Thermodynamic Possibilities and Limits for Producer Gas Desulfurization and HCL Related Interferences for Zn, Mn, Ce and La Based Sorbents of Sulfur Compounds

The study is concentrated on thermodynamic analyses of gas desulfurization process (deep removal of H2S, COS, thiophene) by selected solid sorbents (ZnO, MnO, CexOy and La2O3) and on interferences caused by presence of hydrogen halides in a temperature range 500-1100 K. The results show that theoretically Ce2O3 and La2O3 are the best sorbents for sulfur compounds at temperatures over approx. 700 K. The CexOy, La2O3 and MnO based sorbents can suffer from significant interferences caused by higher concentrations of HCl and HF in gas phase. The thermodynamic equilibria suggest that removal of HCl (HF) by soda based sorbents at temperatures 650 – 850 K is practically without interferences from sulfur compounds. The common alkali carbonates are less suitable than the calcium based (Ca (OH)2, CaCO3) sorbents for deep removal of HF.