Steam production system and its control method

Abstract

This application provides a steam production system and its control method. The system includes 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 a heat source water supply pipeline; the electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser inlet, and a condenser outlet, wherein the evaporator inlet of the electric heat pump unit is connected to the water outlet of the first component, and the evaporator outlet of the electric heat pump unit is used to connect to a heat source return water pipeline; the first and second interfaces of the high-temperature heat storage tank are respectively connected to the condenser outlet and condenser inlet of the electric heat pump unit, and the third and fourth interfaces of the high-temperature heat storage tank are respectively connected to the water inlet and 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 a 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 economy of the steam production system and enhance the 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 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 an inlet and an 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 electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser inlet, and a condenser outlet. The evaporator inlet of the electric heat pump unit is connected to the water outlet of the first component, and the evaporator outlet of the electric heat pump unit is used to connect to the heat source return water pipeline.

[0009] The first and second ports of the high-temperature heat storage tank are respectively connected to the condenser outlet and condenser inlet of the electric heat pump unit, and the third and fourth ports of the high-temperature heat storage tank are respectively connected to the water inlet and 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 any one of Technical Solutions 1 to 4 further includes a low-temperature heat storage tank, wherein the water inlet of the first component and the evaporator outlet of the electric heat pump unit are respectively connected to the heat source supply water pipeline and the heat source return water pipeline through the low-temperature heat storage tank, wherein,

[0018] The first and second interfaces of the low-temperature heat storage tank are respectively used to connect to the heat source water supply pipeline and the heat source return water pipeline, and the third and fourth interfaces of the low-temperature heat storage tank are respectively connected to the water inlet of the first component and the evaporator outlet of the electric heat pump unit.

[0019] Technical Solution 6: The steam production system as described in Technical Solution 5, wherein a first valve is provided in the pipeline at at least one of the first and second interfaces of the low-temperature thermal storage tank, and a second valve is provided in the pipeline at at least one of the third and fourth interfaces of the low-temperature thermal storage tank.

[0020] Technical Solution 7: In the steam production system described in Technical Solution 6, 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, wherein a third valve is provided in the first bypass pipeline and the second bypass pipeline.

[0021] Technical Solution 8: The steam production system as described in Technical Solution 7, wherein the steam production system has a first operating mode and a second operating mode, wherein,

[0022] In the first operating mode, the first valve is open, the second valve and the third valve are closed, the electric heat pump unit stops operating, the first component does not operate, and the high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the second flash unit and enters the steam delivery pipeline.

[0023] In the second operating mode, the first valve is closed, the second valve and the third valve are open, the electric heat pump unit operates normally, the first component operates, and the second flash unit does not operate. The low-temperature heat storage tank releases heat, and the high-temperature heat storage tank stores heat.

[0024] Technical Solution 9: The steam production system as described in Technical Solution 8 operates in the first mode during peak electricity price periods and in the second mode during off-peak electricity price periods.

[0025] Technical Solution 10: In the steam production system described in Technical Solution 5, 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.

[0026] Technical Solution 11: A control method for a steam production system, the steam production system comprising 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 control method comprising:

[0027] During peak electricity price periods, the steam production system is controlled to operate in a first operating mode. In this first operating mode, the electric heat pump unit is stopped, the first component is not operated, and the high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the second flash unit and enters the steam delivery pipeline.

[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 operates normally, the second flash unit does not operate, and hot water is flashed into steam by the first flash unit in the first component and enters the steam delivery pipeline. The low-temperature water cooled by the first component enters the electric heat pump unit, and the hot water heated by the electric heat pump unit is stored in the high-temperature heat storage tank.

[0029] Technical Solution 12: The control method as described in Technical Solution 11, wherein the steam production system further includes a compressor unit, and the control method further includes:

[0030] 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.

[0031] Technical Solution 13: The control method as described in Technical Solution 11, wherein the first component further comprises a heat exchange unit, and the control method further comprises:

[0032] 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.

[0033] The process of the low-temperature water cooled by the first component entering the electric heat pump unit includes: the low-temperature water cooled by heat exchange in the heat exchange unit entering the electric heat pump unit.

[0034] Technical Solution 14: The control method as described in any one of technical solutions 11 to 13, wherein the steam production system further includes a cryogenic heat storage tank, and the control method further includes:

[0035] In the first operating mode, the low-temperature heat storage tank is controlled to be connected only 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 replenished 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.

[0036] In the second operating mode, the hot water in the heat source water supply pipeline and the hot water in the low-temperature heat storage tank enter the first component together, wherein the low-temperature heat storage tank releases heat.

[0037] 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.

[0038] 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.

[0039] 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

[0040] Figure 1 This is a schematic diagram of the steam production system according to the first embodiment of this application.

[0041] Figure 2 This is a schematic diagram of the steam production system according to the second embodiment of this application.

[0042] Figure 3 This is a schematic diagram of the steam production system according to the third embodiment of this application.

[0043] Figure 4 This is a schematic diagram of the steam production system according to the fourth embodiment of this application.

[0044] Figure 5 This is a schematic diagram of the steam production system according to the fifth embodiment of this application.

[0045] Figure 6 This is a schematic diagram of the steam production system according to the sixth embodiment of this application.

[0046] Figure 7 This is a schematic diagram of the steam production system according to the seventh embodiment of this application.

[0047] Figure 8 This is a schematic diagram of the steam production system of this application in the first operating mode.

[0048] Figure 9 This is a schematic diagram of the steam production system of this application in the second operating mode. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] 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.

[0052] First Embodiment

[0053] 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.

[0054] The first component 2 has an inlet 201 and an 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 respectively connected to the inlet 201 and the outlet 202 of the first component 2.

[0055] The electric heat pump unit 4 has an evaporator inlet, an evaporator outlet, a condenser inlet, and a condenser outlet, wherein the evaporator inlet of the electric heat pump unit 4 is connected to the water outlet 202 of the first component 2.

[0056] The inlet 201 of the first component 2 and the evaporator outlet of the electric heat pump unit 4 can be connected to the heat source supply water pipeline 71 and the heat source return water pipeline 72, respectively, through 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, and the third interface 13 and the fourth interface 14 of the low-temperature heat storage tank 1 are connected to the inlet 201 of the first component 2 and the evaporator outlet of the electric heat pump unit 4, respectively.

[0057] The high-temperature heat storage tank 5 has a first interface 51, a second interface 52, a third interface 53, and a fourth interface 54. The first interface 51 and the second interface 52 of the high-temperature heat storage tank 5 are respectively connected to the condenser outlet and the condenser inlet of the electric heat pump unit 4, and the third interface 53 and the fourth interface 54 of the high-temperature heat storage tank 5 are respectively connected to the water inlet and the water outlet of the second flash evaporation unit 3.

[0058] 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.

[0059] Second Embodiment

[0060] 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.

[0061] 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.

[0062] Third Embodiment

[0063] Figure 3A 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, a first valve 81 is provided in the pipeline at at least one of the first interface 11 and the second interface 12 of the low-temperature thermal storage tank 1, and a second valve 82 is provided in the pipeline at at least one of the third interface 13 and the fourth interface 14 of the low-temperature thermal storage tank 1.

[0064] Optionally, the first port 11 and the third port 13 of the cryogenic thermal storage tank 1 are connected through a first bypass pipe, and the second port 12 and the fourth port 14 of the cryogenic thermal storage tank 1 are connected through a second bypass pipe. A third valve 83 is provided in the first bypass pipe and the second bypass pipe.

[0065] 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.

[0066] Fourth embodiment

[0067] 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 3 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 first flash evaporation unit 21, and the steam outlet of the compressor unit 6 is used to connect to the steam delivery pipeline 73.

[0068] 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.

