Flue gas waste heat recovery system

Abstract

The invention provides a flue gas waste heat recovery system, and relates to the technical field of waste heat recovery, the flue gas waste heat recovery system comprises a plate heat exchanger and a control system, the plate heat exchanger is connected with a flue gas inlet pipe, a flue gas outlet pipe, a medium liquid inlet pipe and a medium liquid outlet pipe, and the flue gas inlet pipe is provided with a flue gas monitoring module; the flue gas monitoring module is used for monitoring the monitoring property of flue gas, the medium liquid inlet pipe is provided with a medium monitoring module and a control valve, the medium monitoring module is used for monitoring the monitoring property of a heat exchange medium, the control system is electrically connected with the control valve, and the control system is in communication connection with the flue gas monitoring module and the medium monitoring module. According to the flue gas waste heat recovery system, the flue gas detection module and the medium monitoring module are arranged, so that the monitoring property of flue gas and the monitoring property of the heat exchange medium are obtained in time, the introduction flow of the heat exchange medium is adjusted in time through the control system, the high efficiency of the heat exchange process is guaranteed, and the flue gas waste heat recovery efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery, and in particular to a flue gas waste heat recovery system. Background Art

[0002] As one of the main forms of energy supply, coal-fired power plants play an important role in electricity production; however, coal-fired power plants still face a series of challenges in energy transformation and environmental protection, including low energy utilization efficiency and large amounts of flue gas emissions; flue gas waste heat recovery is of great significance to improving the operating efficiency of coal-fired power plants and reducing greenhouse gas emissions.

[0003] Existing flue gas waste heat recovery usually uses fixed equipment parameters and lacks dynamic control of flue gas waste heat recovery, resulting in low flue gas waste heat recovery efficiency. Summary of the invention

[0004] The present invention provides a flue gas waste heat recovery system, which is used to solve the defect in the prior art that there is a lack of dynamic control over flue gas waste heat recovery, resulting in low flue gas waste heat recovery efficiency.

[0005] On the one hand, the present invention provides a flue gas waste heat recovery system, including a plate heat exchanger and a control system, the plate heat exchanger is connected with a flue gas inlet pipe, a flue gas outlet pipe, a medium liquid inlet pipe and a medium liquid outlet pipe, the flue gas inlet pipe is provided with a flue gas monitoring module, the flue gas monitoring module is used to monitor the monitoring properties of the flue gas, the medium liquid inlet pipe is provided with a medium monitoring module and a control valve, the medium monitoring module is used to monitor the monitoring properties of the heat exchange medium, the control system is electrically connected to the control valve, and the control system is communicatively connected to the flue gas monitoring module and the medium monitoring module.

[0006] Preferably, the smoke monitoring module comprises:

[0007] The first detection box is connected with the smoke inlet pipe through a sampling pipe;

[0008] The first sampling unit is used to periodically extract a small amount of smoke from the smoke inlet pipe as a smoke analysis sample;

[0009] A first analysis unit, used to analyze the components of the flue gas analysis sample to determine whether the concentration of each component of the flue gas analysis sample exceeds a corresponding concentration threshold;

[0010] A first temperature sensor is disposed in the smoke inlet pipe and is used to detect the actual temperature of the smoke in the smoke inlet pipe;

[0011] A first pressure sensor is disposed in the smoke inlet pipe and is used to detect the actual smoke pressure in the smoke inlet pipe;

[0012] The first alarm unit generates an alarm when any of the monitored properties of the smoke is not within the corresponding allowable data range.

