Pre-film solution for circulating water system

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5.1 Preparation work. 1. The chemical cleaning of circulating water is completed and the pool is cleaned. .2. Quickly fill the pool with water and drain the sewage at the same time. Drain the water while draining the water until the pool water becomes clear water. Establish and maintain the pool at a high liquid level. .3. The analysis and monitoring work is ready, and various chemicals are prepared. .4. The pre-film monitoring coupons have been hung. 2 This step of pre-filming operation is to add pre-film agent H-11 and high-efficiency dispersing scale inhibitor H-51 into the pool. It can form a protective film on the clean metal surface, so that the cooling equipment can reduce or slow down corrosion as much as possible during the production process. Therefore, it is required to passivate the metal surface immediately after passing the chemical cleaning and when the metal surface is completely clean. .1. Contact the duty dispatcher to inform each workshop squad leader to turn off the methanol and air separation equipment cold exchange equipment discharge valves, open the exhaust valve, fill the circulating pool with water at the maximum flow rate and discharge sewage at the same time, discharge while water is flowing in, until the water in the pool becomes clear water, and establish and maintain a high liquid level in the pool. .2. When the pool reaches a high liquid level, start each circulating water pump according to normal driving procedures to circulate water. .3. Check whether the water distribution in the water distribution system is uniform and whether the circulating water pumps are operating normally; when the heat exchangers of the methanol and air separation units are filled with water, the relevant positions should immediately close the exhaust valves. 4. Use H2SO4 (sulfuric acid) to adjust the PH value to 6.0-7.0 .5. Add pre-filming agent H-11 to the pool according to the specified amount and add high-efficiency dispersing scale inhibitor H-51 twice. Continuously add 1.5kg/h of H-11 pre-filming agent to the pool to control the concentration of the agent at [300-350mg/L and total control at ≥80mg/L]. Within a certain value, the pre-filming time is generally 48 hours at room temperature. If the water temperature is high, the pre-filming time can be shortened appropriately. 6. After confirming that the pre-film is qualified, open the supplementary water and pool drain valves, reduce the concentration of chemicals in the circulating water as soon as possible, and put the dosing machine into operation. Use cl2 for sterilization and control the residual recording to 0.3-1mgL. 7. Then switch to normal operation or cold operation according to the process start-up speed. If the cold operation should be adjusted according to the cold control index. The water quality control index for cold operation is PH ≥ 8. 5 Content PO43- (phosphate), solubility is about 10mg/L