Method for solving scaling problem of steelmaking dry dedusting system

Abstract

The invention discloses a method for solving scaling of a steelmaking dry dust removal system, which comprises the following steps of: forming 0.8-1.2 MPa dynamic medium-pressure nitrogen flow by utilizing surplus high-purity nitrogen of an oxygen making unit through a graded pulse depressurization technology, and enhancing scaling stripping; a self-adaptive pressure compensation special pipe conveying system is adopted, it is ensured that the terminal pressure ranges from 0.6 MPa to 1.0 MPa, and distribution is optimized; a steam spray gun is replaced by a self-spinning nitrogen vortex spray gun, composite spray is formed by the self-spinning nitrogen vortex spray gun and 5%-10% of deionized water through the vortex effect, and the pressure of a nozzle is 0.6-0.8 MPa; the nitrogen pulse frequency and the spray gun rotating speed are fed back and regulated through the ultrasonic sensor, the scaling speed is smaller than or equal to 80 mm / 6 months, and steam consumption is reduced to zero. According to the invention, the scaling speed is reduced by more than 30%, the service life of the spray gun is prolonged to be more than or equal to 1.5 years, the proportion of coarse ash is increased to 25-30%, the steam cost is saved per year by 13500,000 yuan, the nitrogen sales income is increased by about 2365,000 yuan, and the total benefit is remarkable. The method is energy-saving, environment-friendly and high in resource utilization rate, and an efficient solution is provided for the steelmaking industry.

Description

Technical Field

[0001] The invention belongs to the technical field of compressors and relates to a method for solving scaling of a steelmaking dry dust removal system. Background Art

[0002] In the process of global industrialization, the continuous growth of energy consumption has become a common challenge faced by all industries. Especially in high-energy-consuming fields such as chemical industry, metallurgy and oxygen production, compressors, as core power equipment, often consume more than 30%-50% of production costs, becoming a key link in optimizing operational efficiency. Centrifugal nitrogen compressors are widely used in oxygen production systems, nitrogen circulation processes and gas pressurization processes in chemical production due to their high flow and high pressure characteristics. However, many nitrogen compressors in service have aging components due to their long-term design or long-term operation, and their energy consumption is significantly higher than that of modern equipment. Taking the SVK16-3S centrifugal compressor of an oxygen plant as an example, the operating power of this equipment is as high as 1560kW, which is 10%-20% higher than that of similar new models. The additional cost caused by high energy consumption exceeds one million yuan each year. This phenomenon is not an isolated case in the industrial field. Many old compressors used by enterprises generally have problems of low efficiency and serious energy waste.

[0003] In the prior art, the improvement methods for the energy consumption problem of compressors mainly include multiple directions such as adjusting operating parameters, replacing high-efficiency components and introducing control systems. First, adjusting operating parameters is a common means of energy saving. For example, by changing the guide vane opening or manually adjusting the speed, the compressor can be close to higher efficiency under specific working conditions. However, this method is limited by the aerodynamic characteristics of the original design of the equipment, and the efficiency improvement is usually only between 3% and 5%, and it is difficult to maintain a stable effect under variable working conditions (such as seasonal temperature changes or production load fluctuations). Secondly, replacing high-efficiency components (such as three-dimensional impellers) is considered to be an effective way to improve the performance of compressors. The three-dimensional impeller can significantly improve the aerodynamic efficiency by optimizing the airflow path, and some cases show that energy consumption can be reduced by 8%-10%. However, most of the existing three-dimensional impellers are standardized designs, which are difficult to accurately match nitrogen compressors of specific models or working conditions, and the replacement cost is high. For example, it may cost hundreds of thousands of yuan to purchase a set of high-efficiency impellers and their accessories, and if it involves the renewal of the entire machine, the cost will be as high as millions of yuan. In addition, compatibility issues between new components and old systems (such as insufficient installation accuracy or increased vibration) may also cause the transformation effect to be less than expected.