[0013] Preferably, the medium monitoring module includes:

[0014] The second detection box is connected with the medium liquid inlet pipe through the second sampling pipe;

[0015] The second sampling unit is used to periodically extract a small amount of heat exchange medium from the medium inlet pipe as a medium analysis sample;

[0016] The second analysis unit is used to analyze the components of the medium analysis sample to determine whether the content of each soluble component of the medium analysis sample exceeds the corresponding concentration threshold;

[0017] A second temperature sensor is disposed in the medium inlet pipe and is used to detect the actual temperature of the heat exchange medium in the medium inlet pipe;

[0018] A second pressure sensor is disposed in the medium inlet pipe and is used to detect the actual pressure of the heat exchange medium in the medium inlet pipe;

[0019] The second alarm unit generates an alarm when any item of the monitored properties of the heat exchange medium is not within the corresponding allowable data range.

[0020] Preferably, the control system comprises:

[0021] An information collection module is used to collect real-time monitoring properties of flue gas and heat exchange medium;

[0022] The comprehensive control module is used to adjust the inflow flow of the heat exchange medium according to the monitored properties of the flue gas and the monitored properties of the heat exchange medium.

[0023] Preferably, the comprehensive control module includes:

[0024] A first calculation unit, used to calculate a first adjustment candidate value of an incoming flow rate of a heat exchange medium;

[0025] A verification unit, used to verify the rationality of the first adjustment candidate value, if the verification result of the first adjustment candidate value is reasonable, then adjust the inflow flow rate of the heat exchange medium to the first adjustment candidate value, otherwise calculate the maximum allowable inflow flow rate of the heat exchange medium;

[0026] The second calculation unit is used to calculate the maximum allowable inflow flow rate of the heat exchange medium;

[0027] The regulating unit is used to regulate the incoming flow rate of the heat exchange medium to the maximum allowable incoming flow rate of the heat exchange medium after the maximum allowable incoming flow rate of the heat exchange medium is calculated.

[0028] Preferably, the first calculation unit calculates the first adjustment candidate value based on the following formula:

[0029] Among them, Q1 is the first adjustment alternative value; h1 is the convection heat transfer coefficient between the flue gas and the heat exchange plate; γ is the first correction coefficient; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; A1 is the total number of hot flow cavities of the plate heat exchanger; A2 is the total number of cold flow cavities of the plate heat exchanger; Q y is the flow rate of flue gas; ρ is the density of heat exchange medium; C is the specific heat capacity of heat exchange medium; T3 is the preset target temperature when the heat exchange medium flows out of the plate heat exchanger; t0 is the unit time.

[0030] Preferably, the verification unit includes:

[0031] A calibration coefficient calculation subunit, used to calculate the flow calibration coefficient;

[0032] Wherein, P is the flow calibration coefficient; L is the length of the heat exchange plate; A1 is the total number of hot flow cavities of the plate heat exchanger; A2 is the total number of cold flow cavities of the plate heat exchanger; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; Q1 is the first adjustment alternative value; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; t0 is the unit time; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; T3 is the preset target temperature of the heat exchange medium when it flows out of the plate heat exchanger; h2 is the convection heat transfer coefficient between the heat exchange medium and the heat exchange plate;

[0033] The judgment subunit determines that if the flow rate verification coefficient is greater than 0, the verification result is that the first adjustment candidate value is reasonable, otherwise the verification result is that the first adjustment candidate value is unreasonable.

[0034] Preferably, the second calculation unit calculates the maximum allowable inflow flow rate of the heat exchange medium based on the following formula:

[0035] Among them, Q2 is the maximum allowable inflow flow rate of the heat exchange medium; h2 is the convection heat transfer coefficient between the heat exchange medium and the heat exchange plate; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; T3 is the preset target temperature of the heat exchange medium when it flows out of the plate heat exchanger; A1 is the total number of hot flow cavities of the plate heat exchanger; A2 is the total number of cold flow cavities of the plate heat exchanger; L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; t0 is the unit time.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] By setting up a flue gas detection module and a medium monitoring module, the monitoring properties of the flue gas and the monitoring properties of the heat exchange medium can be obtained in time, so that the inlet flow rate of the heat exchange medium can be adjusted in time through the control system. First, it is ensured that the temperature of the heat exchange medium after heat exchange is within a temperature range suitable for utilization. By appropriately adjusting the inlet flow rate of the heat exchange medium, the high efficiency of the heat exchange process is guaranteed, thereby improving the efficiency of flue gas waste heat recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 It is a structural schematic diagram of the present invention.

