Low-carbon emission pipeline combustion-driven compression system

Abstract

This invention relates to the field of exhaust gas utilization technology, and more particularly to a low-carbon emission pipeline combustion-driven compression system. It includes a gas pipeline, a gas turbine, a first centrifugal compressor, and a second centrifugal compressor. The gas pipeline is connected to both the gas turbine and the first centrifugal compressor via piping. The first and second centrifugal compressors are also connected via piping. The gas turbine and the first centrifugal compressor are connected via a first gearbox. The second centrifugal compressor drives the gas pipeline itself to transport gas. A hydrogen separation device is installed between the gas pipeline and the gas turbine. A waste heat recovery device is installed at the output end of the gas turbine. An expander is installed at the tail end of the waste heat recovery device, and the expander is connected to the second centrifugal compressor via a second gearbox. This invention improves the utilization rate of waste heat from the gas turbine, enables waste heat to directly drive the compressor for gas transport within the pipeline, enhances the compressor's boosting capacity, achieves clean combustion, and reduces carbon emissions.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas utilization technology, and in particular to a low-carbon emission pipeline combustion-driven compression system. Background Technology

[0002] With the development of gas pipelines in my country, natural gas booster equipment has gone through a development process from being dominated by reciprocating compressor units driven by natural gas engines to being dominated by centrifugal compressor units driven by gas turbines or electric motors.

[0003] Gas turbines use pipeline-transported natural gas as fuel. When the turbine performs work, it draws in air from the atmosphere, compresses it to a certain pressure, and then sends it to the combustion chamber to mix and burn with injected fuel, forming high-temperature, high-pressure gas exceeding 1000°C. This gas then expands and performs work, driving the turbine rotor. During the gas turbine's work process, only about 40% of the energy is converted into mechanical energy and utilized. After this first-stage utilization, the temperature of the high-temperature gas drops to approximately 400°C–520°C before being discharged into the atmosphere. The discharged high-temperature flue gas still contains a large amount of energy, with an enthalpy of approximately 452–481 kJ / m³. To fully utilize this remaining large amount of heat energy, a second-stage utilization can be implemented, namely, utilizing the waste heat discharged from the gas turbine. This reduces the significant energy waste resulting from directly venting the flue gas into the atmosphere and can also greatly reduce exhaust emissions, resulting in significant economic and social benefits.

[0004] Currently, the comprehensive utilization of gas turbine thermal energy mainly includes several methods such as waste heat heating, waste heat cooling, and waste heat power generation.

[0005] Waste heat heating technology involves recovering the high-temperature flue gas from gas turbines using a waste heat hot water boiler. This heat is then exchanged with water to produce 95°C hot water, providing heating for both domestic and industrial use at the station, primarily for station heating. This method requires relatively less equipment investment and land area, but the waste heat utilization rate is low, with only about 1 / 40 of the waste heat energy being utilized. The remaining heat is still emitted with the gas flue gas, resulting in relatively low economic benefits. Waste heat refrigeration technology utilizes the waste heat from gas turbine flue gas to exchange with a medium, which drives a compression or absorption refrigeration machine. This method requires more investment than waste heat heating, but most of the heat energy remains unutilized, and its application is significantly limited by the presence of users in the vicinity of the station requiring cooling energy. Neither of these methods is a direct or efficient way to utilize waste heat. For example, Chinese patent (CN218624441U) discloses a waste heat utilization device for gas turbines, and Chinese patent (CN112943454A) discloses a waste heat utilization system for gas turbines. Both of these patents are about how to improve the waste heat utilization rate. However, waste heat can only be utilized once, so there is still room for improvement in the waste heat utilization rate. Moreover, none of the above patents have solved the problem of flue gas emissions, which will continue to cause air pollution.

[0006] Waste heat power generation from gas turbines involves exchanging heat between the high-temperature flue gas discharged from the gas turbine and a heat exchanger, converting some of the flue gas's waste heat into the heat of the heat exchanger's steam. The flue gas temperature drops from approximately 500°C to approximately 200°C before being discharged. The steam then enters a steam turbine or expander to perform work, driving a generator to generate electricity. However, some waste heat remains unutilized, leading to resource waste and environmental pollution. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a low-carbon emission pipeline combustion-driven compression system, which improves the utilization rate of waste heat from gas turbines, realizes the direct drive of waste heat to the compressor for gas transmission in the pipeline itself, enhances the compressor's boosting capacity, achieves clean combustion, and reduces carbon emissions.

