A dedicated test bench for air preheaters

Abstract

This invention proposes a dedicated test bench for air preheaters, relating to the field of air preheater technology. The dedicated test bench includes a flue gas circulation pipeline, a preheated gas circulation pipeline, a heat exchange circulation pipeline, a heat exchanger, a liquid-gas separator, and a flue gas component additive. The flue gas circulation pipeline includes an inlet pipe and an outlet pipe; the preheated gas circulation pipeline includes an inlet pipe and an outlet pipe; and the heat exchange circulation pipeline includes a liquid inlet pipe and a liquid outlet pipe. The inlet and outlet of the heat exchanger are connected to the gas inlet and outlet of the air preheater via the inlet and outlet pipes. The liquid outlet of the liquid-gas separator is connected to the liquid inlet of the heat exchanger via the liquid inlet pipe, and the liquid outlet of the heat exchanger is connected to the mixed liquid inlet of the liquid-gas separator via the liquid outlet pipe. The inlet pipe connects the outlet of the liquid-gas separator to the flue gas inlet of the air preheater, and the outlet pipe connects the flue gas outlet of the air preheater to the liquid inlet pipe. The flue gas component additive is connected in series in the inlet pipe. This invention enables closed-loop circulation and heat recovery of flue gas and preheated gas, and can precisely control the inlet temperature.

Description

Technical Field

[0001] This invention relates to the field of air preheater technology, and more specifically, to a dedicated test bench for air preheaters. Background Technology

[0002] Air preheaters are core heat exchange equipment in thermal power generation, industrial boilers, and waste heat recovery systems. They utilize the high-temperature flue gas discharged from the boiler to heat the combustion air (usually called secondary air) entering the furnace, thereby reducing the flue gas temperature, improving boiler thermal efficiency, and reducing fuel consumption. Air preheaters operate in harsh environments characterized by high temperatures, dust, corrosive gases (such as SO2, SO3, and water vapor), and are prone to ash accumulation and low-temperature corrosion. Their heat exchange efficiency, resistance characteristics, sealing performance, and material durability directly affect the safety and economy of the entire system.

[0003] During the product development, factory inspection, and evaluation of air preheaters, a dedicated test bench needs to be designed to simulate actual operating conditions and test the comprehensive performance of the air preheater. Various test apparatuses for air preheaters or similar heat exchangers have been disclosed in the existing technology, such as: First, most existing test benches can only perform single heat exchange tests on the flue gas side or the air side, and cannot achieve dual recycling of flue gas and preheated gas, resulting in high consumption of test media, high operating costs, and difficulty in conducting long-term continuous aging tests.

[0004] Secondly, traditional test benches mostly use electric heating tubes or steam heating to heat the flue gas separately, while the secondary air is cooled separately by introducing ambient air with a fan or water cooling. This method not only fails to achieve heat exchange between the flue gas and the secondary air, but also has a slow heating and cooling response and high energy consumption.

[0005] Third, the flue gas at the air preheater inlet contains varying concentrations of corrosive gases and moisture. Existing test benches typically use burners to generate flue gas, whose composition is fixed, making it difficult to simulate the flue gas composition under different fuel types (such as coal, biomass, and waste). More importantly, after passing through the air preheater, the composition of the flue gas changes due to physicochemical reactions with the heat storage elements within the air preheater (such as corrosion from acidic gases and adsorption by ash accumulation). Directly discharging or simply treating the used flue gas before discharging not only wastes thermal energy but also prevents cyclic testing; if it is directly fed back into the air preheater, the test results will deviate from reality due to compositional distortion.

[0006] To address the aforementioned shortcomings, there is an urgent need for a dedicated air preheater test bench that can achieve closed-loop recycling of flue gas and preheated gas, possess flue gas composition adjustment and purification functions, and control the inlet temperatures of flue gas and preheated gas. This would allow for a realistic, efficient, and economical simulation of the air preheater's performance under various operating conditions. Summary of the Invention The purpose of this invention is to provide a dedicated test bench for air preheaters, which can realize closed-loop recycling and heat exchange and recovery of experimental flue gas and experimental preheated gas, has flue gas composition adjustment and purification functions, and can accurately control the inlet temperature of flue gas and preheated gas.