[0040] Reference numerals:

[0041] 1. Plate heat exchanger; 2. Flue gas inlet pipe; 3. Flue gas outlet pipe; 4. Medium liquid inlet pipe; 5. Medium liquid outlet pipe; 6. Flue gas monitoring module; 7. Medium monitoring module; 8. Control valve; 9. First detection box; 10. Sampling pipeline one; 11. Second detection box; 12. Sampling pipeline two. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0044] Example 1

[0045] An embodiment of the present invention provides a flue gas waste heat recovery system, including a plate heat exchanger 1 and a control system. The plate heat exchanger 1 is connected to a flue gas inlet pipe 2, a flue gas outlet pipe 3, a medium liquid inlet pipe 4 and a medium liquid outlet pipe 5. The flue gas inlet pipe 2 is provided with a flue gas monitoring module 6, and the flue gas monitoring module 6 is used to monitor the monitoring properties of the flue gas. The medium liquid inlet pipe 4 is provided with a medium monitoring module 7 and a control valve 8, and the medium monitoring module 7 is used to monitor the monitoring properties of the heat exchange medium. The control system is electrically connected to the control valve 8, and the control system is communicatively connected to the flue gas monitoring module 6 and the medium monitoring module 7.

[0046] Preferably, the smoke monitoring module 6 comprises:

[0047] The first detection box 9 is connected to the smoke inlet pipe 2 through a sampling pipe 10;

[0048] The first sampling unit is used to periodically extract a small amount of smoke from the smoke inlet pipe 2 as a smoke analysis sample;

[0049] A first analysis unit, used to analyze the components of the flue gas analysis sample to determine whether the concentration of each component of the flue gas analysis sample exceeds a corresponding concentration threshold;

[0050] A first temperature sensor is disposed in the smoke inlet pipe 2 and is used to detect the actual temperature of the smoke in the smoke inlet pipe 2;

[0051] A first pressure sensor is disposed in the smoke inlet pipe 2 and is used to detect the actual smoke pressure in the smoke inlet pipe 2;

[0052] The first alarm unit generates an alarm when any of the monitored properties of the smoke is not within the corresponding allowable data range.

[0053] Preferably, the medium monitoring module 7 includes:

[0054] The second detection box 11 is connected to the medium inlet pipe 4 through the sampling pipe 2 12;

[0055] The second sampling unit is used to periodically extract a small amount of heat exchange medium from the medium inlet pipe 4 as a medium analysis sample;

[0056] The second analysis unit is used to analyze the components of the medium analysis sample to determine whether the content of each soluble component of the medium analysis sample exceeds the corresponding concentration threshold;

[0057] The second temperature sensor is arranged in the medium inlet pipe 4 and is used to detect the actual temperature of the heat exchange medium in the medium inlet pipe 4;

[0058] A second pressure sensor is disposed in the medium inlet pipe 4 and is used to detect the actual pressure of the heat exchange medium in the medium inlet pipe 4;

[0059] The second alarm unit generates an alarm when any item of the monitored properties of the heat exchange medium is not within the corresponding allowable data range.

[0060] Preferably, the control system comprises:

[0061] An information collection module is used to collect real-time monitoring properties of flue gas and heat exchange medium;

[0062] The comprehensive control module is used to adjust the inflow flow of the heat exchange medium according to the monitored properties of the flue gas and the monitored properties of the heat exchange medium.

[0063] In this embodiment, the monitored properties of the flue gas include the composition, temperature, and pressure of the flue gas.

[0064] In this embodiment, the monitored properties of the heat exchange medium include the temperature, pressure, and soluble component content of the heat exchange medium.

