Combined heat and power generation system and operation method thereof

Abstract

The invention relates to the technical field of combined heat and power generation. The invention discloses a combined heat and power generation system and an operation method thereof. The system comprises a low-temperature heat source, a heat pump, a heat exchanger and a heat storage structure. The heat pump is arranged on a heat supply pipeline, the low-temperature heat source is connected with the heat exchanger, a water side outlet of the heat exchanger is connected with an inlet of the heat pump through a first branch, and an outlet of the heat pump is connected with an inlet of the heat storage structure; the water side outlet of the heat exchanger is further connected with the inlet of the heat storage structure through a second branch, and the outlet of the heat storage structure is connected with the water side inlet of the heat exchanger or / and the inlet of the heat pump. The heat of the low-temperature heat source can be directly applied to the heat pump through the first branch, the heat of the low-temperature heat source can be stored in the heat storage structure through the second branch, and the heat of the low-temperature heat source is applied to the heat pump through the heat storage structure; and when the low-temperature heat source is an intermittent and / or unstable heat source, the energy utilization rate of the low-temperature heat source can also be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cogeneration of heat and power, and in particular to a cogeneration system and an operation method thereof. Background Art

[0002] At present, low-pressure cylinder zero-output or micro-output technology has become the first choice for flexibility transformation of cogeneration units. It has replaced waste heat utilization technologies such as heat pumps, low-pressure cylinder bare axes, and low-pressure cylinder double back-pressure double rotors, and has been increasingly widely developed and applied.

[0003] The low-pressure cylinder zero-output or micro-output technology essentially means that the steam turbine unit can switch between the extraction condensing mode and the low-pressure cylinder zero-output or micro-output operation mode at any time according to the thermal power load needs.

[0004] When the electrical load is low and the thermal load is high, the valves connecting the intermediate and low pressure cylinders of the steam turbine are closed. Except for a small amount (tens of tons per hour) of exhaust steam from the intermediate pressure cylinder that enters the low pressure cylinder for cooling, the rest is all used for heating. The steam turbine is in zero or micro output mode for the low pressure cylinder.

[0005] When the electrical load is high or the thermal load is not too high, the valves of the connecting pipes of the medium and low pressure cylinders are opened, and the unit returns to the extraction and condensing operation mode. In this operation mode, the exhaust volume of the low pressure cylinder of the steam turbine is large, resulting in huge low-temperature waste heat loss. When the electrical load is low or the thermal load is high, the valves of the connecting pipes of the medium and low pressure cylinders of the steam turbine are closed, and the unit operates in the low pressure cylinder zero output or micro output mode. Compared with the extraction and condensing operation mode, under the same electrical load, the heating capacity of the unit operating with the low pressure cylinder zero output is significantly improved, and the exhaust volume of the steam turbine is significantly reduced. Compared with the extraction and condensing operation mode, although the waste heat loss is significantly reduced, tens of tons of exhaust steam latent heat are still discharged into the atmosphere, which is wasted.

[0006] In view of the great difference between the steam turbine exhaust volume and the corresponding waste heat in the extraction condensing operation mode and the low-pressure cylinder zero output / micro output operation mode, the cogeneration units currently using the low-pressure cylinder zero output / micro output technology basically do not consider configuring waste heat utilization devices, and the exhaust steam heat is directly discharged, resulting in huge cold end losses. Therefore, how to recover the waste heat of this part of the exhaust steam has become a technical problem that needs to be solved urgently.

[0007] In addition, in order to increase the flexibility of the thermal and electric load regulation of some cogeneration units, heat storage devices are added. When the unit's electrical load is high, the surplus heating extraction steam is used to heat hot water and store it in the heat storage tank. When the electrical load is low and the heating extraction steam capacity is insufficient, the stored heat is used to compensate for part of the heating supply to meet user needs. However, in the actual production process, long-term (several days) low electrical load operation conditions often occur, and heat storage cannot be achieved, which loses the proper role of the heat storage device. Summary of the invention

[0008] In view of this, the present invention provides a cogeneration system and an operation method thereof.