[0007] The embodiments of the present invention are implemented as follows: This application provides a dedicated test bench for air preheaters, including: A flue gas recirculation pipeline, comprising an inlet pipe and an outlet pipe; A preheating gas circulation pipeline, the preheating gas circulation pipeline including an inlet pipeline and an outlet pipeline; A heat exchange circulation pipeline, wherein the heat exchange circulation pipeline includes an inlet pipeline and an outlet pipeline; A heat exchanger is provided with an air inlet, an air outlet, a liquid inlet, and a liquid outlet. One end of the air inlet pipe is connected to the air inlet, and the other end is connected to the gas inlet of the air preheater. One end of the air outlet pipe is connected to the air outlet, and the other end is connected to the gas outlet of the air preheater. The liquid-gas separator includes a gas outlet, a liquid outlet, and a mixed liquid inlet. One end of the liquid inlet pipe is connected to the liquid inlet, and the other end is connected to the liquid outlet. One end of the liquid outlet pipe is connected to the liquid outlet, and the other end is connected to the mixed liquid inlet. One end of the flue gas inlet pipe is connected to the gas outlet end, and the other end is connected to the flue gas inlet end of the air preheater. One end of the flue gas outlet pipe is connected to the liquid inlet pipe, and the other end is connected to the flue gas outlet end of the air preheater. A flue gas component adder is connected in series in the flue gas inlet pipe.

[0008] In some embodiments of the present invention, temperature compensators are provided on both the smoke inlet pipe and the air inlet pipe.

[0009] In some embodiments of the present invention, the above-mentioned smoke inlet pipe and the air inlet pipe share the same temperature compensator. The temperature compensator includes a heat exchange body, a semiconductor refrigeration chip, and two heat storage devices. The semiconductor refrigeration chip is disposed on the heat exchange body and divides the heat exchange body into a first heat-conducting part and a second heat-conducting part. A smoke inlet channel is opened on the first heat-conducting part and is connected in series with the smoke inlet pipe. An air inlet channel is opened on the second heat-conducting part and is connected in series with the air inlet pipe. One of the heat storage devices is disposed on the first heat-conducting part, and the other heat storage device is disposed on the second heat-conducting part. The heating surface of the semiconductor refrigeration chip faces the first heat-conducting part, and the cooling surface of the semiconductor refrigeration chip faces the second heat-conducting part.

[0010] In some embodiments of the present invention, a first temperature sensor is provided on the smoke inlet pipe, the first temperature sensor being located at the inlet end of the smoke inlet channel; a second temperature sensor is provided on the air inlet pipe, the second temperature sensor being located at the inlet end of the air inlet channel; the semiconductor cooling chip is connected to a temperature control module, the temperature control module being connected to the first temperature sensor and the second temperature sensor respectively.

[0011] In some embodiments of the present invention, a dehumidification module is connected in series on the above-mentioned flue gas inlet pipe, and the dehumidification module is located between the liquid-gas separator and the flue gas component adder.

[0012] In some embodiments of the present invention, a filter module is connected in series on both the liquid inlet pipe and the liquid outlet pipe, and the two filter modules are respectively located on the liquid inlet side and the liquid outlet side.

[0013] In some embodiments of the present invention, the above-mentioned smoke outlet pipeline and the liquid outlet pipeline are connected by a liquid-gas mixing module, which is located between the liquid inlet end side and the filter module corresponding to the liquid inlet end side.

[0014] In some embodiments of the present invention, a delivery pump is connected in series on the liquid inlet pipe, the gas outlet pipe, and the smoke outlet pipe.

[0015] In some embodiments of the present invention, a first check valve is connected in series on the smoke outlet pipe, and a second check valve is connected in series on the smoke inlet pipe.

