Coupling cleaning method for surface evaporation air cooler

Abstract

In order to solve the problems that in the daily operation process of a surface evaporation air cooler, scaling, corrosion, biological slime and the like often happen to a water circulation system, normal operation of the system is seriously affected, the operation cost is increased, meanwhile, the normal service life of equipment is shortened, and the equipment is possibly scrapped in advance, the surface evaporation air cooler coupling cleaning technology is invented. Through effective application of the technology, various water scales, microorganism slime and corrosion products in a water system are effectively and thoroughly removed, meanwhile, a layer of protective film is formed on the surface of a pipeline, and a metal pipe bundle is effectively protected. Safe and normal operation of the system is guaranteed, cooling efficiency is remarkably improved, corrosion hidden danger is eliminated, equipment operation efficiency is improved, and the service life of equipment is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and particularly relates to a surface evaporation air cooler coupling cleaning method. BACKGROUND

[0002] During daily operation of the surface evaporation air cooler, fouling, corrosion and biological slime often occur in the cooling water circulation system, which seriously affects the normal operation of the system, increases the operation cost of the system and shortens the normal service life of the equipment.

[0003] The cooling water of the surface evaporation air cooler contains a large amount of Ca2+, Mg2+ and other fouling ions, which are easily saturated and deposited on the pipeline and around the grid when the water temperature rises or evaporates and concentrates, so that the water scale is formed on the metal surface. At the same time, the silt and various bacteria and algae in the water enter the water system, and a large amount of microbial slime is produced in the system due to the suitable temperature for the growth and reproduction of the microorganisms, which is attached to the pipeline and mixed with the water scale to form biological fouling. When the fan on the surface evaporation air cooler works, a large amount of dust in the air is adsorbed, so that the grid is almost full of dust.

[0004] The fouling, microbial slime and the corrosion faults accompanied thereby have a great influence on the safety of the system, and the system needs to be cleaned regularly. The traditional cleaning method cannot achieve the expected effect due to the single action, and a new cleaning technology needs to be invented to meet the actual cleaning needs.

[0005] The purpose of the present application is to invent a surface evaporation air cooler coupling cleaning technology, which can completely remove various water scale, microbial slime and corrosion products in the cooling water system, ensure the safe and normal operation of the system, significantly improve the cooling efficiency, protect the metal tube bundle, eliminate the corrosion hidden danger and prolong the service life of the equipment. SUMMARY

[0006] The purpose of the present application is to invent a surface evaporation air cooler coupling cleaning technology, which can completely remove various water scale, microbial slime and corrosion products in the cooling water system, ensure the safe and normal operation of the system, significantly improve the cooling efficiency, protect the metal tube bundle, eliminate the corrosion hidden danger and prolong the service life of the equipment.

[0007] The purpose of the present application is achieved in the following way: a surface evaporation air cooler coupling cleaning method adopts physical cleaning + chemical cleaning coupling cleaning technology, physical cleaning: 12 filters are operated in parallel on site, first, the cooling water of the evaporation air cooler to be cleaned is short-circuited and separated from other evaporation air cooler systems for separate cleaning, first, the dirt on the surface of the evaporation air cooler is cleaned by a high-pressure cleaning water gun, the pressure of the high-pressure cleaning water gun is 20-70 MPa, at the same time, a vibration rod and a steel wire brush are used to remove stubborn dirt in dead corners, the vibration frequency of the vibration rod is 20-100 Hz, secondly, the sludge of the water tank of the evaporation air cooler is cleaned to ensure that the surface of the evaporation air cooler and the water tank are free of sludge; chemical cleaning: a cleaning circulation system is established, the cleaning circulation system comprises a spraying device, a hose, a corrosion-resistant pump, a water storage tank, a liquid preparation tank and a chemical feeding device, the chemicals are input into the liquid preparation tank through the chemical feeding device, the chemicals in the liquid preparation tank are pressurized by the corrosion-resistant pump and delivered to the water storage tank through the hose, the chemicals in the water storage tank are input into the spraying device by the corrosion-resistant pump, and the nozzles of the spraying device are arranged above the evaporation air cooler for spraying cleaning; a water outlet pipe is arranged below the cleaning tank, and a valve is arranged on the water outlet pipe.

[0008] The chemicals and the proportioning for chemical cleaning are as follows: cleaning penetrant: 0.15-0.3%, accelerator: 0.4%, defoaming agent: 0.2-0.6%, corrosion inhibitor: 0.3%, and scale removal cleaning agent: 6-8%.

