Sootblowers in a kraft recovery boiler consumes a large amount of valuable high-pressure steam to maintain high thermal efficiency and prevent costly unscheduled shutdowns due to plugging of flue gas passages. For the past eight years, extensive research and mill trials have been carried out to explore the feasibility of utilizing less expensive low pressure steam for sootblowing. Results of numerous laboratory experiments, Computational Fluid Dynamic (CFD) simulations, and several mill trials have shown that low pressure sootblowing is technically and practically feasible, providing that the sootblower is properly designed and its nozzles are engineered to produce a cleaning power that is comparable to that of high pressure sootblowers. Weyerhaeuser has implemented the first complete low pressure sootblowing system on a new 6.3 million lb/day (2,860 ton/day) DBLS recovery boiler. The steam pressures at the sootblower poppet valve range from 107 psig (7.4 bar) in the economizer sections to 170 psig (12 bar) in the superheaters. This paper discusses the underlying technology of low pressure sootblowing, its full implementation at Weyerhaeuser -Valliant Mill, the cleaning performance, and the economic benefits of the system.
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