A heat supply and heat storage system and method based on a pumping machine

Abstract

The present invention relates to the technical field of coal-fired power generation, and specifically to a heat supply and heat storage system based on a back-up pump. The system includes a back-up pump and a high-pressure cylinder, both of which are connected to the main steam line of the boiler. The back-up pump, a high-pressure heating reheater, and a second-level heat storage heat exchanger are connected in sequence. The second-level heat storage heat exchanger is respectively connected to the high-pressure heating header and a deaerator. The back-up pump, a medium-pressure heating reheater, and a steam cooler are connected in sequence. The steam cooler is respectively connected to the medium-pressure heating header and the second-level heat storage heat exchanger. The high-pressure cylinder, a reheat heater, a medium-pressure cylinder, and a low-pressure cylinder are connected in sequence. The medium-pressure cylinder is connected to the first-level heat storage heat exchanger. The first-level heat storage heat exchanger is connected to the deaerator. The first-level heat storage heat exchanger, the second-level heat storage heat exchanger, a hot molten salt tank, a steam generator, and a cold molten salt tank are connected end to end. The steam generator is connected to the medium-pressure heating header and the low-pressure cylinder. Using this system, energy level matching of heat supply and thermoelectric decoupling of heat storage and power generation are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired power generation, and in particular to a heat supply and heat storage system and method based on a heat pump. Background Art

[0002] Currently, driven by environmental concerns, coal-fired power plants are urgently undergoing a coordinated "three reforms" program: coal-saving and energy-reduction retrofits, heating system upgrades, and flexibility upgrades tailored to their specific circumstances. As renewable energy sources continue to connect to the grid, coal-fired power plants, the primary source of peak load regulation, will increasingly shoulder these responsibilities. Therefore, proactively responding to the "three reforms" program and proactively planning the operational model for these units under these new circumstances is crucial for the survival of power generation companies.

[0003] Cogeneration, with its unique "temperature matching and cascaded utilization" approach, offers significant advantages in energy conservation and emission reduction, and is crucial for promoting the clean, low-carbon transformation of the power industry. For industrial heating, the current common approach is to use higher-energy extraction steam for heating, reducing temperature and pressure. However, this approach, which extracts steam from a higher-pressure or temperature point before cooling and reducing it for heat consumption, results in a degree of energy mismatch and waste, failing to truly achieve "temperature matching and cascaded utilization."

[0004] In addition, the technical route for flexibility transformation is divided into three aspects: optimization and adjustment, equipment transformation and thermoelectric decoupling. Among them, thermoelectric decoupling technology is further subdivided into improving steam parameter heating, electrode boilers, heat pump technology, low-pressure cylinder removal and thermal storage technology. Specifically, thermal storage technologies include hot water storage, ceramic storage, refractory brick storage and molten salt storage. However, there is no system in the existing technology that can achieve thermoelectric decoupling of heating / heat storage and power generation, which makes the coal-fired power units less flexible during operation, and thus cannot meet the increasingly frequent peak-shaving needs.

[0005] Therefore, there is an urgent need for a heat supply and heat storage system and method based on a pump-back machine, which can organically couple the heat supply transformation with the flexibility transformation to achieve energy level matching of the heat supply while improving the flexibility of the coal-fired power unit during operation. Summary of the Invention

[0006] In order to solve the problem in the prior art that there is a lack of an integrated system that can achieve heating energy level matching and thermal decoupling of heat storage and power generation, resulting in poor economic benefits of heating and an inability to meet the increasingly frequent peak-shaving needs, the present invention provides a heating and heat storage system and method based on a pump-back machine.

[0007] In order to achieve the above-mentioned object, the present invention provides a heat supply and heat storage system based on a back pumping machine in a first aspect, the system comprising a back pumping machine and a high-pressure cylinder;

[0008] The steam inlets of the back pump and the high-pressure cylinder are both connected to the main steam pipeline of the boiler, the steam extraction port of the back pump is connected to the high-pressure heating reheater inside the boiler, the high-pressure heating reheater is connected to the II-level heat storage heat exchanger, the II-level heat storage heat exchanger is respectively connected to the high-pressure heating header and the deaerator, the steam exhaust port of the back pump is connected to the medium-pressure heating reheater inside the boiler, the medium-pressure heating reheater is connected to the steam cooler, the steam cooler is respectively connected to the medium-pressure heating header and the II-level heat storage heat exchanger. The exhaust port of the high-pressure cylinder is connected to the reheat heater inside the boiler, the reheat heater, the intermediate-pressure cylinder and the low-pressure cylinder are connected in sequence, the exhaust port of the intermediate-pressure cylinder is connected to the I-stage heat storage heat exchanger, the I-stage heat storage heat exchanger is connected to the deaerator, the I-stage heat storage heat exchanger, the II-stage heat storage heat exchanger, the hot molten salt tank, the steam generator and the cold molten salt tank are connected end to end in sequence, an output end of the steam generator is respectively connected to the intermediate-pressure heating header and the low-pressure cylinder, and an input end is connected to the deaerator;

[0009] The exhaust port of the high-pressure cylinder is connected to the steam inlet of the high-pressure heating reheater, the steam outlet of the high-pressure heating reheater is connected to the steam inlet of the medium-pressure heating reheater, and the steam outlet of the medium-pressure heating reheater is connected to the steam inlet of the reheat heater.

[0010] Preferably, a high-pressure bypass valve is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the high-pressure heating reheater, a first medium-pressure bypass valve is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater and the steam inlet of the medium-pressure heating reheater, and a second medium-pressure bypass valve is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater and the steam inlet of the reheat heater.

[0011] Preferably, a steam inlet valve is provided on the connecting pipeline between the main steam pipeline of the boiler and the steam inlet of the back-up pump, a steam extraction valve is provided on the connecting pipeline between the steam extraction port of the back-up pump and the steam inlet of the high-pressure heating reheater, and a check valve and a stop valve are provided in sequence on the connecting pipeline between the steam exhaust port of the back-up pump and the steam inlet of the medium-pressure heating reheater;

[0012] A high-pressure shut-off valve is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the reheat heater.

[0013] Preferably, a heat storage steam inlet valve is provided on the connecting pipeline between the steam outlet of the high-pressure heat supply reheater and the steam inlet of the II-stage heat storage heat exchanger, and a heat storage steam outlet valve and a high-pressure header valve are provided in sequence on the connecting pipeline between the steam outlet of the II-stage heat storage heat exchanger and the high-pressure heat supply manifold.

[0014] Preferably, a first cooling valve is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater and the steam cooler, and a second cooling valve and a medium-pressure header valve are provided in sequence on the connecting pipeline between the steam cooler and the medium-pressure heating manifold;

[0015] The steam cooler is connected to the steam inlet of the II-stage heat storage heat exchanger via a pipeline, and a heat storage bypass valve is provided on the pipeline.

