A system and method for cogeneration of waste heat from steam turbines in a solar thermal power station

Abstract

The present invention provides a system and method for heat and power cogeneration of a steam turbine waste heat in a solar thermal power station. The system mainly includes a steam turbine, a steam-water heat exchanger, and a compression heat pump. The steam turbine is connected to the steam side of the steam-water heat exchanger through a steam exhaust extraction pipeline, and the water side of the steam-water heat exchanger is connected to the compression heat pump through a circulating water pipeline. The compression heat pump is connected to a heating water pipeline. The latent heat of the steam exhaust from the steam turbine is transferred to the circulating water through the steam-water heat exchanger, and the circulating water with low-grade heat is converted into heating water with high-grade heat through the compression heat pump to provide heat to users, wherein the circulating water with the heat of the exhaust steam is stored in a circulating water storage tank, and the heating water with high-grade heat is stored in a heating water storage tank, and continuous heating is still achieved after the steam turbine is shut down. The present invention effectively improves the heat grade and comprehensive energy utilization rate, realizes peak cooling, solves the attenuation problem of the power station condensation system, and the problem of intermittent waste heat from the solar thermal power station, and is conducive to reducing heating costs and carbon emissions.

Description

Technical Field

[0001] The present invention relates to a system and method for cogeneration of waste heat from a steam turbine of a solar thermal power station, which is used for recovering waste heat from exhaust steam of a steam turbine of a power station, and belongs to the field of waste heat utilization, and in particular to the field of waste heat utilization from a steam turbine of a solar thermal power station. Background Art

[0002] The steam turbine of the power station uses steam to generate electricity. After the steam has been used, it must be discharged and cooled by circulating cooling water to become condensed water. The circulating water absorbs the heat of the exhaust steam and then enters the cooling tower to dissipate the heat. We often see white smoke coming out of the cooling tower, which is the loss of the cooling source of the steam turbine.

[0003] The existing steam turbine waste heat utilization system based on transcritical carbon dioxide heat pump is provided with a transcritical CO2 heat pump. After the waste heat of steam turbine exhaust is cooled by circulating water, the waste heat enters the transcritical CO2 heat pump. In the CO2 heat pump, the heat pump compressor is driven by a driving device, so that the waste heat in the circulating water is recovered and enters the circulating water of the heat network, realizing the recovery and utilization of steam turbine exhaust waste heat. The disadvantages of the existing technology are:

[0004] (1) The system limits the heat pump to a transcritical carbon dioxide heat pump, which is a single type of heat pump. In addition, the transcritical carbon dioxide heat pump technology is relatively new, and the national and industry standards are not perfect. In addition, the critical pressure of carbon dioxide is high, and it is a high-pressure equipment, so there are certain problems in maintenance;

[0005] (2) The system can only provide heat when the steam turbine is running, and cannot provide continuous heat after the steam turbine is shut down. According to the working characteristics of the power plant, the operating period is divided into valley power period and peak power period. The load of the power plant is variable, and the discharge of high-temperature steam and slag is intermittent, which means that the heat of waste heat will change with the change of the working period of the power plant.

[0006] Therefore, providing a system that can effectively utilize the low-grade heat of power plant exhaust steam and continue to provide high-temperature heating water after the turbine is shut down has become an urgent problem to be solved. Summary of the invention

[0007] To solve the above problems, the present invention is implemented through the following technical solutions: The present invention provides a solar thermal power station steam turbine waste heat cogeneration system, the system mainly includes a steam turbine, a steam-water heat exchanger, and a compression heat pump. The steam turbine is connected to the steam side of the steam-water heat exchanger through a waste steam extraction pipeline, the water side of the steam-water heat exchanger is connected to the compression heat pump through a circulating water pipeline, the compression heat pump is connected to the heating water pipeline, the steam turbine exhaust steam latent heat is transferred to the circulating water through the steam-water heat exchanger, and the circulating water with low heat quality is converted into heating water with high heat quality through the compression heat pump to provide heat to users, wherein the circulating water with exhaust steam heat is stored in a circulating water storage tank, and the heating water with high heat quality is stored in a heating water storage tank, so that continuous heating is achieved after the steam turbine is shut down.

