CN214887268U - Gas-steam combined cycle unit capable of preventing natural gas leakage - Google Patents
Gas-steam combined cycle unit capable of preventing natural gas leakage Download PDFInfo
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- CN214887268U CN214887268U CN202120539698.XU CN202120539698U CN214887268U CN 214887268 U CN214887268 U CN 214887268U CN 202120539698 U CN202120539698 U CN 202120539698U CN 214887268 U CN214887268 U CN 214887268U
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 298
- 239000003345 natural gas Substances 0.000 title claims abstract description 149
- 239000007789 gas Substances 0.000 claims abstract description 98
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 61
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- 238000002485 combustion reaction Methods 0.000 claims description 11
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Abstract
The embodiment of the utility model provides a gas-steam combined cycle unit capable of preventing natural gas leakage, wherein a joint of a gas turbine and a housing of the gas turbine are welded into a whole by adopting high pressure; one end of the natural gas conveying pipeline is communicated with the fuel inlet end of the FGH system; the fuel outlet end of the FGH system is communicated with the natural gas inlet end of the gas turbine through a high-pressure steel pipe; the natural gas bypass pipeline is connected with the natural gas supercharger in parallel; a flap check valve and a pneumatic quick opening and closing valve are sequentially arranged on the natural gas bypass pipeline along the natural gas conveying direction; the air source supply system is communicated with the pneumatic quick opening and closing valve and supplies a driving air source required by the opening and closing action to the pneumatic quick opening and closing valve; an opening and closing control valve is arranged between the air source supply system and the pneumatic quick opening and closing valve; the water inlet end of the FGH system is communicated with the water outlet end of the medium-pressure economizer. The problem of natural gas leakage in the housing of the gas turbine is solved by adopting a high-pressure welding technology, and the safe operation reliability of the housing of the gas turbine is improved.
Description
Technical Field
The utility model relates to a gas-steam combined cycle unit technical field particularly, relates to a can prevent gas-steam combined cycle unit of natural gas leakage.
Background
The electric energy is a clean secondary energy, and is convenient to transport and distribute, easy to convert into other energy sources, convenient to control, manage and dispatch and easy to realize automation, so the electric energy is widely applied to various aspects of national economy, social production and people's life. Most of electric energy is provided by power plants in an electric power system, and the electric power industry has become the basis for realizing modernization in China and is developed rapidly. The power generation is carried out by adopting the gas-steam combined cycle technology, so that the power generation efficiency is high, and the pollution to the environment can be greatly reduced by adopting the natural gas power generation, therefore, the power generation by adopting the gas-steam combined cycle technology gradually becomes the dominant force of the power development in China.
However, in the gas-steam combined cycle power plant, on the one hand, in order to make the pressure of the natural gas supplied by the upstream gas group meet the use requirement of the combustion engine, a natural gas booster is correspondingly arranged in the power plant, but if the booster fails, the supply of the natural gas required by the combustion engine is interrupted, so that the combustion engine cannot normally operate to generate power, and the safety and reliability of the natural gas system cannot be guaranteed. On the other hand, the gas turbine unit has the problem of natural gas leakage of a cover instrument connector for a long time, the cover of the gas turbine is a region which strictly forbids a fire source and ignition objects, the internal temperature of the cover is high, the local high temperature is usually over 80 ℃, if the natural gas leakage occurs, the cover is easily ignited, even the explosion is caused in serious conditions, and great hidden dangers exist for the power production and equipment safety of the gas turbine unit. Meanwhile, the problem of concealment often exists in the leakage of the instrument joint in the housing, namely, a handheld leak detector is used for detecting, micro-leakage points can be frequently leaked, the discovery time has delay, the housing has the position of micro-leakage for a long time, and great hidden danger exists for the safety of the housing.
Disclosure of Invention
The present specification provides a gas-steam combined cycle plant that prevents natural gas leakage to overcome at least one technical problem in the prior art.
