Steam production system and control method thereof

Abstract

This application provides a steam production system and its control method. The system includes a low-temperature heat storage tank, a high-temperature heat storage tank, a first component having a first flash evaporation unit, a second flash evaporation unit, and an electric heat pump unit. The water inlet and water outlet of the first flash evaporation unit are respectively connected to the water inlet and water outlet of the first component, and the water inlet of the first component is used to connect to the heat source water supply pipeline; the first interface of the low-temperature heat storage tank is connected to the water outlet of the first component and the evaporator inlet of the electric heat pump unit, and the second interface of the low-temperature heat storage tank is connected to the evaporator outlet of the electric heat pump unit and is used to connect to the heat source return water pipeline; the first interface of the high-temperature heat storage tank is connected to the condenser outlet of the electric heat pump unit and the water inlet of the second flash evaporation unit, and the second interface of the high-temperature heat storage tank is connected to the condenser inlet of the electric heat pump unit and the water outlet of the second flash evaporation unit; the steam outlet of the first flash evaporation unit and the steam outlet of the second flash evaporation unit are both used to connect to the steam transmission pipeline.

Description

Technical Field

[0001] This application relates to the field of industrial heat technology, and in particular to a steam production system and its control method. Background Technology

[0002] Industrial heat consumption mainly includes processes such as heating, distillation, drying, and sterilization, accounting for over 60% of energy consumption in most industrial sectors. Currently, industrial heat primarily comes from decentralized coal / gas-fired boilers and centralized steam transportation from combined heat and power (CHP) plants. Decentralized boiler heating typically employs a high-pressure production and end-point throttling model, resulting in significant waste of high-grade energy. Centralized CHP steam transportation, on the other hand, faces challenges because power plants are often located far from users. During long-distance transport, the temperature and pressure of the steam undergo significant changes due to pipeline heat dissipation and friction resistance, limiting the development and application of long-distance steam transportation systems. Therefore, a water-steam conversion technology has been proposed to supply high-grade steam at the user's location by recovering low-temperature waste heat from the plant or supplying heat via long-distance hot water transportation, and then utilizing flash evaporation or post-flash compression. While this technology solves the problems of grade mismatch and transportation difficulties, its high power consumption and cost have prevented its widespread application in the industrial heating sector.

[0003] In recent years, the installed capacity of renewable energy has gradually increased. However, the intermittent, fluctuating, and random nature of renewable energy power generation leads to surplus wind and solar power, resulting in severe "wind curtailment" and "solar curtailment," which also significantly impacts the regulation of the power grid system. Therefore, it is crucial to improve the utilization efficiency of heat source water, increase steam production, and implement peak shaving and valley filling technologies to absorb electricity during periods of low electricity prices and reduce electricity consumption during periods of high electricity prices. Summary of the Invention

[0004] The purpose of this application is to provide a steam production system and its control method, which can improve the economic efficiency of the steam production system and enhance its peak shaving and valley filling regulation capabilities.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] Technical Solution 1: A steam production system, comprising a low-temperature heat storage tank, a high-temperature heat storage tank, a first component having a first flash evaporation unit, a second flash evaporation unit, and an electric heat pump unit, wherein the first component has a water inlet and a water outlet, wherein...

[0007] The water inlet and water outlet of the first flash evaporation unit are connected to the water inlet and water outlet of the first component, respectively. The water inlet of the first component is used to connect to the heat source water supply pipeline.

[0008] The first interface of the low-temperature heat storage tank is connected to the water outlet of the first component and the evaporator inlet of the electric heat pump unit, and the second interface of the low-temperature heat storage tank is connected to the evaporator outlet of the electric heat pump unit and is used to connect to the heat source return water pipeline.

[0009] The first interface of the high-temperature heat storage tank is connected to the condenser outlet of the electric heat pump unit and the water inlet of the second flash evaporation unit, and the second interface of the high-temperature heat storage tank is connected to the condenser inlet of the electric heat pump unit and the water outlet of the second flash evaporation unit.

[0010] The steam outlets of the first flash unit and the second flash unit are both used to connect to the steam delivery pipeline.

[0011] Technical Solution 2: The steam production system as described in Technical Solution 1, wherein the first component further includes a heat exchange unit, and the water inlet and water outlet of the first flash evaporation unit are respectively connected to the water inlet and water outlet of the first component through the heat exchange unit, wherein...

[0012] The first and second interfaces of the heat exchange unit are connected to the water inlet and water outlet of the first component, respectively, and the third and fourth interfaces of the heat exchange unit are connected to the water inlet and water outlet of the first flash evaporation unit, respectively.