[0069] Fifth embodiment

[0070] 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 3 The difference in the steam production system shown is that, Figure 5The 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.

[0071] 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.

[0072] 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.

[0073] Sixth Embodiment

[0074] 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 second flash unit 3 has multiple flash stages and the compressor unit 6 has multiple compression stages.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] Alternatively, the first flash unit 21 of this application may also have a multi-stage flash process.

[0079] Therefore, either the first flash unit 21 or the second flash unit 3 of this application can include a multi-stage flash evaporator 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 60.

[0080] Seventh Embodiment

[0081] 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 The steam production system shown can be configured without a 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 water inlet 201 of the first component 2 is used to connect directly to the heat source water supply pipeline 71, and the evaporator outlet of the electric heat pump unit 4 is used to connect directly to the heat source return water pipeline 72.

[0082] The absence of a cryogenic thermal storage tank 1 can also be applied to other embodiments of this application.

[0083] In the above embodiments, the electric heat pump unit 4 can be designed as a multi-stage unit, which may include a multi-stage electric heat pump connected in series. The outlet 202 of the first component 2 and the fourth interface 14 of the low-temperature heat storage tank 1 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. The evaporator inlets and outlets of adjacent electric heat pumps are connected. The water outlet 202 of the first component 2 passes through the evaporators in the multi-stage electric heat pump in sequence. The first interface 51 and the second interface 52 of the high-temperature heat storage tank 5 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. The water outlet 52 of the high-temperature heat storage tank 5 passes through the condensers in the multi-stage electric heat pump in reverse order. The condenser inlets and outlets of adjacent electric heat pumps are connected.

[0084] 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 5 in the steam production system of this application can also be modified from four interfaces to two interfaces. That is, the first interface 51 and the third interface 53 of the high-temperature thermal storage tank 5 can be merged into one interface, and the second interface 52 and the fourth interface 54 of the high-temperature thermal storage tank 5 can be merged into another interface. These changes do not affect the inventive substance of the steam production system of this application.

[0085] 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.

[0086] In some embodiments, the steam production system of this application may have a first operating mode and a second operating mode.

[0087] The operation mode of the steam production system of this application will be described in detail below using the scheme illustrated in the third embodiment.

[0088] During peak electricity price periods, the steam production system of this application can operate in the first mode, thus reducing electricity consumption. Figure 8 A schematic diagram of the steam production system of this application in its first operating mode is shown. (See attached diagram.) Figure 8 As shown, in the first operating mode of the steam production system of this application, the electric heat pump unit 4 stops operating, the first valve 81 is open, the second valve 82 is closed (when the low-temperature heat storage tank 1 bypass exists, the third valve 83 is also closed), the first component 2 does not operate, the high-temperature water stored in the high-temperature heat storage tank 5 generates steam through the second flash evaporation unit 3, and enters the steam delivery pipeline 73. The flash evaporation return water, whose temperature has decreased after flash evaporation, flows back to the high-temperature heat storage tank 5. 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.

[0089] 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 9 A schematic diagram of the steam production system of this application in its second operating mode is shown. (See attached diagram.) Figure 9 As shown, in the second operating mode of the steam production system of this application, the electric heat pump unit 4 is operating normally.

[0090] The first valve 81 is closed, the second valve 82 is open (when the bypass of the low-temperature heat storage tank 1 exists, the third valve 83 is also open), the first component 2 is running, and the second flash unit 3 is not running. The low-temperature heat storage tank 1 releases heat, and the high-temperature heat storage tank 5 stores heat.