According to the embodiment of the specification, a gas-steam combined cycle unit capable of preventing natural gas leakage is provided, and comprises a boiler system, a gas turbine system, a steam turbine system and a condenser system;
the boiler system comprises two waste heat boilers, two low-pressure steam drums, two medium-pressure steam drums, two high-pressure steam drums, two medium-pressure water feeding pumps, two high-pressure water feeding pumps, and a low-pressure economizer, a low-pressure evaporator, a low-pressure superheater, a medium-pressure economizer, a medium-pressure evaporator, a medium-pressure superheater, a reheater, a high-pressure economizer, a high-pressure evaporator and a high-pressure superheater which are arranged in each waste heat boiler; the two waste heat boilers are respectively in one-to-one correspondence with the two low-pressure steam drums, the two medium-pressure steam drums, the two high-pressure steam drums, the two medium-pressure water feeding pumps and the two high-pressure water feeding pumps; the water outlet end of the low-pressure economizer is communicated with the low-pressure steam drum; two ends of the low-pressure evaporator are respectively communicated with the low-pressure steam pocket; the steam inlet end of the low-pressure superheater is communicated with the low-pressure steam drum; the steam outlet end of the low-pressure superheater is connected with a low-pressure steam conveying pipeline; a low-pressure steam combining valve is arranged on the low-pressure steam conveying pipeline; the water inlet end of the medium-pressure economizer is communicated with the low-pressure steam pocket through the medium-pressure water feed pump; the water outlet end of the medium-pressure economizer is communicated with the medium-pressure steam drum; two ends of the medium-pressure evaporator are respectively communicated with the medium-pressure steam pocket; the steam inlet end of the intermediate-pressure superheater is communicated with the intermediate-pressure steam drum; the steam outlet end of the intermediate-pressure superheater is communicated with the steam inlet end of the reheater through an intermediate-pressure superheated steam conveying pipeline; the steam outlet end of the reheater is connected with a reheat steam conveying pipeline; a medium-pressure parallel valve is arranged on the reheating steam conveying pipeline; the water inlet end of the high-pressure economizer is communicated with the high-pressure steam pocket through the high-pressure water feed pump; the water outlet end of the high-pressure economizer is communicated with the high-pressure steam drum; two ends of the high-pressure evaporator are respectively communicated with the high-pressure steam pocket; the steam inlet end of the high-pressure superheater is communicated with the high-pressure steam drum; the steam outlet end of the high-pressure superheater is connected with a high-pressure steam conveying pipeline; a high-pressure steam combining valve is arranged on the high-pressure steam conveying pipeline;
the gas turbine system comprises two gas turbines, a natural gas conveying pipeline, a natural gas supercharger, a pneumatic control valve, a natural gas bypass pipeline, a pneumatic quick start and stop valve, a gas source supply system, a flap type check valve, a start and stop control valve, a controller, an FGH system and a first check valve; the two gas turbines correspond to the two waste heat boilers one by one; the gas inlet end of each waste heat boiler is communicated with one gas turbine; the joint of the gas turbine and the housing of the gas turbine are welded into a whole by adopting high pressure welding; one end of the natural gas conveying pipeline is communicated with a natural gas source, and the other end of the natural gas conveying pipeline is communicated with a fuel gas inlet end of the FGH system; the fuel outlet end of the FGH system is communicated with the natural gas inlet end of the gas turbine through a high-pressure steel pipe; the natural gas transmission pipeline is provided with the natural gas supercharger; the pneumatic control valve is installed on the natural gas conveying pipeline between the FGH system and the natural gas booster; the natural gas bypass pipeline is connected with the natural gas booster in parallel; the natural gas bypass pipeline is sequentially provided with the flap type check valve and the pneumatic quick opening and closing valve along the natural gas conveying direction; the air source supply system is communicated with the pneumatic quick opening and closing valve and supplies a driving air source required by the opening and closing action to the pneumatic quick opening and closing valve; the opening and closing control valve is arranged between the air source supply system and the pneumatic quick opening and closing valve; the water inlet end of the FGH system is communicated with the water outlet end of the medium-pressure economizer; the water outlet end of the FGH system is communicated with the water inlet end of the low-pressure economizer through the first check valve; the natural gas booster is electrically connected with the controller; the control end of the pneumatic quick opening and closing valve is electrically connected with the controller;
the steam turbine system comprises a high-pressure steam turbine, a medium-pressure steam turbine, a low-pressure steam turbine, a communicating pipe, a high-pressure steam exhaust main pipeline and a high-pressure steam exhaust branch pipeline which are coaxially connected; the steam outlet end of the medium-pressure turbine is communicated with the steam inlet end of the low-pressure turbine through the communicating pipe; the two low-pressure steam delivery pipelines are converged and then are connected to the communicating pipe together; the two reheat steam delivery pipelines are converged and then are connected to the steam inlet end of the medium-pressure steam turbine together; the two high-pressure steam conveying pipelines are converged and then are connected to the steam inlet end of the high-pressure turbine together; the steam outlet end of the high-pressure steam turbine is connected with the high-pressure steam exhaust main pipeline; two paths of high-pressure steam exhaust branch pipelines are led out from the high-pressure steam exhaust main pipeline; the two high-pressure steam exhaust branch pipelines are respectively communicated with the two medium-pressure superheated steam conveying pipelines;
the condenser system comprises a condenser and a condensate pump; and the water outlet end of the condenser is respectively communicated with the water inlet ends of the two low-pressure coal economizers through the condensate pump.
Optionally, the reheater comprises a primary reheater and a secondary reheater; the steam inlet end of the primary reheater is connected with the medium-pressure superheated steam conveying pipeline; the steam outlet end of the primary reheater is communicated with the steam inlet end of the secondary reheater; and the steam outlet end of the secondary reheater is connected with the reheat steam conveying pipeline.
Optionally, the second check valve is mounted on the medium-pressure superheated steam delivery pipe.
Optionally, the third check valve is installed on the high-pressure exhaust branch pipe.
Optionally, a high-pressure bypass pressure regulating valve is arranged between the high-pressure steam delivery pipeline and the high-pressure steam exhaust branch pipeline.
Optionally, a low-pressure bypass connected with the condenser is led out from the low-pressure steam conveying pipeline, and a low-pressure bypass pressure regulating valve is installed on the low-pressure bypass.
Optionally, a medium-pressure bypass connected with the condenser is led out from the reheat steam conveying pipeline, and a medium-pressure bypass pressure regulating valve is installed on the medium-pressure bypass.
