Wood-Fired Boiler Design for Minimum Emissions, High Reliability and Ability to Handle Wood Fuels of a Wide Range, 1995 Engineering Conference Proceedings

Bo Oscarsson

Kvaerner Pulping Inc.

The County of Snohomish in the State of Washington is a non-attainment area. This forced Scott Paper to look at power boiler designs with the capability of maintaining low NO, emissions. The new power boiler at Scott Worldwide in Everett, WA is designed to handle a variety of wood fuels while still maintaining low emissions, especially NO,. Since the unit is a part of the cogeneration plant tied to SPUD, the local utility, reliability and uptime is also of great importance. The unit is conservatively sized and includes a DeNOx system utilizing aqueous ammonia. The integration of the DeNOx system and the furnace was based on detailed analyses of furnace characteristics and optimum injection nozzle location. By utilizing multiple levels of air supply to the furnace, the uncontrolled NO, from the unit is minimized. This allows the residual NO, after ammonia injection to be reached without excessive consumption of ammonia and keeping the ammonia slip as low as possible.