CN109237587B - Low-vacuum heat supply system coupled with large-temperature-difference heat pump and operation method - Google Patents
Low-vacuum heat supply system coupled with large-temperature-difference heat pump and operation method Download PDFInfo
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- 238000010438 heat treatment Methods 0.000 claims abstract description 73
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 claims abstract description 42
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D3/00—Hot-water central heating systems
- F24D3/18—Hot-water central heating systems using heat pumps
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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
- F01K17/00—Using steam or condensate extracted or exhausted from steam engine plant
- F01K17/02—Using steam or condensate extracted or exhausted from steam engine plant for heating purposes, e.g. industrial, domestic
- F01K17/025—Using steam or condensate extracted or exhausted from steam engine plant for heating purposes, e.g. industrial, domestic in combination with at least one gas turbine, e.g. a combustion gas turbine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D3/00—Hot-water central heating systems
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Abstract
The invention relates to a low vacuum heating system coupled with a large-temperature-difference heat pump and an operation method thereof, belonging to the technical field of cogeneration energy conservation. The invention comprises a steam turbine, a condenser, a cooling tower, a heat supply network heat exchanger, a drainage heat exchanger and a secondary heat exchange station, wherein the secondary heat exchange station comprises a large-temperature-difference heat pump and a water-water heat exchanger, the heat supply network heat exchanger, the large-temperature-difference heat pump, the water-water heat exchanger, the drainage heat exchanger and the condenser are sequentially arranged on a loop of a primary network water supply and return pipe, valves and bypasses are arranged at inlets and outlets of different devices, the drainage heat exchanger and the condenser are connected in series and parallel through the switch of the valves on the primary network side, and the large-temperature-difference heat pump and the water-water heat exchanger are connected in series and parallel through the switch of the valves on the secondary network side in the secondary heat exchange station. The invention reasonably designs the coupling system based on the principle of energy cascade utilization, realizes cascade heating of the heat supply network water, reduces irreversible loss in the heat exchange process, and has higher practical application value.
Description
Technical Field
The invention relates to a low vacuum heating system coupled with a large-temperature-difference heat pump and an operation method thereof, belonging to the technical field of cogeneration energy conservation.
Background
With the continuous deep treatment of haze in China, central heat supply is developed, and the shutdown of a small heat supply boiler becomes increasingly common knowledge of governments and folk. The stable heat source is needed for developing urban central heating, so that the heat supply transformation or the heat supply capacity improvement is carried out on the existing pure condensing unit or heat supply unit, and the heat supply potential is excavated and released, thereby becoming an effective method. After the steam exhausted into the low-pressure cylinder by the steam turbine of the thermal power plant works, the steam enters the condenser to form condensation heat, the condensation heat generally accounts for more than 30% of the total input heat of primary energy, and the partial heat is generally directly exhausted into the atmosphere through a water cooling tower or an air cooling island to form huge cold end loss. This part of the heat is characterized by concentration but low grade, and it has long been difficult to find a good direct utilization method. In addition, with the development of national economy and society, the acceleration of urbanization process and the improvement of the living standard of people, the heat supply of residents is more and more emphasized, and the central heat supply area of the national city in 2016 reaches 73.9 hundred million square meters; in order to meet the heat supply demands of residents, how to improve the conveying capacity of a pipe network on the basis of the existing heat supply pipe network is urgent.
At present, the effective technical means for improving the conveying capacity of a pipe network is a large-temperature-difference heat supply technology, and the existing technical means mainly comprise the following two steps: the patent with the application number 201110195467.2 is a heating system for improving the heat supply capacity of a central heating pipe network by utilizing a heat pump technology, and is mainly characterized in that (1) an absorption heat pump unit is arranged at a heat exchange station close to a heat source, and secondary network water close to the heat source is heated by utilizing the waste heat of primary network water supply driving heat pump backwater primary network backwater to supply heat to a heat user close to the heat source; (2) The method comprises the steps of obtaining cooled primary net water after driving a heat pump, and conveying the cooled primary net water to a conventional heat exchange station to heat secondary net water far away from a heat source so as to supply heat for a heat user far away from the heat source; (3) The heat exchange is performed firstly through the secondary network water and the primary network backwater, so that the temperature of the primary network backwater is reduced, the cooled primary network backwater is used as a low-temperature heat source to enter the absorption heat pump, the temperature of the primary network backwater is further reduced, and therefore the waste heat of the primary network backwater is fully recovered, and the large-temperature-difference heat supply is realized. Secondly, the patent with application number 20080101065. X is a large-temperature-difference central heating system, which is mainly characterized in that (1) the system is arranged on the heat source side, and the low-temperature circulating water waste heat of the thermal power plant is recovered by utilizing a steam type absorption heat pump, so that the cold end loss of the thermal power plant is reduced; (2) On the secondary network side, the hot water absorption heat pump and the water-water heat exchanger are connected in series, and the secondary network water supply temperature cannot be adjusted by changing the secondary network water flow entering the hot water absorption heat pump or the water-water heat exchanger.
