Chemical cleaning and maintaining device for boiler and using method of chemical cleaning and maintaining device

Abstract

The invention relates to the technical field of boiler cleaning and discloses a boiler chemical cleaning and maintaining device and a using method thereof.The boiler chemical cleaning and maintaining device comprises a boiler and a control valve II communicating with the boiler through a pipeline, the control valve II communicates with a water pump I through a pipeline, and the water pump I communicates with a three-way valve through a pipeline; the three-way valve is respectively communicated with the saline water tank and the pickling agent tank through pipelines, and water scale in the boiler is softened by saline water, so that the cleaning effect of the pickling agent is enhanced. According to the equipment, the strength and compactness of scale are greatly reduced through dual pretreatment of salt water softening pretreatment and penetrating agent deep permeation, salt water enables crystal lattices of the scale to be relaxed through osmotic pressure and ion exchange, the penetrating agent penetrates into a scale layer through micro cracks generated by temperature difference circulation and negative pressure suction, and optimal reaction conditions are created for follow-up acid pickling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boiler cleaning, in particular to a boiler chemical cleaning and maintenance device and a use method thereof. BACKGROUND

[0002] In the field of industrial production, as the core equipment of heat supply, the calcium and magnesium ions in the water are easy to deposit and form scale on the heating surface during long-term operation. The thermal conductivity of scale is only a few tenths of that of metal, which can greatly reduce the thermal efficiency of the boiler and increase fuel consumption. At the same time, the accumulation of scale may cause local overheating of the heating surface, leading to deformation, corrosion and even burst of the boiler pipe, which seriously threatens the safe operation of the equipment. Therefore, regular chemical cleaning and maintenance of the boiler is a key process to ensure its stable operation.

[0003] The current mainstream chemical cleaning technology for boilers is mainly direct pickling, that is, through chemical reaction of acid pickling agent (such as hydrochloric acid, citric acid, etc.) with scale, the scale is dissolved and removed. However, this technology has significant defects in practical application: on the one hand, for the dense and hard scale formed during long-term operation, the acid pickling agent is difficult to penetrate quickly, and the cleaning time needs to be extended or the acid concentration needs to be increased, which not only increases the consumption and cost of chemicals, but also accelerates the corrosion of the inner wall of the boiler metal, shortening the service life of the equipment; on the other hand, during the pickling process, the surface layer of the scale reacts with the acid first to form a dissolved layer, which hinders the contact between the acid pickling agent and the deep layer of the scale, resulting in incomplete cleaning and easy residual scale becoming the core of subsequent scaling, shortening the cleaning cycle.

[0004] The existing cleaning technology also has the problems of low utilization rate of chemicals and high environmental pressure; the penetrant and acid pickling agent are easy to volatilize or be discharged with waste liquid during use, which not only causes waste of chemicals, but also increases the cost of waste water treatment; at the same time, the traditional cleaning process relies on manual control of valves and adjustment of parameters, and has low automation degree, complicated operation and easy fluctuation of cleaning effect due to human error, which is difficult to adapt to the high efficiency, safety and environmental protection maintenance requirements of modern industrial boilers. Therefore, the present application provides a boiler chemical cleaning and maintenance device and a use method thereof. SUMMARY

[0005] In view of the above-mentioned deficiencies of the prior art, the present application provides a boiler chemical cleaning and maintenance device and a use method thereof, which improves the cleaning efficiency of the boiler from the aspects of cleaning efficiency, effect, utilization rate of chemicals and equipment adaptability, etc. through the core design of the processes of brine softening, temperature difference negative pressure penetration, acid pickling and cleaning, and penetrant recovery.

