CN108625990B - Natural gas oxygen-enriched combustion and transcritical CO2Cyclic coupled power generation system - Google Patents
Natural gas oxygen-enriched combustion and transcritical CO2Cyclic coupled power generation system Download PDFInfo
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- CN108625990B CN108625990B CN201810331141.XA CN201810331141A CN108625990B CN 108625990 B CN108625990 B CN 108625990B CN 201810331141 A CN201810331141 A CN 201810331141A CN 108625990 B CN108625990 B CN 108625990B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas- turbine plants for special use
- F02C6/18—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas- turbine plants for special use using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
- F01K25/10—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours the vapours being cold, e.g. ammonia, carbon dioxide, ether
- F01K25/103—Carbon dioxide
Abstract
The invention discloses combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2And (4) circularly coupling the power generation system. By means of H2The combustion temperature is neutralized by O, a flue gas circulating system is omitted, the circulating water is pressurized in a liquid phase, and the energy consumption is reduced. O is2/H2The water content in the flue gas generated by O combustion is high, the latent heat of vaporization of water vapor in the flue gas is difficult to utilize in the traditional combined cycle mode, and the invention adopts gas-steam combined cycle and transcritical CO2The heat energy of the flue gas can be fully utilized in a circulating coupling mode, so that the power generation efficiency of the system is obviously improved. Furthermore, LNG cold energy is sequentially used for CO in flue gas2Capture, transcritical CO of2And the working medium is condensed in the circulation to reduce the power consumption of carbon capture and ensure the stable operation of transcritical circulation, thereby realizing the high-efficiency utilization of cold energy and the remarkable improvement of the power generation efficiency of the system.
Description
Technical Field
The invention belongs to the field of natural gas power generation, and particularly relates to natural gas oxygen-enriched combustion and trans-critical CO2A cyclically coupled power generation system.
Background
The efficiency of coal-fired power generation is very low and the environmental problems are very serious. The energy utilization efficiency is improved, and the adjustment of the energy structure is very important for China. The pollutants discharged by natural gas power generation are very few, the power generation mode which is most widely applied and has the most mature technology in a natural gas power plant is combined cycle at present, and the power generation efficiency is more than 50%.
In addition, as the greenhouse effect is increasing, Carbon Capture and Sequestration (CCS) technology is receiving more and more attention. Among them, oxygen-enriched combustion is one of the most easily realized large-scale carbon capture technologies, and can capture CO in flue gas2The content is improved to more than 80 percent. But condensing CO2Still consume a large amount of energy. At present, LNG and air are generally directly subjected to heat exchange and gasification in an LNG power plant, and cold energy of the LNG and air is almost completely wasted.
In oxygen-enriched combustion, the combustion temperature neutralizing medium widely used at present is CO2And H2O。 O2/CO2The system is additionally provided with a flue gas compression circulation system, and the electrical efficiency of system output is reduced. O is2/H2The O oxygen-enriched combustion flue gas contains a large amount of H2O, even if the gas-steam combined cycle is adopted, the heat in the flue gas cannot be fully utilized, the temperature of the flue gas discharged by the waste heat boiler is about 100 ℃, and the H in the flue gas2O is present in the gas phase, resulting in system inefficiency.
Disclosure of Invention
In response to the above-mentioned deficiencies or needs in the art, the present invention provides a natural gas oxycombustion and transcritical CO2The power generation system is circularly coupled, and the carbon capture with high efficiency and low cost of the natural gas power plant is realized by using the LNG cold energy. The system combines gas turbine power generation, steam Rankine cycle, and transcritical CO2The circulation is organically combined, so that the heat energy in the flue gas is fully utilized and converted into electric energy, and the power generation efficiency of a power plant is improved; oxygen-enriched combustion using H2O is used as a combustion temperature neutralizing medium, a flue gas circulating system is omitted, the pressurization process is liquid phase pressurization, the compression power consumption is saved, and the problem that the prior art is based on the prior art is solvedThe power generation system for the oxygen-enriched combustion of the natural gas has the technical problems of low power generation efficiency, waste of cold energy and the like.
To achieve the above objects, according to one aspect of the present invention, there is provided a natural gas oxycombustion and transcritical CO2A cycle coupled power generation system comprising a natural gas oxycombustion gas turbine cycle with water as a combustion temperature neutralizing medium; the natural gas oxygen-enriched combustion gas turbine specifically comprises a combustion chamber, a gas turbine, a waste heat boiler, a heat exchanger, a flue gas water separator, a water separator and a water pump which are sequentially connected through a pipeline; when the device works, oxygen, circulating water separated from the flue gas water separator and natural gas for combustion are mixed and then combusted in the combustion chamber to generate main flue gas;
the main flue gas enters the gas turbine to do work through expansion, and exhaust of the gas turbine is obtained after the work is done;
the exhaust gas of the gas turbine enters the waste heat boiler to provide heat for steam Rankine cycle, and flue gas exhausted by the waste heat boiler is obtained;
the flue gas discharged by the waste heat boiler enters the heat exchanger as transcritical CO2A circulating heat source for gasifying the transcritical CO2The liquid working medium in the circulation exchanges heat to obtain the flue gas discharged by the heat exchanger;
the flue gas discharged by the heat exchanger enters the flue gas water separator to be treated by CO2The flue gas mainly flows out from the top of the flue gas water separator and then enters CO2A liquefaction plant; after flowing out from the bottom, the liquid water separated by the flue gas water separator is divided into two parts by the water separator, one part is directly discharged out of the system, and the other part is pressurized by the water pump and then returns to the combustion chamber to be used as a combustion temperature neutralizing medium.
Preferably, the steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator and a high-pressure water pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into two parts through the water separator, and heating one part of the preheated circulating water sequentially through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; and the other part of the high-pressure water is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust and the low-pressure superheated steam are merged by the confluence device and then enter the low-pressure turbine to do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust enters the condenser to be condensed into liquid water, and the liquid water is circulating water for the steam Rankine cycle.
Preferably, the steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a reheat steam turbine, a flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator and a high-pressure water pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a reheater, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into two parts through the water separator, and heating one part of the preheated circulating water sequentially through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; and the other strand of the high-pressure water is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust enters the reheater to be reheated to obtain reheated steam, the reheated steam enters the reheater turbine to do work to obtain reheated turbine exhaust, the reheated turbine exhaust and the low-pressure superheated steam are combined by the combiner and then enter the low-pressure turbine to do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust enters the condenser to be condensed into liquid water, and the liquid water is circulating water for the steam Rankine cycle.
Preferably, the steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a medium-pressure steam turbine, a second flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator, a high-pressure water pump and a medium-pressure pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a high-pressure second-stage economizer, a low-pressure superheater, a medium-pressure evaporator, a medium-pressure economizer, a high-pressure first-stage economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into three strands through the water separator, and heating one strand of circulating water sequentially flowing through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into the medium-pressure pump to be pressurized and is sequentially sent into the medium-pressure economizer, the medium-pressure evaporator and the medium-pressure superheater to be heated into medium-pressure superheated steam; and the other strand of the waste steam is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure first-stage economizer, the high-pressure second-stage economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust and the medium-pressure superheated steam are mixed and then enter the medium-pressure turbine to do work to obtain low-pressure exhaust steam, the low-pressure exhaust steam and the low-pressure superheated steam are mixed and enter the low-pressure turbine to expand and do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust is condensed into liquid water by the condenser, and the liquid water.
Preferably, the steam rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a reheating medium-pressure steam turbine, a second flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator, a high-pressure water pump and a medium-pressure pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a reheater, a high-pressure evaporator, a medium-pressure superheater, a high-pressure second-stage economizer, a low-pressure superheater, a medium-pressure evaporator, a medium-pressure economizer, a high-pressure first-stage economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into three strands through the water separator, and heating one strand of circulating water sequentially flowing through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into the medium-pressure pump to be pressurized and is sequentially sent into the medium-pressure economizer, the medium-pressure evaporator and the medium-pressure superheater to be heated into medium-pressure superheated steam; the other end is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure first-stage economizer, the high-pressure second-stage economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the exhaust gas of the high pressure turbine is mixed with the medium pressure superheated steam and then enters the reheater for reheating to obtain reheated steam, the reheated steam enters the medium pressure turbine to do expansion work to obtain medium pressure turbine exhaust, the exhaust gas of the medium pressure turbine and the low pressure superheated steam are mixed and enter the low pressure turbine to expand and do work to obtain the exhaust gas of the low pressure turbine, and the exhaust gas of the low-pressure turbine is condensed into liquid water through the condenser, and the liquid water is circulating water for the steam Rankine cycle.
Preferably, the combined cycle power system further comprises CO2A liquefaction system, said flue gas separator separated from the top with CO2Flue gas mainly containing gas through CO2The compressor pressurizes and then feeds CO2The condensing heat exchanger exchanges heat with high-pressure LNG (liquefied natural gas), and CO in the flue gas2The gas is condensed into liquid, is discharged from the bottom and collected after being separated by a gas-liquid separator, and other non-condensable gases in the flue gas are directly discharged from the top of the gas-liquid separator; the high-pressure LNG is gasified into low-temperature natural gas after heat exchange, and enters the trans-critical CO2The circulation provides cold energy for the device.
Preferably, the transcritical CO is2The circulation comprises a heat exchanger and CO which are connected in sequence through a pipeline2Turbine, cryogenic condenser and CO2A working medium pump; when the waste heat boiler works, the flue gas discharged by the waste heat boiler enters the heat exchanger to be mixed with the circulating working medium CO2Heat exchange, liquid CO2Heat absorbed and gasified and enters into the CO2Expanding in turbine to do work, and then CO2Pressure reduction of gas, CO after work2Gas enters the low-temperature condenser to exchange heat with the low-temperature natural gas, and CO is obtained2The gas is condensed into liquid CO2Said liquid CO2Into the CO2Pressurizing in the working medium pump and entering the heat exchanger for heat absorption and gasification to form the transcritical CO2And (6) circulating.
Preferably, the LNG is first pressurized by an LNG pump to form the high-pressure LNG, and the high-pressure LNG is first pressurized by the CO2Condensing CO separated from the top of the flue gas water separator by a condensing heat exchanger2The predominantly flue gas then passes through the cryogenic condenser, condensing the transcritical CO2Circulating working medium CO in the cycle2And finally, gasifying and heating the LNG to normal-temperature natural gas, wherein the normal-temperature natural gas is divided into two parts by a natural gas splitter, one part is used as fuel required by oxygen-enriched combustion, and the other part is merged into a natural gas pipe network to be used as pipe-transported natural gas.
Preferably, the temperature of the combustion chamber is controlled by regulating the flow rate of circulating water introduced into the combustion chamber, and the flow rate of circulating water in the system is determined according to the highest temperature which can be borne by the equipment, so as to ensure that the combustion temperature does not exceed the maximum allowable operating temperature of the equipment.
In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:
1. combined cycle and transcritical CO as described in the present invention2The circulating coupling power system is based on the technical route of oxygen-enriched combustion, and utilizes CO in natural gas oxygen-enriched combustion flue gas2And H2The high concentration of O directly converts H in the flue gas2Condensing and separating O to obtain high-concentration CO2And simultaneously utilizes LNG cold energy to separate CO from the flue gas2The carbon capture with lower cost of the natural gas power plant can be realized by condensation;
2. the invention adopts H2O is used as a combustion temperature neutralizing medium, on one hand, a smoke circulating system is omitted, so that the system device is simpler and the arrangement is more compact, on the other hand, the pressurizing process of liquid water is realized through a water pump, and compared with the compression work of a compressor, the power consumption of the system is reduced;
3. the invention adopts combined cycle and transcritical CO2The power system coupled in a circulating way can fully utilize the heat energy of the flue gas generated by combustion and convert the heat energy into electric energy, and the power generation efficiency of the system can be obviously improved.
4. The design of different steam Rankine cycle systems is adopted, so that the requirements of power plants of different scales are met.
Drawings
FIG. 1 is a combined cycle and transcritical CO based natural gas oxycombustion according to example 1 of the invention2Circularly coupling the technological process of the power system;
FIG. 2 is a combined cycle and transcritical CO based natural gas oxycombustion according to example 2 of the invention2Circularly coupling the technological process of the power system;
FIG. 3 is a combined cycle and transcritical CO based natural gas oxycombustion according to example 3 of the invention2And (5) circularly coupling the process flow of the power system.
The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:
1-a combustion chamber; 2-a gas turbine; 3, a waste heat boiler; 4, a heat exchanger; 5-flue gasA water separator; 6, a water separator; 7, a water pump; 8-CO2A compressor; 9-CO2A condensing heat exchanger; 10-gas-liquid separator; 11-LNG pump; 12-a low temperature condenser; 13-natural gas splitter; 14-CO2A working medium pump; 15-CO2A turbine; 16-a low-pressure water pump; 17-a water separator; 18-high pressure water pump; 19-a high pressure turbine; 20-a flow combiner; 21-a low pressure turbine; 22-a condenser; 23-a reheat turbine; 24-a medium pressure pump; 25-a medium pressure turbine; 26-a second flow combiner; a1-low pressure economizer; a2 — low pressure evaporator; a3-high pressure economizer; a3-1-high pressure first stage economizer; a3-2-high pressure second stage economizer; a4 — low pressure superheater; a5 — high pressure evaporator; a6 — high pressure superheater; a7 — reheater; a8-medium pressure economizer; a9 — medium pressure evaporator; a10 — medium pressure superheater.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention provides natural gas oxygen-enriched combustion and trans-critical CO2The cycle coupled power generation system is a combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2The cycle coupling power system comprises a natural gas oxygen-enriched combustion gas turbine cycle which takes water as a combustion temperature neutralizing medium; the natural gas oxygen-enriched combustion gas turbine specifically comprises a combustion chamber, a gas turbine, a waste heat boiler, a heat exchanger, a flue gas water separator, a water separator and a water pump which are sequentially connected through a pipeline; when in use, the utility model is used for cleaning the inner wall of the tank,
mixing high-concentration oxygen with the volume fraction of 95-98%, circulating water separated from a flue gas water separator and natural gas for combustion, and then combusting in a combustion chamber to generate high-temperature and high-pressure main flue gas, wherein the pressure of the high-temperature and high-pressure main flue gas is 3.5-9.0 MPa, and the temperature is 1250-1400 ℃;
the high-temperature high-pressure flue gas enters a gas turbine to perform expansion work, and high-temperature exhaust gas of the gas turbine is obtained after the work is performed, wherein the high-temperature exhaust gas pressure of the gas turbine is one atmosphere and the temperature is 600-700 ℃;
high-temperature exhaust gas of the gas turbine enters a waste heat boiler to provide heat for steam Rankine cycle, so that flue gas discharged by the waste heat boiler is obtained, and the temperature of the flue gas discharged by the waste heat boiler is 120-150 ℃;
the flue gas discharged from the waste heat boiler enters a heat exchanger as transcritical CO2The liquid working medium in the circulation is gasified by a circulating heat source, and the temperature of the flue gas discharged by a heat exchanger is reduced to 30-50 ℃;
the flue gas discharged from the heat exchanger enters a flue gas water separator to be treated with CO2The flue gas mainly flows out from the top of the flue gas water separator and then enters CO2A liquefaction plant; after flowing out from the bottom, the liquid water separated by the flue gas water separator is divided into two parts by the water separator, one part is directly discharged out of the system, and the other part is pressurized by a water pump and then returns to the combustion chamber to be used as a combustion temperature neutralizing medium. The temperature of the combustion chamber can be controlled by adjusting the flow of circulating water introduced into the combustor, and the flow of circulating water of the system is determined according to the highest temperature which can be borne by the equipment, so as to ensure that the combustion temperature does not exceed the maximum allowable operating temperature of the equipment.
The steam Rankine cycle of the invention can be set in various ways, 4 of which are as follows:
(1) the steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator and a high-pressure water pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from a hot end to a cold end; and the other high-pressure water is pressurized by a high-pressure water pump to obtain high-pressure water with the high-pressure of 8-10 MPa, the high-pressure water sequentially flows through a high-pressure economizer, a high-pressure evaporator and a high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters a high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust gas, the high-pressure turbine exhaust gas pressure is 0.3-0.5 MPa and the temperature is 200-250 ℃, the high-pressure turbine exhaust gas and the low-pressure superheated steam are combined by a combiner and then enter a low-pressure turbine to do work to obtain low-pressure turbine exhaust gas, the low-pressure turbine exhaust gas pressure is 8-10 kPa, the low-pressure turbine exhaust gas enters a condenser to be condensed into liquid water, the liquid water is circulating water. And then the pressure is increased to different pressures through different water pumps, and the pressure is introduced into the waste heat boiler to exchange heat with the exhaust gas of the gas turbine, so that the double-pressure non-reheat steam Rankine cycle is formed.