[0065] The beneficial effects of the above technical solution are:

[0066] By setting up the flue gas detection module and the medium monitoring module 7, the monitoring properties of the flue gas and the monitoring properties of the heat exchange medium can be obtained in time, so that the inlet flow rate of the heat exchange medium can be adjusted in time through the control system. First, it is ensured that the temperature of the heat exchange medium after heat exchange is within a temperature range suitable for utilization. By appropriately adjusting the inlet flow rate of the heat exchange medium, the high efficiency of the heat exchange process is guaranteed, thereby improving the efficiency of flue gas waste heat recovery.

[0067] Example 2

[0068] Based on Example 1, the comprehensive control module includes:

[0069] A first calculation unit, used to calculate a first adjustment candidate value of an incoming flow rate of a heat exchange medium;

[0070] A verification unit, used to verify the rationality of the first adjustment candidate value, if the verification result of the first adjustment candidate value is reasonable, then adjust the inflow flow rate of the heat exchange medium to the first adjustment candidate value, otherwise calculate the maximum allowable inflow flow rate of the heat exchange medium;

[0071] The second calculation unit is used to calculate the maximum allowable inflow flow rate of the heat exchange medium;

[0072] The regulating unit is used to regulate the incoming flow rate of the heat exchange medium to the maximum allowable incoming flow rate of the heat exchange medium after the maximum allowable incoming flow rate of the heat exchange medium is calculated.

[0073] Preferably, the first calculation unit calculates the first adjustment candidate value based on the following formula:

[0074] Among them, Q1 is the first adjustment alternative value; h1 is the convection heat transfer coefficient between the flue gas and the heat exchange plate; γ is the first correction coefficient; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; A1 is the total number of hot flow cavities of the plate heat exchanger 1; A2 is the total number of cold flow cavities of the plate heat exchanger 1; Q y is the flow rate of flue gas; ρ is the density of heat exchange medium; C is the specific heat capacity of heat exchange medium; T3 is the preset target temperature when the heat exchange medium flows out of the plate heat exchanger 1; t0 is the unit time.

[0075] Preferably, the verification unit includes:

[0076] A calibration coefficient calculation subunit, used to calculate the flow calibration coefficient;

[0077] Wherein, P is the flow calibration coefficient; L is the length of the heat exchange plate; A1 is the total number of hot flow cavities of the plate heat exchanger 1; A2 is the total number of cold flow cavities of the plate heat exchanger 1; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; Q1 is the first adjustment alternative value; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; t0 is the unit time; T1 is the actual temperature when the flue gas enters the plate heat exchanger; T2 is the actual temperature when the heat exchange medium enters the plate heat exchanger; T3 is the preset target temperature when the heat exchange medium flows out of the plate heat exchanger 1; h2 is the convection heat transfer coefficient between the heat exchange medium and the heat exchange plate;

[0078] The judgment subunit determines that if the flow rate verification coefficient is greater than 0, the verification result is that the first adjustment candidate value is reasonable, otherwise the verification result is that the first adjustment candidate value is unreasonable.

[0079] Preferably, the second calculation unit calculates the maximum allowable inflow flow rate of the heat exchange medium based on the following formula:

[0080] Among them, Q2 is the maximum allowable inflow flow rate of the heat exchange medium; h2 is the convection heat transfer coefficient between the heat exchange medium and the heat exchange plate; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; T3 is the preset target temperature of the heat exchange medium when it flows out of the plate heat exchanger 1; A1 is the total number of hot flow cavities of the plate heat exchanger 1; A2 is the total number of cold flow cavities of the plate heat exchanger 1; L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; t0 is the unit time.

[0081] In this embodiment, the value of the first correction coefficient is less than 1. The first correction coefficient is used to correct the difference between the calculated value and the actual value caused by energy dissipation in the heat exchange process. The first correction coefficient is an empirical value obtained based on experimental fitting.

