Competition for Sodium and Toxic Metals Capture on Sorbents

Davis, Sheldon B.; Gale, Thomas K.; Wendt, Jost O.L.

doi:10.1080/027868200303849

Cited by 30 publications

(35 citation statements)

References 5 publications

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“…Addition of 250 ppm Cl 2 decreases the cesium sorption from the baseline value of approximately 70% to 40%. As discussed above, this is consistent with data on the effect of chlorine on lead and sodium sorption by kaolinite (34,36) and with the equilibrium predictions, albeit with possible kinetic limitations. Addition of 500 ppm SO 2 also reduces cesium sorption from approximately 70 to 30%.…”

Section: Measured Effects Of Chlorine and Sulfur Additionsupporting

confidence: 79%

“…Kaolinite, a natural mineral composed of silica and alumina (Al 2 O 3 ·2SiO 2 ·2H 2 O), has been shown to be an effective sorbent for the high temperature capture of vapor-phase lead, cadmium, and sodium (32,33,34,35,36,37,38,39). Kaolinite also has the advantages that it is compatible with subsequent vitrification and cement processes.…”

Section: Sorbent Technologymentioning

confidence: 99%

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Isolation of Metals from Liquid Wastes: Reactive Scavenging in Turbulent Thermal Reactors

Linak¹

2004

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Section: Measured Effects Of Chlorine and Sulfur Additionsupporting

confidence: 79%

Section: Sorbent Technologymentioning

confidence: 99%

Isolation of Metals from Liquid Wastes: Reactive Scavenging in Turbulent Thermal Reactors

Linak¹

2004

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“…It was previously assumed (Mwabe and Wendt 1996;Davis et al 2000) that the majority of sodium/kaolinite reaction products formed at high temperatures (1000…”

Section: Solubility Of Reaction Product For Na/kaolinite Systemmentioning

confidence: 99%

“…The capture of lead vapor by disperse kaolinite aerosol has been investigated by Scotto et al (1992) and Davis and Wendt (2000). Evidence of previously molten lead/kaolinite product particles was observed at all temperatures investigated (Davis and Wendt 2000a).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms and Models Describing Sodium and Lead Scavenging by a Kaolinite Aerosol at High Temperatures

Gale

Wendt

2003

Aerosol Science and Technology

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High temperature mechanisms of interaction between a dispersed kaolinite aerosol and vaporized sodium and lead were investigated using experimental data obtained from an 18 kW downflow furnace. The validity of using aerosol size fractionation to determine the extent of reaction between metal and substrate was confirmed through a series of specialized tests. The reaction stoichiometries for the Na/kaolinite and Pb/kaolinite systems were found to differ from literature values but were similar to each other. New light was shed on the nature of the reaction products for the Na/kaolinite and Pb/kaolinite systems, and for semivolatile metal/kaolinite sorbent systems in general. Modified reaction mechanisms were developed that accommodate key-observed processes (i.e., both enhancing and inhibitory substrate-melting processes). Rate coefficients for each system were quantitatively determined. Mechanisms are interpreted in the light of known information on the structure and nature of kaolin clay and based on observed phase transformations of the Na/kaolinite and Pb/kaolinite systems. The new models for high temperature Na/kaolinite and Pb/kaolinite interactions compared well to both new and literature data. These models can be used to predict and optimize the scavenging of vaporized sodium and lead by kaolinite mineral particles in fossil fuel-fired systems and waste incinerators.

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“…While the mechanisms for reactive capture of Pb, Cd, and Na from single-and multi-metal systems have been greatly elucidated for temperatures above 1000 °C, including detailed quantitative kinetics and rate constants, most of the previous work has been directed toward incineration applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The models developed earlier [1][2][3]21] to describe the heterogeneous capture mechanisms within incinerator effluent also apply to syngas applications, insofar as the conditions overlap.…”

Section: Introductionmentioning

confidence: 99%

Trace-Metal Scavenging from Biomass Syngas with Novel High-Temperature Sorbents

Gale

Walsh

2007

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EXECUTIVE SUMMARYEffective syngas cleanup is one of the remaining major technical challenges yet to be resolved and one that will provide the most benefit to the suite of bio-thermochemical process technologies. Beyond tars and acid gases, which are themselves a significant detriment to reforming catalysts and associated equipment, semi-volatile metals can also damage cleanup systems, catalysts, and contaminate the fungible products. Metals are a difficult challenge to deal with whether using hot-gas filtration or low-temperature processing. Even though most of the metal tends to condense before the barrier filter of hot-gas cleanup systems, some small percentage of the metal (large enough to damage syngas-reforming catalysts, the candle filters themselves, and gas turbine blades) does pass through these barrier filters along with the clean syngas. Low-temperature processing requires expensive measures to remove metals from the process stream. Significant costs are required to remove these metals and if they are not removed before contacting the catalyst, they will significantly reduce the life of the catalyst.One approach to solving the metals problem is to use high-temperature sorbents to capture all of the semi-volatile metals upstream of the barrier filter, which would prevent even small amounts of metal from passing through the filter with the clean syngas. High Temperature sorbents have already been developed that have been shown to be effective at capturing semi-volatile metals from vitiated combustion effluent, i.e., high-temperature flue gas. The objective on this project was to evaluate these same sorbents for their ability to scavenge metals from inert, reducing, and real syngas environments. Subsequently, it was the objective of this project to develop designer sorbents and an injection technology that would optimize the effectiveness of these sorbents at capturing metals from syngas, protecting the barrier filters from damage, and protecting the catalysts and other downstream equipment from damage. Finally, the high-temperature sorbent technology would be expanded to look at the role that these sorbents play in relation to tars and acid gases, which are the other significant pollutants within syngas. In addition to the technology development work described above, all of the information obtained in this work was to be incorporated into a syngas speciation model, which would allow direct prediction of transformations that occur in syngas as it passes from the gasifier and the sorbent-injection section and through the barrier filters.Unfortunately, Congressional budget cuts prevented most of this work from being accomplished. Hopefully, additional funds will be provided to this work in the future, which will allow its completion. However, at the halting point of this project, the following has been accomplished.A major initial objective of the project was accomplished, which was to determine whether or not high-temperature sorbents found to work within vitiated air might also work in an inert environme...

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Competition for Sodium and Toxic Metals Capture on Sorbents

Cited by 30 publications

References 5 publications

Isolation of Metals from Liquid Wastes: Reactive Scavenging in Turbulent Thermal Reactors

Isolation of Metals from Liquid Wastes: Reactive Scavenging in Turbulent Thermal Reactors

Mechanisms and Models Describing Sodium and Lead Scavenging by a Kaolinite Aerosol at High Temperatures

Trace-Metal Scavenging from Biomass Syngas with Novel High-Temperature Sorbents

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