(2) The steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a reheat steam turbine, a flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator and a high-pressure water pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a reheater, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from a hot end to a cold end, when the waste heat boiler works, circulating water for the steam Rankine cycle is pressurized to 0.3-0.5 MPa through the low-pressure water pump and is input into the low-pressure economizer for preheating, the preheated circulating water is divided into two parts through the water separator, and one part of the two parts sequentially flows through the low-pressure evaporator; the other high-pressure water is pressurized by the high-pressure water pump to obtain high-pressure water with the high-pressure of 8-10 MPa, the high-pressure water sequentially flows through a high-pressure economizer, a high-pressure evaporator and a high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters a high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust gas, the high-pressure turbine exhaust gas pressure is 1.5-2.5 MPa, the high-pressure turbine exhaust gas enters a reheater to be reheated to obtain reheated steam after reheating, the reheated steam is 550 ℃ in temperature, the reheated steam enters a reheater turbine to do work to obtain reheated turbine exhaust gas after doing work, the reheated turbine exhaust gas pressure is 0.3-0.5 MPa and 200-250 ℃, the reheated turbine exhaust gas and the low-pressure superheated steam are combined by the combiner to enter a low, and the exhaust gas of the low-pressure turbine enters a condenser and is condensed into liquid water, the liquid water is circulating water for the steam Rankine cycle, and the flow distribution of a water separator in the high-pressure steam Rankine cycle can be freely combined. And then the pressure is increased to different pressures through different water pumps, and the pressure is introduced into the waste heat boiler to exchange heat with the exhaust gas of the gas turbine, so that the double-pressure reheating steam Rankine cycle is formed.
(3) The steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a medium-pressure steam turbine, a second flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator, a high-pressure water pump and a medium-pressure pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a high-pressure second-stage economizer, a low-pressure superheater, a medium-pressure evaporator, a medium-pressure economizer, a high-pressure first-stage economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end, pressurizing the circulating water for the steam Rankine cycle to a low-pressure of 0.3-0.5 MPa by a low-pressure water pump, inputting the circulating water into a low-pressure economizer for preheating, dividing the preheated circulating water into three strands through a water separator, and heating one strand of circulating water sequentially flowing through a low-pressure evaporator and a low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into a medium-pressure pump to be pressurized to 2-3 MPa, and is sequentially fed into a medium-pressure economizer, a medium-pressure evaporator and a medium-pressure superheater to be heated into medium-pressure superheated steam; and pressurizing the other strand of the waste steam by a high-pressure water pump to obtain high-pressure water with the high-pressure of 10-12 MPa, allowing the high-pressure water to sequentially flow through a high-pressure first-stage economizer, a high-pressure second-stage economizer, a high-pressure evaporator and a high-pressure superheater and be pressurized into high-pressure superheated steam, allowing the high-pressure superheated steam to enter a high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust gas, allowing the high-pressure turbine exhaust gas to reach 2-3 MPa, allowing the high-pressure turbine exhaust gas and the medium-pressure superheated steam to enter a medium-pressure turbine to do work after being mixed, obtaining low-pressure exhaust steam, allowing the low-pressure exhaust steam and the low-pressure superheated steam to reach the pressure of 0.3-0.5 MPa, allowing the low-pressure exhaust steam and the low-pressure superheated steam to be mixed and enter a low. The flow distribution of the water separators in the high pressure steam rankine cycle can be freely combined. The three streams of water flow are pressurized to three different pressures by a water pump and enter the waste heat boiler again for heat absorption and gasification to form a three-pressure non-reheat steam Rankine cycle.
(4) The steam Rankine cycle comprises a waste heat boiler, a high-pressure steam turbine, a flow combiner, a reheating medium-pressure steam turbine, a second flow combiner, a low-pressure steam turbine, a condenser, a low-pressure water pump, a water separator, a high-pressure water pump and a medium-pressure pump, wherein the waste heat boiler sequentially comprises a high-pressure superheater, a reheater, a high-pressure evaporator, a medium-pressure superheater, a high-pressure second-stage economizer, a low-pressure superheater, a medium-pressure evaporator, a medium-pressure economizer, a high-pressure first-stage economizer, a low-pressure evaporator and a low-pressure economizer which are connected through pipelines from the hot end to the cold end, pressurizing the circulating water for the steam Rankine cycle to a low-pressure of 0.3-0.5 MPa by a low-pressure water pump, inputting the circulating water into a low-pressure economizer for preheating, dividing the preheated circulating water into three strands through a water separator, and heating one strand of circulating water sequentially flowing through a low-pressure evaporator and a low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into a medium-pressure pump to be pressurized to 2-3 MPa, and is sequentially fed into a medium-pressure economizer, a medium-pressure evaporator and a medium-pressure superheater to be heated into medium-pressure superheated steam; the other strand of the exhaust gas is pressurized by a high-pressure water pump to obtain high-pressure water with the high-pressure of 10-12 MPa, the high-pressure water sequentially flows through a high-pressure first-stage economizer, a high-pressure second-stage economizer, a high-pressure evaporator and a high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters a high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust gas, the high-pressure turbine exhaust gas pressure is 2-3 MPa, the high-pressure turbine exhaust gas and the medium-pressure superheated steam are mixed and then enter a reheater to be reheated to obtain reheated steam, the temperature of the reheated steam is 550-600 ℃, the reheated steam enters a medium-pressure turbine to be expanded and do work to obtain medium-pressure turbine exhaust gas, the medium-pressure turbine exhaust gas pressure is 0.3-0.5 MPa, the medium-pressure, and (4) condensing the exhaust gas of the low-pressure turbine into liquid water through a condenser, wherein the liquid water is circulating water for the steam Rankine cycle. The flow distribution of the water separators in the high pressure steam rankine cycle can be freely combined. The three streams of water flow are pressurized to three different pressures by a water pump and enter the waste heat boiler again for heat absorption and gasification to form a three-pressure reheating steam Rankine cycle.
The combined cycle power system of the present invention also includes CO2Liquefaction system with flue gas separator separated from top by CO2Flue gas mainly containing gas through CO2Pressurizing to 0.6-1.0 MPa by a compressor, and then introducing CO2The condensing heat exchanger exchanges heat with high-pressure LNG with the pressure of 3.5-9.0 MPa, and CO in the flue gas2The gas is condensed into liquid, is discharged from the bottom and collected after being separated by the gas-liquid separator, and other non-condensable gases in the flue gas are directly discharged from the top of the gas-liquid separator; non-condensable gases such as O2Or N2(ii) a High-pressure LNG with the pressure of 3.5-9.0 MPa is gasified into low-temperature natural gas with the temperature of-150 to-120 ℃ after heat exchange, and enters into transcritical CO2The circulation provides cold energy for the device.
