Gas-fired power plant and coal-fired power plant coupled natural gas conveying system

Abstract

The utility model relates to the technical field of natural gas conveying, and discloses a gas power plant and coal-fired power plant coupled natural gas conveying system which comprises a gas inlet pipe, a flow meter, a cyclone separator, a fine filter, a connecting pipe, a first switch valve, a first pressure adjusting assembly, a second switch valve and a second pressure adjusting assembly. The air inlet pipe is sequentially connected with the flowmeter, the cyclone separator, the fine filter and the connecting pipe, the connecting pipe is connected with an air inlet of the first switch valve and an air inlet of the second switch valve, and an air outlet of the first switch valve is connected with the input end of the first pressure adjusting assembly. The output end of the first pressure regulating assembly is connected with a gas inlet of the gas unit through a first gas outlet pipe, a gas outlet of the second switch valve is connected with the input end of the second pressure regulating assembly, and the output end of the second pressure regulating assembly is connected with a boiler ignition system of the coal-fired unit through a second gas outlet pipe. The natural gas conveying device not only can convey natural gas to a gas turbine, but also can convey natural gas to a boiler ignition system of a coal-fired unit.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas transportation, in particular to a natural gas transportation system coupled with a gas-fired power plant and a coal-fired power plant. Background Art

[0002] The boiler ignition system is an important auxiliary system of coal-fired power plants. It not only affects the investment in power plant construction and the subsequent operating costs, but also directly affects the safe and stable operation of the unit. Conventional coal-fired units use an ignition oil gun solution, which consumes a lot of oil. The plant needs to set up an oil tank area, a fuel pump room and a fuel system. The related structures are fireproof and explosion-proof areas, occupying a large area and complex maintenance. In addition, with the rise in fuel prices, this solution has high operating costs and has been gradually eliminated.

[0003] Therefore, in recent years, many coal-fired power plants have adopted micro-oil ignition, plasma ignition technology and natural gas ignition. However, micro-oil ignition and plasma ignition can only ignite a small amount of coal powder in the burner at the beginning of ignition. Most of the coal powder is sent into the furnace before it can be ignited. During the ignition period, the furnace temperature is low, and the heat generated by the ignited coal powder is less than the heat absorbed by the water-cooled wall. The combustion cannot be maintained, and a part of the coal powder leaves the furnace before it is burned out. There is a problem of high carbon content in fly ash at the beginning of ignition. If natural gas ignition is used, it is necessary to set up a corresponding natural gas pipeline network. If a natural gas pipeline is required for ignition, it needs to be planned, approved and constructed by the relevant departments, and the construction period and construction cost are uncontrollable. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a natural gas transmission system for a gas-fired power plant and a coupled coal-fired power plant, which can transmit natural gas to a gas turbine and a boiler ignition system of a coal-fired unit.

[0005] In order to solve the above technical problems, the utility model provides a natural gas transmission system coupled with a gas-fired power plant and a coal-fired power plant, comprising an air inlet pipe, a flow meter, a cyclone separator, a fine filter, a connecting pipe, a first switch valve, a first pressure regulating assembly, a second switch valve, a second pressure regulating assembly, a first air outlet pipe and a second air outlet pipe, the air inlet pipe is connected to the flow meter, the cyclone separator, the fine filter and the connecting pipe in sequence, the connecting pipe is respectively connected to the air inlet of the first switch valve and the air inlet of the second switch valve, the air outlet of the first switch valve is connected to the input end of the first pressure regulating assembly, the output end of the first pressure regulating assembly is connected to the air inlet of the gas unit through the first air outlet pipe, the air outlet of the second switch valve is connected to the input end of the second pressure regulating assembly, and the output end of the second pressure regulating assembly is connected to the boiler ignition system of the coal-fired unit through the second air outlet pipe.

[0006] As a preferred embodiment of the present invention, the first pressure regulating assembly includes a first monitoring pressure regulator and a first working pressure regulator connected in sequence, the air outlet of the first switching valve is connected to the air inlet of the first monitoring pressure regulator, the air outlet of the first monitoring pressure regulator is connected to the air inlet of the first working pressure regulator, and the air outlet of the first working pressure regulator is connected to the first air outlet pipe, and the second pressure regulating assembly includes a second monitoring pressure regulator and a second working pressure regulator connected in sequence, the air outlet of the second switching valve is connected to the air inlet of the second monitoring pressure regulator, the air outlet of the second monitoring pressure regulator is connected to the air inlet of the second working pressure regulator, and the air outlet of the second working pressure regulator is connected to the second air outlet pipe.

