scope:

This Technical Information Paper is designed to answer the question, "How do we avoid having failures in chemical cleaning of boilers?" It covers key points in assuring successful boiler chemical cleaning projects, but is not intended to be an exhaustive treatment of the subject of chemical cleaning. It is an overview, with references for those interested in pursuing the subject further.

This TIP does not address how the decision is made as to when chemical cleaning is necessary. That is a major topic that would require a paper of its own, larger than this one, for adequate treatment.

Keys to successful chemical cleaning projects can be divided into four major topics:

• Solvent selection

• Engineering and execution of the project

• Post acid cleaning inspection and flushing

• Start-up/passivation

Once a solvent is selected, boiler preparations must be made in order to accommodate:

• Safety

• Temporary piping for filling and, draining and venting the boiler.

• Boiler venting, filling and draining.

• Permanent instrument protection.

• Solvent agitation and uniform distribution within the boiler.

• Protection of the superheater and sweetwater condenser.

• Solvent heating.

• Solvent sampling.

• Monitoring of solvent level in the steam drum.

• Solvent disposal

• Inspection and flushing

- Scaffolding

- Hoses

- Special tools, videoprobe, digital camera, etc.

- Manpower needs

• Start-up/passivation