Flue gas waste heat recovery system and control method thereof

Abstract

The application discloses a flue gas waste heat recovery system and a control method thereof, and relates to the technical field of waste heat recovery.The flue gas waste heat recovery system comprises a first filter, a heat pipe heat exchanger, a first fan, an OVEN furnace, a second filter, a second fan, an air supply pipeline and an exhaust main pipeline.The air supply pipeline is sequentially connected with the first filter, a condensation section of the heat pipe heat exchanger, the first fan and an air inlet end of the OVEN furnace.The exhaust pipeline is sequentially connected with an air outlet end of the OVEN furnace, the second filter, an evaporation section of the heat pipe heat exchanger and the second fan.The application recovers the high-temperature waste heat in the exhaust gas discharged by the OVEN furnace by arranging the heat pipe heat exchanger, and uses the high-temperature waste heat to heat the air about to enter the OVEN furnace, thereby reducing the waste of waste heat resources and the energy consumption of the OVEN furnace and improving the high-temperature flue gas waste heat recovery rate.The application further discloses a control method of the flue gas waste heat recovery system, and is realized based on the above flue gas waste heat recovery system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste heat recovery, in particular to a flue gas waste heat recovery system and a control method thereof. BACKGROUND

[0002] A large amount of waste heat resources are not effectively utilized, resulting in energy waste and increased carbon emissions.

[0003] In the conventional technical solution, please refer to Figure 1 , the indoor clean air (about 25 DEG C) is directly introduced into the OVEN furnace, the high-temperature flue gas (230 DEG C) discharged from the OVEN furnace is heat-exchanged with the bypass-delivered clean room air (about 25 DEG C) to reduce the temperature, the exhaust gas (about 130 DEG C) after temperature reduction is introduced into the exhaust pipe, and the heat is directly discharged at the end of the exhaust pipe or recovered and converted into medium-temperature water for heating and other purposes. However, in this process, the high-temperature flue gas (230 DEG C) discharged from the OVEN furnace is directly mixed with the bypass-delivered clean room air (about 25 DEG C) to reduce the temperature, which causes a large amount of high-temperature waste heat to be degraded and wasted, resulting in high energy consumption of the factory. SUMMARY

[0004] The main purpose of the present application is to provide a flue gas waste heat recovery system and a control method thereof, which aims to improve the high-temperature flue gas waste heat recovery rate.

[0005] To achieve the above-mentioned purpose, the flue gas waste heat recovery system provided by the present application comprises a first filter, a heat pipe heat exchanger, a first fan, an OVEN furnace, a second filter, a second fan, an air supply pipeline and an exhaust air main pipeline; the air supply pipeline is connected in sequence with the first filter, the condensation section of the heat pipe heat exchanger, the first fan and the air inlet end of the OVEN furnace; the exhaust air pipeline is connected in sequence with the air outlet end of the OVEN furnace, the second filter, the evaporation section of the heat pipe heat exchanger and the second fan.

[0006] In an embodiment, the heat pipe heat exchanger comprises a high-temperature heat exchange module, a high-medium temperature combined heat exchange module, and a connecting pipe; the high-temperature heat exchange module is provided with an air supply pipe and an air exhaust pipe, the air supply pipe is located in the condensation section of the high-temperature heat exchange module and connected with the air supply pipe line, and the air exhaust pipe is located in the evaporation section of the high-temperature heat exchange module and connected with the air exhaust main pipe line; the high-medium temperature combined heat exchange module is also provided with an air supply pipe and an air exhaust pipe, the air supply pipe is located in the condensation section of the high-medium temperature combined heat exchange module and connected with the air supply pipe line, and the air exhaust pipe is located in the evaporation section of the high-medium temperature combined heat exchange module and connected with the air exhaust main pipe line; one of the connecting pipes connects the air supply pipe in the high-temperature heat exchange module with the air supply pipe in the high-medium temperature combined heat exchange module, and the other connecting pipe connects the air exhaust pipe in the high-temperature heat exchange module with the air exhaust pipe in the high-medium temperature combined heat exchange module; the high-temperature heat exchange module and the high-medium temperature combined heat exchange module are both provided with heat exchange pipes, one end of the heat exchange pipe penetrates into the air supply pipe, the other end of the heat exchange pipe penetrates into the air exhaust pipe, the outer wall of the heat exchange pipe located in the air supply pipe is provided with heat dissipation fins, a steam cavity is formed in the heat exchange pipe, and the steam cavity contains heat exchange working medium.

[0007] In an embodiment, the flue gas waste heat recovery system further comprises a first differential pressure gauge and a cleaning device, the first differential pressure gauge is connected in parallel with the evaporation section of the heat pipe heat exchanger and used for monitoring the differential pressure of the evaporation section of the heat pipe heat exchanger, the cleaning device is connected with the evaporation section of the heat pipe heat exchanger, and the first differential pressure gauge is communicatively connected with the cleaning device; and / or, the flue gas waste heat recovery system further comprises a second differential pressure gauge, the second differential pressure gauge is connected in parallel with the second filter and used for monitoring the differential pressure of the second filter.

[0008] In an embodiment, the flue gas waste heat recovery system further comprises a control system, the control system comprises a first terminal controller and a second terminal controller, and the OVEN furnace is provided with an electric heating pipe; the first terminal controller and the second terminal controller are both connected with the electric heating pipe and used for monitoring the actual power of the electric heating pipe; the first terminal controller is connected with the first fan and used for controlling the rotating speed of the first fan, and the second terminal controller is connected with the second fan and used for controlling the rotating speed of the second fan.

[0009] In an embodiment, the control system further comprises a first temperature sensor, a second temperature sensor, a third temperature sensor and a fourth temperature sensor; the first temperature sensor is arranged at the input end of the condensing section of the heat pipe heat exchanger, the second temperature sensor is arranged at the output end of the condensing section of the heat pipe heat exchanger, and the first temperature sensor and the second temperature sensor are both in communication connection with the first terminal controller; the third temperature sensor is arranged at the input end of the evaporating section of the heat pipe heat exchanger, and the fourth temperature sensor is arranged at the output end of the evaporating section of the heat pipe heat exchanger, and the third temperature sensor and the fourth temperature sensor are both in communication connection with the second terminal controller.