[0013] Technical Solution 3: The steam production system as described in Technical Solution 1 further includes a compressor unit, wherein,

[0014] The steam inlet of the compressor unit is connected to the steam outlet of either the first flash unit or the second flash unit, and the steam outlet of the compressor unit is used to connect to the steam delivery pipeline.

[0015] Technical Solution 4: The steam production system as described in Technical Solution 3, wherein any one of the first flash unit and the second flash unit includes a multi-stage flash evaporator, the multi-stage flash evaporators are connected in series, wherein the water inlet of the first stage flash evaporator and the water outlet of the last stage flash evaporator serve as the water inlet and water outlet of the flash unit, respectively, and the water outlet and water inlet of adjacent flash evaporators are connected.

[0016] The compressor unit includes a multi-stage compressor connected in series. The steam outlet of each stage of the flash evaporator is connected to the steam inlet of the corresponding stage of the compressor. The steam outlets and steam inlets of adjacent stages of the compressor are connected.

[0017] Technical Solution 5: The steam production system as described in Technical Solution 1, wherein the electric heat pump unit includes a multi-stage electric heat pump, and the multi-stage electric heat pumps are connected in series, wherein,

[0018] The first and second interfaces of the low-temperature heat storage tank are respectively connected to the evaporator inlet of the first-stage electric heat pump and the evaporator outlet of the last-stage electric heat pump, and the evaporator inlet and evaporator outlet of the electric heat pumps of adjacent stages are connected.

[0019] The first and second interfaces of the high-temperature heat storage tank are respectively connected to the condenser outlet of the first-stage electric heat pump and the condenser inlet of the last-stage electric heat pump, and the condenser inlets and outlets of adjacent electric heat pumps are connected.

[0020] Technical Solution 6: The steam production system as described in any one of Technical Solutions 1 to 5, wherein a first valve is provided in the connecting pipe at the evaporator outlet of the electric heat pump unit; a second valve is provided in the connecting pipe at the condenser inlet of the electric heat pump unit; and a third valve is provided in the pipe at at least one of the first and second interfaces of the high-temperature heat storage tank.

[0021] Technical Solution 7: The steam production system as described in Technical Solution 6, wherein the steam production system has at least one of a first operating mode, a second operating mode, and a third operating mode, wherein,

[0022] In the first operating mode, the first valve and the second valve are closed, the third valve is open, the electric heat pump unit stops operating, and both the low-temperature heat storage tank and the high-temperature heat storage tank are disconnected from the electric heat pump unit;

[0023] In the second operating mode, the first valve, the second valve, and the third valve are all open, and the electric heat pump unit operates normally. The low-temperature heat storage tank releases heat, and the high-temperature heat storage tank stores heat.

[0024] In the third operating mode, the first valve and the second valve are open, the third valve is closed, and the electric heat pump unit is partially operational. In this mode, the low-temperature heat storage tank does not release heat, and the high-temperature heat storage tank does not store heat.

[0025] Technical Solution 8: The steam production system as described in Technical Solution 7 operates in the first mode during peak electricity price periods; in the second mode during off-peak electricity price periods; and in the third mode during off-peak electricity price periods.

[0026] Technical Solution 9: A control method for a steam production system, the steam production system comprising a low-temperature thermal storage tank, a high-temperature thermal storage tank, a first component having a first flash evaporation unit, a second flash evaporation unit, and an electric heat pump unit, the control method comprising:

[0027] During peak electricity price periods, the steam production system is controlled to operate in a first operating mode. In the first operating mode, the electric heat pump unit is stopped, and both the low-temperature heat storage tank and the high-temperature heat storage tank are disconnected from the electric heat pump unit. The steam after flashing through the first flash unit and the high-temperature water stored in the high-temperature heat storage tank after flashing through the second flash unit enter the steam delivery pipeline together.

[0028] During off-peak electricity price periods, the steam production system is controlled to operate in a second mode. In this second mode, the electric heat pump unit is controlled to operate normally. Both the low-temperature heat storage tank and the high-temperature heat storage tank are connected to the electric heat pump unit. The low-temperature water cooled by the first component mixes with the effluent from the low-temperature heat storage tank and enters the electric heat pump unit. A portion of the hot water heated by the electric heat pump unit enters the second flash evaporation unit, while the other portion is stored in the high-temperature heat storage tank. The steam after flash evaporation by the second flash evaporation unit and the steam after flash evaporation by the first flash evaporation unit both enter the steam delivery pipeline.

[0029] Technical solution 10: The control method as described in technical solution 9, the control method further comprising:

[0030] During the flat electricity price period, the steam production system is controlled to operate in a third mode. In this third mode, the electric heat pump unit is partially operated, and the electric heat pump unit is disconnected from the high-temperature heat storage tank. Low-temperature water cooled by the first component enters the electric heat pump unit, and hot water heated by the electric heat pump unit enters the second flash evaporation unit. The steam after flash evaporation in the second flash evaporation unit and the steam after flash evaporation in the first flash evaporation unit enter the steam delivery pipeline together. The low-temperature heat storage tank does not release heat, and the high-temperature heat storage tank does not store heat.