[0009] The system operation pressure of chemical cleaning is controlled at 0.3-0.6 MPa.

[0010] The cleaning temperature of chemical cleaning is controlled at 35-50 DEG C.

[0011] The water flushing process is carried out until the end, and the end of the water flushing process is judged when the PH value of the outlet solution is equal to 4-4.5.

[0012] The waste liquid of chemical cleaning is neutralized and discharged after reaching the standard, and the end is judged when the PH value of the outlet solution is equal to 6-9.

[0013] The present application has the following beneficial effects: through the coupling cleaning technology, the surface evaporation air cooler is cleaned, various scales, microbial sludge and corrosion products in the water system are effectively and completely removed, the scale removal rate is greater than 85%, the corrosion rate is less than 3 g / m2.h, and at the same time of cleaning, a protective film is formed on the surface of the pipeline, which not only ensures the safe and normal operation of the system, effectively protects the metal tube bundle and eliminates the corrosion hidden danger, but also improves the equipment operation efficiency and prolongs the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0014] The present application will be further described below with reference to the drawings.

[0015] Figure 1It is the structural schematic view of the chemical cleaning system of the present application.

[0016] Among them: 1. spraying device, 2. liquid, 3. hose, 4. corrosion-resistant pump, 5. liquid tank, 6. dosing device. DETAILED DESCRIPTION

[0017] A "physical cleaning + chemical cleaning" coupling cleaning technology is adopted to completely remove various scales, microbial slime and corrosion products in the cooling water system, ensure safe and efficient operation of the system, significantly improve the cooling efficiency, the cleaning process does not cause any corrosion damage to the metal components of the equipment, does not cause system damage and leakage, can effectively prolong the service life of the surface evaporation air cooler, and can form a protective film with excellent corrosion resistance on the metal surface after cleaning, to ensure safe, reliable and efficient operation of the system after cleaning.

[0018] 1. Physical cleaning: generally, multiple filters are connected in parallel on site, in order to ensure normal operation of other evaporative air coolers, the cooling water of the evaporative air cooler to be cleaned is first short-circuited and separated from other evaporative air cooler systems, so as to facilitate individual cleaning. The high-pressure cleaning gun (pressure 31.5 MPa) is used to clean the dirt on the surface of the evaporative air cooler, to remove surface rust, suspended dust and slime, and at the same time, a vibration rod and other auxiliary tools are used to remove stubborn dirt in dead corners. Secondly, the sludge in the water tank of the evaporative air cooler needs to be cleaned to ensure that the surface of the evaporative air cooler and the water tank are free of sludge. The spraying device is a key component in the surface evaporative air cooler system, mainly used for strengthening heat exchange efficiency through water evaporation.

[0019] 2. Chemical cleaning: according to the plan view, the cleaning circuit is connected to establish a temporary cleaning circulation system, and one cooler is taken as one cleaning unit, which is composed of an acid-resistant pump, a liquid tank, acid-resistant hoses and the equipment to be cleaned to form a small self-circulating cleaning system, and the natural spraying mode is adopted for circulating cleaning and scale removal. The amount of reagent is as follows: main equipment: two acid-resistant pumps, one liquid tank, several acid-resistant hoses and two distribution panels.

[0020]

[0021] Technical points: 1. The system operating pressure should be controlled within the range of conventional safety pressure 0.3~0.6MPa. 2. Considering the characteristics of the cleaning agent, the cleaning temperature is required to be controlled between 35°C~50°C. 3. All cleaning agents are added at the dosing point of the system water tank. The type of the dosing device is BJF-JY. 4. After the cleaning agent is prepared and stirred uniformly in the cleaning tank, it is pumped into the system by a corrosion-resistant pump for natural spraying and circulating cleaning. 5. During the cleaning process, the pH of the system is monitored every hour, and the cleaning is qualified when the pH is less than 4. The end point of cleaning is determined by the pH value at the outlet of the system. The concentration of the acid tends to be stable and unchanged, and the difference (absolute value) between the results of two acid concentration analyses at a certain time interval is less than 0.2%. For carbonate scale, basically no CO2 bubbles are generated. 6. The cleaning time is estimated to be 2-4 hours. 7. After the cleaning reaches the end point, water flushing treatment is performed until the end. The end point of the water flushing process is determined when the pH value of the outlet solution is equal to 4~4.5. 8. The acid cleaning waste liquid is treated by neutralization and discharged after reaching the standard. The end point is determined when the pH value of the outlet solution is equal to 6~9. Example 1

