Intelligent control method for flue corrosion prevention based on coupling of vacuum heat pipe and condensate water

Abstract

The present application relates to the technical field of flue corrosion prevention, and discloses a flue corrosion prevention intelligent control method based on vacuum heat pipe and condensate water coupling. The present application collects the condensate water parameters at the condensate water outlet pipeline of the vacuum heat pipe heat exchanger through the data acquisition module, determines the fault mode through the fault mode intelligent judgment module, the fault mode includes flue gas leakage, external water acidification and uncertain state, realizes the intelligent identification of acid corrosion, the multi-level linkage protection module automatically executes the corrosion prevention control method of isolation, neutralization, dilution and other multi-level protection actions based on the determined fault mode, realizes the intelligent protection of flue corrosion prevention, the self-checking module continuously monitors the condensate water parameters until the condensate water quality returns to the normal standard, sends a stop signal to the multi-level linkage protection module, ends the personalized protection, if the water quality does not return to the normal standard within the preset time, triggers the audible and visual alarm, improves the intelligence and timeliness of the early warning.

Description

Technical Field

[0001] This invention relates to the field of flue corrosion prevention technology, specifically to an intelligent control method for flue corrosion prevention based on the coupling of vacuum heat pipes and condensate. Background Technology

[0002] In flue gas waste heat recovery systems such as industrial boilers, kilns, and waste heat power generation, vacuum heat pipe and condensate coupled heat exchange devices are widely used due to their advantages such as high heat transfer efficiency, compact structure, and fast thermal response. In this device, the evaporation end of the vacuum heat pipe is arranged in the flue to absorb the waste heat of the flue gas. After the working fluid vaporizes, it transfers the heat to the condensation end, which is then carried away by the condensate side, thereby achieving flue gas cooling and waste heat recovery.

[0003] However, this coupling system faces significant corrosion risks during long-term operation, mainly in the following two aspects: Condensate acidification corrosion caused by flue gas leakage: Vacuum heat pipes, operating for extended periods in high-temperature, acidic flue gas environments, may develop perforations or cracks due to stress corrosion, pitting, or manufacturing defects. Once the heat pipe fails, acidic gases in the flue gas will leak to the condensate side, dissolving and forming H₂. + HSO3 Cl Such conditions cause a sharp drop in the pH value of the condensate. Acidic condensate can severely corrode condensate pipes, valves, pumps, and the water-side walls of heat exchangers, leading to leaks, blockages, and even system shutdowns. Simultaneously, corrosion products (such as iron ions) may flow back to the cold end of the heat pipes with the condensate, further exacerbating under-deposit corrosion on the flue side, creating a vicious cycle.

[0004] System corrosion caused by external makeup water acidification: Condensate systems require regular replenishment with softened water, demineralized water, or recovered steam condensate. If the makeup water pretreatment system (such as a sodium ion exchanger or reverse osmosis unit) fails, or if the industrial water source itself has excessive chloride and sulfate ion concentrations, the makeup water will have a low pH and high conductivity. When this externally acidified water source directly enters the condensate system, it will also lower the overall water pH, accelerate the electrochemical corrosion of pipes and heat exchange equipment, and may cause critical components to crack due to the stress corrosion effect of chloride ions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipes and condensate. This method has the advantages of collecting condensate parameters from the vacuum heat pipe heat exchanger, determining the fault mode, and then implementing personalized corrosion prevention protection based on the fault mode. It also continuously monitors the condensate water quality until it returns to normal standards. If the water quality does not return to normal standards within a preset time, an audible and visual alarm is triggered. This invention solves the aforementioned technical problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a smart control method for flue gas corrosion prevention based on the coupling of vacuum heat pipes and condensate, comprising the following steps: S1: The data acquisition module collects condensate parameters at the condensate outlet pipe of the vacuum heat pipe heat exchanger; S2: The fault mode intelligent judgment module determines the fault mode based on the collected condensate parameters. The fault modes include: flue gas leakage, external water acidification, and uncertain state. S3: The multi-level linkage protection module performs personalized protection based on the determined fault modes; S4: The self-test module continuously monitors the condensate parameters until the condensate water quality returns to the normal standard. It then sends a stop signal to the multi-level linkage protection module to end its personalized protection. If the water quality does not return to the normal standard within the preset time, an audible and visual alarm will be triggered.