[0008] On one hand, the present invention provides a solar thermal power plant steam turbine waste heat cogeneration system, comprising a steam turbine I, an air cooling tower II, a main heat exchanger III, a circulating water storage tank IV, a compression heat pump V, a circulating pump VI, an electric heater VII, a heating water storage tank VIII, an in-plant heating heat exchanger IX, a heating pump X and a first domestic hot water heat exchanger XI;

[0009] Wherein, the steam turbine I is connected to the main heat exchanger III through an exhaust steam extraction pipeline;

[0010] The main heat exchanger III is connected to the circulating pump VI, the circulating water storage tank IV and the compression heat pump V through a circulating water pipeline;

[0011] The electric heater VII is connected to the heating water storage tank VIII, the in-plant heating heat exchanger IX, the heating pump X and the first domestic hot water heat exchanger XI;

[0012] The heating pump X is connected to the heating water storage tank VIII, the in-plant heating heat exchanger IX, and the heating pump X and the first domestic hot water heat exchanger XI;

[0013] The main heat exchanger III is used to recover the waste heat of the low-grade heat exhaust steam in the steam turbine I, and the circulating water obtained by the heat is stored in the circulating water storage tank IV. The compression heat pump V is used to convert the circulating water with low-grade heat into heating water with high-grade heat. A part of the heating water with high-grade heat is stored in the heating water storage tank VIII, and the other part is directly used for heating the factory area and providing domestic hot water for users.

[0014] Furthermore, in the plant heating heat exchanger IX, high-quality heating water flows in from the first water supply port e, and flows out from the low-temperature water first outlet f after heat exchange; in the first domestic hot water heat exchanger XI, high-quality heating water flows in from the second water supply port m, and flows out from the low-temperature water second outlet n after heat exchange, and the high-temperature domestic hot water that has obtained heat flows out from the outlet g.

[0015] Furthermore, it also includes a second domestic hot water heat exchanger XII, and the exhaust steam of the steam turbine I is also connected to the second domestic hot water heat exchanger XII through the exhaust steam extraction pipeline. In the second domestic hot water heat exchanger XII, the exhaust steam of the steam turbine I flows in from the water supply port through the eighteenth valve 18, and the condensed water after losing heat flows out from the low-temperature water outlet through the nineteenth valve 19, and the domestic hot water with high heat quality flows out from the outlet i.

[0016] Furthermore, the compression heat pump V is an electrically driven heat pump for converting low-grade heat in circulating water into heating water with high-grade heat.

[0017] Furthermore, the water in the circulating water storage tank IV and the heating water storage tank VIII can be replaced with light water or heavy water.

[0018] Furthermore, the main heat exchanger III is connected to the first valve 1 and the second valve 2; the circulating water storage tank IV is connected to the fourth valve 4, the fifth valve 5, the sixth valve 6 and the seventh valve 7; the heating water storage tank VIII is connected to the eighth valve 8, the ninth valve 9, the tenth valve 10 and the eleventh valve 11.

[0019] Another aspect of the present invention provides a method for cogeneration of heat and power from waste heat of a steam turbine in a solar thermal power station, the method comprising the following steps:

[0020] S1. When the steam turbine I is running, the heat from the exhaust steam of the steam turbine is stored in the circulating water storage tank IV: the exhaust steam of the steam turbine I enters the main heat exchanger III through the exhaust steam extraction pipeline to exchange heat with the circulating water, and the circulating water with heat is flowed into the circulating water storage tank IV for storage;

[0021] S2. During off-peak or power-wasting periods, the compression heat pump V is started to transfer the heat of the circulating water in the circulating water storage tank IV to the heating water through the compression heat pump V, and then the low-grade heat in the circulating water is transferred to the heating water with high-grade heat. A part of the heating water with high-grade heat directly enters the heating network to heat the factory area and provide domestic hot water for users, and the other part is stored in the heating water storage tank VIII;

[0022] S3. During off-peak or non-wasted power periods, the compression heat pump V is shut down, and the heating water with high-quality heat stored in the heating water storage tank VIII during off-peak or non-wasted power periods is directly used for heating the factory and providing domestic hot water.

