A heat transfer system and its adjustment and control method

Abstract

The present invention discloses a heat transfer system and an adjustment control method thereof. The system includes: a hot flue unit, including a hot flue and a working medium heat absorber arranged in the hot flue; a cold flue unit, including a cold flue and a working medium heat releaser arranged in the cold flue; a heat medium water unit, including a heat medium water tank and a heat medium water pipeline connected in series with the working medium heat absorber, the heat medium water tank and the working medium heat releaser, the arrangement height of the heat medium water tank is higher than the arrangement height of the working medium heat absorber and the arrangement height of the working medium heat releaser; the heat medium water unit also includes a regulating bypass arranged in parallel with the working medium heat releaser, and a regulating valve and a heat regulating heat exchanger are arranged on the regulating bypass. The method is to adjust and control according to the operating load of the system and the relationship between the heat absorption of the working medium heat absorber and the heat release of the working medium heat releaser, so that the system is suitable for waste heat recovery of flue gas at 100 to 350°C. The present invention can adapt to a very wide range of flue gas temperature and working medium temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas waste heat recovery, and more specifically, to a heat transfer system and an adjustment and control method thereof. Background Art

[0002] In recent years, MGGH (or WGGH) system has been widely used in flue gas waste heat recovery and energy-saving and environmental protection projects. This system uses heat medium water to absorb high-temperature flue gas waste heat and then releases heat in low-temperature flue gas. Figure 1 The schematic diagram of the structure flow of the conventional MGGH closed circulation system in the prior art is shown as follows: Figure 1 As shown in the figure, this system usually adopts a closed heat medium water system. The heat medium water tank opening design is cut and the heat medium water tank is arranged at a high position. The working medium pressure in the MGGH system is maintained by the high position of the heat medium water tank. The general working medium operating pressure is 0.4-0.5MPa, and the working medium temperature is controlled within 150℃. At this time, there is no problem in the operation of the MGGH system. In this system, the heat medium water tank is used for water replenishment and pressure stabilization, not as a flow channel for the working medium. The heat medium water tank is a normal pressure device.

[0003] However, in the case of high flue gas temperature, such as gas boiler water-type gas heater, steel plant sintering machine or pelletizing project flue gas heating system, the flue gas temperature is generally high, the existing MGGH (or WGGH) system heating surface of the working fluid will appear vaporization and other phenomena, endangering the safe and stable operation of the system, conventional MGGH is no longer suitable for high flue gas temperature environment.

[0004] In order to solve the problem that the original MGGH (or WGGH) system has a small applicable range for flue gas temperature and working fluid temperature, it is necessary to provide a heat transfer system and an adjustment and control method thereof that can adapt to a very wide range of flue gas temperature and working fluid temperature. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention proposes a heat transfer system and an adjustment and control method thereof which can adapt to a very wide range of flue gas temperature and working fluid temperature.

[0006] One aspect of the present invention provides a heat transfer system, comprising:

[0007] A hot flue unit, comprising a hot flue and a working medium heat absorber arranged in the hot flue;

[0008] A cold flue unit, comprising a cold flue and a working medium heat release device arranged in the cold flue;

[0009] The heat medium water unit comprises a heat medium water tank and a heat medium water pipeline connected in series with the working medium heat absorber, the heat medium water tank and the working medium heat releaser, wherein the arrangement height of the heat medium water tank is higher than the arrangement height of the working medium heat absorber and the arrangement height of the working medium heat releaser; wherein the heat medium water unit further comprises a regulating bypass arranged in parallel with the working medium heat releaser, wherein the regulating bypass is provided with a regulating valve and a heat regulating heat exchanger.

[0010] According to an embodiment of the heat transfer system of the present invention, the heat medium water tank is a closed pressurized water tank and is provided with a liquid level gauge and a safety valve. The heat medium water tank is also connected to a water supply pipeline provided with a shut-off valve.