Optionally, the gas-steam combined cycle unit further comprises a generator system;
the generator system comprises two gas turbine generators and a steam turbine generator; each gas turbine generator is coaxially connected with one gas turbine and driven by the gas turbine to generate power; the steam turbine generator is coaxially connected with the high-pressure turbine and driven by the high-pressure turbine, the medium-pressure turbine and the low-pressure turbine to generate electricity.
Optionally, the low-pressure parallel valve, the medium-pressure parallel valve and the high-pressure parallel valve are all electrically operated valves.
Optionally, the combustion engine system further comprises an air heat exchanger; and the air inlet end of the gas turbine is connected with the air heat exchanger.
The beneficial effects of the embodiment of the specification are as follows:
the mode of connecting a bypass device in parallel at the natural gas booster compressor is adopted, and the safety and reliability of the natural gas system are improved. The quick opening and closing valve in the bypass device is opened and closed according to the real-time states of starting, stopping and the like of the natural gas supercharger, so that the investment cost of the natural gas supercharger is not increased, the natural gas of the gas turbine cannot be instantly supplied when the natural gas supercharger breaks down, the load shedding and normal stopping of the gas turbine can be guaranteed, and the non-stop of a unit is avoided. Simultaneously, still when air feed pressure can directly satisfy combustion engine user demand upstream, the natural gas booster compressor of stopping transport, through the direct supply natural gas of bypass device, avoid the natural gas to pass through the booster compressor and form the pressure drop, improved the economic benefits of power plant.
In addition, the problem of natural gas leakage in the housing of the gas turbine is solved by adopting a high-pressure welding technology, the problem of natural gas leakage of an instrument joint is fundamentally avoided, the problem that leakage points cannot be isolated during the operation of the unit is solved, important guarantee is provided for the intrinsic operation safety of the gas turbine unit, the work load is reduced for the local inspection of the natural gas leakage points, the safe operation reliability of the housing of the gas turbine is improved, and the safety of a housing natural gas system is essentially improved.
The innovation points of the embodiment of the specification comprise:
1. in this embodiment, a mode that a bypass device is connected in parallel to the natural gas supercharger is adopted, so that the safety and reliability of a natural gas system are improved, a quick opening and closing valve in the bypass device is opened and closed according to real-time states of starting, stopping and the like of the natural gas supercharger, the investment cost of the natural gas supercharger is not required to be increased, so that when the natural gas supercharger breaks down, natural gas of a gas turbine cannot be instantly supplied, the gas turbine can be guaranteed to be normally stopped and operated under load shedding, and the non-stop of a unit is avoided.
2. In this embodiment, when the upstream air supply pressure can directly satisfy the use demand of the gas turbine, the natural gas booster is stopped to be supplied directly through the bypass device, so that the natural gas is prevented from forming a pressure drop through the booster, the economic benefit of the power plant is improved, and the natural gas booster is one of the innovation points of the embodiment of the description.
3. In the embodiment, the problem of natural gas leakage in the housing of the gas turbine is solved by adopting a high-pressure welding technology, the problem of natural gas leakage of an instrument joint is fundamentally avoided, the problem that leakage points cannot be isolated during the operation of a unit is solved, important guarantee is provided for the intrinsic operation safety of the gas turbine unit, the workload is reduced for the local investigation of the natural gas leakage points, the safe operation reliability of the housing of the gas turbine is improved, and the safety of a housing natural gas system is essentially improved, so that the gas turbine housing is one of the innovation points of the embodiment of the specification.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a combined gas-steam cycle plant capable of preventing natural gas leakage according to an embodiment of the present disclosure;
in the figure, 1 is a waste heat boiler, 2 is a low-pressure steam drum, 3 is a medium-pressure steam drum, 4 is a high-pressure steam drum, 5 is a medium-pressure water-feeding pump, 6 is a high-pressure water-feeding pump, 7 is a low-pressure economizer, 8 is a low-pressure evaporator, 9 is a low-pressure superheater, 10 is a medium-pressure economizer, 11 is a medium-pressure evaporator, 12 is a medium-pressure superheater, 13 is a primary reheater, 14 is a secondary reheater, 15 is a high-pressure economizer, 16 is a high-pressure evaporator, 17 is a high-pressure superheater, 18 is a low-pressure steam delivery pipeline, 19 is a low-pressure combined throttle, 20 is a medium-pressure superheated steam delivery pipeline, 21 is a reheated steam delivery pipeline, 22 is a medium-pressure combined throttle, 23 is a high-pressure steam delivery pipeline, 24 is a high-pressure combined throttle, 25 is a gas turbine, 26 is a natural gas delivery pipeline, 27 is a natural gas control valve, 28 is a gas booster, 29 is a natural gas bypass pipeline, 30 is a gas quick-operated valve, a quick-operated valve is closed, 31 is an air source supply system, 32 is a flap check valve, 33 is an on-off control valve, 34 is an air heat exchanger, 35 is an FGH system, 36 is a first check valve, 37 is a high-pressure steel pipe, 38 is a high-pressure turbine, 39 is a medium-pressure turbine, 40 is a low-pressure turbine, 41 is a communicating pipe, 42 is a high-pressure exhaust main pipeline, 43 is a high-pressure exhaust branch pipeline, 44 is a condenser, 45 is a condensate pump, 46 is a second check valve, 47 is a third check valve, 48 is a high-pressure bypass pressure regulating valve, 49 is a low-pressure bypass, 50 is a low-pressure bypass pressure regulating valve, 51 is a medium-pressure bypass, 52 is a medium-pressure bypass pressure regulating valve, 53 is a gas turbine generator, and 54 is a steam turbine generator.