[0006] The present application provides the following technical solutions: a boiler chemical cleaning and maintenance device, comprising a boiler and a control valve II connected to the boiler through a pipeline, the control valve II is connected to a water pump I through a pipeline, the water pump I is connected to a three-way valve through a pipeline, the three-way valve is connected to a brine tank and an acid pickling agent tank through pipelines respectively, and the brine is used to soften the scale in the boiler and enhance the cleaning effect of the acid pickling agent; The water outlet at the bottom of the boiler is connected to a control valve III through a pipeline, and the control valve III is used to discharge the liquid in the boiler; The boiler is connected to a control valve I through a pipeline, the control valve I is connected to an atomizer exhaust port through a pipeline, an atomizer air inlet is connected to a heater through a pipeline, the heater is connected to a pressure regulating valve through a pipeline, the pressure regulating valve is connected to a nitrogen tank through a pipeline, a liquid inlet of the atomizer is connected to a flow valve through a pipeline, the flow valve is connected to a water pump II through a pipeline, and the water pump II is connected to a penetrant tank through a pipeline; The heated nitrogen gas is used to guide the water mist of the penetrant into the boiler, the inside of the boiler is heated, the scale is heated and adsorbed to the penetrant, the penetration effect of the penetrant is enhanced, then the heating function of the heater is turned off, the normal-temperature nitrogen gas carrying the penetrant is guided into the boiler to cool the boiler, the temperature change promotes the scale to crack, the penetration effect of the penetrant is enhanced, reaction conditions are provided for the pickling process, and the pickling efficiency is improved; The exhaust port of the boiler is connected to a dehumidifier through a pipeline, the dehumidifier is connected to a pressure relief valve and a pressure gauge through pipelines respectively, the pressure gauge is connected to a vacuum pump through a pipeline, the pressure relief valve is opened to make the internal pressure of the boiler normal, the penetrant is conveniently guided into the boiler, the pressure relief valve is closed, and the vacuum pump is used to draw the boiler into a negative pressure state, so that the penetrant is promoted to be absorbed into the scale and reaction conditions are provided for the pickling process.

[0007] Preferably, the dehumidifier and the penetrant tank are connected through a recovery system, the penetrant condensed and recovered by the dehumidifier is guided into the penetrant tank for reuse.

[0008] Preferably, the main components of the penetrant are high-efficiency penetrant, wetting dispersant, metal ion blocking agent, pre-corrosion inhibitor and carrier solvent.

[0009] A use method of the boiler chemical cleaning and maintenance device, and the specific operation is as follows: S1, open the control valve II, start the water pump I, switch the three-way valve to the pipeline connected to the brine tank, make the brine establish a circulation in the boiler, circulate the brine solution in the boiler for 4-8 hours, and finally open the control valve III to empty the brine solution; S2, close control valve II and control valve III, open control valve I, switch the system to the penetrant treatment process, open the pressure regulating valve, lead out nitrogen from the nitrogen tank, start the heater, heat the nitrogen to 80-100 DEG C, start water pump II, adjust the flow valve, transport the liquid medicine in the penetrant tank to the atomizer, at the same time, the heated nitrogen enters the atomizer, atomizes the liquid medicine into micron-level fine droplets, forms a high-temperature aerosol, and is introduced into the boiler through the control valve I; continue to introduce for 30-60 minutes, so that the inner wall of the boiler is uniformly heated to about 60-70 DEG C; at this temperature, the surface activity of the scale is enhanced, the high-efficiency adsorption of the atomized penetrant is formed on the scale surface and shallow layer, and a high-concentration medicament reserve is formed on the scale surface and shallow layer; S3, close the heater, make the nitrogen entering the atomizer into normal temperature, continue to atomize and introduce the penetrant, realize 2-3 temperature difference cycles of the inner wall of the boiler between 60-70 DEG C and 30-40 DEG C by controlling the switching time of the cold and hot nitrogen; in this process, the difference between the metal and the scale thermal expansion coefficient is utilized to produce alternating thermal stress, so that the micro-crack network is generated in the scale; S4, keep the normal temperature nitrogen and the atomization and introduction of the penetrant; open the dehumidifier pipeline connected to the boiler exhaust port, ensure that the pressure relief valve is closed, start the vacuum pump, and slowly reduce the pressure in the boiler to a micro-negative pressure state by observing the pressure gauge; in the negative pressure environment, the atomized penetrant is more strongly sucked into the fresh micro-cracks and pores generated in the temperature difference cycle of the scale, and depth preposition is realized; finally, the vacuum pump is closed, the pressure relief valve is slowly opened, the pressure in the boiler is restored to normal pressure; the water pump II, the flow valve and the pressure regulating valve are closed, and the liquid medicine and the nitrogen supply are stopped; S5, close control valve I, open control valve II, switch the three-way valve to the pipeline connected to the acid pickling agent tank, start water pump I, and inject the acid pickling agent into the boiler and establish circulation; the acid liquid is heated to the process required temperature by using the boiler itself or external heat source, and after the acid pickling is completed, it is emptied through the control valve III.

