Environment-friendly, energy-saving and efficient flue gas heat exchanger and control method thereof

Abstract

The invention provides an environment-friendly, energy-saving and efficient flue gas heat exchanger and a control method thereof, and relates to the technical field of flue gas heat exchangers, the flue gas heat exchanger comprises a heat exchanger body, the heat exchanger body comprises a guide cylinder, a heat exchange space is formed in the guide cylinder, a smoke inlet communicated with the heat exchange space is formed in one end of the guide cylinder in the extending direction, and a heat exchange pipe is arranged in the heat exchange space; to-be-heated fluid circulates in the smoke inlet, and the smoke inlet is used for conveying high-temperature smoke into the heat exchange space and between the inner wall of the guide cylinder and the outer wall of the heat exchange pipe; the heat storage assembly is arranged outside the heat exchange space and close to the smoke inlet side, the heat storage assembly is used for guiding out part of the high-temperature smoke in the heat exchange space and storing heat of the guided-out part of the high-temperature smoke, and the stored heat can be used for adjusting the temperature of the fluid to be heated circulating in the heat exchange pipe. According to the scheme, the precision and controllability of the heating process can be greatly improved, the stability of product quality can be improved, and the utilization efficiency of energy is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of flue gas heat exchangers, and in particular to an environmentally friendly, energy-saving and efficient flue gas heat exchanger and a control method thereof. Background Art

[0002] In traditional industrial production, for processes that require the use of high-temperature flue gas to heat an object to be heated, the degree of heating of the object to be heated is often controlled by adjusting the amount of smoke entering the smoke inlet. However, this method has many problems.

[0003] On the one hand, frequent adjustment of the smoke intake will affect the stability of the entire smoke circulation system, which may lead to pressure fluctuations, uneven airflow, etc., and thus affect the normal operation of the system.

[0004] On the other hand, when the heat required by the object to be heated is not high, the excess heat is directly discharged with the flue gas, causing a large amount of energy waste, which is not in line with the current development trend of energy conservation and emission reduction.

[0005] Therefore, this extensive heating method is difficult to meet production needs. Summary of the invention

[0006] In view of the above-mentioned defects or deficiencies in the prior art, the present application aims to provide an environmentally friendly, energy-saving and efficient flue gas heat exchanger and a control method thereof, so as to provide a heating method for finely utilizing the heated flue gas.

[0007] In a first aspect, the present application proposes an environmentally friendly, energy-saving and efficient flue gas heat exchanger, comprising: A heat exchanger body, the heat exchanger body comprising a guide tube, the guide tube having a heat exchange space therein, one end of the guide tube along its extension direction having a smoke inlet connected to the heat exchange space, the heat exchange space having a heat exchange tube, the heat exchange tube having a fluid to be heated flowing therein, the smoke inlet being used to transport high-temperature smoke into the heat exchange space and between the inner wall of the guide tube and the outer wall of the heat exchange tube; A heat storage component is arranged outside the heat exchange space and close to the smoke inlet side. The heat storage component is used to extract part of the high-temperature flue gas in the heat exchange space and store the heat of the extracted part of the high-temperature flue gas. The stored heat can be used to adjust the temperature of the fluid to be heated flowing in the heat exchange tube.

[0008] According to the technical solution provided in the embodiment of the present application, the guide tube has a guide port and an escape port near the smoke inlet, and the heat exchange tube has a temperature regulating port coaxially arranged with the escape port near the smoke inlet; The heat storage component comprises: A heat storage chamber, wherein a phase change material is provided in the heat storage chamber, and the phase change material stores or releases heat through its phase change; A heat storage part, the heat storage part comprises a first shunt pipe and a first valve provided at the diversion port, one end of the first shunt pipe is communicated with the first inlet of the heat storage chamber, the other end of the first shunt pipe is connected to the diversion port, and the first valve is used to control the connection / blocking and the connection ratio between the diversion port and the first shunt pipe; A temperature regulating part, the temperature regulating part comprises a second shunt pipe and a second valve arranged at the temperature regulating port, one end of the second shunt pipe is communicated with the first outlet of the heat storage chamber, the other end of the second shunt pipe passes through the avoidance port and is connected to the temperature regulating port, and the second valve is used to control the connection / blocking and the connection ratio between the temperature regulating port and the second shunt pipe.

[0009] According to the technical solution provided in the embodiment of the present application, the fluid to be heated has a target absorption heat, and the high-temperature flue gas entering from the smoke inlet has exchangeable heat; when the target absorption heat is greater than the exchangeable heat, the guide port is connected to the first diversion pipe, and the temperature regulating port is blocked from the second diversion pipe; when the target absorption heat is less than the exchangeable heat, the guide port is blocked from the first diversion pipe, and the temperature regulating port is connected to the second diversion pipe.

[0010] According to the technical solution provided in the embodiment of the present application, the heat storage chamber includes a plurality of first sub-chambers sequentially connected in series along its extension direction, and the phase change temperature of the phase change material in each of the first sub-chambers is different.

[0011] According to the technical solution provided in the embodiment of the present application, the phase change temperature of the phase change material in each of the first sub-cavities gradually decreases in a direction gradually away from the guide tube.

[0012] According to the technical solution provided in the embodiment of the present application, the other end of the guide tube along its extension direction has a smoke outlet connected to the heat exchange space, and the smoke outlet is connected to the smoke treatment device; the heat storage chamber is also connected to an air outlet pipe, and the air outlet pipe is connected to the smoke treatment device.

[0013] In a second aspect, the present application proposes a control method for an environmentally friendly, energy-saving and efficient flue gas heat exchanger, which is used to control the environmentally friendly, energy-saving and efficient flue gas heat exchanger as described above, comprising the following steps: Obtaining a target absorbed heat amount of the fluid to be heated within a target production cycle; At the beginning of the target production cycle, at intervals of a first preset time, the exchangeable heat of the high-temperature flue gas entering from the smoke inlet is obtained in real time; If the exchangeable heat is greater than the target absorbed heat, and the absolute value of the difference between the exchangeable heat and the target absorbed heat is greater than a first preset threshold, the first valve is controlled to open and the second valve is controlled to close, so that the diversion port is connected to the first diversion pipe and the temperature regulating port is blocked from the second diversion pipe.

[0014] According to the technical solution provided in the embodiment of the present application, the fluid to be heated is preheated air, and the heat exchange tube has an air outlet at the end close to the smoke inlet, and the air outlet is connected to the air inlet of the boiler device; The step of obtaining the target absorbed heat of the fluid to be heated within the target production cycle specifically comprises the following steps: Obtaining a target total heat of combustion released by the combustion of fuel in the boiler device within a target production cycle, as well as the thermal efficiency of the boiler device and a preheated air heat ratio, wherein the preheated air heat ratio is a ratio of the heat absorbed by the preheated air to the target total heat of combustion, and the preheated air provides a medium for the full combustion of the fuel; The target absorbed heat is obtained according to the target total combustion heat, the preheated air heat ratio and the thermal efficiency.

[0015] According to the technical solution provided in the embodiment of the present application, the smoke inlet is connected to the smoke exhaust port of the smoke generating device through a smoke inlet pipe; The real-time acquisition of the exchangeable heat of the high-temperature flue gas entering from the smoke inlet specifically includes the following steps: Acquire component information of the high-temperature flue gas in real time, wherein the component information at least includes component type and component ratio; According to the component type, the corresponding component specific heat capacity is obtained, and according to the component specific heat capacity and the component ratio, the flue gas specific heat capacity is obtained; The smoke intake volume and smoke intake temperature of the high-temperature smoke entering through the smoke inlet are obtained in real time, and the exchangeable heat of the high-temperature smoke entering through the smoke inlet is obtained in real time based on the smoke intake volume, smoke intake temperature, target smoke outlet temperature, and the smoke specific heat capacity; the target smoke outlet temperature is the current ambient temperature.

[0016] According to the technical solution provided in the embodiment of the present application, the controlling the first valve to open specifically includes the following steps: Taking the difference between the exchangeable heat and the target absorbed heat and the quotient of the exchangeable heat as the difference ratio; A first opening degree is obtained according to the difference ratio, and the first valve is controlled to open at the first opening degree.

[0017] Compared with the prior art, the beneficial effect of the present application is that the present application realizes that the object to be heated can be heated to the target heat without adjusting the smoke intake of the smoke inlet by setting a heat storage component. When the object to be heated requires less heat, the heat storage component can store the excess heat of the smoke in time, avoiding the waste of heat with the exhaust of the smoke. When the object to be heated requires more heat but the heat carried by the smoke currently flowing into the smoke inlet is not enough, the heat storage component can release the stored heat and work together with the smoke circulating in the guide tube to ensure that the object to be heated reaches the target heat. This method greatly improves the accuracy and controllability of the heating process and helps to improve the stability of product quality. Since it is no longer necessary to frequently adjust the smoke intake of the smoke inlet, the stability of the entire smoke circulation system has been significantly improved, reducing the pressure fluctuations and uneven airflow caused by changes in the smoke intake, reducing the adverse effects on other related equipment, and ensuring the stable operation of the entire production system. At the same time, it greatly improves the efficiency of energy utilization, conforms to the development concept of energy conservation and emission reduction, helps enterprises reduce energy consumption and costs, and also contributes to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of an environmentally friendly, energy-saving and efficient flue gas heat exchanger (one heat exchange tube) provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of an environmentally friendly, energy-saving and efficient flue gas heat exchanger (multiple heat exchange tubes) provided in an embodiment of the present application; Figure 3 A flow chart of the steps of the valve in the control method of the environmentally friendly, energy-saving and efficient flue gas heat exchanger provided in the embodiment of the present application.