[0010] In an embodiment, a first valve is arranged on the air supply pipeline, and the first valve is located between the first fan and the OVEN furnace; a second valve and a third valve are arranged on the air exhaust pipeline, the second valve is located between the OVEN furnace and the second filter, and the third valve is located between the heat pipe heat exchanger and the second fan.

[0011] In an embodiment, the flue gas waste heat recovery system further comprises an air exhaust branch pipeline, one end of the air exhaust branch pipeline is connected with the air outlet end of the OVEN furnace, the other end of the air exhaust branch pipeline is connected with the second fan, and a fourth valve is arranged on the air exhaust branch pipeline.

[0012] The application further provides a control method of a flue gas waste heat recovery system.

[0013] The control method of the flue gas waste heat recovery system comprises the following steps:

[0014] The actual power and the rated power of the electric heating pipe are obtained;

[0015] The actual air volume of the flue gas waste heat recovery system is adjusted according to the proportion of the actual power relative to the rated power;

[0016] The actual power of the electric heating pipe is adjusted according to the temperature value monitored by the second temperature sensor.

[0017] In an embodiment, the step of adjusting the air volume of the flue gas waste heat recovery system according to the proportion of the actual power relative to the rated power specifically comprises the following steps:

[0018] The operation mode of the flue gas waste heat recovery system is selected according to the proportion of the actual power relative to the rated power, wherein the operation mode includes three modes of normal mode, IDLE mode and DOWN mode.

[0019] The normal mode is selected when the actual power is greater than or equal to 70% of the rated power, the IDLE mode is selected when the actual power is greater than 30% of the rated power and less than 70% of the rated power, and the DOWN mode is selected when the actual power is less than 30% of the rated power.

[0020] The actual air volume of the flue gas waste heat recovery system is adjusted according to the operation mode:

[0021] When the operation mode is the normal mode, the actual air volume of the flue gas waste heat recovery system is adjusted to be 100% of the rated air volume; when the operation mode is the IDLE mode, the actual air volume of the flue gas waste heat recovery system is adjusted to be 50% to 70% of the rated air volume; and when the operation mode is the DOWN mode, the actual air volume of the flue gas waste heat recovery system is adjusted to be 20% to 30% of the rated air volume.

[0022] In an embodiment, the set value of the inlet air temperature of the OVEN furnace is A℃ to B℃, and A < B;

[0023] The step of adjusting the actual power of the electric heating pipe according to the temperature value monitored by the second temperature sensor specifically comprises the following steps:

[0024] The temperature value monitored by the second temperature sensor is obtained;

[0025] The size of the temperature value monitored by the second temperature sensor is judged:

[0026] If the temperature value monitored by the second temperature sensor is less than A, the actual power of the electric heating pipe is increased;

[0027] If the temperature value monitored by the second temperature sensor is greater than B, the actual power of the electric heating pipe is decreased;

[0028] If A is less than or equal to the temperature value monitored by the second temperature sensor and is less than or equal to B, the adjustment is ended.

[0029] The flue gas waste heat recovery system comprises a first filter, a heat pipe heat exchanger, a first fan, an OVEN furnace, a second filter, a second fan, an air supply pipeline and an air exhaust main pipeline. The air supply pipeline is sequentially connected with the first filter, a condensation section of the heat pipe heat exchanger, the first fan and an air inlet end of the OVEN furnace. The air exhaust pipeline is sequentially connected with an air outlet end of the OVEN furnace, the second filter, an evaporation section of the heat pipe heat exchanger and the second fan. The high-temperature waste heat in the exhaust gas discharged from the OVEN furnace is recovered by the heat pipe heat exchanger and used to heat the air about to enter the OVEN furnace, so that the waste of waste heat resources and the energy consumption of the OVEN furnace are reduced, and the high-temperature flue gas waste heat recovery rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the flue gas emission process in conventional technologies;

[0032] Figure 2 This is a schematic diagram of the flue gas emission process in the flue gas waste heat recovery system provided by the present invention.

[0033] Figure 3 This is a schematic diagram of a structure of an embodiment of the flue gas waste heat recovery system provided by the present invention;

[0034] Figure 4 for Figure 3 A schematic diagram of an embodiment of a medium-heat pipe heat exchanger;

[0035] Figure 5 for Figure 4 A schematic diagram of the structure of one embodiment of the heat exchanger tube;

[0036] Figure 6 A flowchart of an embodiment of the control method for the flue gas waste heat recovery system provided by the present invention;

[0037] Figure 7 This is a flowchart of another embodiment of the control method for the flue gas waste heat recovery system provided by the present invention.

[0038] Explanation of icon numbers:

[0039] 100. Flue gas waste heat recovery system;

[0040] 1. First filter;

[0041] 2. Heat pipe heat exchanger; 2A. High temperature heat exchange module; 2B. High- and medium-temperature combined heat exchange module; 2C. Connecting pipe; 21. Air supply pipe; 22. Air exhaust pipe; 23. Heat exchange tube; 231. Outer shell; 232. Liquid suction core; 233. Heat dissipation fins; 23a. Steam chamber;

[0042] 3. First blower; 4. Oven; 5. Second filter; 6. Second blower;

[0043] 7. Air supply duct; 71. First valve;

[0044] 8. Main exhaust pipe; 81. Second valve; 82. Third valve;

[0045] 9, first differential pressure gauge; 10, second differential pressure gauge; 11, first temperature sensor; 12, second temperature sensor; 13, third temperature sensor; 14, fourth temperature sensor;

[0046] 15, exhaust branch line; 151, fourth valve.

[0047] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0049] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0050] In addition, if the embodiments of the present application involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0051] The present application provides a flue gas waste heat recovery system 100.

[0052] Please refer to Figures 2 to 3In an embodiment of the present application, the flue gas waste heat recovery system 100 comprises a first filter 1, a heat pipe heat exchanger 2, a first fan 3, an OVEN furnace 4, a second filter 5, a second fan 6, an air supply pipeline 7, and an exhaust main pipeline 8. The air supply pipeline 7 is connected in sequence to the first filter 1, a condensation section of the heat pipe heat exchanger 2, the first fan 3, and an air inlet end of the OVEN furnace 4. The exhaust main pipeline 8 is connected in sequence to an air outlet end of the OVEN furnace 4, the second filter 5, an evaporation section of the heat pipe heat exchanger 2, and the second fan 6.