[0016] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: 1. This application, by setting up flue gas circulation pipelines, preheated gas circulation pipelines, and heat exchange circulation pipelines, and by coupling them with a liquid-gas separator and a heat exchanger, allows the flue gas to return to the system and participate in the test again after passing through the air preheater, and the preheated gas can also be recycled. This eliminates the need for continuous exhaust and replenishment of flue gas and preheated gas, reducing the consumption of test media and making it suitable for performance testing of air preheaters operating continuously for extended periods.

[0017] 2. In this application, one end of the flue gas outlet pipe is directly connected to the liquid inlet pipe, allowing the low-temperature flue gas discharged from the air preheater to fully mix with the heat exchange liquid. On the one hand, the heat exchange liquid can absorb dust, new products generated after corrosion, and other components in the flue gas that do not meet the test conditions, preventing harmful substances from accumulating in the circulation and affecting the test accuracy. On the other hand, the heat exchange liquid exchanges heat with the flue gas, initially raising the temperature of the flue gas and preheating the gas for initial cooling, thereby reducing the energy consumption of the subsequent temperature compensation device.

[0018] 3. The preheated gas undergoes indirect heat exchange with the flue gas through a heat exchanger, which can achieve the cooling of the preheated gas and the initial heating of the flue gas. At the same time, in conjunction with the subsequent temperature compensator, the preheated gas is cooled a second time and the flue gas is heated a second time. This allows for precise control of the temperature of the preheated gas and flue gas before they enter the air preheater, as well as the temperature regulation response speed.

[0019] 4. A flue gas component additive is connected in series on the flue gas inlet pipe. It can add specific gas components to the circulating flue gas in a quantitative manner according to different fuel types or different corrosion conditions, so that the flue gas composition entering the air preheater is highly consistent with the actual operating conditions, thereby improving the reliability and universality of the test results. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of a three-dimensional structure in one direction according to an embodiment of the present invention; Figure 4 This is a three-dimensional structural diagram of an embodiment of the present invention from another direction; Figure 5 This is a schematic diagram of the structure of the tubular heat exchanger body in an embodiment of the present invention.

[0022] Icons: 1-Inlet flue; 2-Outlet flue; 3-Outlet gas; 4-Inlet gas; 5-Inlet liquid; 6-Outlet liquid; 7-Heat exchanger; 8-Inlet gas; 9-Outlet gas; 10-Inlet liquid; 11-Outlet liquid; 12-Tube heat exchanger body; 13-Shell; 14-Heat exchange tube; 15-Compressor; 16-Expansion valve; 17-Liquid-gas separator; 18-Outlet gas; 19-Outlet liquid; 20-Mixed liquid inlet Inlet end; 21-Flue gas component adder; 22-First heat conduction part; 23-Second heat conduction part; 24-Semiconductor cooling chip; 25-Heat storage device; 26-Flue gas inlet channel; 27-Air inlet channel; 28-First temperature sensor; 29-Second temperature sensor; 30-Dehumidification module; 31-Liquid-gas mixing module; 32-Transfer pump; 33-First one-way valve; 34-Second one-way valve; 35-Filter module; 36-Air preheater. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] Example Please refer to Figures 1-5 This embodiment provides a dedicated test bench for an air preheater, including a flue gas circulation pipeline, a preheating gas circulation pipeline, a heat exchange circulation pipeline, a heat exchanger 7, a liquid-gas separator 17, and a flue gas component additive 21. The flue gas circulation pipeline includes an inlet pipe 1 and an outlet pipe 2. The preheating gas circulation pipeline includes an inlet pipe 4 and an outlet pipe 3. The heat exchange circulation pipeline includes a liquid inlet pipe 5 and an outlet pipe 6. The heat exchanger 7 is equipped with an inlet 8, an outlet 9, a liquid inlet 10, and an outlet 11. One end of the inlet pipe 4 is connected to the inlet 8, and the other end is connected to the gas inlet of the air preheater. One end of the outlet pipe 3 is connected to the outlet 9, and the other end is connected to the gas outlet of the air preheater. The liquid-gas separator 17 includes an outlet 18, an outlet 19, and a mixed liquid inlet 20. One end of the inlet pipe 5 is connected to the inlet 10, and the other end is connected to the outlet 19. One end of the liquid outlet pipe 6 is connected to the liquid outlet 11, and the other end is connected to the mixed liquid inlet 20. One end of the flue gas inlet pipe 1 is connected to the gas outlet 18, and the other end is connected to the flue gas inlet of the air preheater. One end of the flue gas outlet pipe 2 is connected to the liquid inlet pipe 5, and the other end is connected to the flue gas outlet of the air preheater. The flue gas component additive 21 is connected in series with the flue gas inlet pipe 1.