Detailed Description
The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without any creative effort belong to the protection scope of the present invention.
It should be noted that the terms "including" and "having" and any variations thereof in the embodiments of the present specification and the drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
The embodiment of the specification discloses a gas-steam combined cycle unit capable of preventing natural gas leakage. The following are detailed below.
Fig. 1 is a block diagram illustrating a gas-steam combined cycle plant capable of preventing natural gas leakage according to an embodiment of the present disclosure. As shown in fig. 1, the gas-steam combined cycle plant includes a boiler system, a combustion engine system, a steam turbine system, a condenser system, and a generator system.
The embodiment of the utility model provides a gas-steam combined cycle unit is two and drags a combustion engine combined cycle unit, it includes two exhaust-heat boiler 1, two gas turbine 25, a steam turbine, a condenser 44, two gas turbine generators 53 and a steam turbine generator 54, wherein, steam turbine comprises coaxial coupling's high pressure steam turbine 38, medium pressure steam turbine 39, low pressure steam turbine 40, can produce low simultaneously, well, high steam, drive high pressure steam turbine 38 respectively, medium pressure steam turbine 39, low pressure steam turbine 40, convert the heat energy of natural gas into mechanical work most fully, the economic benefits of power plant improves. The steam outlet end of the medium pressure turbine 39 is communicated with the steam inlet end of the low pressure turbine 40 through a communicating pipe 41, the two gas turbines 25 correspond to the two waste heat boilers 1 one by one, and the two waste heat boilers 1 correspond to the two low pressure steam drums 2, the two medium pressure steam drums 3, the two high pressure steam drums 4, the two medium pressure water feeding pumps 5 and the two high pressure water feeding pumps 6 respectively; each gas turbine generator 53 is coaxially connected with one gas turbine 25 and driven by the gas turbine 25 to generate electricity; the steam turbine generator 54 is coaxially connected with the high pressure turbine 38 and is driven by the high pressure turbine 38, the intermediate pressure turbine 39 and the low pressure turbine 40 to generate electricity; the air inlet end of each waste heat boiler 1 is respectively communicated with a gas turbine 25, the high-temperature gas discharged by the gas turbine 25 is conveyed into the waste heat boiler 1 communicated with the gas turbine, the water in the waste heat boiler 1 is heated into steam to push the steam turbine to do work, and the steam turbine generator 54 is driven to generate electricity.
The water outlet end of the condenser 44 is respectively communicated with the water inlet ends of the two low-pressure economizers 7 through a condensate pump 45, so that the condensate in the condenser 44 is conveyed to the low-pressure economizers 7 under the action of the condensate pump 45 to supply required water sources for the boiler system.
The water outlet end of the low-pressure economizer 7 is communicated with the low-pressure steam drum 2; two ends of the low-pressure evaporator 8 are respectively communicated with the low-pressure steam drum 2; the steam inlet end of the low-pressure superheater 9 is communicated with the low-pressure steam drum 2; the steam outlet end of the low-pressure superheater 9 is connected with a low-pressure steam conveying pipeline 18; a low-pressure steam delivery pipeline 18 is provided with a low-pressure steam combining valve 19, and the low-pressure steam combining valve 19 is preferably an electric valve and has strong automation; the two low-pressure steam delivery pipes 18 are joined together and then connected to the communicating pipe 41. The condensed water delivered by the condensed water pump 45 is preheated by the low-pressure economizer 7 and then input into the low-pressure steam drum 2, the low-pressure steam drum 2 is communicated with the low-pressure evaporator 8, the water is heated into saturated steam in the low-pressure evaporator 8 and rises into the low-pressure steam drum 2, the saturated steam is output from the low-pressure steam drum 2 and then heated by the low-pressure superheater 9 to generate low-pressure superheated steam, the two paths of low-pressure superheated steam are converged and then mixed with the exhaust steam of the medium-pressure steam turbine 39 and then delivered to the low-pressure steam turbine 40 together to drive the low-pressure steam turbine 40 to rotate to do work, and the steam turbine generator 54 is driven to generate electricity.
