An apparatus for utilizing natural gas pressure energy and cold energy

Abstract

The application provides a device utilizing natural gas pressure energy and cold energy. The device is connected with an upstream pipe for natural gas, and comprises a differential pressure generator set, a heat exchange unit and an expander bypass pressure stabilizing unit. The differential pressure generator set is connected with the heat exchange unit in series, and then connected with the expander bypass pressure stabilizing unit in parallel. The device is connected with a downstream natural gas equipment after being integrated. The expander bypass pressure stabilizing unit comprises a first pressure stabilizing and regulating unit, a second pressure stabilizing and regulating unit and a third pressure stabilizing and regulating unit. The first pressure stabilizing and regulating unit, the second pressure stabilizing and regulating unit and the third pressure stabilizing and regulating unit are connected in parallel. Under the premise of ensuring normal and smooth use of the downstream natural gas equipment, the device can comprehensively utilize the abundant energy of the natural gas through the ingenious combination and the advanced control method. The device can meet the working requirements under the harsh working conditions of the upstream natural gas with large flow and large pressure difference fluctuation.

Description

Technical Field

[0001] This invention relates to the field of integrated energy recovery technology of natural gas, specifically to a device that utilizes the pressure energy and cold energy of natural gas. Background Technology

[0002] While natural gas pressure regulating station technology is becoming increasingly mature internationally, there is still significant room for improvement in areas such as energy conservation and environmental protection, the application of intelligent control technology, and reliability enhancement. Due to the diverse components of the extracted gas source, and the varying volume percentages of each gas within these components, coupled with numerous overhead sections in long-distance natural gas pipelines, the combined effects of diurnal temperature variations and seasonal factors cause thermal expansion and contraction of the gas within the pipelines, resulting in pressure fluctuations. Furthermore, upstream and midstream gate stations dynamically adjust their gas distribution plans based on seasonal changes and actual user demands. These factors, combined with peak and off-peak gas consumption by residential and commercial users, directly lead to significant fluctuations in the natural gas received by downstream gas-fired power plants within a short period, making precise regulation difficult and failing to meet the requirements for stable downstream production. Typically, upstream gate stations supply natural gas using high-flow, high-pressure dedicated pipelines, while the actual gas pressure required by downstream gas turbines or other gas-consuming equipment is generally lower. This objectively provides the prerequisites for high flow rates and high pressure differentials. The abundant energy inherent in this pressure regulating process is wasted due to inefficient utilization, which is a significant loss.

[0003] For a long time, key supporting equipment and core technology control methods for pressure regulating stations in gas-fired power plants have been subject to foreign monopolies and technological blockades. In particular, there are no mature precedents to draw upon for the combined recovery and application of natural gas pressure energy and cold energy, or for the continuous and stable gas supply technology from gas turbines. There is a lack of experience in the comprehensive recovery and application of natural gas pressure energy and cold energy. Compared with existing solutions, most only select one characteristic for recovery and utilization, which leads to insufficient recovery and utilization of surplus energy from natural gas. When upstream pipeline natural gas flows at high flow rates (40,500–145,000 Nm³), this becomes particularly problematic. 3 Under operating conditions with fluctuating parameters such as pressure difference (5-9 MPa) and pressure differential ( / h), it is extremely difficult and challenging to not only ensure stable, accurate, and reliable gas delivery to downstream equipment, but also to achieve joint recovery of the pressure energy and cold energy of natural gas. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide a device that utilizes natural gas pressure energy and cold energy with high energy utilization rate and high power generation efficiency.

[0005] To solve the above problems, the technical solution of the present invention is as follows:

[0006] A device utilizing the pressure energy and cold energy of natural gas is disclosed. The inlet of the device is connected to an upstream pipeline natural gas supply. The device includes a differential pressure generator set, a heat exchange unit, and an expander bypass pressure stabilizing unit. The differential pressure generator set is connected in series with the heat exchange unit and then in parallel with the expander bypass pressure stabilizing unit. The combined units are then connected to downstream natural gas-consuming equipment. The expander bypass pressure stabilizing unit includes a first pressure stabilizing and regulating unit, a second pressure stabilizing and regulating unit, and a third pressure stabilizing and regulating unit, which are connected in parallel.