Transcritical CO of the invention2The circulation comprises a heat exchanger and CO which are connected in sequence through a pipeline2Turbine, cryogenic condenser and CO2A working medium pump; when in work, the flue gas discharged by the waste heat boiler enters the heat exchanger to be mixed with the circulating working medium CO2Heat exchange, liquid CO2Heat is absorbed and gasified and enters CO2Expansion work-applying and post-work-applying CO in turbine2The pressure of the gas is reduced to 0.6-0.8 MPa, and the CO after acting2The gas enters a low-temperature condenser to exchange heat with low-temperature natural gas at the temperature of-150 to-120 ℃, and CO2The gas is condensed into liquid CO2Liquid CO2Into CO2The working medium is pressurized in the working medium pump and enters the heat exchanger to absorb heat and gasify to form transcritical CO2And (6) circulating.
The LNG is pressurized into high-pressure LNG by an LNG pump, the pressure is 3.5-9.0 MPa, and the high-pressure LNG is pressurized into high-pressure LNG by CO2CO separated from the top of the condensation flue gas water separator of the condensation heat exchanger2The flue gas mainly passes through a low-temperature condenser to condense transcritical CO2Circulating working medium CO in the cycle2And finally, condensing and gasifying the LNG into normal-temperature natural gas (15-25 ℃), wherein the natural gas is divided into two parts by a natural gas splitter, one part is used as fuel required by oxygen-enriched combustion, and the other part is merged into a natural gas pipe network to be used as pipe-conveying natural gas. The LNG amount required by the system is condensed by CO in the flue gas2And CO in the transcritical cycle2The amount of cold required determines.
The invention discloses combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2A cycle coupled power generation system comprising a high pressure O2/H2O-fired gas turbine cycle, high pressure steam Rankine cycle, transcritical CO2CO recycling and utilizing LNG cold energy2A separation liquefaction system. The invention adopts H2The combustion temperature is neutralized by O, a flue gas circulating system is omitted, the circulating water is pressurized in a liquid phase, and the energy consumption is reduced. O is2/H2The water content in the flue gas generated by O combustion is high, the latent heat of vaporization of water vapor in the flue gas is difficult to utilize in the traditional combined cycle mode, and the invention adopts gas-steam combined cycle and transcritical CO2The heat energy of the flue gas can be fully utilized in a circulating coupling mode, so that the power generation efficiency of the system is obviously improved. Furthermore, LNG cold energy is sequentially used for CO in flue gas2Capture, transcritical CO of2And the working medium is condensed in the circulation to reduce the power consumption of carbon capture and ensure the stable operation of transcritical circulation, thereby realizing the high-efficiency utilization of cold energy and the remarkable improvement of the power generation efficiency of the system.
The following are examples:
example 1
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2The technological process of the circulating coupling power system is shown in figure 1, and the specific process is as follows:
(1) high pressure O2/H2O-fired gas turbine cycle
High pressure O with molar concentration higher than 95%2And from combustion flue gasesThe discharged circulating water and the high-pressure natural gas for combustion are mixed and then enter the combustion chamber 1 for combustion, the combustion pressure is 3.0-9.0 MPa, and high-temperature and high-pressure flue gas with the temperature of 1250-1400 ℃ is generated. The flue gas enters a gas turbine 2 to expand and do work, the pressure is reduced to be slightly higher than the environmental pressure, and the temperature is reduced to 600-700 ℃. High-temperature exhaust gas of the gas turbine enters the waste heat boiler 3 to provide heat for the steam Rankine cycle, and the temperature is reduced to 120-150 ℃. The flue gas flowing out of the waste heat boiler enters the heat exchanger 4 as transcritical CO2The circulating heat source is used for gasifying the liquid working medium in the circulation, and the temperature is further reduced to 50 ℃. The normal pressure low temperature flue gas enters a flue gas water separator 5, gas-liquid phase fluid is separated according to different states of the fluid, and CO is used2The mainly gaseous flue gas flows out from the top of the flue gas water separator and then enters CO2A liquefaction plant; liquid H2And O flows out from the bottom of the flue gas water separator, is divided into two parts by the water separator 6, one part is directly discharged, and the other part is pressurized by the water pump 7 and then returns to the combustion chamber 1 of the gas turbine to form the circulation of the high-pressure oxygen-enriched combustion gas turbine.
(2) High pressure steam Rankine cycle
And (2) normal-pressure flue gas discharged from the gas turbine in the step (1) and with the temperature of 600-700 ℃ is sent into a waste heat boiler 3 to provide heat for the steam Rankine cycle. The circulating water is pressurized to a low-pressure of 0.3-0.5 MPa in a low-pressure water pump 16, and then enters a low-pressure economizer A1 of the waste heat boiler for preheating, and the temperature is raised to 50-70 ℃. The preheated low-pressure circulating water is divided into two parts by a water separator 17, and one part of the low-pressure circulating water sequentially flows through a low-pressure evaporator A2 and a low-pressure superheater A4 in the waste heat boiler 3 and is heated into low-pressure superheated steam at the temperature of 200-250 ℃; the other part is further pressurized to a high pressure of 8-10 MPa by a high pressure water pump 18, and the part of high pressure water sequentially flows through a high pressure economizer A3, a high pressure evaporator A5 and a high pressure superheater A6 in the waste heat boiler 3 to be heated into high pressure superheated steam with the temperature of 550-600 ℃. The high-pressure superheated steam enters the high-pressure turbine 19 to perform expansion work, the pressure is directly reduced to 0.3-0.5 MPa, the high-pressure turbine exhaust and the low-pressure superheated steam are mixed in the confluence device 20 and then enter the low-pressure turbine 21 to perform expansion work, and the pressure is reduced to 8-10 kPa, so that the exhaust dryness of the low-pressure turbine 21 is ensured to be larger than 88%. The exhaust gas of the steam turbine enters the condenser 22 again to be condensed into liquid water, and the liquid water is pressurized by the water pump and then is sent into the waste heat boiler 3 to exchange heat with the exhaust gas of the gas turbine 2, so that a double-pressure reheating-free high-pressure steam Rankine cycle is formed.