The water inlet end of the medium-pressure economizer 10 is communicated with the low-pressure steam drum 2 through a medium-pressure water feed pump 5; the water outlet end of the medium-pressure economizer 10 is communicated with the medium-pressure steam drum 3; two ends of the medium-pressure evaporator 11 are respectively communicated with the medium-pressure steam drum 3; the steam inlet end of the intermediate-pressure superheater 12 is communicated with the intermediate-pressure steam drum 3; the steam outlet end of the intermediate-pressure superheater 12 is communicated with the steam inlet end of the reheater through an intermediate-pressure superheated steam conveying pipeline 20; the steam outlet end of the reheater is connected with a reheat steam conveying pipeline 21; the reheating steam conveying pipeline 21 is provided with a medium-pressure parallel valve 22, and the medium-pressure parallel valve 22 is preferably an electric valve and has strong automation; the two reheat steam delivery pipes 21 are joined together and then connected to the steam inlet end of the intermediate pressure turbine 39. In addition, the steam outlet end of the high pressure turbine 38 is connected with a high pressure steam exhaust main 42; two high-pressure steam exhaust branch pipelines 43 are led out from the high-pressure steam exhaust main pipeline 42; the two high-pressure steam exhaust branch pipelines 43 are respectively communicated with the two medium-pressure superheated steam conveying pipelines 20. The reheater comprises a primary reheater 13 and a secondary reheater 14; the steam inlet end of the primary reheater 13 is connected with a medium-pressure superheated steam conveying pipeline 20; the steam outlet end of the primary reheater 13 is communicated with the steam inlet end of the secondary reheater 14; the steam outlet end of the secondary reheater 14 is connected to a reheat steam delivery line 21.
The water output by the low-pressure steam drum 2 is injected into the medium-pressure economizer 10 by the medium-pressure water feed pump 5 to be continuously heated, then enters the medium-pressure steam drum 3, and is heated into saturated steam in the medium-pressure evaporator 11 to rise to the medium-pressure steam drum 3. Saturated steam output from the medium-pressure steam drum 3 is heated by the medium-pressure superheater 12, then mixed with steam exhausted from a high-pressure steam exhaust end of the high-pressure steam turbine 38, and sequentially heated by the primary reheater 13 and the secondary reheater 14 to generate medium-pressure reheated steam, and the two paths of medium-pressure reheated steam are converged and then jointly transmitted to the medium-pressure steam turbine 39 to drive the medium-pressure steam turbine 39 to rotate to do work, so that the steam turbine generator 54 is driven to generate electricity.
The water inlet end of the high-pressure economizer 15 is communicated with the high-pressure steam pocket 4 through a high-pressure water feed pump 6; the water outlet end of the high-pressure economizer 15 is communicated with the high-pressure steam drum 4; two ends of the high-pressure evaporator 16 are respectively communicated with the high-pressure steam drum 4; the steam inlet end of the high-pressure superheater 17 is communicated with the high-pressure steam drum 4; the steam outlet end of the high-pressure superheater 17 is connected with a high-pressure steam conveying pipeline 23; a high-pressure parallel valve 24 is arranged on the high-pressure steam conveying pipeline 23, and the high-pressure parallel valve 24 is preferably an electric valve and has strong automation; the two high-pressure steam delivery pipes 23 are joined together and connected to the steam inlet end of a high-pressure turbine 38. Water output by the low-pressure steam pocket 2 is injected into the high-pressure economizer 15 by the high-pressure water feed pump 6 to be continuously heated, then enters the high-pressure steam pocket 4, is heated into saturated steam in the high-pressure evaporator 16 and rises to the high-pressure steam pocket 4, the saturated steam output by the high-pressure steam pocket 4 is heated by the high-pressure superheater 17 to generate high-pressure superheated steam, and the two paths of high-pressure superheated steam are converged and then jointly conveyed to the high-pressure steam turbine 38 to drive the high-pressure steam turbine 38 to rotate to do work, so that the steam turbine generator 54 is driven to generate electricity.
In addition, in order to improve the safety of the system, a second check valve 46 is installed on the medium-pressure superheated steam conveying pipeline 20, a third check valve 47 is installed on the high-pressure exhaust steam branch pipeline 43, and the second check valve 46 and the third check valve 47 are used for preventing the steam and the condensed water in the pipelines from flowing back, so that the safety of the system is ensured. Meanwhile, a high-pressure bypass pressure regulating valve 48 is arranged between the high-pressure steam conveying pipeline 23 and the high-pressure steam exhaust branch pipeline 43, and the steam in the high-pressure steam conveying pipeline 23 is conveyed to the high-pressure steam exhaust branch pipeline 43 by the high-pressure bypass pressure regulating valve 48 so as to be exhausted into the condenser 44 through a medium-pressure bypass 51; a low-pressure bypass 49 connected with the condenser 44 is led out from the low-pressure steam conveying pipeline 18, a low-pressure bypass pressure regulating valve 50 is installed on the low-pressure bypass 49, and the steam in the low-pressure steam conveying pipeline 18 is discharged into the condenser 44 through the low-pressure bypass 49 by controlling the low-pressure bypass pressure regulating valve 50; a middle-pressure bypass 51 connected with the condenser 44 is led out from the reheating steam conveying pipeline 21, a middle-pressure bypass pressure regulating valve 52 is installed on the middle-pressure bypass 51, and the steam in the reheating steam conveying pipeline 21 is discharged into the condenser 44 through the middle-pressure bypass 51 by controlling the middle-pressure bypass pressure regulating valve 52.
