There are corrosive gases such as H2S and HCl in a coal- or biomass-derived syngas. HCl can be removed by Na2CO3 or K2CO3 at hot temperatures. Hot syngas cleaning has the advantage of improving thermal efficiency. We investigated HCl removal by spray-dried potassium-based solid sorbents which were originally developed for postcombustion CO2 capture. Both fresh and spent CO2 sorbents were tested to confirm the applicability as a sorbent for HCl cleaning. Saturation chlorine sorption capacity was measured using a fixed-bed reactor at a temperatures of 300-
500 oC under an ambient pressure. Both fresh and spent CO2 sorbents showed saturation chlorine sorption capacity above 15 wt%. HCl removal performance of the sorbents was investigated in a micro fluidized-bed reactor and a benchscale bubbling fluidized-bed reactor. HCl concentration was lowered from 150-900 ppmv to less than 5 ppmv and from 130-390 ppmv to less than 1 ppmv in a micro fluidized-bed reactor and in a bench-scale bubbling fluidized-bed reactor, respectively, at 300-540 oC and 20 bar. It could be concluded that both fresh and spent spray-dried potassium-based CO2 sorbents could be utilized as a disposable HCl sorbent for hot syngas cleaning.
Krishnan GN, Gupta RP, Canizales A, Sheluka S, Ayala R, In: Schmidt E, Gang P, Pilz T, Dittler A, Eds. “High Temperature Gas Cleaning” Karlsruhe: G. Braun Printconsult GmbH, 405, 1996
Nunokawa M, Kobayashi M, Shirai H, In: Dittler, Hemmer AG, Kasper G, Eds. “High Temperature Gas Cleaning, Vol. II” Karlsruhe: G. Braun Printconsult GmbH, 684, 1999