Steam production system for recycling waste heat of low-temperature dust-containing high-acid flue gas and production method of steam production system

Abstract

The invention relates to the technical field of waste heat recovery, in particular to a steam production system and method for recovering waste heat of low-temperature dust-containing high-acid flue gas, and the steam production system comprises a flue gas loop, a saturated water loop, a saturated steam loop and an electric control loop; the flue gas loop is connected with the heat source side of the heat pipe exchanger; the saturated water loop is connected with a working medium side of the heat pipe heat exchanger, is connected with an inlet of the flash tank and a liquid outlet of the flash tank, and is connected with other saturated water utilization scenes through a circulating water replenishing tank and a water tank pressurizing valve; through the synergistic effect of the heat pipe heat exchanger, flash evaporation, mechanical vapor compression (MVR) and electric control adjustment, the problems of equipment corrosion, abrasion and low waste heat utilization efficiency in the prior art are solved, comprehensive recycling of low-temperature dust-containing high-acid flue gas waste heat is achieved, and stable low-pressure saturated vapor is produced.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery, and in particular to a steam production system for recovering waste heat of low-temperature dusty and highly acidic flue gas and a production method thereof. Background Art

[0002] In the process of metal smelting and other industrial production, low-temperature dusty and highly acidic flue gas with a temperature below 150°C is common, and its dust content can be as high as 2000mg / Nm 3 , and contains SO 2 Due to the low temperature, high dust and high acidity of flue gas, traditional waste heat recovery equipment is susceptible to corrosion and wear during operation, resulting in short equipment life and low heat exchange efficiency. In addition, in the existing process, the waste heat of flue gas is often discharged without effective recovery, which not only causes energy waste, but also increases the load of subsequent dust removal and desulfurization. Therefore, it is of great economic and environmental significance to develop a waste heat recovery system that can operate stably under low temperature, high dust and high acidity conditions and realize steam production.

[0003] In the existing technology, some schemes attempt to produce hot water through conventional alloy heat exchangers and generate steam in combination with flash evaporation technology, but it is difficult to operate stably for a long time due to acid dew point corrosion and wear problems; another scheme proposes to use fluoroplastic tube heat exchangers, but their wear resistance is insufficient and it is difficult to cope with high dust flue gas conditions.

[0004] In view of the above problems, the present invention proposes a steam production system and method for recovering waste heat from low-temperature, dusty and high-acid flue gas, so as to achieve effective recovery of waste heat from low-temperature, dusty and high-acid flue gas and stability of steam production. Summary of the invention

[0005] The object of the present invention is to provide a steam production system for recovering waste heat from low-temperature, dusty and highly acidic flue gas and a control method thereof, which solves the problems of equipment corrosion, wear and low waste heat utilization efficiency in the prior art through the synergistic effect of a heat pipe heat exchanger, flash evaporation, mechanical vapor compression (MVR) and electronic control regulation, realizes the comprehensive recovery and utilization of waste heat from low-temperature, dusty and highly acidic flue gas, and produces stable low-pressure saturated steam.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] A steam production system for recovering waste heat of low-temperature dusty and highly acidic flue gas, comprising: a flue gas loop connected to the heat source side of a heat pipe heat exchanger, for inputting low-temperature dusty and highly acidic flue gas into the heat pipe heat exchanger for heat exchange;

[0008] The saturated water circuit is connected to the working medium side of the heat pipe heat exchanger, and includes a circulating water supply tank, a water tank pressurizing valve, an inlet electrically controlled three-way valve, a water supply electrically controlled four-way valve, an outlet electrically controlled three-way valve, an inlet temperature sensor, and an outlet temperature sensor; the saturated water circuit forms a closed preheating circuit through the inlet electrically controlled three-way valve and the water supply electrically controlled four-way valve, which is used for preheating the working medium when the system is started;

[0009] The inlet of the flash tank is connected to the outlet of the working fluid side of the heat pipe heat exchanger, and the liquid outlet is connected to the circulating water tank and the external secondary utilization scene through the outlet electric-controlled three-way valve;

[0010] A saturated steam circuit, comprising a steam accumulator and a mechanical steam recompressor, wherein the steam accumulator is connected to the steam outlet of the flash tank for stabilizing the steam pressure, and the mechanical steam recompressor is used for pressurizing the steam for output;

[0011] The electric control circuit includes electric control elements, which are used to control the valve openings of the inlet electric control three-way valve, the water replenishment electric control four-way valve and the outlet electric control three-way valve according to the feedback signals of the inlet temperature sensor and the outlet temperature sensor, so as to realize the working fluid temperature control, the water replenishment ratio adjustment and the secondary utilization distribution of the scarce water.

