Alkali removal from hot flue gas by solid sorbents in pressurized pulverized coal combustion

Escobar, Isabel C.; Oleschko, Holger; Wolf, Karl-Josef; Müller, Michael

doi:10.1016/j.powtec.2007.03.001

Cited by 22 publications

(17 citation statements)

References 5 publications

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“…Several authors found aluminosilicates such as bauxite and kaolinite to be suitable alkali sorbents. These same materials were shown to be effective in combustion atmospheres, removing alkalis to as little as 50 ppbv through formation of stable alkali silicate compounds. Alumina can also act as a physical sorbent: activated alumina was found to adsorb NaCl vapour with 98% efficiency to a loading of 6.20 mg/g .…”

Section: Emissions and Abatementmentioning

confidence: 99%

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Dolan

Ilyushechkin

McLennan

et al. 2011

Asia-Pacific J Chem Eng

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Alkalis are highly corrosive towards materials associated with syngas processing and utilisation, including ceramic particulate filters and metallic components. The removal of alkali species, consequently, is an important step in the cleaning of coal and biomass-derived syngas. The origins of the alkali contaminant govern the ability of specific sorbents to remove these species via chemical means. Alkali salt removal is dependent on the formation of an acid halide species, a reaction, which in the absence of H 2 O, involves hydrogen and carbon dioxide. This reaction becomes increasingly unfavourable above 1000 C, but below this temperature, equilibrium conversion approaches 100%. The fluxing of a gasifier slag, which is often necessary to reduce viscosity to a level that allows tapping, reduces its ability to absorb alkali halides. This effect however was not observed with oxide-based alkalis, which shows strong affinity for gasifier slag regardless of fluxing, up to 1600 C. Furthermore, there is a potential for removal of boron and phosphorous contaminants using these same sorbents. In a complete high-temperature, dry gas cleaning sequence, alkali removal would ideally be undertaken prior (or simultaneously to) halide removal and prior to sulfur removal.

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Section: Emissions and Abatementmentioning

confidence: 99%

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Dolan

Ilyushechkin

McLennan

et al. 2011

Asia-Pacific J Chem Eng

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“…With the presence of water vapor, the alumosilicate network breaks up and alkali atoms bind to the free end of a Si–O chain . The mechanism of melting‐phase sorption occurs with alumina‐ and silica‐rich getters at temperatures above 1000 °C , . Alkali atoms, which destroy the ordered form of the alumosilicate network, are included in interstitial sites of the getter matrix.…”

Section: Introductionmentioning

confidence: 99%

The Reaction Kinetics of Gaseous Alkali Capture by Kaolin in Syngas Atmosphere

Kerscher¹,

Stetka²,

Spliethoff

2018

Chem Eng & Technol

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Alumosilicate minerals are suitable sorbents at high temperatures for removing alkalis in syngas. Thermogravimetric investigations of these sorbents usually focus on the reaction mechanisms. Herein, a crucible arrangement is described that allows evaporation of the alkali source and sorption of gaseous alkali components in one temperature zone. With this experimental setup, kinetic investigations of alkali sorption are possible in a conventional thermobalance. Experiments were performed with sodium chloride as the alkali source and kaolin as the getter material. The reaction rate increased with alkali concentration and showed an exponential dependence on temperature. Thus, the Arrhenius model approach and power law model were selected for mathematical description.

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“…Simulations show an unambiguous advantage of hot desulfurization before cold, which can be seen from tab. 1 [2][3][4][5][6][7][8]. Air-blown IGCC processes were compared in [2], air-blown IGCC and oxygen-blown IGCC were compared in [3].…”

Section: Introductionmentioning

confidence: 99%

Syngas clean-up system kinetics investigation

et al. 2018

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Zinc oxide and hydrogen sulfide reaction was researched experimentally. Dynamic characteristics (solid phase mass change per time, temperature change per time inside the reactor, gas volume flow rate on inlet) were obtained for pure ZnO powder and granular sorbent Katalco 32-4-Johnson & Matthey by thermogravimetric analyzer. Pre-exponential factor, energy activation and specific mass flow rate of ZnO were numerically calculated for pure ZnO. Pure ZnO, ZnO 2 SC, and granular sorbent conversion rates were compared. Thermogravimetric experiments with pure ZnO and with ZnO 2 SC were simulated in ANSYS Fluent software. Kinetic constants were input parameters for CFD software. Simulation data and experimental results agree well on sorbent conversion diagram.

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Alkali removal from hot flue gas by solid sorbents in pressurized pulverized coal combustion

Cited by 22 publications

References 5 publications

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

Alkali, boron and phosphorous removal from coal‐derived syngas: review and thermodynamic considerations

The Reaction Kinetics of Gaseous Alkali Capture by Kaolin in Syngas Atmosphere

Syngas clean-up system kinetics investigation

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