[0053] In this embodiment, the air supply pipeline 7 is used to deliver fresh air to the OVEN furnace 4, and the high-temperature flue gas discharged by the OVEN furnace 4 is discharged through the exhaust main pipeline 8. In order to improve the waste heat recovery rate of the high-temperature flue gas, the flue gas waste heat recovery system 100 of the present application further comprises the heat pipe heat exchanger 2. The evaporation section of the heat pipe heat exchanger 2 is connected to the exhaust main pipeline 8, and the condensation section of the heat pipe heat exchanger 2 is connected to the air supply pipeline 7. The heat pipe heat exchanger 2 is used to recover the heat of the high-temperature flue gas in the exhaust main pipeline 8 and transfer it to the air supply pipeline 7 for heating the fresh air about to enter the OVEN furnace 4.

[0054] Specifically, 25℃ external fresh air enters the condensation section of the heat pipe heat exchanger 2 in sequence through the first filter 1 and the air supply pipeline 7, and after being preheated by the heat pipe heat exchanger 2, the temperature of the gas is about 185℃. After passing through the first fan 3, the gas enters the OVEN furnace 4 to participate in industrial production. The OVEN furnace 4 generates high-temperature flue gas at about 230℃, which is led out through the exhaust main pipeline 8, and after removing oil mist particles through the second filter 5, the flue gas enters the evaporation section of the heat pipe heat exchanger 2. After heat exchange through the heat pipe heat exchanger 2, the temperature of the hot exhaust gas is about 70℃, and then after passing through the second fan 6, the hot exhaust gas is discharged or subjected to the next recovery. The waste heat recovery of the high-temperature flue gas is realized, the waste heat recovery rate is improved, and the boiler operation energy consumption is reduced. Moreover, the process can be controlled by the control system through the feedback of signals such as temperature, pressure, and pressure difference in the system, the air volume of the system is controlled, the operation mode is changed, and the reliable operation of the system is ensured. The first filter 1 is used to filter dust and other impurities in the air to prevent the impurities from entering the OVEN furnace 4 and affecting industrial production. The second filter 5 is used to filter oil stain particles and the like discharged by the OVEN furnace 4 to avoid the clogging of the heat pipe heat exchanger 2 by oil stains and the like, which leads to a decrease in heat exchange efficiency. The first fan 3 can be preferably an axial flow fan, and the second fan 6 can be preferably a centrifugal fan. It should be noted that in the evaporation section of the heat pipe heat exchanger 2, the refrigerant in the heat pipe heat exchanger 2 absorbs heat and evaporates into a gaseous state and flows to the condensation section of the heat pipe heat exchanger 2. In the condensation section, the refrigerant releases heat and condenses into a liquid state and flows back to the evaporation section for the next cycle.

[0055] The flue gas waste heat recovery system 100 provided by the embodiment comprises a first filter 1, a heat pipe heat exchanger 2, a first fan 3, an OVEN furnace 4, a second filter 5, a second fan 6, an air supply pipeline 7 and an air exhaust main pipeline 8; the air supply pipeline 7 is sequentially connected with the first filter 1, a condensing section of the heat pipe heat exchanger 2, the first fan 3 and an air inlet end of the OVEN furnace 4; the air exhaust main pipeline 8 is sequentially connected with an air outlet end of the OVEN furnace 4, the second filter 5, an evaporating section of the heat pipe heat exchanger 2 and the second fan 6. The high-temperature waste heat in the exhaust gas discharged by the OVEN furnace 4 is recovered by arranging the heat pipe heat exchanger 2, and is used to heat the air about to enter the OVEN furnace 4, so that the waste of waste heat resources and the energy consumption of the OVEN furnace 4 are reduced, and the high-temperature flue gas waste heat recovery rate is improved.

[0056] Further, please refer to Figures 3 to 5 In an embodiment of the present application, the heat pipe heat exchanger 2 comprises a high-temperature heat exchange module 2A, a high-medium temperature combined heat exchange module 2B and a connecting pipe 2C; the high-temperature heat exchange module 2A is provided with an air supply pipe 21 and an air exhaust pipe 22, the air supply pipe 21 is located in a condensing section of the high-temperature heat exchange module 2A and is connected with the air supply pipeline 7, and the air exhaust pipe 22 is located in an evaporating section of the high-temperature heat exchange module 2A and is connected with the air exhaust main pipeline 8; and the high-medium temperature combined heat exchange module 2B is provided with another air supply pipe 21 and another air exhaust pipe 22, the other air supply pipe 21 is located in a condensing section of the high-medium temperature combined heat exchange module 2B and is connected with the air supply pipeline 7, and the other air exhaust pipe 22 is located in an evaporating section of the high-medium temperature combined heat exchange module 2B and is connected with the air exhaust main pipeline 8; a connecting pipe 2C connects the air supply pipe 21 in the high-temperature heat exchange module 2A with the air supply pipe 21 in the high-medium temperature combined heat exchange module 2B, and another connecting pipe 2C connects the air exhaust pipe 22 in the high-temperature heat exchange module 2A with the air exhaust pipe 22 in the high-medium temperature combined heat exchange module 2B; wherein the high-temperature heat exchange module 2A and the high-medium temperature combined heat exchange module 2B are both provided with heat exchange pipes 23, in each module, one end of the heat exchange pipe 23 penetrates into the air supply pipe 21, the other end of the heat exchange pipe 23 penetrates into the air exhaust pipe 22, the outer wall of the heat exchange pipe 23 located in the air supply pipe 21 is provided with heat dissipation fins 233, a steam cavity 23a is formed in the heat exchange pipe 23, and the steam cavity 23a contains heat exchange working medium.

[0057] In the embodiment, the heat pipe heat exchanger 2 is adopted, the evaporation temperature of the heat exchange working medium in the heat exchange pipe 23 is controlled by adjusting the system pressure, and the high-temperature flue gas heat is recovered. The liquid heat exchange working medium absorbs heat and evaporates into a gaseous state in the evaporating section of the heat pipe heat exchanger 2, and moves to the condensing section of the heat pipe heat exchanger 2, the gaseous heat exchange working medium releases heat and condenses into a liquid state in the condensing section of the heat pipe heat exchanger 2, and flows back to the evaporating section of the heat pipe heat exchanger 2, so that the temperature conversion between the clean fresh air and the high-temperature flue gas is efficiently realized.

