Natural gas pressure reduction power generation and clean energy cascade heating fuel gas system

Abstract

The utility model discloses a natural gas decompression power generation and clean energy cascade heating fuel gas system which comprises a first heat exchanger, a fuel gas generator set, a vaporizer and a shallow geothermal energy system which are sequentially communicated through a loop pipeline. A buried pipe of the shallow geothermal energy system is buried underground, and the buried pipe and a second heat exchanger form a circulating pipeline so as to extract underground soil heat into the second heat exchanger; after being input into the first heat exchanger for heat exchange, the secondary high-pressure natural gas is output to the gas generator set for decompression power generation, the vaporizer can conduct primary heating and heat compensation on the decompressed natural gas, the second heat exchanger conducts heat exchange on the heated natural gas, and after heat exchange, the secondary high-pressure natural gas enters the first heat exchanger for secondary heat exchange and then is output. According to the technical scheme, gradient heating and reheating of the natural gas are achieved, energy waste during pressure reduction of the natural gas is avoided, and the system is safe, environmentally friendly, energy-saving, efficient and capable of meeting the heating requirement of the natural gas.

Description

Technical Field

[0001] The utility model relates to the technical field of clean energy power generation, in particular to a natural gas pressure-reducing power generation and clean energy cascade heating gas system. Background Art

[0002] Natural gas is an important energy resource, widely used in industrial production, residential heating and power generation. In recent years, the rapid development of the national economy has provided continuous impetus for the steady and rapid development of my country's power industry. Natural gas generators have become the main equipment of the power industry by virtue of energy saving, high efficiency and environmental protection.

[0003] During the transportation of natural gas, it needs to be gradually reduced by a pressure reducing valve to meet the gas pressure requirements of users, and there will be a large amount of energy waste in the process of reducing pressure. In order to effectively utilize the energy released by natural gas pressure reduction, gas generator sets are used for effective utilization. After the gas generator set reduces pressure to generate electricity, the temperature of natural gas drops greatly, often below -30℃, which is seriously lower than the temperature of natural gas connected to the sub-high pressure pipeline network, that is, below 0℃. Low-temperature natural gas cannot be directly connected to the sub-high pressure pipeline network. Therefore, it is necessary to supplement the heat of the low-temperature natural gas after pressure reduction to meet the temperature requirements of entering the sub-high pressure pipeline network.

[0004] Reheating natural gas after depressurization is of great significance for improving the utilization efficiency of natural gas and reducing energy waste. Conventional natural gas reheating methods such as burner reheating and electric heating have problems such as pollution, insufficient safety performance and high operating costs. Therefore, there is a lack of a facility that can quickly and efficiently heat up the natural gas after the gas generator set is depressurized for power generation. Utility Model Content

[0005] In view of the above problems, the utility model provides a natural gas decompression power generation and clean energy cascade heating gas system, which absorbs atmospheric heat through a vaporizer to heat up the low-temperature natural gas after decompression power generation, and uses the heat provided by a shallow geothermal energy system to heat up the natural gas for a second time, and then exchanges heat with the newly input natural gas after the second heating, to achieve cascade heating and reheating of the natural gas, thereby solving the energy waste during natural gas decompression, and at the same time solving the problem of the generator set being unable to be connected to the sub-high pressure pipeline network due to the low temperature caused by the small internal energy of the natural gas after decompression power generation, and requiring rapid heating and reheating. The system is safe, environmentally friendly, energy-saving, and efficient, and can meet the heating needs of natural gas.

[0006] To achieve the above-mentioned purpose, the utility model provides a natural gas pressure-reducing power generation and clean energy cascade heating gas system, comprising a first heat exchanger, a gas generator set, a vaporizer and a shallow geothermal energy system which are sequentially connected through a loop pipeline;

[0007] The shallow geothermal energy system comprises a buried pipe and a second heat exchanger, wherein the buried pipe is buried underground, and the buried pipe and the second heat exchanger form a circulation pipeline to extract heat from underground soil into the second heat exchanger;

[0008] After the sub-high-pressure natural gas is input into the first heat exchanger for heat exchange, it can be output to the gas generator set for reduced-pressure power generation. The vaporizer can heat up the reduced-pressure natural gas once, and the second heat exchanger can heat-exchange and heat-increase the natural gas after the first heating. The natural gas after heat exchange and temperature increase can enter the first heat exchanger for another heat exchange and then be output.

