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Licensed Unlicensed Requires Authentication Published by De Gruyter November 21, 2014

Dissolution kinetics of sorbents and effect of additives in wet flue gas desulfurization

  • Lawrence Koech , Ray Everson , Hein Neomagus and Hilary Rutto EMAIL logo

Abstract

Flue gas desulfurization (FGD) technology has been adopted by a number of power stations for the removal of sulfur dioxide (SO2) from flue gas. The wet FGD system is the most commonly used process because of high SO2 removal efficiency and because of the availability of the sorbent used. This paper emphasizes the wet FGD process and the different types of sorbents used. Sorbent dissolution in the wet FGD process plays a significant role in the overall performance of the system. Factors such as temperature, solid-to-liquid ratio, pH, particle size, and additives can be optimized to improve the dissolution rate in the wet FGD system. Additives such as organic acids and inorganic salts can improve the dissolution rate and the desulfurization efficiency of the sorbent. Dissolution kinetics gives an understanding of the effects of reaction variables on the dissolution rate. The dissolution process is a heterogeneous reaction system consisting of fluid reactants and solid particles. This is best described using the shrinking core model that considers a reducing solid particle size as the reaction takes place.


Corresponding author: Hilary Rutto, Department of Chemical Engineering, Vanderbijlpark Campus, Vaal University of Technology, Private Bag X021, Vanderbijlpark, South Africa 1900, e-mail:

Nomenclature
rc

Final particle radius

Ri

Initial particle radius

Ki

Mass transfer coefficient

ρB

Molar density of B in the solid

R

Universal gas constant

X

Fractional conversion of a sphere

b

Stoichiometric coefficient

CA

Bulk concentration

Ea

Apparent activation energy

Ko

Pre-exponential factor

Kr

Dissolution rate constant

Acknowledgments

The authors would like to thank Eskom for the sponsorship of the project through the tertiary education support program.

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Received: 2014-6-7
Accepted: 2014-9-18
Published Online: 2014-11-21
Published in Print: 2014-12-1

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