[0031] Technical Solution 11: The control method as described in Technical Solution 9 or 10, wherein the steam production system further includes a compressor unit, and the control method further includes:

[0032] The steam generated by flash evaporation in either the first flash unit or the second flash unit is further compressed by the compressor unit and then enters the steam delivery pipeline.

[0033] Technical Solution 12: The control method as described in Technical Solution 9 or 10, wherein the first component further comprises a heat exchange unit, and the control method further comprises:

[0034] Before the hot water passes through the first flash evaporation unit in the first component, it is introduced into the heat exchange unit in the first component to exchange heat with the flash return water after flash evaporation in the first flash evaporation unit. The hot water heated by the heat exchange unit then enters the first flash evaporation unit for flash evaporation.

[0035] The low-temperature water cooled by the first component includes: low-temperature water cooled by heat exchange in the heat exchange unit.

[0036] The steam production system and its control method provided by one or more technical solutions in this application achieve cascade utilization of heat source water in different ways according to different grades, thereby making full use of heat and improving overall efficiency.

[0037] The steam production system and its control method provided by one or more technical solutions in this application utilize a high-temperature thermal storage tank, a low-temperature thermal storage tank, and an electric heat pump unit to transfer electricity from periods with low electricity prices to periods with high electricity prices, thereby contributing to the consumption of renewable energy and the regulation of the power grid.

[0038] The steam production system and its control method provided by one or more technical solutions in this application improve the economic efficiency of the steam production system by adjusting the operating strategy for different time periods and changing the equipment operation mode during different electricity price periods, using more electricity during low electricity price periods and reducing electricity consumption during high electricity price periods. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the steam production system according to the first embodiment of this application.

[0040] Figure 2 This is a schematic diagram of the steam production system according to the second embodiment of this application.

[0041] Figure 3 This is a schematic diagram of the steam production system according to the third embodiment of this application.

[0042] Figure 4 This is a schematic diagram of the steam production system according to the fourth embodiment of this application.

[0043] Figure 5 This is a schematic diagram of the steam production system according to the fifth embodiment of this application.

[0044] Figure 6 This is a schematic diagram of the steam production system according to the sixth embodiment of this application.

[0045] Figure 7 This is a schematic diagram of the steam production system of this application in the first operating mode.

[0046] Figure 8This is a schematic diagram of the steam production system of this application in the second operating mode.

[0047] Figure 9 This is a schematic diagram of the steam production system of this application in the third operating mode. Detailed Implementation

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0049] This application proposes a steam production system and its control method, which optimizes the system process for producing industrial steam from hot water and proposes corresponding operating modes for different electricity consumption periods. The hot water transportation technology is mature and highly reliable, and the water-to-steam technology is environmentally friendly and significantly improves thermal efficiency. Furthermore, while retaining the advantages of water-to-steam technology, this application reduces the system's heating costs, enhances the absorption capacity of renewable energy, and mitigates the "curtailment" phenomenon caused by the volatility and intermittency of renewable energy, thereby broadening the application prospects of water-to-steam technology.

[0050] The steam production system and its control method according to various embodiments of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementation methods can be combined with each other.

[0051] First Embodiment

[0052] Figure 1 A schematic diagram of the steam production system according to the first embodiment of this application is shown. Figure 1 As shown, the steam production system includes a low-temperature heat storage tank 1, a first component 2, a second flash evaporation unit 3, an electric heat pump unit 4, and a high-temperature heat storage tank 5.

[0053] The first component 2 has a water inlet 201 and a water outlet 202. The first component 2 includes a first flash evaporation unit 21. The water inlet and water outlet of the first flash evaporation unit 21 are connected to the water inlet 201 and the water outlet 202 of the first component 2, respectively. The water inlet 201 of the first component 2 is used to connect to the heat source water supply pipeline 71.

[0054] The low-temperature heat storage tank 1 has a first interface 11 and a second interface 12. The first interface 11 of the low-temperature heat storage tank 1 is connected to the water outlet 202 of the first component 2 and the evaporator inlet of the electric heat pump unit 4. The second interface 12 of the low-temperature heat storage tank 1 is connected to the evaporator outlet of the electric heat pump unit 4 and is used to connect to the heat source return water pipeline 72.

[0055] The high-temperature heat storage tank 5 has a first interface 51 and a second interface 52. The first interface 51 of the high-temperature heat storage tank 5 is connected to the condenser outlet of the electric heat pump unit 4 and the water inlet of the second flash evaporation unit 3, and the second interface 52 of the high-temperature heat storage tank 5 is connected to the condenser inlet of the electric heat pump unit 4 and the water outlet of the second flash evaporation unit 3.