[0019] The text annotations in the figure represent: 1. Boiler device; 2. Heat storage component; 21. Heat storage chamber; 22. First branch pipe; 23. First valve; 24. Second valve; 25. Second branch pipe; 3. Guide tube; 31. Heat exchange space; 32. Smoke inlet; 4. Heat exchange tube; 41. Heat exchange tube air inlet; 42. Heat exchange tube air outlet; 43. Main pipe; 44. Branch pipe; 5. Smoke treatment device. DETAILED DESCRIPTION

[0020] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] Example 1 As mentioned in the background technology, in view of the problems in the prior art, this application proposes an environmentally friendly, energy-saving and efficient flue gas heat exchanger, such as Figure 1 As shown, including: The heat exchanger body comprises a guide tube 3, wherein the guide tube 3 has a heat exchange space 31, and one end of the guide tube 3 along its extension direction has a smoke inlet 32 ​​connected to the heat exchange space 31, wherein the heat exchange space 31 has a heat exchange tube 4, wherein the heat exchange tube 4 has a fluid to be heated, and the smoke inlet 32 ​​is used to transport high-temperature smoke into the heat exchange space 31 and between the inner wall of the guide tube 3 and the outer wall of the heat exchange tube 4; Specifically, the guide tube 3 is cylindrical in design, and its length is determined according to the actual heat exchange requirements. Its material is stainless steel that is resistant to high temperatures and has good thermal conductivity. The smoke inlet 32 ​​is located at one end of the guide tube 3. Its shape is circular, and its diameter is about one-third of the diameter of the guide tube 3. It is tightly connected to the guide tube 3 by welding to ensure that the high-temperature flue gas can smoothly enter the heat exchange space 31 without leakage. The heat exchange tube 4 can be a ( Figure 1 As shown), there may also be multiple heat exchange tubes. When there are multiple heat exchange tubes 4, the heat exchange tubes 4 include a plurality of branch tubes 44 and a main tube 43 (as shown) arranged near the smoke inlet 32. Figure 2 As shown in the figure, multiple branch pipes 44 are connected to the smoke inlet 32 ​​through the main pipe 43, that is, one end of the main pipe 43 is connected to the smoke inlet 32, and the other end is connected to multiple branch pipes 44. The heat exchange tube 4 can be a copper tube, which has good thermal conductivity and can effectively exchange the heat of the flue gas to the fluid to be heated. The two ends of the heat exchange tube 4 pass through the guide tube 3 respectively, and are fixed on the guide tube 3 by welding and sealing. One end is the heat exchange tube air inlet 41 for the entry of the fluid to be heated, and the other end is the heat exchange tube air outlet 42 for the discharge of the fluid to be heated. The heat exchange tube air inlet 41 and the heat exchange tube air outlet 42 are both connected with corresponding pipelines for conveying the fluid to be heated.

[0023] The heat storage component 2 is arranged outside the heat exchange space 31 and close to the smoke inlet 32. The heat storage component 2 is used to extract part of the high-temperature flue gas in the heat exchange space 31 and store the heat of the extracted part of the high-temperature flue gas. The stored heat can be used to adjust the temperature of the fluid to be heated flowing in the heat exchange tube 4.

[0024] Furthermore, the guide tube 3 has a guide port and an escape port on the side close to the smoke inlet 32, and the heat exchange tube 4 has a temperature regulating port coaxially arranged with the escape port on the side close to the smoke inlet 32; The heat storage assembly 2 comprises: A heat storage chamber 21, wherein the heat storage chamber 21 has a phase change material therein, and the phase change material stores or releases heat through its phase change; A heat storage part, the heat storage part comprises a first shunt pipe 22 and a first valve 23 provided at the diversion port, one end of the first shunt pipe 22 is communicated with the first inlet of the heat storage chamber 21, the other end of the first shunt pipe 22 is connected to the diversion port, and the first valve 23 is used to control the connection / blocking of the diversion port and the first shunt pipe 22, as well as the connection ratio; The temperature regulating part includes a second shunt pipe 25 and a second valve 24 provided at the temperature regulating port, one end of the second shunt pipe 25 is communicated with the first outlet of the heat storage chamber 21, the other end of the second shunt pipe 25 passes through the avoidance port and is connected to the temperature regulating port, and the second valve 24 is used to control the connection / blocking and the connection ratio between the temperature regulating port and the second shunt pipe 25.