The defects of the two technical measures are as follows: (1) An absorption heat pump unit is arranged close to a heat source to realize large-temperature-difference heat supply, and a heat exchange station far away from the heat source cannot effectively adopt the large-temperature-difference heat supply; (2) The mode of recycling the waste heat of the circulating water of the thermal power plant by utilizing the steam absorption heat pump has larger investment and is far higher than the mode of directly supplying heat in low vacuum, (3) the hot water absorption heat pump and the water-water heat exchanger are connected in series at the secondary network side, and the water supply temperature of the secondary network cannot be adjusted by adjusting the flow. The invention mainly aims at the defects of the three techniques, and creates a low-vacuum heat supply system coupled with a large-temperature-difference heat pump and an operation method.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a low-vacuum heat supply system which is reasonable in design and reliable in performance and realizes coupling of a large-temperature-difference heat pump and an operation method.
The invention solves the problems by adopting the following technical scheme: a low vacuum heating system of coupling large temperature difference heat pump, its characterized in that: the device comprises a steam turbine, a condenser, a cooling tower, a heat supply network heat exchanger, a drainage heat exchanger and a secondary heat exchange station; the secondary heat exchange station comprises a large-temperature-difference heat pump and a water-water heat exchanger; the steam outlet of the heat supply network heat exchanger is connected with the heating steam outlet of the steam turbine through a heating steam extraction pipe, the first valve is arranged on the heating steam extraction pipe, the drainage outlet of the heat supply network heat exchanger is connected with the drainage inlet of the drainage heat exchanger through a first drainage pipe, and the drainage outlet of the drainage heat exchanger is connected with a second drainage pipe; one end of a primary net return pipe is connected with a primary net water outlet of the water-water heat exchanger, the other end of the primary net return pipe is connected with a circulating water outlet of a third valve, and a large-temperature-difference heat pump and a hydrophobic heat exchanger are sequentially arranged on the primary net return pipe along the water flowing direction; one end of a primary net water supply pipe is connected with a primary net water inlet of the water-water heat exchanger, the other end of the primary net water supply pipe is connected with a circulating water inlet of the second valve, and a heat supply net heat exchanger and a large-temperature-difference heat pump are sequentially arranged on the primary net water supply pipe along the water flowing direction; the secondary net return water pipe is connected with the water heat exchanger and the large-temperature-difference heat pump through a secondary net return water A branch pipe and a secondary net return water B branch pipe respectively, a seventeenth valve and an eighteenth valve are respectively arranged on the secondary net return water A branch pipe and the secondary net return water B branch pipe, a secondary net water outlet of the water heat exchanger is connected with a heat supply net water outlet of the eighteenth valve and a secondary net water supply pipe through the secondary net water supply A branch pipe and the secondary net water supply B branch pipe respectively, a sixteenth valve and a nineteenth valve are respectively arranged on the secondary net water supply A branch pipe and the secondary net water supply B branch pipe, and a secondary net water inlet of the secondary net water supply pipe is connected with the large-temperature-difference heat pump.
Further, a first water return bypass is arranged on the water return side of the primary net of the hydrophobic heat exchanger, and an eighth valve, a seventh valve and a ninth valve are respectively arranged on the water return inlet of the primary net, the water return outlet of the primary net and the first water return bypass of the hydrophobic heat exchanger; the drain side of the drain heat exchanger is provided with a first drain bypass, and a twenty-second valve and a twenty-first valve are respectively arranged on the drain inlet and the first drain bypass of the drain heat exchanger.
Further, a primary net backwater inlet of the seventh valve is connected with a circulating water inlet of the second valve through a third water supply bypass, and a twentieth valve is arranged on the third water supply bypass.
Furthermore, a second backwater bypass is arranged on the backwater side of the primary network of the large-temperature-difference heat pump, and a fourteenth valve, a thirteenth valve and a fifteenth valve are respectively arranged on the backwater inlet, the backwater outlet and the second backwater bypass of the primary network of the large-temperature-difference heat pump.
Furthermore, a first water supply bypass is arranged on the primary network water supply side of the heat supply network heat exchanger, and a fourth valve, a fifth valve and a sixth valve are respectively arranged on the primary network water supply inlet, the primary network water supply outlet and the first water supply bypass of the heat supply network heat exchanger.
