Properties of particles attaining the heat exchangers in kraft recovery boiler

Pirita Mikkanen, Esko Kauppinen, Esa Vakkilainen, Kari Saviharju

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

2 Citations (Scopus)

Abstract

In order to predict the deposit formation in the recovery boiler, advanced modelling tools are required. Current models for the deposit formation need experimental data on the coarse fly ash particles (diameter >3 µm), since no validated formation model has been reported for them. On the other hand, a formation model for the fine fume particles (diameter <3 µm) has been established and validated. In this work, the characteristics of recovery boiler flue gas particles were studied experimentally in the furnace. The particles were extracted from the flue gas with a quench probe and subsequently collected on a planar filter or size classified with a Berner type low pressure impactor. In addition, individual particles were collected with a settling probe and a cooled grid sampler. The particle characterization was carried out by analyzing the samples with ion chromatography, X-ray absorption of free structure, and a scanning electron microscope along with an energy dispersive X-ray analysis system. The fine particles in the furnace of typical Finnish boilers are mainly Na2SO4, double sulphate of Na and K, and NaCl. No KCl was detected. The chemical composition of the coarse particles in the furnace suggests that they are unburned particle residues or originate from impurities in black liquor. The coarse particles deposit along the flue gas passage and they are not detected at the ESP inlet. Nevertheless, as reported earlier, the particle size distribution is bimodal at the ESP inlet. At this site, the coarse particles are not unburned residues, but mostly large agglomerates of fine particles re-entrained from the heat exchangers.
Original languageEnglish
Title of host publication1998 International Chemical Recovery Conference Proceedings
PublisherTAPPI Press
Pages983-987
Volume3
Publication statusPublished - 1998
MoE publication typeB3 Non-refereed article in conference proceedings
Event1998 TAPPI International Chemical Recovery Conference - Tampa, United States
Duration: 1 Jun 19984 Jun 1998

Conference

Conference1998 TAPPI International Chemical Recovery Conference
Country/TerritoryUnited States
CityTampa
Period1/06/984/06/98

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