[0007] As a preferred embodiment of the present invention, the S1 condensate parameters include the real-time pH value, conductivity and chloride ion concentration of the condensate.

[0008] As a preferred embodiment of the present invention, step S2, which determines the fault mode based on the collected condensate parameters, includes the following steps: S2.1: Calculate the rate of change of conductivity and the rate of change of chloride ion concentration; S2.2: Determine the fault mode, specifically: when and and At this time, the fault mode is determined to be flue gas leakage. This indicates the amount of condensate at the current moment. pH value, This indicates the acid etching warning threshold. This indicates the amount of condensate at the current moment. The rate of change of conductivity, Indicates the threshold for a sudden increase in conductivity. This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration. This indicates the steady-state threshold of chloride ion concentration; when and When the fault mode is determined to be external water acidification, the fault mode is determined to be an uncertain state in all other cases.

[0009] As a preferred embodiment of the present invention, the expression for the rate of change of conductivity in S2.1 is as follows:

[0010] in, This indicates the amount of condensate at the current moment. The rate of change of conductivity; This indicates the amount of condensate at the current moment. The electrical conductivity; This indicates the amount of condensate at the current moment. Previous time period The electrical conductivity.

[0011] As a preferred embodiment of the present invention, the expression for the rate of change of chloride ion concentration in S2.1 is as follows:

[0012] in, This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration; This indicates the amount of condensate at the current moment. Chloride ion concentration; This indicates the amount of condensate at the current moment. Previous time period The chloride ion concentration.

[0013] As a preferred technical solution of the present invention, the S3 multi-level linkage protection module includes an isolation leakage heat pipe unit, an alkaline neutralization unit and a transient dilution unit. The isolation leakage heat pipe unit performs protection when the fault mode is determined to be flue gas leakage. Specifically, when the fault mode is flue gas leakage, the condensate inlet valve and outlet valve of the isolation leakage heat pipe unit are opened, and the flue gas side bypass valve is opened.

[0014] As a preferred embodiment of the present invention, the alkaline neutralization unit performs protection when the fault mode is determined to be external water acidification. Specifically, when the fault mode is external water acidification, the alkaline neutralization unit controls the amount of neutralizing agent added via a metering pump, as shown in the following expression:

[0015] in, Indicates the current time The target dosing rate of the neutralizing agent; Indicates the adjustment coefficient; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. pH value; This indicates the amount of condensate at the current moment. Volumetric flow rate; This indicates the density of condensate; Indicates the molar mass of the neutralizing agent; Indicates the molar mass of a hydrogen ion; This indicates taking the maximum value.

[0016] As a preferred embodiment of the present invention, the transient dilution unit performs protection when the fault mode is determined to be an uncertain state, specifically: when the fault mode is an uncertain state, and At that time, among them, This is the acid corrosion hazard threshold. This is the acid etching warning threshold. For condensation water at the current moment The pH value is controlled by a water pump to regulate the flow rate of condensate.

[0017] As a preferred embodiment of the present invention, the relevant expression for controlling the flow rate of condensate by a water pump is as follows:

[0018]

[0019] in, Indicates the current time The target flow rate of condensate; This indicates the condensate flow rate under normal operating conditions. Indicates the acid etching warning threshold; This indicates the amount of condensate at the current moment. pH value; Indicates the acid corrosion hazard threshold; The maximum additional flow coefficient; Indicates the duration of the target traffic; This indicates the total volume of the condensate system; This represents the adjustment coefficient.

[0020] As a preferred embodiment of the present invention, the standard for water quality restoration in step S4 is as follows:

[0021] in, For condensation water at the current moment pH value; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. The rate of change of conductivity; This represents the rate of change of standard conductivity.

