Steam production system and method of controlling the same

Abstract

The application provides a steam production system and a control method thereof. The steam production system comprises an electric heat pump unit, a high-temperature heat storage tank and a flash unit. The electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser outlet and a condenser inlet, and the evaporator inlet and the evaporator outlet of the electric heat pump unit are respectively connected with a heat source water supply pipeline and a heat source return water pipeline. The high-temperature heat storage tank is connected with the condenser outlet and the condenser inlet of the electric heat pump unit through a first interface and a second interface. The water inlet and the water outlet of the flash unit are connected with a third interface and a fourth interface of the high-temperature heat storage tank, and the steam outlet of the flash unit is connected with a steam delivery pipeline. The application can improve the economy of the steam production system and improve the regulation ability of peak shaving and valley filling.

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:

[0007] An electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser outlet, and a condenser inlet. The evaporator inlet and evaporator outlet of the electric heat pump unit are respectively used to connect to the heat source water supply pipeline and the heat source water return pipeline.

[0008] A high-temperature heat storage tank, wherein the first interface and the second interface of the high-temperature heat storage tank are respectively connected to the condenser outlet and the condenser inlet of the electric heat pump unit;

[0009] The flash evaporation unit has its water inlet and water outlet connected to the third and fourth interfaces of the high-temperature heat storage tank, respectively, and its steam outlet is used to connect to a steam transmission pipeline.

[0010] Technical Solution 2: The steam production system as described in Technical Solution 1 further includes a low-temperature heat storage tank, wherein the electric heat pump unit is connected to the heat source supply water pipeline and the heat source return water pipeline via the low-temperature heat storage tank, wherein...

[0011] The first and second ports of the low-temperature heat storage tank are respectively connected to the heat source water supply pipeline and the heat source return water pipeline, and the third and fourth ports of the low-temperature heat storage tank are respectively connected to the evaporator inlet and evaporator outlet of the electric heat pump unit.

[0012] Technical Solution 3: In the steam production system as described in Technical Solution 2, the first and third interfaces of the low-temperature thermal storage tank are connected by a first bypass pipeline, and the second and fourth interfaces of the low-temperature thermal storage tank are connected by a second bypass pipeline; the first and third interfaces of the high-temperature thermal storage tank are connected by a third bypass pipeline, and the second and fourth interfaces of the high-temperature thermal storage tank are connected by a fourth bypass pipeline.

[0013] Technical Solution 4: The steam production system as described in Technical Solution 2, wherein the electric heat pump unit includes a multi-stage electric heat pump, and the multi-stage electric heat pump is connected in series, wherein,

[0014] The third and fourth 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 adjacent electric heat pumps are connected.

[0015] 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.

[0016] Technical Solution 5: The steam production system as described in Technical Solution 1 further includes a compressor unit, wherein the flash evaporation unit is connected to the steam delivery pipeline via the compressor unit, wherein...

[0017] The steam outlet of the flash evaporation unit is connected to the steam inlet of the compressor unit, and the steam outlet of the compressor unit is used to connect to the steam delivery pipeline.

[0018] Technical Solution 6: The steam production system as described in Technical Solution 5, wherein the flash unit includes a multi-stage flash evaporator, the multi-stage flash evaporators are connected in series, wherein the third and fourth interfaces of the high-temperature heat storage tank are respectively connected to the water inlet of the first-stage flash evaporator and the water outlet of the last-stage flash evaporator, and the water outlets and water inlets of adjacent flash evaporators are connected.

[0019] 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.

[0020] Technical Solution 7: In the steam production system as described in Technical Solution 6, the water outlet of each stage of the flash evaporator is connected to the steam outlet of the corresponding stage of the compressor.

[0021] Technical Solution 8: The steam production system as described in any one of Technical Solutions 1 to 7 further includes a normal temperature water supply pipeline and a water supply heat exchanger, wherein,

[0022] The first and second ports of the water replenishment heat exchanger are respectively used to connect to the heat source supply water pipeline and the heat source return water pipeline, the third port of the water replenishment heat exchanger is connected to the ambient temperature water replenishment pipeline, and the fourth port of the water replenishment heat exchanger is connected to the flash return water pipeline of the water outlet of the flash evaporation unit.