[0026] The working principle of this embodiment is as follows: First, the preheated gas, after heat exchange in the air preheater, enters heat exchanger 7 and is compressed into a high-temperature, high-pressure state. The heat exchange liquid in the liquid-gas separator 17 flows out from its outlet 19, enters the inlet 10 of the heat exchanger 7 through the inlet pipe 5, and flows through the interior of the heat exchanger 7 to exchange heat with the preheated gas in a high-temperature, high-pressure state. After the temperature of the heat exchange liquid rises, it is discharged from the outlet 11 of the heat exchanger 7 and then returns to the mixed liquid inlet 20 of the liquid-gas separator 17 through the outlet pipe 6. This forms a closed-loop circulation loop for the heat exchange liquid.

[0027] Then, the preheated gas (secondary air in this embodiment) is compressed inside the heat exchanger 7 and exchanges heat with the heat exchange fluid. After the above heat exchange, the preheated gas is formed at a medium temperature and high pressure. After the gas expands and decompresses in the heat exchanger 7, it becomes a low temperature and normal pressure preheated gas. Finally, it flows out from the air inlet 8 of the heat exchanger 7 and enters the gas inlet end of the air preheater through the air inlet pipe 4. Inside the air preheater, the preheated gas cross-exchanges heat with the flue gas, and then is discharged from the gas outlet end of the air preheater. It returns to the air outlet 9 of the heat exchanger 7 through the air outlet pipe 3 and re-enters the heat exchanger 7 to participate in the next round of heat exchange. This cycle continues, and the temperature of the preheated gas is continuously adjusted and sent into the air preheater.

[0028] Subsequently, the flue gas discharged from the air preheater flows out from its outlet end and directly merges into the liquid inlet pipe 5 via the outlet pipe 2. In the liquid inlet pipe 5, the flue gas and the flowing heat exchange liquid are fully mixed and undergo direct contact heat exchange. During the above process, some corrosive components and dust in the flue gas are absorbed by the heat exchange liquid, while the flue gas is initially heated by the heat exchange liquid. The mixed gas-liquid two-phase medium continues to flow with the heat exchange liquid, and after passing through the liquid-gas separator 17, the gas-liquid mixture is separated back into flue gas and heat exchange liquid. The separated heat exchange liquid enters the liquid inlet pipe 5 from the outlet end 19, and finally enters the heat exchanger 7 to exchange heat with the preheated gas, re-participating in the heat exchange liquid circulation; the separated flue gas enters the outlet pipe 1 from the outlet end 18, and can re-enter the air preheater after passing through the outlet pipe 1.

[0029] In the above process, by setting up flue gas circulation pipelines, preheated gas circulation pipelines, and heat exchange circulation pipelines, and through the coupling connection of liquid-gas separator 17 and heat exchanger 7, the flue gas can return to the system to participate in the test after passing through the air preheater, and the preheated gas can also be recycled. There is no need for continuous exhaust and replenishment of flue gas and preheated gas, which reduces the consumption of test media and is suitable for performance tests of air preheaters that operate continuously for a long time.