[0012] Furthermore, the steam outlet of the flash tank is connected to the steam accumulator to balance the steam fluctuation caused by the flue gas fluctuation, so that the produced steam can stably enter the mechanical steam recompressor and produce corresponding saturated steam according to requirements.

[0013] Furthermore, the heat pipe heat exchanger is an eccentric radial heat pipe heat exchanger. The heat pipe elements exchange heat individually and are independent of each other. If a single heat pipe is damaged, it is easy to replace, so as to cope with problems such as severe corrosion and high friction under low temperature, high dust and acidic flue gas conditions, and effectively improve the system efficiency.

[0014] Furthermore, the heat pipe heat exchanger in the saturated water circuit, the inlet electrically controlled three-way valve, and the water supply electrically controlled four-way valve form a closed preheating circuit, so that the saturated water can reach the required working condition of the flash tank as soon as possible when the system is started.

[0015] On the other hand, the present invention provides a steam production method based on the above system, comprising the following steps:

[0016] Flue gas preheating stage: low-temperature, dusty and high-acid flue gas enters the heat source side of the heat pipe heat exchanger to release heat, and enters the subsequent desulfurization and dust removal process after cooling;

[0017] System start preheating: The inlet electric control three-way valve and the water supply electric control four-way valve are controlled by the electric control circuit to make the circulating water circulate in the closed preheating circuit until the inlet temperature sensor detects that the circulating water temperature reaches the set threshold;

[0018] Flash steam production: After preheating is completed, the electronic control circuit switches the valve state to allow saturated water to enter the flash tank for flash evaporation to generate low-pressure saturated steam;

[0019] Steam stabilization and pressurization: The steam after flash evaporation is stabilized by the steam accumulator and then enters the mechanical steam compressor for pressurization, outputting steam at the target pressure;

[0020] Utilization of waste water waste heat: The waste water after flash evaporation is distributed in proportion through the outlet electronically controlled three-way valve. One part is used as high-temperature make-up water and mixed with the low-temperature water in the circulating make-up water tank and then returned to the heat pipe heat exchanger, and the other part is transported to the secondary utilization scene for waste heat recovery;

[0021] Dynamic adjustment: The outlet temperature sensor is used to monitor the feed water temperature in real time, and the high and low temperature feed water mixing ratio of the feed water electric control four-way valve is adjusted to ensure the stability of the working fluid temperature at the inlet of the heat pipe heat exchanger.

[0022] Furthermore, the electronic control circuit is controlled by the following logic: when the inlet temperature sensor detects that the circulating water temperature is lower than the set threshold, the closed preheating circuit circulation is maintained; when the temperature reaches the threshold, the inlet electronically controlled three-way valve and the water supply electronically controlled four-way valve are switched to the main circuit to allow saturated water to enter the flash tank; according to the feedback from the outlet temperature sensor, the high and low temperature water supply ratio of the water supply electronically controlled four-way valve is dynamically adjusted to control the mixed water temperature within the range of ±2°C.

[0023] Furthermore, a flash tank and a mechanical steam recompressor are provided to produce low-pressure saturated steam through flash technology, and a mechanical steam recompressor is used to make the steam produced by the system meet the requirements.

[0024] Furthermore, after flash evaporation, part of the water depletion is used as high-temperature make-up water in different proportions, and the other part is used as a low-grade heat source for secondary utilization, which effectively improves the utilization rate of waste heat from the water depletion while ensuring that the make-up water meets the system requirements.