[0007] As a preferred embodiment of the present invention, the second pressure regulating assembly also includes a first electric heater, the air outlet of the second switch valve is connected to the air inlet of the first electric heater, and the air outlet of the first electric heater is connected to the air inlet of the second monitoring voltage regulator.

[0008] As a preferred embodiment of the present utility model, a first valve is respectively provided at the air inlet and the air outlet of the flow meter, and a first bypass valve is connected in parallel to the flow meter; a second valve is respectively provided at the air inlet and the air outlet of the cyclone separator, and a second bypass valve is connected in parallel to the cyclone separator; two fine filters are provided, and the two fine filters are arranged in parallel; and a third valve is respectively provided at the air inlet and the air outlet of the fine filter.

[0009] As a preferred embodiment of the utility model, the system also includes a second electric heater, the fine filter is connected to the air inlet of the second electric heater, the air outlet of the second electric heater is connected to the connecting pipe, a fourth valve is provided at the air inlet and the air outlet of the second electric heater, and the second electric heater is connected in parallel with a third bypass valve.

[0010] As a preferred solution of the utility model, the system further comprises a waste liquid collection box, and the liquid discharge port of the cyclone separator and the liquid discharge port of the fine filter are respectively connected to the waste liquid collection box.

[0011] As a preferred embodiment of the utility model, the system also includes a natural gas discharge tower, the air inlet pipe, the connecting pipe between the flow meter and the cyclone separator, the discharge port of the cyclone separator, the discharge port of the fine filter and the connecting pipe are respectively connected to the natural gas discharge tower through a discharge pipe, and a valve is provided on the discharge pipe.

[0012] As a preferred solution of the utility model, a chromatographic analyzer is provided on the air inlet pipe.

[0013] The utility model embodiment is a natural gas transmission system coupled with a gas-fired power plant and a coal-fired power plant. Compared with the prior art, its beneficial effects are as follows: in this embodiment, when it is not necessary to supply gas to the boiler ignition system of the coal-fired unit, the natural gas passes through the meter, the cyclone separator and the fine filter in sequence, and is then transmitted to the first pressure regulating component through the connecting pipe, and is reduced in pressure by the first pressure regulating component and then transmitted to the boiler ignition system of the coal-fired unit through the first gas outlet pipeline for ignition of the coal-fired unit; when it is necessary to supply gas to the boiler ignition system of the coal-fired unit, the natural gas in the connecting pipe is diverted to the second pressure regulating component, and this part of the natural gas is reduced in pressure by the second pressure regulating component and then transmitted to the boiler ignition system of the coal-fired unit through the second gas outlet pipeline for ignition of the coal-fired unit; that is, the system can transmit natural gas to both the gas turbine and the boiler ignition system of the coal-fired unit, so as to realize the ignition of the coal-fired unit using natural gas, and the coal-fired unit and the gas-fired unit share a natural gas transmission system, which fully reflects the advantages of coupling and complementarity between the gas-fired power plant and the coal-fired power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] In the figure, 1, air inlet pipe; 11, chromatograph; 2, flow meter; 21, first valve; 22, first bypass valve; 3, cyclone separator; 31, second valve; 32, second bypass valve; 4, fine filter; 41, third valve; 42, waste liquid collection box; 5, connecting pipe; 51, first switch valve; 52, second switch valve; 6, first pressure regulating assembly; 61, first air outlet pipe; 62, first monitoring pressure regulator; 63, first working pressure regulator; 7, second pressure regulating assembly; 71, second air outlet pipe; 72, second monitoring pressure regulator; 73, second working pressure regulator; 74, first electric heater; 8, second electric heater; 81, fourth valve; 82, third bypass valve; 9, natural gas venting tower; 91, venting pipe. DETAILED DESCRIPTION