[0009] Specifically, the following technical solutions are included:

[0010] In a first aspect, a cogeneration system is provided, comprising:

[0011] Low temperature heat source, heat pump, heat exchanger, heat storage structure;

[0012] The heat pump is arranged on the heating pipeline, the low-temperature heat source is connected to the heat exchanger, the water side outlet of the heat exchanger is connected to the inlet of the heat pump through the first branch, and the outlet of the heat pump is connected to the inlet of the heat storage structure;

[0013] The water side outlet of the heat exchanger is also connected to the inlet of the heat storage structure through a second branch, and the outlet of the heat storage structure is connected to the water side inlet of the heat exchanger or / and the inlet of the heat pump.

[0014] Preferably, the low-temperature heat source includes a steam turbine and / or a boiler.

[0015] Preferably, the low temperature heat source comprises a low pressure cylinder;

[0016] The heat exchanger is a condenser;

[0017] The cogeneration system also includes a medium-pressure cylinder and a heat network heater. The medium-pressure cylinder and the low-pressure cylinder are connected in an on-off manner. The low-pressure cylinder is connected to the heat exchanger. The medium-pressure cylinder is connected to the heat network heater. The heat pump is connected to the heat network heater.

[0018] Preferably, the heat storage structure includes a cooling tower pool.

[0019] Preferably, the outlet of the heat exchanger is also connected to the water distribution layer of the cooling tower through a third branch.

[0020] Preferably, the cogeneration system further comprises a circulating water pump;

[0021] The outlet of the heat storage structure and the water-side inlet of the heat exchanger are connected via a heat storage branch, and the circulating water pump is arranged on the heat storage branch.

[0022] Preferably, the cogeneration system further comprises a heating branch;

[0023] The inlet of the heat pump and the outlet of the circulating water pump are connected through the heating branch.

[0024] In a second aspect, a method for operating a cogeneration system is provided, which is applied to a cogeneration system as described in the first aspect, and the method comprises:

[0025] When the low-temperature heat source is in the first operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat pump through the first branch, and is used by the heat pump to heat the water in the heating pipeline, or,

[0026] Controlling a portion of the water flowing out of the water-side outlet of the heat exchanger to enter the inlet of the heat pump through the first branch, and to be used by the heat pump to heat the water in the heating pipeline, and another portion of the water flowing out of the water-side outlet of the heat exchanger to enter the inlet of the heat storage structure through the second branch, and to store heat in the heat storage structure;

[0027] When the low-temperature heat source is in the second operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat storage structure through the second branch, and heat is stored in the heat storage structure. The water in the heat storage structure enters the inlet of the heat pump and / or the water-side inlet of the heat exchanger from the outlet of the heat storage structure, and the heat stored in the heat storage structure is used by the heat pump to heat the water in the heating pipeline, or,

[0028] The water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat pump through the first branch, and is used by the heat pump to heat the water in the heating pipeline.

[0029] Preferably, the method further comprises:

[0030] When the temperature of the water in the heat storage structure is less than or equal to a first preset value, controlling a circulating water pump to drive the water in the heat storage structure to circulate between the heat exchanger and the heat storage structure;

[0031] When the temperature of the water in the heat storage structure is greater than or equal to a second preset value, the circulating water pump is controlled to drive the water in the heat storage structure to circulate between the heat exchanger, the cooling tower water distribution layer and the heat storage structure.

[0032] Preferably, the method further comprises:

[0033] When the heat of the low-temperature heat source is greater than the heat required by the heat pump and the temperature of the water in the heat storage structure is greater than or equal to a second preset value, the circulating water pump is controlled to drive the water after heat exchange in the heat exchanger to enter the cooling tower water distribution layer from the water side outlet through the third branch.

[0034] The beneficial effects of the technical solution provided by the present invention include at least:

[0035] The heat of the low-temperature heat source of the present application can be directly applied to the heat pump through the first branch, or the heat of the low-temperature heat source can be stored in the heat storage structure through the second branch. The heat in the low-temperature heat source can be applied to the heat pump through the heat storage structure. When the low-temperature heat source is an intermittent heat source, the energy utilization rate of the low-temperature heat source can be improved. The waste heat is stored and coupled with the heat pump technology for heating, which can simultaneously solve the problems of waste heat waste and the difficulty of conventional heat storage during long-term electric load operation, and has important engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A cogeneration system according to an embodiment of the present invention.

[0038] The reference numerals in the figures represent respectively:

[0039] 1-heat pump; 2-fourth valve; 3-first valve; 4-third valve; 5-second valve; 6-1-cooling tower water distribution layer; 6-2-cooling tower pool; 7-circulating water pump; 8-condenser; 9-low-pressure cylinder; 10-medium-pressure cylinder; 11-sixth valve; 12-heat network heater; 13-fifth valve.

