Printer Friendly

Dust and flue gas chemistry during rapid changes in the operation of black liquor recovery boilers part II--dust composition.

Application: This work adds insights on the topic of dust composition in kraft recovery boilers.

This paper is the second of three papers on the dust and flue gas chemistry of two kraft recovery boilers. It reports results of changes in fume composition, especially the behavior of potassium (K) and chloride (Cl) during rapid changes in boiler load. For the first time, dust concentrations and composition (K, Cl) and the size distributions of fume were measured online during changes in boiler dynamics. We also analyzed size-fractionated dust samples.

In these dynamic tests the dust composition [Na, K, and Cl] behaved about the same in the two boilers. Both boilers burned softwood liquor, but the dry solids contents of the black liquor were different. Between 6% and 9% of the input sodium was released in fume. Some 11%-15% of input potassium and 25%-35% of input chloride were found in fume.

The release of sodium from the char bed surface during the total interruption of black liquor flow was about 300 mg Na/s per floor square meter in both boilers. In boiler B, the increase in potassium content of dust during the liquor stop test indicated differences in the volatilization rates or mechanisms of potassium as compared to sodium. The in-flight release of sodium and potassium from liquor droplets was the main source for fume formation. In-flight release may also be the main source for sulfur release.

During the complete interruption of black liquor flow, particle size distribution moved towards smaller size fractions. The composition of size fractionated dust samples (Na, K, Cl, S[O.sub.4] C[O.sub.3]) analyzed either with IC and ICP-MS or SEM/EDXA showed equal trends as the operating conditions of the boilers were changed.

Tamminen, Lauren, and Hupa are with Abo Akademi University, Process Chemistry Group, c/o Combustion and Materials Chemistry, Turku, Finland; Janka is with Kvaerner Pulping Oy, Tampere, Finland; email Tamminen at tarja.tamminen@abo.fi or tarja.tamminen@enwin.fi.
COPYRIGHT 2002 Paper Industry Management Association
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2002, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Recovery boilers: summary of peer-reviewed material
Author:Hupa, Mikko
Publication:Solutions - for People, Processes and Paper
Date:Aug 1, 2002
Words:333
Previous Article:High-yield pulping of switchgrass.
Next Article:2002 Paper & Board Division Award winners.


Related Articles
Comprehensive model of alkali-salt deposition in recovery boilers.
Recovery boiler furnace as concentrated NCG incinerator.
Fireside behavior of black liquors containing boron.
Dust and flue gas chemistry during rapid changes in the operation of black liquor recovery boilers: Part 1--dust formation.
Partial autocausticizing of kraft smelt with sodium borates--Part I: effects on recovery boiler performance.
Dust and flue gas chemistry during rapid changes in the operation of black liquor recovery boilers--Part 3: gaseous emissions.
Dynamic modeling of potassium and chloride in the recovery area.
A pulp mill toolkit: new equipment and operating methods can help mills tackle common pulp mill problems.
Corrosion in lower furnace of kraft recovery boilers--in-situ characterization of corrosive environments.
Summaries of October 2004 peer-reviewed papers.

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters