There are several ways to clean the cooling tower circulating water system. The common ones are physical cleaning of the cooling tower circulating water system and chemical cleaning of the cooling tower circulating water system. If the fouling exceeds 3mm, it is recommended to use the cooling tower circulating water system for chemical cleaning, or even to carry out physical blasting treatment after chemical cleaning.
1. Physical cleaning of cooling tower circulating water system:
The physical cleaning of cooling towers circulating water system mainly uses the scouring effect of water flow or the brushing, wiping and scraping functions of appliances to remove sediments in equipment and pipelines. The main methods of physical cleaning are: high pressure water cleaning and appliance cleaning.
① High-pressure water cleaning: High-pressure water cleaning is a method of cleaning the surface to be cleaned by using a powerful jet of high-speed water to act on the surface to be cleaned at a certain angle. It is usually used to clean the inside and outside the tube bundle of the heat exchanger and the cleaning of the cooling tower packing, but the effect is limited.
② Apparatus cleaning: The method of cleaning the system pipeline with cleaning tools such as brushes or gunners. Usually used for cleaning inside heat exchanger tubes.
2. Chemical cleaning of cooling tower circulating water system:
The chemical cleaning method is a cleaning method that dissolves, loosens, falls off or peels off the deposits in the cleaned equipment and pipelines through the chemical action of chemicals. Generally speaking, the method of chemical cleaning can not only remove the dirt in the system, but also remove various scales, metal corrosion and biological slime. The chemical cleaning method is suitable for vertical and horizontal shell and tube condensers.
1. Connect the water pump: connect the water pipe to the circulating water pump, pay attention to the direction of the water inlet and outlet of the water pump, and ensure that the direction of the circulating water in the shell tube is ‘bottom in and top out’. The water pump connection pipe interface can be selected at the position of the pressure gauge, thermometer, sewage pipe, etc., or it can be opened by itself.
2. Slime stripping: calculate the amount of circulating water, calculate the dosing amount according to the amount of circulating water, add the slime stripping agent according to the ratio of 600~800g per ton of water (take SGR0117 as an example), turn on the water pump to circulate for 4 hours, and the cycle process Clean up the stripped suspended matter in time.
3. Descaling: Detect the PH value of the circulating water before adding the descaling agent (SGR0119), which is used to compare the change of the ph value before and after cleaning; according to the amount of circulating water, add the descaling agent at a ratio of 1:10 to 1:20 to prevent descaling If the reaction speed of the detergent is too fast to block the system, you can add the descaling agent in 3~4 times at intervals of 20 minutes; cycle for 4~8 hours, pay attention to the pH value of the circulating cleaning solution during the cycle, if the detected pH reaches about 4~5, add it again It turns red after a small amount of descaler, indicating that it is clean.
4. Rinse: After the main wash and descaling, wash the shell tube repeatedly with clean water until it is nearly neutral (ph=6.5±0.5) and the circulating water is clear.
5. Pre-film passivation (also after starting up): Before pre-filming, ensure that the water system is cleaned, add pre-filming agent SGR0120 according to the amount of circulating water, add pre-filming agent SGR0120 1L according to 1 ton of water, and put it in several times. During the dosing process, the ph needs to be detected, and the PH value should be controlled at 6.5±0.5 through the dosing amount.
6. Cleaning and acceptance: After cleaning, start the machine and run it for two hours with the load of the unit above 80%, check the temperature difference between the corresponding shell and tube ends. If the temperature difference between the ends is not higher than 2°C, it indicates that the cleaning effect is good.
