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On the diagnosis of a fouling condition in a kraft recovery boiler: combining process knowledge and data-based insights, TAPPI Journal March 2023

ABSTRACT: Fouling is still a major challenge for the operation of kraft recovery boilers. This problem is caused by accumulation of ash deposits on the surfaces of heat exchangers in the upper part of the boiler over time. The first consequence is the reduction of steam production due to loss of heat transfer and, finally, the shutdown of the boiler due to clogging. The present work investigated the operational condition of a modern kraft boiler under a critical fouling condition. This boiler had even faced a manual cleaning due to a clogging event. This analysis combined process knowledge, plant team experience, and a data-driven approach, given the complexity of the process. In this sense, historical data covering this critical period of operation were collected. After a cleaning procedure, they were used to obtain a predictive neural network model for the flue gas pressure drop in the boiler bank, which is an indirect measure of ash deposit accumulation. Once validated, it was used for sensitivity analysis, with the aim of quantifying the effects of the model inputs. Five variables out of eighteen accounted for nearly 60% of the total effect on pressure drop. Namely, primary air temperature (21.6% of the total effect) and flow rate (11.1%), black liquor flow rate (9.9%) and temperature (8.4%), and white liquor sulfidity (8.6%). The analysis of these results mainly suggested an excess of carryover, which composes the ash deposits. Recommended actions to mitigate the fouling condition involved adjustments to the primary air system before the more drastic solution of reducing the boiler load.

Journal articles
Open Access
Qualification of Welding Procedures for Duplex Stainless Ste

Qualification of Welding Procedures for Duplex Stainless Steels, 1999 Engineering Conference Proceedings

Journal articles
Open Access
TJ web enhancements, TAPPI JOURNAL, August 2002, Vol. 1(6) (

TJ web enhancements, TAPPI JOURNAL, August 2002, Vol. 1(6) (49KB)

Journal articles
Open Access
Effect of PCC filler on dewatering of fiber suspension

Effect of PCC filler on dewatering of fiber suspension, TAPPI JOURNAL, November 2006

Journal articles
Open Access
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, Novem

Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, November, 2006

Journal articles
Open Access
Linking Pulp Variations to TMP Operation by Better Selection

Linking Pulp Variations to TMP Operation by Better Selection and Treatment of Process Data

Journal articles
Open Access
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, Novem

Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, November, 2006

Journal articles
Magazine articles
Open Access
Editor's Note: An Ideal Raw Material for Pulp and Paper, TAP

Editor's Note: An Ideal Raw Material for Pulp and Paper, TAPPI JOURNAL March 2010

Journal articles
Open Access
Pulping and Papermaking Properties of Managed Second-Growth

Pulping and Papermaking Properties of Managed Second-Growth Softwoods, 1995 Pulping Conference Proceedings

Journal articles
ￌBuying Spare Parts, Paper360° September 2007

Buying spare parts, Paper360º September 2007

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