[0030] In this embodiment, one end of the flue gas outlet pipe 2 is directly connected to the liquid inlet pipe 5, allowing the low-temperature flue gas discharged from the air preheater to fully mix with the heat exchange liquid. On the one hand, the heat exchange liquid can absorb dust, new products generated after corrosion, and other components in the flue gas that do not meet the test conditions, preventing harmful substances from accumulating in the circulation and affecting the test accuracy. On the other hand, the heat exchange liquid exchanges heat with the flue gas, initially raising the temperature of the flue gas and preheating the gas for initial cooling, thereby reducing the energy consumption of the subsequent temperature compensation device.

[0031] It is worth noting that the preheated gas undergoes indirect heat exchange with the flue gas through heat exchanger 7, which can achieve the cooling of the preheated gas and the initial heating of the flue gas. At the same time, in conjunction with the subsequent temperature compensator, the preheated gas is cooled a second time and the flue gas is heated a second time, which can accurately control the temperature of the preheated gas and the flue gas before they enter the air preheater, as well as the temperature regulation response speed.

[0032] Furthermore, in the above process, a flue gas component additive 21 is connected in series on the flue gas inlet pipe 1. When the separated gas flows through the flue gas component additive 21, the required gas components can be introduced in a specified proportion to simulate the flue gas composition under test conditions. The adjusted flue gas enters the flue gas inlet of the air preheater through the flue gas inlet pipe 1, where it exchanges heat with the preheated gas again. This completes the closed-loop recycling of the flue gas. The flue gas component additive 21 connected in series on the flue gas inlet pipe 1 can quantitatively add specific gas components to the circulating flue gas according to different fuel types or different corrosion conditions, ensuring that the flue gas composition entering the air preheater closely matches the actual operating conditions, thus improving the reliability and universality of the test results.

[0033] Furthermore, in some embodiments of this example, temperature compensators are provided on both the flue gas inlet pipe 1 and the air inlet pipe 4. During the test, heat loss occurs in the flue gas and preheated gas, causing them to fail to reach the predetermined temperature for entering the air preheater. Therefore, the temperature compensator can adjust the temperature of the flue gas and preheated gas to achieve the predetermined temperature.

[0034] Specifically, in this embodiment, the smoke inlet pipe 1 and the air inlet pipe 4 share the same temperature compensator, which includes a heat exchange body, a thermoelectric cooler 24, and two heat storage tanks 25. The thermoelectric cooler 24 is disposed on the heat exchange body, dividing the heat exchange body into a first heat-conducting section 22 and a second heat-conducting section 23. A smoke inlet channel 26 is formed on the first heat-conducting section 22 and is connected in series with the smoke inlet pipe 1. An air inlet channel 27 is formed on the second heat-conducting section 23 and is connected in series with the air inlet pipe 4. One heat storage tank 25 is disposed on the first heat-conducting section 22, and the other heat storage tank 25 is disposed on the second heat-conducting section 23. The heating surface of the thermoelectric cooler 24 faces the first heat-conducting section 22, and the cooling surface of the thermoelectric cooler 24 faces the second heat-conducting section 23.

[0035] The heating surface of the aforementioned semiconductor cooling chip 24 faces the first heat-conducting part 22, allowing it to exchange heat with the flue gas in the flue gas inlet channel 26. The cooling surface faces the second heat-conducting part 23, allowing it to exchange heat with the preheated gas in the air inlet channel 27. In actual operation, the flue gas needs to be heated to increase its temperature, and the preheated gas needs to be cooled to decrease its temperature.

[0036] When energized, the semiconductor cooling chip 24 generates heat on one side and absorbs heat on the other. The generated heat is used to heat the flue gas, and the absorbed heat is used to cool the preheated gas. In this way, there is no need to set up separate heaters and coolers, avoiding the energy waste of independent heating and cooling in traditional solutions, and significantly improving overall energy efficiency.