[0009] In the above technical solution, preferably, the shallow geothermal energy system further includes a water replenishment component and a first circulation pump group;

[0010] The water replenishment assembly includes a water softener and a water replenishment tank, the input end of the water softener is connected to the tap water network, the output end of the water softener is connected to the input end of the water replenishment tank, and the output end of the water replenishment tank is connected to the circulation pipeline to replenish water to the circulation pipeline;

[0011] The first circulation pump group is arranged on the circulation pipeline, and the first circulation pump group drives the buried pipe and the second heat exchanger to realize geothermal water circulation.

[0012] In the above technical solution, preferably, the shallow geothermal energy system further comprises a valve assembly, and the valve assembly comprises a first stop valve, a first bypass valve and / or a second bypass valve;

[0013] The first stop valve is arranged on the circulation pipeline, and the water circulation heat exchange of the shallow geothermal energy system can be closed by the first stop valve;

[0014] The first bypass valve is arranged in parallel on the circulation pipeline outside the second heat exchanger, and the geothermal water is circulated through the first bypass valve instead of being heat exchanged through the second heat exchanger by switching the first bypass valve.

[0015] The second bypass valve is arranged in parallel on the loop pipeline outside the second heat exchanger. By switching the second bypass valve, the natural gas circulates through the second bypass valve instead of passing through the second heat exchanger for heat exchange.

[0016] In the above technical solution, preferably, the shallow geothermal energy system also includes a fresh air unit, which is arranged in parallel on the circulation pipeline. The fresh air unit can release the cold energy in the buried pipe into the atmospheric environment and supplement the heat in the outdoor environment into the buried pipe.

[0017] In the above technical solution, preferably, the shallow geothermal energy system also includes a second stop valve, which is arranged on the input and output pipelines of the fresh air unit, and the heat interaction between the fresh air unit and the buried pipe can be closed by the second stop valve.

[0018] In the above technical solution, preferably, the gas generator set includes a heat dissipation cooling water pipeline, a third heat exchanger is arranged on the circulation pipeline, the heat dissipation cooling water pipeline is connected to the third heat exchanger through a second circulation pump group, and the second circulation pump group circulates the cooling water of the gas generator set to the third heat exchanger to transfer the working heat of the gas generator set to the shallow geothermal energy system.

[0019] In the above technical solution, preferably, the gas generator set also includes a high-level water tank, the input end of the high-level water tank is connected to the tap water network, and the output end of the high-level water tank is connected to the cooling water pipeline of the second circulation pump group to replenish water to the heat dissipation cooling water pipeline.

[0020] In the above technical solution, preferably, a vaporization stop valve is provided at the input end of the vaporizer, and the delivery of the sub-high pressure natural gas to the vaporizer can be closed by the vaporization stop valve.

[0021] Compared with the prior art, the utility model has the following beneficial effects: the low-temperature natural gas after decompression and power generation is heated once by absorbing atmospheric heat through the vaporizer, the natural gas is heated for a second time by using the heat provided by the shallow geothermal energy system, and then the natural gas after the second heating is exchanged with the newly input natural gas to achieve step-by-step heating and reheating of the natural gas, thereby solving the energy waste during the decompression of the natural gas and the problem that the generator set cannot be connected to the sub-high pressure pipeline network due to the low temperature caused by the small internal energy of the natural gas after decompression and power generation, and the system is safe, environmentally friendly, energy-saving and efficient, and can meet the heating needs of the natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The utility model discloses a structural schematic diagram of a natural gas pressure-reducing power generation and clean energy cascade heating gas system according to an embodiment of the utility model.