[0025] Furthermore, the outlet temperature sensor and the water supply electric control four-way valve control the flow distribution of high-temperature and low-temperature water supply through the electronic control components to ensure the stability of the water supply temperature.

[0026] Furthermore, the inlet temperature sensor, the inlet electric-controlled three-way valve, and the water supply electric-controlled four-way valve are passed into the flash tank through the electronic control components after the working fluid in the preheating circuit reaches the target temperature.

[0027] Beneficial effects of the present invention:

[0028] The system of the present invention adopts an eccentric radial heat pipe heat exchanger as the core heat exchange unit based on the phase change heat transfer principle of the heat pipe. The evaporation section of the heat pipe contacts the dusty high-acid flue gas. The working fluid absorbs the waste heat of the flue gas and then vaporizes. It diffuses to the condensation section through the internal pressure difference and releases latent heat, heating the saturated water to the temperature required for flash evaporation. The efficient heat transfer characteristics of the heat pipe are derived from the rapid cycle of the working fluid phase change process. Its equivalent thermal conductivity is significantly higher than that of traditional metal materials, and the radial eccentric layout optimizes the flue gas flow path and reduces the deposition of dust on the pipe wall. The heat pipe adopts corrosion-resistant alloy and surface coating technology, combined with modular design, and a single heat pipe can be replaced independently to avoid the overall heat exchange efficiency from being reduced due to local corrosion or wear. By adjusting the spacing and inclination of the heat pipes, the dust is caused to slide down by gravity to maintain the cleanliness of the heat exchange surface. It not only improves the waste heat recovery efficiency, but also solves the corrosion problem of high-acid flue gas on metal materials, ensuring the long-term stable operation of the system under harsh working conditions.

[0029] The system of the present invention realizes the stable output of steam parameters through the synergistic effect of the flash tank and the steam accumulator. The flash tank converts high-temperature saturated water into steam by the principle of isenthalpic flash evaporation, while the steam accumulator buffers the steam pressure changes caused by flue gas fluctuations through a high heat capacity heat storage medium. The mechanical steam recompressor (MVR) dynamically adjusts the steam pressure according to downstream demand to form a closed-loop control. The flash tank ensures that the steam production matches the waste heat through real-time feedback adjustment of the liquid level and pressure. The heat storage medium inside the steam accumulator absorbs or releases heat when the flue gas load fluctuates, suppressing pressure fluctuations. The MVR adjusts the compression ratio through a variable frequency drive to achieve precise control of the steam pressure. It effectively responds to the dynamic changes of flue gas flow and temperature, ensures the continuity and stability of steam supply, and meets the stringent requirements of industrial production.

[0030] The system of the present invention reduces the risk of corrosion and improves the utilization rate of waste heat through graded reuse of scarce water and dynamic mixing control. The scarce water generated after flash evaporation is divided into high-temperature reuse water and low-grade heat source through an electronically controlled valve. The former is mixed with low-temperature make-up water and returned to the heat exchanger, and the latter is used for secondary waste heat recovery. Real-time regulation of the mixed water temperature can prevent the inlet temperature of the heat exchanger from being lower than the acid dew point, thereby inhibiting the condensation corrosion of acidic components such as sulfuric acid. At the same time, the high-temperature reuse of scarce water reduces the enrichment of corrosive ions in the circulating water and delays equipment degradation. The secondary utilized scarce water is used to generate electricity or preheat the process medium through a low-boiling-point working fluid to achieve the cascade utilization of waste heat. The electronic control system dynamically optimizes the mixing ratio and diversion strategy based on sensor data to achieve a balance between corrosion prevention and energy efficiency improvement.

[0031] The system of the present invention integrates temperature, pressure, flow sensors and electronically controlled valves to construct a dynamic optimization model to adjust the working fluid distribution, flash pressure and MVR operating parameters in real time. During the startup phase, the electronic control system quickly increases the working fluid temperature through the preheating circuit to avoid the risk of corrosion during cold operation. During operation, the system predicts the steam production based on the waste heat of the flue gas, dynamically adjusts the flash tank pressure and the MVR compression ratio to ensure efficient operation under partial load. Through the intelligent diversion and secondary utilization of scarce water, the system significantly reduces the amount of external water and energy consumption while ensuring steam production. This control strategy not only improves the adaptive ability of the system, but also reduces the unit steam production cost through the deep utilization of waste heat.

