Power generation system integrating double-drum heat storage and exhaust steam waste heat recovery

Abstract

The utility model discloses a kind of double steam pocket heat storage and waste heat recovery integrated power generation system, including first fire cabinet, second fire cabinet, first steam pocket, circulating pump, waste heat boiler, second steam pocket, steam main pipe, heat accumulator, steam turbine, generator, soft water tank, feed water pump, high-temperature phase change energy storage device and waste heat recovery system;Three-way interface is provided on main pipeline, one interface is connected to the steam inlet of high-temperature phase change energy storage device by branch pipeline, and the steam outlet of high-temperature phase change energy storage device is connected to the other input end of heat accumulator by another branch pipeline, to form and return circuit;Waste heat recovery system at least includes plate heat exchanger and circulating water pump, when smelting furnace normal operation, excess steam can be stored into phase change energy storage device, during shutdown, the high-temperature phase change energy storage device can release stored heat energy, continuously and stably produce steam, extend the continuous power generation time of generator, ensure the continuity and stability of power generation.

Description

Technical Field

[0001] This utility model relates to the technology of waste heat power generation, and in particular to a power generation system that integrates dual steam drum heat storage and waste steam heat recovery. Background Technology

[0002] In the pyrometallurgical antimony smelting process, the blast furnace generates a large amount of high-temperature flue gas (about 1000-1300℃). The traditional process uses multiple fireboxes and surface coolers to cool the flue gas and recover antimony white powder (Sb2O3). In this process, a large amount of high-temperature heat is directly wasted, resulting in low energy utilization efficiency.

[0003] To improve energy efficiency, existing technologies employ waste heat power generation systems, which include converting No. 1 and No. 2 fire cabinets into vaporization cooling modes and setting up independent fire cabinet system steam drums; eliminating No. 3 fire cabinet and surface cooler, and adding a waste heat boiler and its steam drum; the steam generated by the two steam drums is fed into the steam header, and then transported to the steam turbine generator set for power generation after being stabilized by a heat accumulator.

[0004] However, the above-mentioned waste heat power generation system still has obvious defects: for example, the smelting furnace (antimony smelting blast furnace) needs to be shut down periodically for ash removal, which leads to the interruption of heat source and fluctuations in steam production. Although a heat accumulator is installed, its traditional heat storage capacity is limited, making it difficult to maintain the stable operation of the steam turbine during long-term shutdowns, which affects the continuity of power generation and grid connection quality.

[0005] Secondly, the system has a single energy utilization mode, focusing only on power generation, while failing to effectively recover the large amount of medium and low temperature waste heat carried by the exhaust steam (or intermediate extraction steam) after the steam turbine has finished its work. This part of the heat is eventually carried away and dissipated by the circulating water through the condenser, resulting in secondary waste of energy.

[0006] Therefore, a new technical solution needs to be researched to address the above problems. Utility Model Content

[0007] In view of this, the present invention addresses the deficiencies of the existing technology and its main objective is to provide a power generation system integrating dual steam drum heat storage and waste steam heat recovery. This system connects a high-temperature phase change energy storage device in parallel between the steam header and the heat accumulator. Thus, during normal operation of the smelting furnace (antimony smelting blast furnace), excess steam can be stored in the phase change energy storage device. During furnace shutdown, the high-temperature phase change energy storage device can release the stored heat energy to continuously and stably generate steam, extending the generator's continuous power generation time and ensuring the continuity and stability of power generation.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A power generation system integrating dual-steam-drum thermal storage and waste heat recovery includes a first heat exchanger, a second heat exchanger, a first steam drum, a circulating pump, a waste heat boiler, a second steam drum, a steam header, a heat accumulator, a steam turbine, a generator, a soft water tank, and a feedwater pump. The output ends of the first and second heat exchangers are connected to the input ends of the first steam drum. The first output end of the first steam drum is connected to the first input ends of the first and second heat exchangers, respectively. The second output end of the first steam drum is connected to the input end of the steam header. The output end of the steam header is connected to the input end of the heat accumulator via a main pipeline. The output end of the heat accumulator is connected to the steam turbine, and the output end of the steam turbine is connected to the input end of the generator. The steam turbine is connected to the soft water tank, the soft water tank is connected to the feedwater pump, and the output end of the feedwater pump is connected to the second input ends of the waste heat boiler, the first heat exchanger, and the second heat exchanger, respectively.

[0010] It also includes a high-temperature phase change energy storage device and a waste heat recovery system; the main pipeline is equipped with a three-way interface, one of which is connected to the steam inlet of the high-temperature phase change energy storage device through a branch pipeline, and the steam outlet of the high-temperature phase change energy storage device is connected to the other input end of the heat accumulator through another branch pipeline to form a parallel loop.

[0011] The waste heat recovery system includes at least a plate heat exchanger and a circulating water pump. The exhaust port of the steam turbine is connected to the primary inlet of the plate heat exchanger via an exhaust pipe, and the primary outlet of the plate heat exchanger is connected to a soft water tank. The secondary inlet of the plate heat exchanger is connected to the circulating water pump. The inlet of the hot water circulating pump is used to connect to the plant's heating return water, and the secondary outlet of the plate heat exchanger is used to provide heating or process hot water to the plant.

[0012] As a preferred embodiment, the front end of the three-way interface is also equipped with an electric check valve to prevent steam backflow to the waste heat boiler; a first electric regulating valve is also installed on the steam inlet of the branch pipe and the high-temperature phase change energy storage device, and a second electric regulating valve is also installed on the steam outlet of the other branch pipe and the high-temperature phase change energy storage device. Through the coordinated action of the electric check valve, the electric regulating valve and the control device, the flow direction and distribution of steam in different modes such as power generation, energy storage and energy release can be intelligently controlled according to parameters such as steam pressure and temperature.

[0013] As a preferred embodiment, the exhaust port of the steam turbine generator set is connected to a condenser, and the outlet of the condenser is connected to the soft water tank.

[0014] As a preferred embodiment, a water preheating system is also provided between the soft water tank and the water supply pump. The water preheating system includes a solar heat exchanger. The outlet of the soft water tank is connected to the cold side inlet of the solar heat exchanger, and the cold side outlet of the solar heat exchanger is connected to the input end of the water supply pump, thereby achieving coupling with clean energy and further reducing system energy consumption.

[0015] As a preferred embodiment, a temperature sensor is installed at the cold-side outlet of the solar heat exchanger.

[0016] As a preferred embodiment, the water preheating system is further provided with a control device, which is electrically connected to a temperature sensor, an electric check valve, a first electric regulating valve, and a second electric regulating valve.

[0017] Compared with the prior art, this utility model has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution, it mainly connects a high-temperature phase change energy storage device in parallel between the steam header and the accumulator. In this way, when the smelting furnace (antimony smelting blast furnace) is running normally, excess steam can be stored in the phase change energy storage device. During the shutdown period, the high-temperature phase change energy storage device can release the stored heat energy to continuously and stably generate steam, extend the continuous power generation time of the generator, and ensure the continuity and stability of power generation.

[0018] Secondly, the design of the waste heat recovery system involves using plate heat exchangers to recover the waste heat from the turbine's extraction steam or exhaust steam for use in preparing hot water for heating the plant area or for process applications. This achieves graded recovery and utilization of energy based on its grade, significantly improving the overall energy efficiency of the entire system.

[0019] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the control flow of an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached diagram:

[0022] 1. First fire cabinet 2. Second fire cabinet

[0023] 3. First steam drum 4. Circulating pump

[0024] 5. Waste heat boiler 6. Second steam drum

[0025] 7. Steam header 8. Heat accumulator

[0026] 9. Steam turbine 10. Generator

[0027] 11. Soft water tank 12. Water supply pump

[0028] 13. High-temperature phase change energy storage device 14. Three-way interface

[0029] 15. Plate heat exchanger 16. Circulating water pump

[0030] 17. Electric check valve 18. First electric regulating valve

[0031] 19. Second electric regulating valve; 20. Solar heat exchanger

[0032] 21. Temperature sensor. Detailed Implementation

[0033] Please refer to Figure 1 As shown, it illustrates the specific structure of an embodiment of the present invention.

[0034] In the description of this utility model, it should be noted that the directional terms such as "up", "down", "front", "back", "left", and "right" indicate the orientation and positional relationship based on the accompanying drawings or the orientation or positional relationship shown when wearing and using the device normally. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0035] A power generation system integrating dual steam drum heat storage and waste steam heat recovery includes a first heat exchanger 1, a second heat exchanger 2, a first steam drum 3, a circulating pump 4, a waste heat boiler 5, a second steam drum 6, a steam header 7, a heat accumulator 8, a steam turbine 9, a generator 10, a soft water tank 11, and a feedwater pump 12.

[0036] The output ends of the first heat exchanger 1 and the second heat exchanger 2 are connected to the input end of the first steam drum 3; the first output end of the first steam drum 3 is connected to the first input end of the first heat exchanger 1 and the second heat exchanger 2 respectively; the second output end of the first steam drum 3 is connected to the input end of the steam header 7; the output end of the steam header 7 is connected to the input end of the accumulator 8 through the main pipeline; the output end of the accumulator 8 is connected to the steam turbine 9, and the output end of the steam turbine 9 is connected to the input end of the generator 10; the steam turbine 9 is connected to the soft water tank 11, the soft water tank 11 is connected to the feed water pump 12, and the output end of the feed water pump 12 is connected to the second input ends of the waste heat boiler 5, the first heat exchanger 1, and the second heat exchanger 2 respectively;

[0037] It also includes a high-temperature phase change energy storage device 13 and a waste heat recovery system; a three-way interface 14 is provided on the main pipeline, one of which is connected to the steam inlet of the high-temperature phase change energy storage device 13 through a branch pipeline, and the steam outlet of the high-temperature phase change energy storage device 13 is connected to the other input end of the heat accumulator 8 through another branch pipeline to form a parallel loop; preferably, an electric check valve 17 is also provided at the front end of the three-way interface 14 to prevent steam from flowing back to the waste heat boiler 5; a first electric regulating valve 18 is also provided on the branch pipeline and the steam inlet of the high-temperature phase change energy storage device 13, and a second electric regulating valve 19 is also provided on the other branch pipeline and the steam outlet of the high-temperature phase change energy storage device 13. Through the coordinated action of the electric check valve 17, the electric regulating valve and the control device, the flow direction and distribution of steam in different modes such as power generation, energy storage and energy release can be intelligently controlled according to parameters such as steam pressure and temperature.

[0038] In this embodiment, the phase change material in the high-temperature phase change energy storage device 13 can be a molten salt mixture with a phase change temperature of approximately 280-320°C, which matches the system's 1.6MPa saturated steam temperature. The first and second electric regulating valves 19 can be pneumatic or electric regulating valves, receiving signals from the control system to precisely control the steam flow rate and pressure entering the phase change energy storage device.

[0039] The selection of the plate heat exchanger 15 needs to be determined according to the design heat load. Its primary side design pressure is matched with the steam extraction / exhaust pressure of the steam turbine 9, and the secondary side is used to heat the heating return water (e.g., 55°C) to the required temperature (e.g., 85°C).

[0040] Energy storage mode: When the smelting furnace is running and the power generation load is low, the control device commands the first electric regulating valve 18 to open, and some steam flows into the high temperature phase change energy storage device 13 to store heat, while the second electric regulating valve 19 closes.

[0041] Energy release mode: When the smelting furnace is shut down, the control device commands the first electric regulating valve 18 to close and the second electric regulating valve 19 to open. The phase change energy storage device releases heat and generates stable steam to supplement the main system and maintain the operation of the steam turbine 9.

[0042] Heating mode: When there is a heat demand in the plant area, the control device adjusts the steam extraction valve of the steam turbine 9 and the hot water circulation pump 4 to introduce part of the steam into the plate heat exchanger 15 to heat the heating water and realize combined heat and power.

[0043] The waste heat recovery system includes at least a plate heat exchanger 15 and a circulating water pump 16. The exhaust port of the steam turbine 9 is connected to the primary inlet of the plate heat exchanger 15 through an exhaust pipe. The primary outlet of the plate heat exchanger 15 is connected to a soft water tank 11. The secondary inlet of the plate heat exchanger 15 is connected to the circulating water pump 16. The inlet of the hot water circulating pump 4 is used to connect to the plant's heating return water. The secondary outlet of the plate heat exchanger 15 is used to provide heating or process hot water to the plant.

[0044] Preferably, the exhaust port of the steam turbine generator 10 is connected to a condenser, and the outlet of the condenser is connected to the soft water tank 11.

[0045] Preferably, a water preheating system is further provided between the soft water tank 11 and the water supply pump 12. The water preheating system includes a solar heat exchanger 20. The outlet of the soft water tank 11 is connected to the cold-side inlet of the solar heat exchanger 20, and the cold-side outlet of the solar heat exchanger 20 is connected to the input end of the water supply pump 12, thus achieving coupling with clean energy and further reducing system energy consumption. Preferably, a temperature sensor 21 is provided at the cold-side outlet of the solar heat exchanger 20. Preferably, the water preheating system is also provided with a control device, which is electrically connected to the temperature sensor 21, the electric check valve 17, the first electric regulating valve 18, and the second electric regulating valve 19.

[0046] The working principle of each part of this embodiment is described in detail below:

[0047] Waste heat recovery and steam generation:

[0048] The high-temperature flue gas (approximately 1000-1300℃) generated by the antimony smelting blast furnace passes sequentially through the first firebox 1 and the second firebox 2, heating the water-cooled wall tubes inside. The water is heated into a steam-water mixture inside the firebox, rises, and enters the steam drum of the firebox system for steam-water separation. The separated saturated water is pumped back to the firebox by the circulating pump 4 for continued circulation, while the separated medium-pressure saturated steam (e.g., 1.6MPa) enters the steam header 7. Subsequently, the flue gas (temperature reduced to approximately 800℃) enters the waste heat boiler 5 to continue heating the heating surfaces inside the boiler, generating steam. The generated steam is separated in the steam drum of the waste heat boiler 5 and also enters the steam header 7, realizing the synergistic steam production of the two steam drums.

[0049] Power generation and condensation:

[0050] The mixed steam passes through the main steam pipeline, and after being depressurized and stabilized by the heat accumulator 8 (e.g., from 1.6MPa to 1.0MPa), it enters the steam turbine generator 10 to expand and do work, driving the generator 10 to generate electricity. The exhaust steam after doing work enters the condenser and is condensed into water by the cooling water. The condensate is collected in the soft water tank 11, and then pressurized by the waste heat power generation system to the water pump 12, and then delivered to the waste heat boiler 5, the first fire cabinet 1 and the second fire cabinet 2 respectively, completing the water-steam-water cycle.

[0051] High-temperature phase change energy storage process:

[0052] When the smelting furnace is operating normally but the power generation load is low, causing the pressure in steam header 7 to exceed the set value,

[0053] The control device issues a command to open the first electric regulating valve 18, and at the same time moderately closes the pipeline leading to the heat storage device 8 (or relies on pressure difference), so that a portion of the excess medium-pressure saturated steam enters the high-temperature phase change energy storage device 13 through the branch pipeline. The steam releases heat in the high-temperature phase change energy storage device 13, heating and melting the phase change material (such as molten salt) therein, and the thermal energy is thus stored in a high density in the form of latent heat.

[0054] Energy release (discharge) mode:

[0055] When the smelting furnace is shut down for ash removal and the steam source is interrupted, the pressure in the steam header 7 begins to drop. The control device closes the first electric regulating valve 18 and opens the second electric regulating valve 19 to absorb the large amount of latent heat released when the phase change material solidifies, and quickly vaporizes to generate steam at a stable pressure. This steam is then supplied to the main steam pipeline through the second electric regulating valve 19 or directly enters the heat accumulator 8 to continue driving the turbine generator 10 to generate electricity, greatly extending the power generation time.

[0056] Next, a portion of the steam with higher pressure and temperature that has done some work is extracted from the steam extraction port of the steam turbine generator 10. The selected steam enters the primary side (high temperature side) of the plate heat exchanger 15. The low temperature return water of the plant heating system enters the secondary side (low temperature side) of the plate heat exchanger 15 under the drive of the hot water circulation pump 4.

[0057] This allows the steam on the primary side to condense and release heat within the plate heat exchanger 15, transferring the remaining heat to the circulating water on the secondary side. The heated water (e.g., from 55°C to 85°C) is then transported to the plant area for winter heating or year-round process heating. The condensate from the primary side is recycled to the condenser or soft water tank 11 and re-enters the circulation.