[0011] According to an embodiment of the heat transfer system of the present invention, a booster pump, a temperature monitoring thermocouple and a pressure transmitter are provided on the heat medium water pipeline between the working fluid heat absorber and the working fluid heat releaser, a temperature monitoring thermocouple and a pressure transmitter are provided on the heat medium water pipeline between the working fluid heat absorber and the heat medium water tank, a temperature monitoring thermocouple is provided on the heat medium water pipe between the heat medium water tank and the working fluid heat releaser, and a temperature monitoring thermocouple is provided at the outlet of the heat regulating heat exchanger in the regulating bypass.

[0012] According to an embodiment of the heat transfer system of the present invention, the heat regulating heat exchanger is connected to the cold medium source through a cold medium inlet pipe and a cold medium outlet pipe, a regulating valve is provided on the cold medium inlet pipe, and a shut-off valve is provided on the cold medium outlet pipe.

[0013] According to an embodiment of the heat transfer system of the present invention, temperature monitoring thermocouples are arranged before and after the working fluid heat absorber in the hot flue and before and after the working fluid heat releaser in the cold flue, wherein the medium in the hot flue is hot flue gas, and the medium in the cold flue is flue gas, air or coal gas, and the working fluid heat absorber or the working fluid heat releaser is a tubular heat exchanger or a plate heat exchanger.

[0014] According to an embodiment of the heat transfer system of the present invention, the working fluid outlet of the working fluid heat emitter is provided with a shut-off valve and the working fluid inlet is provided with a regulating valve, and the working fluid inlet and working fluid outlet of the working fluid heat absorber are both provided with shut-off valves.

[0015] Another aspect of the present invention provides an adjustment and control method for the above-mentioned heat transfer system, which performs adjustment and control according to the operating load of the system and the relationship between the heat absorption of the working fluid heat absorber and the heat release of the working fluid heat releaser, so that the system is suitable for flue gas waste heat recovery at 100-350°C.

[0016] According to an embodiment of the heat transfer system adjustment control method of the present invention, when the system operates at full load and the heat absorbed by the working fluid heat absorber is equal to the heat released by the working fluid heat releaser, the adjustment bypass is closed to make the system operate under the design conditions.

[0017] According to an embodiment of the heat transfer system adjustment control method of the present invention, when the system operates under low load and the heat absorbed by the working fluid heat absorber is equal to the heat released by the working fluid heat releaser, the regulating bypass is opened and the heat regulating heat exchanger is controlled not to be put into operation, and the heat medium water flow entering the working fluid heat releaser and the regulating bypass is adjusted to control the outlet flue gas temperature of the working fluid heat releaser, and at the same time, the outlet heat medium water of the working fluid heat releaser and the outlet heat medium water of the regulating bypass are controlled to reach the required temperature of the working fluid heat absorber after being mixed.

[0018] According to an embodiment of the adjustment and control method of the heat transfer system of the present invention, when the heat absorbed by the working fluid heat absorber is greater than the heat released by the working fluid heat releaser, the adjustment bypass is opened and the heat regulating heat exchanger is controlled to be put into operation, and the heat medium water flow entering the working fluid heat releaser and the heat regulating heat exchanger is adjusted respectively to control the outlet flue gas temperature of the working fluid heat releaser, and at the same time, the cold medium flow of the heat regulating heat exchanger is adjusted to adjust the outlet heat medium water temperature of the heat regulating heat exchanger, thereby adjusting the inlet heat medium water temperature of the working fluid heat absorber.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1) Applicable to a wider range of flue gas temperature and also to a wider range of working fluid temperature;

[0021] 2) The adjustment and control of the line are more flexible and convenient;

[0022] 3) The layout is more convenient, avoiding the need to place the heat medium water tank at a very high position in the conventional MGGH (or WGGH) system. The heat medium water tank only needs to be placed higher than the working medium heat absorber and working medium heat emitter;

[0023] 4) Adjust the heat transfer distribution of the system according to the changes in the system load; the end difference of the two heat exchangers can be artificially adjusted according to the increase or decrease in the area of ​​the heat exchangers of the working fluid heat absorber and the working fluid heat releaser, and the system design can be carried out based on the comprehensive cost and the impact of low-temperature corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure shows a schematic diagram of the structure flow of a conventional MGGH closed circulation system in the prior art.

[0025] Figure 2 A schematic structural flow diagram of a heat transfer system according to an exemplary embodiment of the present invention is shown.