[0007] Preferably, the differential pressure generator set includes a pneumatic isolation valve, a filter, a pressure sensor, a temperature sensor, an electric butterfly valve, a planar turbine expander, a generator and grid connection cabinet, and a check valve. The pneumatic isolation valve, filter, pressure sensor, temperature sensor, and electric butterfly valve are sequentially connected to the natural gas inlet of the planar turbine expander. The generator and grid connection cabinet are directly connected to the output shaft of the planar turbine expander to obtain sufficient torque required for power generation. The natural gas outlet of the planar turbine expander is sequentially connected to the pressure sensor, temperature sensor, pneumatic isolation valve, and check valve.

[0008] Preferably, the filter is a cone-shaped filter used for coarse filtration to prevent large particles of impurities from damaging the equipment.

[0009] Preferably, the heat exchange unit includes a single-tube heat exchanger. The natural gas outlet of the differential pressure generator set is connected to the natural gas inlet of the single-tube heat exchanger through a pressure pipeline element. The air conditioning cooling water inlet is connected to the inlet of the single-tube heat exchanger in sequence through a pressure pipeline element, consisting of a temperature sensor, a pressure sensor, and a valve group. The outlet of the single-tube heat exchanger is connected to the air conditioning chilled water inlet in sequence through a pressure pipeline element, consisting of a temperature sensor, a temperature switch, a flow switch, and a valve group. The natural gas, heated by the heat exchange, is connected in parallel with the expansion compressor bypass pressure stabilizing unit through the outlet of the single-tube heat exchanger and then connected to other downstream gas-consuming equipment.

[0010] Preferably, the first pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve; the second pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve; and the third pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve. Compressed air passes through pressure piping components. The pneumatic actuators, which are respectively supplied to the first, second, and third pressure stabilizing and regulating units, serve as the valve torque input source to control the opening and closing of the pneumatic isolation valve. The monitoring and working pressure regulators and shut-off valves in the first, second, and third pressure stabilizing and regulating units respectively use pressure taps on the natural gas pipeline. After comparing the pressure value set by the spring inside the regulator, the valve opening is automatically adjusted, thereby achieving precise pressure regulation.

[0011] Preferably, the operating pressure ranges of the first voltage regulating unit, the second voltage regulating unit, and the third voltage regulating unit are preset in a gradient ratio from low to high.

[0012] Preferably, the pressure and flow rate of the natural gas inlet and outlet of the device are collected in real time. After specific program logic calculation and judgment by the control system, the optimal control method is quickly selected. By changing the opening and closing state of the pneumatic isolation valves before and after the first, second, and third pressure regulating units, the working path can be quickly and flexibly switched. Depending on the situation, the pressure regulating control method specifically includes:

[0013] When the upstream gas flow is detected to be low but the pressure is relatively low: the valves before and after the differential pressure generator set are closed, and the valves before and after the first pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0014] When the upstream gas flow is detected to be low and the pressure is relatively moderate: the valves before and after the differential pressure generator set are closed, and the valves before and after the second pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0015] When the upstream gas flow is detected to be low but the pressure is relatively high: the valves before and after the differential pressure generator set are closed, and the valves before and after the third pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0016] When the upstream gas flow is moderate but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are opened, and the front and rear valves of all pressure regulating units in the expander bypass pressure regulating unit are closed;

[0017] When the upstream gas flow rate is moderate and the pressure is relatively moderate: the valves before and after the differential pressure generator set are both open, and the valves before and after the first pressure regulating unit are both open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed.

[0018] When the upstream gas flow is moderate but the pressure is relatively high: the valves before and after the differential pressure generator set are both open, and the valves before and after the second pressure regulating unit are both open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed.

[0019] When a large volume of gas is detected from upstream but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are opened, and in the expander bypass pressure regulating unit, except for the front and rear valves of the first pressure regulating unit which are both open, the front and rear valves of the other pressure regulating units are closed.

[0020] When a large amount of gas is detected from upstream and the pressure is relatively moderate: the valves before and after the differential pressure generator set are both opened, and the valves before and after the second pressure regulating unit are both opened, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed.

[0021] When a large volume of gas is detected from upstream, but the pressure is relatively high: both the front and rear valves of the differential pressure generator set are opened, and in the expander bypass pressure regulating unit, except for the front and rear valves of the third pressure regulating unit which are both open, the front and rear valves of the other pressure regulating units are closed.