[0016] Preferably, the stage II heat storage heat exchanger and the deaerator are connected via a pipeline, and a second heat storage stop valve is provided on the pipeline.

[0017] Preferably, a heat storage drain valve, a drain recovery pump and a first heat storage stop valve are sequentially provided on the connecting pipeline between the I-stage heat storage heat exchanger and the deaerator.

[0018] Preferably, a deaerator valve, a deaerator outlet pump and a steam generator valve are sequentially provided on the connecting pipeline between the deaerator and the steam generator.

[0019] Preferably, a steam outlet valve and a medium-pressure heating valve are sequentially provided on the connecting pipeline between the steam outlet of the steam generator and the medium-pressure heating manifold;

[0020] A low-pressure cylinder steam supplement valve is provided on the connecting pipeline between the steam outlet of the steam generator and the low-pressure cylinder.

[0021] Preferably, a feed water pump, a high pressure heater and a three-way valve are sequentially provided on the connecting pipeline between the deaerator and the steam cooler, and the three-way valve and one output end of the steam cooler are both connected to the boiler low-temperature economizer.

[0022] Preferably, binary molten salt is provided in the cold molten salt tank, and the binary molten salt contains sodium nitrate and potassium nitrate, and the mass percentage of sodium nitrate and potassium nitrate is 60%:40%.

[0023] Preferably, the exhaust port of the intermediate pressure cylinder and the I-stage heat storage heat exchanger are connected via a pipeline, and a I-stage heat storage steam inlet valve is provided on the pipeline;

[0024] The medium-pressure cylinder and the low-pressure cylinder are connected via a pipeline, and a medium- and low-pressure cylinder connecting pipe butterfly valve is provided on the pipeline.

[0025] A second aspect of the present invention provides a heat supply and heat storage method based on a back pump, which is implemented using the above-mentioned heat supply and heat storage system based on a back pump, and the method comprises:

[0026] When in the heating mode, the main steam of the boiler enters the back-up machine all the way, and the back-up machine uses the main steam to generate electricity while transporting the high-pressure heating extraction steam and the medium-pressure heating exhaust steam to the high-pressure heating reheater and the medium-pressure heating reheater for heating, so as to obtain the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam, and then transport the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam to the II-level heat storage heat exchanger and the steam cooler for heat exchange and cooling, so as to obtain the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature, and then transport the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature to the high-pressure heating header and the medium-pressure heating header for heating;

[0027] The main steam of the boiler enters the high-pressure cylinder through another route. While the high-pressure cylinder uses the main steam to generate electricity, the high-pressure cylinder exhaust steam is transported to the reheat heater for heating, and the heated high-pressure cylinder exhaust steam is transported to the intermediate-pressure cylinder. While the intermediate-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the intermediate-pressure cylinder exhaust steam is transported to the first-stage heat storage heat exchanger for heat exchange and cooling, and / or transported to the low-pressure cylinder for power generation. Then, the drain formed after heat exchange and cooling in the first-stage heat storage heat exchanger is transported to the deaerator for recovery.

[0028] Among them, the heat absorbed through heat exchange in the II-level heat storage heat exchanger and the I-level heat storage heat exchanger is recovered through the cold molten salt tank and stored in the hot molten salt tank, and the heat stored in the hot molten salt tank is used by the steam generator to generate electricity in the low-pressure cylinder and / or to heat the medium-pressure heating manifold.

[0029] Preferably, when in condensing mode, main steam from the boiler enters the high-pressure cylinder, and while the high-pressure cylinder generates electricity, the high-pressure cylinder exhaust steam is sequentially transported to the high-pressure heat supply reheater and the medium-pressure heat supply reheater, and then the high-pressure cylinder exhaust steam output from the medium-pressure heat supply reheater is transported through the steam cooler to the II-stage heat storage heat exchanger for heat exchange and cooling, and the drain formed after heat exchange and cooling in the II-stage heat storage heat exchanger is transported to the deaerator for recovery; and the high-pressure cylinder exhaust steam is transported through the reheat heater to the intermediate-pressure cylinder, and while the intermediate-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the intermediate-pressure cylinder exhaust steam is transported to the I-stage heat storage heat exchanger for heat exchange and cooling / or to the low-pressure cylinder for power generation, and the drain formed after heat exchange and cooling in the I-stage heat storage heat exchanger is transported to the deaerator for recovery;

[0030] The heat absorbed by the heat exchange in the II-stage heat storage heat exchanger and the I-stage heat storage heat exchanger is recovered through the cold molten salt tank and stored in the hot molten salt tank, and the heat stored in the hot molten salt tank is used by the steam generator to generate electricity in the low-pressure cylinder.

[0031] Preferably, the thermal storage power is 10-100 MW.

[0032] According to the above technical solution, based on the heat supply and heat storage system of the back-pump machine, in actual application, by setting the steam extraction port of the back-pump machine to be connected with the high-pressure heat supply reheater inside the boiler, the high-pressure heat supply reheater is connected with the II-level heat storage heat exchanger, and the II-level heat storage heat exchanger is connected with the high-pressure heat supply header; and the steam exhaust port of the back-pump machine is connected with the medium-pressure heat supply reheater inside the boiler, the medium-pressure heat supply reheater is connected with the steam cooler, and the steam cooler is connected with the medium-pressure heat supply header; thus, on the basis of the back-pump machine, based on the high-pressure heat supply reheater and the medium-pressure heat supply reheater inside the boiler The device heats the high-pressure extraction steam and the medium-pressure exhaust steam to the set temperature respectively, which meets the demand for combined heating of high and medium pressures, realizes energy level matching heating, improves energy utilization, and avoids the solution of adopting boiler main steam heating in the existing technology; and by arranging the I-level heat storage heat exchanger to be connected with the medium-pressure cylinder, the I-level heat storage heat exchanger, the II-level heat storage heat exchanger, the hot molten salt tank, the steam generator and the cold molten salt tank are connected end to end in sequence, and the high-pressure extraction steam and the medium-pressure cylinder exhaust steam are used as heat storage sources to realize thermoelectric decoupling, which can effectively improve the flexibility of the coal-fired power unit, thereby effectively meeting the increasingly frequent peak-shaving needs.

