This paper discusses the reasons for chemically cleaning a boiler at both the pre-operation (pre-commission) stage and the post-operation (post-commission) stage. The internal surfaces of a steam boiler can be chemically cleaned to remove contaminants which effect the efficiency of heat transfer and may ultimately result in failure of the plant. Contaminants may be present inside the boiler as a result of the manufacturing and installation of the boiler, process contamination, poor quality feedwater, poor maintenance or ineffective water treatment. The most common type of pre-operation cleaning conducted in Australia is a two-stage process involving alkaline detergent cleaning to remove oil and grease, and ammoniated citric acid cleaning to remove mill scale and corrosion products. The most common type of post-operation cleaning conducted in Australia is hydrochloric acid cleaning.
Keywords: chemical cleaning, boiler, pre-commission, pre-operation, post-commission, postoperation, scale, deposit, corrosion