[0004] On the other hand, variable frequency control technology (Variable Frequency Drive, VFD) has been widely used in the field of compressor energy saving in recent years. By adjusting the motor speed to match the actual load demand, variable frequency control can effectively reduce energy consumption, especially under low load conditions. Industrial practice shows that the energy consumption of some compressors equipped with frequency converters can be reduced by 5%-15%. However, the existing frequency conversion control schemes are mostly based on a single parameter (such as flow or pressure) for adjustment, lacking a comprehensive analysis of multi-condition characteristics and environmental factors (such as temperature and humidity changes), resulting in large fluctuations in energy-saving effects in actual operation. In addition, the installation and maintenance costs of the frequency converter itself are high. If it is not coordinated and optimized with the core components of the equipment (such as the impeller), its energy-saving potential is difficult to fully realize.

[0005] In addition to the above methods, there are also some comprehensive transformation solutions on the market, such as combining parameter adjustment with component replacement, or optimizing the operating status by adding a monitoring system. However, these solutions often lack systematic design. For example, some transformations only replace some aging components without considering the improvement of overall aerodynamic efficiency; although other solutions introduce data collection, the collection cycle is short (such as weeks or months), which cannot fully reflect the operating characteristics of the equipment under multiple conditions throughout the year, resulting in a lack of targeted optimization measures. Taking the SVK16-3S nitrogen compressor as an example, its operating conditions vary significantly with the seasons and production needs, and traditional transformation methods are difficult to take into account the energy-saving needs of high loads and low loads. In addition, although the solution of directly replacing the whole machine can completely solve the energy consumption problem, the long downtime (usually several months) and long investment recovery period (3-5 years) pose a challenge to the continuity and economy of enterprise production.

[0006] In summary, the existing technologies have problems such as limited efficiency improvement, narrow scope of application, high cost or insufficient stability in the energy-saving transformation of nitrogen compressors. For old centrifugal nitrogen compressors, how to achieve significant energy consumption reduction through economical and efficient technical means while retaining the existing equipment foundation, while ensuring that the transformation plan is suitable for a variety of models and working conditions, has become a technical problem that needs to be solved urgently. It is in this context that the present invention is proposed, aiming to provide a systematic, data-driven energy-saving solution. Summary of the invention

[0007] In view of this, the purpose of the present invention is to solve the above-mentioned problem and provide a method for solving the scaling of the steelmaking dry dust removal system.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A method for solving scaling of a steelmaking dry dust removal system comprises the following steps:

[0010] Step 1: Utilize the surplus high-purity nitrogen from the oxygen generator of the steel plant, and use the graded pulse decompression technology to decompress the high-pressure nitrogen in stages to 0.8-1.2 MPa, forming a dynamic medium-pressure nitrogen flow with periodic pressure fluctuations to enhance the disturbance and stripping effect of the airflow on the scaling particles;

[0011] Step 2: Adopt an adaptive pressure compensation dedicated pipe delivery system to deliver the dynamic medium-pressure nitrogen flow to the steel plant dry dust removal evaporative cooler spray system. The dedicated pipe system has a built-in pressure self-sensing module to compensate the pressure in real time according to the pipeline length and flue gas load, ensuring that the terminal injection pressure is stable at 0.6-1.0MPa, and optimizing the uniformity of nitrogen distribution through the airflow deflection device;

[0012] Step 3: Replace the traditional steam spray gun with a self-spinning nitrogen vortex spray gun. The internal part of the spray gun integrates a spiral guide channel and a trace water mist premixing chamber. The nitrogen vortex effect is used to form a high-speed rotating composite spray with a trace amount of deionized water. The nozzle working pressure is controlled at 0.6-0.8MPa to peel off and inhibit scale adhesion.

[0013] Step 4: Run the spray system, use the scaling feedback control technology combined with the ultrasonic scaling thickness sensor installed on the inner wall of the evaporative cooler to monitor the scaling status in real time and adjust the nitrogen pulse frequency and vortex spray gun speed in a linked manner. Make the scaling speed less than 80mm in average thickness within 6 months, and reduce the steam consumption from 20kg / t to zero.

[0014] Furthermore, the graded pulse pressure reduction technology is implemented through a multi-stage pressure reducing valve and a pulse generator, and the nitrogen pressure fluctuation frequency is controlled at 5 to 10 Hz to enhance the impact stripping effect on scaling particles in the evaporative cooler.

[0015] Furthermore, the adaptive pressure compensation dedicated pipe delivery system includes at least one intelligent pressure compensation valve, which automatically adjusts the nitrogen pressure based on the flue gas temperature and flow changes, and the compensation range is 0.1 to 0.3 MPa.