[0025] Specifically, the heat storage chamber 21 is in the shape of a rectangular parallelepiped and is made of ceramic material with good heat insulation performance to reduce heat loss. The phase change material can be paraffin, which can undergo phase change under the heat of high-temperature flue gas, thereby storing heat and releasing heat when needed. The first shunt pipe 22 of the heat storage part is a circular pipe made of a high-temperature resistant alloy material. One end of the first shunt pipe 22 is connected to the first inlet of the heat storage chamber 21 by a threaded connection to ensure the tightness and sealing of the connection to prevent heat leakage. The other end of the first shunt pipe 22 is welded to the diversion port, which is located below the side of the diversion tube 3 close to the smoke inlet 32, and its diameter matches the first shunt pipe 22. The first valve 23 is installed at the connection between the first shunt pipe 22 and the diversion port, and an electric regulating valve is used to accurately control the connection / blocking and connection ratio of the diversion port and the first shunt pipe 22. The second shunt pipe 25 of the temperature regulating part is also a circular pipe, and the material is the same as the first shunt pipe 22. One end of the second diverter pipe 25 is threadedly connected to the first outlet of the heat storage chamber 21, and the other end is welded to the temperature regulating port on the side of the heat exchange tube 4 close to the smoke inlet 32. The temperature regulating port is located on the side of the heat exchange tube 4, and the diameter is adapted to the second diverter pipe 25. In order to meet the sealing effect, the first diverter pipe 22 and the second diverter pipe 25 can be integrally formed with the guide tube 3 and the heat exchange tube 4. The second valve 24 is installed at the connection between the second diverter pipe 25 and the temperature regulating port. An electric regulating valve is also used. The connection / blocking and the connection ratio of the temperature regulating port and the second diverter pipe 25 can be accurately controlled according to actual needs, so as to achieve precise temperature control of the heated fluid.

[0026] It should be noted that when there is only one heat exchange tube 4 , the temperature regulating port is arranged on the side of the heat exchange tube 4 close to the smoke inlet 32 ​​; when the heat exchange tube 4 includes several branch pipes 44 and a main pipe 43 arranged close to the smoke inlet 32 ​​, the temperature regulating port is arranged on the main pipe 43 .

[0027] The working principle of the flue gas heat exchanger: During the actual operation, the high-temperature flue gas enters the heat exchange space 31 from the smoke inlet 32, and most of the flue gas flows between the inner wall of the guide tube 3 and the outer wall of the heat exchange tube 4, exchanging heat with the fluid to be heated in the heat exchange tube 4. At the same time, according to the temperature requirements of the system, the first valve 23 is opened to a certain proportion, so that part of the high-temperature flue gas enters the heat storage chamber 21 through the first shunt pipe 22, and the phase change material absorbs the heat of the flue gas and undergoes phase change and stores it. When the temperature of the fluid to be heated needs to be adjusted, the second valve 24 is opened to a corresponding proportion, and the heat stored in the heat storage chamber 21 is released to the fluid to be heated in the heat exchange tube 4 through the second shunt pipe 25 and the temperature regulating port, thereby realizing precise adjustment of the fluid temperature and achieving environmentally friendly, energy-saving and efficient heat exchange effects.

[0028] In a preferred embodiment, the fluid to be heated has a target absorption heat, and the high-temperature flue gas entering from the smoke inlet 32 ​​has exchangeable heat; when the target absorption heat is greater than the exchangeable heat, the guide port is connected to the first diversion pipe 22, and the temperature regulating port is blocked from the second diversion pipe 25; when the target absorption heat is less than the exchangeable heat, the guide port is blocked from the first diversion pipe 22, and the temperature regulating port is connected to the second diversion pipe 25.

[0029] Specifically, in the heat exchanger system, a heat monitoring device is installed, which is respectively located at the inlet pipe of the fluid to be heated and the smoke inlet 32 ​​pipe of the high-temperature flue gas. These heat monitoring devices can use high-precision thermocouple thermometers and flow meters to calculate the target absorbed heat of the fluid to be heated and the exchangeable heat of the high-temperature flue gas by measuring parameters such as the temperature, flow rate and specific heat capacity of the fluid. The control system is connected to the heat monitoring device and the first and second valves 24. When it is calculated that the target absorbed heat is greater than the exchangeable heat, the control system sends an opening signal to the first valve 23 to open it to a certain proportion, and at the same time sends a closing signal to the second valve 24 to ensure that the diversion port is connected to the first shunt pipe 22 and the temperature regulating port is blocked from the second shunt pipe 25, so that part of the high-temperature flue gas enters the heat storage chamber 21 to store heat to cope with possible subsequent heat requirements. For example, in a certain process link in industrial production, the fluid to be heated needs to be quickly heated to a specific temperature, and the heat of the high-temperature flue gas entering at this time is not enough to meet the demand, and the system will automatically perform the above operation.

[0030] On the contrary, when the target absorbed heat is less than the exchangeable heat, the control system closes the first valve 23 and opens the second valve 24, so that the diversion port is blocked from the first shunt pipe 22 and the temperature regulating port is connected to the second shunt pipe 25, and the heat stored in the heat storage chamber 21 is released into the fluid to be heated, thereby achieving precise temperature control and rational use of energy.

[0031] In a preferred embodiment, the heat storage chamber 21 includes a plurality of first sub-chambers sequentially connected in series along its extension direction, and the phase change temperature of the phase change material in each of the first sub-chambers is different.