[0040] The above drawings have shown clear embodiments of the present invention, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present invention in any way, but to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Before further describing the embodiments of the present invention in detail, the directional nouns involved in the embodiments of the present invention, such as "upper part", "lower part", "side part", etc., are Figure 1 The directions shown in the figure are for reference only and do not limit the protection scope of the present invention.

[0043] To make the technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0044] The present application provides a combined heat and power system, such as Figure 1 As shown, it includes: a low-temperature heat source, a heat pump 1, a heat exchanger, and a heat storage structure; the heat pump 1 is arranged on a heating pipeline, the low-temperature heat source is connected to the heat exchanger, the water side outlet of the heat exchanger is connected to the inlet of the heat pump 1 through a first branch, and the outlet of the heat pump 1 is connected to the inlet of the heat storage structure; the water side outlet of the heat exchanger is also connected to the inlet of the heat storage structure through a second branch, and the outlet of the heat storage structure is connected to the water side inlet of the heat exchanger or / and the inlet of the heat pump 1.

[0045] In the present application, the heat of the low-temperature heat source can be directly applied to the heat pump 1 through the first branch, or the heat of the low-temperature heat source can be stored in the heat storage structure through the second branch. The heat in the low-temperature heat source can be applied to the heat pump 1 through the heat storage structure, thereby improving the energy utilization rate of the low-temperature heat source. The first branch and the second branch can be used independently or in combination. When used independently, the heat of the low-temperature heat source only enters the heat pump 1 or only enters the heat storage structure. When used in combination, a part of the heat of the low-temperature heat source can be applied to the heat pump 1, and another part of the heat of the low-temperature heat source can enter the heat storage structure for storage. Figure 1 As shown, when the low-temperature heat source is the low-pressure cylinder 9, and the low-pressure cylinder 9 adopts the low-pressure cylinder 9 zero-output or low-pressure cylinder 9 micro-output technology, the heat in the discontinuous exhaust steam generated can also be recovered. When the exhaust steam is small, the heat in the exhaust steam is stored in the heat storage structure through the second branch, and the heat in the low-temperature heat source is applied to the heat pump 1 through the heat storage structure; when the exhaust steam is large, the heat in the low-temperature heat source is directly applied to the heat pump 1 through the first branch, or, a part of the heat in the low-temperature heat source is directly applied to the heat pump 1 through the first branch, and the other part of the low-temperature heat is stored in the heat storage structure through the second branch, thereby improving the load deep adjustment capability of the unit while reducing waste heat loss. When the low-temperature heat source is a boiler, when the boiler exhausts less smoke, the heat in the exhaust is stored in the heat storage structure through the second branch, and the heat in the low-temperature heat source is applied to the heat pump 1 through the heat storage structure. When the boiler exhausts more smoke, the heat in the low-temperature heat source is directly applied to the heat pump 1 through the first branch. Alternatively, a part of the heat in the low-temperature heat source is directly applied to the heat pump 1 through the first branch, and the other part of the low-temperature heat is stored in the heat storage structure through the second branch, thereby reducing waste heat loss while improving the load deep adjustment capability of the unit. The cogeneration system of the present application can recover discontinuous, unstable, low-quality thermal energy generated in the cogeneration, thereby improving the efficiency of the cogeneration system.

[0046] Further, the low-temperature heat source is an intermittent low-temperature heat source, such as a steam turbine or a boiler. Specifically, in this embodiment, the low-temperature heat source is a low-pressure cylinder 9, the heat exchanger is a condenser 8, the heat storage structure includes a cooling tower pool 6-2, and the cogeneration system also includes a medium-pressure cylinder 10 and a heat network heater 12. The medium-pressure cylinder 10 and the low-pressure cylinder 9 can be connected and disconnected, the low-pressure cylinder 9 is connected to the heat exchanger, the medium-pressure cylinder 10 is connected to the heat network heater 12, and the heat pump 1 is connected to the heat network heater 12. Further, the heat storage structure also includes a circulation pipeline connected to the cooling tower pool 6-2, and also includes an additional tower pool or water tank (box).

