CN105823077A - Thermal power plant medium-low temperature flue gas heat energy gradient utilization system and method - Google Patents
Thermal power plant medium-low temperature flue gas heat energy gradient utilization system and method Download PDFInfo
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- CN105823077A CN105823077A CN201610164473.4A CN201610164473A CN105823077A CN 105823077 A CN105823077 A CN 105823077A CN 201610164473 A CN201610164473 A CN 201610164473A CN 105823077 A CN105823077 A CN 105823077A
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- Prior art keywords
- brayton cycle
- flue gas
- power plant
- heater
- air
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L15/00—Heating of air supplied for combustion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G1/00—Hot gas positive-displacement engine plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G2250/00—Special cycles or special engines
- F02G2250/03—Brayton cycles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Air Supply (AREA)
- Engine Equipment That Uses Special Cycles (AREA)
Abstract
The invention provides a thermal power plant medium-low temperature flue gas heat energy gradient utilization system and method. According to the thermal power plant medium-low temperature flue gas heat energy gradient utilization system, a Brayton cycle is arranged at thermal power plant boiler tail flues in a coupled mode, the thermal power plant boiler tail flues are separated flues, that is, two flues are adopted, one of the flues communicates with a flue gas inlet of an air pre-heater, and the other flue communicates with a flue gas inlet of a Brayton cycle heater; a working medium outlet of the Brayton cycle heater communicates with an inlet of a turbine; an outlet of the turbine communicates with a working medium inlet of a Brayton cycle cooler; a working medium outlet of the Brayton cycle cooler communicates with a working medium inlet of the Brayton cycle heater through an air compressor; a hot air outlet of the Brayton cycle cooler communicates with an air inlet of the air pre-heater; and an air outlet of the air pre-heater is connected with a boiler burner. The invention further discloses the flue gas heat energy gradient utilization method, the heat exchanging process of thermal power plant medium-low temperature flue gas can be optimized, the irreversible loss of the air pre-heater is reduced, accordingly, the efficiency of a whole thermal power plant is improved, the temperature of air entering the air pre-heater is increased at the same time, and safe operation of the air pre-heater is facilitated.
Description
Technical field
The present invention relates to thermal power plant's heat energy utilization field, be specifically related to a kind of low-temperature flue gas heat energy stepped utilization system and method in thermal power plant.
Background technology
Thermal power generation is the main body of China's power generation, and along with going deep into of China's energy-saving and emission-reduction work, smoke discharging residual heat utilizes the attention gradually causing scholars.In the air preheater of thermal power plant, owing to boiler exhaust gas unit temperature drop thermal discharge is more than boiler air-supply unit temperature drop caloric receptivity, cause air preheater exhanst gas outlet side (air inlet side) heat transfer temperature difference big, reach more than 100 DEG C, thereby result in air preheater irreversible loss bigger.
Summary of the invention
For the problem overcoming above-mentioned prior art to exist, it is an object of the invention to provide a kind of low-temperature flue gas heat energy stepped utilization system and method in thermal power plant, the present invention can optimize the heat exchange process of low-temperature flue gas in thermal power plant, reduce air preheater irreversible loss, thus improve whole thermal power plant efficiency, improve entrance air preheater air themperature favourable to the safe operation of air preheater simultaneously.
In order to achieve the above object, the present invention is by the following technical solutions:
Low-temperature flue gas heat energy stepped utilization system in a kind of thermal power plant, in power plant boiler back-end ductwork coupled arrangement Brayton cycle, and power plant boiler back-end ductwork uses and separates flue i.e. two-way flue, one road flue connection air preheater 1 smoke inlet, another road flue connection Brayton cycle heater 2 smoke inlet, described Brayton cycle heater 2 sender property outlet connection turbine 3 entrance, turbine 3 outlet Brayton cycle cooler 4 working medium entrance, Brayton cycle cooler 4 sender property outlet connects Brayton cycle heater 2 working medium entrance by compressor 5；Described Brayton cycle cooler 4 cool air inlet connection atmospheric environment, hot air outlet connection air preheater 1 air intake, air preheater 1 air outlet slit connects boiler-burner；Described air preheater 1 all connects flue gas processing device with the exhanst gas outlet of Brayton cycle heater 2.