[0022] The above technology is used in the cleaning of the surface evaporation air cooler in the cooling system of the new steelmaking production line of TISCO. The cleaning of the evaporation air cooler of the crystallizer of the regional carbon steel continuous casting, the 1# and 2# stainless steel continuous casting crystallizer, the indirect cooling water of the continuous casting, the cooling water system of smelting, and the cooling water system of the RH equipment are all carried out by using the coupling cleaning technology. Through the effective application of the technology, various scales, microbial sludge, and corrosion products in the cooling water system are effectively and completely removed, and at the same time, a protective film is formed on the surface of the pipeline, effectively protecting the metal pipe bundle. Not only is the safe and normal operation of the system ensured, but also the cooling efficiency is significantly improved, the corrosion hidden danger is eliminated, the equipment operation efficiency is improved, and the service life of the equipment is prolonged.

[0023] 1. First, check the spraying system and unblock if there is any blockage. At the same time, use steel brushes and vibration rods to remove stubborn dirt to prepare for the following cleaning.

[0024] 2. Clean the air cooling evaporator tank and remove the sludge in the tank. Use a high-pressure water gun to flush the scale and part of the biological sludge on the surface of the pipe.

[0025] 3. Control the water temperature between 35°C~50°C. Use the dosing device to add the cleaning agent. The concentration of the cleaning agent is determined according to the table in the specific embodiment. The amount of the cleaning agent is calculated according to the size and water volume of the system. The water volume of a single system is 1 ton. Start the circulating pump and perform circulating cleaning.

[0026] 4. Monitor the pH of the system every hour during the cleaning process. The cleaning time is three hours.

[0027] 5. When the acid concentration at the system outlet tends to be stable and unchanged, and the difference (absolute value) between two acid concentration analyses performed at a certain time interval is less than 0.2%, for carbonate scale, there is basically no CO2 bubble generation. When the pH value of the outlet solution is equal to 4 to 4.5, the rinsing can be stopped, and then a high-pressure water gun can be used to rinse away stubborn scale in dead corners.

[0028] 6. Pickling waste liquid shall be neutralized and discharged after meeting the standards (pH value equal to 6-9).

[0029] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for coupled cleaning of a surface evaporative air cooler, characterized in that: A combined physical and chemical cleaning technology is employed. For physical cleaning, 12 filters operate in parallel on-site. First, the cooling water of the evaporative air cooler requiring cleaning is short-circuited to separate it from other evaporative air cooler systems for individual cleaning. High-pressure cleaning water guns, with a pressure of 20-70 kcal / kg, are used to clean the surface dirt of the evaporative air cooler. MPa, combined with a vibrating rod and wire brush to remove stubborn dirt from hard-to-reach areas. The vibration frequency of the vibrating rod is 20-100Hz. Next, the sludge in the evaporative air cooler water tank is cleaned to ensure that the surface of the evaporative air cooler and the water tank are free of sludge. Chemical cleaning: A cleaning circulation system is established, which includes a spray device, hoses, a corrosion-resistant pump, a water storage tank, a solution tank, and a chemical dosing device. The chemical is introduced into the solution tank through the chemical dosing device. The chemical in the solution tank is pressurized by the corrosion-resistant pump and delivered to the water storage tank through the hose. The chemical in the water storage tank is introduced into the spray device through the corrosion-resistant pump. The spray nozzles of the spray device are set above the evaporative air cooler for spray cleaning. A water outlet pipe is set at the bottom of the cleaning tank, and a valve is installed on the water outlet pipe.

2. The surface evaporation air cooler coupled cleaning method according to claim 1, characterized in that: The chemical cleaning agents and their proportions are as follows: penetrant: 0.15~0.3%, accelerator: 0.4%, defoamer: 0.2~0.6%, corrosion inhibitor: 0.3%, and descaling agent: 6~8%.

3. The surface evaporation air cooler coupled cleaning method according to claim 1, characterized in that: The operating pressure of the chemical cleaning system is controlled at 0.3~0.6MPa.

4. The surface evaporation air cooler coupled cleaning method according to claim 1, characterized in that: The cleaning temperature for chemical cleaning should be controlled between 35℃ and 50℃.

5. The surface evaporation air cooler coupled cleaning method according to claim 1, characterized in that: Chemical cleaning is followed by water rinsing until the process ends. The endpoint of the water rinsing process is determined when the pH value of the outlet solution is equal to 4 to 4.

5.

6. The surface evaporation air cooler coupled cleaning method according to claim 1, characterized in that: Waste liquid from chemical cleaning is neutralized and discharged after meeting standards. The endpoint is determined by the pH value of the outlet solution being 6 to 9.

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