Aluminosilicate sorbents for control of alkali vapors during coal combustion and gasification

W. A. Punjak, Farhang Shadman

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Kaolinite is found to be a suitable sorbent for the removal of alkali from hot flue gases. The kinetics and mechanism of adsorption of NaCl vapor on kaolinite were studied at 800°C under both nitrogen and simulated flue gas (SFG) atmospheres. Under nitrogen, both chlorine and sodium were retained by the sorbent; however, under the simulated flue gas, only sodium was retained. In both cases the adsorption was irreversible. High-resolution scanning Auger analysis of kaolinite particles indicated the formation of a product layer during adsorption. Under the SFG atmosphere the product layer appears to be nephelite, a stable sodium aluminosilicate compound. The rate of adsorption dropped with the increase in alkali loading, and a maximum saturation limit was observed. An analytical model is presented that facilitates the extraction of fundamental kinetic information from experimental results.

Original languageEnglish (US)
Pages (from-to)702-708
Number of pages7
JournalEnergy and Fuels
Issue number5
Publication statusPublished - Jan 1 1988


ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Energy Engineering and Power Technology
  • Fuel Technology

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