[0056] The steam outlets of the first flash evaporation unit 21 and the second flash evaporation unit 3 are both connected to the steam delivery pipeline 73 to supply steam to the user.

[0057] Second Embodiment

[0058] Figure 2 A schematic diagram of the steam production system according to the second embodiment of this application is shown. Figure 2 As shown, Figure 2 The steam production system shown is Figure 1 The difference in the steam production system shown is that, Figure 2 In the steam production system shown, the first component 2 also includes a heat exchange unit 22. The water inlet and water outlet of the first flash evaporation unit 21 are connected to the water inlet 201 and water outlet 202 of the first component 2 respectively through the heat exchange unit 22.

[0059] The heat exchange unit 22 has a first interface 221, a second interface 222, a third interface 223, and a fourth interface 224. The first interface 221 and the second interface 222 of the heat exchange unit 22 are respectively connected to the water inlet 201 and the water outlet 202 of the first component 2, and the third interface 223 and the fourth interface 224 of the heat exchange unit 22 are respectively connected to the water inlet and the water outlet of the first flash evaporation unit 21.

[0060] Third Embodiment

[0061] Figure 3 A schematic diagram of the steam production system according to the third embodiment of this application is shown. Figure 3 As shown, Figure 3 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 3 The steam production system shown may also include a compressor unit 6. The steam inlet of the compressor unit 6 is connected to the steam outlet of the first flash evaporation unit 21, and the steam outlet of the compressor unit 6 is used to connect to the steam delivery pipeline 73.

[0062] When the steam parameters produced by the first flash unit 21 are low, the steam produced by the first flash unit 21 can be further compressed by the compressor unit 6 before being delivered to the steam delivery pipeline 73.

[0063] Fourth embodiment

[0064] Figure 4 A schematic diagram of the steam production system according to the fourth embodiment of this application is shown. Figure 4 As shown, Figure 4 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 4 The steam production system shown may also include a compressor unit 6. The steam inlet of the compressor unit 6 is connected to the steam outlet of the second flash evaporation unit 3, and the steam outlet of the compressor unit 6 is used to connect to the steam delivery pipeline 73.

[0065] When the steam parameters produced by the second flash unit 3 are low, the steam produced by the second flash unit 3 can be further compressed by the compressor unit 6 before being delivered to the steam delivery pipeline 73.

[0066] In conjunction with the fourth and fifth embodiments, the steam inlet of the compressor unit 6 of this application can be connected to the steam outlet of any one of the first flash evaporation unit 21 and the second flash evaporation unit 3, depending on the actual application. The steam outlet of the compressor unit 6 is used to connect to the steam delivery pipeline 73.

[0067] Fifth embodiment

[0068] Figure 5 A schematic diagram of the steam production system according to the fifth embodiment of this application is shown. Figure 5 As shown, Figure 5 The steam production system shown is Figure 4 The difference in the steam production system shown is that, Figure 5 In the steam production system shown, the second flash unit 3 has multiple flash stages and the compressor unit 6 has multiple compression stages.

[0069] Specifically, the second flash evaporation unit 3 includes multiple stages of second flash evaporators 30 connected in series, through which flash water passes sequentially. The water inlet of the first stage of the second flash evaporator 30 and the water outlet of the last stage of the second flash evaporator 30 serve as the water inlet and outlet of the second flash evaporation unit 3, respectively, and the water outlets and inlets of adjacent stages of the second flash evaporator 30 are connected.

[0070] The compressor unit 6 includes a multi-stage compressor 60 connected in series, with the steam outlet and steam inlet of adjacent compressor stages 60 connected together. Specifically, the steam outlet of each stage's second flash evaporator 30 is connected to the steam inlet of the corresponding stage compressor 60.

[0071] Optionally, the multi-stage compressor 60 can be designed with an interstage water spraying system, connecting the water outlet of the second flash evaporator 30 of each stage to the steam outlet of the corresponding first-stage compressor 60. This allows the flash return water from the second flash evaporator 30 to reduce the overheating at the outlet of the compressor 60, preventing problems such as carbonization of the compressor 60 lubricating oil and reduction of material stress.

[0072] Alternatively, the first flash unit 21 of this application may also have a multi-stage flash process.

[0073] Therefore, either the first flash unit 21 or the second flash unit 3 of this application can include a multi-stage flash evaporator, which is connected in series. The water inlet of the first-stage flash evaporator and the water outlet of the last-stage flash evaporator serve as the water inlet and outlet of the flash unit, respectively. The water outlets and inlets of adjacent flash evaporators are connected together. The steam outlet of each flash evaporator is connected to the steam inlet of the corresponding first-stage compressor 6060.