[0023] Furthermore, when the solar thermal power station is not generating electricity, an electric heater VII is provided as a supplementary heating supply. To save electricity costs, the electric heater VII is started during off-peak hours. A portion of the high-quality thermal heating water generated by the electric heater VII is stored in the heating water storage tank VIII, so that continuous heating can be achieved even after the electric heater VII is shut down; the other portion flows into the plant heating heat exchanger IX for heating the plant, and flows into the first domestic hot water heat exchanger XI to provide domestic hot water for users.

[0024] Furthermore, in the plant heating heat exchanger IX, high-quality heating water flows in from the first water supply port e, and flows out from the low-temperature water first outlet f after heat exchange; in the first domestic hot water heat exchanger XI, high-quality heating water flows in from the second water supply port m, and flows out from the low-temperature water second outlet n after heat exchange, and high-temperature domestic hot water flows out from the outlet g.

[0025] Furthermore, in summer when the exhaust steam temperature is high, when the steam turbine I is running, the heat from the exhaust steam of the steam turbine I is directly passed into the second domestic hot water heat exchanger XII, and domestic hot water with high heat quality is directly obtained in the second domestic hot water heat exchanger XII.

[0026] Furthermore, in step S3, the eighth valve 8, the tenth valve 10, the thirteenth valve 13, the fourteenth valve 14 and the fifteenth valve 15 are closed, and the ninth valve 9, the eleventh valve 11 and the twelfth valve 12 are opened, and the heating water with high-grade heat stored in the heating water storage tank VIII flows into the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI through the eleventh valve 11 respectively, and the low-temperature water after heat exchange in the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI flows from the twelfth valve 12 through the ninth valve 9 and returns to the heating water storage tank VIII under the drive of the heating pump X, thereby forming a cycle.

[0027] The above technical solution of the present invention has the following beneficial technical effects:

[0028] The present invention utilizes a compression heat pump to convert low-grade exhaust steam heat into high-grade heat for heating water, thereby becoming a heating method that can replace coal, gas, electricity and the like, and is beneficial to reducing heating costs and carbon emissions; the present invention can effectively utilize the low-grade waste heat of turbine exhaust steam, effectively improving the heat grade and comprehensive energy utilization rate; the compression heat pump in the present invention can be used as a refrigerator in summer for peak cooling, reducing back pressure, solving the attenuation problem of the power station condensation system in summer, and improving the power generation efficiency of the unit; the present invention solves the problem of intermittent waste heat in solar thermal power stations by setting a heating water storage tank to store high-grade hot water. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a composition diagram of an exemplary solar thermal power station steam turbine waste heat cogeneration system of the present invention.

[0030] Figure markings: I-steam turbine; II-air cooling tower; III-main heat exchanger; IV-circulating water storage tank; V-compression heat pump; VI-circulating pump; VII-electric heater; VIII-heating water storage tank; IX-plant heating heat exchanger; X-heating pump; XI-first heat exchanger for domestic hot water; XII-second heat exchanger for domestic hot water; 1-first valve; 2-second valve; 3-third valve; 4-fourth valve; 5-fifth valve; 6-sixth valve; 7-seventh valve; 8-eighth valve; 9-ninth valve; 10-tenth valve; 11-eleventh valve; 12-twelfth valve; 13-thirteenth valve; 14-fourteenth valve; 15-fifteenth valve; 16-sixteenth valve; 17-seventeenth valve; 18-eighteenth valve; 19-nineteenth valve. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

[0032] An exemplary composition of a CSP power plant steam turbine waste heat cogeneration system of the present invention is as follows: Figure 1 As shown, it includes a steam turbine I, an air-cooling tower II, a main heat exchanger III, a circulating water storage tank IV, a compression heat pump V, a circulating pump VI, an electric heater VII, a heating water storage tank VIII, an in-plant heating heat exchanger IX, a heating pump X, a first domestic hot water heat exchanger XI, a second domestic hot water heat exchanger XII, a first valve 1, a second valve 2, a third valve 3, a fourth valve 4, a fifth valve 5, a sixth valve 6, a seventh valve 7, an eighth valve 8, a ninth valve 9, a tenth valve 10, an eleventh valve 11, a twelfth valve 12, a thirteenth valve 13, a fourteenth valve 14, a fifteenth valve 15, a sixteenth valve 16, a seventeenth valve 17, an eighteenth valve 18, and a nineteenth valve 19. The steam turbine I is connected to the main heat exchanger III and the second domestic hot water heat exchanger XII through the exhaust steam extraction pipeline. The main heat exchanger III is connected to the compression heat pump V through the circulating water pipeline. The compression heat pump V is connected to the heating water storage tank VIII, the plant heating heat exchanger IX, the heating pump X and the first domestic hot water heat exchanger X. The system is used to recover the waste heat of the steam turbine exhaust steam, absorb the heat of the circulating water with low heat quality to obtain the heating water with high heat quality for heating the plant area and providing domestic hot water for users.

