to a natural gas pressure energy recovery device. Background Art

[0002] In traditional natural gas development, many raw natural gas is pressurized through gas gathering and compressors and then adiabatically expanded using a JT valve to reduce the temperature of the natural gas and remove water and heavy hydrocarbons from the natural gas so that the natural gas meets the downstream hydrocarbon dew point and water dew point requirements.

[0003] However, in the prior art, the process using the JT valve or the pressure regulating valve only meets the needs of the process, and the pressure energy is not recovered during the throttling or pressure reduction process. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the utility model provides a natural gas pressure energy recovery device to solve the problem that the pressure energy is not recovered during the throttling or pressure reduction process in the prior art.

[0005] The technical solution adopted by the utility model to solve the above problems is:

[0006] A natural gas pressure energy recovery device comprises a pressure energy recovery unit, a pressure regulating device and a first emergency shut-off valve. The pressure energy recovery unit and the pressure regulating device are respectively connected to the first emergency shut-off valve.

[0007] As a preferred technical solution, a filter is provided on the connecting pipeline between the first emergency shut-off valve and the inlet of the pressure energy recovery unit.

[0008] As a preferred technical solution, a regulating valve is provided on the connecting pipeline between the first emergency shut-off valve and the inlet of the pressure energy recovery unit.

[0009] As a preferred technical solution, a shut-off valve is provided on the connecting pipeline between the first emergency shut-off valve and the inlet of the pressure energy recovery unit.

[0010] As a preferred technical solution, an inlet pressure temperature detection device is provided on the connecting pipeline between the first emergency shut-off valve and the inlet of the pressure energy recovery unit.

[0011] As a preferred technical solution, it also includes an air-water heat exchanger connected to the outlet of the pressure energy recovery unit.

[0012] As a preferred technical solution, an outlet pressure temperature detection device is provided on the connecting pipeline between the outlet of the pressure energy recovery unit and the air-water heat exchanger.

[0013] As a preferred technical solution, it also includes a check valve connected to the air-water heat exchanger.

[0014] As a preferred technical solution, it also includes a second emergency shut-off valve connected to the air-water heat exchanger.

[0015] As a preferred technical solution, it also includes a BDV valve connected to the air-water heat exchanger.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] (1) When the pressure energy recovery unit of the utility model is operated under normal working conditions, if the pressure energy recovery device is connected in parallel with the JT valve, the outlet temperature after the device is lower than the temperature when the JT valve is in operation. The pressure energy in the natural gas is converted into kinetic energy and then converted into electrical energy through the generator, which can be transported to the nearest substation. At the same time, it can achieve the same function as the JT valve and maintain a stable pressure downstream.

[0018] (2) When the pressure energy recovery device of the utility model is connected in parallel with the pressure regulating valve, the pressure energy recovery unit can adapt to the pressure fluctuation of the upstream or downstream, and adjust the amount of natural gas entering the unit by detecting the pressure change of the upstream or downstream, so as to achieve the effect of stabilizing the upstream or downstream pressure, and at the same time recover the pressure energy of the natural gas and convert it into electrical energy for use by the plant;

[0019] (3) The pressure energy recovery unit of the utility model is skid-mounted and supplied as a complete set with the JT valve or the pressure regulating valve, which simplifies the process layout in the station, reduces the floor space, and saves land resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the utility model;

[0021] Figure 2 for Figure 1 One of the partial enlarged pictures;

[0022] Figure 3 for Figure 1 The second partial enlarged image.

[0023] Marks and their corresponding names in the accompanying drawings: 1. Pressure energy recovery unit, 2. Filter, 3. Regulating valve, 4. Shut-off valve, 5. Check valve, 6. Second emergency shut-off valve, 7. Pressure regulating device, 8. First emergency shut-off valve, 9. UCP control system, 10. Inlet pressure and temperature detection device, 11. Outlet pressure and temperature detection device, 12. BDV valve, 13. Air-water heat exchanger. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0025] Example 1

[0026] like Figures 1 to 3 As shown, Figure 1 As shown, the natural gas pressure energy recovery skid includes an expander + generator set (pressure energy recovery unit 1), a filter 2, a regulating valve 3, a shutoff valve 4, a check valve 5, a second emergency shutoff valve 6, a pressure regulating device 7, a first emergency shutoff valve 8, a UCP control system 9, an inlet pressure and temperature detection device 10, an outlet pressure and temperature detection device 11, a BDV valve 12, an air-water heat exchanger 13 and other supporting valves, instruments, pipelines, etc.