[0026] Figure 3 A schematic diagram of the structural flow of the heat transfer system in Example 1 is shown.

[0027] Figure 4 A schematic diagram of the structural flow of the heat transfer system in Example 2 is shown.

[0028] Description of reference numerals:

[0029] 1-hot flue; 2-working fluid heat absorber; 3-boosting pump; 4-cold flue; 5-working fluid heat releaser; 6-heat regulating heat exchanger; 7-heat medium water tank; 8-liquid level gauge; 9-safety valve; 10-regulating bypass; 11-regulating valve; 12-shut-off valve; 13-temperature monitoring thermocouple; 14-pressure transmitter; 15-water supply pipeline; 16-heat medium water pipeline; 17-cold medium pipeline. DETAILED DESCRIPTION

[0030] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0031] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0032] The heat transfer system and the adjustment and control method thereof of the present invention are described in detail below with reference to the accompanying drawings.

[0033] Figure 2 A schematic structural flow diagram of a heat transfer system according to an exemplary embodiment of the present invention is shown.

[0034] like Figure 2 As shown, according to an exemplary embodiment of the present invention, the heat transfer system includes a hot flue unit, a cold flue unit and a heat medium water unit, wherein the hot flue unit is a component that uses a working fluid to exchange heat with hot flue gas, the cold flue unit is a component that uses cold flue gas to exchange heat with a working fluid after absorbing heat, and the heat medium water unit is a component that provides a working fluid and heat medium water circulation.

[0035] Specifically, the hot flue unit includes a hot flue 1 and a working medium heat absorber 2 arranged in the hot flue 1. The hot flue gas in the hot flue 1 can be hot flue gas from a boiler or hot flue gas from an industrial furnace such as steel; the working medium heat absorber 2 is arranged in the hot flue 1 and uses the working medium in the tube to absorb the heat of the flue gas. The working medium heat absorber 2 can be a tubular heat exchanger or a plate heat exchanger.

[0036] Similarly, the cold flue unit includes a cold flue 4 and a working medium heat release device 5 arranged in the cold flue 4. The medium in the cold flue 4 can be flue gas, air or coal gas, that is, it is not limited to the flue system, but can also be other medium pipeline systems. The working medium heat release device 5 is arranged in the cold flue 4, and uses the working medium in the pipe to heat the cold flue gas, air or coal gas in the cold flue. The working medium heat release device 5 can be a tubular heat exchanger or a plate heat exchanger.

[0037] The heat medium water unit includes a heat medium water tank 7 and a heat medium water pipe 16 that connects the working medium heat absorber 2, the heat medium water tank 7 and the working medium heat releaser 5 in series. That is, the heat medium water tank 7 is arranged in series in the heat medium water pipe 16 and is arranged in series in the system as a medium channel, which can be arranged horizontally or vertically. The arrangement height of the heat medium water tank 7 only needs to be higher than the arrangement height of the working medium heat absorber 2 and the arrangement height of the working medium heat releaser 5 to ensure that the pressure of the working medium in the heat medium water tank 7 is lower than that of the working medium heat absorber 2 and the working medium heat releaser 5, thereby ensuring that the working medium in the working medium heat absorber 2 and the working medium heat releaser 5 does not vaporize.

[0038] Preferably, the heat medium water tank 7 is a closed pressurized water tank and is provided with a level gauge 8 for measuring the liquid level of the heat medium water tank 7 and a safety valve 9 for safety protection of the system. The heat medium water tank 7 is also connected to a water supply pipe 15 provided with a shut-off valve 12. The water supply pipe 15 is used to supply water for the initial operation of the system, and the shut-off valve thereon can control the closure of the water supply pipe. Different from the heat medium water tank in the conventional normal pressure MGGH system solution, the working pressure of the heat medium water tank in this system is much higher than the atmospheric pressure. When the system is running, the pressure must be stable and not fluctuate sharply. The heat medium water tank relies on the internal steam-water phase change to play a role in stabilizing the pressure, and the water vapor ratio of the saturated steam-water mixture in the heat medium water tank is used to balance the system operating pressure.