[0032] Specifically, a plurality of partitions are arranged inside the heat storage chamber 21 along its extension direction, dividing the heat storage chamber 21 into a plurality of first sub-cavities. The size of each first sub-cavity is designed according to actual needs, and the size of each first sub-cavity can be the same or different. Adjacent partitions are sealed with sealing strips to prevent disorderly transfer of heat between sub-cavities. For each first sub-cavity, a phase change material with a different phase change temperature is selected for filling.

[0033] In a preferred embodiment, along a direction gradually away from the guide tube 3 , the phase change temperature of the phase change material in each of the first sub-cavities gradually decreases.

[0034] Specifically, the first sub-chamber near the smoke inlet 32 ​​side uses a phase change material with a higher phase change temperature, such as a certain composite salt phase change material with a melting point of [G]°C, which can effectively absorb and store a large amount of heat when the high-temperature smoke just enters. As the distance from the smoke inlet 32 ​​gradually increases, the subsequent first sub-chambers successively use phase change materials with gradually lower phase change temperatures, such as other suitable phase change materials with melting points of [H]°C, [I]°C, etc., where G is less than H and less than I. In this way, heat can be stored in stages according to changes in smoke temperature, thereby improving heat storage efficiency and the flexibility of heat utilization. In actual applications, when high-temperature smoke enters the heat storage chamber 21, it first exchanges heat with the phase change material in the first sub-chamber with a higher phase change temperature. As the smoke temperature gradually decreases, the subsequent first sub-chambers with different temperatures successively play a heat storage role, which can provide a multi-stage, highly adaptable heat supply for the entire production process.

[0035] In a preferred embodiment, the other end of the guide tube 3 along its extension direction has a smoke outlet connected to the heat exchange space 31, and the smoke outlet is connected to the smoke treatment device 5; the heat storage chamber 21 is also connected to an air outlet pipe, and the air outlet pipe is connected to the smoke treatment device 5.

[0036] Specifically, the smoke outlet of the guide tube 3 is arranged at the other end thereof along the extension direction. The shape of the smoke outlet is circular, and the diameter is about one-fourth of the diameter of the guide tube 3. The smoke outlet is connected to the guide tube 3 by welding. The smoke outlet is connected to a high-temperature resistant metal pipe, which transports the smoke to the smoke treatment device 5. The diameter of the pipe is adapted to the smoke outlet, and the connection is fixed by a sealing gasket and a flange to ensure that the smoke does not leak. The top of the heat storage chamber 21 is connected to an outlet pipe, and the outlet pipe is made of corrosion-resistant plastic or metal. One end of the outlet pipe is connected to the outlet of the heat storage chamber 21 by welding to ensure sealing, and the other end is connected to the smoke treatment air inlet of the smoke treatment device 5. The connection method also adopts a flange connection, which is easy to install and maintain. During the operation of the entire heat exchanger system, the smoke after heat exchange and the smoke after heat storage can smoothly enter the smoke treatment device 5 through the outlet pipe for further purification to meet environmental protection requirements. For example, in some industrial fields with strict requirements on exhaust gas emissions, such as steel, chemical and other industries, this exhaust gas treatment connection method can effectively reduce the pollution of exhaust gas to the environment, while also ensuring the environmental performance of the entire heat exchanger system.

[0037] Example 2 On the basis of Example 1, this example proposes a control method for an environmentally friendly, energy-saving and efficient flue gas heat exchanger, which is used to control the environmentally friendly, energy-saving and efficient flue gas heat exchanger proposed in Example 1, so as to transfer the heat in the high-temperature flue gas to the fluid to be heated (preheated air), and the preheated air is used for combustion when the boiler device 1 burns the dye. This method can improve the energy utilization efficiency and meet the requirements of environmental protection and energy saving; Figure 3 As shown, the control method includes the following steps: S1. Obtaining the target absorbed heat of the fluid to be heated within a target production cycle; Furthermore, the fluid to be heated is preheated air, and the end of the heat exchange tube 4 close to the smoke inlet 32 ​​has an air outlet, and the air outlet is connected to the air inlet of the boiler device 1; The step of obtaining the target absorbed heat of the fluid to be heated within the target production cycle specifically comprises the following steps: Obtaining the target total heat of combustion released by the combustion of fuel in the boiler device 1 within the target production cycle, as well as the thermal efficiency of the boiler device 1 and the preheated air heat ratio, wherein the preheated air heat ratio is the ratio of the heat absorbed by the preheated air to the target total heat of combustion, and the preheated air provides a medium for the full combustion of the fuel; It should be noted that the high-temperature flue gas entering the flue gas heat exchanger may be generated by the boiler device 1 mentioned above (which requires the introduction of preheated air), or may be generated by other flue gas generating devices and then transported through a smoke inlet pipe.

[0038] Specifically, before entering the target production cycle, the boiler operation record log is searched to obtain the fuel type in the target production cycle. Different fuel types have different calorific values. For example, the calorific value of coal is generally around 20-30MJ / kg, and the calorific value of natural gas is about 35-55MJ / m³.