[0027] The pressure energy recovery unit 1 and the pressure regulating device 7 are arranged in parallel. The pressure energy recovery unit 1 operates under normal working conditions. If the pressure energy recovery unit 1 unexpectedly stops or is under maintenance, it switches to the pressure regulating device 7 for operation. Regardless of whether the system is operated by the pressure energy recovery unit 1 or the pressure regulating device 7 (JT valve or pressure regulating valve), the normal operation of the system can be guaranteed to provide stable low-pressure gas for the downstream.

[0028] A first emergency shut-off valve 8 is provided on the main pipe in front of the pressure energy recovery unit 1 and the pressure regulating device 7. When a fire or other unexpected situation occurs in the station, the first emergency shut-off valve 8 can be shut off in an emergency to ensure the safety in the station.

[0029] A filter 2 is provided before the pressure energy recovery unit 1 to ensure the cleanliness of the natural gas entering the unit and protect the safety of the impeller of the expansion unit;

[0030] In some cases, to ensure the stability of the upstream working pressure of the pressure energy recovery unit 1, the unit receives the inlet pressure and temperature signal (through the inlet pressure and temperature detection device 10), and adjusts the amount of natural gas entering the unit through the action of the regulating valve 3; in some cases, to ensure the stability of the downstream working pressure of the pressure energy recovery unit 1, the unit receives the outlet pressure and temperature signal (through the outlet pressure and temperature detection device 11), and adjusts the amount of natural gas entering the unit through the action of the regulating valve 3;

[0031] An SDV valve (blocking valve 4) is provided before the pressure energy recovery unit 1. When an accident occurs during the operation of the unit, the blocking valve 4 can be quickly closed to cut off the natural gas entering the unit.

[0032] An inlet pressure and temperature detection device 10 is provided before the pressure energy recovery unit 1, and an outlet pressure and temperature detection device 11 is provided after the pressure energy recovery unit 1. The pressure and temperature values ​​are transmitted to the pressure energy recovery unit 1, and the generator set adjusts the working state of the unit by comparing with the set value;

[0033] A second emergency shut-off valve 6 is provided after the pressure energy recovery unit 1, the purpose of which is to quickly cut off the connection between the unit and the downstream when an accident occurs to the unit, so as to ensure the safety of the unit;

[0034] A check valve 5 is provided behind the pressure energy recovery unit 1 to prevent the low-pressure pipeline gas on the rear side from returning to the pressure energy recovery skid (pressure energy recovery unit 1) when the pressure energy recovery unit 1 is shut down or started, thereby causing the unit to reverse;

[0035] The pressure energy recovery skid is equipped with a UCP control system 9, which can receive commands such as ESD, start-up permission, and normal shutdown from the superior, and upload the fault alarm, operating status, and emergency stop status of the expansion power generation skid to the superior control system through RS485, and automatically adjust the operating conditions of the pressure energy recovery unit 1 according to the upstream and downstream pressure conditions. It realizes intelligent adjustment and control of the process flow and has self-safety protection function.

[0036] In plants with cooling water systems, an air-water heat exchanger 13 can be installed to exchange heat between the low-temperature and low-pressure gas of the pressure energy recovery unit and the cooling water system, and the cold energy of the low-temperature and low-pressure gas is recovered to the cooling water system, thereby reducing the energy consumption of the cooling water system.

[0037] A BDV valve 12 may or may not be provided downstream of the pressure energy recovery unit 1 according to the overall process requirements of the plant to ensure that there is no overpressure when the pressure energy recovery unit 1 is shut down in an emergency.

[0038] The pressure energy recovery unit is integrated with various valves such as JT, dry gas sealing system, lubricating oil and cooling system and intelligent control system, and compactly arranged into a device skid to reduce the site area. The integrated device skid is installed in the factory, which reduces the workload of on-site installation, solves the difficulties of on-site construction and reduces installation costs.

[0039] After adopting the utility model, not only the needs of the process are met, but also the pressure energy is additionally recovered. The recovered energy is directly consumed in the plant in the form of electric energy, thus reducing the external electric energy of the plant.

[0040] The utility model is suitable for all occasions where JT valves are used to dehydrate and remove heavy hydrocarbons; and is suitable for all distribution stations, gate stations, direct supply users, gas compressor stations, gas power stations and other plants and stations equipped with pressure regulating valves.

