CN-115111577-B - Thermal power peak regulation system and method for steam ejector coupling single-tank fused salt heat storage

CN115111577BCN 115111577 BCN115111577 BCN 115111577BCN-115111577-B

Abstract

The invention discloses a thermal power peak regulation system and a thermal power peak regulation method for single-tank fused salt heat storage by coupling a steam ejector, and belongs to the technical field of thermal power peak regulation. The system comprises a superheater, a reheater, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a condenser, a low-pressure heater, a deaerator, a high-pressure heater, a steam ejector, a heat storage and exchange integrated molten salt single tank, a separator, a steam booster pump and a water supply booster pump. When the electricity demand is low or the heat demand is low, the main steam is utilized to jet the steam turbine to exhaust steam, the steam is mixed by the steam ejector and then enters a molten salt single tank, the heat of the steam is stored in high-temperature molten salt, and when the electricity demand is high or the heat demand is high, the high-temperature molten salt is used for heating boiler water supply or municipal heating backwater. The method can achieve the purposes of electric power peak regulation and thermal electrolytic coupling, and meanwhile, the defects of high investment and complex equipment of the traditional double-tank system can be effectively avoided through the use of the single molten salt tank, and the steam ejector can achieve the cascade utilization of steam energy sources, so that the purpose of energy conservation is achieved.

Inventors

ZHANG JIAJIE
WU BIN
HU YALI
MA SUXIA
LIU BIN

Assignees

太原理工大学
太原理工大学

Dates

Publication Date: 20260421
Application Date: 20220609
Priority Date: 20220609

Claims (4)

