ADSORPTION RECOVERY OF HCL AND SO2 FROM GASES USING ZEOLITES

HCl and SO2 recovery from gases using zeolite-based adsorbents (mordenite and dealuminated Y zeolite) was studied for HCl (SO2) content 0,2-6 vol. %. TT 233-296 K, PP 1-10 atm. The features of HCl and SO2 adsorption were investigated using adsorption isotherms, TPD spectra, and different regeneration procedures. Both adsorbents were stable in a multi-sysle adsoption process. Mordenite possesses the higher adsorption capacity at low HCl (SO)2 partial pressure and relatively high temperatures (> 290 K), but it can be regenerated effectively only at 400-530 K. Dealuminated Y zeolites have an advantages over mordenite at increased pressure and low temperature (233-273 K), and they can de regenerated readily by depressurization at 300-370 K. Mordenite is more suitable for temperature-swing processes (HCl recovery from H-2 in silicon production technology, SO2 adsorption from tail gases of H2SO4 plant), while dealuminated Y zeolites are more attractive for pressure-swing processes (tail gas treatment in liquid SO2 production, etc.). A process of HCl recovery from hydrogen using mordenite was realized at a pilot adsorption unit built at a silicon plant.