Reducing CRU Downtime - A Circulation and Water Chemistry Perspective, 2001 Engineering / Finishing & Converting Conference Proceedings

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This paper will review the concepts of boiler circulation as it applies to the chemical recovery unit (CRU) and will relate boiler water chemistry considerations to these concepts. A brief outline of the boiler water circulation system and the principles of circulation will be described. The focus of the discussion will be on the typical two-drum CRU design which was utilized from the mid-1960s to the mid-1980s. The paper examines the concerns with upgrading these boilers relative to firing system changes and capacity increases.

This paper will also present boiler water chemistry considerations from a manufacturer’s perspective as they apply to CRU’s. General boiler water quality principles are discussed and the most common failure mechanisms are outlined. The discussion focuses on the concepts of CRU corrosion and one manufacturer’s general recommendations for overall boiler water treatment principles which will provide the most trouble free operation in the long term.