[0016] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0017] like Figure 1As shown, a natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant in a preferred embodiment of the utility model comprises an air inlet pipe 1, a flow meter 2, a cyclone separator 3, a fine filter 4, a connecting pipe 5, a first pressure regulating assembly 6, a second pressure regulating assembly 7, a first air outlet pipe 61 and a second air outlet pipe 71. The air inlet pipe 1 is connected to the flow meter 2, the cyclone separator 3, the fine filter 4 and the connecting pipe 5 in sequence. Specifically, the air inlet pipe 1 is connected to the air inlet of the flow meter 2, the air outlet of the flow meter 2 is connected to the air inlet of the cyclone separator 3, and the air outlet of the cyclone separator 3 is connected to the air outlet of the cyclone separator 3. The air outlet of the fine filter 4 is connected to the connecting pipe 5, the connecting pipe 5 is respectively connected to the air inlet of the first switch valve 51 and the air inlet of the second switch valve 52, the air outlet of the first switch valve 51 is connected to the input end of the first pressure regulating assembly 6, the output end of the first pressure regulating assembly 6 is connected to the air inlet of the gas unit through the first outlet pipe 61, the air outlet of the second switch valve 52 is connected to the input end of the second pressure regulating assembly 7, and the output end of the second pressure regulating assembly 7 is connected to the boiler ignition system of the coal-fired unit through the second outlet pipe 71.

[0018] The working process of this embodiment is as follows: when there is no need to supply gas to the boiler ignition system of the coal-fired unit, the first switch valve 51 is in an open state and the second switch valve 52 is in a closed state. At this time, the natural gas is first transported to the flow meter 2 through the air inlet pipe 1 to measure the natural gas; then the natural gas is transported to the cyclone separator 3 to separate the natural gas into gas and solid or gas and liquid; then the natural gas is transported to the fine filter 4, which is a key device for removing tiny particles and impurities in the natural gas to ensure that the transported natural gas reaches the required purity; thereafter, the natural gas is transported to the first pressure regulating component 6 through the connecting pipe 5, and the natural gas after the pressure reduction treatment by the first pressure regulating component 6 is passed through the cyclone separator 3 to separate the natural gas into gas and solid or gas and liquid. It is transported to the gas unit through the first air outlet pipe 61 for combustion and power generation by the gas unit; thereafter, when it is necessary to supply gas to the boiler ignition system of the coal-fired unit, the second switch valve 52 is opened, and the natural gas in the connecting pipe 5 is diverted to the second pressure regulating component 7. This part of the natural gas is reduced in pressure by the second pressure regulating component 7 and then transported to the boiler ignition system of the coal-fired unit through the second air outlet pipe 71 for ignition of the coal-fired unit. It can be understood that since the amount of natural gas used for ignition of the coal-fired unit is much less than the gas consumption of the gas unit, it will basically not affect the operation of the gas unit at this time. When the coal-fired unit is ignited, the second switch valve 52 can be closed.

[0019] In this embodiment, when it is not necessary to supply gas to the boiler ignition system of the coal-fired unit, the natural gas passes through the meter, the cyclone separator 3 and the fine filter 4 in sequence, and is transported to the first pressure regulating component 6 through the connecting pipe 5. After being reduced in pressure by the first pressure regulating component 6, it is transported to the boiler ignition system of the coal-fired unit through the first outlet pipe 61 for ignition of the coal-fired unit; when it is necessary to supply gas to the boiler ignition system of the coal-fired unit, the natural gas in the connecting pipe 5 is diverted to the second pressure regulating component 7. After being reduced in pressure by the second pressure regulating component 7, this part of the natural gas is transported to the boiler ignition system of the coal-fired unit through the second outlet pipe 71 for ignition of the coal-fired unit; that is, this system can both transport natural gas to the gas turbine , and can deliver natural gas to the boiler ignition system of the coal-fired unit. Coal-fired power plants and gas-fired power plants share a natural gas delivery system, which saves space in the oil tank area and fuel pump room, reduces the maintenance of the complex fuel system, is operator-friendly, simple to maintain, and requires low initial investment, fully reflecting the advantages of the coupled and complementary thermal systems of gas-fired power plants and coal-fired power plants; coal-fired units use low-cost natural gas instead of fuel ignition to reduce the operating costs of power plants and improve economic benefits. Natural gas ignition can avoid the restrictions of conventional ignition methods on coal quality, has a wide range of applications, is safe and reliable, and the combustion products of natural gas are carbon dioxide and water, which avoids the emission of carbon-containing fly ash in conventional ignition schemes, which is in line with the emission reduction policies promoted by the country.

