Reverse Superheater Fouling in the Al-PAC Recovery Boiler, 2000 Engineering Conference Proceedings

Larry Greenwood, Trevor Ip, Janice Dhak, Gary Kennard, Ibrahim Karidio, Mike Towers, Vic Uloth, Klaus Weiss--Al-Pac Forest Industries Inc. had the largest single drum recovery boiler in the world when it was completed in 1993. During the first four years after the mill startup in September 1993, the boiler experienced frequent pluggage problems. These initial problems were related to insufficient sootblowing, and were resolved by adding 12 sootblowers and modifying the sootblowing sequence and frequency. The problems that occurred later were related to chloride buildup as well as operational issues. While trying to resolve these issues, the mill personnel discovered a relationship between the SO2 emission rate and boiler pluggage. The mill also found that optimizing the liquor chemistry, firing parameters and combustion air system could reverse the boiler fouling process. The recovery boiler would no longer need to be shut down for a water wash except during the scheduled mill outage. The project incurred minimal expenditure and the benefit to the mill was estimated to be 2 million dollars per year.