Furthermore, a second water supply bypass is arranged on the water supply side of the primary network of the large-temperature-difference heat pump, and a tenth valve, an eleventh valve and a twelfth valve are respectively arranged on the water supply inlet of the primary network, the water supply outlet of the primary network and the second water supply bypass of the large-temperature-difference heat pump.
Furthermore, the large-temperature-difference heat pump utilizes primary net water supply as a driving heat source, primary net backwater is used as a low-temperature heat source, and waste heat of the primary net backwater is recovered to heat secondary net water, so that large-temperature-difference heat supply is realized.
Furthermore, after the heat supply network drainage of the heat supply network heat exchanger is subjected to secondary heat exchange by the drainage heat exchanger, the temperature is further reduced, and the heat supply network drainage after the secondary heat exchange and temperature reduction is conveyed to a low-pressure heat recovery system of the steam turbine through a second drainage pipe.
The operation method of the low vacuum heat supply system coupled with the large-temperature-difference heat pump is as follows:
when the heating system is not in heating season, only the second valve and the third valve are opened, the steam turbine runs under the pure condensation working condition, the circulating water is heated in the condenser and then is conveyed to the cooling tower for cooling, and the cooled circulating water returns to the condenser for heating;
when the heating season is in the initial stage and the final stage, only the sixth valve, the ninth valve, the twelfth valve, the fifteenth valve, the seventeenth valve and the nineteenth valve are opened, and the steam turbine runs under the back pressure working condition; the primary net water is heated in the condenser and then is conveyed to a water-water heat exchanger of the secondary heat exchange station to heat the secondary net water, and then the heated secondary net water is conveyed to a heat user to supply heat;
during a high-cold period in a heating season, only a first valve, a fourth valve, a fifth valve, a seventh valve, an eighth valve, a tenth valve, an eleventh valve, a thirteenth valve, a fourteenth valve, a sixteenth valve, a seventeenth valve and a twenty second valve are opened, the drainage heat exchanger, the condenser and the heat supply network heat exchanger are connected in series, the steam turbine operates under a back pressure working condition, the large-temperature-difference heat pump is put into operation, the large-temperature-difference heat pump and the water-water heat exchanger are connected in series, primary network backwater is heated in the drainage heat exchanger, then enters the condenser for secondary heating, then enters the heat supply network heat exchanger for tertiary heating, and finally is conveyed to a secondary heat exchange station through a primary network water supply pipe; the primary network water supply is firstly used as a driving heat source of the large-temperature difference heat pump to carry out primary cooling, then enters a water-water heat exchanger to carry out secondary cooling, is used as a low-temperature heat source to enter the large-temperature difference heat pump to carry out tertiary cooling, and finally returns to the thermal power plant through a primary network return pipe; the secondary net backwater conveyed by the secondary net backwater pipe is firstly subjected to primary heating in a water-water heat exchanger, then enters a large-temperature difference heat pump for secondary heating, and is conveyed to a heat user for heat supply through a secondary net water supply pipe.
Furthermore, in the high and cold period of the heating season, the water drainage flow and the primary network backwater flow entering the water drainage heat exchanger can be regulated by opening and regulating the opening of the ninth valve and the twenty-first valve and regulating the opening of the eighth valve and the twenty-second valve, so that the primary network backwater temperature entering the condenser can be regulated;
when the temperature of primary network backwater is higher than a specified value in a high-cold period of a heating season, closing a seventh valve, opening a ninth valve and a twentieth valve at the moment, enabling the drainage heat exchanger and the condenser to be connected in parallel, then connecting the drainage heat exchanger and the condenser in series, enabling the primary network backwater to enter the heat exchanger for secondary heating after primary heating is carried out on the drainage heat exchanger and the condenser respectively;
during the high and cold period of heating season, the opening of the seventeenth valve, the eighteenth valve, the sixteenth valve and the nineteenth valve is opened and regulated to regulate the water return flow of the secondary network entering the large-temperature-difference heat pump and the water-water heat exchanger, so as to regulate the temperature of the water supply of the secondary network;
when the water supply temperature of the secondary network required by a heat user is lower than a specified value in the high-cold period of a heating season, closing a sixteenth valve, opening an eighteenth valve and a nineteenth valve, enabling the large-temperature-difference heat pump and the water-water heat exchanger to be connected in parallel, enabling two paths of water returning of the secondary network to enter the large-temperature-difference heat pump and the water-water heat exchanger for heating at the same time, and conveying heated secondary network water to the heat user for heat supply through a secondary network water supply pipe after mixing; at the moment, the water flow rate of the secondary network entering the large-temperature-difference heat pump and the water-water heat exchanger is changed by adjusting the opening degrees of the seventeenth valve and the eighteenth valve, so that the temperature of the water supply of the secondary network is adjusted.