[0082] In this embodiment, the hot flow cavity is a channel for the flow of smoke, and the cold flow cavity is a channel for the flow of heat exchange medium.

[0083] The beneficial effects of the above technical solution are:

[0084] When adjusting the inlet flow rate of the heat exchange medium, firstly, according to the monitored properties of the flue gas, calculate the maximum allowable flow rate value of the heat exchange medium that can be met under the condition of maximum heat exchange efficiency between the flue gas and the heat exchange plates inside the heat exchanger as the first adjustment alternative value of the inlet flow rate of the heat exchange medium, and further determine through calculation of the verification coefficient whether the heat exchange medium can reach the preset target temperature in the process of passing through the plate heat exchanger 1 under the condition of the first adjustment alternative value, so as to determine whether the heat exchange medium obtained by using the first adjustment alternative value as the flow rate of the heat exchange medium can reach the preset target temperature. If the target temperature can be reached, the flow value of the heat exchange medium is adjusted to the first adjustment alternative value, so as to maximize the efficiency of flue gas waste heat recovery.

[0085] When the heat exchange medium obtained by using the first adjustment alternative value as the flow rate of the heat exchange medium cannot reach the preset target temperature, the maximum allowable inlet flow rate of the heat exchange medium is calculated and the inlet flow rate of the heat exchange medium is adjusted to the maximum allowable inlet flow rate of the heat exchange medium, thereby maximizing the efficiency of flue gas waste heat recovery while ensuring that the temperature of the heat exchange medium is appropriate, thereby improving the flue gas waste heat recovery efficiency and ensuring the high reliability of the flue gas waste heat recovery system.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flue gas waste heat recovery system, characterized in that: The invention comprises a plate heat exchanger (1) and a control system. The plate heat exchanger (1) is connected with a smoke inlet pipe (2), a smoke outlet pipe (3), a medium liquid inlet pipe (4) and a medium liquid outlet pipe (5). The smoke inlet pipe (2) is provided with a smoke monitoring module (6). The smoke monitoring module (6) is used to monitor the monitoring properties of the smoke. The medium liquid inlet pipe (4) is provided with a medium monitoring module (7) and a control valve (8). The medium monitoring module (7) is used to monitor the monitoring properties of the heat exchange medium. The control system is electrically connected to the control valve (8). The control system is communicatively connected to the smoke monitoring module (6) and the medium monitoring module (7).

2. A flue gas waste heat recovery system according to claim 1, characterized in that: The smoke monitoring module (6) comprises: A first detection box (9) is connected to the smoke inlet pipe (2) via a sampling pipe (10); A first sampling unit, used for regularly extracting a small amount of smoke from the smoke inlet pipe (2) as a smoke analysis sample; A first analysis unit, used to analyze the components of the flue gas analysis sample to determine whether the concentration of each component of the flue gas analysis sample exceeds a corresponding concentration threshold; A first temperature sensor is arranged in the smoke inlet pipe (2) and is used to detect the actual temperature of the smoke in the smoke inlet pipe (2); A first pressure sensor is arranged in the smoke inlet pipe (2) and is used to detect the actual smoke pressure in the smoke inlet pipe (2); The first alarm unit generates an alarm when any of the monitored properties of the smoke is not within the corresponding allowable data range.

3. The flue gas waste heat recovery system according to claim 1, characterized in that: The medium monitoring module (7) comprises: The second detection box (11) is connected to the medium liquid inlet pipe (4) through a second sampling pipe (12); A second sampling unit is used to periodically extract a small amount of heat exchange medium from the medium inlet pipe (4) as a medium analysis sample; The second analysis unit is used to analyze the components of the medium analysis sample to determine whether the content of each soluble component of the medium analysis sample exceeds the corresponding concentration threshold; A second temperature sensor is arranged in the medium inlet pipe (4) and is used to detect the actual temperature of the heat exchange medium in the medium inlet pipe (4); A second pressure sensor is arranged in the medium inlet pipe (4) and is used to detect the actual pressure of the heat exchange medium in the medium inlet pipe (4); The second alarm unit generates an alarm when any item of the monitored properties of the heat exchange medium is not within the corresponding allowable data range.