[0047] Specifically, Figure 1 As shown, when the steam turbine of the present application adopts the low-pressure cylinder 9 zero-output technology or the low-pressure cylinder 9 micro-output technology, when the electrical load is low and the thermal load is high, the sixth valve 11 on the pipeline between the medium-pressure cylinder 10 and the low-pressure cylinder 9 of the steam turbine is closed, and except for a very small amount of exhaust steam from the medium-pressure cylinder 10 entering the low-pressure cylinder 9, the rest is all used to enter the heat network heater 12 for heat exchange with the heating pipeline, and a small amount of exhaust steam in the low-pressure cylinder 9 enters the condenser 8, which can be connected to the condenser 8 and the heat storage structure through the second branch to store low-temperature thermal energy and reduce heat loss. When the temperature in the heat storage structure meets the demand of the heat pump 1, heat can be provided to the heat pump 1 through the heat storage structure. When the electrical load is high or the thermal load is not too high, the sixth valve 11 on the pipeline between the intermediate pressure cylinder 10 and the low pressure cylinder 9 of the steam turbine is opened, and the unit returns to the extraction and condensation operation mode. The exhaust steam of the intermediate pressure cylinder 10 enters the low pressure cylinder 9, and the exhaust steam of the low pressure cylinder 9 enters the condenser 8. The condenser 8 and the heat pump 1 can be connected through the first branch, and the required heat can be directly provided to the heat pump 1 through the condenser 8. While connecting the condenser 8 and the heat pump 1, the condenser 8 and the cooling tower pool 6-2 can be connected through the second branch to store part of the low-temperature heat in the heat storage structure.

[0048] Specifically, Figure 1 As shown, the first branch is provided with a first valve 3, through which the connection between the heat exchanger and the heat pump 1 is controlled. The second branch is provided with a second valve 5, through which the connection between the heat exchanger and the heat storage structure is controlled.

[0049] Specifically, the outlet of the heat exchanger is also connected to the cooling tower water distribution layer 6-1 through the third branch. The third valve 4 is provided on the third branch, and the on-off of the heat exchanger and the cooling tower water distribution layer 6-1 is controlled by the third valve 4. The cooling tower water distribution layer 6-1 can be used to cool the water after heat exchange, so as to control the temperature of the exchanged water within a preset range, which meets the heat storage requirements of the heat storage structure, and can also remove excess heat on the premise of meeting the requirements of the heat pump 1 and the heat storage structure, thereby improving the system safety and system heat exchange efficiency.

[0050] Specifically, the cogeneration system further includes a circulating water pump 7. The outlet of the heat storage structure and the water-side inlet of the heat exchanger are connected through a heat storage branch, and the circulating water pump 7 is arranged on the heat storage branch. The circulating water pump 7 is used to send water in the heat storage structure to the heat exchanger, and recover heat from the low-temperature heat source in the heat exchanger.

[0051] Specifically, the cogeneration system further includes a heating branch, through which the inlet of the heat pump 1 and the outlet of the circulating water pump 7 are connected. The circulating water pump 7 is also used to deliver water in the heat storage structure to the heat pump 1, and deliver heat in the heat storage structure to the heat pump 1.

[0052] As a specific example, Figure 1 As shown, the cogeneration system includes a heat pump 1, a medium pressure cylinder 10, a low pressure cylinder 9, a condenser 8, a cooling tower water distribution layer 6-1, a cooling tower pool 6-2, a circulating water pump 7, and a heat network heater 12. The heat network return water flows into the heat network heater 12 after passing through the heat pump 1, and the water after passing through the heat network heater 12 is used as the heat network supply water to provide heat to users. The heat network heater 12 and the medium pressure cylinder 10 are connected through a pipeline, and the medium pressure cylinder 10 and the low pressure cylinder 9 can be connected through the sixth valve 11, and the exhaust steam of the low pressure cylinder 9 enters the condenser 8. The water side outlet of the condenser 8 can be connected through the first valve 3 and the inlet of the heat pump 1, and the first valve 3 is set on the first branch. The cooling tower pool 6-2 is a heat storage structure and can be connected through the second valve 5 and the water side outlet of the condenser 8, and the second valve 5 is set on the second branch. The cooling tower water distribution layer 6-1 and the water side outlet of the condenser 8 can be connected through the third valve 4, and the third valve 4 is set on the third branch. The outlet of the cooling tower pool 6-2 and the water side inlet of the condenser 8 are connected through a circulating water pump 7, and the circulating water pump 7 is arranged on the heat storage branch. The heating branch connects the inlet of the heat pump 1 and the outlet of the circulating water pump 7, and a fifth valve 13 is arranged on the heating branch, which can be used to control the connection between the heat storage structure and the heat pump 1. The outlet of the heat pump 1 and the cooling tower pool 6-2 are connected through a pipeline, and the fourth valve 2 controls the connection between the outlet of the heat pump 1 and the cooling tower pool 6-2.