[0091] The heat source water supply pipeline 71 is bypassed and connected in parallel with the pipeline at the third interface 13 of the low-temperature heat storage tank 1, entering the first interface 221 of the heat exchange unit 22. After the hot water is cooled by heat exchange, it enters the evaporator inlet and evaporator outlet of the electric heat pump unit 4. After the water temperature decreases, part of the return water returns to the low-temperature heat storage tank 1 through the fourth interface 14, pushing the hot water in the low-temperature heat storage tank 1 out through its third interface 13. The other part of the return water returns directly to the heat source return water pipeline 72. The hot water heated by the heat exchange unit 22 enters the first flash evaporation unit 21 to produce steam. The hot water heated by the condenser in the electric heat pump unit 4 is sent out from the condenser outlet of the electric heat pump unit 4 and stored in the high-temperature heat storage tank 5 for use during periods of high electricity prices.

[0092] When the bypass of the low-temperature thermal storage tank 1 is not present, hot water flows from the heat source supply pipe 71 through the low-temperature thermal storage tank 1. The heat source supply water and the hot water in the low-temperature thermal storage tank 1 flow out from the third port 13 of the low-temperature thermal storage tank 1 and enter the first port 221 of the heat exchange unit 22. After being cooled by the heat exchange unit 22 and the electric heat pump unit 4, the water temperature decreases, and all the water returns to the fourth port 14 of the low-temperature thermal storage tank 1. A portion of the water returns directly to the heat source return pipe 72 through the low-temperature thermal storage tank 1, while the other portion pushes outwards towards the top of the low-temperature thermal storage tank 1, pushing the supply water in the low-temperature thermal storage tank 1 out from the third port 13. The hot water heated by the heat exchange unit 22 enters the first flash evaporation unit 21 to produce steam. The hot water heated by the condenser in the electric heat pump unit 4 is sent out from the condenser outlet of the electric heat pump unit 4 and stored in the high-temperature thermal storage tank 5 for use during periods of high electricity prices.

[0093] The steam production system of this application adopts different operating strategies during different electricity price periods. When the electricity price is high, the system consumes less electricity and uses high-temperature water stored in a high-temperature heat storage tank to produce steam. During periods of low electricity price, an electric heat pump is used to recover the heat from the low-temperature water in a low-temperature heat storage tank, storing heat in the high-temperature heat storage tank while simultaneously producing the required steam.

[0094] The steam production system of this application can utilize high-temperature hot water in stages to produce steam, thereby improving the utilization efficiency of high-temperature hot water, increasing the amount of steam produced, absorbing electricity during periods of low electricity price and reducing 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 also reduces operating costs, improves economic efficiency, and broadens the application scenarios of water transmission for steam production.

[0095] This application also provides a control method for a steam production system. The steam production system may include 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.

[0096] In step S1, in conjunction with reference Figure 8 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, the first component 2 is not operated, and the high-temperature water stored in the high-temperature heat storage tank 5 is flashed into steam by the second flash unit 3 and enters the steam transmission pipeline 73.

[0097] In step S2, in conjunction with reference Figure 9 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 4 is controlled to operate normally, the second flash unit 3 is not operated, and the hot water is flashed into steam by the first flash unit 21 in the first component 2 and enters the steam delivery pipeline 73. The low-temperature water after being cooled by the first component 2 enters the electric heat pump unit 4, and the hot water heated by the electric heat pump unit 4 is stored in the high-temperature heat storage tank 5.

[0098] 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 S3.

[0099] In step S3, 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.

[0100] 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 S4.

[0101] In step S4, 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 enters the first flash unit 21 for flashing.

[0102] When the first component 2 has a heat exchange unit 22, the low-temperature water cooled by the first component 2 enters the electric heat pump unit 4, which includes: the low-temperature water cooled by heat exchange unit 22 enters the electric heat pump unit 4.

[0103] In the absence of a heat exchange unit 22 in the first component 2, the low-temperature water cooled by the first component 2 enters the electric heat pump unit 4, including: the flash return water after flashing by the first flash unit 21 enters the electric heat pump unit 4.