(3) CO utilizing LNG cold energy2Liquefaction system
The flue gas flowing out of the top of the flue gas water separator in the step (1) is pressurized to 0.6MPa by a compressor 8 and then enters CO2The condensing heat exchanger 9 exchanges heat with LNG (liquefied Natural gas), and CO in flue gas2Condensing into liquid state in the process, wherein the temperature is-55 ℃, and then discharging from the bottom through a gas-liquid separator 10 and collecting; other non-condensable gases, e.g. residual O2A small amount of N2When the gas is discharged from the top of the gas-liquid separator 10 directly; LNG in CO2Absorbing heat in the condensing heat exchanger 9 and gasifying the heat into low-temperature natural gas, raising the temperature to-110 ℃, and then entering into transcritical CO2The circulating system provides cold energy for the cooling system.
(4) Transcritical CO2Circulation of
The exhaust gas of the waste heat boiler 3 in the step (2) enters a heat exchanger 4 to be trans-critical CO2The circulation provides heat. The flue gas with the temperature of 150 ℃ is mixed with the circulating working medium CO in the heat exchanger 42Heat exchange, liquid CO2Absorbing heat, gasifying, expanding and acting in a turbine 15, reducing the pressure to 0.8-1.6 MPa, then entering a low-temperature condenser 12 to exchange heat with the low-temperature natural gas with the temperature of-110 ℃ obtained in the step (3), and circulating working medium CO2Namely condensed into liquid state, then enters a circulating working medium pump 14 to be pressurized to 7.4-15.4 MPa, and enters a heat exchanger 4 to absorb heat and gasify to form transcritical CO2And (6) circulating.
LNG is pressurized to gas turbine inlet pressure via LNG pump 11, and then to CO2Absorbing heat in the condensing heat exchanger 9 and the low-temperature condenser 12, heating to a temperature close to the ambient temperature, then entering the natural gas splitter 13 to be divided into two strands, wherein one strand is merged into a natural gas pipe network nearby to become a pipe-transported natural gas; and the other is input into a combustion chamber to be used as fuel of the system for combustion.
Combined cycle based on natural gas oxygen-enriched combustion and combined cycle based on natural gas oxygen-enriched combustion of the embodimentTranscritical CO2The overall net power generation efficiency of the circulating coupling power system is not lower than 56.5%.
Example 2
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2The technological process of the cycle coupling power system is shown in figure 2. This embodiment is different from embodiment 1 in that the reheating of steam is increased on the basis of the dual pressure non-reheat steam rankine cycle of the first embodiment 1. Compared with the system in the embodiment 1, the system is additionally provided with a reheater A7 and a reheat turbine 23. The high-pressure superheated steam generated in the high-pressure superheater A6 expands in the high-pressure turbine 19 to do work, the exhaust steam is reheated to 550 ℃ by the reheater A7 and then enters the reheat turbine 23 to do work in an expanding manner, the exhaust steam and the low-pressure superheated steam are mixed in the confluence device 20 and input into the low-pressure turbine 21 to do work in a turbine manner, the exhaust gas of the low-pressure turbine 21 enters the condenser 22 again to be condensed into liquid, and then the liquid is pressurized by the pump to form a double-pressure reheat steam Rankine cycle. The detailed arrangement of the heat exchangers in the waste heat boiler is shown in figure 2. The other procedures of the system are the same as those of example 1.
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion of the embodiment2The overall net power generation efficiency of the circulating coupling power system is not lower than 57.6%.
Example 3
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2The technological process of the cycle coupling power system is shown in figure 3. This embodiment differs from embodiment 1 in that an intermediate pressure stage is added to the dual pressure reheat-free steam rankine cycle. Compared with the system in the embodiment 1, the system is additionally provided with a medium-pressure pump 24, a medium-pressure turbine 25 and a flow combiner 26, and in addition, a high-pressure economizer is split into two parts, namely a high-pressure first-stage economizer A3-1 and a high-pressure low-stage economizer A3-2. The specific process is as follows: circulating water firstly enters a low-pressure pump 16 to be pressurized to the low-pressure of 0.3-0.5 MPa, then is preheated by a low-pressure economizer A1 and enters a water separator 17 to be divided into three strands, one strand of circulating water sequentially enters a low-pressure evaporator A2 and a low-pressure superheater A4 to absorb heat and is finally heated to the temperature of 2Low-pressure superheated steam at 50-300 ℃; one strand of the steam enters a medium-pressure pump 24 to be pressurized to medium-pressure of 2-3 MPa, and then enters a medium-pressure economizer A8, a medium-pressure evaporator A9 and a medium-pressure superheater A10 in sequence to be heated into medium-pressure superheated steam; the other strand of the steam enters a high-pressure pump to be heated to a high-pressure of 10-12 MPa, and then sequentially enters a high-pressure first-stage economizer A3-1, a high-pressure low-stage economizer A3-2, a high-pressure evaporator A5 and a high-pressure superheater A6 to be heated into high-pressure superheated steam, the high-pressure superheated steam with the temperature of 550-600 ℃ firstly enters a high-pressure turbine 19 to perform work by a turbine, the pressure is reduced to 2-3 MPa, exhaust steam and medium-pressure superheated steam are mixed in a confluence device 20 and are sent to the medium-pressure turbine 25 to perform work by expansion, the pressure is reduced to 0.3-0.5 MPa, the exhaust steam and the low-pressure superheated steam are mixed in the confluence device 26 and are input to a low-pressure turbine 21 to perform work, and the pressure is reduced to 8-10 kPa so as to ensure that the exhaust dryness of the; the exhaust steam is cooled and condensed in the condenser 22 to obtain liquid H2And O is input into the low-pressure pump again to be pressurized to a low-pressure, so that a three-pressure non-reheat steam Rankine cycle is formed. The detailed arrangement of the heat exchangers in the waste heat boiler is shown in figure 3. The other procedures of the system are the same as those of example 1.