[0039] The target absorbed heat is obtained according to the target total combustion heat, the preheated air heat ratio and the thermal efficiency.

[0040] Specifically, the target total heat of combustion is obtained according to the calorific value corresponding to the fuel type and the total amount of fuel (the two are multiplied). According to the boiler operation record log, the previous production cycles with the same fuel type as the fuel in the target production cycle, the same initial temperature when the preheated air enters the boiler device 1, and the same discharge temperature after the preheated air is discharged from the boiler device 1 after combustion are found, and then the reference total heat of combustion and the reference absorption heat absorbed by the preheated air in the previous production cycle are obtained (both parameters are recorded in the boiler operation record log). According to the reference total heat of combustion and the reference absorption heat, the preheated air heat ratio of the target production cycle is obtained (the reference absorption heat divided by the reference total heat of combustion is the preheated air heat ratio). The thermal efficiency of the boiler device 1 is related to the service life of the device, and the thermal efficiency is calculated based on the service life; the calculation formula for the target absorption heat can be expressed as: target absorption heat = target total heat of combustion × preheated air heat ratio × thermal efficiency.

[0041] Specifically, under normal circumstances, a certain fuel type is often kept unchanged, so the fuel type of the target production cycle can be obtained by searching the boiler operation record log. However, in certain scenarios, such as the original fuel price rising, or industry policy changes, or the original fuel supplier encounters an emergency, such as a natural disaster causing a coal mine to shut down, or natural gas pipeline damage, etc., making it impossible for the company to obtain fuel from the original channel. At this time, the original fuel type needs to be changed. Therefore, before the start of the target production cycle, since the fuel type of the target production cycle has changed relative to the fuel type used in other previous production cycles and has not yet been determined, it cannot be obtained by searching the boiler operation record log. The following method is proposed to solve this problem; Furthermore, obtaining the target total heat of combustion released by the combustion of fuel in the boiler device 1 within the target production cycle specifically includes the following steps: Obtain the fuel type within the target production cycle, and obtain the target total combustion heat according to the fuel type; The method of obtaining the fuel type within the target production cycle specifically includes the following steps: Determine whether a first change condition is met before the start of the target production cycle or during the production process of the previous production cycle, wherein the first change condition at least includes that the price increase of the raw fuel type is greater than a first preset range and the raw fuel type is prohibited by industry policy; If all items in the first change condition are not met, the fuel type of the previous production cycle will be used as the fuel type in the target production cycle; if at least one item in the first change condition is met, the fuel type in the target production cycle will be obtained based on the current energy price table and industry policy.

[0042] Furthermore, obtaining the fuel type within the target production cycle according to the current energy price list and industry policy specifically includes the following steps: A price evaluation model is established based on the production cost budget, energy consumption requirements and profit target factors of the enterprise of the boiler device 1. The input parameters of the price evaluation model include the prices of various fuels (obtained from the current energy price table), the expected purchase volume, the correlation parameters between fuel and production efficiency (for example, a certain fuel may make the operation efficiency of the production equipment higher or lower), etc. The output is the expected cost of various fuels within the target production cycle; Based on the price evaluation model, the estimated cost corresponding to each fuel type is obtained; and among all fuel types, the fuel type that meets industry policies and has the lowest estimated cost is selected as the fuel type within the target production cycle.

[0043] S2. At the beginning of the target production cycle, at intervals of a first preset time, obtaining in real time the exchangeable heat of the high-temperature flue gas entering through the smoke inlet 32; Furthermore, the smoke inlet 32 ​​is connected to the smoke exhaust port of the smoke generating device through a smoke inlet pipe; The real-time acquisition of the exchangeable heat of the high-temperature flue gas entering from the smoke inlet 32 ​​specifically includes the following steps: Acquire component information of the high-temperature flue gas in real time, wherein the component information at least includes component type and component ratio; Specifically, online smoke composition analysis technologies, such as laser spectroscopy analysis, mass spectrometry analysis, etc., can be introduced into the smoke inlet duct to achieve real-time and continuous monitoring of smoke components.

[0044] According to the component type, the corresponding component specific heat capacity is obtained, and according to the component specific heat capacity and the component ratio, the flue gas specific heat capacity is obtained; Specifically, if the proportions of the components in the high-temperature flue gas are x1, x2, ...xn, where the sum of the proportions is 1, the specific heat capacities of the corresponding components are c1, c2, ...cn, respectively. According to the formula Get the specific heat capacity of flue gas.

[0045] The smoke intake volume and smoke intake temperature of the high-temperature smoke entering through the smoke inlet 32 ​​are obtained in real time, and the exchangeable heat of the high-temperature smoke entering through the smoke inlet 32 ​​is obtained in real time based on the smoke intake volume, smoke intake temperature, target smoke outlet temperature, and the smoke specific heat capacity; the target smoke outlet temperature is the current ambient temperature.

