Energy storage steam system suitable for intermittent waste heat utilization

Abstract

The utility model discloses an energy storage steam system suitable for intermittent waste heat utilization, which comprises a main body flue, a fused salt heat exchange module and a water heat exchange module are arranged in the main body flue, the fused salt heat exchange module comprises a salt heat exchanger, the salt heat exchanger is arranged in the main body flue, and the water heat exchange module is arranged in the main body flue. The inlet end and the outlet section of the salt heat exchanger communicate with a cold salt tank and a hot salt tank through conveying pipelines correspondingly, the water heat exchange module comprises a water quality heat exchanger, the water quality heat exchanger is arranged in a main flue, and the inlet end and the outlet section of the water quality heat exchanger are arranged in a condensation water tank and a deaerator through conveying pipelines correspondingly; the output end of the deaerator communicates with the fused salt-steam generating device, and the cold salt tank and the hot salt tank communicate with the fused salt-steam generating device. Fused salt is used as a high-temperature heat transfer and storage medium, water is used as a heat transfer and storage medium of a low-temperature area, waste heat of intermittent flue gas or process gas is recycled, high-parameter steam is generated through recycled heat, and the requirements for external driving, heat supply, power generation or heat supply and the like are met.

Description

Technical Field

[0001] This utility model relates to an energy storage steam system suitable for intermittent waste heat utilization, which is its main application scenario in the field of industrial energy conservation. It is particularly suitable for the utilization of waste heat from discontinuous (or periodic) flue gas or process gas in metal smelting, silicon material purification, etc. The steam generated by this system can be used for driving, power generation, heating, or heating. Background Technology

[0002] During converter steelmaking, the reaction between oxygen and reducing agent generates a large amount of heat. This heat serves two purposes: it sustains the normal progress of the reaction, while a large amount of waste heat is discharged with the converter flue gas.

[0003] During electric arc furnace steelmaking, a large amount of heat is required to melt scrap steel, so a large amount of electrical energy input is usually needed to meet the process requirements, and a large amount of waste heat is also generated and discharged with the converter flue gas.

[0004] Therefore, waste heat recovery is an important way to improve the energy utilization efficiency of converter processes. Intermittent flue gas or process gas can be used in many other processes, which will not be listed here.

[0005] The most common way to utilize intermittent waste heat is through water-cooled wall structures for waste heat recovery. This waste heat recovery device generates saturated steam with specific parameters for power generation, heating, or thermal power generation. This method has advantages such as system simplicity and low investment cost, but it also has the following two problems:

[0006] First, the heat dissipation process of the above-mentioned process is intermittent. Due to its weak heat storage capacity, the waste heat recovery system using water as the working fluid is difficult to adapt to the characteristics of periodic fluctuations. The steam parameters generated by the system are usually unstable, which poses a challenge to the subsequent power generation or heat consumption process.

[0007] Secondly, the waste heat recovery process using water as the working fluid typically produces low saturated steam parameters. When used for power generation, these low steam parameters limit the system's energy utilization efficiency, thus imposing constraints on improving the energy efficiency of the waste heat process. Utility Model Content

[0008] To address the aforementioned technical problems, this invention presents an energy storage steam system suitable for the utilization of intermittent waste heat. This system utilizes molten salt as a high-temperature heat transfer and storage medium, and water as a low-temperature heat transfer and storage medium, to recover waste heat from intermittent flue gas or process gas. The recovered heat is then used to generate high-parameter steam, meeting the needs for external drive, heating, power generation, or heating supply.

[0009] The present invention adopts the following technical solution:

[0010] A storage steam system suitable for intermittent waste heat utilization includes an inlet flue, a main flue, and an outlet flue. The main flue houses a molten salt heat exchange module and a water heat exchange module. The molten salt heat exchange module includes a salt heat exchanger located within the main flue. The inlet and outlet of the salt heat exchanger are connected to a cold salt tank and a hot salt tank, respectively, via pipelines. The water heat exchange module includes a water heat exchanger located within the main flue. The inlet and outlet of the water heat exchanger are connected to a condensate tank and a deaerator, respectively, via pipelines. The deaerator output is connected to a molten salt-steam generator. The cold salt tank and the hot salt tank are connected to the molten salt-steam generator.

[0011] Preferably, the main flue is arranged vertically, with the molten salt heat exchange modules and water heat exchange modules arranged from low to high along the height direction. This facilitates the complete drainage of the molten salt medium inside the system when it is shut down, eliminating the risk of frozen salt and pipe blockage, and improving the safety and lifespan of the system.

[0012] Preferably, a cold salt pump is installed on the delivery pipeline between the cold salt tank and the salt heat exchanger.

[0013] Preferably, a hot salt pump is installed on the conveying pipeline between the hot salt tank and the molten salt-steam generator.

[0014] Preferably, a condensate pump is installed on the delivery pipeline between the condensate tank and the water heat exchanger.

[0015] Preferably, a water supply pump is installed on the pipeline between the deaerator and the molten salt-steam generator.

[0016] The beneficial effects of this utility model are: (1) It can be applied to the waste heat recovery process of discontinuous (or periodic) flue gas or process gas; (2) Molten salt and water are used as heat transfer and heat storage media, and energy is stored in stages according to the quality, thereby improving the energy utilization efficiency of the whole system; (3) During the heat storage process, the flow rate of molten salt and water is flexibly adjusted according to the waste heat parameters (flow rate, temperature, etc.) to match the periodic emission characteristics of flue gas or process gas; (4) The preferred arrangement of this system is vertical, which facilitates the salt removal and gas release of molten salt equipment and system, thereby improving the safety and lifespan of the system; (5) Through the heat storage and heat release process of molten salt and water dual media, the energy recovery and waste heat utilization are decoupled, and the output thermal parameters of the system can be kept stable or flexibly adjusted according to the needs; (6) The high temperature molten salt generated by the heat improves the output steam parameters of the system, which can improve the power generation efficiency of the system when used for power generation, and can adapt to more heat use scenarios when used for heating. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] In the diagram: 1. Inlet flue, 2. Main flue, 3. Exhaust flue, 4. Cold brine tank, 5. Cold brine pump, 6. Salt heat exchanger, 7. Hot brine tank, 8. Condensate tank, 9. Condensate pump, 10. Water heat exchanger, 11. Deaerator, 12. Feed water pump, 13. Hot brine pump, 14. Molten salt-steam generator. Detailed Implementation

[0019] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings:

[0020] Example: Figure 1 As shown, an energy storage steam system suitable for intermittent waste heat utilization includes an inlet flue 1, a main flue 2, an outlet flue 3, a cold brine tank 4, a cold brine pump 5, a brine heat exchanger 6, a hot brine tank 7, a condensate tank 8, a condensate pump 9, a water heat exchanger 10, a deaerator 11, a feedwater pump 12, a hot brine pump 13, and a molten salt-steam generator 14.

[0021] The main flue contains molten salt heat exchange modules and water heat exchange modules. The molten salt heat exchange module includes a salt heat exchanger, which is located in the main flue. The inlet and outlet of the salt heat exchanger are connected to a cold salt tank and a hot salt tank, respectively, via pipelines. The water heat exchange module includes a water heat exchanger, which is located in the main flue. The inlet and outlet of the water heat exchanger are connected to a condensate tank and a deaerator, respectively, via pipelines. The output of the deaerator is connected to a molten salt-steam generator. The cold salt tank and the hot salt tank are connected to the molten salt-steam generator.

[0022] Condensate is typically generated from externally supplied steam after power generation or heat utilization. If the condensate cannot be recovered or can only be partially recovered, the system requires a makeup water device of appropriate capacity. High-temperature flue gas or process gas sequentially passes through the inlet flue, main flue, and exhaust flue; and in the main flue, it transfers heat to molten salt and water. The cooled flue gas or process gas flows out of the system through the exhaust flue.

[0023] The main flue is vertically arranged, with molten salt heat exchange modules and water heat exchange modules arranged from low to high along the height direction. This facilitates the complete drainage of the molten salt medium inside the system when it is shut down, eliminating the risk of frozen salt and pipe blockage, and improving the safety and lifespan of the system.