[0058] Specifically, the heat exchange principle of the heat exchange pipe 23 is to use evaporative refrigeration to generate a temperature difference between the two ends of the heat exchange pipe 23, so that heat is quickly conducted. The inside of the heat exchange pipe 23 is in a vacuum state, and is filled with a suitable heat exchange working medium, such as methanol, propanol, water, ammonia, etc. The boiling point can be controlled by adjusting the pressure in the heat exchange pipe 23, so as to realize differentiated evaporation temperature under different working conditions. The heat exchange pipe 23 includes a shell 231 and a wick 232. The shell 231 forms an evaporation cavity containing the heat exchange working medium. The inner wall of the shell 231 is provided with the wick 232, which is composed of capillary porous material. It should be noted that one end of the heat exchange pipe 23 is the evaporation end, which is located in the evaporation section of the heat pipe heat exchanger 2. The evaporation section is a section of the exhaust pipe 22. The other end of the heat exchange pipe 23 is the condensation end, which is located in the condensation section of the heat pipe heat exchanger 2. The condensation section is a section of the air supply pipe 21. The description of the evaporation section and the condensation section of the heat pipe heat exchanger 2 in this application can be referred to the above description. When the evaporation end of the heat exchange pipe 23 is heated, the liquid in the evaporation cavity of the evaporation end rapidly evaporates. The vapor flows to the condensation end under a small pressure difference and releases heat, recondenses into liquid, and the liquid flows back to the evaporation end along the porous material under the action of capillary force, and the cycle continues. The heat is transferred from the evaporation end to the condensation end of the heat pipe. This cycle is fast and heat can be continuously conducted. The middle partition plate of the heat pipe heat exchanger 2 can completely separate the cold and hot fluids. Even if a single heat exchange pipe 23 is damaged due to wear, corrosion, over-temperature, etc. during operation, the fluids in the condensation section and the evaporation section will not leak and mix. The head end of each heat exchange pipe 23 is located in the evaporation section, and the welded end is located in the condensation section. Even if leakage occurs, it will not affect the OVEN furnace 4. The cold and hot fluids of the heat pipe heat exchanger 2 flow completely separately and in opposite directions, i.e. the flow directions of the new air and the high-temperature flue gas are opposite. The counter-flow heat exchange of the cold and hot fluids can be easily realized, and sufficient heat exchange between the new air and the high-temperature flue gas is ensured. The cold and hot fluids flow outside the pipe. Since the heat transfer coefficient of the pipe outside flow is much higher than that of the pipe inside flow, it is very economical for low-grade heat recovery. The outer wall of the heat exchange pipe 23 in the condensation section is provided with a heat dissipation fin 233, and the outer wall of the heat exchange pipe 23 in the evaporation section is a light pipe wall. It should be noted that the heat pipe heat exchanger 2 can solve the problem of internal wear and ash accumulation by changing the structure and expanding the heating surface. Since fresh air without oil stains is introduced into the condensation section, heat dissipation fins 233 can be arranged on the outer wall of the heat exchange pipe 23 in the condensation section to improve the heat exchange efficiency. The flue gas in the evaporation section still contains a small amount of oil mist after filtration. In order to facilitate cleaning and prolong the service life, the outer wall of the heat exchange pipe 23 in the evaporation section adopts a light pipe structure to reduce oil mist adhesion and facilitate cleaning.

[0059] More specifically, the heat pipe heat exchanger 2, the cold and hot fluids are separated by the intermediate partition, that is, the intermediate partition is used between the fresh air and the high temperature flue gas, and the intermediate partition separates the heat pipe heat exchanger 2 into the air supply pipe 21 and the exhaust pipe 22 which are independent of each other. The heat exchange pipe 23 is provided in the intermediate partition, and the heat exchange pipe 23 is connected with the partition by full welding. In order to realize the step-by-step recovery of heat, the heat pipe heat exchanger 2 of the embodiment adopts two-stage heat recovery, which includes a high-temperature heat exchange module 2A and a high-medium temperature combined heat exchange module 2B, and the two modules are connected together through a connecting pipe 2C. Each module includes an air supply pipe 21, an exhaust pipe 22 and a heat exchange pipe 23. The connecting pipe 2C can be connected by full welding flange SUS304 stainless steel, and the connecting pipe 2C is wrapped with insulation material, which can be glass fiber board, foam, etc. The connecting pipe 2C can be protected by an outer aluminum plate with fine lines. The joint of the connecting pipe 2C is sealed by rivets or sealing strips. By adjusting the system pressure, the evaporation temperature of the medium in the heat pipe is controlled, and the step-by-step recovery of the high temperature flue gas heat is realized. The outer wall of the condensing end of the heat exchange pipe 23 is provided with a fin structure, and the outer wall of the evaporation end of the heat exchange pipe 23 is a light pipe structure. Since the evaporation end of the heat exchange pipe 23 is in contact with the high temperature flue gas discharged from the OVEN furnace 4, the setting facilitates the cleaning of the small amount of oil mist after the high temperature flue gas is filtered, and prolongs the service life. In addition, the heat pipe heat exchanger 2 of the embodiment includes a high-temperature heat exchange module 2A, a high-medium temperature combined heat exchange module 2B and a connecting pipe 2C, that is, two-stage heat exchange modules are used. Compared with the traditional heat exchanger, when the temperature difference is large, for example, from 230°C to 70°C in the embodiment, the heat exchange is insufficient, which leads to low heat recovery rate and energy waste. The two-stage heat exchange module of the embodiment can adapt to the gradient of heat change, realize step-by-step heat recovery, and improve the heat recovery rate.