[0033] At the same time, a high-pressure bypass valve is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the high-pressure heating reheater, a first medium-pressure bypass valve is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater and the steam inlet of the medium-pressure heating reheater, and a second medium-pressure bypass valve is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater and the steam inlet of the reheat heater. Therefore, in actual application, when there is no need to operate the pump-back machine to heat the high-pressure heating manifold and the medium-pressure heating manifold, the high-pressure cylinder exhaust steam can be introduced into the high-pressure heating reheater and the medium-pressure heating reheater for cooling by soft switching, so as to avoid dry burning of the high-pressure heating reheater and the medium-pressure heating reheater, which may cause risky operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural diagram of the heating mode of the heat supply and heat storage system based on the pump-back machine;

[0035] Figure 2 It is a structural diagram of the pure condensing mode of the heat supply and heat storage system based on the pump-back machine.

[0036] Description of Reference Numerals

[0037] Steam inlet valve 1; check valve 2; stop valve 3; steam extraction valve 4; first medium-pressure bypass valve 5;

[0038] High-pressure heating reheater 6; medium-pressure heating reheater 7; reheat heater 8; high-pressure stop valve 9;

[0039] High-pressure bypass valve 10; second medium-pressure bypass valve 11; first cooling valve 12; economizer valve 13;

[0040] Second cooling valve 14; three-way valve 15; II-stage heat storage steam inlet valve 16; heat storage bypass valve 17;

[0041] II-stage heat storage heat exchanger 18; II-stage heat storage steam outlet valve 19; high-pressure header valve 20;

[0042] Medium pressure header valve 21; I-stage heat storage steam inlet valve 22; I-stage heat storage heat exchanger 23; cold salt circulation pump 24;

[0043] Hot salt circulation pump 25; steam generator 26; thermal storage steam trap 27; steam recovery pump 28;

[0044] First heat storage stop valve 29; deaerator valve 30; deaerator outlet pump 31; steam generator valve 32;

[0045] Steam outlet valve 33; medium pressure heating valve 34; low pressure cylinder steam supply valve 35;

[0046] Butterfly valve 36 of the medium and low pressure cylinder connecting pipe; second heat storage stop valve 37. DETAILED DESCRIPTION

[0047] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0048] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate relative importance or implicitly specify the quantity of the technical features indicated. Therefore, unless otherwise specified, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features; "plurality" means two or more. The term "comprising" and any variations thereof are intended to imply the non-exclusive inclusion, possible presence, or addition of one or more other features, units, components, and / or combinations thereof.

[0049] Furthermore, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly, and may refer to, for example, fixed, removable, or ground connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0050] The first aspect of the present invention provides a heat supply and heat storage system based on a pumping machine, such as Figure 1-2 As shown, the heat supply and heat storage system based on the back pump includes a back pump and a high-pressure cylinder;

[0051] The steam inlets of the back pump and the high-pressure cylinder are both connected to the main steam pipeline of the boiler. The steam extraction port of the back pump is connected to the high-pressure heating reheater 6 inside the boiler. The high-pressure heating reheater 6 is connected to the II-level heat storage heat exchanger 18. The II-level heat storage heat exchanger 18 is respectively connected to the high-pressure heating header and the deaerator. The steam exhaust port of the back pump is connected to the medium-pressure heating reheater 7 inside the boiler. The medium-pressure heating reheater 7 is connected to the steam cooler. The steam cooler is respectively connected to the medium-pressure heating header and the II-level heat storage heat exchanger 18. The exhaust port of the high-pressure cylinder is connected to the reheat heater 8 inside the boiler, and the reheat heater 8, the medium-pressure cylinder and the low-pressure cylinder are connected in sequence. The exhaust port of the medium-pressure cylinder is connected to the I-stage heat storage heat exchanger 23, and the I-stage heat storage heat exchanger 23 is connected to the deaerator. The I-stage heat storage heat exchanger 23, the II-stage heat storage heat exchanger 18, the hot molten salt tank, the steam generator 26 and the cold molten salt tank are connected end to end in sequence. An output end of the steam generator 26 is respectively connected to the medium-pressure heating header and the low-pressure cylinder, and an input end is connected to the deaerator;

[0052] The exhaust port of the high-pressure cylinder is connected to the steam inlet of the high-pressure heating reheater 6, the steam outlet of the high-pressure heating reheater 6 is connected to the steam inlet of the medium-pressure heating reheater 7, and the steam outlet of the medium-pressure heating reheater 7 is connected to the steam inlet of the reheat heater 8.

[0053] In the present invention, the steam source for the backflow pump is specifically taken from the main steam of the boiler superheater. The main steam flowing through the backflow pump generates electricity that can be used to power the auxiliary equipment of the power plant, reducing the power consumption rate of the power plant. The extraction steam and exhaust steam of the backflow pump can be used as the steam source for high-pressure heating and medium-pressure heating, respectively. Furthermore, under normal circumstances, the efficiency of the backflow pump is 70-85%, which results in the extraction steam and exhaust steam temperatures of the backflow pump being relatively low, failing to meet the temperature requirements of high- and medium-pressure heating. Therefore, the present invention provides a high-pressure heating reheater 6 and a medium-pressure heating reheater 7 in the boiler to heat the extraction steam and exhaust steam of the backflow pump. The high-pressure heating steam and the medium-pressure heating steam that recover the boiler heat are respectively heated by the second-stage heat storage heat exchanger 18 and the steam cooler to heat the molten salt and boiler feed water. While increasing the temperature of the molten salt and boiler feed water, the temperature of the high-pressure heating steam and the medium-pressure heating steam are reduced to the corresponding heating demand temperature without the need for water spraying for cooling, thereby achieving energy level matching of the heating supply of the high-pressure heating header and the medium-pressure heating header. The high-pressure and medium-pressure heating headers facilitate the uniform mixing of steam at different pressures and temperatures. They also buffer pressure and temperature fluctuations in the heating piping system during heat load changes, preventing direct heat transfer to users. The steam cooler is a surface heat exchanger, with steam located in the shell side and feedwater located in the tube side. The steam cooler cools the medium-pressure heating steam, heated by the medium-pressure reheater 7, to the required heating temperature, reducing the amount of water spray required for cooling. Furthermore, it raises the feedwater temperature to improve the efficiency of the Rankine cycle.

[0054] According to the above technical solution, based on the heat supply and heat storage system of the back-pump machine, in actual application, by setting the steam extraction port of the back-pump machine to be connected with the high-pressure heat supply reheater inside the boiler, the high-pressure heat supply reheater is connected with the II-level heat storage heat exchanger, and the II-level heat storage heat exchanger is connected with the high-pressure heat supply header; and the steam exhaust port of the back-pump machine is connected with the medium-pressure heat supply reheater inside the boiler, the medium-pressure heat supply reheater is connected with the steam cooler, and the steam cooler is connected with the medium-pressure heat supply header; thus, on the basis of the back-pump machine, based on the high-pressure heat supply reheater and the medium-pressure heat supply reheater inside the boiler The device heats the high-pressure extraction steam and the medium-pressure exhaust steam to the set temperature respectively, which meets the demand for combined heating of high and medium pressures, realizes energy level matching heating, improves energy utilization, and avoids the solution of adopting boiler main steam heating in the existing technology; and by arranging the I-level heat storage heat exchanger to be connected with the medium-pressure cylinder, the I-level heat storage heat exchanger, the II-level heat storage heat exchanger, the hot molten salt tank, the steam generator and the cold molten salt tank are connected end to end in sequence, and the high-pressure extraction steam and the medium-pressure cylinder exhaust steam are used as heat storage sources to realize thermoelectric decoupling, which can effectively improve the flexibility of the coal-fired power unit, thereby effectively meeting the increasingly frequent peak-shaving needs.