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion of the embodiment2The overall net power generation efficiency of the circulating coupling power system is not lower than 56.7%.
Example 4
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion2And circularly coupling the power system. The present embodiment differs from embodiment 3 in that a steam reheating process is added on the basis of a three-pressure non-reheat steam Rankine cycle. Compared with the system in the embodiment 3, the system is additionally provided with a reheater A7 and a reheating medium-pressure turbine. The relevant process is as follows: after the high-pressure superheated steam expands in the high-pressure turbine 19 to do work, the exhaust steam and the medium-pressure superheated steam are mixed in the confluence device 20, the mixture firstly enters a reheater A7 to be reheated to 550 ℃, the obtained medium-pressure superheated steam enters the reheated medium-pressure turbine to be used as a turbine, the exhaust steam is mixed with the low-pressure superheated steam in the confluence device 26 and enters the low-pressure turbine 21 to do work in an expanding way, and the low-pressure superheated steam passes through the low-pressure turbine 21 to do workThe condenser 22 condenses to liquid H2And O, pressurizing by water pumps with different pressure levels to form a three-pressure reheating steam Rankine cycle. The other procedures of the system are the same as those of example 3.
Combined cycle and transcritical CO based on natural gas oxygen-enriched combustion of the embodiment2The overall net power generation efficiency of the circulating coupling power system is not lower than 58.3%.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. Natural gas oxygen-enriched combustion and transcritical CO2A cycle coupled power generation system comprising a natural gas oxycombustion gas turbine cycle having water as a combustion temperature neutralizing medium; the natural gas oxygen-enriched combustion gas turbine specifically comprises a combustion chamber, a gas turbine, a waste heat boiler, a heat exchanger, a flue gas water separator, a water separator and a water pump which are sequentially connected through a pipeline; when the device works, oxygen is mixed with circulating water separated from the flue gas water separator and natural gas for combustion and then is combusted in the combustion chamber to generate main flue gas;
the main flue gas enters the gas turbine to do work through expansion, and exhaust of the gas turbine is obtained after the work is done;
the exhaust gas of the gas turbine enters the waste heat boiler to provide heat for steam Rankine cycle, and flue gas exhausted by the waste heat boiler is obtained;
the flue gas discharged by the waste heat boiler enters the heat exchanger as transcritical CO2A circulating heat source for vaporizing the transcritical CO2The liquid working medium in the circulation exchanges heat to obtain the flue gas discharged by the heat exchanger; the temperature of the flue gas discharged by the heat exchanger is reduced to 30-50 ℃;
the trans-critical CO2The circulation comprises the heat exchanger and CO which are connected in sequence through pipelines2Turbine, cryogenic condenser and CO2Working mediumA pump; when the waste heat boiler works, the flue gas discharged by the waste heat boiler enters the heat exchanger to be mixed with the circulating working medium CO2Heat exchange, liquid CO2Heat is vaporized and enters the CO2Expansion work-applying and post-work-applying CO in turbine2Pressure reduction of gas, CO after work2Gas enters the low-temperature condenser to exchange heat with low-temperature natural gas, and CO is obtained2The gas is condensed into liquid CO2Said liquid CO2Into the CO2Pressurizing in the working medium pump and entering the heat exchanger to absorb heat and vaporize to form the transcritical CO2Circulating;
the flue gas discharged by the heat exchanger enters the flue gas water separator to be treated by CO2The flue gas mainly flows out from the top of the flue gas water separator and then enters CO2A liquefaction plant; after the liquid water separated by the flue gas water separator flows out from the bottom, the liquid water is divided into two parts by the water separator, one part is directly discharged out of the system, and the other part is pressurized by the water pump and then returns to the combustion chamber to be used as a combustion temperature neutralizing medium;
CO separated from the top of the flue gas water separator2Flue gas mainly containing gas through CO2The compressor pressurizes and then feeds CO2The condensing heat exchanger exchanges heat with high-pressure LNG (liquefied natural gas), and CO in the flue gas2The gas is condensed into liquid, is discharged from the bottom and collected after being separated by a gas-liquid separator, and other non-condensable gases in the flue gas are directly discharged from the top of the gas-liquid separator; the high-pressure LNG is vaporized into the low-temperature natural gas after heat exchange and enters the trans-critical CO2The circulation provides cold energy for the device.
2. The power generation system of claim 1, wherein the steam Rankine cycle comprises a waste heat boiler, a high pressure turbine, a flow combiner, a low pressure turbine, a condenser, a low pressure water pump, a water separator, and a high pressure water pump, wherein the waste heat boiler comprises a high pressure superheater, a high pressure evaporator, a low pressure superheater, a high pressure economizer, a low pressure evaporator, and a low pressure economizer connected by piping in sequence from hot end to cold end, and wherein, in operation,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into two parts through the water separator, and heating one part of the preheated circulating water sequentially through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; and the other part of the high-pressure water is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust and the low-pressure superheated steam are merged by the confluence device and then enter the low-pressure turbine to do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust enters the condenser to be condensed into liquid water, and the liquid water is circulating water for the steam Rankine cycle.
3. The power generation system of claim 1, wherein the steam Rankine cycle comprises a waste heat boiler, a high pressure turbine, a reheat turbine, a flow combiner, a low pressure turbine, a condenser, a low pressure water pump, a water separator, and a high pressure water pump, wherein the waste heat boiler comprises a high pressure superheater, a reheater, a high pressure evaporator, a low pressure superheater, a high pressure economizer, a low pressure evaporator, and a low pressure economizer connected by pipes in sequence from hot end to cold end, and wherein, in operation,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into two parts through the water separator, and heating one part of the preheated circulating water sequentially through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; and the other strand of the high-pressure water is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust enters the reheater to be reheated to obtain reheated steam, the reheated steam enters the reheater to do work to obtain reheated turbine exhaust after the work is done, the reheated turbine exhaust and the low-pressure superheated steam are combined by the combiner and then enter the low-pressure turbine to do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust enters the condenser to be condensed into liquid water, and the liquid water is circulating water.
