Liquor Cycle Chloride Control Restores Recovery Boiler Availability, 2000 Engineering Conference Proceedings

Larry A. Hiner, Michael A. Blair, Scott C. Moyer, and Dan Wiggins--Kraft recovery boilers operating today are experiencing higher fouling rates due to increased chloride content within the liquor cycle. It has been shown that excessive chloride content in recovery boiler ash results in increased fouling rates on the boiler’s convective surfaces (1, 2). Tighter liquor cycles and more efficient precipitator ash collection have resulted in higher chloride content in the liquor being sent to recovery boilers. By purging a small portion of the precipitator ash, the Alabama River Pulp and Alabama Pine Pulp Companies of Claiborne, Alabama have taken dramatic steps to restore the availability of their recovery boilers to design levels.

Their liquor chloride control strategy has allowed both boilers to run between planned outages without unscheduled cleanings or loss of steam temperature. The following examination of this strategy will describe operation at the mills before and after changes were made in the liquor cycles, and will compare the impacts of ash dumping to operational cost savings.