skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Attrition-enhanced sulfur capture by limestone particles in fluidized beds

Abstract

Sulfur capture by limestone particles in fluidized beds is a well-established technology. The underlying chemical and physical phenomena of the process have been extensively studied and modeled. However, most of the studies have been focused on the relatively brief initial stage of the process, which extends from a few minutes to hours, yet the residence time of the particles in the boiler is much longer. Following the initial stage, a dense product layer will be formed on the particle surface, which decreases the rate of sulfur capture and the degree of utilization of the sorbent. Attrition can enhance sulfur capture by removing this layer. A particle model for sulfur capture has been incorporated with an attrition model. After the initial stage, the rate of sulfur capture stabilizes, so that attrition removes the surface at the same rate as diffusion and chemical reaction produces new product in a thin surface layer of a particle. An analytical solution for the conversion of particles for this regime is presented. The solution includes the effects of the attrition rate, diffusion, chemical kinetics, pressure, and SO{sub 2} concentration, relative to conversion-dependent diffusivity and the rate of chemical reaction. The particle model results in models thatmore » describe the conversion of limestone in both fly ash and bottom ash. These are incorporated with the residence time (or reactor) models to calculate the average conversion of the limestone in fly ash and bottom ash, as well as the efficiency of sulfur capture. Data from a large-scale pressurized fluidized bed are compared with the model results.« less

Authors:
;  [1]
  1. VTT Technical Research Center of Finland, Jyvaskyla (Finland)
Publication Date:
OSTI Identifier:
20885706
Resource Type:
Journal Article
Resource Relation:
Journal Name: Industrial and Engineering Chemistry Research; Journal Volume: 46; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; LIMESTONE; DESULFURIZATION; FLUIDIZED-BED COMBUSTION; WEAR; MATHEMATICAL MODELS; SURFACES; PARTICLES; COAL; FLY ASH; ASHES; PRESSURIZATION; SULFATION

Citation Formats

Saastamoinen, J.J., and Shimizu, T. Attrition-enhanced sulfur capture by limestone particles in fluidized beds. United States: N. p., 2007. Web. doi:10.1021/ie060570t.
Saastamoinen, J.J., & Shimizu, T. Attrition-enhanced sulfur capture by limestone particles in fluidized beds. United States. doi:10.1021/ie060570t.
Saastamoinen, J.J., and Shimizu, T. Wed . "Attrition-enhanced sulfur capture by limestone particles in fluidized beds". United States. doi:10.1021/ie060570t.
@article{osti_20885706,
title = {Attrition-enhanced sulfur capture by limestone particles in fluidized beds},
author = {Saastamoinen, J.J. and Shimizu, T.},
abstractNote = {Sulfur capture by limestone particles in fluidized beds is a well-established technology. The underlying chemical and physical phenomena of the process have been extensively studied and modeled. However, most of the studies have been focused on the relatively brief initial stage of the process, which extends from a few minutes to hours, yet the residence time of the particles in the boiler is much longer. Following the initial stage, a dense product layer will be formed on the particle surface, which decreases the rate of sulfur capture and the degree of utilization of the sorbent. Attrition can enhance sulfur capture by removing this layer. A particle model for sulfur capture has been incorporated with an attrition model. After the initial stage, the rate of sulfur capture stabilizes, so that attrition removes the surface at the same rate as diffusion and chemical reaction produces new product in a thin surface layer of a particle. An analytical solution for the conversion of particles for this regime is presented. The solution includes the effects of the attrition rate, diffusion, chemical kinetics, pressure, and SO{sub 2} concentration, relative to conversion-dependent diffusivity and the rate of chemical reaction. The particle model results in models that describe the conversion of limestone in both fly ash and bottom ash. These are incorporated with the residence time (or reactor) models to calculate the average conversion of the limestone in fly ash and bottom ash, as well as the efficiency of sulfur capture. Data from a large-scale pressurized fluidized bed are compared with the model results.},
doi = {10.1021/ie060570t},
journal = {Industrial and Engineering Chemistry Research},
number = 4,
volume = 46,
place = {United States},
year = {Wed Feb 14 00:00:00 EST 2007},
month = {Wed Feb 14 00:00:00 EST 2007}
}