1. The thermal power peak regulation system with the steam ejector coupled with the single-tank fused salt heat storage comprises a host unit (1) and a steam ejection unit (2), wherein the host unit (1) comprises a reheater (11), a superheater (12), a high-pressure cylinder (13), a medium-pressure cylinder (14), a low-pressure cylinder (15), a condenser (16), a low-pressure heater (17), a deaerator (18) and a high-pressure heater (19), and is characterized by further comprising a fused salt heat storage unit (3), and the steam ejection unit (2) comprises a main steam regulating valve (21), a dead steam regulating valve (22) and a steam ejector (23); The molten salt heat storage unit (3) comprises a plurality of molten salt single tanks (31), separators (32), steam booster pumps (33) and water supply booster pumps (34), wherein the molten salt single tanks (31) are connected between the steam ejectors (23) and the separators (32) in parallel, the molten salt single tanks (31) are of an integrated cylindrical structure, heat storage heat exchange pipes (315), heat release heat exchange pipes (316) and partition plates (317) are arranged in the molten salt single tanks (31), and molten salt is filled in the tank bodies of the molten salt single tanks (31); The heat-storage heat exchange tube (315) is arranged at the inner side of the partition plate (317), high-temperature steam flows through the heat-storage heat exchange tube (315) for heating molten salt, the heat-storage heat exchange tube (315) is connected with the steam inlet (311) and the steam outlet (312), the heat-release heat exchange tube (316) is arranged at the outer side of the partition plate (317), water flows through the inner side of the heat-release heat exchange tube (316) for cooling the molten salt, and the heat-release heat exchange tube (316) is connected with the water side inlet (313) of the molten salt single tank (31) and the water side outlet (314) of the molten salt single tank (31); The fused salt heat storage unit is connected in parallel by utilizing a plurality of fused salt single tanks, and carries out heat storage and heat release processes by fused salt filled in the fused salt single tanks, so that the electric power peak regulation and thermoelectric decoupling of the thermal power generating unit are realized, when the electricity consumption requirement is low or the heat supply requirement is low, the full load operation of a boiler is kept, the exhaust steam of a steam turbine is ejected by main steam, and the steam is mixed by a steam ejector and then enters a plurality of fused salt single tanks, so that the heat of the steam is stored in high-temperature fused salt, and when the electricity consumption requirement is high or the heat supply requirement is high, the high-temperature fused salt is used for heating the water supply of the boiler or the municipal heating backwater; In the steam injection unit (2), a main flow inlet (231) of a steam injector (23) is connected with a main steam regulating valve (21), the main steam regulating valve (21) is connected with any main steam pipeline from a superheater (12), a secondary flow inlet (232) of the steam injector (23) is connected with a waste steam regulating valve (22), the waste steam regulating valve (22) is connected with a waste steam pipeline from a low-pressure cylinder (15), and a mixed steam outlet (233) of the steam injector (23) is connected with a steam inlet (311) of a molten salt single tank (31); The molten salt heat storage unit (3) comprises a molten salt single tank (31), a steam inlet (311) of the molten salt single tank (31), a steam outlet (312) of the molten salt single tank (31), a water side inlet (313) of the molten salt single tank (31), a water side outlet (314) of the molten salt single tank (31), a water supply pipeline of the molten salt single tank (31) and a water supply booster pump (34), a water side outlet (321) of the separator (32), a water supply booster pump (34) and a water supply pipeline of the oxygen remover (18), a steam side outlet (322) of the separator (32) and a steam booster pump (33), and a steam booster pump (33) and a steam discharge pipeline of the high-pressure cylinder (13).
2. The steam ejector coupling single-tank fused salt heat storage thermal power peak shaving system according to claim 1, wherein the shape of the partition plate (317) is matched with the shape of the fused salt single tank (31).
3. The thermal power peak shaving system of the single-tank fused salt heat storage coupled with the steam ejector according to claim 1, wherein the number of the fused salt single tanks (31) is not less than two.
4. A thermal power peak regulation method of single-tank fused salt heat storage by coupling a steam ejector, which is characterized in that the thermal power peak regulation system of single-tank fused salt heat storage by coupling the steam ejector according to any one of claims 1-3 is adopted, and the thermal power peak regulation method is applied to a pure condensing thermal power unit or a back pressure thermal power unit, and specifically comprises the following steps: In a pure condensing thermal power generating unit, the output of the unit is changed by adjusting the steam quantity of a steam turbine, so that the electric power peak regulation is realized, when the electricity consumption is low, a main steam regulating valve (21) is opened, a part of main steam flows into a main stream inlet (231) of a steam ejector (23), a dead steam regulating valve (22) is opened, a part of dead steam enters a secondary inflow port (232) of the steam ejector (23), two parts of steam entering the steam ejector (23) are mixed and then enter a plurality of fused salt single tanks (31) connected in parallel through a mixed steam outlet (233) for heat exchange, so that low-temperature fused salt in the fused salt single tanks (31) is heated into high-temperature fused salt, and the heat of the steam is stored in the high-temperature fused salt; In the back pressure type thermal power generating unit, when the thermal decoupling is needed, the thermal decoupling is realized by adjusting the flow of main steam, when the heat supply requirement is low, a main steam adjusting valve (21) is opened, a part of main steam flows into a main flow inlet (231) of a steam ejector (23), a dead steam adjusting valve (22) is opened, a part of dead steam enters a secondary inflow opening (232) of the steam ejector (23), mixed steam enters a molten salt single tank (31) for heat exchange after passing through a mixed steam outlet (233), low-temperature molten salt in the molten salt single tank (31) is heated to be high-temperature molten salt, the heat of the steam is stored in the high-temperature molten salt, when the heat supply requirement is high, the main steam adjusting valve (21) and the dead steam adjusting valve (22) are closed, the normal operation of a boiler is kept, hot user backwater (35) enters the molten salt single tank (31) for heat exchange with the high-temperature molten salt, generated hot water is sent into a hot user (36) to meet the heat supply requirement, and when the electric power peak regulation is needed, the adjusting method of the pure type thermal power generating unit is adopted, the extraction steam amount is changed, the heat extraction amount is adjusted, and the power peak regulation requirement is met.

