Thermodynamics Possibilities and Constraints for the Regeneration of Spent Solid H2S Sorbents Based on Ce-, La-, and Zn-Oxides.

0462391 - ÚCHP 2017 RIV ZA eng C - Conference Paper (international conference)
Svoboda, Karel - Leitner, J. - Brynda, Jiří - Skoblia, S. - Chyou, Y.-P. - Chen, Y.-S. - Hartman, Miloslav
Thermodynamics Possibilities and Constraints for the Regeneration of Spent Solid H2S Sorbents Based on Ce-, La-, and Zn-Oxides.
Proceedings. Cape Town: University of Pittsburgh, 2016, s. 1-11. ISBN 1-890977-33-0.
[Annual International Pittsburgh Coal Conference /33./. Cape Town (ZA), 08.08.2016-12.08.2016]
R&D Projects: GA ČR GC14-09692J
Grant - others:NSC(TW) 103-2923-E-042A-001 -MY3
Institutional support: RVO:67985858
Keywords : sorbents * regeneration * temperature
Subject RIV: CI - Industrial Chemistry, Chemical Engineering

The thermodynamic analyses are focused on suitable ways and conditions for regeneration of spent desulfurization sorbents from dry cleaning of producer gas in a temperature range 600 – 1200 K. Three sulfidic compounds (ZnS, Ce2O2S and La2O2S) were considered for regeneration to the corresponding oxides or oxy-carbonates by mild oxidation, reaction with SO2 and reaction with water vapour and CO2. Zinc sulfide can be regenerated practically only by mild oxidation either at O2/ZnS molar ration around 1.5 at temperatures between approx. 950 and 1050 K or at temperatures over 1200 K at higher O2/ZnS molar ratios. The temperature of regeneration higher than approx. 1100 K causes sintering/changes of sorbent texture. The Ce2O2S-based spent cerium sorbents are advantageously regenerated by reaction with SO2 at temperatures over 700 K (between 700 and 900 K). In this way CeO2, elemental sulfur and small concentrations of S2O are theoretically produced. If the spent Ce-sorbent contains also Ce-halides (e.g. CeCl3) , they are not decomposed by reaction with SO2. The La-based spent sulfur sorbents are restored by reaction with CO2 and H2O vapor leading to formation of La2O2CO3 and H2S. The suitable operating conditions involve temperatures between 700 and 800 K and higher operating pressures (above 1 MPa). The regeneration of La2O2S by simple oxygen oxidation is complicated by formation of very stable oxy-sulfate La2O2SO4.
Permanent Link: http://hdl.handle.net/11104/0261865