[0022] When the first voltage regulator unit fails and automatically shuts off, the control system will automatically activate the second voltage regulator unit to operate.

[0023] When the second voltage regulator unit fails and automatically shuts off, the control system will automatically activate the third voltage regulator unit to operate.

[0024] When the third voltage regulator unit fails and automatically shuts off, the control system will automatically activate the first voltage regulator unit and the second voltage regulator unit, which will work simultaneously in parallel.

[0025] Compared with existing technologies, the device of this invention, while ensuring the normal and stable gas consumption of downstream gas-using equipment, comprehensively utilizes a clever combination of methods and advanced control techniques to fully recover and utilize the abundant pressure and cold energy contained in the natural gas during the process of gas-fired power plant pressure regulating station. By transmitting electricity to the grid through generators and grid-connected cabinets, the cost of electricity delivered to the plant is further reduced, benefiting society and improving economic efficiency. This device features high energy utilization and high power generation efficiency, improving energy efficiency while also saving energy and protecting the environment, thus saving unnecessary energy expenditure costs. Given the large fluctuations in the flow and pressure range of upstream gas, and considering that differential pressure generator sets cannot achieve controllable pressure regulation, this invention also adds an expander bypass pressure stabilizing unit, which can meet the needs of operating under harsh conditions of large flow and large differential pressure fluctuations in upstream gas. It also features a high degree of intelligent control. Attached Figure Description

[0026] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] Specifically, the present invention provides a device that utilizes the pressure energy and cold energy of natural gas, such as... Figure 1 As shown, the inlet of the device is connected to the upstream pipeline natural gas. The device includes a differential pressure generator set and a heat exchange unit connected in series with the differential pressure generator set. The differential pressure generator set and the heat exchange unit are connected in series and then connected in parallel with the expander bypass pressure stabilizing unit. After being combined, they are connected to the downstream gas-using equipment of the natural gas.

[0030] Pressure energy recovery is primarily achieved through the differential pressure generator set, which includes a pneumatic isolation valve 1, a filter 2, a pressure sensor 3, a temperature sensor 4, an electric butterfly valve 5, a planar expander 6, a generator and grid connection cabinet 7, and a check valve 8. The pneumatic isolation valve 1, filter 2, pressure sensor 3, temperature sensor 4, and electric butterfly valve 5 are sequentially connected to the natural gas inlet of the planar expander 6. The filter 2 is a cone-shaped filter used for coarse filtration to prevent large particles from damaging the equipment. The generator and grid connection cabinet 7 are directly connected to the output shaft of the planar expander 6 to obtain sufficient torque for power generation. The natural gas outlet of the planar expander 6 is sequentially connected to the pressure sensor 3, temperature sensor 4, pneumatic isolation valve 1, and check valve 8.

[0031] The cold energy recovery is mainly achieved through the heat exchange unit, which includes a single-tube heat exchanger 9. Utilizing the characteristic that natural gas expands and depressurizes in an expander, its volume increases while its temperature decreases, a pipeline is connected to the natural gas inlet 9A of the single-tube heat exchanger 9. A valve group is connected to the water inlet 9C of the single-tube heat exchanger 9. The valve group uses a redundant parallel connection of electric shut-off valve 12 and manual shut-off valve 13. The electric shut-off valve is preferentially used to achieve precise control of the heat exchange medium based on the expander outlet temperature. If the electric shut-off valve fails, the manual shut-off valve can be used temporarily to adjust the flow rate of the heat exchange medium. Next, a pressure sensor 3 and a temperature sensor 4 are connected sequentially, and finally, they are all connected to the air conditioning cooling water inlet. At the water outlet 9D of the single-tube heat exchanger 9, a temperature sensor 4, a temperature switch 14, and a flow switch 15 are connected sequentially, followed by another valve group. This valve group also uses a parallel connection of electric shut-off valve 12 and manual shut-off valve 13, and is connected to the air conditioning chilled water inlet. Finally, the natural gas, after being heated by heat exchange, is collected at the outlet 9B of the single-tube heat exchanger 9 and the expander bypass pressure stabilizing unit, and then connected to other downstream gas-using equipment. The natural gas vent 9E of the single-tube heat exchanger 9 is sequentially connected to the manual ball valve 10 and the safety valve 11 through pressure pipeline components. When the natural gas pressure inside the equipment reaches the safe release pressure value, the safety valve will be automatically opened, and intermittent discharge will be carried out through the vent pipeline, which can prevent the container from failing or exploding due to overpressure.