4. The power generation system of claim 1, wherein the steam Rankine cycle comprises a waste heat boiler, a high pressure turbine, a flow combiner, a medium pressure turbine, a second flow combiner, a low pressure turbine, a condenser, a low pressure water pump, a water separator, a high pressure water pump, and a medium pressure pump, wherein the waste heat boiler comprises a high pressure superheater, a high pressure evaporator, a medium pressure superheater, a high pressure second stage economizer, a low pressure superheater, a medium pressure evaporator, a medium pressure economizer, a high pressure first stage economizer, a low pressure evaporator, and a low pressure economizer connected by a pipeline in sequence from hot end to cold end, and when in operation,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into three strands through the water separator, and heating one strand of circulating water sequentially flowing through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into the medium-pressure pump to be pressurized and is sequentially sent into the medium-pressure economizer, the medium-pressure evaporator and the medium-pressure superheater to be heated into medium-pressure superheated steam; and the other strand of the waste steam is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure first-stage economizer, the high-pressure second-stage economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the high-pressure turbine exhaust and the medium-pressure superheated steam are mixed and then enter the medium-pressure turbine to do work to obtain low-pressure exhaust steam, the low-pressure exhaust steam and the low-pressure superheated steam are mixed and enter the low-pressure turbine to expand and do work to obtain low-pressure turbine exhaust, the low-pressure turbine exhaust is condensed into liquid water by the condenser, and the liquid.
5. The power generation system of claim 1, wherein the steam Rankine cycle comprises a waste heat boiler, a high pressure turbine, a flow combiner, a reheat medium pressure turbine, a second flow combiner, a low pressure turbine, a condenser, a low pressure water pump, a water separator, a high pressure water pump and a medium pressure pump, wherein the waste heat boiler comprises a high pressure superheater, a reheater, a high pressure evaporator, a medium pressure superheater, a high pressure second stage economizer, a low pressure superheater, a medium pressure evaporator, a medium pressure economizer, a high pressure first stage economizer, a low pressure evaporator and a low pressure economizer which are connected by a pipeline in sequence from a hot end to a cold end, and when in operation,
pressurizing circulating water for the steam Rankine cycle through the low-pressure water pump, inputting the pressurized circulating water into the low-pressure economizer for preheating, dividing the preheated circulating water into three strands through the water separator, and heating one strand of circulating water sequentially flowing through the low-pressure evaporator and the low-pressure superheater to obtain low-pressure superheated steam; one strand of the superheated steam is sent into the medium-pressure pump to be pressurized and is sequentially sent into the medium-pressure economizer, the medium-pressure evaporator and the medium-pressure superheater to be heated into medium-pressure superheated steam; the other end is pressurized by the high-pressure water pump to obtain high-pressure water, the high-pressure water sequentially flows through the high-pressure first-stage economizer, the high-pressure second-stage economizer, the high-pressure evaporator and the high-pressure superheater and is pressurized into high-pressure superheated steam, the high-pressure superheated steam enters the high-pressure turbine to expand and do work to obtain high-pressure turbine exhaust, the exhaust gas of the high pressure turbine is mixed with the medium pressure superheated steam and then enters the reheater for reheating to obtain reheated steam, the reheated steam enters the reheated medium pressure turbine to perform expansion work to obtain medium pressure turbine exhaust, the exhaust gas of the medium pressure turbine and the low pressure superheated steam are mixed and enter the low pressure turbine to expand and do work to obtain the exhaust gas of the low pressure turbine, and the exhaust gas of the low-pressure turbine is condensed into liquid water through the condenser, and the liquid water is circulating water for the steam Rankine cycle.
6. The power generation system of claim 1, wherein LNG is first pressurized by an LNG pump to form the high-pressure LNG, and wherein the high-pressure LNG is first subjected to the CO2Condensing CO separated from the top of the flue gas water separator by a condensing heat exchanger2The predominantly flue gas then passes through the cryogenic condenser, condensing the transcritical CO2Circulating working medium CO in the cycle2And finally, the LNG is vaporized and heated to be the normal-temperature natural gas, the normal-temperature natural gas is divided into two parts through a natural gas splitter, one part of the normal-temperature natural gas is used as fuel required by oxygen-enriched combustion, and the other part of the normal-temperature natural gas is merged into a natural gas pipe network to be used as pipe-transported natural gas.
7. The power generation system of claim 1, wherein the temperature of the combustion chamber is controlled by adjusting the flow of circulating water to the combustion chamber, the flow of circulating water to the system being determined based on the maximum temperature that the equipment can withstand to ensure that the combustion temperature does not exceed the maximum allowable operating temperature of the equipment.
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| CN110296576A (en) * | 2019-06-13 | 2019-10-01 | 天津大学 | A kind of industrial smoke collecting carbonic anhydride and waste heat recycle integrated system |
| CN111365131B (en) * | 2020-02-25 | 2021-02-05 | 山东大学 | Power-cooling combined supply system driven by exhaust smoke waste heat of gas turbine and method thereof |
| CN111489083B (en) * | 2020-04-11 | 2022-03-18 | 东北电力大学 | Low-carbon economic dispatching method of electricity-gas-heat comprehensive energy system considering oxygen-enriched combustion technology |
| CN112523825B (en) * | 2020-11-23 | 2022-04-26 | 江苏科技大学 | Comprehensive cold energy utilization system and method for liquefied natural gas power ship |
| CN112832907B (en) * | 2021-03-31 | 2023-08-11 | 西安热工研究院有限公司 | Mixture transcritical cycle solar photo-thermal power generation system and method |
| CN117432493B (en) * | 2023-12-18 | 2024-03-01 | 南京天加能源科技有限公司 | Be applied to LNG gasification cold energy recovery's high-efficient ORC power generation system |
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