Compared with the prior art, the invention has the following advantages and effects: (1) The invention has reasonable design, simple structure and reliable performance, and the large-temperature difference heat pump is coupled in the low-vacuum heat supply system, so that the initial engineering investment is reduced, the effective recovery of low-temperature waste heat of a thermal power plant is realized, and the conveying capacity of a heat supply pipe network is improved; (2) According to the invention, the drainage heat exchanger is connected with the condenser in series and in parallel in a switching way, so that the return water temperature of a primary network entering the condenser is effectively controlled, and the heat transfer performance of the condenser is improved; (3) According to the invention, the secondary network side large-temperature difference heat pump is connected with the water-water heat exchanger in series and in parallel in a switching manner, so that the adjustment of the water supply temperature of the secondary network is realized, and the heat supply quality of a heat user is improved; (4) The invention reasonably designs the coupling system based on the principle of energy cascade utilization, realizes cascade heating of primary and secondary network water, effectively reduces irreversible loss in the heat exchange process, and has higher practical application value.
Drawings
Fig. 1 is a schematic diagram of a low vacuum heating system coupled with a large temperature difference heat pump in this embodiment.
Fig. 2 is a schematic diagram of the low vacuum heating system in this embodiment during the operation of the back pressure condition at the beginning and end of the heating season.
Fig. 3 is a schematic structural diagram of a primary-network-side hydrophobic heat exchanger connected in parallel with a condenser in the present embodiment.
Fig. 4 is a schematic structural diagram of a primary-network-side hydrophobic heat exchanger connected in series with a condenser in this embodiment.
Fig. 5 is a schematic structural diagram of a secondary network side large temperature difference heat pump connected in parallel with a water-water heat exchanger in the present embodiment.
Fig. 6 is a schematic structural diagram of a secondary-network-side large-temperature-difference heat pump connected in series with a water-water heat exchanger in the present embodiment.
Detailed Description
The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and not limited to the following examples.
Examples
Referring to fig. 1, the low vacuum heating system of the coupled large temperature difference heat pump in the present embodiment includes: steam turbine 1, condenser 2, cooling tower 3, heat supply network heat exchanger 4, drainage heat exchanger 5 and secondary heat exchange station 6, secondary heat exchange station 6 includes: a large temperature difference heat pump 61 and a water-water heat exchanger 62; the steam outlet of the steam turbine 1 is connected with the condenser 2, the condenser 2 is connected with the cooling tower 3 through a circulating water supply pipe 12 and a circulating water return pipe 13, a second valve 32 and a third valve 33 are respectively arranged on the circulating water supply pipe 12 and the circulating water return pipe 13, the steam inlet of the heat supply network heat exchanger 4 is connected with the heating steam outlet of the steam turbine 1 through a heating steam extraction pipe 11, a first valve 31 is arranged on the heating steam extraction pipe 11, the water drain outlet of the heat supply network heat exchanger 4 is connected with the water drain inlet of the water drain heat exchanger 5 through a first water drain pipe 20, the water drain outlet of the water drain heat exchanger 5 is connected with a second water drain pipe 21, a first water drain bypass 29 is arranged on the water drain side of the water drain heat exchanger 5, a twenty second valve 52 and a twenty first valve 51 are respectively arranged on the water drain inlet of the water drain heat exchanger 5 and the first water drain bypass 29, one end of the primary network water return pipe 14 is connected with the primary network water outlet of the water drain heat exchanger 62, the other end of the primary network water return pipe 14 is connected with a circulating water outlet of the third valve 33, a large-temperature-difference heat pump 61 and a hydrophobic heat exchanger 5 are sequentially arranged on the primary network water return pipe 14 along the water flowing direction, a primary network water return side of the hydrophobic heat exchanger 5 is provided with a first water return bypass 15, an eighth valve 38, a seventh valve 37 and a ninth valve 39 are respectively arranged on a primary network water return inlet, a primary network water return outlet and the first water return bypass 15 of the hydrophobic heat exchanger 5, a primary network water return inlet of the seventh valve 37 is connected with a circulating water inlet of the second valve 32 through a third water supply bypass 28, a twentieth valve 50 is arranged on the third water supply bypass 28, a primary network water return side of the large-temperature-difference heat pump 61 is provided with a second water return bypass 16, and a primary network water return inlet of the large-temperature-difference heat pump 61 is provided with a third water return bypass 16, A fourteenth valve 44, a thirteenth valve 43 and a fifteenth valve 45 are respectively installed on the primary net backwater outlet