[0074] Sixth Embodiment

[0075] Figure 6 A schematic diagram of the steam production system according to the sixth embodiment of this application is shown. Figure 6 As shown, Figure 6 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 6 In the steam production system shown, a first valve 81 is provided in the connecting pipe at the evaporator outlet of the electric heat pump unit 4; a second valve 82 is provided in the connecting pipe at the condenser inlet of the electric heat pump unit 4; and a third valve 83 is provided in the pipe at at least one of the first interface 51 and the second interface 52 of the high-temperature heat storage tank 5.

[0076] Of course, it is understood that the arrangement, number and location of valves in the steam production system of this application are not limited to those shown in the figures of this application. Valves can also be installed in other connecting pipelines in the steam production system of this application. All valves added to the system that serve a shut-off function will be covered by the protection scope of this application.

[0077] In the above embodiments, the electric heat pump unit 4 in the steam production system of this application can be designed as a multi-stage unit. The electric heat pump unit 4 may include multiple stages of electric heat pumps (not shown), which are connected in series. Specifically, the first interface 11 and the second interface 12 of the low-temperature heat storage tank 1 are connected to the evaporator inlet of the first-stage electric heat pump and the evaporator outlet of the last-stage electric heat pump, respectively, and the evaporator inlets and outlets of adjacent stages of the electric heat pump are connected. The first interface 51 and the second interface 52 of the high-temperature heat storage tank 5 are connected to the condenser outlet of the first-stage electric heat pump and the condenser inlet of the last-stage electric heat pump, respectively, and the condenser inlets and outlets of adjacent stages of the electric heat pump are connected.

[0078] Similarly, in other embodiments of this application, the heat exchange unit 22 may also include multiple stages.

[0079] Furthermore, it is understood that the above descriptions are merely some illustrative embodiments of the steam production system of this application. However, the embodiments of the steam production system of this application are not limited thereto, and the solutions shown in the various embodiments of the steam production system of this application can be combined with each other according to actual circumstances. Any combination or simple and equivalent transformations of the above embodiments without departing from the inventive spirit of this application will be within the protection scope of this application.

[0080] In some embodiments, the steam production system of this application may have at least one of a first operating mode, a second operating mode, and a third operating mode.

[0081] The operation mode of the steam production system of this application will be described in detail below using the scheme illustrated in the sixth embodiment.

[0082] During peak electricity price periods, the steam production system of this application can operate in the first mode, thus reducing electricity consumption. Figure 7 A schematic diagram of the steam production system of this application in its first operating mode is shown. (See attached diagram.) Figure 7 As shown, in the first operating mode of the steam production system of this application, the first valve 81 and the second valve 82 are closed, the third valve 83 is open, the electric heat pump unit 4 stops operating, and both the low-temperature heat storage tank 1 and the high-temperature heat storage tank 5 are disconnected from the electric heat pump unit 4.

[0083] The heat source water enters the heat exchange unit 22 directly through the heat source supply water pipeline 71. After heat exchange and cooling, the heat source water enters the low-temperature heat storage tank 1 through the first interface 11, and the low-temperature water in the tank exits through the second interface 12 to the heat source return water pipeline 72. At the same time, the flash return water from the first flash evaporation unit 21 heated by the heat exchange unit 22 and the hot water stored in the high-temperature heat storage tank 5 are used to generate the required steam through flash evaporation and enter the steam transmission pipeline 73.

[0084] During off-peak electricity pricing periods, the steam production system of this application can operate in a second mode, which allows the steam production system of this application to consume more electricity. Figure 8 A schematic diagram of the steam production system of this application in its second operating mode is shown. (See attached diagram.) Figure 8 As shown, in the second operating mode of the steam production system of this application, the first valve 81, the second valve 82 and the third valve 83 are all open, the electric heat pump unit 4 is operating normally, wherein the low temperature heat storage tank 1 releases heat and the high temperature heat storage tank 5 stores heat.

[0085] Heat source water enters heat exchange unit 22 directly through heat source supply pipeline 71. After heat exchange and cooling, the heat source water mixes with the outlet water from the first port 11 of low-temperature storage tank 1 and enters the evaporator in electric heat pump unit 4. The water at the outlet of the evaporator of electric heat pump unit 4 is divided into two streams: one stream enters low-temperature storage tank 1 through the second port 12, and the other stream enters heat source return water pipeline 72. Heat exchange unit 22 and electric heat pump unit 4 heat the flash return water from the first flash evaporation unit 21 and the flash return water from the second flash evaporation unit 3, respectively, and generate the required steam through flash evaporation, which enters steam transmission pipeline 73. At the same time, electric heat pump unit 4 also heats the stored water in high-temperature storage tank 5 through the first port 51 and the second port 52.

