Continuous dust measurement as an indication of sootblowing performance in a recovery boiler

In this paper, a new method is introduced for continuously measuring the amt. and compn. of dust (K, Cl) in the flue gas of recovery boilers.  This system makes a tool for various real time observations of fine dust behavior.  In this study, the dust analyzer was demonstrated to measure sootblowing performance at one recovery boiler.  The sootblowing sequence and the frequency of each sootblower-​pair could be detected as variations in the total dust concn.  The amt. of sootblown fine dust was 9 to 28​% of the total amt. of precipitator dust due to dust compn., boiler cleanability and operating conditions.  The internal precipitator dust recycle varied from 93 to 220 tons​/d being 5.3-​9.5​% of the boiler load (tons BLS​/d)​.  Also, interesting variations were obsd. in potassium and chloride content of the dust removed from surfaces during sootblowing.  This continuous dust measuring system makes a tool for studying the effectiveness of various sootblowing strategies.  The required operating time and frequency of individual sootblowers in the boiler bank and economizer regions can be studied and optimized.  It is possible to resolve the effects of operational variations on the amt. of precipitator dust recycle.  Furthermore, a major benefit of the described online measuring system of dust is that the responses can be seen immediately, and the outputs can be connected to the process control system of a mill, together with other process variables.