[0033] Example 1

[0034] When the steam turbine I is running, it stores heat in the circulating water storage tank IV. The operating status of this process is as follows: Figure 1As shown, the first valve 1 and the second valve 2 are open. First, the exhaust steam of the steam turbine I enters the main heat exchanger III through the exhaust steam extraction pipeline from the steam inlet pipeline a, and the condensed water after heat exchange is discharged through the return pipeline b. The fourth valve 4 and the sixth valve 6 are opened, and the circulating water after heat exchange flows out through the high-temperature outlet pipeline d and flows into the circulating water storage tank IV for storage; the circulating water at the bottom of the circulating water storage tank IV with a lower temperature is driven by the circulating pump VI to continue to absorb heat from the low-temperature water supply pipeline c to the main heat exchanger III, and then flows back to the circulating water storage tank IV for storage, thereby forming a cycle.

[0035] Example 2

[0036] On the basis of Example 1, when the steam turbine 1 is shut down, the operating state of the process is as follows: Figure 1 As shown, the first valve 1, the second valve 2, the fourth valve 4 and the sixth valve 6 are closed, and the circulating water with low-grade heat stored in the circulating water storage tank IV is converted into heating water with high-grade heat through the compression heat pump V, wherein a part of the heating water directly enters the heating network to heat the factory area and provide domestic hot water for users, and the other part is stored in the heating water storage tank. The third valve 3, the fifth valve 5 and the seventh valve 7 are opened, and the circulating water flows out of the seventh valve 7 and enters the compression heat pump V for heat exchange, and the circulating water that absorbs heat flows back to the circulating water storage tank IV through the third valve 3 through the circulating pump VI; the eighth valve 8 and the tenth valve 10, the thirteenth valve 13, the fourteenth valve 14 and the fifteenth valve 15 are opened, and the high-grade hot water that absorbs heat through the compression heat pump IV flows through the thirteenth valve 13, and a part of it passes through the eighth valve 8 and is stored in the heating water storage tank VIII, and the heating water at the bottom of the heating water storage tank VIII with a lower temperature is returned to the circulating water storage tank IV. Driven by the heating pump X, the stored water enters the compression heat pump V from the fourteenth valve 14 to continue absorbing heat, and then flows back to the heating water storage tank VIII for storage, thus forming a cycle; the other part flows into the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI through the fifteenth valve 15 for heating the plant and providing domestic hot water. Driven by the heating pump X, the low-temperature water after heat exchange enters the compression heat pump V from the fourteenth valve 14 to continue absorbing heat from the circulating water storage pump, and then flows out of the high-quality heating water from the thirteenth valve 13, thus forming a cycle. Among them, in the plant heating heat exchanger IX, the high-quality heating water flows in from the first water supply port e and flows out from the first low-temperature water outlet f; in the first domestic hot water heat exchanger XI, the high-quality heating water flows in from the second water supply port m and flows out from the second low-temperature water outlet n, and the high-temperature domestic hot water that obtains heat after heat exchange flows out from the outlet g.

[0037] Example 3

[0038] On the basis of Example 1, when the compression heat pump V is shut down, the heating water with high-quality heat stored in the heating water storage tank VIII during the off-peak or abandoned power period is directly used for heating in the factory and providing domestic hot water for users. The operating status of this process is as follows: Figure 1 As shown. The eighth valve 8, the tenth valve 10, the thirteenth valve 13, the fourteenth valve 14 and the fifteenth valve 15 are closed, and the ninth valve 9, the eleventh valve 11 and the twelfth valve 12 are opened. The heating water with high-grade heat stored in the heating water storage tank VIII flows through the eleventh valve 11 into the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI for heating in the plant and providing domestic hot water for users. The low-temperature water after heat exchange flows from the twelfth valve 12 through the ninth valve 9 and returns to the heating water storage tank VIII under the drive of the heating pump X, thus forming a cycle. Among them, in the plant heating heat exchanger IX, high-grade heating water flows in from the first water supply port e and flows out from the first low-temperature water outlet f; in the first domestic hot water heat exchanger XI, high-grade heating water flows in from the second water supply port m and flows out from the second low-temperature water outlet n. The high-temperature domestic hot water obtained after heat exchange flows out from the outlet g.