[0086] During periods of flat electricity pricing, the steam production system of this application can operate in the third mode. Figure 9 A schematic diagram of the steam production system of this application in the third operating mode is shown. (See attached diagram.) Figure 9 As shown, in the third operating mode of the steam production system of this application, the first valve 81 and the second valve 82 are open, the third valve 83 is closed, and the electric heat pump unit 4 is partially operating. In this mode, the low-temperature heat storage tank 1 does not release heat, and the high-temperature heat storage tank 5 does not store heat.

[0087] The heat source water enters the heat exchange unit 22 directly through the heat source supply water pipeline 71. After heat exchange and cooling, the heat source water connects to the evaporator outlet of the electric heat pump unit 4 via the second interface 12 of the low-temperature heat storage tank 1. The water flow direction at the first interface 11 of the low-temperature heat storage tank 1 is related to the specific design of the scheme, and the water flow direction at the second interface 12 of the low-temperature heat storage tank 1 also corresponds to it. In addition, the water at the evaporator outlet of the electric heat pump unit 4 directly enters the heat source return water pipeline 72. The heat exchange unit 22 and the electric heat pump unit 4 heat the flash return water of the first flash evaporation unit 21 and the flash return water of the second flash evaporation unit 3, respectively, and generate the required steam through flash evaporation, which then enters the steam transmission pipeline 73.

[0088] The steam production system of this application realizes the tiered and comprehensive utilization of hot water of different grades, while also absorbing excess electricity during low-electricity-price periods and reducing electricity consumption during high-electricity-price and flat-electricity-price periods. The tiered and comprehensive utilization of hot water of different grades involves directly flash-producing steam from high-grade hot water, while low-grade hot water is upgraded by an electric heat pump before being used for steam production and heat storage. Furthermore, different operating strategies are employed during different electricity-price periods to achieve peak shaving and valley filling: during high-electricity-price periods, high-grade hot water is flash-cooled and then stored in low-temperature heat storage tank 1, while high-temperature heat storage tank 5 directly flash-produces steam; during low-electricity-price periods, high-grade hot water, after flash-cooling, enters the evaporator in the electric heat pump unit 4 along with the water stored in low-temperature heat storage tank 1, recovering its heat to heat the water stored in high-temperature heat storage tank 5 and to produce steam.

[0089] The steam production system of this application not only realizes peak shaving and valley filling functions and assists in power system regulation, but also further reduces operating costs, improves economic efficiency, and broadens the application scenarios of water-to-steam production.

[0090] This application also provides a control method for a steam production system. The steam production system includes a low-temperature heat storage tank 1, a first component 2 having a first flash evaporation unit 21, a second flash evaporation unit 3, an electric heat pump unit 4, and a high-temperature heat storage tank 5. The control method for the steam production system of this application may include steps S1 to S2.

[0091] In step S1, in conjunction with reference Figure 7 As shown, during peak electricity price periods, the steam production system can be controlled to operate in the first mode. In the first mode, the electric heat pump unit 4 is stopped, and both the low-temperature heat storage tank 1 and the high-temperature heat storage tank 5 are disconnected from the electric heat pump unit 4. The steam after flashing through the first flash unit 21 and the high-temperature water stored in the high-temperature heat storage tank 5, after flashing through the second flash unit 3, enter the steam delivery pipeline 73 together.

[0092] In step S2, in conjunction with reference Figure 8 As shown, during off-peak electricity price periods, the steam production system can be controlled to operate in a second mode. In the second mode, the electric heat pump unit 4 is controlled to operate normally. The low-temperature heat storage tank 1 and the high-temperature heat storage tank 5 are both connected to the electric heat pump unit 4. The low-temperature water cooled by the first component 2 mixes with the outlet water of the low-temperature heat storage tank 1 and enters the electric heat pump unit 4. A portion of the hot water heated by the electric heat pump unit 4 enters the second flash evaporation unit 3, and the other portion of hot water is stored in the high-temperature heat storage tank 5. The steam after flash evaporation by the second flash evaporation unit 3 and the steam after flash evaporation by the first flash evaporation unit 21 enter the steam delivery pipeline 73 together.

[0093] In some embodiments, the control method of the steam production system of this application may further include step S3.

[0094] In step S3, in conjunction with reference Figure 9 As shown, during the flat electricity price period, the steam production system can be controlled to operate in the third mode. In the third mode, the electric heat pump unit 4 is partially operated. The electric heat pump unit 4 is disconnected from the high-temperature heat storage tank 5. The low-temperature water cooled by the first component 2 enters the electric heat pump unit 4. The hot water heated by the electric heat pump unit 4 enters the second flash unit 3. The steam after flashing in the second flash unit 3 and the steam after flashing in the first flash unit 21 enter the steam delivery pipeline 73 together. The low-temperature heat storage tank 1 does not release heat, and the high-temperature heat storage tank 5 does not store heat.

