Effects of chemical composition on the removability of recovery boiler fireside deposits

Effective removal of fireside deposits by sootblowers in a kraft recovery boiler is critically important for maintaining stable operation of the boiler. The removability of recovery boiler deposits was studied under simulated conditions in the laboratory using an entrained flow reactor (EFR) coupled with an air jet blow-off apparatus. Synthetic carryover particles were fed into the EFR controlled at 800 C. The resulting deposits, which collected on an air-cooled probe at the EFR exit, were removed with a high-pressure air jet. The results show that the required peak impact pressure (PIP) of the jet to remove a deposit increased markedly with an increase in the chloride content of the deposit, and, to a lesser extent, with an increase in potassium and carbonate content. The combined effect of these components was significantly greater than the sum of the effects of individual components. The results also show that deposits were more difficult to remove as the tube surface temperature increased.This work is part of the research program on “Improving Recovery Boiler Performance, Emission and Safety” jointly supported by ABB Alstom Power Inc., Ahlstrom Corporation, Aracruz Celulose S.A., Babcock & Wilcox Company, Boise Cascade Corporation, Bowater Canada Inc., Clyde-Bergemann Inc., Champion International Corporation, Daishowa-Marubeni International Ltd., Domtar Inc., Domtar-Eddy Specialty Papers Ltd., Georgia Pacific Corporation, International Paper Company, Irving Pulp & Paper Limited, Kvaerner Pulping Technologies, Potlatch Corporation, Stora Enso Research AB, Votorantim Celulose e Papel, Westvaco Corporation, Weyerhaeuser Company, Willamette Industries Inc., and by the Natural Sciences and Engineering Research Council of Canada (NSERC) through its Industry-Oriented Research (IOR) Grant Program