[0053] This embodiment further provides an operation method of a cogeneration system, which is applied to the cogeneration system as described above, and the method includes:

[0054] When the low-temperature heat source is in the first operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat pump 1 through the first branch and is used by the heat pump 1 to heat the water in the heating pipeline, or,

[0055] A portion of the water flowing out of the water side outlet of the heat exchanger is controlled to enter the inlet of the heat pump 1 through the first branch, driving the heat pump 1 to heat the water in the heating pipeline, and the other portion of the water flows into the inlet of the heat storage structure through the second branch to store heat in the heat storage structure;

[0056] When the low-temperature heat source is in the second operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat storage structure through the second branch, and heat is stored in the heat storage structure. The water in the heat storage structure enters the inlet of the heat pump 1 from the outlet of the heat storage structure, and the heat stored in the heat storage structure drives the heat pump 1 to heat the water in the heating pipeline, or,

[0057] The water flowing out of the water-side outlet of the control heat exchanger enters the inlet of the heat pump 1 through the first branch, and is used by the heat pump 1 to heat the water in the heating pipeline.

[0058] Specifically, the low-temperature heat source is an intermittent heat source. In the first operating state, the heat energy in the low-temperature heat source is sufficient, and in the second operating state, the heat energy in the low-temperature heat source is less. For example, when the low-temperature heat source is the low-pressure cylinder 9 of the steam turbine, in the first operating state, the electrical load is high or the thermal load is not too high, and the exhaust steam of the intermediate pressure cylinder 10 all enters the low-pressure cylinder 9. In the second operating state, the electrical load is low and the thermal load is high, and a small amount of exhaust steam from the intermediate pressure cylinder 10 enters the low-pressure cylinder 9.

[0059] Specifically, when the first branch and the second branch are connected at the same time, the amount of water entering the heat pump 1 and the amount of water entering the heat storage structure can be set according to actual conditions on site and regulated by the first valve 3 and the second valve 5.

[0060] Specifically, in the first embodiment, a sensor is provided in the cogeneration system, and the heat of the low-temperature heat source can be calculated by the feedback information of the sensor, so as to judge the operating state of the low-temperature heat source. The circulating water volume, inlet and outlet water temperature and other information flowing through the condenser 8 can be obtained by the sensor, and the heat of the low-temperature heat source can be calculated. By comparing the heat of the low-temperature heat source with the heat preset value, it can be judged whether the low-temperature heat source is in the first operating state or the second operating state. For example, if the heat of the low-temperature heat source is higher than the heat preset value, the low-temperature heat source is judged to be in the first operating state, and if the heat of the low-temperature heat source is lower than the heat preset value, the low-temperature heat source is judged to be in the second operating state. The specific numerical value of the heat preset value is not limited here and can be set according to actual needs.

[0061] Specifically, when the low-temperature heat source is the low-pressure cylinder 9 of the steam turbine, when it is judged that the heat absorption of the circulating water in the condenser 8 is less than the preset heat value, the low-temperature heat source is judged to be in the second operating state, and when it is judged that the heat absorption of the circulating water in the condenser 8 is greater than or equal to the preset heat value, the low-temperature heat source is judged to be in the first operating state. When the low-temperature heat source is the exhaust gas of the boiler, when it is judged that the heat absorption of the circulating water in the condenser 8 is less than the preset heat value, the low-temperature heat source is judged to be in the second operating state, and when it is judged that the heat absorption of the circulating water in the condenser 8 is greater than or equal to the preset heat value, the low-temperature heat source is judged to be in the first operating state. The specific value of the preset heat value is not limited here and can be set according to actual needs.

[0062] Specifically, in the second implementation scheme, the steam turbine adopts the low-pressure cylinder 9 zero output technology or the low-pressure cylinder 9 micro-output technology. When the low-temperature heat source is the low-pressure cylinder 9 of the steam turbine, when the sixth valve 11 is closed, the low-temperature heat source is judged to be in the second operating state, and when the sixth valve 11 is opened, the low-temperature heat source is judged to be in the first operating state. The opening and closing state of the sixth valve 11 can be obtained by a sensor.