[0010] Compared with the prior art, the present application has the following beneficial effects: (1) The equipment is preprocessed by salt water softening and deeply penetrated by the penetrant, so that the scale strength and density are greatly reduced, the salt water is relaxed by the osmotic pressure and ion exchange effect, the penetrant is deeply sucked into the scale layer by the micro-cracks generated by the temperature difference cycle and the negative pressure, and the optimal reaction conditions are created for the subsequent acid pickling; compared with the traditional direct acid pickling method, the reaction rate of the acid pickling agent and the scale is significantly improved, the scale can be completely removed without long-time circulation, and at the same time, the whole process is automatically controlled through the cooperation of the valves and the pump body, the manual intervention link is reduced, the boiler cleaning and maintenance cycle is greatly shortened, and the maintenance demand of the continuous operation of the industrial boiler is adapted.

[0011] (2) The application solves the pain points of traditional cleaning that is difficult to handle deep and dense scale through temperature difference pre-cracking and negative pressure penetration. The temperature difference cycle formed by the alternating introduction of high temperature and normal temperature nitrogen gas utilizes the difference in thermal expansion coefficient between metal and scale to generate alternating thermal stress, which promotes the formation of uniform micro-cracks in the scale. The negative pressure environment further sucks the atomized penetrating agent into the deep cracks, completely weakening the bonding force between the scale and the inner wall of the boiler. During the pickling stage, the pickling agent can quickly penetrate along the micro-cracks and uniformly act on every scale, avoiding the problem of surface removal and deep residual scale in traditional cleaning, ensuring that there is no scale residue on the inner wall of the boiler, and reducing equipment failures and heat efficiency loss caused by scale accumulation during subsequent operation.

[0012] (3) The penetrating agent atomization pretreatment module uses nitrogen gas atomization to form micron-sized aerosol, which greatly increases the contact area with the scale, and a small amount of agent can achieve deep penetration, avoiding the waste of agent caused by traditional liquid spraying. On the other hand, the dehumidifier and the recovery system cooperate to condense and recover the atomized penetrating agent from the boiler exhaust gas, and return it to the penetrating agent tank for reuse, significantly reducing the cost of agent consumption. At the same time, the efficient use and recovery of the agent reduce the amount of waste liquid discharge, reduce the environmental pressure of subsequent wastewater treatment, and meet the requirements of green industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The system flowchart of the application DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the technical scheme of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits the detailed description of known functions and known components to avoid unnecessary confusion of the concept of the present invention.

[0015] Please refer to Figure 1 The device takes the boiler as the cleaning object, and is composed of a liquid supply module, a penetrating agent atomization pretreatment module, a negative pressure and dehumidification recovery module, and control valves. Each module is precisely linked through a sealed pipeline to form a complete link of "liquid delivery - pretreatment - cleaning - waste liquid discharge - agent recovery".

[0016] The boiler, as the core cleaning cavity, has its pipeline system connected with the liquid supply module and the penetrating agent atomization pretreatment module. The water inlet end of the boiler is connected with control valve II through a pipeline, control valve II is connected with water pump I through a pipeline, the input end of water pump I is connected with a brine tank and a pickling agent tank through a three-way valve to realize the switching supply of brine and pickling agent. The water outlet at the bottom of the boiler is connected with control valve III through a pipeline for discharging the waste liquid after cleaning.

[0017] The permeating agent atomization pretreatment module is connected with the boiler through independent pipelines: the air inlet end of the boiler is connected with control valve I through a pipeline, the input end of control valve I is connected with the exhaust port of the atomizer, the air inlet port of the atomizer is connected with a heater and a pressure regulating valve in sequence through a pipeline, the pressure regulating valve is connected with a nitrogen tank to form a nitrogen gas delivery channel; the liquid inlet port of the atomizer is connected with a flow valve and a water pump II in sequence through a pipeline, the water pump II is connected with the permeating agent tank to form a permeating agent delivery channel.

[0018] The negative pressure and dehumidification recovery module is connected with the exhaust end of the boiler; the exhaust port of the boiler is connected with a dehumidifier through a pipeline, the output end of the dehumidifier is connected with a pressure relief valve and a pressure gauge respectively, the other end of the pressure gauge is connected with a vacuum pump through a pipeline to realize the pressure regulation and monitoring of the inside of the boiler; the dehumidifier is connected with the permeating agent tank through a recovery system to form a permeating agent condensation recovery loop, and the connection positions of the pipelines are all designed to be sealed to avoid gas leakage and drug liquid evaporation.