and the second backwater bypass 16, one end of the primary net water supply pipe 17 is connected with the primary net water inlet of the water heat exchanger 62, the other end of the primary net water supply pipe 17 is connected with the circulating water inlet of the second valve 32, a heat supply net heat exchanger 4 and a large temperature difference heat pump 61 are sequentially installed on the primary net water supply pipe 17 along the water flowing direction, a first water supply bypass 18 is arranged on the primary net water supply side of the heat supply net heat exchanger 4, a fourth valve 34, a fifth valve 35 and a sixth valve 36 are respectively installed on the primary net water supply inlet, the primary net water supply outlet and the first water supply bypass 18 of the heat supply net heat exchanger 4, a second water supply bypass 19 is arranged on the primary net water supply side of the large temperature difference heat pump 61, a tenth valve 40, an eleventh valve 41 and a twelfth valve 42 are respectively installed on the primary net water supply inlet, the primary net water supply outlet and the second water supply bypass 19, a second water return pipe 22 is respectively connected with the heat pump 27 a water supply pipe 27 and a water supply pipe 27 through a secondary net branch pipe 23 and a secondary net branch pipe 24 and a water supply pipe 26B, a water supply pipe 26 is respectively connected with the heat pump 27 a water supply pipe 26A and a water supply pipe 26, a water supply pipe 26 is respectively installed on the secondary net water supply pipe 27 and a water supply pipe 26B branch pipe 26B and a second water supply pipe 25, and a water supply pipe 26 is respectively connected with the second water supply pipe 27 is connected with the secondary net water supply pipe 26, and a water supply pipe 26B and a second water supply pipe is connected with the water supply pipe 26, and a water supply pipeline is respectively.
In the present embodiment, the large-temperature-difference heat pump 61 uses the primary-net water supply as a driving heat source, uses the primary-net backwater as a low-temperature heat source, and recovers the waste heat of the primary-net backwater to heat the secondary-net water, thereby realizing large-temperature-difference heat supply.
In this embodiment, after the heat supply network drainage of the heat supply network heat exchanger 4 passes through the drainage heat exchanger 5 for secondary heat exchange, the temperature is further reduced, and the heat supply network drainage after the secondary heat exchange and temperature reduction is conveyed to the low-pressure heat recovery system of the steam turbine 1 through the second drainage pipe 21.
Referring to fig. 2 to 6, the operation method of the low vacuum heat supply system coupled with the large temperature difference heat pump is as follows:
when the heating season is not performed, only the second valve 32 and the third valve 33 are opened, the steam turbine 1 runs under the pure condensation working condition, the circulating water is heated in the condenser 2 and then is conveyed to the cooling tower 3 for cooling, and the cooled circulating water is returned to the condenser 2 for heating;
during the initial stage and the final stage of the heating season, only the sixth valve 36, the ninth valve 39, the twelfth valve 42, the fifteenth valve 45, the seventeenth valve 47 and the nineteenth valve 49 are opened, and the steam turbine 1 operates under a back pressure working condition; the primary net water is heated in the condenser 2 and then is conveyed to the water-water heat exchanger 62 of the secondary heat exchange station 6 to heat the secondary net water, and then the heated secondary net water is conveyed to a heat user to supply heat;
during the high and cold period of heating season, only the first valve 31, the fourth valve 34, the fifth valve 35, the seventh valve 37, the eighth valve 38, the tenth valve 40, the eleventh valve 41, the thirteenth valve 43, the fourteenth valve 44, the sixteenth valve 46, the seventeenth valve 47 and the twenty second valve 52 are opened, the hydrophobic heat exchanger 5, the condenser 2 and the heat-supply-network heat exchanger 4 are connected in series, the steam turbine 1 is operated under the back pressure working condition, the large-temperature-difference heat pump 61 is put into operation, the large-temperature-difference heat pump 61 and the water-supply-network heat exchanger 62 are connected in series, primary network backwater is subjected to primary heating in the hydrophobic heat exchanger 5 and then enters the condenser 2 for secondary heating, then enters the heat-supply-network heat exchanger 4 for tertiary heating, and finally is conveyed to the secondary heat exchange station 6 through the primary-supply-network water supply pipe 17; the primary network water supply is firstly used as a driving heat source of the large-temperature difference heat pump 61 for primary cooling, then enters the water-water heat exchanger 62 for secondary cooling, then is used as a low-temperature heat source for tertiary cooling, and finally returns to the thermal power plant through the primary network water return pipe 14; the secondary net backwater conveyed by the secondary net backwater pipe 22 is firstly subjected to primary heating by a water-water heat exchanger 62, then enters a large-temperature difference heat pump 61 for secondary heating, and is conveyed to a heat user for heat supply by a secondary net water supply pipe 27.