[0023] In the figure, the corresponding relationship between each component and the reference numeral is as follows:

[0024] 1. Natural gas inlet valve; 2. First heat exchanger; 3. Regulating valve group; 4. Generator group; 5. High-level water tank; 6. Second circulation pump group; 7. Vaporization stop valve; 8. Vaporizer; 9. Buried pipe; 10. Water softener; 11. Water make-up tank; 12. First circulation pump group; 13. Third heat exchanger; 14. Second bypass valve; 15. Second heat exchanger; 16. First bypass valve; 17. First stop valve; 18. Second stop valve; 19. Fresh air unit. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] The utility model is further described in detail below in conjunction with the accompanying drawings:

[0027] like Figure 1 As shown, a natural gas pressure-reducing power generation and clean energy step-by-step heating gas system provided by the utility model comprises a first heat exchanger 2, a gas generator set 4, a vaporizer 8 and a shallow geothermal energy system which are sequentially connected through a loop pipeline;

[0028] The shallow geothermal energy system includes a buried pipe 9 and a second heat exchanger 15. The buried pipe 9 is buried underground. The buried pipe 9 and the second heat exchanger 15 form a circulation pipeline to extract the heat of the underground soil into the second heat exchanger 15.

[0029] After the sub-high-pressure natural gas is input into the first heat exchanger 2 for heat exchange, it can be output to the gas generator set 4 for reduced-pressure power generation. The vaporizer 8 can heat up the reduced-pressure natural gas once for supplementary heat. The second heat exchanger 15 can heat-exchange and heat-increase the natural gas after the first temperature increase. The natural gas after heat exchange and temperature increase can enter the first heat exchanger 2 for another heat exchange and then be output.

[0030] In this embodiment, the system mainly converts sub-high pressure natural gas into low-temperature and low-pressure sub-high pressure natural gas after it generates electricity through a generator set. Since it cannot directly enter the sub-high pressure pipeline network due to its low temperature in the cold winter season, it needs to be heated.

[0031] Specifically, the vaporizer 8 absorbs atmospheric heat to heat up the low-temperature natural gas after decompression and power generation. When the supplementary heat still does not meet the temperature requirement, the heat provided by the shallow geothermal energy system is used to heat up the natural gas for a second time, and then the natural gas after the second heating is exchanged with the newly input natural gas. If the natural gas temperature does not meet the requirement for entering the sub-high-pressure pipeline network, the first heat exchanger 2 uses the sub-high-pressure gas to supplement heat again to meet the target temperature requirement, thereby realizing the step-by-step heating and reheating of the natural gas, solving the energy waste during the decompression of the natural gas, and solving the problem of the generator set being unable to be connected to the sub-high-pressure pipeline network due to the low temperature caused by the small internal energy of the natural gas after decompression and power generation, and the need for rapid heating and reheating. The system is safe, environmentally friendly, energy-saving, and efficient, and can meet the heating requirements of the natural gas.

[0032] Specifically, a shallow buried pipe 9 is arranged outdoors underground. The buried pipe 9 is composed of several buried pipes 9 connected in parallel. All the equipment on the ground is built in the machine room. The pipeline of the buried pipe 9 is connected to the equipment room and forms a loop with the second heat exchanger 15.

[0033] The underground pipe 9 is connected to the second heat exchanger 15 through the circulation pipeline and the natural gas pipeline. The circulating water in the underground pipe 9 exchanges heat with the natural gas in the second heat exchanger 15, and then exchanges heat with the newly input natural gas through the first heat exchanger 2 to raise the temperature to a preset temperature range before being directly transported to the secondary high-pressure pipeline network. If the temperature of the heated natural gas is higher than the requirement of the secondary high-pressure pipeline network, the temperature of the secondary high-pressure gas can be reversely heated through the heat exchanger, and this temperature increase can also improve the working efficiency of the generator set.

[0034] In the above embodiment, preferably, the shallow geothermal energy system further comprises a water replenishment component and a first circulation pump group;

[0035] The water replenishment assembly includes a water softener 10 and a water replenishment tank 11. The input end of the water softener 10 is connected to the tap water network, the output end of the water softener 10 is connected to the input end of the water replenishment tank 11, and the output end of the water replenishment tank 11 is connected to the circulation pipeline to replenish water to the circulation pipeline;

[0036] The first circulation pump group 12 is disposed on the circulation pipeline, and the first circulation pump group 12 drives the buried pipe 9 and the second heat exchanger 15 to realize the circulation of geothermal water.