Description

Thermal power peak regulation system and method for steam ejector coupling single-tank fused salt heat storage Technical Field The invention belongs to the technical field of thermal power peak regulation, and particularly relates to a thermal power plant peak regulation system and method for single-tank fused salt heat storage by coupling a steam ejector. Background Fused salt heat storage is a research hot spot in the energy storage technology in recent years, the fused salt heat storage is coupled with a coal electric furnace system, the load of a unit is regulated and controlled by utilizing the fused salt heat storage/release process, and the fused salt heat storage is one of effective ways for realizing flexible peak regulation of a coal electric motor unit. For example, chinese patent CN 113669715B discloses an energy storage peak shaving system suitable for reheat unit steam heating fused salt, and this system adopts the arrangement of two jars of fused salt hot jar and cold jar, stores the heat of boiler high pressure steam in high temperature fused salt, can make the output of boiler realize decoupling from turbine unit's power to satisfy the demand of electric wire netting to unit peak shaving ability. However, the traditional molten salt energy storage technology adopts a double-tank arrangement mode, the volume of each storage tank is designed to be capable of storing the capacity of the heat storage medium of the whole power station, and the actual molten salt quantity of each storage tank in the same time in actual operation cannot exceed half of the designed volume of each storage tank, so that the heat storage cost of the power station is very high, and the total investment of the molten salt storage tank occupied by a heat storage system reaches more than 20%. Meanwhile, the heat storage and heat exchange processes of molten salt in the double-tank molten salt system are carried out in the tank body and the heat exchanger separately, so that various auxiliary equipment such as a molten salt pump, a molten salt electric heater, a heat tracing system and the like are also required to be equipped, and the system is complex and has a plurality of failure points. In addition, the molten salt energy storage technology is applied to the technical scheme of thermal power peak shaving at present, and most of the molten salt energy storage technology directly utilizes high-temperature and high-pressure steam of a power plant to heat molten salt. For example, chinese patent CN 108426238A discloses a fused salt heat storage and supply system of a thermal power plant which uses main steam to heat fused salt through a fused salt heat exchanger. However, the boiler steam of the thermal power plant is usually high-parameter steam, and the conventional shell-and-tube heat exchanger is limited by high-temperature high-pressure heat exchange media, so that supercritical heat exchange is very difficult. If the parameters of the boiler steam are reduced and then enter the heat exchanger, for example, a temperature and pressure reducing valve is adopted, high-grade steam generated by the boiler is wasted, and energy is wasted. Disclosure of Invention Based on the background, the invention discloses a thermal power peak regulation system and a thermal power peak regulation method for single-tank fused salt heat storage by coupling a steam ejector. When electricity demand low valley or heat supply demand are low, keep boiler full load operation, utilize main steam to draw steam turbine exhaust steam, get into a plurality of fused salt single pot after mixing through the steam ejector, store the heat of steam in high temperature fused salt, when electricity demand peak or heat supply demand are high, be used for heating boiler feedwater or municipal heating return water with high temperature fused salt. The invention can be applied to a pure condensing thermal power unit or a back pressure thermal power unit. The technical problems solved by the invention are realized by the following technical scheme: The thermal power peak shaving system comprises a host unit and a steam injection unit, wherein the host unit comprises a reheater, a superheater, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a condenser, a low-pressure heater, a deaerator and a high-pressure heater, the thermal power peak shaving system further comprises a molten salt heat storage unit, the steam injection unit comprises a main steam regulating valve, a dead steam regulating valve and a steam injector, the molten salt heat storage unit comprises a plurality of molten salt single tanks, a separator, a steam booster pump and a water supply booster pump, and the molten salt single tanks are connected between the steam injector and the separator in parallel. In the steam injection unit, a main flow inlet of a steam injector is connected with a main steam regulating valve, the main steam regulating valve is connected wi