[0016] Furthermore, the spiral guide channel of the spinning nitrogen vortex spray gun has a gradual pitch structure, and the pitch gradually changes from 5 mm at the inlet end to 2 mm at the outlet end to form an accelerating vortex and improve the spray stripping efficiency.

[0017] Furthermore, the trace water mist premixing chamber sprays deionized water through timed pulses, and the water mist spraying frequency is synchronized with the nitrogen pulse frequency to keep the water content ratio in the composite spray stable at 5% to 10%.

[0018] Furthermore, the scaling feedback control technology detects the scaling thickness once an hour through an ultrasonic sensor. When the thickness exceeds 20 mm, the nitrogen pulse frequency is automatically increased to 10-15 Hz to enhance the stripping ability.

[0019] Furthermore, the airflow deflection device adopts a porous plate structure with a pore size distribution of 0.8 to 1.2 mm, ensuring that the nitrogen injection covers the entire area of ​​the evaporative cooler cylinder wall and the banana bend.

[0020] Furthermore, a trace amount of deionized water accounts for 5% to 10% of the total spray volume.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention significantly improves the technical performance of the steelmaking dry dust removal system through an innovative combination of dynamic nitrogen pulse, adaptive pressure compensation and vortex spray technology. Compared with the scaling rate of the traditional steam atomization system of >300mm / month and the domestic advanced level of ≤100mm / 6 months, the present invention reduces the scaling rate to ≤80mm / 6 months, a reduction of more than 30%. Thanks to the stripping effect of nitrogen pulse disturbance and vortex spray, combined with ultrasonic feedback control to monitor and adjust parameters in real time, the problems of blockage and poor dust extraction are effectively solved. The life of the spray gun is extended from ≤4 months to ≥1.5 years. The spiral guide and composite spray design of the self-spinning nitrogen vortex spray gun reduce scaling adhesion and high-temperature wear, greatly reducing the replacement frequency and downtime. The proportion of coarse ash is increased from 22% to 25%~30%, reaching the domestic advanced level. The nitrogen vortex spray enhances the dust capture capacity and optimizes the overall performance of the dry dust removal system. In addition, adaptive pressure compensation and feedback control technology enable the system to dynamically adjust according to the flue gas load, overcoming the limitations of traditional static spraying and ensuring stable operation under different working conditions.

[0023] 2. The present invention has significant economic advantages in reducing costs and increasing profits. Steam consumption is reduced from 20kg / t to zero. Based on an annual output of 7.5 million tons of steel, the steam cost is saved by 13.5 million yuan / year. The annual cost of the traditional external spray gun is 4.86 million yuan (30,000 yuan / piece × 3 times / year × 18 pieces / seat × 3 seats). The annual cost of the spray gun of the present invention is reduced to 360,000 yuan (10,000 yuan / piece × 1 time / 1.5 years × 18 pieces / seat × 3 seats), saving 4.5 million yuan / year. At the same time, the excess nitrogen of the oxygen generator unit is recovered, with a flow rate of 40005000m 3 / h, 0.18 yuan / m 3 According to calculations, the annual revenue increase is about 23.65 million yuan, and the total direct economic benefits are about 41.65 million yuan. The reduction in scaling also shortens the maintenance time. Based on the estimate of saving 2 hours per maintenance, 50 maintenances per year, and 20,000 yuan per hour of downtime loss, the annual downtime loss is saved by 200.3 million yuan, further improving the capacity utilization rate. These economic benefits not only reduce the operating costs of steel mills, but also enhance the upstream and downstream synergy value through nitrogen sales, and have significant industrialization potential.

[0024] 3. The present invention has made outstanding contributions in environmental protection and resource utilization. The nitrogen consumption is only 1012m 3 / t, significantly reducing energy consumption and carbon emissions compared to traditional steam of 20kg / t, meeting green manufacturing requirements; controlled scaling eliminates smoke from the furnace mouth, improves flue gas dust extraction efficiency, ensures that environmental protection indicators meet standards, and reduces regulatory pressure. Recycling the nitrogen released by the oxygen generator unit realizes resource recycling, turning waste into treasure, and reducing nitrogen emissions by about 350 million to 440 million m3 per year 3 (4000~5000m 3 / h×8760h), which improves resource efficiency and opens up a new path for the application of nitrogen in the steelmaking industry, which has industry demonstration significance. This low-cost, high-efficiency scaling solution not only promotes the green transformation of steel mills, but also provides reference value for related technological innovation.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] A method for solving scaling of a steelmaking dry dust removal system comprises the following steps:

[0028] Step 1: Utilize the surplus high-purity nitrogen from the oxygen generator of the steel plant, and use the graded pulse decompression technology to decompress the high-pressure nitrogen in stages to 0.8-1.2 MPa, forming a dynamic medium-pressure nitrogen flow with periodic pressure fluctuations to enhance the disturbance and stripping effect of the airflow on the scaling particles;

[0029] Step 2: Adopt an adaptive pressure compensation dedicated pipe delivery system to deliver the dynamic medium-pressure nitrogen flow to the steel plant dry dust removal evaporative cooler spray system. The dedicated pipe system has a built-in pressure self-sensing module to compensate the pressure in real time according to the pipeline length and flue gas load, ensuring that the terminal injection pressure is stable at 0.6-1.0MPa, and optimizing the uniformity of nitrogen distribution through the airflow deflection device;

[0030] Step 3: Replace the traditional steam spray gun with a self-spinning nitrogen vortex spray gun. The internal part of the spray gun integrates a spiral guide channel and a trace water mist premixing chamber. The nitrogen vortex effect is used to form a high-speed rotating composite spray with a trace amount of deionized water. The nozzle working pressure is controlled at 0.6-0.8MPa to peel off and inhibit scale adhesion.

[0031] Step 4: Run the spray system, use the scaling feedback control technology combined with the ultrasonic scaling thickness sensor installed on the inner wall of the evaporative cooler to monitor the scaling status in real time and adjust the nitrogen pulse frequency and vortex spray gun speed in a linked manner. Make the scaling speed less than 80mm in average thickness within 6 months, and reduce the steam consumption from 20kg / t to zero. Specific embodiment 1

[0033] Implementation Background

[0034] The dry dust removal system of a steel plant has long been troubled by scaling of the evaporative cooler, with a scaling rate of >300mm / month, resulting in poor flue gas extraction, smoke from the furnace mouth, steam consumption of 20kg / t, and a spray gun life of only 4 months, which seriously affects production and environmental protection. Based on this, the implementation of the method of the present invention was started on April 10, 2024, combined with the technical means of the claims, to optimize the spray system, with the goal of controlling the scaling rate to ≤80mm / 6 months, and improving system performance and economic benefits.

[0035] Implementation steps

[0036] Step 1: Stepped pulse voltage reduction

[0037] Utilize the surplus high-purity nitrogen from the oxygen generator of the steel plant to install a graded pulse pressure reduction device, including a three-stage pressure reducing valve and a pulse generator. During construction on May 24, 2024, the high-pressure nitrogen (initial pressure of about 2.5MPa) will be reduced to 0.8-1.2MPa in stages, and the pulse frequency will be set at 5-10Hz to form a dynamic medium-pressure nitrogen flow. The pulse disturbance will enhance the stripping effect on scaling particles, replacing the traditional static pressure reduction method.

[0038] Step 2: Adaptive pressure compensation dedicated pipe delivery

[0039] Adopting adaptive pressure compensation dedicated pipe delivery system, a dedicated pipe (about 1.5km long) is connected from the reserved valve of oxygen production system, with built-in pressure self-sensing module and an intelligent pressure compensation valve. 3 / h total flow), real-time pressure compensation, to ensure that the terminal injection pressure is stable at 0.6 ~ 1.0MPa. A porous plate airflow deflection device (aperture 0.8 ~ 1.2mm) is installed at the end of the pipeline to optimize the uniformity of nitrogen distribution. The installation was completed from May 24 to August 7.

[0040] Step 3: Replacement of the Spin Nitrogen Vortex Spray Gun

[0041] The original 18 external steam spray guns were replaced with self-spinning nitrogen vortex spray guns. Each spray gun has an integrated spiral flow channel (pitch gradually changes from 5mm to 2mm) and a trace water mist premixing chamber. The spray gun forms a high-speed rotating composite spray with deionized water (ratio 5% to 10%, pulse injection) through the nitrogen vortex effect, and the nozzle working pressure is controlled at 0.60.8MPa. The replacement work was completed on June 15, inhibiting scale adhesion and improving stripping efficiency.

