Chemical scrubbing method for boiler

Abstract

The invention relates to a method of cleaning a boiler, in particular to a method of chemically cleaning a boiler, which comprises the following steps: caustic cleaning, acid cleaning, rinsing, passivating and liquid waste processing. The invention has the advantages that: 1. raw material adopted in the whole cleaning process has little toxic side effect and is environment-friendly. 2. Technological mistaken ideas on cleaning various prior boilers are overcome. 3. Sequential processing is easy according to cleaning solutions.

Description

technical field [0001] The invention relates to a boiler cleaning method, in particular to a boiler chemical cleaning method. Background technique [0002] With the construction of large-capacity thermal power units and the complexity of equipment materials, the requirements for the chemical cleaning process of boilers are also getting higher and higher. Chemical cleaning of the boiler is a necessary measure to clean the inner surface of the heating surface of the boiler and prevent accidents caused by corrosion and scaling on the heating surface. It is also one of the effective measures to improve the thermal efficiency of the boiler and the water vapor quality of the unit. At present, the chemical cleaning processes for boilers generally include: hydrochloric acid method, EDTA method, and citric acid method. [0003] Traditional hydrochloric acid cleaning is limited by the material of the cleaning equipment, so it cannot be used for cleaning equipment made of austenitic s...

AI Technical Summary

Problems solved by technology

[0005] The citric acid cleaning process generally does not cause harm to steel, and can be applied to various common boiler steels. However, the current cleaning process requires that the temperature of citric acid cleaning must be between 75-90 ° C, and the price of citric acid is relatively expensive. , the waste liquid is difficult to deal with, and generally needs to be sprayed to the coal yard and then sent to the boiler for incineration, and in the citric acid cleaning, when the concentration of iron ions in the cleaning liquid is too high and the pH value is greater than 4, the precipitation of ferric citrate may be formed. Affect the cleaning effect, and at the same time, after rinsing with citric acid according to the boiler cleaning regulations, hydrogen peroxide must not be used for passivation

[0006] The sodium nitrite passivation method commonly used in recent years has a very mature passivation process, but the waste liquid is relatively polluting to the environment, and it needs to be treated with sodium nitrite treatment agent for a period of time before it can be discharged up to the standard, and the cost of the treatment agent is relatively high. Be careful when disposing of waste liquid, there is a certain risk of operation