[0058] The key design feature of this invention is that it connects a high-temperature phase change energy storage device in parallel between the steam header and the accumulator. In this way, when the smelting furnace (antimony smelting blast furnace) is running normally, excess steam can be stored in the phase change energy storage device. During the shutdown period, the high-temperature phase change energy storage device can release the stored heat energy to continuously and stably generate steam, extend the continuous power generation time of the generator, and ensure the continuity and stability of power generation.

[0059] Secondly, the design of the waste heat recovery system involves using plate heat exchangers to recover the waste heat from the turbine's extraction steam or exhaust steam for use in preparing hot water for heating the plant area or for process applications. This achieves graded recovery and utilization of energy based on its grade, significantly improving the overall energy efficiency of the entire system.

[0060] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A power generation system integrating dual-drum thermal storage and waste heat recovery, comprising a first heat exchanger, a second heat exchanger, a first steam drum, a circulating pump, a waste heat boiler, a second steam drum, a steam header, a heat accumulator, a steam turbine, a generator, a soft water tank, and a feedwater pump; the output ends of the first heat exchanger and the second heat exchanger are connected to the input end of the first steam drum; the first output end of the first steam drum is respectively connected to the first input end of the first heat exchanger and the second heat exchanger; the second output end of the first steam drum is connected to the input end of the steam header; the output end of the steam header is connected to the input end of the heat accumulator via a main pipeline; the output end of the heat accumulator is connected to the steam turbine, and the output end of the steam turbine is connected to the input end of the generator; the steam turbine is connected to the soft water tank, the soft water tank is connected to the feedwater pump, and the output end of the feedwater pump is respectively connected to the second input ends of the waste heat boiler, the first heat exchanger, and the second heat exchanger; characterized in that: It also includes a high-temperature phase change energy storage device and a waste heat recovery system; the main pipeline is equipped with a three-way interface, one of which is connected to the steam inlet of the high-temperature phase change energy storage device through a branch pipeline, and the steam outlet of the high-temperature phase change energy storage device is connected to the other input end of the heat accumulator through another branch pipeline to form a parallel loop. The waste heat recovery system includes at least a plate heat exchanger and a circulating water pump. The exhaust port of the steam turbine is connected to the primary inlet of the plate heat exchanger via an exhaust pipe, and the primary outlet of the plate heat exchanger is connected to a soft water tank. The secondary inlet of the plate heat exchanger is connected to the circulating water pump. The inlet of the circulating water pump is used to connect to the plant's heating return water, and the secondary outlet of the plate heat exchanger is used to provide heating or process hot water to the plant.

2. The integrated power generation system for dual-steam drum thermal storage and waste steam heat recovery according to claim 1, characterized in that: The front end of the three-way interface is also equipped with an electric check valve to prevent steam from flowing back to the waste heat boiler; the branch pipe is also equipped with a first electric regulating valve at the steam inlet of the high-temperature phase change energy storage device, and the other branch pipe is also equipped with a second electric regulating valve at the steam outlet of the high-temperature phase change energy storage device.

3. The integrated power generation system for dual-steam drum thermal storage and waste steam heat recovery according to claim 1, characterized in that: The turbine's exhaust port is connected to a condenser, and the condenser's outlet is connected to the soft water tank.

4. The integrated power generation system for dual-steam drum thermal storage and waste steam heat recovery according to claim 2, characterized in that: A water preheating system is also provided between the soft water tank and the water supply pump. The water preheating system includes a solar heat exchanger. The outlet of the soft water tank is connected to the cold side inlet of the solar heat exchanger, and the cold side outlet of the solar heat exchanger is connected to the input end of the water supply pump.

5. The integrated power generation system for dual-steam drum thermal storage and waste heat recovery according to claim 4, characterized in that: A temperature sensor is installed at the cold side outlet of the solar heat exchanger.

6. The integrated power generation system for dual-steam drum thermal storage and waste steam heat recovery according to claim 4, characterized in that: The water preheating system is also equipped with a control device, which is electrically connected to a temperature sensor, an electric check valve, a first electric regulating valve, and a second electric regulating valve.

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