[0032] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0034] Figure 1 This is a schematic diagram of the steam production system structure based on recovering the waste heat of low-temperature dusty and high-acid flue gas; in the figure: 1. heat pipe heat exchanger, 2. inlet electric-controlled three-way valve, 3. water supply electric-controlled four-way valve, 4. inlet temperature sensor, 5. water tank pressurizing valve, 6. electronic control components, 7. outlet temperature sensor, 8. flash tank, 9. circulating water supply tank, 10. outlet electric-controlled three-way valve, 11. steam accumulator, 12. mechanical steam recompressor, 13. external secondary utilization scenario;

[0035] Figure 2 It is a schematic diagram of steam production under different flue gas flow rates;

[0036] Figure 3 Schematic diagram of power generation under different flue gas flow rates and secondary utilization scenarios. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] The steam production system for recovering waste heat from low-temperature dusty and highly acidic flue gas described in this embodiment is as follows: Figure 1 As shown, it includes a flue gas circuit, a saturated water circuit, a saturated steam circuit, and an electric control circuit; the flue gas circuit is connected to the heat source side of the heat pipe heat exchanger 1; the saturated water circuit is connected to the working medium side of the heat pipe heat exchanger 1, and is also connected to the inlet of the flash tank 8 and the liquid outlet of the flash tank 8. The saturated water circuit is connected to the external secondary utilization scene 13 by the circulating water supply tank 9 and the water tank pressurizing valve 5. The saturated water circuit is provided with an inlet electric-controlled three-way valve 2, an outlet electric-controlled three-way valve 10, a water supply electric-controlled four-way valve 3, an inlet temperature sensor 4 and an outlet temperature sensor 7. The saturated steam circuit is connected to the steam outlet of the flash tank 8, including a steam accumulator 11 and a mechanical steam recompressor 12. The electric control circuit is respectively connected to the electric control element 6, the inlet electric-controlled three-way valve 2, the outlet electric-controlled three-way valve 10, the water supply electric-controlled four-way valve 3, the inlet temperature sensor 4 and the outlet temperature sensor 7.

[0040] In this embodiment, when the flue gas temperature fluctuates, the quality of the flue gas produced by the flash tank will also fluctuate. The steam accumulator can effectively maintain the steam pressure at the inlet of the mechanical steam recompressor, thereby improving the steam production efficiency of the system.

[0041] In this embodiment, when the external secondary utilization scenario is used as other heat source utilization scenarios within the factory, saturated water at 0.1MPa and about 100°C is widely used in the smelting industry, including: slurry heating / thickener hot water supply, flue gas washing water preheating, furnace cooling water preheating, wet electrolytic cell hot water supply, living area heating and water supply, etc.