In order to improve the safety and reliability of the combustion engine system and avoid the non-stop of the unit when the natural gas supercharger 27 fails, a bypass device is connected in parallel with the natural gas supercharger 27 of the gas turbine 25, and the natural gas supply of the gas turbine 25 is supplemented by the bypass device. Specifically, one end of the natural gas conveying pipeline 26 is communicated with a natural gas source, and the other end is communicated with a fuel gas inlet end of the FGH system 35; the fuel outlet end of the FGH system 35 is communicated with the natural gas inlet end of the gas turbine 25 through a high-pressure steel pipe 37; a natural gas booster 27 is arranged on the natural gas conveying pipeline 26; a pneumatic control valve 28 is arranged on the natural gas conveying pipeline 26 between the FGH system 35 and the natural gas booster 27; a natural gas bypass pipeline 29 is connected in parallel with the natural gas booster 27; a flap check valve 32 and a pneumatic quick opening and closing valve 30 are sequentially arranged on the natural gas bypass pipeline 29 along the natural gas conveying direction; the air source supply system 31 is communicated with the pneumatic quick opening and closing valve 30 and supplies a driving air source required by the opening and closing action for the pneumatic quick opening and closing valve 30; an opening and closing control valve 33 is arranged between the air source supply system 31 and the pneumatic quick opening and closing valve 30; the water inlet end of the FGH system 35 is communicated with the water outlet end of the medium-pressure economizer 10; the water outlet end of the FGH system 35 is communicated with the water inlet end of the low-pressure economizer 7 through a first check valve 36, natural gas backflow is prevented by the first check valve 36, and the safety and reliability of natural gas conveying are improved; the natural gas supercharger 27 is electrically connected with the controller; the control end of the pneumatic quick opening and closing valve 30 is electrically connected with a controller; an air heat exchanger 34 is connected to an air inlet end of the gas turbine 25.
Where in this specification FGH system refers to a fuel performance heater system.
When the gas supply pressure of the upstream gas group can directly meet the use requirement of the gas turbine 25, even if the natural gas booster 27 is not used, the natural gas can be conveyed into the gas turbine 25 for combustion, so that the natural gas is prevented from forming pressure drop through the natural gas booster 27, the natural gas booster 27 is stopped, then the driving gas source for the switching action of the pneumatic quick opening and closing valve 30 is supplied by the gas source supply system 31, the pneumatic quick opening and closing valve 30 is opened, the natural gas is directly conveyed through the natural gas bypass pipeline 29, the transmission speed is improved, and unnecessary energy waste is reduced; when the upstream gas group gas supply pressure cannot meet the use requirement of the gas turbine 25, the pneumatic quick start-stop valve 30 is closed, the natural gas supercharger 27 normally operates to provide natural gas meeting the use requirement for the gas turbine 25, when the natural gas supercharger 27 breaks down and stops operating in the operation process, the pneumatic quick start-stop valve 30 is opened, the natural gas is conveyed by the natural gas bypass pipeline 29, the natural gas required by the gas turbine 25 cannot be supplied instantly, the gas turbine 25 can be guaranteed to be normally stopped in load shedding mode, and the unit is prevented from being stopped.
In a specific embodiment, the driving air source supplied by the air source supply system 31 can be selected from a plant compressed air main pipe, and the pressure of the driving air source used is about 0.8 MPa. In addition, the controller can also automatically control the opening of the pneumatic quick opening and closing valve 30, the controller monitors the running state of the natural gas supercharger 27 in real time, in the normal running process of the natural gas supercharger 27, the controller controls the pneumatic quick opening and closing valve 30 to keep the closing state, when the upstream gas group gas supply pressure directly meets the use requirement of the gas turbine, the controller controls the natural gas supercharger 27 and simultaneously opens the pneumatic quick opening and closing valve 30, natural gas is conveyed to the FGH system 35 through the natural gas bypass pipeline 29, and the natural gas is heated by the FGH system 35 and then conveyed into the gas turbine 25; meanwhile, when the natural gas booster 27 is monitored to have a fault, the controller controls the pneumatic quick opening and closing valve 30 to be opened, so that the natural gas supply is not interrupted, the automatic control of the bypass device is realized, and the action response is more sensitive and timely.
In the embodiment of the present invention, the joint of the gas turbine 25 and the housing of the gas turbine 25 are integrally welded by high pressure welding, the leakage risk points in the gas turbine 25 are all changed into a welding form, and the intrinsic safety of the natural gas system of the housing of the gas turbine 25 is ensured by using the characteristics of the reliability and the long-term property of the welding form.
In one embodiment, potential leak points in the casing of the gas turbine 25 are counted in the field, a ledger is recorded, and a list of spare parts required for high pressure welding, such as high pressure welding pin valves, high pressure welding tees, high pressure welding reducer joints, etc., is designed and counted based on the recorded ledger. The method comprises the steps of processing potential leakage points by using completely prepared materials and combining a high-pressure welding technology, finally achieving the purpose of totally sealing the leakage points, carrying out wind pressure inspection on the sealed joint position, carrying out secondary leakage inspection, recording related data, and confirming the safety and reliability of the joint position. The totally-enclosed treatment of the joint position of the gas turbine 25 by the high-pressure welding technology ensures that the joint position basically has no leakage problem within 5-10 years, reduces the work burden for on-site leakage point investigation, greatly improves the safe operation reliability of the gas turbine housing, and essentially improves the safety of a natural gas system of the gas turbine 25 housing.