[0060] The flue gas (about 230°C) generated by the OVEN furnace 4 is introduced and filtered to remove oil mist particles, and then exchanges heat with the evaporation end of the heat exchange pipe 23 in the heat exchanger 2. Specifically, it first exchanges heat in the high-temperature heat exchange module 2A to reduce the temperature to T1, and then exchanges heat in the high-medium temperature combined heat exchange module to reduce the temperature to about 70°C, and finally is discharged into the external exhaust pipe through the second fan 6. The external fresh air at about 25°C is treated by the first filter 1 and then enters the condensing section of the heat pipe heat exchanger 2, first exchanges heat in the high-medium temperature combined heat exchange module to increase the temperature to T2, and then exchanges heat in the high-temperature heat exchange module 2A to increase the temperature to about 185°C, and then enters the OVEN furnace through the first fan 3 for recycling.

[0061] Further, please refer to Figure 3In an embodiment of the present application, the flue gas waste heat recovery system 100 further comprises a first differential pressure gauge 9 and a cleaning device, the first differential pressure gauge 9 is arranged in parallel with the evaporation section of the heat pipe heat exchanger 2 and is used to monitor the pressure difference of the evaporation section of the heat pipe heat exchanger 2, the cleaning device is connected with the evaporation section of the heat pipe heat exchanger 2, and the first differential pressure gauge 9 is in communication connection with the cleaning device; and / or, the flue gas waste heat recovery system 100 further comprises a second differential pressure gauge 10, the second differential pressure gauge 10 is arranged in parallel with the second filter 5 and is used to monitor the pressure difference of the second filter 5.

[0062] In the present embodiment, the flue gas waste heat recovery system 100 further comprises a first differential pressure gauge 9 and a cleaning device, the evaporation section of the heat pipe heat exchanger 2 is provided with the first differential pressure gauge 9 at both ends, that is, the first differential pressure gauge 9 is arranged in parallel with the evaporation section of the heat pipe heat exchanger 2 and is used to monitor the pressure difference of the evaporation section of the heat pipe heat exchanger 2. The evaporation section of the heat pipe heat exchanger 2 is provided with a cleaning water inlet and a cleaning water outlet which are in communication with the exhaust pipe 22, and the cleaning device is connected with the evaporation section of the heat pipe heat exchanger 2 and is in communication with the cleaning water inlet. The first differential pressure gauge 9 is in communication connection with the cleaning device, and the cleaning device can obtain the pressure difference information monitored by the first differential pressure gauge 9 to determine whether the evaporation section of the heat pipe heat exchanger 2 needs to be cleaned. That is, by monitoring the pressure difference of the evaporation section of the heat pipe heat exchanger 2 in real time, and being linked with the cleaning device, it can prevent the heat pipe heat exchanger 2 from being seriously blocked. For the fluid with high dust content, the heat pipe heat exchanger 2 can solve the problems of heat pipe heat exchanger 2 wear and dust blocking by changing the structure and expanding the heating surface. The second differential pressure gauge 10 is arranged in parallel with the second filter 5 to facilitate the online replacement of the filter element of the second filter 5, and the second differential pressure gauge 10 monitors the pressure difference between both ends of the second filter 5 in real time. When the pressure difference exceeds the designed pressure difference range, it indicates that the filter element is blocked, and the staff can be prompted to replace the filter element. It should be noted that the communication connection in the present application can be realized by direct electrical connection through wires or wireless connection, and can be realized by referring to the prior art. The same applies to subsequent embodiments, so it will not be described here.

[0063] Further, please refer to Figure 3 In an embodiment of the present application, the flue gas waste heat recovery system 100 further comprises a control system, the control system comprises a first terminal controller and a second terminal controller, and the OVEN furnace 4 is provided with an electric heating pipe; the first terminal controller and the second terminal controller are both connected with the electric heating pipe and are used to monitor the actual power of the electric heating pipe; the first terminal controller is connected with the first fan 3 and is used to control the rotating speed of the first fan 3, and the second terminal controller is connected with the second fan 6 and is used to control the rotating speed of the second fan 6.

[0064] In the embodiment, in order to ensure that the system operation fully meets the process requirements and saves system energy consumption, the air volume of the first fan 3 and the second fan 6 can be self-adaptively adjusted. The first terminal controller can adjust the rotating speed of the first fan 3 according to the power of the electric heating pipe, and then adjust the air inlet volume. Similarly, the second terminal controller can adjust the rotating speed of the second fan 6 according to the power of the electric heating pipe, and then adjust the air outlet volume. In this way, different air volumes can be output according to the power of the OVEN furnace 4 under different working conditions, for example, when the power of the OVEN furnace 4 increases, the output air volume increases, and when the power of the OVEN furnace 4 decreases, the output air volume decreases, so that the fan is always matched with the power of the OVEN furnace 4, and the waste of fan energy consumption is avoided, and the normal operation of industrial production is ensured.

[0065] Further, please refer to Figure 3 In an embodiment of the present application, the control system further comprises a first temperature sensor 11, a second temperature sensor 12, a third temperature sensor 13 and a fourth temperature sensor 14; the first temperature sensor 11 is arranged at the input end of the condensation section of the heat pipe heat exchanger 2, the second temperature sensor 12 is arranged at the output end of the condensation section of the heat pipe heat exchanger 2, and the first temperature sensor 11 and the second temperature sensor 12 are both in communication connection with the first terminal controller; the third temperature sensor 13 is arranged at the input end of the evaporation section of the heat pipe heat exchanger 2, and the fourth temperature sensor 14 is arranged at the output end of the evaporation section of the heat pipe heat exchanger 2; the third temperature sensor 13 and the fourth temperature sensor 14 are both in communication connection with the second terminal controller.

[0066] In the embodiment, the first temperature sensor 11 and the second temperature sensor 12 are used to monitor the temperature of the condensation section of the heat pipe heat exchanger 2 and calculate the temperature difference, so that the heat exchange efficiency of the condensation section of the heat pipe heat exchanger 2 can be calculated; when the heat exchange rate of the condensation section of the heat pipe heat exchanger 2 is reduced due to dust accumulation and other reasons, the first terminal controller can find this situation through the temperature values fed back by the first temperature sensor 11 and the second temperature sensor 12, so as to increase the air volume of the first fan 3 to ensure the supply of heat exchange amount. Similarly, the third temperature sensor 13 and the fourth temperature sensor 14 are used to monitor the temperature of the evaporation section of the heat pipe heat exchanger 2 and calculate the temperature difference, so that the heat exchange efficiency of the evaporation section of the heat pipe heat exchanger 2 can be calculated; when the heat exchange rate of the evaporation section of the heat pipe heat exchanger 2 is reduced due to dust accumulation, oil stains and other reasons, the second terminal controller can find this situation through the temperature values fed back by the third temperature sensor 13 and the fourth temperature sensor 14, so as to increase the air volume of the second fan 6 to ensure the supply of heat exchange amount. It should be noted that when the temperature difference exceeds the design range, the adjustment of the first fan 3 and the second fan 6 may not be able to effectively solve the problem of heat exchange rate reduction caused by dust accumulation, oil stain attachment and other reasons in the heat pipe heat exchanger 2, at this time, the heat pipe heat exchanger 2 can be quickly found through the temperature sensors and cleaned.