[0041] The application of this new process not only achieves the purpose of removing water and heavy hydrocarbons from natural gas, but also recovers additional electrical energy, while reducing the compressor outlet pressure and the energy consumption of the compressor, and has a good application prospect in energy saving.

[0042] Distribution stations, city gate stations, large direct supply users, fuel gas systems of fuel-driven compressors, fuel gas systems of gas-fired generator sets, etc. in gas pipeline projects can all use pressure energy recovery units installed in parallel with pressure regulating valves to recover the pressure energy of natural gas while reducing the pressure and convert it into electrical energy for use by plants and stations.

[0043] Compared with the prior art, the utility model has the following positive effects:

[0044] Under normal working conditions, the pressure energy recovery unit is running. If this pressure energy recovery device is set in parallel with the JT valve, the outlet temperature after this device is lower than the temperature when the JT valve is running. The pressure energy in the natural gas is converted into kinetic energy and then converted into electrical energy through the generator, which can be transported to the nearest substation. At the same time, it can achieve the same function as the JT valve and maintain stable pressure downstream. When this pressure energy recovery device is set in parallel with the pressure regulating valve, the pressure energy recovery unit can adapt to the pressure fluctuations upstream or downstream, and adjust the amount of natural gas entering the unit by detecting the upstream or downstream pressure changes, so as to achieve the effect of stabilizing the upstream or downstream pressure, and at the same time recover the pressure energy of the natural gas and convert it into electrical energy for use by the plant.

[0045] In plants with cooling water systems, an air-water heat exchanger can be installed. The low-temperature, low-pressure gas from the pressure energy recovery unit can exchange heat with the cooling water system. The cold energy of the low-temperature, low-pressure gas can be recovered and enter the cooling water system, reducing the energy consumption of the cooling water system.

[0046] The pressure energy recovery unit is integrated with various valves, auxiliary systems and intelligent control systems to realize intelligent regulation and control of the process flow. Through the intelligent control system with independent intellectual property rights, it realizes digital management functions such as real-time data collection, analysis, and uploading, conducts real-time monitoring and daily management of the production situation of the device, accepts instructions from superiors, realizes remote control, and has self-safety protection functions.

[0047] The pressure energy recovery unit and JT valve or pressure regulating valve are supplied as a skid-mounted set, which simplifies the process layout within the station, reduces the floor space and saves land resources.

[0048] As described above, the utility model can be implemented well.

[0049] The above is only a preferred embodiment of the utility model and does not limit the utility model in any form. According to the technical essence of the utility model, within the spirit and principles of the utility model, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the utility model.

Claims

1. A natural gas pressure energy recovery device, characterized in that: It comprises a pressure energy recovery unit (1), a pressure regulating device (7), and a first emergency shut-off valve (8), wherein the pressure energy recovery unit (1) and the pressure regulating device (7) are respectively connected to the first emergency shut-off valve (8); An inlet pressure and temperature detection device (10) is provided on the connecting pipeline between the first emergency shut-off valve (8) and the inlet of the pressure energy recovery unit (1); It also includes a gas-water heat exchanger (13) connected to the outlet of the pressure energy recovery unit (1); An outlet pressure temperature detection device (11) is provided on the connecting pipeline between the outlet of the pressure energy recovery unit (1) and the gas-water heat exchanger (13).

2. A natural gas pressure energy recovery device according to claim 1, characterized in that: A filter (2) is provided on the connecting pipeline between the first emergency shut-off valve (8) and the inlet of the pressure energy recovery unit (1).

3. A natural gas pressure energy recovery device according to claim 1, characterized in that: A regulating valve (3) is provided on the connecting pipeline between the first emergency shut-off valve (8) and the inlet of the pressure energy recovery unit (1).

4. A natural gas pressure energy recovery device according to claim 1, characterized in that: A cut-off valve (4) is provided on the connecting pipeline between the first emergency shut-off valve (8) and the inlet of the pressure energy recovery unit (1).

5. A natural gas pressure energy recovery device according to claim 1, characterized in that: It also includes a check valve (5) connected to the air-water heat exchanger (13).

6. A natural gas pressure energy recovery device according to claim 1, characterized in that: It also includes a second emergency shut-off valve (6) in communication with the air-water heat exchanger (13).

7. A natural gas pressure energy recovery device according to claim 1, characterized in that: It also includes a BDV valve (12) in communication with the air-water heat exchanger (13).

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