[0032] In the device of this invention, the expander bypass pressure stabilizing unit has three different pressure stabilizing and regulating unit branches: a first pressure stabilizing and regulating unit A, a second pressure stabilizing and regulating unit B, and a third pressure stabilizing and regulating unit C, which are arranged in parallel. Each pressure stabilizing and regulating unit branch has a similar equipment configuration: the first pressure stabilizing and regulating unit A is connected in series with a pneumatic isolation valve 1A, a pressure gauge 16A, a monitoring pressure regulator 17A (including a shut-off valve), a working pressure regulator 18A, a pressure gauge 16A, and a pneumatic isolation valve 1A. The second pressure stabilizing and regulating unit B is connected in series with a pneumatic isolation valve 1B, a pressure gauge 16B, a monitoring pressure regulator 17B (including a shut-off valve), a working pressure regulator 18B, a pressure gauge 16B, and a pneumatic isolation valve 1B. The third pressure stabilizing and regulating unit C is connected in series with a pneumatic isolation valve 1C, a pressure gauge 16C, a monitoring pressure regulator 17C (including a shut-off valve), a working pressure regulator 18C, a pressure gauge 16C, and a pneumatic isolation valve 1C. Compressed air is delivered via pressure pipeline components to the pneumatic actuators on pneumatic isolation valves 1A, 1B, and 1C, serving as the torque output source for valve opening and closing. The monitoring regulators 17A, 17B, and 17C (including shut-off valves), and the working regulators 18A, 18B, and 18C, respectively, use pressure taps on the natural gas pipeline. After pressure comparison by the internal springs of the regulators, the valve opening is automatically adjusted, thereby achieving precise pressure regulation.

[0033] Given the inherent mechanical structure of the pressure regulator, once set, it has a fixed operating range. To accommodate large pressure fluctuations, multiple pressure-stabilizing and regulating branches are required. Each branch has different parameter settings and operating ranges. To facilitate intelligent control, the operating ranges are set with preset parameters in a gradient distribution, ensuring each branch has a clearly defined and suitable operating condition range. This guarantees a relatively controllable pressure stabilization accuracy at the outlet. Furthermore, the operating ranges of adjacent regulators must overlap by at least one-quarter, with no gaps in pressure distribution. Each pressure-stabilizing and regulating branch flexibly switches between operating paths via the opening and closing of pneumatic isolation valves. These valves are controlled by an intelligent control system. Automated data acquisition instruments collect real-time pressure, temperature, and flow parameters of the natural gas before and after the differential pressure generator set and upload them to the intelligent control system as parameters for analysis using pre-set algorithms. Based on the final control execution scheme, by changing the opening and closing states of the pneumatic isolation valves before and after each pressure regulating unit branch, several modes can be combined as follows. The specific control process is summarized below:

[0034] 1. When the upstream gas flow is low but the pressure is relatively low: the valves before and after the differential pressure generator set are closed, and the valves before and after the first pressure regulating unit A are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0035] 2. When the upstream gas flow is low and the pressure is relatively moderate: the valves before and after the differential pressure generator set are closed, and the valves before and after the second pressure regulating unit B are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0036] 3. When the upstream gas flow is low but the pressure is relatively high: the valves before and after the differential pressure generator set are closed, and the valves before and after the third pressure regulating unit C are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0037] 4. When the upstream gas flow rate is moderate but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are opened, and the front and rear valves of all pressure regulating units in the expander bypass pressure regulating unit are closed.

[0038] 5. When the upstream gas flow rate is moderate and the pressure is relatively moderate: the valves before and after the differential pressure generator set are both open, and the valves before and after the first pressure regulating unit A are both open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed.

[0039] 6. When the upstream gas flow rate is moderate but the pressure is relatively high: the valves before and after the differential pressure generator set are both open, and the valves before and after the second pressure regulating unit B in the expander bypass pressure regulating unit are both closed.