[0046] Specifically, according to the formula , and the exchangeable heat , where m is the smoke intake, T1 is the smoke intake temperature, and T2 is the target smoke outlet temperature. is the specific heat capacity of flue gas.

[0047] S3. If the exchangeable heat is greater than the target absorbed heat, and the absolute value of the difference between the exchangeable heat and the target absorbed heat is greater than a first preset threshold, the first valve 23 is controlled to be opened and the second valve 24 is controlled to be closed, so that the guide port is connected to the first diversion pipe 22, and the temperature regulating port is blocked from the second diversion pipe 25.

[0048] Specifically, when the exchangeable heat is greater than the target absorbed heat, and the absolute value of the difference between the two is greater than the first preset threshold, the control output module of the control system sends an opening signal to the first valve 23, and sends a closing signal to the second valve 24, so that the first valve 23 is opened to a predetermined ratio (the ratio can be intelligently adjusted according to the size of the difference, the larger the difference, the larger the opening ratio, to ensure that sufficient heat is stored in the heat storage chamber 21), thereby achieving the connection between the guide port and the first diversion pipe 22, and the blocking of the temperature regulating port and the second diversion pipe 25. In this way, the excess high-temperature flue gas heat will be stored in the heat storage chamber 21, so as to be used when the heat is insufficient in the subsequent production process, realizing efficient use and precise control of heat, ensuring that the temperature of the fluid to be heated is stable within a suitable range during the entire production process, improving production efficiency and product quality, and also reflecting the environmental protection and energy-saving advantages of the heat exchanger.

[0049] During the entire target production cycle, the control system continuously repeats the above steps S2 and S3, monitors and adjusts the heat distribution of the high-temperature flue gas in real time to adapt to the changes in heat demand during the production process, ensures that the heat exchanger system is always in an efficient and stable operating state, and meets the production requirements of environmental protection and energy saving.

[0050] In a preferred embodiment, the controlling the first valve 23 to open specifically includes the following steps: Taking the difference between the exchangeable heat and the target absorbed heat and the quotient of the exchangeable heat as the difference ratio; According to the difference ratio, a first opening degree is obtained, and the first valve 23 is controlled to open at the first opening degree.

[0051] Specifically, the exchangeable heat is Q1, the target absorbed heat is Q0, and the difference ratio is P=(Q1-Q0) / Q1. For example, at a certain moment, the exchangeable heat is 1000 kJ (here is only an example data, and the specific value is obtained by the method of obtaining the exchangeable heat described above in actual situation) through real-time monitoring and calculation, and the target absorbed heat is 800 kJ. Then, according to the above formula, the difference ratio is calculated to be 0.2; according to the difference ratio, the first opening is obtained by looking up the table, and the table lookup is to query the mapping relationship table between the difference ratio and the first opening. The mapping relationship table includes multiple groups of one-to-one corresponding difference ratios and the first opening. Exemplarily, the mapping relationship table includes: , the first opening is 10%; , the first opening is 20%; , the first opening is 30%... Continuing with the above calculated difference ratio of 0.2 as an example, by querying the above mapping relationship table, it can be obtained that the corresponding first opening is 30%.

[0052] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. An environmentally friendly, energy-saving and efficient flue gas heat exchanger, characterized in that: include: A heat exchanger body, the heat exchanger body comprising a guide tube (3), the guide tube (3) having a heat exchange space (31) therein, one end of the guide tube (3) along its extension direction having a smoke inlet (32) connected to the heat exchange space (31), the heat exchange space (31) having a heat exchange tube (4), a fluid to be heated flowing through the heat exchange tube (4), the smoke inlet (32) being used to transport high-temperature smoke into the heat exchange space (31) and between the inner wall of the guide tube (3) and the outer wall of the heat exchange tube (4); A heat storage component (2), the heat storage component (2) being arranged outside the heat exchange space (31) and close to the smoke inlet (32), the heat storage component (2) being used to extract part of the high-temperature smoke in the heat exchange space (31) and store the heat of the extracted part of the high-temperature smoke, and the stored heat can be used to adjust the temperature of the fluid to be heated flowing in the heat exchange tube (4).

2. The environmentally friendly, energy-saving and efficient flue gas heat exchanger according to claim 1 is characterized in that: The guide tube (3) has a guide port and an escape port on the side close to the smoke inlet (32), and the heat exchange tube (4) has a temperature regulating port coaxially arranged with the escape port on the side close to the smoke inlet (32); The heat storage component (2) comprises: A heat storage chamber (21), wherein the heat storage chamber (21) has a phase change material therein, and the phase change material stores or releases heat through its phase change; a heat storage part, the heat storage part comprising a first shunt pipe (22) and a first valve (23) arranged at the diversion port, one end of the first shunt pipe (22) being in communication with a first inlet of the heat storage chamber (21), the other end of the first shunt pipe (22) being connected to the diversion port, the first valve (23) being used to control the connection / blocking and the connection ratio between the diversion port and the first shunt pipe (22); A temperature regulating part, the temperature regulating part comprising a second shunt pipe (25) and a second valve (24) arranged at the temperature regulating port, one end of the second shunt pipe (25) being in communication with the first outlet of the heat storage chamber (21), the other end of the second shunt pipe (25) passing through the avoidance port and connected to the temperature regulating port, the second valve (24) being used to control the connection / blocking and the connection ratio between the temperature regulating port and the second shunt pipe (25).