[0019] The core function of the drug liquid supply module is to provide brine and pickling agent for the boiler, and the quick switching of the two kinds of drugs is realized through a three-way valve, and the specific implementation is as follows: The three interfaces of the three-way valve are connected with a water pump I, a brine tank and a pickling agent tank through sealed pipelines respectively, the water pump I is connected with the water inlet end of the boiler through control valve II to form a switchable circulation loop. When the brine softening treatment is needed, the three-way valve is switched to the pipeline connected with the brine tank, the water pump I is started, the brine is injected into the boiler through control valve II to form a circulation flow channel in the boiler, and is discharged through control valve III after the softening is completed; when pickling is needed, the three-way valve is switched to the pipeline connected with the pickling agent tank, the water pump I is started again to inject the pickling agent into the boiler to establish circulation and realize the removal of scale by pickling. The whole switching process is controlled by control valve II and the three-way valve to ensure that there is no leakage when the pipeline is switched and the two kinds of drugs are not mixed and contaminated.

[0020] The permeating agent atomization pretreatment module realizes the pre-cracking and penetration of scale through the mode of "high-temperature nitrogen gas atomization-normal temperature nitrogen gas cooling-temperature difference circulation" and atomized permeating agent, and the specific implementation is as follows: The atomizer is a gas-liquid mixed atomization structure, the air inlet port of which receives nitrogen gas from the heater, and the liquid inlet port of which receives permeating agent from the permeating agent tank, and the high-speed flow of the nitrogen gas disperses the permeating agent to form micron-sized aerosol. The heater is installed between the nitrogen tank and the atomizer, and can heat the nitrogen gas after being electrified, the heated nitrogen gas enters the atomizer to mix with the permeating agent to form high-temperature aerosol; after the heater is turned off, normal temperature nitrogen gas directly enters the atomizer to form normal temperature aerosol, and the start and stop of the heater are controlled to realize the alternate introduction of high-temperature and normal temperature aerosols.

[0021] A pressure regulating valve is installed between the nitrogen tank and the heater to regulate the delivery pressure of nitrogen, ensuring the stability of the gas-liquid mixing ratio in the atomizer and the uniformity of the aerosol particle size. A flow valve is installed between the water pump II and the atomizer to regulate the delivery amount of the penetrant, so that the penetrant and nitrogen form an appropriate mixing concentration, ensuring the atomization effect. Control valve I is used to control the introduction and cutoff of the atomized aerosol. It is opened when the penetrant is pre-treated and closed when switching to other processes, achieving pipeline isolation.

[0022] The negative pressure and dehumidification recovery module realizes deep penetration and recycling of the penetrant through vacuum pumping by a vacuum pump and condensation recovery by a dehumidifier. The specific implementation is as follows: The dehumidifier is a condensation type recovery structure, and its input end is connected to the boiler exhaust port. It can cool the gas discharged from the boiler to condense the atomized penetrant into a liquid state. The output end of the dehumidifier has two paths: one is connected to a pressure relief valve for regulating the internal pressure of the boiler, which is opened to maintain normal pressure under normal conditions and closed when negative pressure is drawn; the other is connected to a vacuum pump through a pressure gauge, which is used to monitor the internal pressure of the boiler in real time. The vacuum pump can draw the boiler to a micro-negative pressure state after starting.

[0023] The recovery system is a sealed pipeline structure, with one end connected to the condensate outlet of the dehumidifier and the other end connected to the liquid return port of the penetrant tank. The penetrant recovered by the dehumidifier is returned to the penetrant tank through the pipeline, realizing recycling and avoiding waste of the penetrant and environmental pollution.

[0024] The main components of the penetrant are high-efficiency penetrant, wetting dispersant, metal ion blocking agent, pre-corrosion inhibitor, and carrier solvent.

[0025] The high-efficiency penetrant greatly reduces the surface tension of the liquid, enabling it to quickly wet the scale surface and penetrate deep into the interior along the capillary. Under negative pressure, this "wetting-spreading-penetration" process is greatly accelerated.

[0026] The wetting dispersant assists the penetrant in preventing small scale particles that have been penetrated from re-aggregating and blocking the opened channels, maintaining the permeation path unobstructed.

[0027] The metal ion blocking agent combines with a small amount of calcium, magnesium, and iron ions that may have been dissolved in the scale in advance to form a soluble complex, preventing them from precipitating and blocking the newly opened micropores.