[0023] Technical Solution 9: The steam production system as described in any one of Technical Solutions 1 to 7 further includes a condensate recovery pipeline, wherein the condensate recovery pipeline is connected to the flash inlet pipeline of the water inlet of the flash unit.

[0024] Technical Solution 10: The steam production system as described in any one of Technical Solutions 3 to 7, wherein a first valve is provided in at least one connecting pipeline between the third interface of the low-temperature heat storage tank and the evaporator inlet of the electric heat pump unit and between the fourth interface of the low-temperature heat storage tank and the evaporator outlet of the electric heat pump unit;

[0025] A second valve is provided in at least one connecting pipeline between the first interface of the high-temperature heat storage tank and the condenser outlet of the electric heat pump unit, and between the second interface of the high-temperature heat storage tank and the condenser inlet of the electric heat pump unit.

[0026] Technical Solution 11: The steam production system as described in Technical Solution 10, wherein the steam production system has at least one operating mode selected from a first operating mode, a second operating mode, and a third operating mode, wherein...

[0027] In the first operating mode, the first valve and the second valve are closed, 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;

[0028] In the second operating mode, the first valve and the second valve are 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.

[0029] In the third operating mode, the first valve and the second valve are 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.

[0030] Technical Solution 12: The steam production system as described in Technical Solution 11 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.

[0031] Technical Solution 13: The steam production system as described in any one of Technical Solutions 2, 4 to 7, wherein the first and third interfaces of the high-temperature heat storage tank are merged into one interface, and the second and fourth interfaces of the high-temperature heat storage tank are merged into another interface; the first and third interfaces of the low-temperature heat storage tank are merged into one interface, and the second and fourth interfaces of the low-temperature heat storage tank are merged into another interface.

[0032] Technical Solution 14: A control method for a steam production system, the steam production system comprising an electric heat pump unit, a high-temperature heat storage tank, and a flash evaporation unit, the control method comprising:

[0033] During peak electricity price periods, the steam production system is controlled to operate in a first mode. In the first mode, the electric heat pump unit is stopped, the high-temperature heat storage tank is disconnected from the electric heat pump unit, and the high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the flash unit and enters the steam delivery pipeline.

[0034] 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. A portion of the hot water heated by the electric heat pump unit enters the flash evaporation unit, where it is flashed into steam and enters the steam delivery pipeline. The other portion of the hot water is stored in the high-temperature heat storage tank.

[0035] Technical Solution 15: The steam production system as described in Technical Solution 14, wherein the control method further includes:

[0036] During the flat electricity price period, the steam production system is controlled to operate in the third operating mode. In the third operating mode, the electric heat pump unit is partially operated, the electric heat pump unit is disconnected from the high-temperature heat storage tank, and the hot water heated by the electric heat pump unit directly enters the flash evaporation unit, which flashes it into steam and enters the steam delivery pipeline. The high-temperature heat storage tank does not store heat.

[0037] Technical Solution 16: The steam production system as described in Technical Solution 15, the steam production system further includes a low-temperature thermal storage tank, and the control method further includes:

[0038] In the first operating mode, the low-temperature heat storage tank is disconnected from the electric heat pump unit, and the low-temperature heat storage tank is only connected to the heat source water supply pipeline and the heat source water return pipeline. The hot water in the heat source water supply pipeline is added into the low-temperature heat storage tank, replacing the original low-temperature water in the low-temperature heat storage tank before entering the heat source water return pipeline.

[0039] In the second operating mode, the low-temperature heat storage tank is connected to the electric heat pump unit, and the hot water in the heat source water supply pipeline and the hot water in the low-temperature heat storage tank enter the electric heat pump unit together, wherein the low-temperature heat storage tank releases heat.

[0040] In the third operating mode, the low-temperature heat storage tank is disconnected from the electric heat pump unit, and only the hot water in the heat source water supply pipeline enters the electric heat pump unit, wherein the low-temperature heat storage tank does not release heat.

[0041] Technical Solution 17: The control method as described in any one of technical solutions 14 to 16, wherein the steam production system further includes a compressor unit, and the control method further includes:

[0042] The steam after flash evaporation in the flash unit is further compressed by the compressor unit and then enters the steam delivery pipeline.