[0042] Example 2

[0043] The present invention also discloses a control method for a steam production system for recovering waste heat of low-temperature, dusty and high-acid flue gas. During the operation of the system, the flue gas enters the heat pipe heat exchanger 1 through the flue gas loop. The working medium in the saturated water loop is first preheated in a closed preheating loop composed of the heat pipe heat exchanger 1, the inlet electrically controlled three-way valve 2, and the water replenishment electrically controlled four-way valve 3. The electronic control element controls the disconnection of the closed loop and access to the main loop according to the temperature signal collected by the inlet temperature sensor 4, and enters the flash tank 8 for flash evaporation. The saturated steam produced after flash evaporation enters the saturated steam loop, and after the pressure and temperature are stabilized in the steam accumulator 11, the stable steam is output and enters the mechanical steam recompressor 12. After pressurization, steam under the required pressure is output. The saturated depleted water after flash evaporation returns to the saturated water loop, and the electronic control element controls the disconnection of the closed loop and access to the main loop according to the temperature signal collected by the inlet temperature sensor 4. The depleted water enters the flash tank 8 for flash evaporation. The saturated steam produced after flash evaporation enters the saturated steam loop, and after the pressure and temperature are stabilized in the steam accumulator 11, the stable steam is output and enters the mechanical steam recompressor 12. After pressurization, steam under the required pressure is output. The saturated depleted water after flash evaporation returns to the saturated water loop, and the electronic control element controls the output according to the output. The temperature signal collected by the temperature sensor 7 controls the flow distribution ratio of the outlet electric-controlled three-way valve 10, and controls the direct return and secondary utilization ratio of the scarce water; at the same time, the water replenishment electric-controlled four-way valve controls the mixing ratio of the low-temperature circulating water and the high-temperature scarce water, so as to ensure that the working medium temperature at the inlet of the heat pipe heat exchanger 1 meets the production requirements. The outlet electric-controlled three-way valve 10 distributes the high-temperature scarce water for secondary utilization into the external secondary utilization scene 13. The external secondary utilization scene can be used for organic Rankine cycle, slurry heating / thickener hot water supply, flue gas washing water preheating, furnace cooling water preheating, wet electrolyzer hot water supply and living area heating and water supply, etc. After the secondary waste heat is utilized, the working medium circulation water tank 9 is replenished, and after being pressurized by the water tank pressurizing valve 5, it is mixed with the high-temperature scarce water through the water replenishment electric-controlled four-way valve 3.

[0044] In this embodiment, the flue gas inlet temperature is 130°C and the outlet temperature is 75°C. The circulating water is heated from 35°C to 120°C through a heat pipe heat exchanger (efficiency 90%) and enters a flash tank (saturated pressure 0.1MPa) to generate steam. The depleted water is diverted through the outlet electric three-way valve, part of which is returned to the circulating water tank and part of which is used for organic Rankine cycle power generation (efficiency 10%). Three flue gas flow rates (100,000kg / h, 166,667kg / h, 200,000kg / h) and three depleted water secondary utilization distribution ratios (100% return water, 50% return water + 50% secondary utilization, 30% return water + 70% secondary utilization) are designed, totaling nine working conditions. The 9 working conditions are marked in order: 1A (100,000kg / h, 100% return water), 1B (100,000kg / h, 50% return water + 50% secondary utilization), 1C (100,000kg / h, 30% return water + 70% secondary utilization), 2A (166,667kg / h, 100% return water), 2B (166,667kg / h, 50% return water + 50% secondary utilization), 2C (166,667kg / h, 30% return water + 70% secondary utilization), 3A (200,000kg / h, 100% return water), 3B (200,000kg / h, 50% return water + 50% secondary utilization), 3A (200,000kg / h, 30% return water + 70% secondary utilization).

[0045] The steam production of the system under different flue gas flow rates is as follows Figure 2 As shown in the figure, at a flue gas flow rate of 100,000 kg / h, the steam production is 165 kg / h; at a flow rate of 166,667 kg / h, the steam production is 275 kg / h; at a flow rate of 200,000 kg / h, the steam production is 330 kg / h. When the secondary utilization is organic Rankine cycle power generation, the power generation power at different flue gas flow rates is as follows Figure 3 As shown in the figure, at a flue gas flow rate of 100,000kg / h, the power generation is 0kW, 2.11kW, and 2.95kW respectively; at a flow rate of 166,667kg / h, the steam output is 275kg / h, and the power generation is 0kW, 3.52kW, and 4.92kW respectively; at a flow rate of 200,000kg / h, the steam output is 330kg / h, and the power generation is 0kW, 4.22kW, and 5.90kW respectively. The above operating conditions show that the steam output is proportional to the flue gas flow rate, and the power generation increases with the increase of the secondary utilization ratio and flow rate. The system can operate stably under different operating conditions, and the secondary utilization strategy can be flexibly adjusted to optimize the economy.