Brayton cycle working medium in described Brayton cycle heater 2 and Brayton cycle cooler 4 is supercritical CO2。
This system generated energy is used for Service Power in Thermal Power Plant, to reduce Service Power in Thermal Power Plant rate.
The Application way of low-temperature flue gas heat energy stepped utilization system in thermal power plant described above, boiler smoke is divided into two parts before entering air preheater 1, part of smoke enters air preheater 1, another part flue gas enters Brayton cycle heater 2 and heats Brayton cycle working medium, Brayton cycle working medium enters decrease temperature and pressure in turbine 3 and externally does work after heating up in Brayton cycle heater 2, then enter preboiler air-supply in Brayton cycle cooler 4, and self cooling, Brayton cycle working medium after cooling enters in Brayton cycle heater 2 after compressor 5 boosts and completes Brayton cycle；After boiler combustion required air first sends into Brayton cycle cooler 4 preheating, it is re-fed into air preheater 1, is ultimately delivered to boiler-burner.
Distributing into the flue gas in Brayton cycle heater 2 and accounting for the quality share of total flue gas is 10%～35%.
The most relatively, the present invention possesses following advantage:
1. present invention reduces the irreversible loss of air preheater, Brayton cycle is utilized to achieve effective utilization of smoke heat energy, net coal consumption rate 1.5～2.5g/kWh can be reduced, use can be coupled further with low-level (stack-gas) economizer simultaneously, make power station power supply coa consumption rate reduce by 3～4.5g/kWh；
2. the present invention improves air preheater entrance pathogenic wind-warm, can effectively reduce air preheater corrosion, improve boiler air preheater operational reliability.
Accompanying drawing explanation
Fig. 1 is low-temperature flue gas heat energy stepped utilization system figure in thermal power plant of the present invention.
Fig. 2 is preferable Brayton cycle figure.
Detailed description of the invention
With detailed description of the invention, the present invention is described in further detail below in conjunction with the accompanying drawings.
As shown in Figure 1, low-temperature flue gas heat energy stepped utilization system in one thermal power plant of the present invention, in power plant boiler back-end ductwork coupled arrangement Brayton cycle, and power plant boiler back-end ductwork uses and separates flue i.e. two-way flue, one road flue connection air preheater 1 smoke inlet, another road flue connection Brayton cycle heater 2 smoke inlet, described Brayton cycle heater 2 sender property outlet connection turbine 3 entrance, turbine 3 outlet Brayton cycle cooler 4 working medium entrance, Brayton cycle cooler 4 sender property outlet connects Brayton cycle heater 2 working medium entrance by compressor 5；Described Brayton cycle cooler 4 cool air inlet connection atmospheric environment, hot air outlet connection air preheater 1 air intake, air preheater 1 air outlet slit connects boiler-burner；Described air preheater 1 all connects flue gas processing device with the exhanst gas outlet of Brayton cycle heater 2.
As the preferred embodiment of the present invention, the Brayton cycle working medium in described Brayton cycle heater 2 and Brayton cycle cooler 4 is supercritical CO2。
Present system generated energy is used for Service Power in Thermal Power Plant, to reduce Service Power in Thermal Power Plant rate.
The Application way of low-temperature flue gas heat energy stepped utilization system in thermal power plant of the present invention, boiler smoke is divided into two parts before entering air preheater 1, part of smoke enters air preheater 1, another part flue gas enters Brayton cycle heater 2 and heats Brayton cycle working medium, Brayton cycle working medium enters decrease temperature and pressure in turbine 3 and externally does work after heating up in Brayton cycle heater 2, then enter preboiler air-supply in Brayton cycle cooler 4, and self cooling, Brayton cycle working medium after cooling enters in Brayton cycle heater 2 after compressor 5 boosts and completes Brayton cycle；After boiler combustion required air first sends into Brayton cycle cooler 4 preheating, it is re-fed into air preheater 1, is ultimately delivered to boiler-burner.