[0043] The steam production system and its control method provided by one or more technical solutions of this application adopt a steam production method that consumes excess renewable energy electricity and produces steam by water transportation, thus overcoming the problem of poor economic efficiency of traditional steam production methods.

[0044] 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.

[0045] 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

[0046] Figure 1 This is a schematic diagram of the steam production system according to the first embodiment of this application.

[0047] Figure 2 This is a schematic diagram of the steam production system according to the second embodiment of this application.

[0048] Figure 3 This is a schematic diagram of the steam production system according to the third embodiment of this application.

[0049] Figure 4 This is a schematic diagram of the steam production system according to the fourth embodiment of this application.

[0050] Figure 5 This is a schematic diagram of the steam production system according to the fifth embodiment of this application.

[0051] Figure 6 This is a schematic diagram of the steam production system according to the sixth embodiment of this application.

[0052] Figure 7 This is a schematic diagram of the steam production system according to the seventh embodiment of this application.

[0053] Figure 8 This is a schematic diagram of the steam production system according to the eighth embodiment of this application.

[0054] Figure 9 This is a schematic diagram of the steam production system according to the ninth embodiment of this application.

[0055] Figure 10 This is a schematic diagram of the steam production system of this application in the first operating mode.

[0056] Figure 11 This is a schematic diagram of the steam production system of this application in the second operating mode.

[0057] Figure 12 This is a schematic diagram of the steam production system of this application in the third operating mode. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] First Embodiment

[0062] 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, an electric heat pump unit 2, a high-temperature heat storage tank 3, a flash evaporation unit 4, and a compressor unit 5.

[0063] The electric heat pump unit 2 is connected to the heat source supply water pipeline 71 and the heat source return water pipeline 72 via the low-temperature heat storage tank 1. The low-temperature heat storage tank 1 has a first interface 11, a second interface 12, a third interface 13, and a fourth interface 14. Among them, the first interface 11 and the second interface 12 of the low-temperature heat storage tank 1 are used to connect to the heat source supply water pipeline 71 and the heat source return water pipeline 72, respectively.

[0064] The electric heat pump unit 2 has an evaporator inlet, an evaporator outlet, a condenser outlet, and a condenser inlet. The third interface 13 and the fourth interface 14 of the low-temperature heat storage tank 1 are connected to the evaporator inlet and the evaporator outlet of the electric heat pump unit 2, respectively.

[0065] The high-temperature heat storage tank 3 has a first interface 31, a second interface 32, a third interface 33, and a fourth interface 34. Among them, the first interface 31 and the second interface 32 of the high-temperature heat storage tank 3 are connected to the condenser outlet and the condenser inlet of the electric heat pump unit 2, respectively.

[0066] The water inlet and water outlet of the flash evaporation unit 4 are connected to the third interface 33 and the fourth interface 34 of the high-temperature heat storage tank 3, respectively. The flash evaporation unit 4 can supply steam to the user after compression by the compressor unit 5. The steam outlet of the flash evaporation unit 4 is connected to the steam inlet of the compressor unit 5, and the steam outlet of the compressor unit 5 is used to connect to the steam delivery pipeline 73, through which steam is supplied to the user.

[0067] Second Embodiment

[0068] 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, a first valve 81 is provided in at least one connecting pipeline between the third port 13 of the low-temperature heat storage tank 1 and the evaporator inlet of the electric heat pump unit 2, and between the fourth port 14 of the low-temperature heat storage tank 1 and the evaporator outlet of the electric heat pump unit 2.

[0069] A second valve 82 is provided in at least one of the connecting pipes between the first port 31 of the high-temperature heat storage tank 3 and the condenser outlet of the electric heat pump unit 2, and between the second port 32 of the high-temperature heat storage tank 3 and the condenser inlet of the electric heat pump unit 2.

[0070] 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.