[0095] The steam production system may also include a compressor unit 6. In some embodiments, the control method of the steam production system of this application may further include step S4.

[0096] In step S4, the steam generated by flashing in either the first flash unit 21 or the second flash unit 3 can be further compressed by the compressor unit 6 and then enter the steam delivery pipeline 73.

[0097] The first component 2 may also have a heat exchange unit 22. Therefore, in some embodiments, the control method of the steam production system of this application may further include step S5.

[0098] In step S5, before the hot water is flashed through the first flash unit 21 in the first component 2, the hot water is input into the heat exchange unit 22 in the first component 2 to exchange heat with the flash return water after flashing in the first flash unit 21. The hot water heated by the heat exchange unit 22 then enters the first flash unit 21 for flashing.

[0099] The low-temperature water cooled by the first component 2 includes: low-temperature water cooled by heat exchange unit 22.

[0100] When the first component 2 has a heat exchange unit 22, the low-temperature water cooled by the first component 2 includes: low-temperature water cooled by heat exchange unit 22.

[0101] In the absence of a heat exchange unit 22 in the first component 2, the low-temperature water cooled by the first component 2 includes: flash return water after flashing by the first flash unit 21.

[0102] The control method of the steam production system in one or more embodiments of this application adopts different methods to achieve tiered utilization of heat source water with different grades, thereby making full use of heat and improving overall efficiency.

[0103] The control method of the steam production system in one or more embodiments of this application utilizes a high-temperature thermal storage tank 5, a low-temperature thermal storage tank 1, and an electric heat pump unit 4 to transfer electricity from periods with low electricity prices to periods with high electricity prices, thereby contributing to the consumption of renewable energy and the regulation of the power grid.

[0104] The control method for a steam production system according to one or more embodiments of this application improves the economy of the steam production system by adjusting the operating strategy for different time periods and changing the equipment operation mode during different electricity price periods, using more electricity during low electricity price periods and reducing electricity consumption during high electricity price periods.

[0105] The steam production system and its control method provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the steam production system and its control method in the embodiments of this application. The descriptions of the embodiments above are only for helping to understand the core ideas of this application and are not intended to limit this application. It should be noted that for those skilled in the art, several improvements and modifications can be made to this application without departing from the spirit and principles of this application, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A steam production system, characterized in that: It includes a low-temperature thermal storage tank, a high-temperature thermal storage tank, a first component with a first flash evaporation unit, a second flash evaporation unit, and an electric heat pump unit. The first component has a water inlet and a water outlet. The water inlet and water outlet of the first flash evaporation unit are connected to the water inlet and water outlet of the first component, respectively. The water inlet of the first component is used to connect to the heat source water supply pipeline. The first interface of the low-temperature heat storage tank is connected to the water outlet of the first component and the evaporator inlet of the electric heat pump unit, and the second interface of the low-temperature heat storage tank is connected to the evaporator outlet of the electric heat pump unit and is used to connect to the heat source return water pipeline. The first interface of the high-temperature heat storage tank is connected to the condenser outlet of the electric heat pump unit and the water inlet of the second flash evaporation unit, and the second interface of the high-temperature heat storage tank is connected to the condenser inlet of the electric heat pump unit and the water outlet of the second flash evaporation unit. The steam outlets of the first flash unit and the second flash unit are both used to connect to the steam delivery pipeline.

2. The steam production system as described in claim 1, characterized in that: The first component further includes a heat exchange unit, wherein the water inlet and water outlet of the first flash evaporation unit are respectively connected to the water inlet and water outlet of the first component through the heat exchange unit. The first and second interfaces of the heat exchange unit are connected to the water inlet and water outlet of the first component, respectively, and the third and fourth interfaces of the heat exchange unit are connected to the water inlet and water outlet of the first flash evaporation unit, respectively.

3. The steam production system as described in claim 1, characterized in that: It also includes a compressor unit, wherein, The steam inlet of the compressor unit is connected to the steam outlet of either the first flash unit or the second flash unit, and the steam outlet of the compressor unit is used to connect to the steam delivery pipeline.

4. The steam production system as described in claim 3, characterized in that: The first flash unit and the second flash unit include multiple flash evaporators connected in series. The water inlet of the first flash evaporator and the water outlet of the last flash evaporator serve as the water inlet and water outlet of the flash unit, respectively. The water outlet and water inlet of two adjacent flash evaporators are connected. The compressor unit includes a multi-stage compressor connected in series. The steam outlet of each stage of the flash evaporator is connected to the steam inlet of the corresponding stage of the compressor. The steam outlets and steam inlets of adjacent stages of the compressor are connected.