[0046] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A steam production system for recovering waste heat from low-temperature dusty and highly acidic flue gas, characterized in that: include: A flue gas loop connected to the heat source side of the heat pipe heat exchanger (1) and used to input low-temperature dusty and high-acid flue gas into the heat pipe heat exchanger (1) for heat exchange; A saturated water circuit is connected to the working medium side of the heat pipe heat exchanger (1), comprising a circulating water supply tank (9), a water tank pressurizing valve (5), an inlet electrically controlled three-way valve (2), a water supply electrically controlled four-way valve (3), an outlet electrically controlled three-way valve (10), an inlet temperature sensor (4) and an outlet temperature sensor (7); the saturated water circuit forms a closed preheating circuit through the inlet electrically controlled three-way valve (2) and the water supply electrically controlled four-way valve (3), and is used for preheating the working medium when the system is started; A flash tank (8), the inlet of which is connected to the outlet of the working medium side of the heat pipe heat exchanger (1), and the liquid outlet is respectively connected to the circulating water supply tank (9) and the external secondary utilization scene (13) through the outlet electric-controlled three-way valve (10); A saturated steam circuit comprises a steam accumulator (11) and a mechanical steam recompressor (12), wherein the steam accumulator (11) is connected to the steam outlet of the flash tank (8) for stabilizing the steam pressure, and the mechanical steam recompressor (12) is used for pressurizing the steam for output; The electric control circuit comprises an electric control element (6) for controlling the valve opening of an inlet electric control three-way valve (2), a water replenishment electric control four-way valve (3) and an outlet electric control three-way valve (10) according to feedback signals from an inlet temperature sensor (4) and an outlet temperature sensor (7), so as to achieve working fluid temperature control, water replenishment ratio adjustment and secondary utilization distribution of scarce water.

2. The steam production system for recovering waste heat from low-temperature dusty and highly acidic flue gas according to claim 1, characterized in that: The heat pipe heat exchanger (1) is an eccentric radial heat pipe heat exchanger, and its heat pipe elements are individually arranged and replaceable.

3. The steam production system for recovering waste heat from low-temperature dusty and highly acidic flue gas according to claim 1, characterized in that: The secondary utilization scenario (13) includes one or more of organic Rankine cycle power generation, slurry heating, flue gas washing water preheating, furnace cooling water preheating, wet electrolysis cell hot water supply or living area heating and water supply.

4. The steam production system for recovering waste heat from low-temperature dusty and highly acidic flue gas according to claim 1, characterized in that: The electronic control circuit is controlled by the following logic: When the inlet temperature sensor (4) detects that the circulating water temperature is lower than a set threshold, the closed preheating loop circulation is maintained; When the temperature reaches the threshold, the inlet electric-controlled three-way valve (2) and the water supply electric-controlled four-way valve (3) are switched to the main circuit, so that saturated water enters the flash tank (8); According to the feedback from the outlet temperature sensor (7), the high and low temperature water replenishment ratio of the water replenishment electric control four-way valve (3) is dynamically adjusted to control the mixed water temperature within the range of ±2°C.

5. A method for producing steam based on the system according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Low-temperature dusty and high-acid flue gas enters the heat source side of the heat pipe heat exchanger (1) to release heat, and after cooling down, enters the subsequent desulfurization and dust removal process; S2: Controlling the inlet electric-controlled three-way valve (2) and the water supply electric-controlled four-way valve (3) through the electric control circuit, so that the circulating water circulates in the closed preheating circuit until the inlet temperature sensor (4) detects that the circulating water temperature reaches a set threshold value; S3: After preheating is completed, the electronic control circuit switches the valve state, allowing the saturated water to enter the flash tank (8) for flash evaporation to generate low-pressure saturated steam; S4: the steam after flash evaporation is stabilized by the steam accumulator (11) and then enters the mechanical steam recompressor (12) for pressurization, and outputs steam at the target pressure; S5: the exhausted water after flash evaporation is distributed in proportion through the outlet electrically controlled three-way valve (10), one part of which is mixed with the low-temperature water in the circulating water supply tank (9) as high-temperature make-up water and then returned to the heat pipe heat exchanger (1), and the other part is transported to the secondary utilization scene (13) for waste heat recovery; S6: The outlet temperature sensor (7) is used to monitor the water supply temperature in real time, and the high and low temperature water supply mixing ratio of the water supply electric control four-way valve (3) is adjusted to ensure the stability of the working medium temperature at the inlet of the heat pipe heat exchanger (1).

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