[0071] Third Embodiment

[0072] 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 In the steam production system shown, the first port 11 and the third port 13 of the low-temperature thermal storage tank 1 can be connected through the first bypass pipe, and the second port 12 and the fourth port 14 of the low-temperature thermal storage tank 1 can be connected through the second bypass pipe; the first port 31 and the third port 33 of the high-temperature thermal storage tank 3 can be connected through the third bypass pipe, and the second port 32 and the fourth port 34 of the high-temperature thermal storage tank 3 can be connected through the fourth bypass pipe.

[0073] Fourth embodiment

[0074] 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 In the steam production system shown, the electric heat pump unit 2 includes a multi-stage electric heat pump 20 connected in series. The third port 13 and the fourth port 14 of the low-temperature heat storage tank 1 are connected to the evaporator inlet of the first-stage heat pump 20 and the evaporator outlet of the last-stage heat pump 20, respectively. The evaporator inlets and outlets of adjacent heat pumps 20 are connected. Water from the third port 13 side of the low-temperature heat storage tank 1 passes sequentially through the evaporators in the multi-stage heat pump 20. The first port 31 and the second port 32 of the high-temperature heat storage tank 3 are connected to the condenser outlet of the first-stage heat pump 20 and the condenser inlet of the last-stage heat pump 20, respectively. Water from the second port 32 side of the high-temperature heat storage tank 3 passes sequentially through the condensers in the multi-stage heat pump 20 in reverse order. The condenser inlets and outlets of adjacent heat pumps 20 are connected.

[0075] Fifth Embodiment

[0076] 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 2 The difference in the steam production system shown is that, Figure 5 In the steam production system shown, the flash evaporation unit 4 has multiple flash evaporation stages and the compressor unit 5 has multiple compression stages.

[0077] Specifically, the flash unit 4 includes a multi-stage flash evaporator 40, which are connected in series, and the flash water passes through the multi-stage flash evaporator 40 in sequence. The third port 33 and the fourth port of the high-temperature heat storage tank 3 are connected to the water inlet of the first-stage flash evaporator 40 and the water outlet of the last-stage flash evaporator 40, respectively, and the water outlets and water inlets of adjacent flash evaporators 40 are connected.

[0078] The compressor unit 5 includes a multi-stage compressor 50 connected in series. The steam outlet of each flash evaporator 40 is connected to the steam inlet of the corresponding first-stage compressor 50. The steam outlets and steam inlets of adjacent compressors 50 are connected.

[0079] Sixth Embodiment

[0080] 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 5 The difference in the steam production system shown is that, Figure 6 In the steam production system shown, the multi-stage compressor 50 is designed with an interstage water spraying link, which connects the water outlet of each stage flash evaporator 40 to the steam outlet of the corresponding stage compressor 50. This allows the flash return water from the flash evaporator 40 to reduce the superheat at the outlet of the compressor 50, preventing problems such as carbonization of the compressor 50 lubricating oil and reduction of material stress.

[0081] Seventh Embodiment

[0082] When the heat storage temperature of the high-temperature heat storage tank 3 is high, the compressor unit 5 can be eliminated from the steam production system. Figure 7 A schematic diagram of the steam production system according to the seventh embodiment of this application is shown. Figure 7 As shown, Figure 7 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 7 In the steam production system shown, there is no compressor unit 5. The steam outlet of the flash unit 4 can be directly connected to the steam delivery pipeline 73 to directly generate the required steam through the flash unit 4 and supply the steam to the user through the steam delivery pipeline 73.

[0083] It is understood that the situation shown in the seventh embodiment can also be applied to other embodiments of this application.

[0084] Eighth embodiment

[0085] Since steam is continuously produced and consumed, the steam production system of this application may have a water replenishment stage. Figure 8 A schematic diagram of the steam production system according to the eighth embodiment of this application is shown. Figure 8 As shown, Figure 8 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 8 The steam production system shown may also include a normal temperature water supply pipeline 74 and a water supply heat exchanger 6.

[0086] The makeup water heat exchanger 6 has a first interface 61, a second interface 62, a third interface 63, and a fourth interface 64. The first interface 61 and the second interface 62 of the makeup water heat exchanger 6 are respectively used to connect to the heat source supply water pipeline 71 and the heat source return water pipeline 72. The third interface 63 of the makeup water heat exchanger 6 is connected to the ambient temperature makeup water pipeline 74. The fourth interface 64 of the makeup water heat exchanger 6 is connected to the flash return water pipeline of the water outlet of the flash evaporation unit 4.

