Observations on the dynamics and efficiency of sootblowing in kraft recovery furnaces .1. Dynamics

Flue gas and steam temperature data collected on-line using infrared pyrometers and thermocouples were used to examine the dynamics ard effectiveness of sootblowing. Detailed analysis of heat transfer data indicated that artifacts or anomalies in the fouling calculations could be attributed to two sources: (a) short-term peaks in steam temperatures and drops in the measured gas temperature caused by sootblower activity, and (b) time delays in the steam temperature increase through the primary and secondary superheaters, caused by heat absorption by the tube mass. Similar artifacts have been observed in commercial sootblowing control systems. Averaging calculations over a two-hour interval (the approximate time for a sootblowing cycle in this recovery furnace) was found to eliminate these short-term aberrations and facilitate analyses of alternative sootblowing strategies and the effects of furnace firing conditions on fouling rates.