Recovery boiler sootblowers: History and technological advances

Sootblowing technology used in recovery boilers originated from that used in coal-fired boilers. It start - ed with manual cleaning with hand lancing and hand blowing, and evolved slowly into online sootblowing using retract - able sootblowers. Since 1991, intensive research and development has focused on sootblowing jet fundamentals and deposit removal in recovery boilers. The results have provided much insight into sootblower jet hydrodynamics, how a sootblower jet interacts with tubes and deposits, and factors influencing its deposit removal efficiency, and have led to two important innovations: fully-expanded sootblower nozzles that are used in virtually all recovery boilers today, and the low pressure sootblowing technology that has been implemented in several new recovery boilers. The availability of pow - erful computing systems, superfast microprocessors and data acquisition systems, and versatile computational fluid dynamics (CFD) modeling capability in the past two decades has also contributed greatly to the advancement of sootblow - ing technology. High quality infrared inspection cameras have enabled mills to inspect the deposit buildup conditions in the boiler during operation, and helped identify problems with sootblower lance swinging and superheater platens and boiler bank tube vibrations. As the recovery boiler firing capacity and steam parameters have increased markedly in re - cent years, sootblowers have become larger and longer, and this can present a challenge in terms of both sootblower design and operation.This work was conducted as part of the research program on “Increasing Energy and Chemical Recovery Efficiency in the Kraft Process,” jointly supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and a consortium of the following companies: Andritz, AV Nackawic, Babcock & Wilcox, Boise, Carter Holt Harvey, Cellulose Nipo- Brasileira, Clyde-Bergemann, DMI Peace River Pulp, Eldorado, ERCO Worldwide, Fibria, FP Innovations, International Paper, Irving Pulp and Paper, Kiln Flame Systems, Klabin, MeadWestvaco, StoraEnso Research, Suzano, Tembec, Tolko Industries, and Valmet. The authors also wish to acknowledge Diamond Power International for its past support of the sootblowing research program at the University of Toronto