3. The environmentally friendly, energy-saving and efficient flue gas heat exchanger according to claim 2 is characterized in that: The fluid to be heated has a target absorption heat, and the high-temperature flue gas entering from the smoke inlet (32) has exchangeable heat; when the target absorption heat is greater than the exchangeable heat, the guide port is connected to the first shunt pipe (22), and the temperature adjustment port is blocked from the second shunt pipe (25); when the target absorption heat is less than the exchangeable heat, the guide port is blocked from the first shunt pipe (22), and the temperature adjustment port is connected to the second shunt pipe (25).

4. The environmentally friendly, energy-saving and efficient flue gas heat exchanger according to claim 2 is characterized in that: The heat storage chamber (21) comprises a plurality of first sub-chambers sequentially connected in series along its extension direction, and the phase change temperature of the phase change material in each of the first sub-chambers is different.

5. The environmentally friendly, energy-saving and efficient flue gas heat exchanger according to claim 4 is characterized in that: In a direction gradually moving away from the guide tube (3), the phase change temperature of the phase change material in each of the first sub-cavities gradually decreases.

6. The environmentally friendly, energy-saving and efficient flue gas heat exchanger according to claim 2 is characterized in that: The other end of the guide tube (3) along its extension direction has a smoke outlet connected to the heat exchange space (31), and the smoke outlet is connected to the smoke treatment device (5); the heat storage chamber (21) is also connected to an air outlet pipe, and the air outlet pipe is connected to the smoke treatment device (5).

7. A method for controlling an environmentally friendly, energy-saving and efficient flue gas heat exchanger, used to control the environmentally friendly, energy-saving and efficient flue gas heat exchanger according to any one of claims 2 to 6, characterized in that: The following steps are involved: Obtaining a target absorbed heat amount of the fluid to be heated within a target production cycle; At the beginning of the target production cycle, at intervals of a first preset time, the exchangeable heat of the high-temperature flue gas entering through the smoke inlet (32) is obtained in real time; If the exchangeable heat is greater than the target absorbed heat, and the absolute value of the difference between the exchangeable heat and the target absorbed heat is greater than a first preset threshold, the first valve (23) is controlled to open and the second valve (24) is controlled to close, so that the guide port is connected to the first diversion pipe (22) and the temperature adjustment port is blocked from the second diversion pipe (25).

8. The environmentally friendly, energy-saving and efficient flue gas heat exchanger control method according to claim 7 is characterized in that: The fluid to be heated is preheated air, and the heat exchange tube (4) has an air outlet at the end close to the smoke inlet (32), and the air outlet is connected to the air inlet of the boiler device (1); The step of obtaining the target absorbed heat of the fluid to be heated within the target production cycle specifically comprises the following steps: Obtaining a target total heat of combustion released by the combustion of fuel in the boiler device (1) within a target production cycle, as well as the thermal efficiency of the boiler device (1) and a preheated air heat ratio, wherein the preheated air heat ratio is a ratio of the heat absorbed by the preheated air to the target total heat of combustion, and the preheated air provides a medium for the full combustion of the fuel; The target absorbed heat is obtained according to the target total combustion heat, the preheated air heat ratio and the thermal efficiency.

9. The environmentally friendly, energy-saving and efficient flue gas heat exchanger control method according to claim 7 is characterized in that: The smoke inlet (32) is connected to a smoke exhaust port of a smoke generating device via a smoke inlet pipe; The real-time acquisition of the exchangeable heat of the high-temperature flue gas entering through the smoke inlet (32) specifically comprises the following steps: Acquire component information of the high-temperature flue gas in real time, wherein the component information at least includes component type and component ratio; According to the component type, the corresponding component specific heat capacity is obtained, and according to the component specific heat capacity and the component ratio, the flue gas specific heat capacity is obtained; The smoke intake volume and smoke intake temperature of the high-temperature smoke entering through the smoke inlet (32) are obtained in real time, and the exchangeable heat of the high-temperature smoke entering through the smoke inlet (32) is obtained in real time based on the smoke intake volume, smoke intake temperature, target smoke outlet temperature, and the smoke specific heat capacity; the target smoke outlet temperature is the current ambient temperature.

10. The environmentally friendly, energy-saving and efficient flue gas heat exchanger control method according to claim 7, characterized in that: The controlling the first valve (23) to open specifically comprises the following steps: Taking the difference between the exchangeable heat and the target absorbed heat and the quotient of the exchangeable heat as the difference ratio; A first opening degree is obtained according to the difference ratio, and the first valve (23) is controlled to open at the first opening degree.

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