Cleaning of gaseous hydrogen chloride in a syngas by spray-dried potassium-based solid sorbents.

There are corrosive gases such as HS and HCl in a coal- or biomass-derived syngas. HCl can be removed by NaCO or KCO 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 post-combustion CO capture. Both fresh and spent CO 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 °C under an ambient pressure. Both fresh and spent CO 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 bench-scale 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 °C and 20 bar. It could be concluded that both fresh and spent spray-dried potassium-based CO sorbents could be utilized as a disposable HCl sorbent for hot syngas cleaning. [ABSTRACT FROM AUTHOR]