In the process of circulating cooling water treatment, scale inhibitors are most commonly used, because circulating water will produce scale and dirt during operation, and will also directly or indirectly corrode metal equipment and pipes. A large amount of scale precipitation will reduce the heat exchange effect of the heat exchanger, block the pipes and equipment, and corrosion will shorten the service life of the equipment, increase the maintenance cost, and even cause accidents and affect production. Generally speaking, for different circulating water systems, special reagents should be screened according to the operating requirements of the system. In general, large-scale industrial circulating water systems mainly add agents with scale inhibition, corrosion inhibition and decentralized review functions. In addition, some bactericides and algicides will be added regularly according to the operation of the system and the reproduction of bacteria and algae.