In the high and cold period of heating season, the drain flow and the primary network backwater flow entering the drain heat exchanger 5 can be regulated by opening and regulating the opening of the ninth valve 39 and the twenty-first valve 51 and regulating the opening of the eighth valve 38 and the twenty-second valve 52, so that the primary network backwater temperature entering the condenser 2 can be regulated;
if the temperature of the primary network backwater is higher than a specified value, closing a seventh valve 37, opening a ninth valve 39 and a twentieth valve 50, enabling the hydrophobic heat exchanger 5 and the condenser 2 to be connected in parallel, then connecting the hydrophobic heat exchanger 5 and the condenser 2 in series, and enabling the primary network backwater to enter the heat exchanger 4 for secondary heating after primary heating is carried out on the hydrophobic heat exchanger 5 and the condenser 2 respectively;
in the high and cold period of heating season, the opening of the seventeenth valve 47, the eighteenth valve 48, the sixteenth valve 46 and the nineteenth valve 49 can be opened and regulated to regulate the secondary network backwater flow entering the large-temperature difference heat pump 61 and the water-water heat exchanger 62, so as to regulate the temperature of the secondary network water supply;
if the water supply temperature of the secondary network required by the heat user is lower than the specified value, closing the sixteenth valve 46, opening the eighteenth valve 48 and the nineteenth valve 49, enabling the large-temperature-difference heat pump 61 and the water-water heat exchanger 62 to be connected in parallel, enabling two paths of water returning from the secondary network to enter the large-temperature-difference heat pump 61 and the water-water heat exchanger 62 at the same time for heating, and conveying heated secondary network water to the heat user for heat supply through the secondary network water supply pipe 27 after mixing; at this time, the water flow rate of the secondary network entering the large-temperature difference heat pump 61 and the water-water heat exchanger 62 is changed by adjusting the opening degrees of the seventeenth valve 47 and the eighteenth valve 48, so that the temperature of the secondary network water supply is adjusted.
In the specific operation method of the embodiment, when the flow rates of the primary network water supply and the secondary network water supply flowing through each device are adjusted, the opening degree of each valve is adjusted mainly by remotely transmitting the opening degree signal of the valve through the DCS system so as to realize the adjustment of the flow rate.
In the specific operation method of the embodiment, when the water return temperature of the primary network entering the condenser 2 and the water supply temperature of the secondary network for supplying heat to the heat user are adjusted, the specific measures are mainly realized by changing the opening of the valve, and include: firstly, the fluid flow rate flowing through each device is changed, and secondly, the connection mode of the system is changed.
Although the present invention is described with reference to the above embodiments, it should be understood that the invention is not limited to the embodiments described above, but is capable of modification and variation without departing from the spirit and scope of the present invention.
Claims (5)
1. A low vacuum heating system of coupling large temperature difference heat pump, its characterized in that: the device comprises a steam turbine (1), a condenser (2), a cooling tower (3), a heat supply network heat exchanger (4), a drainage heat exchanger (5) and a secondary heat exchange station (6); the secondary heat exchange station (6) comprises a large-temperature-difference heat pump (61) and a water-water heat exchanger (62); the steam turbine (1) is characterized in that a steam outlet of the steam turbine (1) is connected with a condenser (2), the condenser (2) is connected with a cooling tower (3) through a circulating water supply pipe (12) and a circulating water return pipe (13), a second valve (32) is arranged on the circulating water supply pipe (12), a third valve (33) is arranged on the circulating water return pipe (13), a steam inlet of the heat supply network heat exchanger (4) is connected with a heating steam outlet of the steam turbine (1) through a heating steam extraction pipe (11), a first valve (31) is arranged on the heating steam extraction pipe (11), a water drain outlet of the heat supply network heat exchanger (4) is connected with a water drain inlet of the water drain heat exchanger (5) through a first water drain pipe (20), and a water drain outlet of the water drain heat exchanger (5) is connected with a second water drain pipe (21); one end of a primary net return pipe (14) is connected with a primary net water outlet of a water-water heat exchanger (62), the other end of the primary net return pipe (14) is connected with a circulating water outlet of a third valve (33), and a large-temperature-difference heat