[0039] Example 4

[0040] On the basis of Examples 1-3, in special cases where the steam turbine is shut down and does not generate electricity (such as during the winter maintenance period or continuous rainy days, etc.), an electric heater is used to provide high-quality heat for heating water. The operating state of this process is as follows Figure 1As shown, first, in order to save electricity costs, the electric heater VII is started during the off-peak period, the ninth valve 9, the eleventh valve 11 and the twelfth valve 12 are closed; the eighth valve 8, the tenth valve 10, the fifteenth valve 15, the sixteenth valve 16 and the seventeenth valve 17 are opened. A part of the heating water with high-grade heat generated by the electric heater VII is stored in the heating water tank VIII through the eighth valve 8. The heating water with lower temperature at the bottom of the heating water tank VIII enters the electric heater VII from the seventeenth valve 17 under the drive of the heating pump X to absorb heat, and then flows back to the heating water tank VIII for storage, thus forming a cycle; another part of the heating water with high-grade heat passes through the fifteenth valve 15 and flows into the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI respectively to provide heating in the plant and domestic hot water for users. The low-temperature water after heat exchange is driven by the heating pump X, enters the electric heater VII from the seventeenth valve 17 to continue to be heated into heating water with high-grade heat, and then flows out from the sixteenth valve 16, thus forming a cycle. Among them, in the factory heating heat exchanger IX, high-grade heating water flows in from the first water supply port e and flows out from the low-temperature water first outlet f; in the first domestic hot water heat exchanger XI, high-grade heating water flows in from the second water supply port m and flows out from the low-temperature water second outlet n, and the high-temperature domestic hot water obtained after heat exchange flows out from the outlet g.

[0041] Example 5

[0042] Based on Example 1-3, in summer, the exhaust steam temperature is high and the heating demand is only for domestic hot water. Domestic hot water is obtained by directly exchanging heat with the exhaust steam through the second domestic hot water heat exchanger XII. The operating state of this process is as follows Figure 1 As shown, the first valve 1 and the second valve 2 are closed; the eighteenth valve 18 and the nineteenth valve 19 are opened. First, the exhaust steam of the steam turbine I enters the second domestic hot water heat exchanger XII through the exhaust steam extraction pipeline from the steam inlet pipeline a, and the condensed water after heat exchange is discharged through the return pipeline b. In the second domestic hot water heat exchanger XII, the exhaust steam of the steam turbine I flows in from the water supply port through the eighteenth valve 18, the condensed water after heat exchange flows out from the low-temperature water outlet through the nineteenth valve 19, and the domestic hot water that obtains heat after heat exchange flows out from the outlet i.

[0043] Example 6

[0044] On the basis of Examples 1-5, the present invention further utilizes a CSP steam turbine waste heat cogeneration system in Examples 1-5 to implement a CSP steam turbine waste heat cogeneration method, which comprises the following steps:

[0045] Step S1, when the steam turbine I is running, the heat from the exhaust steam of the steam turbine is stored in the circulating water storage tank IV: the exhaust steam of the steam turbine I enters the main heat exchanger III through the exhaust steam extraction pipeline to exchange heat with the circulating water, and the heated circulating water flows into the circulating water storage tank IV for storage;