[0039] According to the present invention, the heat medium water unit also includes a regulating bypass 10 arranged in parallel with the working medium heat release device 5, and the regulating bypass 10 is provided with a regulating valve 11 for regulating the pipeline flow and a heat regulating heat exchanger 6 for sending excess energy of the system to other places.

[0040] The regulating bypass 10 has two functions: one is that when the system needs to release heat to the outside of the system, the heat release is realized through the heat regulating heat exchanger; the other is that when the system does not need to release heat to the outside of the system, the cold medium pipeline on the heat regulating heat exchanger is closed and the heat regulating heat exchanger is only used as a medium channel. By adjusting the working fluid flow rate of the regulating bypass and the working fluid heat releaser, the inlet working fluid temperature of the working fluid heat absorber is adjusted.

[0041] The heat regulating heat exchanger 6 is connected to the cold medium source through the cold medium pipeline 17. The cold medium pipeline 17 includes a cold medium inlet pipeline and a cold medium outlet pipeline. A regulating valve is provided on the cold medium inlet pipeline, and a shut-off valve is provided on the cold medium outlet pipeline. The heat regulating heat exchanger 6 is arranged on the regulating bypass 10 and arranged in parallel with the working medium heat releaser 5. The heat regulating heat exchanger 6 is an optional device of the system, which can be used to send excess heat of the system to other places. The valve on the cold medium pipeline of the heat regulating heat exchanger can also be closed to make the heat regulating heat exchanger only as a medium channel to regulate the working medium temperature at the inlet of the working medium heat releaser.

[0042] Preferably, a booster pump 3, a temperature monitoring thermocouple 13 and a pressure transmitter 15 are provided on the heat medium water pipeline between the working fluid heat absorber 1 and the working fluid heat releaser 5, a temperature monitoring thermocouple 13 and a pressure transmitter 15 are provided on the heat medium water pipeline between the working fluid heat absorber 2 and the heat medium water tank 7, a temperature monitoring thermocouple 13 is provided on the heat medium water pipe between the heat medium water tank 7 and the working fluid heat releaser 5, and a temperature monitoring thermocouple 13 is provided at the outlet of the heat regulating heat exchanger 6 in the regulating bypass 10.

[0043] In addition, temperature monitoring thermocouples 13 are provided before and after the working medium heat absorber 2 in the hot flue 1 and before and after the working medium heat emitter 5 in the cold flue 4. A shut-off valve 12 is provided at the working medium outlet of the working medium heat emitter 5 and a regulating valve 11 is provided at the working medium inlet, and a shut-off valve 12 is provided at both the working medium inlet and the working medium outlet of the working medium heat absorber 2.

[0044] Among them, the regulating valve is used to adjust the flow of the corresponding pipeline, the shut-off valve is used to shut off the corresponding pipeline, the temperature detection thermocouple is used to measure the temperature and transmit the temperature signal to the control end for system control, and the pressure transmitter is used to measure the pressure of the corresponding pipeline and transmit the pressure signal to the control end for system control.

[0045] Thus, the heat medium water pipeline 16 connects the entire system into a closed heat medium water circulation system. The working medium in the closed heat medium water system follows the process of: booster pump → working medium heat absorber → heat medium water tank → working medium heat release device & regulating bypass (heat regulating heat exchanger) → booster pump, and the working medium in the pipeline is heat medium water.

[0046] The present invention also provides an adjustment and control method for the above-mentioned heat transfer system, which needs to be adjusted and controlled according to the operating load of the system and the relationship between the heat absorption of the working fluid heat absorber and the heat release of the working fluid heat releaser, so that the system is suitable for flue gas waste heat recovery at 100-350°C.

[0047] This system has three commonly used working modes, which are described in detail below.

[0048] The first one: When the system is running at full load and the amount of heat absorbed by the working fluid heat absorber is equal to the amount of heat released by the working fluid heat releaser, close the regulating bypass to make the system run under the design conditions.

[0049] When the system is running at full load and the amount of heat absorbed by the working fluid heat absorber is equal to the amount of heat released by the working fluid heat releaser, the system does not need to release heat to the outside. After adjusting the bypass to close, the system is at the designed operating point and can operate normally in sequence.