[0037] Furthermore, the heat exchange efficiency of the aforementioned semiconductor cooling chip 24 is constant. This means that if it directly exchanges heat with the preheated gas and flue gas, the compensated temperature difference will be essentially the same. However, the temperature rise of the flue gas and the temperature drop of the preheated gas will not be the same. Therefore, in this embodiment, both the first heat-conducting part 22 and the second heat-conducting part 23 are equipped with heat storage devices 25. The heat storage devices 25 can absorb or release heat. Essentially, if the semiconductor cooling chip 24 generates excessive heat on the flue gas side, it can temporarily store it in the corresponding heat storage device 25. Conversely, if it absorbs excessive heat on the preheated gas side, the corresponding heat storage device 25 will release more heat to accommodate more of the cooling surface's heat absorption. This effectively maintains the stability of the flue gas and preheated gas temperatures, preventing inaccurate temperature regulation of the flue gas and preheater. Using the semiconductor cooling chip 24 as a temperature compensator to achieve shared use of the same temperature compensator also has advantages such as compact structure, reduced heat transfer distance, and greater energy efficiency.

[0038] In addition to the effects mentioned above, the semiconductor cooling chip 24 used in this embodiment can also make full use of the temperature difference between the flue gas and the preheated gas, reducing the external energy input. The semiconductor cooling chip 24 utilizes the Peltier effect to actively pump the heat from the preheated gas side to the flue gas side, essentially transferring the excess heat from the preheated gas to the flue gas for use, further reducing the energy consumption required for auxiliary heating.

[0039] It should be noted that in this embodiment, the heat storage device 25 uses a phase change material. Phase change materials have the ability to change their physical state within a certain temperature range. When heated by the semiconductor refrigeration chip 24 on the flue gas side, the phase change material absorbs and stores a large amount of latent heat; when cooled by the semiconductor refrigeration chip 24 on the preheated gas side, the corresponding phase change material releases heat, which is absorbed by the cooling surface of the semiconductor refrigeration chip 24. These processes occur simultaneously. The temperature of the phase change material itself remains almost constant before the phase change is complete, forming a wide temperature plateau. Although the temperature remains constant, the absorbed or released latent heat is considerable. Therefore, its temperature remains constant while absorbing or releasing a large amount of heat. It can stably exchange heat with the flue gas or preheated gas, ensuring that the temperature of the flue gas or preheated gas always stably reaches the predetermined temperature.

[0040] Preferably, in this embodiment, a first temperature sensor 28 is provided on the smoke inlet pipe 1. The first temperature sensor 28 is located at the inlet end of the smoke inlet channel 26, and a second temperature sensor 29 is provided on the air inlet pipe 4. The second temperature sensor 29 is located at the inlet end of the air inlet channel 27, and a temperature control module is connected to the semiconductor cooling chip 24. The temperature control module is connected to the first temperature sensor 28 and the second temperature sensor 29 respectively.

[0041] When the first temperature sensor 28 detects that the temperature of the flue gas entering the flue gas inlet channel 26 is lower or higher than a preset value, or when the second temperature sensor 29 detects that the temperature of the preheated gas entering the air inlet channel 27 is higher or lower than a preset value, it indicates that the power of the aforementioned thermoelectric cooler 24 is too low or too high. At this time, the phase change material is unable to continue its phase change or the phase change process has become saturated, and the temperature regulation capability of the phase change material changes. At this time, the temperature control module adjusts the working power of the thermoelectric cooler 24 according to the preset program. When the phase change material is unable to continue its phase change, the heat pumping efficiency of the thermoelectric cooler 24 is increased, transferring more heat from the preheated gas side to the flue gas side, and quickly adjusting the temperature on both sides back to the preset range; conversely, when the phase change material is saturated, the temperature control module can reduce the working power of the thermoelectric cooler 24 to reduce the amount of heat transferred. In this way, the inlet temperature on both sides can be effectively maintained to ensure that the operating conditions always meet the preset test requirements during the performance test of the air preheater.

