Replacement qualification criteria

In the inspection, maintenance, and repair of chlorine-based systems and chlorine water systems, the standard for successful displacement is that the purity, concentration, and stability of the substances after displacement meet certain specified requirements. The specific standards are determined according to **relevant standards and manufacturer requirements. For chlorine systems, it is generally required that the purity of chlorine after displacement be no less than 99.5%, with no impurities or unusual odors. At the same time, it is also necessary to ensure that parameters such as the pressure and flow rate of chlorine meet the requirements. In addition, there are also corresponding standards for the amount of chlorine gas leakage during the displacement process. For chlorine water systems, the standards for acceptable water replacement are quite strict, and these mainly include the following aspects: 1. Completely remove existing impurities such as chlorides and chlorates, to ensure that the chloride content in the newly replaced water does not exceed the specified limits ； 2. The concentration of chlorine water meets the specified requirements, typically around 50 mg/L ； 3. Parameters of the system such as pH value and temperature are within the specified ranges ； 4. The water used for replacement must undergo strict disinfection to ensure it is free from bacteria, viruses, and other contaminants. It should be noted that the qualified standards for chlorine water replacement may vary among different manufacturers and in different applications; the specific requirements need to be determined based on actual needs. .

Thank you. Are there any national or industry standards regarding chlorine water displacement?

Yes, there are relevant **standards and industry standards** for chlorine water displacement. **The standard is GB/T 14797-2017 \"Quality specifications for chlorine water for industrial use\", which specifies the name and classification of chlorine water for industrial use, requirements, testing methods, inspection rules, as well as requirements regarding labeling, packaging, transportation, and storage. These include requirements for various parameters such as chloride content, pH value, turbidity, color intensity, fluoride content, nitrite content, heavy metal content, and microbial contamination. In addition, there are industry standards as well; for example, standards such as the Operating Procedures for Hygiene Management of Water Treatment Agents and Water Treatment Equipment (CJ/T221-2005) also contain regulations regarding chlorine water replacement. In addition, some chlorine water manufacturers also carry out quality control and testing according to their own needs and standards. It should be noted that requirements and standards for chlorine water may vary across different regions and industries; the specific options need to be determined based on actual needs. .

Okay, thank you. What I would like to ask is: how much chlorine water needs to be replaced during maintenance work in order to carry out the repairs, and are there any specific guidelines for this?

The amount of chlorine water required for displacement must be determined based on the specific maintenance requirements; different systems and equipment have varying demands for displacement. During chlor-alkali plant maintenance, it is usually necessary to clean and replace the chlorine water system in order to eliminate old, stale, or expired chlorine water. Generally, before replacing the chlorine water, it is necessary to first test it to determine whether its chloride ion content and pH value meet the standard requirements, and then proceed with the replacement based on those results. According to the **standard GB/T 14797-2017 \"Quality specifications for industrial chlorine water\", the chloride ion content in chlorine water should be below 40 mg/L, with a pH value ranging from 6.5 to 8.5. During replacement, it is usually necessary to completely drain the old chlorine water before adding fresh chlorine water. To ensure the quality of chlorine water, a chemical cleaning is generally carried out before adding new chlorine water, in order to remove old dirt and residues from the pipelines and equipment. During this process, it is important to ensure that parameters such as the concentration of the cleaning agent, the duration of use, and the temperature meet the required standards in order to achieve an effective cleaning result. In short, the amount of chlorine water required for displacement must be determined based on actual conditions, and it must meet the requirements of **standards and relevant regulations. When performing maintenance on chlor-alkali plants, it is recommended to follow the manufacturer’s requirements and the actual conditions. .