[0055] In a preferred embodiment of the heat supply and heat storage system based on the pump-back machine described in the present invention, a high-pressure bypass valve 10 is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the high-pressure heating reheater 6, a first medium-pressure bypass valve 5 is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater 6 and the steam inlet of the medium-pressure heating reheater 7, and a second medium-pressure bypass valve 11 is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater 7 and the steam inlet of the reheat heater 8.

[0056] In the embodiment of the present invention, in the actual application process, when it is not necessary to operate the pump back machine to supply heat to the high pressure heating header and the medium pressure heating header, a soft switching method can be used, such as Figure 2 As shown, the high-pressure cylinder exhaust steam is introduced into the high-pressure heating reheater 6 and the medium-pressure heating reheater 7 to cool the high-pressure heating reheater 6 and the medium-pressure heating reheater 7 to avoid dry burning of the high-pressure heating reheater 6 and the medium-pressure heating reheater 7, which may lead to risky operation of the system.

[0057] In a preferred embodiment of the heat supply and heat storage system based on the back-up pump described in the present invention, a steam inlet valve 1 is provided on the connecting pipeline between the main steam pipeline of the boiler and the steam inlet of the back-up pump, a steam extraction valve 4 is provided on the connecting pipeline between the steam extraction port of the back-up pump and the steam inlet of the high-pressure heating reheater 6, a check valve 2 and a stop valve 3 are provided in sequence on the connecting pipeline between the exhaust port of the back-up pump and the steam inlet of the medium-pressure heating reheater 7; a high-pressure stop valve 9 is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the reheat heater 8.

[0058] In a more preferred embodiment, a Stage II thermal storage steam inlet valve 16 is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater 6 and the steam inlet of the Stage II thermal storage heat exchanger 18. A Stage II thermal storage steam outlet valve 19 and a high-pressure header valve 20 are sequentially provided on the connecting pipeline between the steam outlet of the Stage II thermal storage heat exchanger 18 and the high-pressure heating manifold. A first cooling valve 12 is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater 7 and the steam cooler. A second cooling valve 14 and a medium-pressure header valve 21 are sequentially provided on the connecting pipeline between the steam cooler and the medium-pressure heating manifold. The steam cooler is connected to the steam inlet of the Stage II thermal storage heat exchanger 18 via a pipeline, and a thermal storage bypass valve 17 is provided on that pipeline.

[0059] Further in a more preferred embodiment, the II-stage heat storage heat exchanger 18 is connected to the deaerator through a pipeline, and a second heat storage stop valve 37 is provided on the pipeline, so that when the back-up machine is not put into use (i.e., pure condensation mode), the heat of the high-pressure cylinder exhaust steam can be stored through the II-stage heat storage heat exchanger 18, and the hydrophobic water can be transported to the deaerator for recovery.

[0060] In the embodiment of the present invention, in actual application, the energy level matching heating of the high-pressure heating header and the medium-pressure heating header can be achieved by adjusting the valve opening and closing of the corresponding valve according to the actual heating needs. As for the specific valve setting position and number, they are not limited to the following. Figure 1 and 2 As shown, the same effect can be achieved. Figure 1 and Figure 2 The color of the middle valve indicates the open or closed state, white represents conduction and black represents blockage.

[0061] In a preferred embodiment of the heat supply and heat storage system based on the pump-back machine described in the present invention, a heat storage drain valve 27, a drain recovery pump 28 and a first heat storage stop valve 29 are sequentially provided on the connecting pipeline between the I-stage heat storage heat exchanger 23 and the deaerator.

[0062] In an embodiment of the present invention, by arranging the I-stage heat storage heat exchanger 23 to be connected to the deaerator, the exhaust steam of the intermediate pressure cylinder can be condensed and heat exchanged in the I-stage heat storage heat exchanger 23, and the formed hydrophobic water can be transported to the deaerator for recovery through the hydrophobic water recovery pump 28.

[0063] In a more preferred embodiment, the connecting pipeline between the deaerator and the steam generator 26 is sequentially provided with a deaerator valve 30, a deaerator outlet pump 31, and a steam generator valve 32. The connecting pipeline between the deaerator and the steam cooler is sequentially provided with a feedwater pump, a high-pressure heater, and a three-way valve 15. The three-way valve 15 and one output end of the steam cooler are both connected to the boiler's low-temperature economizer. The connecting pipeline between the steam outlet of the steam generator 26 and the medium-pressure heating manifold is sequentially provided with a steam outlet valve 33 and a medium-pressure heating valve 34. The connecting pipeline between the steam outlet of the steam generator 26 and the low-pressure cylinder is provided with a low-pressure cylinder steam replenishment valve 35.

[0064] In an embodiment of the present invention, the hydrophobic water with a certain temperature transported to the deaerator can be transported to the steam generator 26 to absorb heat and become steam under the action of the deaerator according to actual needs, and further used to heat the medium-pressure heating manifold and / or to generate electricity for the low-pressure cylinder according to actual needs. Specifically, when the medium-pressure heating reheater 7 cannot meet the heating demand of the medium-pressure heating manifold, dynamic supplementary heating is performed, and when the power generation needs to be increased, it is used to generate electricity for the low-pressure cylinder; one way can be directly transported to the boiler low-temperature economizer after preliminary heating in the high-pressure heater, or transported to the boiler low-temperature economizer after absorbing heat and heating in the steam cooler, thereby realizing full utilization of energy.

[0065] In a preferred embodiment of the heat supply and heat storage system based on the pump-back machine described in the present invention, binary molten salt is provided in the cold molten salt tank, and the binary molten salt contains sodium nitrate and potassium nitrate, and the mass percentage of sodium nitrate and potassium nitrate is 60%:40%. Therefore, in actual application, the heat absorbed by the heat exchange of the stage I heat storage heat exchanger 23 and the stage II heat storage heat exchanger 18 can be effectively stored and released through the steam generator 26, thereby better realizing thermoelectric decoupling.

