Evaporative cold water scale cleaning method

Nowadays, many businesses or shops in life use evaporative condensers. Such a substrate is mainly used for refrigerating and cooling many foods, which is conducive to preserving freshness. However, everyone should know that this kind of equipment also needs to be cleaned after long-term use. If it is not cleaned and scale is allowed to form for a long time, it will cause blockage and lead to poor effect. So what are the methods for cleaning evaporative cold scale?

Cleaning of evaporative condenser (evaporative cooling) 1. Problems caused by the evaporative condenser water system Cooling water is continuously circulated in the circulation system. Due to the increase in water temperature, changes in water flow rate and water evaporation, various inorganic ions and organic substances

Cleaning of evaporative condenser (evaporative cooling)

1. Problems caused by evaporative condenser water system

Cooling water is continuously circulated in the circulation system. Due to the increase in water temperature, changes in water flow rate and water evaporation, the concentration of various inorganic ions and organic substances, the cooling tower and cold water pool are exposed to sunlight, wind and rain outdoors, the entry of dust and debris, and the combined effect of various factors such as equipment structure and materials, more serious sediment adhesion, equipment corrosion and massive growth of microorganisms will occur than in the DC system, as well as the resulting sludge and dirt clogging the pipes. These problems will threaten and destroy the factory's periodic safe production and even cause economic losses. Specifically, there are the following problems with cooling circulating water:

1. The formation of scale. It is mainly caused by two factors. On the one hand, after aeration in the cooling tower, CO2 in the water floats out of the water with the air, converting the highly soluble Ca(HCO3)2 in the water into CaCO3 with a very low concentration, which then precipitates and adheres to the metal surface to form scale. On the other hand, due to the evaporation and concentration of the circulating water, the Ca2+ ions and Mg2+ ions in the water reach a saturated state and precipitate to form scale.

CaCO3 is deposited on the heat transfer surface of the condenser to form dense calcium carbonate scale, which has poor thermal conductivity. Different scales have different thermal conductivity coefficients, but generally do not exceed 1.16 W/(m2·k), while the thermal conductivity coefficient of steel is 45 W/(m2·k). It can be seen that scale formation will inevitably affect the heat transfer efficiency of the condenser.

2. Oxygen corrosion. Since the circulating water is an open system, the water is rich in dissolved oxygen, which is very prone to oxygen corrosion. At the same time, during the concentration process of circulating cooling water, the concentrations of Cl- and SO42- in the water will increase. Cl- and SO42- will reduce the protective performance of the protective film on the metal, accelerate the anode reaction, accelerate corrosion, and cause a large number of rust nodules in the system. In severe cases, it will cause corrosion and perforation of equipment and pipelines, leading to premature scrapping.

3. Microbiological corrosion. The growth of microorganisms can also cause metal corrosion. This is because the mucus discharged by microorganisms and the deposits formed by inorganic scale and mud and sand debris adhere to the metal surface, forming an oxygen concentration cell, which promotes metal corrosion. In addition, there is a lack of oxygen between the metal surface and the sediment, so some anaerobic bacteria (mainly sulfate-reducing bacteria) are able to multiply, and the multiplication is faster when the temperature is around 30°C. It decomposes sulfate in water to produce H2S, which causes corrosion of carbon steel. The reaction is as follows:

SO24+8H+8e=S2+4H2O+energy (necessary for bacterial survival)Fe2++S2-=FeS↓

Iron bacteria are the main cause of steel rust. They can oxidize Fe2 into Fe3, and the energy released is needed for bacterial survival. Fe2+====== Fe2++Energy (necessary for bacteria to survive)

The corrosion of carbon steel caused by the above factors often causes the condenser tube wall to be corroded and perforated, resulting in leakage, or the process medium leaks into cooling water, polluting the water body, or cooling water seeps into the process medium, affecting the product.

4. Dust. Cooling towers achieve the purpose of cooling by forcing convection between water and air. It is equivalent to water washing the air, causing scale to be deposited when entering the system.

Regarding the evaporative cooling machine's fruit cleaning method, we must pay attention to the coordinated approach. It must be done manually. Improper cleaning methods can easily damage the machine, and it is easy for water to enter the machine's pipes or wires, which will have adverse consequences. The evaporative cooling machine must be cleaned of dust and scale from time to time, and it must be wiped continuously.