[0067] Further, please refer to Figure 3 In an embodiment of the present application, the air supply pipeline 7 is provided with a first valve 71, which is located between the first fan 3 and the OVEN furnace 4; the air exhaust main pipeline 8 is provided with a second valve 81 and a third valve 82, the second valve 81 is located between the OVEN furnace 4 and the second filter 5, and the third valve 82 is located between the heat pipe heat exchanger 2 and the second fan 6.

[0068] In this embodiment, considering that the heat pipe heat exchanger 2 may need to be maintained or cleaned after long-term use, in the maintenance and cleaning working condition, in order to avoid the pollution such as dust from escaping to the OVEN furnace 4 and affecting the normal working condition or causing pollution, the air supply pipeline 7 between the first fan 3 and the OVEN furnace 4 is provided with a first valve 71, the air exhaust main pipeline 8 between the OVEN furnace 4 and the second filter 5 is provided with a second valve 81, and the third valve 82 is provided between the heat pipe heat exchanger 2 and the second fan 6. And by setting the above valve, the opening of the air supply or exhaust pipeline 22 can be adjusted, so as to facilitate the adjustment of the flow in the pipeline.

[0069] Further, please refer to Figure 3 In an embodiment of the present application, the flue gas waste heat recovery system 100 further comprises an air exhaust branch pipeline 15, one end of the air exhaust branch pipeline 15 is connected with the air outlet end of the OVEN furnace 4, the other end of the air exhaust branch pipeline 15 is connected with the second fan 6, and the air exhaust branch pipeline 15 is provided with a fourth valve 151.

[0070] In this embodiment, considering that the heat pipe heat exchanger 2 may need to be maintained or cleaned after long-term use, in the maintenance and cleaning working condition, in order to avoid the whole system from stopping to cause loss, the air exhaust branch pipeline 15 is arranged on the air exhaust main pipeline 8, one end of the air exhaust branch pipeline 15 is connected with the air outlet end of the OVEN furnace 4, and the other end of the air exhaust branch pipeline 15 is connected with the second fan 6. If the heat pipe heat exchanger 2 needs to be repaired, the air exhaust main pipeline 8 can be closed, and the air exhaust branch pipeline 15 is used, so that the high-temperature flue gas can be temporarily discharged from the air exhaust branch pipeline 15, so as to ensure the normal operation of industrial production. The end of the air exhaust branch pipeline 15 away from the OVEN furnace 4 is provided with a new air inlet, and the high-temperature flue gas and the low-temperature new air are mixed in the air exhaust branch pipeline 15 and then discharged into the air exhaust main pipeline 8.

[0071] The present application also provides a control method of the flue gas waste heat recovery system 100, which is realized based on the flue gas waste heat recovery system 100 in the above embodiment.

[0072] Please refer to Figure 6 In an embodiment of the present application, the control method of the flue gas waste heat recovery system 100 comprises the following steps:

[0073] The actual power and the rated power of the electric heating pipe are obtained;

[0074] According to the proportion of the actual power relative to the rated power, the actual air volume of the flue gas waste heat recovery system 100 is adjusted;

[0075] According to the temperature value monitored by the second temperature sensor 12, the actual power of the electric heating pipe is adjusted.

[0076] In the embodiment, in order to make the air volume in the flue gas waste heat recovery system 100 just meet the industrial production, that is, to make the air volume in the flue gas waste heat recovery system 100 and the power of the electric heating pipe match each other, the actual power and the rated power of the electric heating pipe are obtained by the first terminal controller and used to adjust the rotating speed of the first fan 3 and then adjust the air volume of the first fan 3, wherein the rated power can be inputted by preset, and in the case of not replacing the fan, the input can be performed once initially, and the actual power needs to be obtained by the first terminal controller. Similarly, the actual power and the rated power of the electric heating pipe are obtained by the second terminal controller and used to adjust the rotating speed of the second fan 6 and then adjust the air volume of the second fan 6, wherein the rated power can be inputted by preset, and in the case of not replacing the fan, the input can be performed once initially, and the actual power needs to be obtained by the second terminal controller. It should be noted that the air volume of the whole system is the sum of the air volume of the first fan 3 and the air volume of the second fan 6, and in general, the air volume of the first fan 3 and the air volume of the second fan 6 can be kept equal, and in the case of dust accumulation of the heat pipe heat exchanger 2 and the like, the air volume of the first fan 3 or the second fan 6 can be adjusted slightly. After the air volume is adjusted, the heat exchange capacity of the heat pipe heat exchanger 2 changes, and the temperature of the output end of the condensing section of the heat pipe heat exchanger 2 is monitored by the second temperature sensor 12, that is, the temperature of the new air about to enter the OVEN furnace 4 is detected by the second temperature sensor 12, and then the power of the electric heating pipe in the OVEN furnace 4 is adjusted, for example, when the temperature of the new air about to enter the OVEN furnace 4 is relatively high, the power of the electric heating pipe can be reduced appropriately to reduce energy consumption, and when the temperature of the new air about to enter the OVEN furnace 4 is relatively low, the power of the electric heating pipe can be increased appropriately to meet the heat supply requirement. In this way, one cycle is completed, and if the power of the electric heating pipe after this cycle is not within the designed power range, the next cycle can be performed until the power of the electric heating pipe is maintained within the designed power range, so as to meet the requirements of energy saving and system safety.