[0037] In this embodiment, the system's water replenishment is connected to the water softener 10 through the tap water network, and then the softened water is replenished into the high-position water replenishment tank 11, and the water replenishment tank 11 replenishes the entire shallow geothermal energy system.

[0038] In the above embodiment, preferably, the shallow geothermal energy system further comprises a valve assembly, and the valve assembly comprises a first stop valve 17, a first bypass valve 16 and / or a second bypass valve 14;

[0039] The first stop valve 17 is arranged on the circulation pipeline, and the water circulation heat exchange of the shallow geothermal energy system can be closed by the first stop valve 17;

[0040] The first bypass valve 16 is arranged in parallel on the circulation pipeline outside the second heat exchanger 15. By switching the first bypass valve 16, the geothermal water circulates through the first bypass valve 16 instead of passing through the second heat exchanger 15 for heat exchange.

[0041] The second bypass valve 14 is arranged in parallel on the loop pipeline outside the second heat exchanger 15 . By switching the second bypass valve 14 , the natural gas circulates through the second bypass valve 14 instead of passing through the second heat exchanger 15 for heat exchange.

[0042] Specifically, in non-cold seasons, when the natural gas does not need to be heated up by the buried pipe 9, the first bypass valve 16 can be switched to allow the natural gas to directly enter the first heat exchanger 2 instead of entering the second heat exchanger 15 for heat exchange.

[0043] In the above embodiment, preferably, the shallow geothermal energy system also includes a fresh air unit 19, which is arranged in parallel on the circulation pipeline. The fresh air unit 19 can release the cold energy in the buried pipe 9 into the atmospheric environment and supplement the heat in the outdoor environment into the buried pipe 9.

[0044] In this embodiment, the shallow geothermal energy system extracts heat from the underground soil for a long time. If the underground heat cannot be effectively supplemented, the soil temperature at the outdoor buried pipe will drop sharply, causing the entire outdoor shallow geothermal energy system to form a cold accumulation, affecting the system operation effect. To solve this problem, a fresh air unit 19 can be added to the shallow geothermal energy system, so that the fresh air unit 19, the buried pipe 9 and the first circulation pump unit 12 form a loop.

[0045] For example, when the ambient temperature is higher than 26°C in spring, summer and autumn, the first circulation pump group 12 is used to drive the circulating water through the fresh air unit 19 to release the cold energy accumulated in the buried pipe 9 into the atmosphere, and to supplement the heat in the outdoor environment into the soil of the buried pipe 9, thereby effectively alleviating the cold accumulation in the stratum.

[0046] In the above embodiment, preferably, the shallow geothermal energy system also includes a second stop valve 18, which is arranged on the input and output pipelines of the fresh air unit 19. The second stop valve 18 can close the heat interaction between the fresh air unit 19 and the buried pipe 9.

[0047] Specifically, when the fresh air unit 19 is not needed, the system can be closed by the second valve, so as to achieve stable operation of the natural gas heating and reheating system.

[0048] In the above embodiment, preferably, the gas generator set 4 includes a heat dissipation cooling water pipeline, a third heat exchanger 13 is arranged on the circulation pipeline, the heat dissipation cooling water pipeline is connected to the third heat exchanger 13 through a second circulation pump group, and the second circulation pump group circulates the cooling water of the gas generator set 4 to the third heat exchanger 13 to transfer the working heat of the gas generator set 4 to the shallow geothermal energy system.

[0049] In this embodiment, the gas generator set 4 generates a large amount of heat during the power generation process. In order to dissipate the heat of the gas generator set 4 so that it can operate in normal working conditions, the water temperature of the cooling loop of the generator set is usually controlled at 25-80°C. Generally, the gas generator set 4 will connect the cooling water in the cooling system to the outdoor cooling tower for heat dissipation, which not only causes energy waste, but also has an adverse effect on the thermal effect of the environment. In order to improve the heating efficiency of natural gas, the heat dissipation cooling water pipeline of the gas generator set 4 can be connected to the shallow geothermal energy system, and the heat generated by the gas generator set 4 when working can be supplemented to the shallow geothermal energy system to realize waste heat collection as another supplementary heat source for natural gas, thereby further improving the temperature of natural gas and greatly increasing the system heat supplement and work efficiency. The cooling system of the gas generator set 4 is changed to a pipeline directly connected to the buried pipe 9 system to supplement the heat of the shallow geothermal energy system, achieving the dual effects of cooling the gas generator set 4 and heating the shallow geothermal energy system.

