1、 Overview

Recirculating cooling water system refers to a water supply system that exchanges heat and cools the cooling water, and is used for recycling. It includes two types: open and closed.

2、 Principle of circulating cooling water system

A cooling water system that uses water as a cooling medium and circulates it. It mainly consists of cooling equipment, water pumps, and pipelines. After the cold water flows through the production equipment that needs to be cooled (often referred to as heat exchange equipment, such as heat exchangers, condensers, and reactors), the temperature rises. If it is discharged immediately, the cold water is only used once (called a direct flow cooling water system). If the heated cold water flows through the cooling equipment, the water temperature will drop back. It can be pumped back to the production equipment for reuse, greatly reducing the amount of cold water used and often saving more than 95%. Cooling water accounts for about 70% of industrial water consumption, therefore, the circulating cooling water system plays a role in saving a large amount of industrial water.

3、 Classification of circulating cooling water systems

1. Open type

There are two types of cooling equipment: cooling pools and cooling towers, both of which mainly rely on water evaporation to reduce water temperature. Furthermore, cooling towers often use fans to promote evaporation, and cooling water is often blown away. Therefore, the open circulating cooling water system must be supplied with fresh water. Due to evaporation and concentration of circulating water, the concentration process will promote salt scaling (see sediment control). Supplemental water has a dilution effect, and its flow rate is often determined based on the concentration limit of circulating water. Usually, the amount of supplementary water exceeds the amount of water lost through evaporation and wind blowing, so it is necessary to discharge some circulating water (called wastewater) to maintain the balance of water volume.

2. Closed type

The closed circulating cooling water system adopts closed cooling equipment, and the circulating water flows in the pipes, while air is usually used to dissipate heat outside the pipes. Apart from material leakage from the heat exchange equipment, there are no other factors that alter the quality of the circulating water. In order to prevent the formation of salt deposits in heat exchange equipment, sometimes the cooling water needs to be softened (see water softening). To prevent corrosion of heat exchange equipment, corrosion inhibitors are often added; Attention should be paid to safety when using high concentration and highly toxic corrosion inhibitors, and the cooling water discharged during maintenance should be properly disposed of

4、 Construction characteristics

When the flow rate of the medium in the monitoring system pipeline is too low or too high due to blockage or other factors, the offline alarm point (when the flow rate is too low) or online alarm point (when the flow rate is too high) can be promptly sent to the control system to provide switch signals. We call it a traffic alarm switch.