[0028] The pre-corrosion inhibitor can quickly form a film to provide immediate protection against pitting corrosion during subsequent main cleaning as soon as fresh metal surfaces are exposed during the penetration process of the liquid.

[0029] Through the penetrant, the interior of the scale is transformed into a loose structure full of pores and cracks, and its reaction contact area is increased by tens or even hundreds of times. The acid solution can directly contact and dissolve the key components in the deepest part of the scale, greatly improving the cleaning speed.

[0030] The boiler chemical cleaning maintenance device of the application carries out boiler cleaning maintenance, and realizes efficient cleaning through the following steps.

[0031] Salt water softening pretreatment: first, close control valve I, pressure relief valve and vacuum pump, open control valve II and three-way valve to connect the pipeline of salt water tank, start water pump I, inject the salt water in the salt water tank into the boiler through the pipeline, and establish a circulating flow channel in the boiler. In the circulating process, the salt water softens the scale in the boiler through osmotic pressure and ion exchange, reduces the strength and density of the scale. After the softening treatment is completed, close water pump I and control valve II, open control valve III, and completely empty the salt water waste liquid in the boiler, completing the first step of pretreatment.

[0032] High-temperature atomized penetrant pretreatment: close control valve III, open control valve I, switch the system to the penetrant treatment process. Open the pressure regulating valve to lead out nitrogen from the nitrogen tank, start the heater to heat the nitrogen, and start water pump II at the same time. Adjust the flow valve to make the penetrant in the penetrant tank be transported to the atomizer at a set ratio. The heated nitrogen enters the atomizer, fully mixes with the penetrant, atomizes the penetrant into high-temperature aerosol, and continuously introduces the high-temperature aerosol into the boiler through control valve I. The high-temperature aerosol not only heats the inner wall of the boiler, but also enhances the surface activity of the scale, efficiently absorbs the atomized penetrant, and forms a drug reserve layer on the surface and shallow layer of the scale.

[0033] Temperature difference cycle pre-cracking treatment: after the high-temperature atomized penetration is completed, close the heater to switch the nitrogen entering the atomizer to normal temperature, and continue to maintain the atomization and introduction of the penetrant. By controlling the start-stop interval of the heater, the temperature of the inner wall of the boiler in different temperature intervals is alternately changed, the difference in thermal expansion coefficients between the metal and the scale is utilized to generate alternating thermal stress in the scale, and the scale is promoted to form a uniform micro-crack network to create a channel for the deep penetration of the penetrant.

[0034] Negative pressure deep penetration treatment: maintain the atomization and introduction state of the normal temperature nitrogen and the penetrant, open the pipeline connecting the dehumidifier and the boiler, and ensure that the pressure relief valve is closed. Start the vacuum pump, monitor the pressure change in the boiler by observing the pressure gauge, and slowly draw the inside of the boiler to a micro-negative pressure state. Under the action of negative pressure, the atomized penetrant is strongly sucked and penetrates into the scale layer along the micro-cracks and pores of the scale, realizing the deep preposition of the penetrant and further weakening the bonding force between the scale and the inner wall of the boiler. After the penetration is completed, close the vacuum pump, slowly open the pressure relief valve to restore the pressure in the boiler to normal pressure, then close water pump II, flow valve and pressure regulating valve to stop the supply of penetrant and nitrogen, and close control valve I.

[0035] The acid pickling deep cleaning: close the control valve I and the pressure relief valve, open the control valve II, switch the three-way valve to the pipeline connected with the acid pickling agent tank, start the water pump I, inject the acid pickling agent in the acid pickling agent tank into the boiler and establish a circulating flow channel. The acid liquid can be heated by using the heat source of the boiler itself or an external heat source to improve the acid pickling reaction efficiency. Since the scale has been treated by brine softening, deep penetration of the penetrating agent and pre-cracking, the acid pickling agent can quickly and uniformly react with the scale during the acid pickling process, greatly improving the rate and uniformity of acid pickling and thoroughly removing the scale on the inner wall of the boiler. After the acid pickling is completed, the water pump I is closed and the control valve III is opened to empty the acid pickling waste liquid, and the whole cleaning and maintenance process is completed.