In summary, the present specification discloses a gas-steam combined cycle unit capable of preventing natural gas leakage, which improves the safety and reliability of a natural gas system by connecting a bypass device in parallel at a natural gas booster. The quick opening and closing valve in the bypass device is opened and closed according to the real-time states of starting, stopping and the like of the natural gas supercharger, so that the investment cost of the natural gas supercharger is not increased, the natural gas of the gas turbine cannot be instantly supplied when the natural gas supercharger breaks down, the load shedding and normal stopping of the gas turbine can be guaranteed, and the non-stop of a unit is avoided. Simultaneously, still when air feed pressure can directly satisfy combustion engine user demand upstream, the natural gas booster compressor of stopping transport, through the direct supply natural gas of bypass device, avoid the natural gas to pass through the booster compressor and form the pressure drop, improved the economic benefits of power plant.
In addition, the problem of natural gas leakage in the housing of the gas turbine is solved by adopting a high-pressure welding technology, the problem of natural gas leakage of an instrument joint is fundamentally avoided, the problem that leakage points cannot be isolated during the operation of the unit is solved, important guarantee is provided for the intrinsic operation safety of the gas turbine unit, the work load is reduced for the local inspection of the natural gas leakage points, the safe operation reliability of the housing of the gas turbine is improved, and the safety of a housing natural gas system is essentially improved.
Those of ordinary skill in the art will understand that: the figures are schematic representations of one embodiment, and the blocks or processes in the figures are not necessarily required to practice the present invention.
Those of ordinary skill in the art will understand that: modules in the devices in the embodiments may be distributed in the devices in the embodiments according to the description of the embodiments, or may be located in one or more devices different from the embodiments with corresponding changes. The modules of the above embodiments may be combined into one module, or further split into multiple sub-modules.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present invention.
Claims (10)
1. The gas-steam combined cycle unit capable of preventing natural gas leakage is characterized by comprising a boiler system, a gas turbine system, a steam turbine system and a condenser system;
the boiler system comprises two waste heat boilers, two low-pressure steam drums, two medium-pressure steam drums, two high-pressure steam drums, two medium-pressure water feeding pumps, two high-pressure water feeding pumps, and a low-pressure economizer, a low-pressure evaporator, a low-pressure superheater, a medium-pressure economizer, a medium-pressure evaporator, a medium-pressure superheater, a reheater, a high-pressure economizer, a high-pressure evaporator and a high-pressure superheater which are arranged in each waste heat boiler; the two waste heat boilers are respectively in one-to-one correspondence with the two low-pressure steam drums, the two medium-pressure steam drums, the two high-pressure steam drums, the two medium-pressure water feeding pumps and the two high-pressure water feeding pumps; the water outlet end of the low-pressure economizer is communicated with the low-pressure steam drum; two ends of the low-pressure evaporator are respectively communicated with the low-pressure steam pocket; the steam inlet end of the low-pressure superheater is communicated with the low-pressure steam drum; the steam outlet end of the low-pressure superheater is connected with a low-pressure steam conveying pipeline; a low-pressure steam combining valve is arranged on the low-pressure steam conveying pipeline; the water inlet end of the medium-pressure economizer is communicated with the low-pressure steam pocket through the medium-pressure water feed pump; the water outlet end of the medium-pressure economizer is communicated with the medium-pressure steam drum; two ends of the medium-pressure evaporator are respectively communicated with the medium-pressure steam pocket; the steam inlet end of the intermediate-pressure superheater is communicated with the intermediate-pressure steam drum; the steam outlet end of the intermediate-pressure superheater is communicated with the steam inlet end of the reheater through an intermediate-pressure superheated steam conveying pipeline; the steam outlet end of the reheater is connected with a reheat steam conveying pipeline; a medium-pressure parallel valve is arranged on the reheating steam conveying pipeline; the water inlet end of the high-pressure economizer is communicated with the high-pressure steam pocket through the high-pressure water feed pump; the water outlet end of the high-pressure economizer is communicated with the high-pressure steam drum; two ends of the high-pressure evaporator are respectively communicated with the high-pressure steam pocket; the steam inlet end of the high-pressure superheater is communicated with the high-pressure steam drum; the steam outlet end of the high-pressure superheater is connected with a high-pressure steam conveying pipeline; a high-pressure steam combining valve is arranged on the high-pressure steam conveying pipeline;