[0050] The second type: when the system is running at low load and the heat absorbed by the working fluid heat absorber is equal to the heat released by the working fluid heat releaser, the regulating bypass is opened and the heat regulating heat exchanger is controlled not to be put into operation, and the heat medium water flow entering the working fluid heat releaser and the regulating bypass is adjusted to control the outlet flue gas temperature of the working fluid heat releaser, and at the same time, the outlet heat medium water of the working fluid heat releaser and the outlet heat medium water of the regulating bypass are controlled to reach the required temperature of the working fluid heat absorber after being mixed.

[0051] When the system is running at low load and the amount of heat absorbed by the working fluid heat absorber is equal to the amount of heat released by the working fluid heat releaser, the system does not need to release heat to the outside. However, due to the mismatch in heat exchange areas between the working fluid heat absorber and the working fluid heat releaser, it is difficult to achieve a balance in the heat exchange of the two heat exchangers, and the bypass needs to be adjusted for adjustment. At this time, the bypass pipeline is put into operation.

[0052] However, because the system does not release heat to the outside, the heat regulating heat exchanger on the regulating bypass is not put into operation at this time, and the regulating bypass only serves as a medium channel. The flue gas temperature at the outlet of the working fluid heat releaser is controlled by adjusting the flow entering the working fluid heat releaser and the regulating bypass. At the same time, the temperature of the mixture of the heat medium water at the outlet of the working fluid heat releaser and the heat medium water in the regulating bypass is controlled to reach the temperature required by the working fluid heat absorber.

[0053] The control method is as follows: first, the total working fluid flow of the system is adjusted by the booster pump, and the inlet working fluid temperature of the working fluid heat absorber is adjusted at the same time, thereby controlling the outlet flue gas temperature of the working fluid heat absorber; the outlet flue gas temperature of the working fluid heat emitter is adjusted by adjusting the flow of the heat medium water entering the working fluid heat emitter, and the temperature monitoring thermocouple at the flue gas outlet of the working fluid heat emitter is associated with the regulating valve at the working fluid inlet of the working fluid heat emitter. The remaining heat medium water is mixed with the heat medium water at the outlet of the working fluid heat emitter after passing through the regulating bypass (not participating in heat exchange), and then enters the working fluid heat absorber through the booster pump.

[0054] The third method: when the heat absorbed by the working fluid heat absorber is greater than the heat released by the working fluid heat releaser, the regulating bypass is opened and the heat regulating heat exchanger is controlled to be put into operation, and the heat medium water flow entering the working fluid heat releaser and the heat regulating heat exchanger is adjusted respectively to control the outlet flue gas temperature of the working fluid heat releaser, and at the same time, the cold medium flow of the heat regulating heat exchanger is adjusted to adjust the outlet heat medium water temperature of the heat regulating heat exchanger, thereby adjusting the inlet heat medium water temperature of the working fluid heat absorber.

[0055] The control method is specifically as follows: first, the total working fluid flow of the system is adjusted by the booster pump, and the inlet working fluid temperature of the working fluid heat absorber is adjusted at the same time, thereby controlling the outlet flue gas temperature of the working fluid heat absorber; the outlet flue gas temperature of the working fluid heat releaser is adjusted by adjusting the flow of heat medium water entering the working fluid heat releaser, and the temperature monitoring thermocouple at the working fluid outlet of the working fluid heat releaser is associated with the regulating valve at the working fluid inlet of the working fluid heat releaser. The heat exchange of the heat regulating heat exchanger is controlled by adjusting the amount of cooling water entering the heat regulating heat exchanger, thereby controlling the outlet heat medium water temperature of the heat regulating heat exchanger, and finally controlling the temperature of the heat medium water at the outlet of the heat regulating heat exchanger and the outlet heat medium water of the working fluid heat releaser to meet the working fluid temperature requirement at the inlet of the working fluid heat absorber. The temperature monitoring thermocouple at the working fluid inlet of the working fluid heat releaser is associated with the regulating valve on the cold medium pipeline of the heat regulating heat exchanger.

