Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution

Søren Kiil, Jan Erik Johnsson, Kim Dam-Johansen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools. In this work, a critical examination of the models was conducted. The survey revealed that the models rely on the use of adjustable parameters in order to match experimental data. To investigate this, a simple particle model was set up. Model predictions were compared to experi-mental data for three different Danish limestone types with very different particle size distributions (PSDs). All limestones were of a high purity. Model predictions were found to be qualitatively in good agreement with experimental data without any use of adjustable parameters. Deviations between measurements and simulations were attributed primarily to the PSD measurements of the limestone particles, which were used as model inputs. The PSDs, measured using a laser diffrac-tion-based Malvern analyser, were probably not representative of the limestone samples because agglomeration phenomena took place when the particles were suspended in a liquid solution. The measured PSDs were sensitive to the addition of a dispersing agent, the dispersion time, and the presence of ultrasound. It was found that the different PSDs influenced the simulated rate of dis-solution significantly (i.e. from below to above the measured dissolution rate). The results of this work show that a representative PSD is essential in order to model the rate of dissolution of lime-stone particles accurately.
Original languageEnglish
JournalPowerPlant Chemistry
Volume1
Issue number5
Pages (from-to)26-30
ISSN1438-5325
Publication statusPublished - 1999

Cite this

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title = "Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution",
abstract = "In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools. In this work, a critical examination of the models was conducted. The survey revealed that the models rely on the use of adjustable parameters in order to match experimental data. To investigate this, a simple particle model was set up. Model predictions were compared to experi-mental data for three different Danish limestone types with very different particle size distributions (PSDs). All limestones were of a high purity. Model predictions were found to be qualitatively in good agreement with experimental data without any use of adjustable parameters. Deviations between measurements and simulations were attributed primarily to the PSD measurements of the limestone particles, which were used as model inputs. The PSDs, measured using a laser diffrac-tion-based Malvern analyser, were probably not representative of the limestone samples because agglomeration phenomena took place when the particles were suspended in a liquid solution. The measured PSDs were sensitive to the addition of a dispersing agent, the dispersion time, and the presence of ultrasound. It was found that the different PSDs influenced the simulated rate of dis-solution significantly (i.e. from below to above the measured dissolution rate). The results of this work show that a representative PSD is essential in order to model the rate of dissolution of lime-stone particles accurately.",
author = "S{\o}ren Kiil and Johnsson, {Jan Erik} and Kim Dam-Johansen",
year = "1999",
language = "English",
volume = "1",
pages = "26--30",
journal = "PowerPlant Chemistry",
issn = "1438-5325",
publisher = "PowerPlant Chemistry GmbH",
number = "5",

}

Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution. / Kiil, Søren; Johnsson, Jan Erik; Dam-Johansen, Kim.

In: PowerPlant Chemistry, Vol. 1, No. 5, 1999, p. 26-30.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Modelling of Limestone Dissolution in Wet FGD Systems: The Importance of an Accurate Particle Size Distribution

AU - Kiil, Søren

AU - Johnsson, Jan Erik

AU - Dam-Johansen, Kim

PY - 1999

Y1 - 1999

N2 - In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools. In this work, a critical examination of the models was conducted. The survey revealed that the models rely on the use of adjustable parameters in order to match experimental data. To investigate this, a simple particle model was set up. Model predictions were compared to experi-mental data for three different Danish limestone types with very different particle size distributions (PSDs). All limestones were of a high purity. Model predictions were found to be qualitatively in good agreement with experimental data without any use of adjustable parameters. Deviations between measurements and simulations were attributed primarily to the PSD measurements of the limestone particles, which were used as model inputs. The PSDs, measured using a laser diffrac-tion-based Malvern analyser, were probably not representative of the limestone samples because agglomeration phenomena took place when the particles were suspended in a liquid solution. The measured PSDs were sensitive to the addition of a dispersing agent, the dispersion time, and the presence of ultrasound. It was found that the different PSDs influenced the simulated rate of dis-solution significantly (i.e. from below to above the measured dissolution rate). The results of this work show that a representative PSD is essential in order to model the rate of dissolution of lime-stone particles accurately.

AB - In wet flue gas desulphurisation (FGD) plants, the most common sorbent is limestone. Over the past 25 years, many attempts to model the transient dissolution of limestone particles in aqueous solutions have been performed, due to the importance for the development of reliable FGD simu-lation tools. In this work, a critical examination of the models was conducted. The survey revealed that the models rely on the use of adjustable parameters in order to match experimental data. To investigate this, a simple particle model was set up. Model predictions were compared to experi-mental data for three different Danish limestone types with very different particle size distributions (PSDs). All limestones were of a high purity. Model predictions were found to be qualitatively in good agreement with experimental data without any use of adjustable parameters. Deviations between measurements and simulations were attributed primarily to the PSD measurements of the limestone particles, which were used as model inputs. The PSDs, measured using a laser diffrac-tion-based Malvern analyser, were probably not representative of the limestone samples because agglomeration phenomena took place when the particles were suspended in a liquid solution. The measured PSDs were sensitive to the addition of a dispersing agent, the dispersion time, and the presence of ultrasound. It was found that the different PSDs influenced the simulated rate of dis-solution significantly (i.e. from below to above the measured dissolution rate). The results of this work show that a representative PSD is essential in order to model the rate of dissolution of lime-stone particles accurately.

M3 - Journal article

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JO - PowerPlant Chemistry

JF - PowerPlant Chemistry

SN - 1438-5325

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