In the process of circulating cooling water treatment, the most commonly used is scale inhibitor, 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 pipeline and equipment, and corrosion will shorten the service life of the equipment, increase maintenance costs, and even cause accidents and affect production. In general, special agents shall be selected for different circulating water systems according to the operation requirements of the system. For general large-scale industrial circulating water systems, chemicals with the functions of scale inhibition, corrosion inhibition and decentralized recheck are mainly added. In addition, certain bactericidal and algal killing agents are regularly added according to the operation of the system and the growth of bacteria and algae.