[0042] Preferably, in this embodiment, a dehumidification module 30 is connected in series on the aforementioned flue gas inlet pipe 1. The dehumidification module 30 is located between the liquid-gas separator 17 and the flue gas component adder 21. After the flue gas passes through the liquid-gas separator 17 to separate liquid water, it may still carry some gaseous water vapor. If this is not further removed, it will change the humidity parameters of the flue gas, interfere with the detection and control of flue gas component concentration, and thus affect the accuracy of the air preheater performance test results. The aforementioned dehumidification module 30 can effectively remove moisture from the flue gas to ensure stable testing. The aforementioned dehumidification module 30 is an existing structure and will not be described further here. If anything is unclear, please refer to the prior art.

[0043] Preferably, in this embodiment, a filter module 35 is connected in series on both the inlet pipe 5 and the outlet pipe 6. The two filter modules 35 are located at the inlet end and the outlet end of the mixed liquid, respectively. The heat exchange liquid containing impurities is filtered out by the filter module 35 on the outlet pipe 6 before entering the heat exchanger 7 to re-enter the circulation, avoiding the accumulation and blockage of impurities in the pipes or channels, ensuring the heat exchange effect of the heat exchanger 7, and also preventing impurities from scratching and damaging the components of the heat exchanger 7, maintaining the long-term stable operation of the test bench, and ensuring the reliability of the test process. Similarly, the filter module 35 is also an existing structure, which will not be described further here. If there is any unclear point, please refer to the prior art.

[0044] Furthermore, in this embodiment, the flue gas outlet pipe 2 and the liquid outlet pipe 6 are connected by a liquid-gas mixing module 31, which is located between the liquid inlet end and the corresponding filter module 35. After the flue gas flows out of the dehumidification module 30, it can be fully mixed with the heat exchange liquid in the pipe through the liquid-gas mixing module 31 to improve the heat exchange efficiency and the effect of collecting dust and new products generated by corrosion in the flue gas.

[0045] Preferably, in this embodiment, a transfer pump 32 is connected in series on the liquid inlet pipe 5, the gas outlet pipe 3, and the flue gas outlet pipe 2. The transfer pump 32 is used to provide power for the flow of the medium in the corresponding pipe, ensuring that the heat exchange liquid and flue gas can be stably circulated and transported according to the preset route. By configuring independent transfer pumps 32 in different pipes, the flow rate and pressure of the medium in each pipe can be adjusted according to the actual test requirements, thereby adapting to the test requirements under different working conditions and obtaining more comprehensive and accurate test data.

[0046] Preferably, in this embodiment, a first one-way valve 33 is connected in series on the flue gas outlet pipe 2, and a second one-way valve 34 is connected in series on the flue gas inlet pipe 1. The first one-way valve 33 can prevent the heat exchange liquid in the liquid outlet pipe 6 from flowing back along the flue gas outlet pipe 2, and the second one-way valve 34 can prevent the heat exchange liquid from entering the flue gas outlet pipe 2. The two valves working together can effectively avoid the impact of heat exchange liquid overflow under different operating conditions, ensure test accuracy, and improve the stability of the entire test bench operation and the reliability of test data.