[0008] This invention provides a low-carbon emission pipeline combustion-driven compression system, including a gas pipeline, a gas turbine, a first centrifugal compressor, and a second centrifugal compressor. The gas pipeline is connected to the gas turbine and the first centrifugal compressor via pipelines. The first and second centrifugal compressors are connected to each other via pipelines. The gas turbine and the first centrifugal compressor are connected via a first gearbox. The gas turbine drives the first centrifugal compressor to transport gas from the gas pipeline to the second centrifugal compressor. The second centrifugal compressor drives the gas pipeline itself to transport gas. A hydrogen separation device is installed between the gas pipeline and the gas turbine. A waste heat recovery device is installed at the output end of the gas turbine. An expander is installed at the tail end of the waste heat recovery device. The expander is connected to the second centrifugal compressor via the second gearbox.

[0009] A hydrogen separation unit extracts a small portion of the gas from the gas pipeline and separates hydrogen from the natural gas. The natural gas is used to start the gas turbine, and the energy generated by its combustion ensures a safe and stable start-up. After the gas turbine starts normally, hydrogen is switched to be the main fuel, thus reducing carbon emissions. The gas turbine drives a first centrifugal compressor, which in turn drives a second centrifugal compressor. Both compressors pressurize the gas in the pipeline for transport. A waste heat recovery unit recovers the high-temperature flue gas generated by the gas turbine and uses it to power an expander, which in turn provides power to the second centrifugal compressor, thus achieving high-temperature flue gas recovery and utilization and reducing air pollution.

[0010] The waste heat recovery device includes a waste heat boiler, a thermal oil tank, a heat exchanger assembly, an organic matter tank, and an air cooler. The waste heat boiler is connected to the output end of the gas turbine via pipelines. The waste heat boiler, heat exchanger assembly, and thermal oil tank are connected end-to-end in sequence to form a thermal oil loop. The organic matter tank, heat exchanger assembly, expander, and air cooler are connected end-to-end in sequence to form an organic matter loop. The waste heat boiler absorbs the high-temperature flue gas generated by the gas turbine. The thermal oil tank is filled with thermal oil, which enters the waste heat boiler and is heated by the high-temperature flue gas before entering the heat exchanger assembly. The organic matter tank is filled with organic media, which enters the heat exchanger assembly and is heated by the high-temperature thermal oil. The high-temperature organic media flows into the expander, driving the expander to perform work. The air cooler cools the organic media after it has performed work, allowing it to flow back into the organic matter tank, forming an organic media loop. The high-temperature thermal oil heats the organic media and then flows back into the thermal oil tank, forming an oil loop. This allows the organic media and thermal oil to be recycled, saving resources. The heat transfer oil tank can be used to regulate the volume expansion of the heat transfer oil. The air cooler condenses the organic medium, and the condensed liquid is collected in the organic matter tank.

[0011] The advantages of using heat transfer oil to heat organic media are: (1) To protect the thermal stability of the organic working medium and prevent it from thermally decomposing or oxidizing at high temperatures, thus affecting system performance and safety. As an intermediate heat transfer medium, heat transfer oil can withstand high temperatures and will not degrade or deteriorate at high temperatures. It can control the heating temperature of the organic medium so that it does not exceed its critical temperature or decomposition temperature; (2) To improve heat exchange efficiency and reduce heat loss. Heat transfer oil has a high specific heat capacity and thermal conductivity, which can achieve a large heat transfer with a small temperature difference, reduce the size and cost of the heat exchanger, and no phase change or expansion of the substance will occur during the heat transfer process.

[0012] A regenerator is installed between the organic matter tank and the heat exchanger assembly, and the regenerator is connected to the expander. The organic medium in the organic matter tank first enters the regenerator. The expander generates a large amount of heat while performing work. The heat generated by the expander is recovered and used to preheat the organic medium in the regenerator, thereby increasing the temperature of the organic medium and making full use of energy to improve working efficiency.

[0013] An organic matter pump is installed between the organic matter tank and the regenerator. The organic matter pump actively transports the organic medium from the organic matter tank to the regenerator, promoting the circulation of the organic medium.