pump (61) and a hydrophobic heat exchanger (5) are sequentially arranged on the primary net return pipe (14) along the water flowing direction; one end of a primary net water supply pipe (17) is connected with a primary net water inlet of a water-water heat exchanger (62), the other end of the primary net water supply pipe (17) is connected with a circulating water inlet of a second valve (32), and a heat supply net heat exchanger (4) and a large-temperature-difference heat pump (61) are sequentially arranged on the primary net water supply pipe (17) along the water flowing direction; the secondary network water return pipe (22) is connected with the water-water heat exchanger (62) through a secondary network water return A branch pipe (23), the secondary network water return pipe (22) is also connected with the large-temperature-difference heat pump (61) through a secondary network water return B branch pipe (24), a seventeenth valve (47) is arranged on the secondary network water return A branch pipe (23), an eighteenth valve (48) is arranged on the secondary network water return B branch pipe (24), a secondary network water outlet of the water-water heat exchanger (62) is connected with a heat network water outlet of the eighteenth valve (48) through a secondary network water supply A branch pipe (25), a secondary network water outlet of the water-water heat exchanger (62) is also connected with the secondary network water supply pipe (27) through a secondary network water supply B branch pipe (26), a sixteenth valve (46) is arranged on the secondary network water supply A branch pipe (25), a nineteenth valve (49) is arranged on the secondary network water supply B branch pipe (26), and the secondary network water outlet of the secondary network water supply pipe (27) is connected with the large-temperature-difference heat pump (61);
a first backwater bypass (15) is arranged on the backwater side of the primary network of the hydrophobic heat exchanger (5), an eighth valve (38) is arranged on the backwater inlet of the primary network of the hydrophobic heat exchanger (5), a seventh valve (37) is arranged on the backwater outlet of the primary network of the hydrophobic heat exchanger (5), and a ninth valve (39) is arranged on the first backwater bypass (15) of the hydrophobic heat exchanger (5); a first drain bypass (29) is arranged on the drain side of the drain heat exchanger (5), a twenty-second valve (52) is arranged on a drain inlet of the drain heat exchanger (5), and a twenty-first valve (51) is arranged on the first drain bypass (29);
a primary net backwater inlet of the seventh valve (37) is connected with a circulating water inlet of the second valve (32) through a third water supply bypass (28), and a twentieth valve (50) is arranged on the third water supply bypass (28);
a second backwater bypass (16) is arranged on the backwater side of the primary network of the large-temperature-difference heat pump (61), a fourteenth valve (44) is arranged on the backwater inlet of the primary network of the large-temperature-difference heat pump (61), a thirteenth valve (43) is arranged on the backwater outlet of the primary network of the large-temperature-difference heat pump (61), and a fifteenth valve (45) is arranged on the second backwater bypass (16);
a first water supply bypass (18) is arranged on the primary network water supply side of the heat supply network heat exchanger (4), a fourth valve (34) is arranged on the primary network water supply inlet of the heat supply network heat exchanger (4), a fifth valve (35) is arranged on the primary network water supply outlet of the heat supply network heat exchanger (4), and a sixth valve (36) is arranged on the first water supply bypass (18);
a second water supply bypass (19) is arranged on the primary network water supply side of the large-temperature-difference heat pump (61), a tenth valve (40) is arranged on the primary network water supply inlet of the large-temperature-difference heat pump (61), an eleventh valve (41) is arranged on the primary network water supply outlet of the large-temperature-difference heat pump (61), and a twelfth valve (42) is arranged on the second water supply bypass (19).
2. The low vacuum heating system coupled to a large temperature differential heat pump of claim 1, wherein: the large-temperature-difference heat pump (61) uses primary net water supply as a driving heat source, uses primary net backwater as a low-temperature heat source, and recovers the waste heat of the primary net backwater to heat secondary net water, thereby realizing large-temperature-difference heat supply.
3. The low vacuum heating system coupled to a large temperature differential heat pump of claim 1, wherein: after the heat supply network drainage of the heat supply network heat exchanger (4) is subjected to secondary heat exchange through the drainage heat exchanger (5), the temperature is further reduced, and the heat supply network drainage after the secondary heat exchange and temperature reduction is conveyed to a low-pressure heat recovery system of the steam turbine (1) through a second drainage pipe (21).