[0063] Specifically, Figure 1 As shown, this embodiment adopts the second implementation scheme mentioned above, and the control method is simple, intuitive and effective.

[0064] As a specific embodiment, the operation method of the cogeneration system includes:

[0065] When the sixth valve 11 is opened and the low-temperature heat source is in the first operating state, the first valve 3, the fourth valve 2, the circulating water pump 7, and the second valve 5 are controlled to be opened, and the third valve 4 and the fifth valve 13 are controlled to be closed, and a part of the water flowing out of the water side outlet of the heat exchanger (i.e., the condenser 8) enters the inlet of the heat pump 1 through the first branch, and is used by the heat pump 1 to heat the water in the heating pipeline, and the water flowing out of the outlet of the heat pump 1 flows into the heat storage structure (i.e., the cooling tower pool 6-2) through the fourth valve 2, and the other part directly enters the cooling tower pool 6-2 through the second branch, and the water in the cooling tower pool 6-2 enters the heat exchanger (i.e., the condenser 8) again through the circulating water pump 7. At this time, the heat in the exhaust steam is recovered by the heat pump 1 and the heat storage structure (i.e., the cooling tower pool 6-2), and the heat pump 1 can preheat the return water of the heat network to recover a part of the heat in the exhaust steam, and the heat storage structure (i.e., the cooling tower pool 6-2) also recovers a part of the heat in the exhaust steam. When multiple steam turbines, multiple condensers 8, and multiple cooling towers are set up in the system for joint operation, excess heat can be stored by setting up a heat storage tank to increase the heat storage and operation time. It can also avoid storing high-quality heat energy of the intermediate pressure cylinder, reducing the difficulty of storage.

[0066] When the sixth valve 11 is closed and the low-temperature heat source is in the second operating state, the first valve 3 and the third valve 4 are controlled to be closed, and the second valve 5, the fourth valve 2, the fifth valve 13 and the circulating water pump 7 are controlled to be opened. The water in the heat storage structure (i.e., the cooling tower pool 6-2) enters the inlet of the heat pump 1 through the circulating water pump 7 from the outlet of the heat storage structure (i.e., the cooling tower pool 6-2), and enters the heat exchanger (i.e., the condenser 8). The part entering the heat pump 1 completes the heat exchange in the heat pump 1 and re-enters the heat storage structure (i.e., the cooling tower pool 6-2) through the fourth valve 2. The part entering the heat exchanger (i.e., the condenser 8) completes the heat exchange in the heat exchanger and re-enters the heat storage structure through the second valve 5. structure (i.e. cooling tower pool 6-2); or, the third valve 4 and the fifth valve 13 are controlled to be closed, the first valve 3, the fourth valve 2 and the circulating water pump 7 are controlled to be opened, and the second valve 5 is opened or closed according to the specific water volume, and the water in the heat storage structure (i.e. cooling tower pool 6-2) enters the heat exchanger (i.e. condenser 8) from the outlet of the heat storage structure (i.e. cooling tower pool 6-2) through the circulating water pump 7 to complete the heat exchange, and then enters the heat pump 1 through the first valve 3, and after the heat exchange in the heat pump 1, flows into the heat storage structure (i.e. cooling tower pool 6-2) through the fourth valve 2; at this time, if the flow rate of the circulating water pump 7 is higher than the flow rate of the water entering the heat pump, the second valve 5 can be opened appropriately to maintain the stable operation of the system. When multiple steam turbines, multiple condensers 8, and multiple cooling towers are set in the system for joint operation, the low-pressure cylinder exhaust steam of multiple steam turbines can be used to exchange heat in the condenser 8 to increase the heat exchange capacity of the circulating water in the condenser 8.