4. The flue gas waste heat recovery system according to claim 1, characterized in that: The control system includes: An information collection module is used to collect real-time monitoring properties of flue gas and heat exchange medium; The comprehensive control module is used to adjust the inflow flow of the heat exchange medium according to the monitored properties of the flue gas and the monitored properties of the heat exchange medium.

5. The flue gas waste heat recovery system according to claim 4, characterized in that: The comprehensive control module includes: A first calculation unit, used to calculate a first adjustment candidate value of an incoming flow rate of a heat exchange medium; A verification unit, used to verify the rationality of the first adjustment candidate value, if the verification result of the first adjustment candidate value is reasonable, then adjust the inflow flow rate of the heat exchange medium to the first adjustment candidate value, otherwise calculate the maximum allowable inflow flow rate of the heat exchange medium; The second calculation unit is used to calculate the maximum allowable inflow flow rate of the heat exchange medium; The regulating unit is used to regulate the incoming flow rate of the heat exchange medium to the maximum allowable incoming flow rate of the heat exchange medium after the maximum allowable incoming flow rate of the heat exchange medium is calculated.

6. A flue gas waste heat recovery system according to claim 5, characterized in that: The first calculation unit calculates the first adjustment candidate value based on the following formula: Wherein, Q1 is the first adjustment candidate value; h1 is the convective heat transfer coefficient between the flue gas and the heat exchange plate; γ is the first correction coefficient; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; A1 is the total number of hot flow cavities of the plate heat exchanger (1); A2 is the total number of cold flow cavities of the plate heat exchanger (1); Q y is the flow rate of flue gas; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; T3 is the preset target temperature when the heat exchange medium flows out of the plate heat exchanger (1); and t0 is the unit time.

7. A flue gas waste heat recovery system according to claim 6, characterized in that: The calibration unit includes: A calibration coefficient calculation subunit, used to calculate the flow calibration coefficient; Wherein, P is the flow rate calibration coefficient; L is the length of the heat exchange plate; A1 is the total number of hot flow cavities of the plate heat exchanger (1); A2 is the total number of cold flow cavities of the plate heat exchanger (1); D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; Q1 is the first adjustment candidate value; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; t0 is the unit time; T1 is the actual temperature of the flue gas when it enters the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when it enters the plate heat exchanger; T3 is the preset target temperature of the heat exchange medium when it flows out of the plate heat exchanger (1); h2 is the convection heat transfer coefficient between the heat exchange medium and the heat exchange plate; The judgment subunit determines that if the flow rate verification coefficient is greater than 0, the verification result is that the first adjustment candidate value is reasonable, otherwise the verification result is that the first adjustment candidate value is unreasonable.

8. A flue gas waste heat recovery system according to claim 5, characterized in that: The second calculation unit calculates the maximum allowable inflow flow rate of the heat exchange medium based on the following formula: Wherein, Q2 is the maximum allowable inflow flow rate of the heat exchange medium; h2 is the convective heat transfer coefficient between the heat exchange medium and the heat exchange plate; T1 is the actual temperature of the flue gas when entering the plate heat exchanger; T2 is the actual temperature of the heat exchange medium when entering the plate heat exchanger; T3 is the preset target temperature of the heat exchange medium when flowing out of the plate heat exchanger (1); A1 is the total number of hot flow cavities of the plate heat exchanger (1); A2 is the total number of cold flow cavities of the plate heat exchanger (1); L is the length of the heat exchange plate; D is the width of the heat exchange plate; S is the plate spacing between the heat exchange plates; ρ is the density of the heat exchange medium; C is the specific heat capacity of the heat exchange medium; and t0 is the unit time.

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