[0020] Exemplarily, the first pressure regulating assembly 6 includes a first monitoring pressure regulator 62 and a first working pressure regulator 63 connected in sequence, the air outlet of the first switching valve 51 is connected to the air inlet of the first monitoring pressure regulator 62, the air outlet of the first monitoring pressure regulator 62 is connected to the air inlet of the first working pressure regulator 63, and the air outlet of the first working pressure regulator 63 is connected to the first air outlet pipe 61; the second pressure regulating assembly 7 includes a second monitoring pressure regulator 72 and a second working pressure regulator 73 connected in sequence, the air outlet of the second switching valve 52 is connected to the air inlet of the second monitoring pressure regulator 72, the air outlet of the second monitoring pressure regulator 72 is connected to the air inlet of the second working pressure regulator 73, and the air outlet of the second working pressure regulator 73 is connected to the second air outlet pipe 71; the monitoring pressure regulator and the working pressure regulator are used in series to form a dual protection mechanism, which can automatically intervene and maintain the stability of the outlet pressure when the working pressure regulator fails or the outlet pressure exceeds the set pressure, thereby ensuring the safety and continuous gas supply of the system.

[0021] Exemplarily, the second pressure regulating component 7 also includes a first electric heater 74, the air outlet of the second switch valve 52 is connected to the air inlet of the first electric heater 74, and the air outlet of the first electric heater 74 is connected to the air inlet of the second monitoring pressure regulator 72. The natural gas output from the air outlet of the second switch valve 52 is first heated by the first electric heater, and then transported to the second monitoring pressure regulator 72 and the second working pressure regulator 73 for pressure regulation to prevent the natural gas from being blocked by ice due to its temperature being too low.

[0022] Exemplarily, the air inlet and the air outlet of the flow meter 2 are respectively provided with a first valve 21, and the flow meter 2 is connected in parallel with a first bypass valve 22. By closing the two first valves 21 and opening the first bypass valve 22, the flow meter 2 can be repaired or replaced without stopping the system. The air inlet and the air outlet of the cyclone separator 3 are respectively provided with a second valve 31, and the cyclone separator 3 is connected in parallel with a second bypass valve 32. By closing the two second valves 31 and opening the second bypass valve 32, the cyclone separator 3 can be repaired or replaced without stopping the system. For maintenance or replacement, two fine filters 4 are arranged in parallel, and third valves 41 are respectively provided at the air inlet and the air outlet of the fine filter 4. Under normal circumstances, only one of the fine filters 4 is working, and the other fine filter 4 is in a standby state, that is, the third valves 41 at the air inlet and the air outlet of one fine filter 4 are opened, and the third valves 41 at the air inlet and the air outlet of the other fine filter 4 are closed. At this time, the fine filter 4 that is not working can be repaired or replaced without stopping the system.

[0023] Exemplarily, the system also includes a second electric heater 8, the fine filter 4 is connected to the air inlet of the second electric heater 8, the air outlet of the second electric heater 8 is connected to the connecting pipe 5, and a fourth valve 81 is provided at the air inlet and the air outlet of the second electric heater 8. The second electric heater 8 is connected in parallel with a third bypass valve 82. When the two fourth valves 81 are opened and the third bypass valve 82 is closed, the natural gas filtered by the fine filter 4 is transported to the second electric heater 8. After being heated by the second electric heater 8, the natural gas is transported to the first pressure regulating component 6 and the second pressure regulating component 7 through the connecting pipe 5 for pressure reduction treatment to prevent ice blockage caused by excessively low temperature of the natural gas.

[0024] Exemplarily, the system further comprises a waste liquid collection box 42, and the discharge port of the cyclone separator 3 and the discharge port of the fine filter 4 are respectively connected to the waste liquid collection box 42, so as to collect the waste liquid in a unified manner.