[0042] Step 4: Scaling feedback control operation

[0043] The spray system was operated, and three ultrasonic scaling thickness sensors were installed on the inner wall of each converter evaporative cooler to detect scaling status once an hour. After the commissioning was completed on August 7, the initial nitrogen flow rate was set at 4000-5000m 3 / h, when the scaling thickness is greater than 20mm, the pulse frequency is automatically adjusted to 1015Hz, and the rotation speed of the vortex spray gun is increased by 10% to ensure that the scaling speed is ≤80mm / 6 months. On August 8, safe air delivery was achieved and steam consumption was reduced to zero.

[0044] Running parameters and results

[0045] Nitrogen source: surplus nitrogen from oxygen generator;

[0046] Pulse voltage reduction: 0.8-1.2MPa, frequency 5-10Hz (10-15Hz at high load);

[0047] Special pipe transportation: terminal pressure 0.6~1.0MPa, flow rate 4000~5000m 3 / h, consumption 10~12m 3 / t;

[0048] Vortex spray gun: nozzle pressure 0.6-0.8MPa, deionized water 5%-10%;

[0049] Feedback control: frequency adjustment when thickness > 20mm;

[0050] Results: Scaling rate ≤80mm / 6 months (actual thickness measured in 2 months <25mm), spray gun life ≥1.5 years, coarse ash proportion 25%~30%, steam consumption reduced from 20kg / t to zero, annual steam cost saving of approximately RMB 13.5 million (based on an annual output of 7.5 million tons). Specific embodiment 2

[0052] Implementation Background

[0053] A single converter in a steel mill (with an annual output of 2.5 million tons of steel) was used as a pilot. Before the transformation, the scaling rate of the evaporative cooler was 320 mm / month, the steam consumption was 20 kg / t, the spray gun life was 4 months, and the coarse ash accounted for 22%, affecting production efficiency and environmental compliance. Based on the experience of Example 1, the separate optimization of the method of the present invention was started on August 15, 2024, combined with the technical means of the claims, with the goal of reducing the scaling rate to ≤75 mm / 6 months and improving the dust removal efficiency.

[0054] Implementation steps

[0055] Step 1: Stepped pulse voltage reduction

[0056] The surplus high-purity nitrogen of the converter corresponding to the oxygen production unit was used to install a graded pulse pressure reduction device (two-stage pressure reducing valve + pulse generator). Construction began on August 15, reducing the high-pressure nitrogen (about 2.0MPa) to 0.9-1.2MPa, and the pulse frequency was set at 6-10Hz to form a dynamic medium-pressure nitrogen flow, which enhanced the scaling particle stripping effect and was better than the stability requirements of traditional pressure reduction.

[0057] Step 2: Adaptive pressure compensation dedicated pipe delivery

[0058] A dedicated pipe for a single converter (about 0.8 km in length) is connected from the dedicated pipeline of the oxygen production system, and an adaptive pressure compensation system is configured with a built-in pressure self-sensing module and an intelligent pressure compensation valve. 3 / h), adjust the pressure in real time, and keep the terminal injection pressure at 0.7-1.0MPa. Install the air flow deflection device (porous plate, pore size 0.8-1.2mm) at the end to ensure that the nitrogen evenly covers the cylinder wall and banana bend. The installation was completed on August 20.

[0059] Step 3: Replacement of the Spin Nitrogen Vortex Spray Gun

[0060] The 18 steam spray guns of a single converter were replaced with self-spinning nitrogen vortex spray guns, which contain spiral flow channels (pitch 5mm to 2mm gradient) and trace water mist premixing chambers. Nitrogen vortex and deionized water (ratio 6% to 10%, timed pulse injection) form a rotating composite spray with a nozzle pressure of 0.60.8MPa. The replacement was completed on August 25, and the effect of stripping and inhibiting scaling was significant.

[0061] Step 4: Scaling feedback control operation

[0062] The spray system was put into operation and three ultrasonic scaling thickness sensors were installed to monitor the scaling thickness every hour. The commissioning was completed on September 1st, with an initial flow rate of 4500-5000m 3 / h, when the thickness is greater than 20mm, the pulse frequency is increased to 12-15Hz, and the vortex spray gun speed is increased by 15% to ensure that the scaling rate is ≤75mm / 6 months. It was officially put into operation on September 5, and the steam consumption was reduced to zero.