[0087] The supplied hot water enters the makeup water heat exchanger 6 via the hot water supply pipeline 71, and after heat exchange, returns to the hot water return pipeline 72. Room temperature makeup water enters the makeup water heat exchanger 6 via the room temperature makeup water pipeline 74 and is heated. The heated makeup water then enters the flash evaporation return pipeline. By utilizing the heat from the supplied hot water to preheat the makeup water, compared to supplying room temperature water, electricity consumption is reduced, and overall efficiency is increased.

[0088] Ninth Embodiment

[0089] Since the latent heat of vaporization of steam is mainly utilized, the steam production system of this application includes a condensate recovery process. Figure 9 A schematic diagram of the steam production system according to the ninth embodiment of this application is shown. Figure 9 As shown, Figure 9 The steam production system shown is Figure 2 The difference in the steam production system shown is that, Figure 9 The steam production system shown may also include a condensate recovery pipeline 75.

[0090] The condensate recovery pipeline 75 is connected to the flash inlet pipeline of the water inlet of the flash evaporation unit 4.

[0091] When the temperature and grade of the condensate after the user uses steam are high, the condensate recovery pipeline 75 can be designed to connect with the flash inlet pipeline of the water inlet of the flash evaporation unit 4, so that the heat can be recovered and utilized while replenishing water.

[0092] In the above embodiments, the steam production system of this application may also omit the low-temperature heat storage tank 1 to balance the heat from the heat source. When more heat is needed, more heat is taken from the heat source, and no heat is taken during periods when no heat is needed. In the case of eliminating the low-temperature heat storage tank 1, the evaporator inlet and evaporator outlet of the electric heat pump unit 2 can be directly connected to the heat source water supply pipeline 71 and the heat source return water pipeline 72, respectively.

[0093] In the above embodiments, the low-temperature thermal storage tank 1 in the steam production system of this application can be modified from four interfaces to two interfaces. That is, the first interface 11 and the third interface 13 of the low-temperature thermal storage tank 1 can be merged into one interface, and the second interface 12 and the fourth interface 14 of the low-temperature thermal storage tank 1 can be merged into another interface. Similarly, the high-temperature thermal storage tank 3 in the steam production system of this application can also be modified from four interfaces to two interfaces. That is, the first interface 31 and the third interface 33 of the high-temperature thermal storage tank 3 can be merged into one interface, and the second interface 32 and the fourth interface 34 of the high-temperature thermal storage tank 1 can be merged into another interface. These changes do not affect the inventive substance of the steam production system of this application.

[0094] 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.

[0095] 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.

[0096] The operation mode of the steam production system of this application will be described in detail below using the scheme illustrated in the second embodiment.

[0097] During peak electricity price periods, the steam production system of this application can operate in the first mode, thus reducing electricity consumption. Figure 10 A schematic diagram of the steam production system of this application in its first operating mode is shown. (See attached diagram.) Figure 10 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 electric heat pump unit 2 stops operating, and both the low-temperature heat storage tank 1 and the high-temperature heat storage tank 3 are disconnected from the electric heat pump unit 2.

[0098] The high-temperature water stored in the high-temperature heat storage tank 3 is converted into steam by the flash evaporation unit 4, then enters the compressor unit 5 to improve its quality, and finally enters the steam delivery pipeline 73. The flash evaporation return water, whose temperature has decreased after flash evaporation, flows back into the high-temperature heat storage tank 3. At the same time, the low-temperature heat storage tank 1 is only connected to the heat source supply water pipeline 71 and the heat source return water pipeline 72. Hot water is added to the low-temperature heat storage tank 1, replacing the original low-temperature water in the low-temperature heat storage tank 1, and then enters the heat source return water pipeline 72.

[0099] 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 11 A schematic diagram of the steam production system of this application in its second operating mode is shown. (See attached diagram.) Figure 11 As shown, in the second operating mode of the steam production system of this application, the first valve 81 and the second valve 82 are open, the electric heat pump unit 2 is operating normally, and the low temperature heat storage tank 1 and the high temperature heat storage tank 3 are both connected to the electric heat pump unit 2. The low temperature heat storage tank 1 releases heat, and the high temperature heat storage tank 3 stores heat.

