Recycling Water Treatment Technology

During the operation of industrial circulating cooling water system, the circulating water is continuously concentrated due to water evaporation and wind loss. The excessive salt content, the increase of anions and cations, and the obvious change of pH value result in the deterioration of water quality. The temperature, PH value and nutrient composition of circulating water are conducive to the reproduction of microorganisms. Sufficient sunlight on the cooling tower is an ideal place for algae growth. 。 The scaling control and corrosion control, microbial control and so on, the need for recycling water treatment is inevitable.

The main problems in the operation of circulating water are as follows:

(1) Scale: As the circulating water evaporates continuously during the cooling process, the concentration of salt in the water increases continuously, which is more than the solubility of some salts and precipitates. Common scales are calcium carbonate, calcium phosphate, magnesium silicate and so on. The scales have compact texture, which greatly reduces the heat transfer efficiency. The scales thickness of 0.6 mm reduces the heat transfer coefficient by 20%.

(2) Fouling: Fouling is mainly composed of organic matter, microbial colonies and secretions, sediment and dust in water. The soft texture of the fouling not only reduces the heat transfer efficiency, but also causes corrosion under the fouling and shortens the service life of the equipment.

(3) Corrosion: The corrosion of circulating water to heat exchanger equipment is mainly electrochemical corrosion. The causes are equipment manufacturing defects, sufficient oxygen in water, corrosive ions in water (Cl-, Fe2+, Cu2+) and fouling caused by mucus secreted by microorganisms. The consequences of corrosion are very serious, even if the heat exchanger and water pipeline equipment are scrapped without control for a very short time.

(4) Microbial slime: Because circulating water is dissolved with sufficient oxygen, suitable temperature and nutrient enrichment conditions, it is very suitable for the growth and propagation of microorganisms. If not controlled in time, it will quickly lead to deterioration of water quality, odor, blackening, a large number of fouling deposits in cooling towers or even blockage, cooling and heat dissipation effect will be greatly reduced, and equipment corrosion will be aggravated.

Therefore, the reproduction of microorganisms must be controlled in the treatment of circulating water.

Key points of circulating water treatment technology: According to the characteristics and technological conditions of enterprise circulating water system and local water quality characteristics, water treatment scheme suitable for enterprise operating conditions is selected, and circulating water index is controlled to operate within a certain range by adding drugs, which not only ensures the long-term operation of production equipment, but also improves the utilization rate of circulating water.

The utilization of circulating water treatment technology can not only bring remarkable economic benefits to enterprises, but also bring good social benefits to society. So the application of circulating water treatment technology is very necessary.