[0063] Running parameters and results

[0064] Nitrogen source: surplus nitrogen from oxygen generator;

[0065] Pulse voltage reduction: 0.9-1.2MPa, frequency 6-10Hz (12-15Hz at high load);

[0066] Special pipe transportation: terminal pressure 0.7~1.0MPa, flow rate 4500~5000m 3 / h, consumption 11~12m 3 / t;

[0067] Vortex spray gun: nozzle pressure 0.6-0.8MPa, deionized water 6%-10%;

[0068] Feedback control: frequency adjustment when thickness > 20mm;

[0069] Results: Scaling rate ≤75mm / 6 months (actual thickness measured in 2 months <22mm), spray gun life ≥1.6 years, coarse ash proportion 26%~30%, steam consumption reduced from 20kg / t to zero, annual steam cost saving of about 4.5 million yuan (based on 2.5 million tons of output).

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for solving scaling in a steelmaking dry dust removal system, characterized in that: The steps include: Step 1: Utilize the surplus high-purity nitrogen from the oxygen generator of the steel plant, and use the graded pulse decompression technology to decompress the high-pressure nitrogen in stages to 0.8-1.2 MPa, forming a dynamic medium-pressure nitrogen flow with periodic pressure fluctuations to enhance the disturbance and stripping effect of the airflow on the scaling particles; Step 2: Adopt an adaptive pressure compensation dedicated pipe delivery system to deliver the dynamic medium-pressure nitrogen flow to the steel plant dry dust removal evaporative cooler spray system. The dedicated pipe system has a built-in pressure self-sensing module to compensate the pressure in real time according to the pipeline length and flue gas load, ensuring that the terminal injection pressure is stable at 0.6-1.0MPa, and optimizing the uniformity of nitrogen distribution through the airflow deflection device; Step 3: Replace the traditional steam spray gun with a self-spinning nitrogen vortex spray gun. The internal part of the spray gun integrates a spiral guide channel and a trace water mist premixing chamber. The nitrogen vortex effect is used to form a high-speed rotating composite spray with a trace amount of deionized water. The nozzle working pressure is controlled at 0.6-0.8MPa to peel off and inhibit scale adhesion. Step 4: Run the spray system, use the scaling feedback control technology combined with the ultrasonic scaling thickness sensor installed on the inner wall of the evaporative cooler to monitor the scaling status in real time and adjust the nitrogen pulse frequency and vortex spray gun speed in a linked manner.

2. The method according to claim 1, characterized in that: The graded pulse pressure reduction technology is realized through a multi-stage pressure reducing valve and a pulse generator. The nitrogen pressure fluctuation frequency is controlled at 5 to 10 Hz to enhance the impact stripping effect on scaling particles in the evaporative cooler.

3. The method according to claim 1, characterized in that The adaptive pressure compensation dedicated pipe delivery system includes at least one intelligent pressure compensation valve, which automatically adjusts the nitrogen pressure based on the flue gas temperature and flow changes, with a compensation range of 0.1 to 0.3 MPa.

4. The method according to claim 1, characterized in that The spiral guide channel of the self-spinning nitrogen vortex spray gun has a gradual pitch structure, with the pitch gradually changing from 5mm at the inlet end to 2mm at the outlet end to form an accelerating vortex and improve the spray stripping efficiency.

5. The method according to claim 1, characterized in that The trace water mist premixing chamber sprays deionized water through timed pulses. The water mist spraying frequency is synchronized with the nitrogen pulse frequency to keep the water content in the composite spray stable at 5% to 10%.

6. The method according to claim 1, characterized in that The scaling feedback control technology detects the scaling thickness once an hour through an ultrasonic sensor. When the thickness exceeds 20mm, the nitrogen pulse frequency is automatically increased to 10-15Hz to enhance the stripping ability.

7. The method according to claim 1, characterized in that The air flow deflection device adopts a porous plate structure with a pore size distribution of 0.8 to 1.2 mm, ensuring that the nitrogen spray covers the entire area of ​​the evaporative cooler cylinder wall and the banana bend.

8. The method according to claim 1, characterized in that: Trace amounts of deionized water account for 5% to 10% of the total spray volume.