[0100] When the bypass of the low-temperature heat storage tank 1 is present, the heat source water supply pipeline 71 is connected in parallel with the pipeline at the third interface 13 of the low-temperature heat storage tank 1 via the bypass and enters the evaporator inlet of the electric heat pump unit 2. The evaporator outlet of the electric heat pump unit 2 is connected to the pipeline at the fourth interface 14 of the low-temperature heat storage tank 1 and the bypass of the heat source return water pipeline 72. The hot water heated by the condenser in the electric heat pump unit 2 is partially fed directly into the flash evaporation unit 4 to produce the required steam through the bypass connecting the first interface 31 and the third interface of the high-temperature heat storage tank 3. The other part is stored in the high-temperature heat storage tank 3 through the pipeline at the first interface 31 of the high-temperature heat storage tank 3 for use during periods of high electricity price. The flash return water pipeline of the water outlet of the flash evaporation unit 4 is connected to the electric heat pump unit 2 through the bypass connecting the second interface 32 and the fourth interface of the high-temperature heat storage tank 3.

[0101] During periods of flat electricity pricing, the steam production system of this application operates in the third mode. Figure 12 A schematic diagram of the steam production system of this application in the third operating mode is shown. (See attached diagram.) Figure 12 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 closed, the electric heat pump unit 2 is running, wherein the low temperature heat storage tank 1 does not release heat, and the high temperature heat storage tank 3 does not store heat.

[0102] When the bypass of the low-temperature heat storage tank 1 is present, the heat source water supply line 71 directly enters the evaporator inlet of the electric heat pump unit 2 through the bypass, and the evaporator outlet of the electric heat pump unit 2 is connected to the bypass of the heat source return water line 72; the hot water heated by the condenser in the electric heat pump unit 2 directly enters the flash evaporation unit 4 to produce the required steam through the bypass connecting the first interface 31 and the third interface 33 of the high-temperature heat storage tank 3, and the flash return water line of the water outlet of the flash evaporation unit 4 is connected to the electric heat pump unit 2 through the bypass connecting the second interface 32 and the fourth interface 34 of the high-temperature heat storage tank 3.

[0103] The steam production system of this application changes the steam production path by adjusting the operating strategy during different electricity consumption periods. During periods of high electricity price, the high-temperature water stored in the high-temperature heat storage tank 3 is used to produce the required steam through flash evaporation. During periods of low electricity price, the electric heat pump unit 2 is used to recover the low-temperature water heat from the low-temperature heat storage tank 1, storing heat in the high-temperature heat storage tank 3 while simultaneously producing the required steam.

[0104] The steam production system of this application consumes electricity during periods of low electricity price and reduces electricity consumption during periods of high electricity price. While realizing the function of peak shaving and valley filling and assisting in the regulation of the power system, it reduces operating costs, improves economic efficiency, and broadens the application scenarios of water transmission for steam production by utilizing the peak-valley electricity price difference at the user end.

[0105] This application also provides a control method for a steam production system. The steam production system includes an electric heat pump unit 2, a high-temperature heat storage tank 3, and a flash evaporation unit 4. The control method for the steam production system of this application may include steps S1 to S2.

[0106] In step S1, in conjunction with reference Figure 10 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 2 is stopped, the high-temperature heat storage tank 3 is disconnected from the electric heat pump unit 2, and the high-temperature water stored in the high-temperature heat storage tank 3 is flashed into steam by the flash unit 4 and enters the steam delivery pipeline 73.

[0107] In step S2, in conjunction with reference Figure 11 As shown, during off-peak electricity price periods, the steam production system can be controlled to operate in the second mode. In the second mode, the electric heat pump unit 2 is controlled to operate normally. A portion of the hot water heated by the electric heat pump unit 2 enters the flash evaporation unit 4 and is flashed into steam by the flash evaporation unit 4, which then enters the steam delivery pipeline 73. The other portion of the hot water is stored in the high-temperature heat storage tank 3.

