Operating Experience of XL-Size Recovery Boilers, 2001 Engineering / Finishing & Converting Conference Proceedings

J. Mäntyniemi, K. Haaga--In the 90’s most new pulp lines built throughout the world were larger than those built in the past. These new lines were designed with yearly capacities of 500,000 ADT or higher. New developments in technology made it possible to take advantage of the economy of scale when building these new pulp lines. Obviously the recovery boiler had to grow in order to meet the production capacity in the large new single line pulp mill. In a very short period the capacity of a large recovery boiler leaped from 2000 tds/day to 3000 tds/day, a 50% scale-up. To-date more than 30 operating years of experience with these extra large (XL) recovery boilers has been accumulated.

This Paper will discuss the operational experience on the XL size recovery boilers in Scandinavia and South East Asia. This will include discussion regarding the development of the recovery boiler technology that made the scale up possible. Also, discussions regarding the mechanical design and operation of these large boilers will be presented, including lessons learned over the past 10 years. Operational experience will include various types of liquor as well as the effect of firing strong and weak non-condensable gases on boiler performance and emissions.