[0040] 7. When a large amount of gas is detected from upstream but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are open, and in the expander bypass pressure regulating unit, except for the front and rear valves of the first pressure regulating unit A which are open, the front and rear valves of the other pressure regulating units are closed.

[0041] 8. When a large amount of gas is detected from upstream and the pressure is relatively moderate: the valves before and after the differential pressure generator set are opened, and the valves before and after the second pressure regulating unit B in the expander bypass pressure regulating unit are closed, except for the valves before and after the second pressure regulating unit B.

[0042] 9. When a large amount of gas is detected from upstream, but the pressure is relatively high: the valves before and after the differential pressure generator set are opened, and the valves before and after the third pressure regulating unit C are opened, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed.

[0043] 10. When the first voltage regulator unit A fails and automatically shuts off, the control system will automatically activate the second voltage regulator unit B.

[0044] 11. When the second voltage regulator unit B fails and automatically shuts off, the control system will automatically activate the third voltage regulator unit C.

[0045] 12. When the third voltage regulator unit C fails and is automatically disconnected, the control system will automatically activate the first voltage regulator unit A and the second voltage regulator unit B simultaneously, and they will work in parallel.

[0046] It should be added that, in addition to meeting certain voltage regulation gradient requirements, the voltage regulator's capacity for voltage regulation and the feasibility of replacement in case of failure must also be considered when setting parameters. Therefore, the following conditions must also be met in terms of processing capacity:

[0047] (Voltage Regulator Units A and B) > Voltage Regulator Unit C > Voltage Regulator Unit B > Voltage Regulator Unit A.

[0048] In summary, this invention, through a clever combination of methods and advanced control techniques, achieves pressure reduction and stabilization while fully recovering and utilizing the abundant pressure and cold energy contained in the natural gas during the process of gas-fired power plant pressure regulating stations. The device transmits electricity to the grid via a generator and grid-connected cabinet, improving power generation efficiency and further reducing the cost of electricity delivered to the plant, benefiting society. The recovery and utilization of cold energy is characterized by energy conservation, emission reduction, and environmental friendliness. It saves energy consumption while also reducing unnecessary energy expenditure costs, demonstrating a high degree of social responsibility. Given the large fluctuations in the flow and pressure range of upstream gas, traditional energy recovery devices cannot simultaneously meet the needs of stable operation of downstream gas-using equipment. This invention overcomes this deficiency by adding an expander bypass pressure stabilization unit to the system and employing specific control methods to meet the intelligent operating requirements under the harsh conditions of large flow and large pressure differential fluctuations in upstream gas. It is innovative, advanced, practical, and reliable.

[0049] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for utilizing natural gas pressure energy and cold energy, applied to a device utilizing natural gas pressure energy and cold energy, characterized in that, The device's inlet is connected to upstream pipeline natural gas. The device includes a differential pressure generator set, a heat exchange unit, and an expander bypass pressure stabilizing unit. The differential pressure generator set and the heat exchange unit are connected in series, and then connected in parallel with the expander bypass pressure stabilizing unit. The combined units are then connected to downstream natural gas-consuming equipment. The expander bypass pressure stabilizing unit includes a first pressure stabilizing and regulating unit, a second pressure stabilizing and regulating unit, and a third pressure stabilizing and regulating unit, which are connected in parallel. The operating pressure ranges of the first pressure stabilizing and regulating unit, the second pressure stabilizing and regulating unit, and the third pressure stabilizing and regulating unit are preset in a gradient ratio from low to high. The system collects real-time pressure and flow parameters of the natural gas inlet and outlet of the device. After specific program logic calculations and judgments by the control system, it quickly selects the optimal control method. This is achieved by changing the opening and closing states of the pneumatic isolation valves before and after the first, second, and third pressure regulating units, thereby enabling rapid and flexible switching of the working path. Depending on the specific situation, the pressure regulating control methods include: When the upstream gas flow is detected to be low but the pressure is relatively low: the valves before and after the differential pressure generator set are closed, and the valves before and after the first pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed. When the upstream gas flow is detected to be low and the pressure is relatively moderate: the valves before and after the differential pressure generator set are closed, and the valves before and after the second pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed. When the upstream gas flow is detected to be low but the pressure is relatively high: the valves before and after the differential pressure generator set are closed, and the valves before and after the third pressure regulating unit are open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are closed. When the upstream gas flow is moderate but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are opened, and the front and rear valves of all pressure regulating units in the expander bypass pressure regulating unit are closed; When the upstream gas flow rate is moderate and the pressure is relatively moderate: the valves before and after the differential pressure generator set are both open, and the valves before and after the first pressure regulating unit are both open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed. When the upstream gas flow is moderate but the pressure is relatively high: the valves before and after the differential pressure generator set are both open, and the valves before and after the second pressure regulating unit are both open, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed. When a large volume of gas is detected from upstream but the pressure is relatively low: both the front and rear valves of the differential pressure generator set are opened, and in the expander bypass pressure regulating unit, except for the front and rear valves of the first pressure regulating unit which are both open, the front and rear valves of the other pressure regulating units are closed. When a large amount of gas is detected from upstream and the pressure is relatively moderate: the valves before and after the differential pressure generator set are both opened, and the valves before and after the second pressure regulating unit are both opened, while the valves before and after the other pressure regulating units in the expander bypass pressure regulating unit are all closed. When a large volume of gas is detected from upstream, but the pressure is relatively high: both the front and rear valves of the differential pressure generator set are opened, and in the expander bypass pressure regulating unit, except for the front and rear valves of the third pressure regulating unit which are both open, the front and rear valves of the other pressure regulating units are closed. When the first voltage regulator unit fails and automatically shuts off, the control system will automatically activate the second voltage regulator unit to operate. When the second voltage regulator unit fails and automatically shuts off, the control system will automatically activate the third voltage regulator unit to operate. When the third voltage regulator unit fails and automatically shuts off, the control system will automatically activate the first voltage regulator unit and the second voltage regulator unit, which will work simultaneously in parallel.