5. The steam production system as described in claim 1, characterized in that: The electric heat pump unit includes multiple stages of electric heat pumps, which are connected in series. The first and second interfaces of the low-temperature heat storage tank are respectively connected to the evaporator inlet of the first-stage electric heat pump and the evaporator outlet of the last-stage electric heat pump, and the evaporator inlet and evaporator outlet of the electric heat pumps of adjacent stages are connected. The first and second interfaces of the high-temperature heat storage tank are respectively connected to the condenser outlet of the first-stage electric heat pump and the condenser inlet of the last-stage electric heat pump, and the condenser inlets and outlets of adjacent electric heat pumps are connected.

6. The steam production system according to any one of claims 1 to 5, characterized in that: A first valve is provided in the connecting pipe of the evaporator outlet of the electric heat pump unit; a second valve is provided in the connecting pipe of the condenser inlet of the electric heat pump unit; and a third valve is provided in the pipe at at least one of the first and second interfaces of the high-temperature heat storage tank.

7. The steam production system as described in claim 6, characterized in that: The steam production system has at least one of the following operating modes: a first operating mode, a second operating mode, and a third operating mode. In the first operating mode, the first valve and the second valve are closed, the third valve is open, the electric heat pump unit stops operating, and both the low-temperature heat storage tank and the high-temperature heat storage tank are disconnected from the electric heat pump unit; In the second operating mode, the first valve, the second valve, and the third valve are all open, and the electric heat pump unit operates normally. The low-temperature heat storage tank releases heat, and the high-temperature heat storage tank stores heat. In the third operating mode, the first valve and the second valve are open, the third valve is closed, and the electric heat pump unit is partially operational. In this mode, the low-temperature heat storage tank does not release heat, and the high-temperature heat storage tank does not store heat.

8. The steam production system as described in claim 7, characterized in that: During peak electricity price periods, the steam production system operates in the first mode; during off-peak electricity price periods, the steam production system operates in the second mode; and during off-peak electricity price periods, the steam production system operates in the third mode.

9. A control method for a steam production system, the steam production system comprising a low-temperature thermal storage tank, a high-temperature thermal storage tank, a first component having a first flash evaporation unit, a second flash evaporation unit, and an electric heat pump unit, characterized in that: The control method includes: During peak electricity price periods, the steam production system is controlled to operate in a first operating mode. In the first operating mode, the electric heat pump unit is stopped, and both the low-temperature heat storage tank and the high-temperature heat storage tank are disconnected from the electric heat pump unit. The steam after flashing through the first flash unit and the high-temperature water stored in the high-temperature heat storage tank after flashing through the second flash unit enter the steam delivery pipeline together. During off-peak electricity price periods, the steam production system is controlled to operate in a second mode. In this second mode, the electric heat pump unit is controlled to operate normally. Both the low-temperature heat storage tank and the high-temperature heat storage tank are connected to the electric heat pump unit. The low-temperature water cooled by the first component mixes with the effluent from the low-temperature heat storage tank and enters the electric heat pump unit. A portion of the hot water heated by the electric heat pump unit enters the second flash evaporation unit, while the other portion is stored in the high-temperature heat storage tank. The steam after flash evaporation by the second flash evaporation unit and the steam after flash evaporation by the first flash evaporation unit both enter the steam delivery pipeline.

10. The control method as described in claim 9, characterized in that: The control method further includes: During the flat electricity price period, the steam production system is controlled to operate in a third mode. In this third mode, the electric heat pump unit is partially operated, and the electric heat pump unit is disconnected from the high-temperature heat storage tank. Low-temperature water cooled by the first component enters the electric heat pump unit, and hot water heated by the electric heat pump unit enters the second flash evaporation unit. The steam after flash evaporation in the second flash evaporation unit and the steam after flash evaporation in the first flash evaporation unit enter the steam delivery pipeline together. The low-temperature heat storage tank does not release heat, and the high-temperature heat storage tank does not store heat.

11. The control method as described in claim 9 or 10, characterized in that: The steam production system further includes a compressor unit, and the control method further includes: The steam generated by flash evaporation in either the first flash unit or the second flash unit is further compressed by the compressor unit and then enters the steam delivery pipeline.

12. The control method as described in claim 9 or 10, characterized in that: The first component also includes a heat exchange unit, and the control method further includes: Before the hot water passes through the first flash evaporation unit in the first component, it is introduced into the heat exchange unit in the first component to exchange heat with the flash return water after flash evaporation in the first flash evaporation unit. The hot water heated by the heat exchange unit then enters the first flash evaporation unit for flash evaporation. The low-temperature water cooled by the first component includes: low-temperature water cooled by heat exchange in the heat exchange unit.

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