[0022] Compared with existing technologies, this invention provides an intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipes and condensate, which has the following beneficial effects: This invention collects condensate parameters at the condensate outlet pipe of a vacuum heat pipe heat exchanger through a data acquisition module. A fault mode intelligent judgment module identifies fault modes, including flue gas leakage, external water acidification, and uncertain states, enabling intelligent identification of acid corrosion. A multi-level linkage protection module automatically executes multi-level protection actions such as isolation, neutralization, and dilution based on the determined fault modes, achieving intelligent protection against flue gas corrosion. A self-testing module continuously monitors condensate parameters until the condensate quality returns to normal standards, at which point it sends a stop signal to the multi-level linkage protection module, ending its personalized protection. If the water quality does not return to normal standards within a preset time, an audible and visual alarm is triggered, improving the intelligence and timeliness of early warning. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0024] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figure 1 A smart control method for flue gas corrosion prevention based on the coupling of vacuum heat pipes and condensate includes the following steps: S1: The data acquisition module collects condensate parameters at the condensate outlet pipe of the vacuum heat pipe heat exchanger; the condensate parameters include the real-time pH value, conductivity and chloride ion concentration of the condensate; S2: The fault mode intelligent judgment module determines the fault mode based on the collected condensate parameters. The fault modes include: flue gas leakage, external water acidification, and uncertain state. Fault mode determination based on collected condensate parameters includes the following steps: S2.1: Calculate the rate of change of conductivity and the rate of change of chloride ion concentration. The relevant expressions are as follows: The expression for the rate of change of conductivity is as follows:

[0026] in, This indicates the amount of condensate at the current moment. The rate of change of conductivity; This indicates the amount of condensate at the current moment. The electrical conductivity; This indicates the amount of condensate at the current moment. Previous time period The electrical conductivity; The expression for the rate of change of chloride ion concentration is as follows:

[0027] in, This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration; This indicates the amount of condensate at the current moment. Chloride ion concentration; This indicates the amount of condensate at the current moment. Previous time period Chloride ion concentration; S2.2: Determine the fault mode, specifically: when and and At this time, the fault mode is determined to be flue gas leakage. This indicates the amount of condensate at the current moment. pH value, This indicates the acid etching warning threshold. This indicates the amount of condensate at the current moment. The rate of change of conductivity, Indicates the threshold for a sudden increase in conductivity. This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration. This indicates the steady-state threshold of chloride ion concentration; when and When the fault mode is determined to be external water acidification, the fault mode is determined to be an uncertain state in all other cases. When a vacuum heat pipe perforates or cracks, flue gas (containing acidic gases such as SO2, SO3, and SO3, as well as a small amount of fly ash) enters the condensate side, where the acidic gases dissolve to form H2O. + HSO3 This leads to a rapid drop in pH; simultaneously, soluble salts (such as ammonium salts and sulfates) and metal corrosion products in the flue gas significantly increase the conductivity of water, but the chloride ion concentration in the flue gas is usually low, so Cl... The changes are not obvious, therefore, when and and At the same time, both points to flue gas leakage; external makeup water acidification usually stems from: failure of the pretreatment system (such as sodium bed, reverse osmosis), resulting in Cl in the raw water. Exceeding the standard; acid leakage from the acid regeneration cation bed, leading to H+ + and Cl Simultaneously, they enter the system; at this time, as the pH decreases, Cl... The concentration will increase significantly (because Cl in tap water and industrial water) It is the main anion), while the conductivity changes relatively slowly (because Cl... Although its molar conductivity is high, its overall ionic strength change is not as drastic as that of flue gas leakage. Therefore, when and When both of the above typical conditions are not met, the fault mode intelligent judgment module automatically determines that the fault mode is uncertain and triggers a temporary dilution action to avoid misoperation such as direct addition of alkali. S3: The multi-level linkage protection module performs personalized protection based on the determined fault modes; The multi-level linkage protection module includes a heat pipe isolation unit, an alkaline neutralization unit, and a transient dilution unit. The heat pipe isolation unit performs protection when the fault mode is determined to be flue gas leakage. Specifically, when the fault mode is flue gas leakage, the heat pipe isolation unit condensate inlet valve and outlet valve are closed, and the flue gas side bypass valve is opened. The alkaline neutralization unit performs protection when the fault mode is determined to be external water acidification. Specifically, when the fault mode is external water acidification, the alkaline neutralization unit controls the amount of neutralizing agent added through a metering pump, as shown in the following expression:

[0028] in, Indicates the current time The target dosing rate of the neutralizing agent; Indicates the adjustment coefficient; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. pH value; This indicates the amount of condensate at the current moment. Volumetric flow rate; This indicates the density of condensate; Indicates the molar mass of the neutralizing agent; Indicates the molar mass of a hydrogen ion; This indicates taking the maximum value; This directly reflects the degree to which the current water quality deviates from the target safety value; the greater the deviation (i.e., the stronger the acidity), the higher the required rate of neutralizing agent dosage, multiplied by... This reflects the dilution effect; under the same pH deviation, a larger condensate flow rate means a larger total amount of acidic ions need to be neutralized, thus requiring a higher dosing rate to raise the overall pH to the target value. Convert the volumetric flow rate and mass concentration requirements into the theoretical molar requirements of the neutralizing agent. It achieves precise dosing based on chemical equivalent ratio adjustment, avoiding the waste or insufficient neutralization caused by traditional timed or flow-rate alkali dosing, and provides a reliable and economical active protection method for bidirectional corrosion prevention of condensate systems. The transient dilution unit performs protection when the fault mode is determined to be an uncertain state. Specifically, when the fault mode is an uncertain state, and At that time, among them, This is the acid corrosion hazard threshold. This is the acid etching warning threshold. For condensation water at the current moment The pH value is controlled by a water pump to regulate the condensate flow rate. The relevant expression is as follows:

[0029]

[0030] in, Indicates the current time The target flow rate of condensate; This indicates the condensate flow rate under normal operating conditions. Indicates the acid etching warning threshold; This indicates the amount of condensate at the current moment. pH value; Indicates the acid corrosion hazard threshold; The maximum additional flow coefficient; Indicates the duration of the target traffic; This indicates the total volume of the condensate system; Indicates the adjustment coefficient; This formula achieves a linear positive correlation between the increase in flow rate and the severity of acidity; molecule This indicates the deviation between the current pH value and the acid corrosion warning threshold. The larger the deviation (i.e., the stronger the acidity), the higher the required dilution. The denominator represents the difference between the current pH value and the acid corrosion warning threshold. This serves as a normalization function for the allowable pH decrease range; coefficient The maximum flow rate increase is limited to avoid excessive flow rate impacting the pump and pipeline; therefore, this formula ensures that: when the pH is just below the warning threshold, the flow rate is increased only slightly; when the pH is close to the danger threshold, the flow rate is significantly diluted to the upper limit, thus achieving precise control of on-demand dilution. This represents the time required to completely replace all the water in the entire condensate system. S4: The self-test module continuously monitors the condensate parameters until the condensate water quality returns to the normal standard. It then sends a stop signal to the multi-level linkage protection module to end its personalized protection. If the water quality does not return to the normal standard within the preset time, an audible and visual alarm will be triggered. The standards for water quality restoration are as follows:

[0031] in, For condensation water at the current moment pH value; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. The rate of change of conductivity; This represents the rate of change of standard conductivity.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smart control method for flue gas corrosion prevention based on the coupling of vacuum heat pipes and condensate, characterized in that: Includes the following steps: S1: The data acquisition module collects condensate parameters at the condensate outlet pipe of the vacuum heat pipe heat exchanger; S2: The fault mode intelligent judgment module determines the fault mode based on the collected condensate parameters. The fault modes include: flue gas leakage, external water acidification, and uncertain state. S3: The multi-level linkage protection module performs personalized protection based on the determined fault modes; S4: The self-test module continuously monitors the condensate parameters until the condensate water quality returns to the normal standard. It then sends a stop signal to the multi-level linkage protection module to end its personalized protection. If the water quality does not return to the normal standard within the preset time, an audible and visual alarm will be triggered.

2. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 1, characterized in that: The S1 condensate parameters include the real-time pH value, conductivity, and chloride ion concentration of the condensate.

3. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 2, characterized in that: The S2 method determines the fault mode based on the collected condensate parameters, including the following steps: S2.1: Calculate the rate of change of conductivity and the rate of change of chloride ion concentration; S2.2: Determine the fault mode, specifically: when and and At this time, the fault mode is determined to be flue gas leakage. This indicates the amount of condensate at the current moment. pH value, This indicates the acid etching warning threshold. This indicates the amount of condensate at the current moment. The rate of change of conductivity, Indicates the threshold for a sudden increase in conductivity. This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration. This indicates the steady-state threshold of chloride ion concentration; when and When the fault mode is determined to be external water acidification, the fault mode is determined to be an uncertain state in all other cases.

4. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 3, characterized in that: The expression for the rate of change of conductivity in S2.1 is as follows: in, This indicates the amount of condensate at the current moment. The rate of change of conductivity; This indicates the amount of condensate at the current moment. The electrical conductivity; This indicates the amount of condensate at the current moment. Previous time period The electrical conductivity.

5. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 3, characterized in that: The expression for the rate of change of chloride ion concentration in S2.1 is as follows: in, This indicates the amount of condensate at the current moment. The rate of change in chloride ion concentration; This indicates the amount of condensate at the current moment. Chloride ion concentration; This indicates the amount of condensate at the current moment. Previous time period The chloride ion concentration.

6. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 3, characterized in that: The S3 multi-level linkage protection module includes a leak-isolation heat pipe unit, an alkaline neutralization unit, and a transient dilution unit. The leak-isolation heat pipe unit performs protection when the fault mode is determined to be flue gas leakage. Specifically, when the fault mode is flue gas leakage, the leak-isolation heat pipe unit condensate inlet valve and outlet valve are closed, and the flue gas side bypass valve is opened.

7. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 6, characterized in that: The alkaline neutralization unit performs protection when the fault mode is determined to be external water acidification. Specifically, when the fault mode is external water acidification, the alkaline neutralization unit controls the amount of neutralizing agent added via a metering pump, as shown in the following expression: in, Indicates the current time The target dosing rate of the neutralizing agent; Indicates the adjustment coefficient; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. pH value; This indicates the amount of condensate at the current moment. Volumetric flow rate; This indicates the density of condensate; Indicates the molar mass of the neutralizing agent; Indicates the molar mass of a hydrogen ion; This indicates taking the maximum value.

8. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 7, characterized in that: The transient dilution unit performs protection when the fault mode is determined to be an uncertain state, specifically: when the fault mode is an uncertain state, and At that time, among them, This is the acid corrosion hazard threshold. This is the acid etching warning threshold. For condensation water at the current moment The pH value is controlled by a water pump to regulate the flow rate of condensate.

9. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 8, characterized in that: The relevant expression for controlling the condensate flow rate by the water pump is as follows: in, Indicates the current time The target flow rate of condensate; This indicates the condensate flow rate under normal operating conditions. Indicates the acid etching warning threshold; This indicates the amount of condensate at the current moment. pH value; Indicates the acid corrosion hazard threshold; The maximum additional flow coefficient; Indicates the duration of the target traffic; This indicates the total volume of the condensate system; This represents the adjustment coefficient.

10. The intelligent control method for flue gas corrosion prevention based on the coupling of vacuum heat pipe and condensate as described in claim 8, characterized in that: The standards for S4 water quality restoration are as follows: in, For condensation water at the current moment pH value; Indicates the standard pH value of condensate; This indicates the amount of condensate at the current moment. The rate of change of conductivity; This represents the rate of change of standard conductivity.

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