4. A method of operating a low vacuum heating system coupled to a large temperature difference heat pump as claimed in any one of claims 1 to 3, wherein: the operation method is as follows:
when the heating system is not in heating season, only the second valve (32) and the third valve (33) are opened, the steam turbine (1) operates under a pure condensation working condition, circulating water is heated in the condenser (2) and then is conveyed to the cooling tower (3) for cooling, and the cooled circulating water returns to the condenser (2) for heating;
during the initial stage and the final stage of the heating season, only opening a sixth valve (36), a ninth valve (39), a twelfth valve (42), a fifteenth valve (45), a seventeenth valve (47) and a nineteenth valve (49), and operating the steam turbine (1) under a back pressure working condition; the primary net water is heated in the condenser (2) and then is conveyed to a water-water heat exchanger (62) of the secondary heat exchange station (6), the secondary net water is heated, and then the heated secondary net water is conveyed to a heat user for heat supply;
during a high-cold period in a heating season, only a first valve (31), a fourth valve (34), a fifth valve (35), a seventh valve (37), an eighth valve (38), a tenth valve (40), an eleventh valve (41), a thirteenth valve (43), a fourteenth valve (44), a sixteenth valve (46), a seventeenth valve (47) and a twenty second valve (52) are opened, a hydrophobic heat exchanger (5), a condenser (2) and a heat supply network heat exchanger (4) are connected in series, a steam turbine (1) operates under a back pressure working condition, a large-temperature-difference heat pump (61) is operated, the large-temperature-difference heat pump (61) and a water-water heat exchanger (62) are connected in series, primary network backwater is heated in the hydrophobic heat exchanger (5), then enters the condenser (2) for secondary heating, then enters the heat supply network heat exchanger (4) for tertiary heating, and finally is conveyed to a secondary heat exchange station (6) through a primary network water supply pipe (17); the primary network water supply is firstly used as a driving heat source of a large-temperature difference heat pump (61) to perform primary cooling, then enters a water-water heat exchanger (62) to perform secondary cooling, then is used as a low-temperature heat source to enter the large-temperature difference heat pump (61) to perform tertiary cooling, and finally returns to the thermal power plant through a primary network water return pipe (14); the secondary net backwater conveyed by the secondary net backwater pipe (22) is firstly subjected to primary heating in the water-water heat exchanger (62), then enters the large-temperature difference heat pump (61) to be subjected to secondary heating, and is conveyed to a heat user through the secondary net water supply pipe (27) to supply heat.
5. The method of operating a low vacuum heating system coupled to a large temperature differential heat pump of claim 4, wherein:
during the high and cold period of a heating season, the opening of the ninth valve (39) and the twenty-first valve (51) are opened and regulated, the opening of the eighth valve (38) and the twenty-second valve (52) are regulated, and the drainage flow and the primary network backwater flow entering the drainage heat exchanger (5) are regulated, so that the primary network backwater temperature entering the condenser (2) is regulated;
when the temperature of primary network backwater is higher than a specified value in a high-cold period of a heating season, closing a seventh valve (37) at the moment, opening a ninth valve (39) and a twentieth valve (50), enabling the hydrophobic heat exchanger (5) and the condenser (2) to be connected in parallel, then connecting the hydrophobic heat exchanger with the heat network heat exchanger (4) in series, and enabling the primary network backwater to enter the heat network heat exchanger (4) for secondary heating after the hydrophobic heat exchanger (5) and the condenser (2) are respectively subjected to primary heating;
during the high and cold period of a heating season, the opening of a seventeenth valve (47), an eighteenth valve (48), a sixteenth valve (46) and a nineteenth valve (49) is opened and regulated, and the secondary network backwater flow entering a large-temperature difference heat pump (61) and a water-water heat exchanger (62) is regulated, so that the temperature of secondary network water supply is regulated;
when the water supply temperature of the secondary network required by a heat user is lower than a specified value in the high and cold period of a heating season, closing a sixteenth valve (46), opening an eighteenth valve (48) and a nineteenth valve (49), enabling a large-temperature-difference heat pump (61) and a water-water heat exchanger (62) to be connected in parallel, enabling two paths of water returning of the secondary network to enter the large-temperature-difference heat pump (61) and the water-water heat exchanger (62) simultaneously for heating, and conveying heated secondary network water to the heat user for heat supply through a secondary network water supply pipe (27) after mixing; at the moment, the opening degree of the seventeenth valve (47) and the eighteenth valve (48) is adjusted to change the water flow rate of the secondary network entering the large-temperature difference heat pump (61) and the water-water heat exchanger (62), so that the temperature of the secondary network water supply is adjusted.
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| CN110230521B (en) * | 2019-03-12 | 2023-09-19 | 华电电力科学研究院有限公司 | Cascade heating system for heat pump by cutting off steam inlet coupling of low-pressure cylinder of thermoelectric unit and adjusting method |
| CN110274291B (en) * | 2019-05-28 | 2023-08-29 | 华电电力科学研究院有限公司 | Online water quality treatment system for primary heat supply network water and operation method thereof |
| CN110715347A (en) * | 2019-10-30 | 2020-01-21 | 瑞纳智能设备股份有限公司 | One-network balancing device and control method |
| CN110947298A (en) * | 2019-12-27 | 2020-04-03 | 浙江德创环保科技股份有限公司 | Desulfurizing tower slurry condensation white-removing system |
| CN114263957A (en) * | 2021-12-06 | 2022-04-01 | 河北工业大学 | Self-capacity-increasing heating system with energy coupling of primary/secondary heating power pipe network |
| CN114909696B (en) * | 2022-04-28 | 2024-06-25 | 哈尔滨工业大学 | Adsorption type low-pressure CO2Gas-heat combined storage and combined supply device and operation method thereof |
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