As the preferred embodiment of the present invention, distributing into the flue gas in Brayton cycle heater 2 and accounting for the quality share of total flue gas is 10%～35%.
Operation principle the following detailed description of the present invention:
In the air preheater of thermal power plant, there is following relation:
mfcpf＞ maircpair
In formula: mf、mairIt is respectively flue gas, air mass flow, kg/s；cpf、cpairIt is respectively flue gas air specific heat capacity, kJ/ (kg K).
Therefore, boiler exhaust gas unit temperature drop thermal discharge is more than boiler air-supply unit temperature drop caloric receptivity, in air preheater, heat smoke exotherm mates poor with cold air endothermic curve, air preheater exhanst gas outlet side (air inlet side) heat transfer temperature difference is big, reach more than 100 DEG C, thereby result in air preheater irreversible loss bigger.
To this end, the present invention proposes to use separates flue, entrance air preheater flue gas shunting partial fume is driven Brayton cycle as thermal source so that:
mfcpf≈maircpair
Thus reduce the irreversible loss of flue gas in air preheater, air heat-exchange.
Meanwhile, utilize Brayton cycle cooler that the flue gas before entering air preheater is preheated, on the one hand supplement the flue gas heat deficiency that shunting flue gas brings, on the one hand can effectively reduce the corrosion risk of air preheater.Preferable Brayton cycle schematic diagram as in figure 2 it is shown, wherein 1-2 be adiabatic compression process, 2-3 is constant-pressure heating process, and 3-4 is adiabatic expansion, and 4-1 is level pressure exothermic process.
Brayton cycle isobaric heat absorption, exotherm mate preferably with flue gas heat release, air endothermic curve, and irreversibility is low.Brayton cycle working medium can choose the CO under supercriticality2Deng.
Its work process is: in conventional thermal power plant, and boiler smoke all sends into air preheater.
In thermal power plant of the present invention, low-temperature flue gas heat energy stepped utilization system uses and separates flue, and partial fume is sent into air preheater 1, and partial fume sends into Brayton cycle heater 2.Brayton cycle working medium is absorbed heat in thunder pauses recirculation heater 2, then enter expansion work in turbine 3, enter Brayton cycle cooler 4 afterwards the air entering air preheater 1 is heated, and self cooling, the working medium after cooling is sent in Brayton cycle heater 2 after sending into compressor 5 boosting and is completed Brayton cycle.Boiler required air sends into boiler-burner after Brayton cycle cooler 4, air preheater 1 two-step heating.
Claims (5)
1. low-temperature flue gas heat energy stepped utilization system in a thermal power plant, it is characterized in that: in power plant boiler back-end ductwork coupled arrangement Brayton cycle, and power plant boiler back-end ductwork uses and separates flue i.e. two-way flue, one road flue connection air preheater (1) smoke inlet, another road flue connection Brayton cycle heater (2) smoke inlet, described Brayton cycle heater (2) sender property outlet connection turbine (3) entrance, turbine (3) outlet Brayton cycle cooler (4) working medium entrance, Brayton cycle cooler (4) sender property outlet connects Brayton cycle heater (2) working medium entrance by compressor (5)；Described Brayton cycle cooler (4) cool air inlet connection atmospheric environment, hot air outlet connection air preheater (1) air intake, air preheater (1) air outlet slit connects boiler-burner；Described air preheater (1) all connects flue gas processing device with the exhanst gas outlet of Brayton cycle heater (2).
Low-temperature flue gas heat energy stepped utilization system in thermal power plant the most according to claim 1, it is characterised in that: the Brayton cycle working medium in described Brayton cycle heater (2) and Brayton cycle cooler (4) is supercritical CO2。
Low-temperature flue gas heat energy stepped utilization system in thermal power plant the most according to claim 1, it is characterised in that: this system generated energy is used for Service Power in Thermal Power Plant, to reduce Service Power in Thermal Power Plant rate.