[0066] In a preferred embodiment of the heat supply and heat storage system based on the pump-back machine described in the present invention, the exhaust port of the intermediate pressure cylinder and the first-stage heat storage heat exchanger 23 are connected by a pipeline, and a first-stage heat storage steam inlet valve 22 is provided on the pipeline; the intermediate pressure cylinder and the low pressure cylinder are connected by a pipeline, and a butterfly valve 36 for the intermediate and low pressure cylinder connecting pipe is provided on the pipeline.

[0067] A second aspect of the present invention further provides a heat supply and heat storage method based on a back pump, which is implemented using the above-mentioned heat supply and heat storage system based on a back pump, and the method comprises:

[0068] When in the heating mode, the main steam of the boiler enters the pump-back machine all the way. While using the main steam to generate electricity, the pump-back machine transports the high-pressure heating extraction steam and the medium-pressure heating exhaust steam to the high-pressure heating reheater 6 and the medium-pressure heating reheater 7 for heating, so as to obtain the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam. Then, the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam are respectively transported to the II-level heat storage heat exchanger 18 and the steam cooler for heat exchange and cooling, so as to obtain the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature. Then, the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature are respectively transported to the high-pressure heating header and the medium-pressure heating header for heating;

[0069] The main steam of the boiler enters the high-pressure cylinder through another route. While the high-pressure cylinder uses the main steam to generate electricity, the high-pressure cylinder exhaust steam is transported to the reheat heater 8 for heating, and the heated high-pressure cylinder exhaust steam is transported to the intermediate-pressure cylinder. While the intermediate-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the intermediate-pressure cylinder exhaust steam is transported to the first-stage heat storage heat exchanger 23 for heat exchange and cooling, and / or transported to the low-pressure cylinder for power generation. Then, the drain formed after heat exchange and cooling in the first-stage heat storage heat exchanger 23 is transported to the deaerator for recovery.

[0070] Among them, the heat absorbed through heat exchange in the II-level heat storage heat exchanger 18 and the I-level heat storage heat exchanger 23 is recovered through the cold molten salt tank and stored in the hot molten salt tank, and the heat stored in the hot molten salt tank is used for generating electricity in the low-pressure cylinder and / or heating the medium-pressure heating manifold through the steam generator 26.

[0071] In the embodiment of the present invention, based on the method of the present invention, in the heating mode, the thermal storage power is 10-100MW, which greatly improves the flexibility of the coal-fired power unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs.

[0072] The heat supply and heat storage method based on the pump-back machine described in the present invention, in a preferred embodiment, when in the condensing mode, the specific execution process is that the main steam of the boiler enters the high-pressure cylinder, and the high-pressure cylinder opens the high-pressure bypass valve 10 and the first medium-pressure bypass valve 5 while generating electricity, and the high-pressure cylinder exhaust steam is transported to the high-pressure heating reheater 6 and the medium-pressure heating reheater 7 in sequence, and then the second medium-pressure bypass valve 11, the first cooling valve 12, the second cooling valve 14 and the heat storage bypass valve 17 are opened, and the high-pressure cylinder exhaust steam output from the medium-pressure heating reheater 7 is transported all the way through the steam cooler to the II-level heat storage heat exchanger 18 for heat exchange and cooling, and the II-level heat storage steam outlet valve 19 and the first medium-pressure bypass valve 11 are opened. The second heat storage stop valve 37 conveys the drain formed after heat exchange and cooling in the II-stage heat storage heat exchanger 18 to the deaerator for recovery; one path is conveyed to the intermediate-pressure cylinder through the reheat heater 8. While the intermediate-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the opening and closing of the I-stage heat storage steam inlet valve 22 and the butterfly valve 36 of the intermediate- and low-pressure cylinder connecting pipe are controlled to convey the intermediate-pressure cylinder exhaust steam to the I-stage heat storage heat exchanger 23 for heat exchange and cooling / or to the low-pressure cylinder for power generation. The heat storage drain valve 27 and the first heat storage stop valve 29 are opened, and the drain recovery pump 28 is started to convey the drain formed after heat exchange and cooling in the I-stage heat storage heat exchanger 23 to the deaerator for recovery;

[0073] Among them, the heat absorbed through heat exchange in the II-level heat storage heat exchanger 18 and the I-level heat storage heat exchanger 23 is recovered through the cold molten salt tank and stored in the hot molten salt tank. By controlling the opening and closing of the steam outlet valve 33 and the low-pressure cylinder steam supplement valve 35, the heat stored in the hot molten salt tank can be used for power generation in the low-pressure cylinder through the steam generator 26.

[0074] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0075] Example 1

[0076] Taking the supercritical 670MW unit as an example, the technical boundary parameters are: pipeline efficiency is 99%, boiler efficiency is 94.5%, auxiliary power rate is 4.5%, molten salt thermal storage comprehensive thermal efficiency is 80% (taking into account the power consumption of the circulating pump), at a main steam flow of 50% THA (i.e. 335MW), and the exhaust steam flow from the intermediate pressure cylinder to the I-stage heat storage heat exchanger 23 is 0t / h. Figure 1 As shown, the heat supply and heat storage system based on the back pumping machine of the present invention is implemented. Specifically, the system includes a back pumping machine and a high-pressure cylinder;

[0077] The steam inlets of the back pump and the high-pressure cylinder are both connected to the main steam pipeline of the boiler. The steam extraction port of the back pump is connected to the high-pressure heating reheater 6 inside the boiler. The high-pressure heating reheater 6 is connected to the II-level heat storage heat exchanger 18. The II-level heat storage heat exchanger 18 is respectively connected to the high-pressure heating header and the deaerator. The steam exhaust port of the back pump is connected to the medium-pressure heating reheater 7 inside the boiler. The medium-pressure heating reheater 7 is connected to the steam cooler. The steam cooler is respectively connected to the medium-pressure heating header and the II-level heat storage heat exchanger 18. The exhaust port of the high-pressure cylinder is connected to the reheat heater 8 inside the boiler, and the reheat heater 8, the medium-pressure cylinder and the low-pressure cylinder are connected in sequence. The exhaust port of the medium-pressure cylinder is connected to the I-stage heat storage heat exchanger 23, and the I-stage heat storage heat exchanger 23 is connected to the deaerator. The I-stage heat storage heat exchanger 23, the II-stage heat storage heat exchanger 18, the hot molten salt tank, the steam generator 26 and the cold molten salt tank are connected end to end in sequence. An output end of the steam generator 26 is respectively connected to the medium-pressure heating manifold and the low-pressure cylinder, and an input end is connected to the deaerator.