[0067] Furthermore, the method further comprises:

[0068] The water temperature in the heat storage structure (i.e., cooling tower pool 6-2) is obtained. When the water temperature in the heat storage structure (i.e., cooling tower pool 6-2) is less than or equal to the first preset value, the circulating water pump 7 is controlled to drive the water in the heat storage structure (i.e., cooling tower pool 6-2) to circulate between the heat exchanger (i.e., condenser 8) and the heat storage structure (i.e., cooling tower pool 6-2). The first preset value is the lowest heat storage temperature of the heat storage structure, and can also be the lowest temperature that can be used by the heat pump 1. When the temperature of the water in the heat storage structure is greater than the first preset value, the first valve 3 and the third valve 4 are controlled to be closed, and the second valve 5, the fourth valve 2, the fifth valve 13 and the circulating water pump 7 are controlled to be opened, and the water in the heat storage structure (i.e., the cooling tower pool 6-2) enters the inlet of the heat pump 1 through the circulating water pump 7 from the outlet of the heat storage structure (i.e., the cooling tower pool 6-2), and enters the heat exchanger (i.e., the condenser 8). The part entering the heat pump 1 completes the heat exchange in the heat pump 1 and re-enters the heat storage structure (i.e., the cooling tower pool 6-2) through the fourth valve 2, and the part entering the heat exchanger (i.e., the condenser 8) completes the heat exchange in the heat exchanger and re-enters the heat storage structure (i.e., the cooling tower pool 6-2) through the second valve 5. The specific value of the first preset value is not limited here and can be set according to actual needs.

[0069] The water temperature in the heat storage structure (i.e., cooling tower pool 6-2) is obtained. When the water temperature in the heat storage structure (i.e., cooling tower pool 6-2) is greater than or equal to the second preset value, the circulating water pump 7 is controlled to drive the water in the heat storage structure (i.e., cooling tower pool 6-2) to circulate between the heat exchanger (i.e., condenser 8), heat pump 1, cooling tower water distribution layer 6-1 and heat storage structure (i.e., cooling tower pool 6-2). Specifically, the second preset value is the maximum heat storage temperature of the heat storage structure. When the temperature of the water in the heat storage structure is greater than the second preset value, the first valve 3 and the second valve 5 are controlled to be closed, and the third valve 4, the fourth valve 2, the fifth valve 13 and the circulating water pump 7 are controlled to be opened, and the water in the heat storage structure (i.e., the cooling tower pool 6-2) enters the inlet of the heat pump 1 through the circulating water pump 7 from the outlet of the heat storage structure (i.e., the cooling tower pool 6-2), and enters the heat exchanger (i.e., the condenser 8). The part entering the heat pump 1 completes the heat exchange in the heat pump 1 and re-enters the heat storage structure (i.e., the cooling tower pool 6-2) through the fourth valve 2, and the part entering the heat exchanger (i.e., the condenser 8) completes the heat exchange in the heat exchanger and enters the cooling tower water distribution layer 6-1 through the third valve 4, and falls into the heat storage structure (i.e., the cooling tower pool 6-2) after heat dissipation in the cooling tower. The specific value of the second preset value is not limited here and can be set according to actual needs.

[0070] The method also includes:

[0071] When the heat of the low-temperature heat source is greater than the heat required by the heat pump, and the temperature of the water in the heat storage structure (i.e., the cooling tower pool 6-2) is greater than or equal to the second preset value, the circulating water pump is controlled to drive the water after heat exchange in the heat exchanger to enter the cooling tower water distribution layer from the water side outlet through the third branch. Specifically, the circulating water pump 7 is controlled to drive the water in the heat storage structure (i.e., the cooling tower pool 6-2) to circulate between the heat exchanger (i.e., the condenser 8), the heat pump 1, the cooling tower water distribution layer 6-1 and the heat storage structure (i.e., the cooling tower pool 6-2).

[0072] Specifically, when the heat of the low-temperature heat source is greater than the heat required by the heat pump and the temperature of the water in the heat storage structure is greater than the second preset value, the second valve 5 and the fifth valve 13 are controlled to be closed, and the first valve 3, the third valve 4, the fourth valve 2 and the circulating water pump 7 are controlled to be opened, and the water in the heat storage structure (i.e., the cooling tower pool 6-2) enters the heat exchanger (i.e., the condenser 8) from the outlet of the heat storage structure (i.e., the cooling tower pool 6-2) through the circulating water pump 7, and a part of the circulating water at the outlet of the heat exchanger (i.e., the condenser 8) enters the heat pump 1, and the other part enters the cooling tower water distribution layer 6-1 through the third valve 4. After completing the heat exchange in the heat pump 1, the water entering the heat pump re-enters the heat storage structure (i.e., the cooling tower pool 6-2) through the fourth valve 2, and the part entering the cooling tower water distribution layer 6-1 falls into the heat storage structure (i.e., the cooling tower pool 6-2) after heat dissipation in the cooling tower. The specific value of the second preset value is not limited here and can be set according to actual needs.