4. the Application way of low-temperature flue gas heat energy stepped utilization system in thermal power plant described in claim 1, it is characterized in that: boiler smoke front is divided into two parts entering air preheater (1), part of smoke enters air preheater (1), another part flue gas enters Brayton cycle heater (2) and heats Brayton cycle working medium, Brayton cycle working medium enters decrease temperature and pressure in turbine (3) and externally does work after heating up in Brayton cycle heater (2), then enter preboiler air-supply in Brayton cycle cooler (4), and self cooling, Brayton cycle working medium after cooling enters in Brayton cycle heater (2) after compressor (5) boosts and completes Brayton cycle；After boiler combustion required air first sends into Brayton cycle cooler (4) preheating, it is re-fed into air preheater (1), is ultimately delivered to boiler-burner.
Method the most according to claim 4, it is characterised in that: distributing into the flue gas in Brayton cycle heater (2) and accounting for the quality share of total flue gas is 10%～35%.
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| CN201610164473.4A CN105823077B (en) | 2016-03-22 | 2016-03-22 | Low-temperature flue gas heat energy stepped utilization system and method in a kind of thermal power plant |
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| CN201610164473.4A CN105823077B (en) | 2016-03-22 | 2016-03-22 | Low-temperature flue gas heat energy stepped utilization system and method in a kind of thermal power plant |
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| CN105823077B CN105823077B (en) | 2019-01-08 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106242019A (en) * | 2016-09-14 | 2016-12-21 | 西安热工研究院有限公司 | The coupled system that supercritical carbon dioxide Brayton cycle generating waste water processes |
| CN106593556A (en) * | 2017-01-24 | 2017-04-26 | 上海发电设备成套设计研究院 | Biomass burning power generation system and method employing supercritical carbon dioxide cycle |
| CN108613170A (en) * | 2018-03-14 | 2018-10-02 | 西安交通大学 | A kind of supercritical carbon dioxide coal generating system and operation method |
| CN108825317A (en) * | 2018-06-29 | 2018-11-16 | 东方电气集团东方汽轮机有限公司 | A kind of heat integration utilizes system |
| CN109026226A (en) * | 2018-06-29 | 2018-12-18 | 东方电气集团东方汽轮机有限公司 | A kind of association system that heat integration utilizes |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106242019A (en) * | 2016-09-14 | 2016-12-21 | 西安热工研究院有限公司 | The coupled system that supercritical carbon dioxide Brayton cycle generating waste water processes |
| CN106593556A (en) * | 2017-01-24 | 2017-04-26 | 上海发电设备成套设计研究院 | Biomass burning power generation system and method employing supercritical carbon dioxide cycle |
| CN106593556B (en) * | 2017-01-24 | 2018-12-11 | 上海发电设备成套设计研究院 | The generating power with biomass combustion system and method recycled using supercritical carbon dioxide |
| CN108613170A (en) * | 2018-03-14 | 2018-10-02 | 西安交通大学 | A kind of supercritical carbon dioxide coal generating system and operation method |
| CN108825317A (en) * | 2018-06-29 | 2018-11-16 | 东方电气集团东方汽轮机有限公司 | A kind of heat integration utilizes system |
| CN109026226A (en) * | 2018-06-29 | 2018-12-18 | 东方电气集团东方汽轮机有限公司 | A kind of association system that heat integration utilizes |
| CN108825317B (en) * | 2018-06-29 | 2021-04-13 | 东方电气集团东方汽轮机有限公司 | Heat comprehensive utilization system |
| CN109026226B (en) * | 2018-06-29 | 2021-07-20 | 东方电气集团东方汽轮机有限公司 | Combined system for comprehensively utilizing heat |
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| CN105823077B (en) | 2019-01-08 |
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