[0014] An oil pump is installed between the waste heat boiler and the thermal oil tank. The oil pump actively transports the thermal oil in the thermal oil tank to the regenerator, promoting the circulation of the thermal oil.

[0015] The heat exchanger assembly includes a preheater, an evaporator, and a superheater, which are connected in sequence. The organic medium is preheated to near its boiling point in the heat exchanger, then evaporates in the evaporator, and subsequently superheats in the superheater. Finally, at the operating temperature and pressure, the organic medium enters the expander to perform work. The preheater, evaporator, and superheater achieve the heating of the organic medium, bringing it to its working state.

[0016] The preheater and superheater are both shell-and-tube structures, comprising a tube side and a shell side. The tube side and shell side separate the organic medium from the heat transfer oil while simultaneously allowing the heat from the heat transfer oil to be smoothly transferred to the organic medium.

[0017] The shell side of the preheater and superheater is used for the flow of heat transfer oil, while the tube side is used for the flow of organic media. This ensures that the heat transfer oil fully encapsulates the organic media, maximizing the transfer of heat to the organic media.

[0018] The hydrogen separation device includes a hydrogen separator. The input end of the hydrogen separator is connected to a gas pipeline. The output end of the hydrogen separator is equipped with a hydrogen storage tank and a natural gas storage tank, which are connected in parallel. The output end of the hydrogen storage tank is connected to a gas turbine. A first valve is installed between the hydrogen storage tank and the gas turbine. The output end of the natural gas storage tank is connected to the gas turbine, and a second valve is installed between the natural gas storage tank and the gas turbine. The hydrogen separator separates hydrogen from the natural gas and stores it in the hydrogen storage tank, while the natural gas is stored in the natural gas storage tank. When the gas turbine is started, the second valve is opened first, using natural gas as the primary fuel to drive the gas turbine. Once the gas turbine has started normally, the second valve is closed, and the first valve is opened, switching to hydrogen as the main fuel for the gas turbine, thereby reducing carbon emissions.

[0019] A third valve is installed between the hydrogen separator and the gas pipeline. The third valve controls the connection and disconnection between the gas pipeline and the hydrogen separator.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This invention separates hydrogen from natural gas by setting up a hydrogen separation device, enabling the use of natural gas as the primary fuel in the later stages, thereby reducing carbon emissions. By setting up a waste heat recovery device, the high-temperature flue gas generated by the gas turbine is recovered and used to power the expander, increasing the power output of the second centrifugal compressor and enhancing its pressurization capacity. This achieves the recovery and utilization of high-temperature flue gas and reduces air pollution.

[0022] 2. The waste heat recovery device includes a waste heat boiler, a thermal oil tank, a heat exchanger assembly, an organic matter tank, and an air cooler. The waste heat boiler is connected to the output end of the gas turbine via pipelines. The waste heat boiler, heat exchanger assembly, and thermal oil tank are connected end-to-end in sequence to form a thermal oil loop. The organic matter tank, heat exchanger assembly, expander, and air cooler are connected end-to-end in sequence to form an organic matter loop. The waste heat boiler absorbs the high-temperature flue gas generated by the gas turbine. The thermal oil tank is filled with thermal oil, which enters the waste heat boiler and is heated by the high-temperature flue gas before entering the heat exchanger assembly. The organic matter tank is filled with organic media, which enters the heat exchanger assembly and is heated by the high-temperature thermal oil. The high-temperature organic media flows into the expander, driving the expander to perform work. The air cooler cools the organic media after it has performed work, allowing it to flow back into the organic matter tank, forming an organic media loop. The high-temperature thermal oil heats the organic media and then flows back into the thermal oil tank, forming an oil loop. This allows the organic media and thermal oil to be recycled, saving resources.

[0023] 3. The heat exchanger assembly includes a preheater, an evaporator, and a superheater, which are connected sequentially. The organic medium is preheated to near its boiling point in the heat exchanger, then evaporates in the evaporator, and subsequently superheats in the superheater. Finally, at the operating temperature and pressure, the organic medium enters the expander to perform work. The preheater, evaporator, and superheater achieve the heating of the organic medium, bringing it to its working state. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the workflow of the present invention.