[0046] Step S2: During off-peak or power-wasting periods, the heat of the circulating water in the circulating water storage tank IV is transferred to the heating water through the compression heat pump V, and the circulating water with low-grade heat is converted into heating water with high-grade heat through the compression heat pump V. A part of the heating water with high-grade heat directly enters the heating network to heat the plant area and provide domestic hot water for users, and the other part is stored in the heating water storage tank VIII. When the solar thermal power station is not generating electricity, the electric heater VII is started during the off-peak period, and a part of the high-grade heat heating water generated by the electric heater VII is stored in the heating water storage tank VIII, and the other part flows into the plant area heating heat exchanger IX to heat the plant, and flows into the first domestic hot water heat exchanger XI to provide domestic hot water for users. When the exhaust steam temperature is high in summer, the steam turbine I is running, and the heat from the exhaust steam of the steam turbine directly enters the second domestic hot water heat exchanger XII, and heat is exchanged in the second domestic hot water heat exchanger XII to obtain heating water, and the heating water provides domestic hot water for users;

[0047] Step S3, during the off-peak or non-wasted power period, the compression heat pump V is shut down, and the heating water with high-quality heat stored in the heating water storage tank VIII during the off-peak or non-wasted power period is directly used for heating in the factory and providing domestic hot water for users. The eighth valve 8, the tenth valve 10, the thirteenth valve 13, the fourteenth valve 14 and the fifteenth valve 15 are closed, and the ninth valve 9, the eleventh valve 11 and the twelfth valve 12 are opened. The heating water with high-quality heat stored in the heating water storage tank VIII flows into the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI through the eleventh valve 11, respectively. The low-temperature water after heat exchange in the plant heating heat exchanger IX and the first domestic hot water heat exchanger XI, driven by the heating pump X, flows from the twelfth valve 12 through the ninth valve 9 back to the heating water storage tank VIII, thereby forming a cycle. In the plant heating heat exchanger IX, high-quality heating water flows in from the first water supply port e and flows out from the low-temperature water first outlet f; in the first domestic hot water heat exchanger XI, high-quality heating water flows in from the second water supply port m and flows out from the low-temperature water second outlet n, and the high-temperature domestic hot water obtained after heat exchange flows out from the outlet g.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and variations. The above-mentioned embodiments are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described embodiments should be considered illustrative rather than restrictive in any respect. The scope of the present invention shall be described by the appended claims, and any changes equivalent to the intent and scope of the claims shall also be included within the scope of the present invention.

Claims

1. A method for combined heat and power generation of a steam turbine waste heat in a solar thermal power station, the combined heat and power generation method being implemented based on a combined heat and power generation system of a steam turbine waste heat in a solar thermal power station, the combined heat and power generation system comprising a steam turbine (I), an air cooling tower (II), a main heat exchanger (III), a circulating water storage tank (IV), a compression heat pump (V), a circulating pump (VI), an electric heater (VII), a heating water storage tank (VIII), an in-plant heating heat exchanger (IX), a heating pump (X) and a first domestic hot water heat exchanger (XI); in, The steam turbine (I) is connected to the main heat exchanger (III) via an exhaust steam extraction pipeline; The main heat exchanger (III) is connected to the circulation pump (VI), the circulation water storage tank (IV) and the compression heat pump (V) through a circulation water pipeline; The electric heater (VII) is connected to the heating water storage tank (VIII), the in-plant heating heat exchanger (IX), the heating pump (X) and the first domestic hot water heat exchanger (XI); The heating pump (X) is connected to the heating water storage tank (VIII), the in-plant heating heat exchanger (IX), the heating pump (X) and the first domestic hot water heat exchanger (XI); The main heat exchanger (III) is used to recover the waste heat of the low-grade heat exhaust steam in the steam turbine (I), and the circulating water obtained by the heat is stored in the circulating water storage tank (IV). The compression heat pump (V) is used to convert the circulating water with low-grade heat into heating water with high-grade heat. A part of the heating water with high-grade heat is stored in the heating water storage tank (VIII), and the other part is directly used for heating the factory area and providing domestic hot water for users. In the plant heating heat exchanger (IX), high-quality heating water flows in from the first water supply port (e), and flows out from the low-temperature water first water outlet (f) after heat exchange; in the domestic hot water first heat exchanger (XI), high-quality heating water flows in from the second water supply port (m), and flows out from the low-temperature water second water outlet (n) after heat exchange, and the high-temperature domestic hot water that has obtained heat flows out from the water outlet (g); It also includes a second domestic hot water heat exchanger (XII), and the exhaust steam of the steam turbine (I) is also connected to the second domestic hot water heat exchanger (XII) through an exhaust steam extraction pipeline; in the second domestic hot water heat exchanger (XII), the exhaust steam of the steam turbine (I) flows into the water supply port through the eighteenth valve (18), the condensed water after losing heat flows out from the low-temperature water outlet through the nineteenth valve (19), and the heating water with high heat quality flows out from the outlet (i); The compression heat pump (V) is an electrically driven heat pump for converting low-grade heat in the circulating water into heating water with high-grade heat; The water in the circulating water storage tank (IV) and the heating water storage tank (VIII) can be replaced with light water or heavy water; The main heat exchanger (III) is connected to the first valve (1) and the second valve (2); the circulating water storage tank (IV) is connected to the fourth valve (4), the fifth valve (5), the sixth valve (6) and the seventh valve (7); the heating water storage tank (VIII) is connected to the eighth valve (8), the ninth valve (9), the tenth valve (10) and the eleventh valve (11); The combined heat and power method comprises the following steps: S1. When the steam turbine (I) is running, the heat from the exhaust steam of the steam turbine is stored in the circulating water storage tank (IV): the exhaust steam of the steam turbine (I) enters the main heat exchanger (III) through the exhaust steam extraction pipeline to exchange heat with the circulating water, and the circulating water that has obtained the heat flows into the circulating water storage tank (IV) for storage; S2. During off-peak or power-wasting periods, the compression heat pump (V) is started to transfer the heat of the circulating water in the circulating water storage tank (IV) to the heating water through the compression heat pump (V), thereby transferring the low-grade heat in the circulating water to the heating water with high-grade heat. A portion of the heating water with high-grade heat directly enters the heating network to heat the factory area and provide domestic hot water for users, and the other portion is stored in the heating water storage tank (VIII); S3. During off-peak or non-wasted power periods, the compression heat pump (V) is shut down, and the heating water with high-quality heat stored in the heating water storage tank (VIII) during off-peak or non-wasted power periods is directly used for heating the factory and providing domestic hot water.