[0078] Specifically, a high-pressure bypass valve 10 is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the high-pressure heating reheater 6, a first medium-pressure bypass valve 5 is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater 6 and the steam inlet of the medium-pressure heating reheater 7, and a second medium-pressure bypass valve 11 is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater 7 and the steam inlet of the reheat heater 8;

[0079] A steam inlet valve 1 is provided on the connecting pipeline between the main steam pipeline of the boiler and the steam inlet of the back-up pumping machine, a steam extraction valve 4 is provided on the connecting pipeline between the steam extraction port of the back-up pumping machine and the steam inlet of the high-pressure heating reheater 6, a check valve 2 and a stop valve 3 are provided in sequence on the connecting pipeline between the exhaust port of the back-up pumping machine and the steam inlet of the medium-pressure heating reheater 7; a high-pressure stop valve 9 is provided on the connecting pipeline between the exhaust port of the high-pressure cylinder and the steam inlet of the reheat heater 8;

[0080] A second-stage heat storage steam inlet valve 16 is provided on the connecting pipe between the steam outlet of the high-pressure heating reheater 6 and the steam inlet of the second-stage heat storage heat exchanger 18. A second-stage heat storage steam outlet valve 19 and a high-pressure header valve 20 are provided in sequence on the connecting pipe between the steam outlet of the second-stage heat storage heat exchanger 18 and the high-pressure heating header.

[0081] A first cooling valve 12 is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater 7 and the steam cooler, and a second cooling valve 14 and a medium-pressure header valve 21 are provided in sequence on the connecting pipeline between the steam cooler and the medium-pressure heating manifold. The steam cooler is connected to the steam inlet of the II-stage heat storage heat exchanger 18 via a pipeline, and a heat storage bypass valve 17 is provided on the pipeline.

[0082] The II-stage heat storage heat exchanger 18 is connected to the deaerator via a pipeline, and a second heat storage stop valve 37 is provided on the pipeline;

[0083] The connecting pipeline between the first-stage heat storage heat exchanger 23 and the deaerator is provided with a heat storage drain valve 27, a drain recovery pump 28 and a first heat storage stop valve 29 in sequence;

[0084] The connecting pipeline between the deaerator and the steam generator 26 is provided with a deaerator valve 30, a deaerator outlet pump 31 and a steam generator valve 32 in sequence;

[0085] A steam outlet valve 33 and a medium-pressure heating valve 34 are sequentially provided on the connecting pipeline between the steam outlet of the steam generator 26 and the medium-pressure heating manifold;

[0086] A low-pressure cylinder steam supplement valve 35 is provided on the connecting pipeline between the steam outlet of the steam generator 26 and the low-pressure cylinder;

[0087] A feed water pump, a high pressure heater and a three-way valve 15 are sequentially provided on the connecting pipeline between the deaerator and the steam cooler. The three-way valve 15 and one output end of the steam cooler are both connected to the low-temperature economizer of the boiler.

[0088] The cold molten salt tank is provided with binary molten salt, wherein the binary molten salt contains sodium nitrate and potassium nitrate, and the mass percentage of sodium nitrate and potassium nitrate is 60%:40%;

[0089] The exhaust port of the intermediate pressure cylinder is connected to the first-stage heat storage heat exchanger 23 via a pipeline, and a first-stage heat storage steam inlet valve 22 is provided on the pipeline;

[0090] The medium-pressure cylinder and the low-pressure cylinder are connected via a pipeline, and a medium- and low-pressure cylinder connecting pipe butterfly valve 36 is provided on the pipeline.

[0091] In actual application, when in heating mode, the steam inlet valve 1 is opened, and the main steam of the boiler enters the extraction machine all the way. While the extraction machine uses the main steam to generate electricity, it opens the extraction valve 4, the check valve 2 and the stop valve 3 to respectively transport the high-pressure heating extraction steam and the medium-pressure heating exhaust steam to the high-pressure heating reheater 6 and the medium-pressure heating reheater 7 for heating, so as to obtain the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam. Then, the II-level heat storage steam inlet valve 16 and the first cooling valve 12 are opened. The high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heating are respectively transported to the II-stage heat storage heat exchanger 18 and the steam cooler for heat exchange and cooling, so as to obtain the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature. Then, the II-stage heat storage steam outlet valve 19 and the high-pressure header valve 20, as well as the second cooling valve 14 and the medium-pressure header valve 21 are opened, and the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature are respectively transported to the high-pressure heating header and the medium-pressure heating header for heating;

[0092] The boiler main steam enters the high-pressure cylinder through another route. The high-pressure stop valve 9 is opened. While the high-pressure cylinder uses the main steam to generate electricity, the high-pressure cylinder exhaust steam is transported to the reheat heater 8 for heating. The heated high-pressure cylinder exhaust steam is then transported to the intermediate-pressure cylinder. While the intermediate-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the opening and closing of the first-stage heat storage steam inlet valve 22 and the butterfly valve 36 connecting the intermediate and low-pressure cylinders are controlled to transport the intermediate-pressure cylinder exhaust steam to the first-stage heat storage heat exchanger 23 for heat exchange and cooling and / or to the low-pressure cylinder for power generation. Then, the heat storage drain valve 27 and the first heat storage stop valve 29 are opened, and the drain recovery pump 28 is started to transport the drain formed after heat exchange and cooling in the first-stage heat storage heat exchanger 23 to the deaerator for recovery.

[0093] Among them, the heat absorbed through heat exchange in the II-level heat storage heat exchanger 18 and the I-level heat storage heat exchanger 23 is recovered and stored in the hot molten salt tank based on the molten salt flow rate output by the cold molten salt tank, and by controlling the opening and closing of the steam outlet valve 33, the medium-pressure heating valve 34 and the low-pressure cylinder steam supplement valve 35, the heat stored in the hot molten salt tank can be used for low-pressure cylinder power generation and / or heating the medium-pressure heating manifold through the steam generator 26 and the deaerator.

[0094] After testing, it was found that the use of the heat supply and heat storage system based on the pump-back machine described in the present invention not only achieved the energy level matching of the high-pressure heating manifold and the medium-pressure heating manifold, but also the heat storage power reached 13.69MW, effectively improving the flexibility of the unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs, and having good economic benefits.

[0095] Example 2

[0096] The method is implemented with reference to Example 1, except that, in Example 2, the exhaust steam flow rate from the intermediate pressure cylinder to the stage I heat storage heat exchanger 23 is 25 t / h.

[0097] After testing, it was found that the use of the heat supply and heat storage system based on the pump-back machine described in the present invention not only achieved the energy level matching of the high-pressure heating manifold and the medium-pressure heating manifold, but also the heat storage power reached 28.11MW, effectively improving the flexibility of the unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs, and having good economic benefits.

[0098] Example 3

[0099] The method is implemented with reference to Example 1, except that, in Example 3, the exhaust steam flow rate from the intermediate pressure cylinder to the stage I heat storage heat exchanger 23 is 50 t / h.