[0108] In some embodiments, the control method of the steam production system of this application may further include step S3.

[0109] In step S3, in conjunction with reference Figure 12 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 2 is partially operated, the electric heat pump unit 2 is disconnected from the high temperature heat storage tank 3, and the hot water heated by the electric heat pump unit 2 directly enters the flash evaporation unit 4, which flashes into steam and enters the steam delivery pipeline 73. The high temperature heat storage tank 3 does not store heat.

[0110] The steam production system may also include a low-temperature thermal storage tank 1. Therefore, in some embodiments, step S1 may further include: in a first operating mode, the low-temperature thermal storage tank 1 is disconnected from the electric heat pump unit 2, and hot water from the heat source supply water pipeline 71 replenishes the low-temperature thermal storage tank 1, replacing the original low-temperature water in the tank before entering the heat source return water pipeline 72. Step S2 may further include: in a second operating mode, the low-temperature thermal storage tank 1 is connected to the electric heat pump unit 2, and the hot water from the heat source supply water pipeline 71 and the hot water from the low-temperature thermal storage tank 1 enter the electric heat pump unit 2 together, wherein the low-temperature thermal storage tank 1 releases heat. Step S3 may further include: in a third operating mode, the low-temperature thermal storage tank 1 is disconnected from the electric heat pump unit 2, and only the hot water from the heat source supply water pipeline 71 enters the electric heat pump unit 2, wherein the low-temperature thermal storage tank 1 does not release heat.

[0111] The steam production system may also include a compressor unit 5. Therefore, in some embodiments, the control method of the steam production system of this application may further include step S4.

[0112] In step S4, the steam after flashing in the flash unit 4 can be further compressed by the compressor unit 5 and then enter the steam delivery pipeline 73.

[0113] The control method of the steam production system proposed in this application adopts a steam production method that consumes excess renewable energy electricity and produces steam by water transportation, thus overcoming the problem of poor economic efficiency of traditional steam production methods.

[0114] The control method of the steam production system in this application utilizes a high-temperature thermal storage tank 3, a low-temperature thermal storage tank 1, and an electric heat pump unit 2 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.

[0115] The control method for the steam production system in this application improves 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. This results in higher electricity consumption during periods of low electricity prices and lower electricity consumption during periods of high electricity prices.

[0116] 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: include: An electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser outlet, and a condenser inlet. The evaporator inlet and evaporator outlet of the electric heat pump unit are respectively used to connect to the heat source water supply pipeline and the heat source water return pipeline. A high-temperature heat storage tank, wherein the first interface and the second interface of the high-temperature heat storage tank are respectively connected to the condenser outlet and the condenser inlet of the electric heat pump unit; The flash evaporation unit has its water inlet and water outlet connected to the third and fourth interfaces of the high-temperature heat storage tank, respectively, and its steam outlet is used to connect to a steam transmission pipeline. A low-temperature thermal storage tank is provided, through which the electric heat pump unit is connected to the heat source supply water pipeline and the heat source return water pipeline. The first and second ports of the low-temperature thermal storage tank are respectively connected to the heat source supply water pipeline and the heat source return water pipeline. The third and fourth ports of the low-temperature thermal storage tank are respectively connected to the evaporator inlet and evaporator outlet of the electric heat pump unit. The first and third ports of the low-temperature thermal storage tank are connected via a first bypass pipeline, and the second and fourth ports of the low-temperature thermal storage tank are connected via a second bypass pipeline. Similarly, the first and third ports of the high-temperature thermal storage tank are connected via a third bypass pipeline, and the second and fourth ports of the high-temperature thermal storage tank are connected via a fourth bypass pipeline. A first valve is provided in at least one connecting pipe between the third port of the low-temperature heat storage tank and the evaporator inlet of the electric heat pump unit, and between the fourth port of the low-temperature heat storage tank and the evaporator outlet of the electric heat pump unit; a second valve is provided in at least one connecting pipe between the first port of the high-temperature heat storage tank and the condenser outlet of the electric heat pump unit, and between the second port of the high-temperature heat storage tank and the condenser inlet of the electric heat pump unit. The steam production system includes a first operating mode, a second operating mode, and a third operating mode. In the first operating mode, the first and second valves are closed, the electric heat pump unit stops operating, and both the low-temperature and high-temperature heat storage tanks are disconnected from the electric heat pump unit. The high-temperature water stored in the high-temperature heat storage tank is flashed into steam via the flash evaporation unit and enters the steam delivery pipeline. In the second operating mode, the first and second valves are open, the electric heat pump unit operates normally, the low-temperature heat storage tank releases heat, and the high-temperature heat storage tank stores heat. A portion of the hot water heated by the electric heat pump unit enters the flash evaporation unit, where it is flashed into steam and enters the steam delivery pipeline. The remaining hot water is stored in the high-temperature heat storage tank. In the third operating mode, the first and second valves are closed, the electric heat pump unit operates partially, and the low-temperature heat storage tank does not release heat, and the high-temperature heat storage tank does not store heat. 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.