[0025] Exemplarily, the system also includes a natural gas release tower 9, the air inlet pipe 1, the connecting pipe 5 between the flow meter 2 and the cyclone separator 3, the release port of the cyclone separator 3, the release port of the fine filter 4 and the connecting pipe 5 are respectively connected to the natural gas release tower 9 through a release pipe 91, and a control valve is provided on the release pipe 91, or a parallel control valve and a safety valve are provided on the release pipe 91. In the case of pipeline or equipment maintenance, overpressure protection, emergency accident handling, etc., the natural gas in the pipeline or equipment can be discharged to the release tower through the release pipe 91 for storage to ensure the safety of the system; generally, the connecting pipe 5 between the flow meter 2 and the cyclone separator 3 and the release connected to the connecting pipe 5 only need to be provided with a control valve (such as a stop valve), while the release pipe 91 connected to the release port of the cyclone separator 3 and the release port of the fine filter 4 needs to be provided with a parallel control valve and a safety valve (such as a pressure relief valve).

[0026] Exemplarily, a chromatographic analyzer 11 is provided on the air inlet pipe 1, and various components in the natural gas can be measured by the chromatographic analyzer 11.

[0027] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant, characterized in that: It includes an air inlet pipe, a flow meter, a cyclone separator, a fine filter, a connecting pipe, a first switch valve, a first pressure regulating assembly, a second switch valve, a second pressure regulating assembly, a first air outlet pipe and a second air outlet pipe, the air inlet pipe is connected to the flow meter, the cyclone separator, the fine filter and the connecting pipe in sequence, the connecting pipe is respectively connected to the air inlet of the first switch valve and the air inlet of the second switch valve, the air outlet of the first switch valve is connected to the input end of the first pressure regulating assembly, the output end of the first pressure regulating assembly is connected to the air inlet of the gas unit through the first air outlet pipe, the air outlet of the second switch valve is connected to the input end of the second pressure regulating assembly, and the output end of the second pressure regulating assembly is connected to the boiler ignition system of the coal-fired unit through the second air outlet pipe.

2. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: The first pressure regulating assembly includes a first monitoring pressure regulator and a first working pressure regulator connected in sequence, the air outlet of the first switching valve is connected to the air inlet of the first monitoring pressure regulator, the air outlet of the first monitoring pressure regulator is connected to the air inlet of the first working pressure regulator, and the air outlet of the first working pressure regulator is connected to the first air outlet pipe, and the second pressure regulating assembly includes a second monitoring pressure regulator and a second working pressure regulator connected in sequence, the air outlet of the second switching valve is connected to the air inlet of the second monitoring pressure regulator, the air outlet of the second monitoring pressure regulator is connected to the air inlet of the second working pressure regulator, and the air outlet of the second working pressure regulator is connected to the second air outlet pipe.

3. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 2 is characterized by: The second pressure regulating component also includes a first electric heater, the air outlet of the second switch valve is connected to the air inlet of the first electric heater, and the air outlet of the first electric heater is connected to the air inlet of the second monitoring voltage regulator.

4. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: The flow meter is provided with a first valve at the air inlet and the air outlet respectively, and the flow meter is connected with a first bypass valve in parallel. The cyclone separator is provided with a second valve at the air inlet and the air outlet respectively, and the cyclone separator is connected with a second bypass valve in parallel. Two fine filters are provided, and the two fine filters are arranged in parallel. The air inlet and the air outlet of the fine filter are provided with a third valve respectively.

5. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: It also includes a second electric heater, the fine filter is connected to the air inlet of the second electric heater, the air outlet of the second electric heater is connected to the connecting pipe, a fourth valve is provided at the air inlet and the air outlet of the second electric heater, and the second electric heater is connected in parallel with a third bypass valve.

6. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: It also includes a waste liquid collection box, and the discharge port of the cyclone separator and the discharge port of the fine filter are respectively connected to the waste liquid collection box.

7. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: It also includes a natural gas discharge tower. The air inlet pipe, the connecting pipe between the flow meter and the cyclone separator, the discharge port of the cyclone separator, the discharge port of the fine filter and the connecting pipe are respectively connected to the natural gas discharge tower through discharge pipes. A control valve is provided on the discharge pipe, or a parallel control valve and a safety valve are provided on the discharge pipe.

8. The natural gas transmission system for coupling a gas-fired power plant and a coal-fired power plant according to claim 1, characterized in that: The air inlet pipe is provided with a chromatographic analyzer.

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