2. The method for utilizing natural gas pressure energy and cold energy according to claim 1, characterized in that, The differential pressure generator set includes a pneumatic isolation valve, a filter, a pressure sensor, a temperature sensor, an electric butterfly valve, a planar turbine expander, a generator and grid connection cabinet, and a check valve. The pneumatic isolation valve, filter, pressure sensor, temperature sensor, and electric butterfly valve are sequentially connected to the natural gas inlet of the planar turbine expander. The generator and grid connection cabinet are directly connected to the output shaft of the planar turbine expander to obtain sufficient torque required for power generation. The natural gas outlet of the planar turbine expander is sequentially connected to the pressure sensor, temperature sensor, pneumatic isolation valve, and check valve.

3. The method for utilizing natural gas pressure energy and cold energy according to claim 2, characterized in that, The filter is a cone-shaped filter used for coarse filtration to prevent large particles of impurities from damaging the equipment.

4. The method for utilizing natural gas pressure energy and cold energy according to claim 1, characterized in that, The heat exchange unit includes a single-tube heat exchanger. The natural gas outlet of the differential pressure generator set is connected to the natural gas inlet of the single-tube heat exchanger through a pressure pipeline element. The air conditioning cooling water inlet is connected to the inlet of the single-tube heat exchanger in sequence through a pressure pipeline element, consisting of a temperature sensor, a pressure sensor, and a valve group. The outlet of the single-tube heat exchanger is connected to the air conditioning chilled water inlet in sequence through a pressure pipeline element, consisting of a temperature sensor, a temperature switch, a flow switch, and a valve group. The natural gas, heated by the heat exchange, is connected in parallel with the expansion compressor bypass pressure stabilizing unit through the outlet of the single-tube heat exchanger and then connected to other downstream gas-consuming equipment.

5. The method for utilizing natural gas pressure energy and cold energy according to claim 1, characterized in that, The first pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve. The second pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve. The third pressure regulating unit is connected in series with a pneumatic isolation valve, a pressure gauge, a monitoring pressure regulator including a shut-off valve, a working pressure regulator, a pressure gauge, and a pneumatic isolation valve. Compressed air passes through pressure piping components respectively... The pneumatic actuators supplied to the first, second, and third pressure stabilizing and regulating units serve as the valve torque input source to control the opening and closing of the pneumatic isolation valve. The monitoring and working pressure regulators and shut-off valves in the first, second, and third pressure stabilizing and regulating units respectively use pressure taps on the natural gas pipeline. After comparing the pressure value set by the spring inside the regulator, the valve opening is automatically adjusted, thereby achieving precise pressure regulation.

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