[0104] 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, controlling the low-temperature thermal storage tank 1 to be connected only to the heat source supply water pipeline 71 and the heat source return water pipeline 72, with hot water from the heat source supply water pipeline 71 supplementing the low-temperature thermal storage tank 1, replacing the original low-temperature water in the low-temperature thermal storage tank 1, and then entering the heat source return water pipeline 72. Step S2 may further include: in a second operating mode, the hot water from the heat source supply water pipeline 71 and the hot water from the low-temperature thermal storage tank 1 jointly enter the first component 2, wherein the low-temperature thermal storage tank 1 releases heat.

[0105] 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.

[0106] The control method of the steam production system in 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.

[0107] 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.

[0108] 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 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 electric heat pump unit has an evaporator inlet, an evaporator outlet, a condenser inlet, and a condenser outlet. The evaporator inlet of the electric heat pump unit is connected to the water outlet of the first component, and the evaporator outlet of the electric heat pump unit is used to connect to the heat source return water pipeline. The first and second ports of the high-temperature heat storage tank are respectively connected to the condenser outlet and condenser inlet of the electric heat pump unit, and the third and fourth ports of the high-temperature heat storage tank are respectively connected to the water inlet and 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 according to any one of claims 1 to 4, characterized in that: It also includes a low-temperature heat storage tank, wherein the water inlet of the first component and the evaporator outlet of the electric heat pump unit are respectively connected to the heat source supply water pipeline and the heat source return water pipeline through the low-temperature heat storage tank, wherein, The first and second interfaces of the low-temperature heat storage tank are respectively used to connect to the heat source water supply pipeline and the heat source return water pipeline, and the third and fourth interfaces of the low-temperature heat storage tank are respectively connected to the water inlet of the first component and the evaporator outlet of the electric heat pump unit.

6. The steam production system as described in claim 5, characterized in that: A first valve is provided in the pipeline at at least one of the first and second interfaces of the cryogenic thermal storage tank, and a second valve is provided in the pipeline at at least one of the third and fourth interfaces of the cryogenic thermal storage tank.

7. The steam production system as described in claim 6, characterized in that: The first and third ports of the cryogenic thermal storage tank are connected by a first bypass pipeline, and the second and fourth ports of the cryogenic thermal storage tank are connected by a second bypass pipeline. A third valve is provided in the first and second bypass pipelines.

8. The steam production system as described in claim 7, characterized in that: The steam production system has a first operating mode and a second operating mode, wherein, In the first operating mode, the first valve is open, the second valve and the third valve are closed, the electric heat pump unit stops operating, the first component does not operate, and the high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the second flash unit and enters the steam delivery pipeline. In the second operating mode, the first valve is closed, the second valve and the third valve are open, the electric heat pump unit operates normally, the first component operates, and the second flash unit does not operate. The low-temperature heat storage tank releases heat, and the high-temperature heat storage tank stores heat.

9. The steam production system as described in claim 8, 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.

10. The steam production system as described in claim 5, 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.

11. A control method for a steam production system, the steam production system comprising 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, 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 this first operating mode, the electric heat pump unit is stopped, the first component is not operated, and the high-temperature water stored in the high-temperature heat storage tank is flashed into steam by the second 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 operates normally, the second flash unit does not operate, and hot water is flashed into steam by the first flash unit in the first component and enters the steam delivery pipeline. The low-temperature water cooled by the first component enters the electric heat pump unit, and the hot water heated by the electric heat pump unit is stored in the high-temperature heat storage tank.

12. The control method as described in claim 11, 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.

13. The control method as described in claim 11, 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 process of the low-temperature water cooled by the first component entering the electric heat pump unit includes: the low-temperature water cooled by heat exchange in the heat exchange unit entering the electric heat pump unit.

14. The control method according to any one of claims 11 to 13, characterized in that: The steam production system also includes a cryogenic thermal storage tank, and the control method further includes: In the first operating mode, the low-temperature heat storage tank is controlled to be connected only 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 replenished 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. In the second operating mode, the hot water in the heat source water supply pipeline and the hot water in the low-temperature heat storage tank enter the first component together, wherein the low-temperature heat storage tank releases heat.

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