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This post was last edited by Industrial Cleaning 123 on 2016-4-8 at 09:22. Chemical cleaning of pipes, degreasing of pipes, acid cleaning of pipes – Process standards for chemical pipe cleaning: Xiangguang Cleaning. Objects and purposes of cleaning: Through chemical cleaning, rust and other impurities on pipelines, as well as on connecting elbows and flanges, are removed, thereby achieving a metal surface cleanliness that meets the requirements for production. 1. Degreasing: The purpose of degreasing cleaning is to remove oils such as rust preventive coatings from the pipelines, in order to ensure uniform pickling. 2. Water flushing: The purpose of the second water flushing step is to remove any residual degreasing solution remaining in the pipes, as well as to dislodge any remaining impurities from the surface so that they can be carried away. 3. Acid cleaning: The aim of acid cleaning is to utilize the chemical and electrochemical reactions between the acid solution and various types of dirt, thereby producing soluble substances that are then carried away through the pipes, thus achieving the goal of cleaning the metal surface. Pickling is a key step in the entire chemical cleaning process. 4. Water flushing and displacement: After the pickling process is complete, industrial water is used to displace the pickling solution and carry out flushing, with the aim of removing any remaining pickling solution as well as any solid particles that have been washed away. The process can be completed when the pH value of the effluent is close to neutral (pH 6–9) and all drain liquids have been discharged to the clarification tank. 5. Rinsing: Rinsing involves using a rinsing agent to complex with the iron ions remaining in the system, thereby removing any surface rust that may have formed on the metal surface during washing, reducing the concentration of iron ions in the system, and lowering the surface activity of the metal being cleaned – all of which lay the foundation for passivation. 6. Neutralization and passivation: The metal surface after pickling is in a highly active state, making it prone to the formation of secondary rust. By passivating the metal surface, an oxide layer can be formed on it, putting the metal in a passive state and preventing the formation of secondary rust. 7. Manual cleaning, inspection, and acceptance: After cleaning is completed, the system is cleaned by opening all drain valves along the pipelines to remove any remaining cleaning solution. Relevant personnel are then involved in the inspection and acceptance process, followed by the disassembly of the pipelines. 7. Waste liquid treatment: The materials used in this cleaning process, as well as the products resulting from the reactions, do not contain heavy metal ions or highly toxic substances; therefore, the waste liquids can be easily treated to meet regulatory standards. The specific handling methods are as follows: 1. The wastewater after water washing, containing no special pollutants, can be discharged at the sewage discharge point designated by Party A. 2. The cleaning waste liquids from each stage, once neutralized to a pH of 6-9, are discharged at the disposal site designated by Party A. 3. After preliminary treatment, the cleaning waste liquid is fed into Party A’s sewage treatment system located in the vicinity for centralized treatment, and is discharged only after it meets the required standards. 8. Cleaning Summary: After all chemical cleaning tasks are completed, organize the relevant data and original records, prepare a summary of the work, and submit a report to Party A.