[0100] After testing, it was found that the use of the heat supply and heat storage system based on the pump-back machine described in the present invention not only achieved the energy level matching of the high-pressure heating manifold and the medium-pressure heating manifold, but also the heat storage power reached 42.46MW, effectively improving the flexibility of the unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs and having good economic benefits.

[0101] Example 4

[0102] The method is implemented with reference to Example 1, except that, in Example 4, the exhaust steam flow rate from the intermediate pressure cylinder to the stage I heat storage heat exchanger 23 is 75 t / h.

[0103] After testing, it was found that the use of the heat supply and heat storage system based on the pump-back machine described in the present invention not only achieved the energy level matching of the high-pressure heating manifold and the medium-pressure heating manifold, but also the heat storage power reached 56.75MW, effectively improving the flexibility of the unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs and having good economic benefits.

[0104] Example 5

[0105] The method is implemented with reference to Example 1, except that, in Example 5, the exhaust steam flow rate from the intermediate pressure cylinder to the stage I heat storage heat exchanger 23 is 100 t / h.

[0106] After testing, it was found that the use of the heat supply and heat storage system based on the pump-back machine described in the present invention not only achieved the energy level matching of the high-pressure heating manifold and the medium-pressure heating manifold, but also the heat storage power reached 70.97MW, effectively improving the flexibility of the unit operation, thereby effectively meeting the increasingly frequent peak-shaving needs, and having good economic benefits.

[0107] Furthermore, in order to illustrate Examples 1-5 in more detail, the relevant data are listed in the form of Table 1 below.

[0108] Table 1

[0109]

[0110]

[0111] Note: The heat consumption calculation has taken into account the power generation of the back pressure machine.

[0112] The present invention provides a heat supply and heat storage system and method based on a back-up machine, which is configured such that the steam extraction port of the back-up machine is connected to the high-pressure heat supply reheater inside the boiler, the high-pressure heat supply reheater is connected to the II-stage heat storage heat exchanger, and the II-stage heat storage heat exchanger is connected to the high-pressure heat supply header; and the steam exhaust port of the back-up machine is connected to the medium-pressure heat supply reheater inside the boiler, the medium-pressure heat supply reheater is connected to the steam cooler, and the steam cooler is connected to the medium-pressure heat supply header; thereby, on the basis of the back-up machine, the high-pressure heat supply reheater and the medium-pressure heat supply reheater inside the boiler are respectively connected to the high-pressure heat supply reheater. The high-pressure extraction steam and the medium-pressure exhaust steam are heated to the set temperature, which meets the demand for joint heating of high and medium pressures, realizes energy level matching heating, improves energy utilization, and avoids the scheme of adopting boiler main steam heating in the existing technology; and by arranging the I-level heat storage heat exchanger to be connected with the medium-pressure cylinder, the I-level heat storage heat exchanger, the II-level heat storage heat exchanger, the hot molten salt tank, the steam generator and the cold molten salt tank are connected end to end in sequence, and the high-pressure extraction steam and the medium-pressure cylinder exhaust steam are used as heat storage sources to realize thermoelectric decoupling, which can effectively improve the flexibility of the coal-fired power unit, thereby effectively meeting the increasingly frequent peak-shaving needs.

[0113] While the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited thereto. Within the technical scope of the present invention, various simple variations of the technical solution of the present invention may be made. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple variations and combinations should also be considered as disclosed herein and fall within the scope of protection of the present invention.

Claims

1. A heat supply and heat storage system based on a pumping machine, characterized in that: The heat supply and heat storage system based on the back pump includes a back pump and a high-pressure cylinder; The steam inlets of the back pump and the high-pressure cylinder are both connected to the main steam pipeline of the boiler, the steam extraction port of the back pump is connected to the high-pressure heat supply reheater (6) inside the boiler, the high-pressure heat supply reheater (6) is connected to the II-level heat storage heat exchanger (18), the II-level heat storage heat exchanger (18) is respectively connected to the high-pressure heat supply header and the deaerator, the steam exhaust port of the back pump is connected to the medium-pressure heat supply reheater (7) inside the boiler, the medium-pressure heat supply reheater (7) is connected to the steam cooler, the steam cooler is respectively connected to the medium-pressure heat supply header and the II-level heat storage heat exchanger (18), the The exhaust port of the high-pressure cylinder is connected to the reheat heater (8) inside the boiler, the reheat heater (8), the medium-pressure cylinder and the low-pressure cylinder are connected in sequence, the exhaust port of the medium-pressure cylinder is connected to the I-stage heat storage heat exchanger (23), the I-stage heat storage heat exchanger (23) is connected to the deaerator, the I-stage heat storage heat exchanger (23), the II-stage heat storage heat exchanger (18), the hot molten salt tank, the steam generator (26) and the cold molten salt tank are connected end to end in sequence, an output end of the steam generator (26) is respectively connected to the medium-pressure heating header and the low-pressure cylinder, and an input end is connected to the deaerator; The steam exhaust port of the high-pressure cylinder is connected to the steam inlet of the high-pressure heating reheater (6), the steam outlet of the high-pressure heating reheater (6) is connected to the steam inlet of the medium-pressure heating reheater (7), and the steam outlet of the medium-pressure heating reheater (7) is connected to the steam inlet of the reheat heater (8).

2. The heat supply and heat storage system based on the pumping machine according to claim 1 is characterized in that: A high-pressure bypass valve (10) is provided on the connecting pipeline between the steam exhaust port of the high-pressure cylinder and the steam inlet of the high-pressure heating reheater (6), a first medium-pressure bypass valve (5) is provided on the connecting pipeline between the steam outlet of the high-pressure heating reheater (6) and the steam inlet of the medium-pressure heating reheater (7), and a second medium-pressure bypass valve (11) is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater (7) and the steam inlet of the reheat heater (8).

3. The heat supply and heat storage system based on the pumping machine according to claim 1 is characterized in that: A steam inlet valve (1) is provided on the connecting pipeline between the main steam pipeline of the boiler and the steam inlet of the back-up machine, a steam extraction valve (4) is provided on the connecting pipeline between the steam extraction port of the back-up machine and the steam inlet of the high-pressure heating reheater (6), and a check valve (2) and a stop valve (3) are provided in sequence on the connecting pipeline between the steam exhaust port of the back-up machine and the steam inlet of the medium-pressure heating reheater (7); A high-pressure shut-off valve (9) is provided on the connecting pipeline between the steam exhaust port of the high-pressure cylinder and the steam inlet of the reheat heater (8).