[0025] In the diagram: 1. Gas pipeline; 2. Third valve; 3. Hydrogen separator; 4. Natural gas storage tank; 5. Hydrogen storage tank; 6. First valve; 7. Gas turbine; 8. First gearbox; 9. First centrifugal compressor; 10. Second valve; 11. Second centrifugal compressor; 12. Expander; 13. Thermal oil tank; 14. Superheater; 15. Evaporator; 16. Preheater; 17. Oil pump; 18. Regenerator; 19. Organic matter pump; 20. Waste heat boiler; 21. Organic matter tank; 22. Air cooler. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments:

[0027] Example 1

[0028] like Figure 1As shown, the low-carbon emission pipeline combustion-driven compression system of the present invention includes a gas pipeline 1, a gas turbine 7, a first centrifugal compressor 9, and a second centrifugal compressor 11. There are two gas turbines 7 and two first centrifugal compressors 9. The gas pipeline 1 is connected to both the gas turbine 7 and the first centrifugal compressor 9 via pipelines. The first centrifugal compressor 9 and the second centrifugal compressor 11 are connected via pipelines. The gas turbine 7 and the first centrifugal compressor 9 are connected via a first gearbox 8. The gas turbine 7 drives the first centrifugal compressor 9 to transport gas from the gas pipeline 1 to the second centrifugal compressor 11. The second centrifugal compressor 11 drives the gas pipeline 1 itself to transport gas. A hydrogen separation device is installed between the gas pipeline 1 and the gas turbine 7. A waste heat recovery device is installed at the output end of the gas turbine 7. An expander 12 is installed at the tail end of the waste heat recovery device. The expander 12 is connected to the second centrifugal compressor 11 via the second gearbox.

[0029] The waste heat recovery device includes a waste heat boiler 20, a thermal oil tank 13, a heat exchanger assembly, an organic matter tank 21, and an air cooler 22. The waste heat boiler 20 is connected to the output end of the gas turbine 7 via pipelines. The waste heat boiler 20, the heat exchanger assembly, and the thermal oil tank 13 are connected end-to-end in sequence. An oil pump 17 is installed between the waste heat boiler 20 and the thermal oil tank 13 to form a thermal oil circuit. The organic matter tank 21, the heat exchanger assembly, the expander 12, and the air cooler 22 are connected end-to-end in sequence. A regenerator 18 is installed between the organic matter tank 21 and the heat exchanger assembly, and the regenerator 18 is connected to the expander 12. An organic matter pump 19 is installed between the organic matter tank 21 and the regenerator 18 to form an organic matter circuit.

[0030] The heat exchanger assembly includes a preheater 16, an evaporator 15, and a superheater 14, which are connected in sequence. The preheater 16 and superheater 14 are shell-and-tube structures, each including a tube side and a shell side. The shell side of the preheater 16 and superheater 14 is used for the flow of heat transfer oil, while the tube side is used for the flow of organic media.

[0031] The hydrogen separation unit includes a hydrogen separator 3. The input end of the hydrogen separator 3 is connected to the gas transmission pipeline 1. The output end of the hydrogen separator 3 is equipped with a hydrogen storage tank 5 and a natural gas storage tank 4, which are connected in parallel. The output end of the hydrogen storage tank 5 is connected to a gas turbine 7. A first valve 6 is installed between the hydrogen storage tank 5 and the gas turbine 7. The output end of the natural gas storage tank 4 is connected to the gas turbine 7. A second valve 10 is installed between the natural gas storage tank 4 and the gas turbine 7. A third valve 2 is installed between the hydrogen separator 3 and the gas transmission pipeline 1.

[0032] Work process:

[0033] The third valve 2 and the second valve 10 are opened to drive the gas turbine 7 using natural gas as the main fuel. After the gas turbine 7 starts normally, the second valve 10 is closed and the first valve 6 is opened to switch to hydrogen as the main fuel for the gas turbine 7 to maintain operation. The waste heat boiler 20 absorbs the high-temperature flue gas generated by the gas turbine 7. The oil pump 17 draws the heat transfer oil from the heat transfer oil tank 13 into the waste heat boiler 20, where it is heated by the high-temperature flue gas and then enters the preheater 16, evaporator 15, and superheater 14 in sequence. The organic matter pump 19 draws the organic medium from the organic matter tank 21 into the regenerator 18, which then enters the preheater 16, evaporator 15, and superheater 14 in sequence. The organic medium is preheated to near its boiling point temperature by the heat exchanger, then evaporates in the evaporator 15, and is superheated in the superheater 14. Finally, at the operating temperature and pressure, the organic medium enters the expander 12 to do work, which provides power for the operation of the second centrifugal compressor 11.

