PROCESS FOR LOW TEMPERATURE CHEMICAL CLEANING AND PASSIVATION IN BOILER OF THERMAL POWER PLANT WITH EDTA

摘要

The present invention relates to a process for the chemical cleaning of a boiler of a thermal power plant, and in particular relates to a process for low temperature chemical cleaning and passivation with EDTA. The process comprises the following steps: A. connecting a chemical cleaning station with a system to be cleaned so as to form a cleaning system; after the completion of a hydraulic test on the connected cleaning system, turning on recycled water and cleaning until the water is transparent and free of impurities; B. raising the temperature of the cleaning system in cycles; C. washing with alkali and rinsing; and D. washing with EDTA; passivation. The present invention has the following features: 1. it saves energy and consumption, and reduces the cleaning period and costs; and 2. the cleaning and passivation of the boiler can be achieved in one step. A passivation process is added after the low temperature cleaning with EDTA. The passivation of the cleaned boiler is achieved by adjusting the pH value of the EDTA cleaning solution via addition of NaOH into the EDTA cleaning solution. The cleaning process of the present invention is suitable for boilers of various specifications, and facilitates implementation both on-site and on a widespread basis.