[0073] In this embodiment, a heat and power cogeneration system is provided, in which a steam turbine, a condenser 8, and a cooling tower are provided. Alternatively, multiple steam turbines, multiple condensers 8, and multiple cooling towers may be provided for joint operation to increase heat storage and operation time. Alternatively, multiple boiler exhausts may be jointly operated to increase heat storage and operation time.

[0074] The cogeneration system of this embodiment can recover discontinuous, unstable, and low-quality thermal energy generated in the cogeneration process, thereby improving the efficiency of the cogeneration system.

[0075] In the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0076] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cogeneration system, characterized in that: include: Low temperature heat source, heat pump, heat exchanger, heat storage structure; The heat pump is arranged on the heating pipeline, the low-temperature heat source is connected to the heat exchanger, the water side outlet of the heat exchanger is connected to the inlet of the heat pump through the first branch, and the outlet of the heat pump is connected to the inlet of the heat storage structure; The water side outlet of the heat exchanger is also connected to the inlet of the heat storage structure through a second branch, and the outlet of the heat storage structure is connected to the water side inlet of the heat exchanger or / and the inlet of the heat pump.

2. A cogeneration system according to claim 1, characterized in that: The low-temperature heat source includes a steam turbine and / or a boiler.

3. A cogeneration system according to claim 1, characterized in that: The low temperature heat source includes a low pressure cylinder; The heat exchanger is a condenser; The cogeneration system also includes a medium-pressure cylinder and a heat network heater. The medium-pressure cylinder and the low-pressure cylinder are connected in an on-off manner. The low-pressure cylinder is connected to the heat exchanger. The medium-pressure cylinder is connected to the heat network heater. The heat pump is connected to the heat network heater.

4. A cogeneration system according to claim 1, characterized in that: The heat storage structure includes a cooling tower pool.

5. A cogeneration system according to claim 1, characterized in that: The outlet of the heat exchanger is also connected to the water distribution layer of the cooling tower through a third branch.

6. A cogeneration system according to claim 1, characterized in that: The cogeneration system also includes a circulating water pump; The outlet of the heat storage structure and the water-side inlet of the heat exchanger are connected via a heat storage branch, and the circulating water pump is arranged on the heat storage branch.

7. A cogeneration system according to claim 6, characterized in that: The cogeneration system also includes a heating branch; The inlet of the heat pump and the outlet of the circulating water pump are connected through the heating branch.

8. A method for operating a cogeneration system, characterized in that: Applied in a cogeneration system as claimed in any one of claims 1 to 7, the method comprises: When the low-temperature heat source is in the first operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat pump through the first branch, and is used by the heat pump to heat the water in the heating pipeline, or, Controlling a portion of the water flowing out of the water-side outlet of the heat exchanger to enter the inlet of the heat pump through the first branch and be used by the heat pump to heat the water in the heating pipeline, and controlling the other portion of the water flowing out of the water-side outlet of the heat exchanger to enter the heat storage structure through the second branch and store heat in the heat storage structure; When the low-temperature heat source is in the second operating state, the water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat storage structure through the second branch, and heat is stored in the heat storage structure. The water in the heat storage structure enters the inlet of the heat pump and / or the water-side inlet of the heat exchanger from the outlet of the heat storage structure, and the heat stored in the heat storage structure is used by the heat pump to heat the water in the heating pipeline, or, The water flowing out of the water-side outlet of the heat exchanger is controlled to enter the inlet of the heat pump through the first branch, and is used by the heat pump to heat the water in the heating pipeline.

9. The method for operating a cogeneration system according to claim 8, characterized in that: The method further comprises: When the temperature of the water in the heat storage structure is less than or equal to a first preset value, controlling a circulating water pump to drive the water in the heat storage structure to circulate between the heat exchanger and the heat storage structure; When the temperature of the water in the heat storage structure is greater than or equal to a second preset value, the circulating water pump is controlled to drive the water in the heat storage structure to circulate between the heat exchanger, the cooling tower water distribution layer and the heat storage structure.

10. The method for operating a cogeneration system according to claim 9, characterized in that: The method further comprises: When the heat of the low-temperature heat source is greater than the heat required by the heat pump and the temperature of the water in the heat storage structure is greater than or equal to a second preset value, the circulating water pump is controlled to drive the water after heat exchange in the heat exchanger to enter the cooling tower water distribution layer from the water side outlet through the third branch.

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