[0050] In the above embodiment, preferably, the gas generator set 4 also includes a high-level water tank 5, the input end of the high-level water tank 5 is connected to the tap water network, and the output end of the high-level water tank 5 is connected to the cooling water pipeline of the second circulation pump group to replenish water to the heat dissipation cooling water pipeline.

[0051] Specifically, the gas generator set 4 can be provided with a high-level water tank 5 to replenish water in the circulation system, and the second circulation pump set (one for use and one for backup) circulates the system water circuit to circulate the circulating water in the second heat exchanger 15 to heat the buried pipe 9.

[0052] In the above embodiment, preferably, a vaporization stop valve 7 is provided at the input end of the vaporizer 8 , and the vaporization stop valve 7 can be used to close the delivery of the sub-high pressure natural gas to the vaporizer 8 .

[0053] The utility model also proposes a natural gas decompression power generation and clean energy cascade heating gas method, which is applied to the natural gas decompression power generation and clean energy cascade heating gas system disclosed in any one of the above embodiments, including:

[0054] The sub-high pressure natural gas is fed into the first heat exchanger 2 through the natural gas inlet valve 1 for heat exchange, thereby increasing the temperature of the sub-high pressure natural gas;

[0055] The sub-high-pressure natural gas after heat exchange is input into the gas generator set 4 through the regulating valve set 3 to reduce the pressure and generate electricity;

[0056] The low-temperature natural gas after decompression and power generation is input into the vaporizer 8 for heating and supplementary heat;

[0057] The natural gas after the primary heating is input into the second heat exchanger 15 of the shallow geothermal energy system for secondary heating and heat exchange, and the heat of the underground soil is extracted into the second heat exchanger 15 through the buried pipe 9;

[0058] The natural gas after the second heating is fed back to the first heat exchanger 2 for heat exchange and then output to the secondary high pressure pipeline network.

[0059] In the above embodiment, preferably, the natural gas decompression power generation and clean energy cascade heating gas method also includes:

[0060] When the ambient temperature is higher than the preset temperature, the fresh air unit 19 is used to release the cold in the underground pipe 9 into the atmosphere, and the heat in the outdoor environment is added to the underground pipe 9;

[0061] Driven by the second circulation pump group, the cooling water of the gas generator set 4 is circulated and transported to the second heat exchanger 15 through the heat dissipation cooling water pipeline to transfer the working heat of the gas generator set 4 to the shallow geothermal energy system.

[0062] In the above-mentioned embodiment, the natural gas pressure-reduced power generation and clean energy cascade heating gas method are implemented based on the various components of the natural gas pressure-reduced power generation and clean energy cascade heating gas system disclosed in the above-mentioned embodiment. During the implementation process, the operation is performed with reference to the above-mentioned embodiment, which will not be repeated here.

[0063] According to the natural gas pressure-reducing power generation and clean energy cascade heating gas system and method disclosed in the above-mentioned embodiment, during the implementation process, the effects of the system and method are explained with reference to the following examples.

[0064] Embodiment 1:

[0065] The temperature of the incoming sub-high-pressure natural gas is about 11°C. After entering the first heat exchanger 2 and exchanging heat with the heated natural gas, the temperature before the regulating valve group is about 8°C. After entering the generator set for decompression and power generation, the temperature of the decompressed natural gas is about -53°C. After the vaporizer 8 uses the heat in the atmospheric environment to supplement the natural gas, the temperature rises to -20°C, which fails to meet the required temperature for access to the sub-high-pressure pipeline network. In order to make the natural gas reach the required temperature for use, it can be supplemented by the shallow geothermal energy system, and the natural gas temperature is raised to -2°C. At this time, it is circulated and exchanged with the incoming sub-high-pressure gas through the first heat exchanger 2, which can raise the natural gas temperature to above 0°C and then output to the sub-high-pressure pipeline network.