2. The method according to claim 1, characterized in that When the solar thermal power station is not generating electricity, an electric heater (VII) is provided as a supplementary heating. To save electricity costs, the electric heater (VII) is started during off-peak hours. A portion of the high-quality heat water generated by the electric heater (VII) is stored in the heating water storage tank (VIII), so that continuous heating can be achieved even after the electric heater (VII) is shut down. The other portion flows into the plant heating heat exchanger (IX) for heating the plant, and flows into the first domestic hot water heat exchanger (XI) for providing domestic hot water to users.

3. A method for combined heat and power generation of steam turbine waste heat from a solar thermal power station according to claim 1 or 2, characterized in that In the plant heating heat exchanger (IX), high-quality heating water flows in from the first water supply port (e), and after heat exchange, flows out from the low-temperature water first outlet (f); in the domestic hot water first heat exchanger (XI), high-quality heating water flows in from the second water supply port (m), and after heat exchange, flows out from the low-temperature water second outlet (n), and high-temperature domestic hot water flows out from the outlet (g).

4. A method for combined heat and power generation of steam turbine waste heat from a solar thermal power station according to claim 3, characterized in that: When the exhaust steam temperature is high in summer, when the steam turbine (I) is running, the heat from the exhaust steam of the steam turbine (I) is directly passed into the second domestic hot water heat exchanger (XII), and high-quality heating water is directly obtained in the second domestic hot water heat exchanger (XII), and the heating water provides domestic hot water for users.

5. A method for combined heat and power generation of steam turbine waste heat from a solar thermal power station according to claim 4, characterized in that: In step S3, the eighth valve (8), the tenth valve (10), the thirteenth valve (13), the fourteenth valve (14) and the fifteenth valve (15) are closed, and the ninth valve (9), the eleventh valve (11) and the twelfth valve (12) are opened, and the heating water with high-grade heat stored in the heating water storage tank (VIII) flows into the plant heating heat exchanger (IX) through the eleventh valve (11), and The low-temperature water after heat exchange in the first heat exchanger (XI) for domestic hot water (IX) and the first heat exchanger for domestic hot water (XI) flows from the twelfth valve (12) through the ninth valve (9) and returns to the heating water storage tank (VIII) under the drive of the heating pump (X), thereby forming a cycle.

Images