[0047] It is worth noting that the heat exchanger 7 in this embodiment includes a tubular heat exchanger body 12, a compressor 15, and an expansion valve 16 connected in series. The preheated gas, after heat exchange in the pre-air conditioner, first enters the compressor 15 and is compressed to form a high-temperature, high-pressure state. Then, the gas enters the heat exchange tubes 14 within the tubular heat exchanger body 12. The heat exchange liquid inside the shell 13 of the tubular heat exchanger body 12 undergoes indirect heat exchange with the preheated gas in the heat exchange tubes 14, ultimately forming a medium-temperature, high-pressure preheated gas. The preheated gas then exits the heat exchange tubes 14 and enters the expansion valve 16. After passing through the expansion valve 16, the preheated gas reaches a low-temperature, normal-pressure state. During the above process, the inlet pipe 5 and the outlet pipe 6 are connected to the interior of the shell 13 of the tubular heat exchanger body 12. The heat exchange liquid enters the shell 13 along the inlet pipe 5, exchanges heat with the preheated gas in the heat exchange tubes 14, and then exits along the outlet pipe 6. The compressor 15 has an air inlet 8 at its inlet and an expansion valve 16 has an air outlet 9 at its outlet. The housing 13 is provided with a liquid inlet 10 and a liquid outlet 11, which are used to connect to the liquid inlet pipe 5 and the liquid outlet pipe 6, respectively.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dedicated test bench for air preheaters, characterized in that, include: A flue gas recirculation pipeline, comprising an inlet pipe and an outlet pipe; A preheating gas circulation pipeline, the preheating gas circulation pipeline including an inlet pipeline and an outlet pipeline; A heat exchange circulation pipeline, wherein the heat exchange circulation pipeline includes an inlet pipeline and an outlet pipeline; A heat exchanger is provided with an air inlet, an air outlet, a liquid inlet, and a liquid outlet. One end of the air inlet pipe is connected to the air inlet, and the other end is connected to the gas inlet of the air preheater. One end of the air outlet pipe is connected to the air outlet, and the other end is connected to the gas outlet of the air preheater. The liquid-gas separator includes a gas outlet, a liquid outlet, and a mixed liquid inlet. One end of the liquid inlet pipe is connected to the liquid inlet, and the other end is connected to the liquid outlet. One end of the liquid outlet pipe is connected to the liquid outlet, and the other end is connected to the mixed liquid inlet. One end of the flue gas inlet pipe is connected to the gas outlet end, and the other end is connected to the flue gas inlet end of the air preheater. One end of the flue gas outlet pipe is connected to the liquid inlet pipe, and the other end is connected to the flue gas outlet end of the air preheater. A flue gas component adder is connected in series in the flue gas inlet pipe.

2. The air preheater dedicated test bench according to claim 1, characterized in that, Temperature compensators are installed on both the smoke inlet pipe and the air inlet pipe.

3. The air preheater dedicated test bench according to claim 2, characterized in that, The smoke inlet pipe and the air inlet pipe share the same temperature compensator. The temperature compensator includes a heat exchange body, a thermoelectric cooler, and two heat storage units. The thermoelectric cooler is disposed on the heat exchange body, dividing the heat exchange body into a first heat-conducting part and a second heat-conducting part. A smoke inlet channel is provided on the first heat-conducting part and is connected in series with the smoke inlet pipe. An air inlet channel is provided on the second heat-conducting part and is connected in series with the air inlet pipe. One of the heat storage units is disposed on the first heat-conducting part, and the other heat storage unit is disposed on the second heat-conducting part. The heating surface of the thermoelectric cooler faces the first heat-conducting part, and the cooling surface of the thermoelectric cooler faces the second heat-conducting part.

4. The air preheater dedicated test bench according to claim 3, characterized in that, A first temperature sensor is installed on the smoke inlet pipe, located at the inlet end of the smoke inlet channel. A second temperature sensor is installed on the air inlet pipe, located at the inlet end of the air inlet channel. A temperature control module is connected to the semiconductor cooling chip, and the temperature control module is connected to both the first and second temperature sensors.

5. The dedicated test bench for air preheaters according to claim 1, characterized in that, A dehumidification module is connected in series on the flue gas inlet pipe, and the dehumidification module is located between the liquid-gas separator and the flue gas component additive.

6. The dedicated test bench for air preheaters according to claim 1, characterized in that, Both the inlet and outlet pipes are connected in series with a filter module, and the two filter modules are located at the inlet end and outlet end of the mixture, respectively.

7. The dedicated test bench for air preheaters according to claim 6, characterized in that, The flue gas outlet pipe and the liquid outlet pipe are connected by a liquid-gas mixing module, which is located between the liquid inlet end and the filter module corresponding to the liquid inlet end.

8. The dedicated test bench for air preheaters according to claim 1, characterized in that, A delivery pump is connected in series in the liquid inlet pipe, the gas outlet pipe, and the smoke outlet pipe.

9. The dedicated test bench for air preheaters according to claim 1, characterized in that, A first check valve is connected in series on the smoke outlet pipe, and a second check valve is connected in series on the smoke inlet pipe.

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