[0056] This system can be used for indirect heating of coal gas by high-temperature flue gas in gas boilers to avoid leakage of coal gas during direct heating of flue gas by coal gas. It can also be used for indirect heating of low-temperature flue gas by high-temperature flue gas in the flue gas purification system at the tail of steel sintering machine to achieve flue gas reheating or denitrification. This system can be used to replace part of the tubular air preheater, saving the space occupied by the tubular air preheater to arrange the denitrification device, which is particularly suitable for the situation where the denitrification device is added in the transformation project but the space is tight. In addition, through the setting of the closed pressure heat medium water tank of this system, it is not only suitable for low parameters such as low heat medium water temperature, but also can be used for high parameters such as high heat medium water temperature and pressure to prevent the vaporization of heat medium water. By increasing the end difference of the heat exchanger of the working medium heat release device to reduce the area of ​​the working medium heat release device, especially when the working medium heat release device uses higher-grade steel (such as 2205 stainless steel or 316L stainless steel, etc.), the cost can be greatly reduced. By increasing the inlet and outlet working fluid temperatures of the working fluid heat absorber, the heat exchanger wall temperature of the working fluid heat absorber can be increased, thereby effectively reducing the risk of low-temperature corrosion of the working fluid heat absorber.

[0057] The present invention will be further described below in conjunction with specific embodiments.

[0058] Example 1: High-temperature flue gas from the boiler indirectly heats the blast furnace gas to preheat the gas

[0059] Design conditions: The temperature of the high-temperature flue gas from the boiler is ~280℃, and the temperature drops to 230℃ after heat release. The released heat is used to heat the 80℃ blast furnace gas to 170℃. The flue gas volume is 690,000 Nm 3 / h, gas volume 430,000 Nm 3 / h.

[0060] Figure 3 FIG. 1 shows a schematic diagram of the structure of the heat transfer system in Example 1. Figure 3As shown, the working medium heat absorber is arranged after the high-temperature air preheater and before the low-temperature air preheater, and the working medium heat releaser is arranged on the gas pipeline to heat the gas by recovering the heat of the high-temperature flue gas.

[0061] After the implementation of this system solution, the high-temperature hot flue gas from the boiler indirectly heats the blast furnace gas, avoiding the risk of gas leakage caused by the flue gas directly heating the blast furnace gas. In addition, the steam-water phase change inside the heat medium water tank in this embodiment stabilizes the system. The system working pressure is ~2.5MPa. When the boiler changes its working condition, the flue gas temperature and flue gas volume change. This system can be adjusted at any time with the change of the boiler working condition. At the same time, the waste heat of the flue gas can also be recovered to other systems by investing in a heat regulating heat exchanger, such as low-pressure condensate or hot network water.

[0062] Example 2: High-temperature flue gas from a steel sintering machine is used to indirectly heat the desulfurized clean flue gas for flue gas desulfurization

[0063] Design conditions: The high-temperature flue gas temperature from the steel sintering machine is ~310℃, and the temperature drops to 174℃ after heat release. The released heat is used to heat the 50℃ desulfurized clean flue gas to 80℃ for flue gas desulfurization. The high-temperature flue gas volume is 200,000 Nm 3 / h, net flue gas after desulfurization is 1.13 million Nm 3 / h.

[0064] Figure 4 The schematic diagram of the structure flow of the heat transfer system in Example 2 is shown. Figure 4 As shown, the working medium heat absorber is arranged in the high-temperature flue at the outlet of the sintering machine, and the working medium heat releaser is arranged on the outlet flue of the desulfurization tower. The heat of the high-temperature flue gas is recovered to heat the clean flue gas after desulfurization to eliminate the whitening.

[0065] Through the implementation of this system, the high-temperature hot flue gas from the sintering machine indirectly heats the clean flue gas after desulfurization, avoiding the layout difficulties caused by the high-temperature flue gas directly heating the clean flue gas after desulfurization. In addition, the steam-water phase change inside the heat medium water tank in this embodiment has a pressure stabilizing effect on the system. The system working pressure is ~0.8MPa. When the flue gas temperature and flue gas volume change, this system can be adjusted at any time according to the changes in the sintering machine working conditions.