2. 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 third and fourth 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 adjacent electric heat pumps 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.

3. The steam production system as described in claim 1, characterized in that: It also includes a compressor unit, through which the flash evaporation unit is connected to the steam delivery pipeline, wherein, The steam outlet of the flash evaporation unit is connected to the steam inlet of the compressor 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 flash unit includes a multi-stage flash evaporator, which is connected in series. The third and fourth ports of the high-temperature heat storage tank are connected to the water inlet of the first-stage flash evaporator and the water outlet of the last-stage flash evaporator, respectively. The water outlets and water inlets of 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 4, characterized in that: The water outlet of each stage of the flash evaporator is connected to the steam outlet of the corresponding stage of the compressor.

6. The steam production system according to any one of claims 1 to 5, characterized in that: It also includes ambient temperature water supply pipelines and water supply heat exchangers, among which, The first and second ports of the water replenishment heat exchanger are respectively used to connect to the heat source supply water pipeline and the heat source return water pipeline, the third port of the water replenishment heat exchanger is connected to the ambient temperature water replenishment pipeline, and the fourth port of the water replenishment heat exchanger is connected to the flash return water pipeline of the water outlet of the flash evaporation unit.

7. The steam production system according to any one of claims 1 to 5, characterized in that: It also includes a condensate recovery pipeline, wherein the condensate recovery pipeline is connected to the flash inlet pipeline of the water inlet of the flash evaporation unit.

8. The steam production system as described in claim 1, characterized in that: The first and third interfaces of the high-temperature thermal storage tank are merged into one interface, and the second and fourth interfaces of the high-temperature thermal storage tank are merged into another interface; the first and third interfaces of the low-temperature thermal storage tank are merged into one interface, and the second and fourth interfaces of the low-temperature thermal storage tank are merged into another interface.

9. A control method for a steam production system as described in claim 1, characterized in that: The control method includes: During peak electricity price periods, the steam production system is controlled to operate in a first mode. In this first mode, the electric heat pump unit is stopped, and both the low-temperature and high-temperature heat storage tanks are disconnected from the electric heat pump unit. The low-temperature heat storage tank is only connected to the heat source supply water pipeline and the heat source return water pipeline. Hot water from the heat source supply water pipeline is introduced into the low-temperature heat storage tank to replace the original low-temperature water in the tank before entering the heat source return water pipeline. The high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the flash unit and enters the steam delivery pipeline. 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. Hot water in the heat source water supply pipeline and hot water in the low-temperature heat storage tank enter the electric heat pump unit together. The low-temperature heat storage tank releases heat, and a portion of the hot water heated by the electric heat pump unit enters the flash evaporation unit, where it is flashed into steam and enters the steam delivery pipeline. The other portion of the hot water is stored in the high-temperature heat storage tank. During the flat electricity price period, the steam production system is controlled to operate in the third operating mode. In the third operating mode, the electric heat pump unit is partially operated, and both the low-temperature heat storage tank and the high-temperature heat storage tank are disconnected from the electric heat pump unit. Only the hot water in the heat source water supply pipeline enters the electric heat pump unit. The low-temperature heat storage tank does not release heat. The hot water heated by the electric heat pump unit directly enters the flash evaporation unit, where it is flashed into steam and enters the steam delivery pipeline. The high-temperature heat storage tank does not store heat.

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

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