[0036] The above examples are only exemplary embodiments of the present application and are not intended to limit the present application. The scope of protection of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A boiler chemical cleaning and maintenance device, characterized in that: It includes a boiler and a control valve II connected to the boiler via a pipe. The control valve II is connected to a water pump I via a pipe. The water pump I is connected to a three-way valve via a pipe. The three-way valve is connected to a brine tank and an acid pickling agent tank via pipes respectively. The brine is used to soften the scale in the boiler and enhance the cleaning effect of the acid pickling agent. The water outlet at the bottom of the boiler is connected to control valve III via a pipe, and the liquid in the boiler is discharged through control valve III; The boiler is connected to control valve I via a pipeline, and control valve I is connected to the atomizer exhaust port via a pipeline. The atomizer air inlet is connected to the heater via a pipeline. The heater is connected to the pressure regulating valve via a pipeline. The pressure regulating valve is connected to the nitrogen tank via a pipeline. The liquid inlet of the atomizer is connected to the flow valve via a pipeline. The flow valve is connected to water pump II via a pipeline. Water pump II is connected to the permeate tank via a pipeline. Heated nitrogen gas is used to atomize the penetrant into a water mist and introduce it into the boiler. This heats the boiler interior, causing the scale to absorb the penetrant and enhancing its penetration effect. Then, the heater is turned off, and room-temperature nitrogen gas carrying the penetrant is introduced into the boiler to cool it down. The temperature change causes the scale to crack, further enhancing the penetrant's penetration effect and providing reaction conditions for the acid washing process, thus improving acid washing efficiency. The boiler's exhaust port is connected to a dehumidifier via a pipe. The dehumidifier is connected to a pressure relief valve and a pressure gauge via pipes. The pressure gauge is connected to a vacuum pump via a pipe. When the pressure relief valve is opened, the internal air pressure of the boiler is normalized, facilitating the introduction of the penetrant. When the pressure relief valve is closed, the vacuum pump draws the boiler into a negative pressure state. Under negative pressure, the penetrant is drawn into the scale, providing reaction conditions for the acid washing process.

2. The boiler chemical cleaning and maintenance device according to claim 1, characterized in that: The dehumidifier and the permeate tank are connected by a recovery system, which introduces the permeate recovered by the dehumidifier into the permeate tank for reuse.

3. The boiler chemical cleaning and maintenance device according to claim 1, characterized in that: The main components of the penetrant are high-efficiency penetrant, wetting and dispersing agent, metal ion blocking agent, pre-corrosion inhibitor and carrier solvent.

4. A method of using a boiler chemical cleaning and maintenance device, characterized in that, The boiler chemical cleaning and maintenance device according to any one of claims 1-3 is operated as follows: S1. Open control valve II, start water pump I, switch the three-way valve to the pipeline connecting to the brine tank, so that the brine can circulate in the boiler. Circulate the brine solution in the boiler for 4-8 hours, and finally open control valve III to drain the brine solution. S2. Close control valves II and III, open control valve I, switch the system to the penetrant treatment process, open the pressure regulating valve, draw nitrogen from the nitrogen tank, start the heater, heat the nitrogen to 80-100℃, start water pump II, adjust the flow valve, and deliver the liquid in the penetrant tank to the atomizer. At the same time, the heated nitrogen enters the atomizer, atomizing the liquid into micron-sized fine droplets to form a high-temperature aerosol, which is then introduced into the boiler through control valve I. Continue heating for 30-60 minutes to ensure the boiler's inner wall is evenly heated to approximately 60-70°C. S3. Turn off the heater to bring the nitrogen gas introduced into the atomizer to room temperature, continue atomization and introduce the penetrant. By controlling the switching time of hot and cold nitrogen gas, 2-3 temperature difference cycles between 60-70℃ and 30-40℃ are achieved on the inner wall of the boiler. S4. Maintain atomized nitrogen and penetrant at room temperature; open the dehumidifier pipe connected to the boiler exhaust port and ensure the pressure relief valve is closed. Start the vacuum pump and, by observing the pressure gauge, slowly reduce the internal pressure of the boiler to a slightly negative pressure state; finally, turn off the vacuum pump, slowly open the pressure relief valve, and allow the internal pressure of the boiler to return to normal pressure; turn off water pump II, flow valve, and pressure regulating valve to stop the supply of chemicals and nitrogen. S5. Close control valve I, open control valve II, switch the three-way valve to the pipeline connecting to the pickling agent tank, start water pump I, inject pickling agent into the boiler and establish circulation; use the boiler itself or an external heat source to heat the acid solution to the required process temperature, and after pickling is completed, drain it through control valve III.

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