[0066] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A heat transfer system, characterized in that: include: A hot flue unit, comprising a hot flue and a working medium heat absorber arranged in the hot flue; A cold flue unit, comprising a cold flue and a working medium heat release device arranged in the cold flue; A heat medium water unit, comprising a heat medium water tank and a heat medium water pipeline connected in series with the working medium heat absorber, the heat medium water tank and the working medium heat radiator, wherein the arrangement height of the heat medium water tank is higher than the arrangement height of the working medium heat absorber and the arrangement height of the working medium heat radiator; wherein the heat medium water unit further comprises a regulating bypass arranged in parallel with the working medium heat radiator, wherein the regulating bypass is provided with a regulating valve and a heat regulating heat exchanger; A booster pump, a temperature monitoring thermocouple and a pressure transmitter are provided on the heat medium water pipeline between the working medium heat absorber and the working medium heat emitter, a temperature monitoring thermocouple and a pressure transmitter are provided on the heat medium water pipeline between the working medium heat absorber and the heat medium water tank, a temperature monitoring thermocouple is provided on the heat medium water pipe between the heat medium water tank and the working medium heat emitter, and a temperature monitoring thermocouple is provided at the outlet of the heat regulating heat exchanger in the regulating bypass; the heat regulating heat exchanger is connected to the cold medium source through a cold medium inlet pipeline and a cold medium outlet pipeline, a regulating valve is provided on the cold medium inlet pipeline, and a shut-off valve is provided on the cold medium outlet pipeline; Temperature monitoring thermocouples are arranged before and after the working medium heat absorber in the hot flue and before and after the working medium heat emitter in the cold flue, wherein the medium in the hot flue is hot flue gas, and the medium in the cold flue is flue gas, air or coal gas, and the working medium heat absorber or working medium heat emitter is a tubular heat exchanger or a plate heat exchanger; The working fluid outlet of the working fluid heat emitter is provided with a shut-off valve and the working fluid inlet is provided with a regulating valve, and the working fluid inlet and the working fluid outlet of the working fluid heat absorber are both provided with shut-off valves.

2. The heat transfer system according to claim 1, characterized in that The heat medium water tank is a closed pressurized water tank and is provided with a liquid level gauge and a safety valve. The heat medium water tank is also connected to a water supply pipeline provided with a shut-off valve.

3. The heat transfer system adjustment and control method according to any one of claims 1 to 2, characterized in that: Adjustment and control are performed according to the operating load of the system and the relationship between the heat absorption of the working fluid heat absorber and the heat release of the working fluid heat releaser, so that the system is suitable for waste heat recovery of flue gas at 100-350°C.

4. The heat transfer system adjustment and control method according to claim 3, characterized in that: When the system operates at full load and the amount of heat absorbed by the working fluid heat absorber is equal to the amount of heat released by the working fluid heat releaser, the regulating bypass is closed to allow the system to operate under the designed operating conditions.

5. The heat transfer system adjustment and control method according to claim 4, characterized in that: When the system operates under low load and the heat absorbed by the working fluid heat absorber is equal to the heat released by the working fluid heat releaser, the regulating bypass is opened and the heat regulating heat exchanger is controlled not to be put into operation, and the heat medium water flow entering the working fluid heat releaser and the regulating bypass is adjusted to control the outlet flue gas temperature of the working fluid heat releaser, and at the same time, the outlet heat medium water of the working fluid heat releaser and the outlet heat medium water of the regulating bypass are controlled to reach the required temperature of the working fluid heat absorber after being mixed.

6. The heat transfer system adjustment and control method according to claim 5, characterized in that: When the heat absorbed by the working fluid heat absorber is greater than the heat released by the working fluid heat releaser, the regulating bypass is opened and the heat regulating heat exchanger is controlled to be put into operation. The heat medium water flow entering the working fluid heat releaser and the heat regulating heat exchanger is adjusted respectively to control the outlet flue gas temperature of the working fluid heat releaser. At the same time, the cold medium flow of the heat regulating heat exchanger is adjusted to adjust the outlet heat medium water temperature of the heat regulating heat exchanger, thereby adjusting the inlet heat medium water temperature of the working fluid heat absorber.

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