[0077] Specifically, please refer to Figure 7 In an embodiment of the present application, the step of adjusting the air volume of the flue gas waste heat recovery system 100 according to the proportion of the actual power relative to the rated power specifically includes the following steps:

[0078] According to the proportion of the actual power relative to the rated power, the operation mode of the flue gas waste heat recovery system 100 is selected, wherein the operation mode includes three modes of normal mode, IDLE mode and DOWN mode.

[0079] selecting the normal mode when the actual power ≥ 70% rated power, selecting the IDLE mode when 30% rated power ≤ actual power < 70% rated power, and selecting the DOWN mode when the actual power < 30% rated power;

[0080] adjusting the actual air volume of the flue gas waste heat recovery system 100 according to the operation mode:

[0081] when the operation mode is the normal mode, adjusting the actual air volume of the flue gas waste heat recovery system 100 to be 100% rated air volume; when the operation mode is the IDLE mode, adjusting the actual air volume of the flue gas waste heat recovery system 100 to be 50% ~ 70% rated air volume; and when the operation mode is the DOWN mode, adjusting the actual air volume of the flue gas waste heat recovery system 100 to be 20% ~ 30% rated air volume.

[0082] In this embodiment, in order to match the energy consumption of the flue gas waste heat recovery system 100 with various working conditions in actual industrial production and ensure that the flue gas waste heat recovery system 100 can be safely, stably and reliably operated for a long time, the flue gas waste heat recovery system 100 of this embodiment is designed to have three operation modes, i.e., the normal mode, the IDLE mode and the DOWN mode. The normal mode corresponds to the most common production working condition in industrial production, at which time the industrial heat demand is large, so the power of the electric heating pipe is large, and correspondingly, the air volume demand in the system is large. The IDLE mode corresponds to the working condition when the equipment is on standby, preparing for short shutdown, or having low production demand, at which time the industrial heat demand is relatively low compared with the normal mode, so the power of the electric heating pipe is maintained in a relatively low range to ensure the basic process demand, and correspondingly, the air volume in the system is maintained in a relatively low range. The DOWN mode corresponds to the working condition when the equipment is long-term shutdown, maintenance and repair, or non-production period at night, at which time the industrial heat demand is the lowest or has no demand, and only the system anti-freezing or minimum circulation needs to be maintained, so the power of the electric heating pipe and the air volume in the system are maintained in the minimum range.

[0083] It should be noted that the actual power of the electric heating pipe can be calculated by monitoring the current signal of the electric heating pipe, and the current signal can be automatically collected by the first terminal controller or the second terminal controller at the power distribution cabinet of the OVEN furnace 4. The first terminal controller calculates the power of the electric heating pipe according to the current signal and adjusts the air speed of the first fan 3 accordingly to adjust the air volume of the first fan 3, and the second terminal controller calculates the power of the electric heating pipe according to the current signal and adjusts the air speed of the second fan 6 accordingly to adjust the air volume of the second fan 6, so as to adjust the total air volume in the whole system to match the power of the electric heating pipe.

[0084] Specifically, please refer to Figure 7In an embodiment of the present application, the set value of the inlet air temperature of the OVEN 4 is A℃-B℃, A

[0085] Obtaining the temperature value monitored by the second temperature sensor 12;

[0086] Determining the temperature value monitored by the second temperature sensor 12;

[0087] If the temperature value monitored by the second temperature sensor 12 is less than A, increasing the actual power of the electric heating pipe;

[0088] If the temperature value monitored by the second temperature sensor 12 is greater than B, decreasing the actual power of the electric heating pipe;

[0089] If A≤ the temperature value monitored by the second temperature sensor 12≤B, ending the adjustment.

[0090] In the embodiment, the set value of the inlet air temperature of the OVEN 4 is 180℃-190℃, after the air volume adjustment in the previous step, the heat exchange capacity of the heat pipe heat exchanger 2 changes, the temperature of the output end of the condensing section of the heat pipe heat exchanger 2 is monitored by the second temperature sensor 12, that is, the temperature of the new air about to enter the OVEN 4 is detected by the second temperature sensor 12, and then the power of the electric heating pipe in the OVEN 4 is adjusted, for example, when the temperature of the new air about to enter the OVEN 4 is high (>190℃), the power of the electric heating pipe can be appropriately reduced to reduce energy consumption, when the temperature of the new air about to enter the OVEN 4 is low (<180℃), in order to meet the requirements of industrial production, the power of the electric heating pipe can be appropriately increased to meet the heat supply. In this way, one cycle is completed, if the power of the electric heating pipe after the current cycle is not within the designed power range, the next cycle can be performed until the power of the electric heating pipe is maintained within the designed power range, to meet the requirements of energy saving and system safety.

[0091] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, any equivalent structural transformation made according to the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A flue gas heat recovery system, characterized by, The flue gas waste heat recovery system comprises a first filter (1), a heat pipe heat exchanger (2), a first fan (3), an OVEN furnace (4), a second filter (5), a second fan (6), an air supply pipeline (7) and an exhaust air main pipeline (8); The air supply pipeline (7) is sequentially connected with the first filter (1), a condensation section of the heat pipe heat exchanger (2), the first fan (3) and an air inlet end of the OVEN furnace (4); The exhaust air main pipeline (8) is sequentially connected with an air outlet end of the OVEN furnace (4), the second filter (5), an evaporation section of the heat pipe heat exchanger (2) and the second fan (6); The flue gas waste heat recovery system further comprises a regulation and control system, the regulation and control system comprises a first terminal controller and a second terminal controller, and an electric heating pipe is arranged in the OVEN furnace (4); The first terminal controller and the second terminal controller are connected with the electric heating pipe and are used for monitoring actual power of the electric heating pipe; The first terminal controller is connected with the first fan (3) and is used for controlling a rotating speed of the first fan (3), and the second terminal controller is connected with the second fan (6) and is used for controlling a rotating speed of the second fan (6); The regulation and control system further comprises a first temperature sensor (11), a second temperature sensor (12), a third temperature sensor (13) and a fourth temperature sensor (14); The first temperature sensor (11) is arranged at an input end of the condensation section of the heat pipe heat exchanger (2), the second temperature sensor (12) is arranged at an output end of the condensation section of the heat pipe heat exchanger (2), and the first temperature sensor (11) and the second temperature sensor (12) are in communication connection with the first terminal controller; The third temperature sensor (13) is arranged at an input end of the evaporation section of the heat pipe heat exchanger (2), the fourth temperature sensor (14) is arranged at an output end of the evaporation section of the heat pipe heat exchanger (2), and the third temperature sensor (13) and the fourth temperature sensor (14) are in communication connection with the second terminal controller.