[0066] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A natural gas pressure-reducing power generation and clean energy cascade heating gas system, characterized in that: It includes a first heat exchanger, a gas generator set, a vaporizer and a shallow geothermal energy system which are sequentially connected through a loop pipeline; The shallow geothermal energy system comprises a buried pipe and a second heat exchanger, wherein the buried pipe is buried underground, and the buried pipe and the second heat exchanger form a circulation pipeline to extract heat from underground soil into the second heat exchanger; After the sub-high-pressure natural gas is input into the first heat exchanger for heat exchange, it can be output to the gas generator set for reduced-pressure power generation. The vaporizer can heat up the reduced-pressure natural gas once, and the second heat exchanger can heat-exchange and heat-increase the natural gas after the first heating. The natural gas after heat exchange and temperature increase can enter the first heat exchanger for another heat exchange and then be output.

2. The natural gas pressure reduction power generation and clean energy cascade heating gas system according to claim 1 is characterized in that: The shallow geothermal energy system also includes a water replenishment component and a first circulation pump group; The water replenishment assembly includes a water softener and a water replenishment tank, the input end of the water softener is connected to the tap water network, the output end of the water softener is connected to the input end of the water replenishment tank, and the output end of the water replenishment tank is connected to the circulation pipeline to replenish water to the circulation pipeline; The first circulation pump group is arranged on the circulation pipeline, and the first circulation pump group drives the buried pipe and the second heat exchanger to realize geothermal water circulation.

3. The natural gas pressure reduction power generation and clean energy cascade heating gas system according to claim 2 is characterized in that: The shallow geothermal energy system further comprises a valve assembly, wherein the valve assembly comprises a first stop valve, a first bypass valve and / or a second bypass valve; The first stop valve is arranged on the circulation pipeline, and the water circulation heat exchange of the shallow geothermal energy system can be closed by the first stop valve; The first bypass valve is arranged in parallel on the circulation pipeline outside the second heat exchanger, and the geothermal water is circulated through the first bypass valve instead of being heat exchanged through the second heat exchanger by switching the first bypass valve. The second bypass valve is arranged in parallel on the loop pipeline outside the second heat exchanger. By switching the second bypass valve, the natural gas circulates through the second bypass valve instead of passing through the second heat exchanger for heat exchange.

4. The natural gas pressure-reducing power generation and clean energy cascade heating gas system according to claim 3 is characterized in that: The shallow geothermal energy system also includes a fresh air unit, which is arranged in parallel with the circulation pipeline. The fresh air unit can release the cold energy in the buried pipes into the atmospheric environment and replenish the heat in the outdoor environment into the buried pipes.

5. The natural gas pressure-reducing power generation and clean energy cascade heating gas system according to claim 4 is characterized in that: The shallow geothermal energy system also includes a second stop valve, which is arranged on the input and output pipelines of the fresh air unit. The heat interaction between the fresh air unit and the buried pipe can be closed by the second stop valve.

6. The natural gas pressure-reducing power generation and clean energy cascade heating gas system according to claim 5 is characterized in that: The gas generator set includes a heat dissipation cooling water pipeline, and a third heat exchanger is arranged on the circulation pipeline. The heat dissipation cooling water pipeline is connected to the third heat exchanger through a second circulation pump group. The second circulation pump group circulates the cooling water of the gas generator set to the third heat exchanger to transfer the working heat of the gas generator set to the shallow geothermal energy system.

7. The natural gas pressure-reducing power generation and clean energy cascade heating gas system according to claim 6 is characterized in that: The gas generator set also includes a high-level water tank, the input end of which is connected to the tap water network, and the output end of which is connected to the cooling water pipeline of the second circulating pump group to replenish water to the heat dissipation cooling water pipeline.

8. The natural gas pressure-reducing power generation and clean energy cascade heating gas system according to claim 7 is characterized in that: The input end of the vaporizer is provided with a vaporization stop valve, through which the delivery of the sub-high pressure natural gas to the vaporizer can be closed.

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