4. The heat supply and heat storage system based on the pumping machine according to any one of claims 1 to 3, characterized in that: A second-stage heat storage steam inlet valve (16) is provided on the connecting pipeline between the steam outlet of the high-pressure heat supply reheater (6) and the steam inlet of the second-stage heat storage heat exchanger (18), and a second-stage heat storage steam outlet valve (19) and a high-pressure header valve (20) are provided in sequence on the connecting pipeline between the steam outlet of the second-stage heat storage heat exchanger (18) and the high-pressure heat supply header.

5. The heat supply and heat storage system based on the pumping machine according to claim 4 is characterized in that: A first cooling valve (12) is provided on the connecting pipeline between the steam outlet of the medium-pressure heating reheater (7) and the steam cooler, and a second cooling valve (14) and a medium-pressure header valve (21) are provided in sequence on the connecting pipeline between the steam cooler and the medium-pressure heating header. The steam cooler is connected to the steam inlet of the II-stage heat storage heat exchanger (18) via a pipeline, and a heat storage bypass valve (17) is provided on the pipeline.

6. The heat supply and heat storage system based on the pumping machine according to claim 5 is characterized in that: The II-stage heat storage heat exchanger (18) is connected to the deaerator via a pipeline, and a second heat storage stop valve (37) is provided on the pipeline.

7. The heat supply and heat storage system based on the pumping machine according to claim 1 is characterized in that: A heat storage drain valve (27), a drain recovery pump (28) and a first heat storage stop valve (29) are sequentially provided on the connecting pipeline between the first-stage heat storage heat exchanger (23) and the deaerator.

8. The heat supply and heat storage system based on the pumping machine according to claim 1 or 7, characterized in that: A deaerator valve (30), a deaerator outlet pump (31) and a steam generator valve (32) are sequentially arranged on the connecting pipeline between the deaerator and the steam generator (26).

9. The heat supply and heat storage system based on the pumping machine according to claim 1, characterized in that: A steam outlet valve (33) and a medium-pressure heating valve (34) are sequentially provided on the connecting pipeline between the steam outlet of the steam generator (26) and the medium-pressure heating header; A low-pressure cylinder steam supplement valve (35) is provided on the connecting pipeline between the steam outlet of the steam generator (26) and the low-pressure cylinder.

10. The heat supply and heat storage system based on the pumping machine according to claim 1, characterized in that: A feed water pump, a high pressure heater and a three-way valve (15) are sequentially arranged on the connecting pipeline between the deaerator and the steam cooler. The three-way valve (15) and an output end of the steam cooler are both connected to the boiler low-temperature economizer.

11. The heat supply and heat storage system based on the pumping machine according to claim 1, characterized in that: The cold molten salt tank is provided with binary molten salt, and the binary molten salt contains sodium nitrate and potassium nitrate, and the mass percentage of sodium nitrate and potassium nitrate is 60%:40%.

12. The heat supply and heat storage system based on the pumping machine according to claim 1, characterized in that: The exhaust port of the intermediate pressure cylinder and the first-stage heat storage heat exchanger (23) are connected via a pipeline, and a first-stage heat storage steam inlet valve (22) is provided on the pipeline; The medium-pressure cylinder and the low-pressure cylinder are connected via a pipeline, and a medium- and low-pressure cylinder connecting pipe butterfly valve (36) is provided on the pipeline.

13. A heat supply and heat storage method based on a back pump, implemented using the heat supply and heat storage system based on a back pump according to any one of claims 1 to 12, characterized in that: The method includes: When in the heating mode, the main steam of the boiler enters the pump-back machine all the way. The pump-back machine uses the main steam to generate electricity while transporting the high-pressure heating extraction steam and the medium-pressure heating exhaust steam to the high-pressure heating reheater (6) and the medium-pressure heating reheater (7) for heating to obtain the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam. Then, the heated high-pressure heating extraction steam and the medium-pressure heating exhaust steam are respectively transported to the II-level heat storage heat exchanger (18) and the steam cooler for heat exchange and cooling to obtain the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature. Then, the high-pressure heating extraction steam and the medium-pressure heating exhaust steam after heat exchange and cooling to the preset temperature are respectively transported to the high-pressure heating header and the medium-pressure heating header for heating. The main steam of the boiler enters the high-pressure cylinder through another path. The high-pressure cylinder, while using the main steam to generate electricity, transmits the high-pressure cylinder exhaust steam to the reheat heater (8) for heating, and transmits the heated high-pressure cylinder exhaust steam to the medium-pressure cylinder. The medium-pressure cylinder, while using the heated high-pressure cylinder exhaust steam to generate electricity, transmits the medium-pressure cylinder exhaust steam to the first-stage heat storage heat exchanger (23) for heat exchange and cooling and / or transmits it to the low-pressure cylinder for power generation. Then, the hydrophobic water formed after heat exchange and cooling in the first-stage heat storage heat exchanger (23) is transmitted to the deaerator for recovery. The heat absorbed by the heat exchange in the II-stage heat storage heat exchanger (18) and the I-stage heat storage heat exchanger (23) is recovered through the cold molten salt tank and stored in the hot molten salt tank, and the heat stored in the hot molten salt tank is used for generating electricity in the low-pressure cylinder and / or for heating the medium-pressure heating manifold through the steam generator (26).

14. The heat supply and heat storage method based on the back pump according to claim 13, characterized in that: When in condensing mode, the main steam of the boiler enters the high-pressure cylinder. While the high-pressure cylinder generates electricity, the high-pressure cylinder exhaust steam is sequentially transported to the high-pressure heat supply reheater (6) and the medium-pressure heat supply reheater (7). Then, the high-pressure cylinder exhaust steam output from the medium-pressure heat supply reheater (7) is transported to the II-stage heat storage heat exchanger (18) through the steam cooler for heat exchange and cooling, and the drain formed after heat exchange and cooling in the II-stage heat storage heat exchanger (18) is transported to the deaerator for recovery; and is transported to the medium-pressure cylinder through the reheat heater (8). While the medium-pressure cylinder uses the heated high-pressure cylinder exhaust steam to generate electricity, the medium-pressure cylinder exhaust steam is transported to the I-stage heat storage heat exchanger (23) for heat exchange and cooling and / or transported to the low-pressure cylinder for power generation, and the drain formed after heat exchange and cooling in the I-stage heat storage heat exchanger (23) is transported to the deaerator for recovery. The heat absorbed by the heat exchange in the II-stage heat storage heat exchanger (18) and the I-stage heat storage heat exchanger (23) is recovered through the cold molten salt tank and stored in the hot molten salt tank, and the heat stored in the hot molten salt tank is used to generate electricity in the low-pressure cylinder through the steam generator (26).

15. The heat supply and heat storage method based on the back pump according to claim 13, characterized in that: The thermal storage power is 10-100MW.

Images