2. The flue gas heat recovery system of claim 1, wherein, The heat pipe heat exchanger (2) comprises a high-temperature heat exchange module (2A), a high-medium-temperature combined heat exchange module (2B) and a communication pipe (2C); A first air supply pipe (21) and a first exhaust air pipe (22) are arranged in the high-temperature heat exchange module (2A), the first air supply pipe (21) is located at a condensation section of the high-temperature heat exchange module (2A) and is connected with the air supply pipeline (7), and the first exhaust air pipe (22) is located at an evaporation section of the high-temperature heat exchange module (2A) and is connected with the exhaust air main pipeline (8); In addition, a second air supply pipe (21) and a second exhaust air pipe (22) are arranged in the high-medium-temperature combined heat exchange module (2B), the second air supply pipe (21) is located at a condensation section of the high-medium-temperature combined heat exchange module (2B) and is connected with the air supply pipeline (7), and the second exhaust air pipe (22) is located at an evaporation section of the high-medium-temperature combined heat exchange module (2B) and is connected with the exhaust air main pipeline (8); One of the communication pipes (2C) connects the air supply pipe (21) in the high-temperature heat exchange module (2A) with the air supply pipe (21) in the high-mid-temperature combined heat exchange module (2B), and the other communication pipe (2C) connects the air exhaust pipe (22) in the high-temperature heat exchange module (2A) with the air exhaust pipe (22) in the high-mid-temperature combined heat exchange module (2B); Wherein, the high-temperature heat exchange module (2A) and the high-mid-temperature combined heat exchange module (2B) are both provided with heat exchange pipes (23), one end of the heat exchange pipe (23) penetrates into the air supply pipe (21), the other end of the heat exchange pipe (23) penetrates into the air exhaust pipe (22), the outer wall of the heat exchange pipe (23) located in the air supply pipe (21) is provided with a heat dissipation fin (233), and the heat exchange pipe (23) forms a steam cavity (23a) therein, and the steam cavity (23a) contains a heat exchange working medium.

3. The flue gas heat recovery system of claim 1, wherein, The flue gas waste heat recovery system further comprises a first differential pressure gauge (9) and a cleaning device, the first differential pressure gauge (9) is connected in parallel with the evaporation section of the heat pipe heat exchanger (2) and is used for monitoring the pressure difference of the evaporation section of the heat pipe heat exchanger (2), and the cleaning device is connected with the evaporation section of the heat pipe heat exchanger (2), and the first differential pressure gauge (9) is in communication connection with the cleaning device; And / or, the flue gas waste heat recovery system further comprises a second differential pressure gauge, the second differential pressure gauge is arranged in parallel with the second filter (5) and is used for monitoring the pressure difference of the second filter (5).

4. The flue gas heat recovery system according to any one of claims 1 to 3, wherein The air supply pipeline (7) is provided with a first valve (71), and the first valve (71) is located between the first fan (3) and the OVEN furnace (4); The air exhaust main pipeline (8) is provided with a second valve (81) and a third valve (82), the second valve (81) is located between the OVEN furnace (4) and the second filter (5), and the third valve (82) is located between the heat pipe heat exchanger (2) and the second fan (6).

5. The flue gas heat recovery system according to any one of claims 1 to 3, wherein The flue gas waste heat recovery system further comprises an air exhaust branch pipeline (15), one end of the air exhaust branch pipeline (15) is connected with the air outlet end of the OVEN furnace (4), the other end of the air exhaust branch pipeline (15) is connected with the second fan (6), and the air exhaust branch pipeline (15) is provided with a fourth valve (151).

6. A control method of a flue gas waste heat recovery system, implemented based on the flue gas waste heat recovery system as claimed in claim 1, characterized in that, The control method of the flue gas waste heat recovery system comprises the following steps: Obtaining the actual power and the rated power of the electric heating pipe; Adjusting the actual air volume of the flue gas waste heat recovery system according to the proportion of the actual power to the rated power; Adjusting the actual power of the electric heating pipe according to the temperature value monitored by the second temperature sensor (12).

7. The control method of the flue gas waste heat recovery system according to claim 6, characterized by, The step of adjusting the air volume of the flue gas waste heat recovery system according to the proportion of the actual power to the rated power specifically comprises the following steps: Selecting the operation mode of the flue gas waste heat recovery system according to the proportion of the actual power to the rated power, wherein the operation mode includes normal mode, IDLE mode and DOWN mode; The normal mode is selected when the actual power is greater than or equal to 70% of the rated power, the IDLE mode is selected when the actual power is between 30% of the rated power and 70% of the rated power, and the DOWN mode is selected when the actual power is less than 30% of the rated power; The actual air volume of the flue gas waste heat recovery system is adjusted according to the operation mode: When the operation mode is the normal mode, the actual air volume of the flue gas waste heat recovery system is adjusted to 100% of the rated air volume; when the operation mode is the IDLE mode, the actual air volume of the flue gas waste heat recovery system is adjusted to 50%-70% of the rated air volume; and when the operation mode is the DOWN mode, the actual air volume of the flue gas waste heat recovery system is adjusted to 20%-30% of the rated air volume.

8. The control method of the flue gas waste heat recovery system according to any one of claims 6 to 7, characterized by, The set value of the inlet air temperature of the OVEN furnace (4) is A℃-B℃, and A<B; The step of adjusting the actual power of the electric heating pipe according to the temperature value monitored by the second temperature sensor (12) specifically comprises the following steps: obtaining the temperature value monitored by the second temperature sensor (12); judging the size of the temperature value monitored by the second temperature sensor (12); if the temperature value monitored by the second temperature sensor (12) is less than A, increasing the actual power of the electric heating pipe; if the temperature value monitored by the second temperature sensor (12) is greater than B, reducing the actual power of the electric heating pipe; if A is less than or equal to the temperature value monitored by the second temperature sensor (12) and B is greater than or equal to the temperature value monitored by the second temperature sensor (12), ending the adjustment.

Images