the gas turbine system comprises two gas turbines, a natural gas conveying pipeline, a natural gas supercharger, a pneumatic control valve, a natural gas bypass pipeline, a pneumatic quick start and stop valve, a gas source supply system, a flap type check valve, a start and stop control valve, a controller, an FGH system and a first check valve; the two gas turbines correspond to the two waste heat boilers one by one; the gas inlet end of each waste heat boiler is communicated with one gas turbine; the joint of the gas turbine and the housing of the gas turbine are welded into a whole by adopting high pressure welding; one end of the natural gas conveying pipeline is communicated with a natural gas source, and the other end of the natural gas conveying pipeline is communicated with a fuel gas inlet end of the FGH system; the fuel outlet end of the FGH system is communicated with the natural gas inlet end of the gas turbine through a high-pressure steel pipe; the natural gas transmission pipeline is provided with the natural gas supercharger; the pneumatic control valve is installed on the natural gas conveying pipeline between the FGH system and the natural gas booster; the natural gas bypass pipeline is connected with the natural gas booster in parallel; the natural gas bypass pipeline is sequentially provided with the flap type check valve and the pneumatic quick opening and closing valve along the natural gas conveying direction; the air source supply system is communicated with the pneumatic quick opening and closing valve and supplies a driving air source required by the opening and closing action to the pneumatic quick opening and closing valve; the opening and closing control valve is arranged between the air source supply system and the pneumatic quick opening and closing valve; the water inlet end of the FGH system is communicated with the water outlet end of the medium-pressure economizer; the water outlet end of the FGH system is communicated with the water inlet end of the low-pressure economizer through the first check valve; the natural gas booster is electrically connected with the controller; the control end of the pneumatic quick opening and closing valve is electrically connected with the controller;
the steam turbine system comprises a high-pressure steam turbine, a medium-pressure steam turbine, a low-pressure steam turbine, a communicating pipe, a high-pressure steam exhaust main pipeline and a high-pressure steam exhaust branch pipeline which are coaxially connected; the steam outlet end of the medium-pressure turbine is communicated with the steam inlet end of the low-pressure turbine through the communicating pipe; the two low-pressure steam delivery pipelines are converged and then are connected to the communicating pipe together; the two reheat steam delivery pipelines are converged and then are connected to the steam inlet end of the medium-pressure steam turbine together; the two high-pressure steam conveying pipelines are converged and then are connected to the steam inlet end of the high-pressure turbine together; the steam outlet end of the high-pressure steam turbine is connected with the high-pressure steam exhaust main pipeline; two paths of high-pressure steam exhaust branch pipelines are led out from the high-pressure steam exhaust main pipeline; the two high-pressure steam exhaust branch pipelines are respectively communicated with the two medium-pressure superheated steam conveying pipelines;
the condenser system comprises a condenser and a condensate pump; and the water outlet end of the condenser is respectively communicated with the water inlet ends of the two low-pressure coal economizers through the condensate pump.
2. The gas-steam combined cycle plant capable of preventing natural gas leakage according to claim 1, wherein the reheater comprises a primary reheater, a secondary reheater; the steam inlet end of the primary reheater is connected with the medium-pressure superheated steam conveying pipeline; the steam outlet end of the primary reheater is communicated with the steam inlet end of the secondary reheater; and the steam outlet end of the secondary reheater is connected with the reheat steam conveying pipeline.
3. The gas-steam combined cycle plant capable of preventing natural gas leakage according to claim 1, wherein a second check valve is installed on the medium-pressure superheated steam delivery pipe.
4. The gas-steam combined cycle unit for preventing leakage of natural gas according to claim 1, wherein a third check valve is installed on the high pressure exhaust branch pipe.
5. The gas-steam combined cycle unit capable of preventing natural gas leakage according to claim 1, wherein a high-pressure bypass pressure regulating valve is arranged between the high-pressure steam delivery pipeline and the high-pressure steam exhaust branch pipeline.
6. The gas-steam combined cycle unit capable of preventing natural gas leakage according to claim 1, wherein a low-pressure bypass connected with the condenser is led out from the low-pressure steam delivery pipeline, and a low-pressure bypass pressure regulating valve is installed on the low-pressure bypass.
7. The gas-steam combined cycle unit capable of preventing natural gas leakage according to claim 1, wherein a medium-pressure bypass connected with the condenser is led out from the reheat steam delivery pipeline, and a medium-pressure bypass pressure regulating valve is installed on the medium-pressure bypass.
8. The gas-steam combined cycle plant capable of preventing natural gas leakage according to claim 1, further comprising a generator system;
the generator system comprises two gas turbine generators and a steam turbine generator; each gas turbine generator is coaxially connected with one gas turbine and driven by the gas turbine to generate power; the steam turbine generator is coaxially connected with the high-pressure turbine and driven by the high-pressure turbine, the medium-pressure turbine and the low-pressure turbine to generate electricity.
9. The gas-steam combined cycle unit capable of preventing natural gas leakage according to claim 1, wherein the low-pressure parallel valve, the medium-pressure parallel valve and the high-pressure parallel valve are all electrically operated valves.
10. The gas-steam combined cycle plant capable of preventing natural gas leakage according to claim 1, wherein the combustion engine system further comprises an air heat exchanger; and the air inlet end of the gas turbine is connected with the air heat exchanger.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120539698.XU CN214887268U (en) | 2021-03-16 | 2021-03-16 | Gas-steam combined cycle unit capable of preventing natural gas leakage |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120539698.XU CN214887268U (en) | 2021-03-16 | 2021-03-16 | Gas-steam combined cycle unit capable of preventing natural gas leakage |
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| CN214887268U true CN214887268U (en) | 2021-11-26 |
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| CN202120539698.XU Withdrawn - After Issue CN214887268U (en) | 2021-03-16 | 2021-03-16 | Gas-steam combined cycle unit capable of preventing natural gas leakage |
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2021
- 2021-03-16 CN CN202120539698.XU patent/CN214887268U/en not_active Withdrawn - After Issue
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