[0024] When this utility model is used, the heat storage process is as follows:

[0025] High-temperature flue gas or process gas enters the system through the inlet flue 1, where it transfers heat to the molten salt and water medium within the main flue 2, and then leaves the system through the outlet flue 3.

[0026] The cold salt pump 5 draws the lower-temperature molten salt from the cold salt tank 4 and enters the salt heat exchanger 6, where it absorbs the heat from the high-temperature flue gas or process gas and returns to the hot salt tank 7 as high-temperature molten salt, storing the heat from the high-temperature section in the molten salt.

[0027] Condensate pump 9 draws cooler water from condensate tank 8 and enters water heat exchanger 10 to absorb heat from low-temperature flue gas or process gas. After the water temperature rises, it enters deaerator 11 to store the low-temperature heat in hot water.

[0028] Based on the flow rate and temperature parameters of the flue gas or process gas, adjust the flow rate of the medium in the salt heat exchanger 6 and the water heat exchanger 10 to keep the temperature of the medium at the outlet of the salt heat exchanger 6 and the outlet of the water heat exchanger 10 basically stable.

[0029] Exothermic process:

[0030] The hot salt pump 13 draws high-temperature molten salt from the hot salt tank 7 and enters the molten salt-steam generator 14, where it transfers heat to the water medium. After the molten salt temperature drops, it returns to the cold salt tank 4.

[0031] The working fluid originates from the deaerator 11 and enters the molten salt-steam generator 14 after being driven by the feed water pump 12. In the generator, it absorbs the heat released by the molten salt to complete the heating, evaporation and superheating process, and becomes steam with the required parameters to be sent out of the system.

[0032] This energy storage steam system, suitable for intermittent waste heat utilization, utilizes the different properties of molten salt and water to achieve cascaded energy storage and utilization. It also decouples the heat storage and utilization processes, transforming unstable waste heat input into stable and adjustable steam output. The vertical structural design allows for complete system venting during shutdowns, eliminating the risks of freezing and pipe blockage in the molten salt equipment and system. Compared to existing water-based solutions, this solution improves the parameters and quality of the thermal storage system. During heat release, it enhances the system's output steam parameters, resulting in higher power generation efficiency and stronger heating adaptability. It represents an upgraded technology for intermittent waste heat utilization. This system is an important way to improve energy efficiency and reduce carbon emission intensity.

[0033] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A steam storage system suitable for intermittent waste heat utilization, comprising an inlet flue, a main flue, and an outlet flue, characterized in that, The main flue is equipped with a molten salt heat exchange module and a water heat exchange module. The molten salt heat exchange module includes a salt heat exchanger, which is located in the main flue. The inlet and outlet of the salt heat exchanger are connected to a cold salt tank and a hot salt tank, respectively, via pipelines. The water heat exchange module includes a water heat exchanger, which is located in the main flue. The inlet and outlet of the water heat exchanger are connected to a condensate tank and a deaerator, respectively, via pipelines. The output of the deaerator is connected to a molten salt-steam generator. The cold salt tank and the hot salt tank are connected to the molten salt-steam generator.

2. The energy storage steam system for intermittent waste heat utilization according to claim 1, characterized in that, The main flue is arranged vertically, and the molten salt heat exchange module and the water heat exchange module are arranged from low to high along the height direction.

3. The energy storage steam system for intermittent waste heat utilization according to claim 1, characterized in that, A cold salt pump is installed on the pipeline between the cold salt tank and the salt heat exchanger.

4. The energy storage steam system for intermittent waste heat utilization according to claim 1, characterized in that, A hot salt pump is installed on the pipeline connecting the hot salt tank and the molten salt-steam generator.

5. A steam storage system for intermittent waste heat utilization according to claim 1, characterized in that, A condensate pump is installed on the pipeline between the condensate tank and the water heat exchanger.

6. A steam storage system for intermittent waste heat utilization according to claim 1, characterized in that, A water pump is installed on the pipeline between the deaerator and the molten salt-steam generator.

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