[0034] The descriptions of the orientation and relative positional relationships of the structures in this invention, such as front, back, left, right, up, and down, do not constitute a limitation of this invention, but are merely for the convenience of description.

Claims

1. A low-carbon emission pipeline combustion-driven compression system, characterized in that, The system includes a gas pipeline (1), a gas turbine (7), a first centrifugal compressor (9), and a second centrifugal compressor (11). The gas pipeline (1) is connected to the gas turbine (7) and the first centrifugal compressor (9) through pipelines. The first centrifugal compressor (9) and the second centrifugal compressor (11) are connected through pipelines. The gas turbine (7) and the first centrifugal compressor (9) are connected through a first gearbox (8). The gas turbine (7) drives the first centrifugal compressor (9) to transport the gas in the gas pipeline (1) to the second centrifugal compressor (11). The second centrifugal compressor (11) is used to drive the gas pipeline (1) to transport gas. A hydrogen separation device is installed between the gas pipeline (1) and the gas turbine (7). A waste heat recovery device is installed at the output end of the gas turbine (7). An expander (12) is installed at the tail end of the waste heat recovery device. The expander (12) is connected to the second centrifugal compressor (11) through the second gearbox.

2. The low-carbon emission pipeline combustion-driven compression system according to claim 1, characterized in that, The waste heat recovery device includes a waste heat boiler (20), a heat transfer oil tank (13), a heat exchanger group, an organic matter tank (21), and an air cooler (22). The waste heat boiler (20) is connected to the output end of the gas turbine (7) through a pipeline. The waste heat boiler (20), the heat exchanger group, and the heat transfer oil tank (13) are connected end to end in sequence to form a heat transfer oil circuit. The organic matter tank (21), the heat exchanger group, the expander (12), and the air cooler (22) are connected end to end in sequence to form an organic matter circuit.

3. The low-carbon emission pipeline combustion-driven compression system according to claim 2, characterized in that, A regenerator (18) is installed between the organic matter tank (21) and the heat exchanger assembly, and the regenerator (18) is connected to the expander (12).

4. The low-carbon emission pipeline combustion-driven compression system according to claim 3, characterized in that, An organic matter pump (19) is installed between the organic matter tank (21) and the regenerator (18).

5. The low-carbon emission pipeline combustion-driven compression system according to claim 2, characterized in that, An oil pump (17) is installed between the waste heat boiler (20) and the heat transfer oil tank (13).

6. The low-carbon emission pipeline combustion-driven compression system according to claim 2, characterized in that, The heat exchanger assembly includes a preheater (16), an evaporator (15), and a superheater (14), which are connected in sequence.

7. The low-carbon emission pipeline combustion-driven compression system according to claim 6, characterized in that, The preheater (16) and superheater (14) are shell-and-tube structures, each including a tube side and a shell side.

8. The low-carbon emission pipeline combustion-driven compression system according to claim 7, characterized in that, The shell side of the preheater (16) and superheater (14) is used for the flow of heat transfer oil, and the tube side is used for the flow of organic media.

9. The low-carbon emission pipeline combustion-driven compression system according to any one of claims 1-8, characterized in that, The hydrogen separation device includes a hydrogen separator (3), the input end of which is connected to a gas pipeline (1), and the output end of the hydrogen separator (3) is provided with a hydrogen storage tank (5) and a natural gas storage tank (4). The hydrogen storage tank (5) and the natural gas storage tank (4) are connected in parallel. The output end of the hydrogen storage tank (5) is connected to a gas turbine (7). A first valve (6) is provided between the hydrogen storage tank (5) and the gas turbine (7). The output end of the natural gas storage tank (4) is connected to the gas turbine (7). A second valve (10) is provided between the natural gas storage tank (4) and the gas turbine (7).

10. The low-carbon emission pipeline combustion-driven compression system according to claim 9, characterized in that, A third valve (2) is installed between the hydrogen separator (3) and the gas pipeline (1).

Images