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Thermodynamic Interferences of HCl and HF in Producer Gas Desulfurization by Ce, La, Mn and Zn Based Solid Sorbents
Hartman, Miloslav ; Svoboda, Karel ; Pohořelý, Michael ; Šyc, Michal ; Jeremiáš, Michal ; Huang, Ch.-Y.
In our thermodynamic theoretical study we concentrated our attention on thermodynamics of gas-solid desulfurization reactions (H2S, COS, thiophene), properties of sorbents (melting point evaporation), attainable equilibrium sulfur compounds concentrations in gas at temperature 500 – 1100 K (227-827 oC) under conditions typical for producer gas composition. Similarly removal of HCl and HF by Ce, La, Zn, Mn and Ni oxides based sorbents is described and possible interferences in simultaneous sorption of HCl or HF with H2S are analyzed. Suitable conditions and sorbents are suggested for deep removal of sulfur compounds in presence of HCl. Conditions for efficient preliminary removal of HCl and HF by alkali-based sorbents (NaHCO3, K2CO3, Ca(OH)2, CaCO3) are suggested and possible interferences caused by H2S are analyzed in terms of attainable equilibrium concentrations of HCl and HF in presence of H2S. Properties of La and Ce-based sorbents for sulfur compounds are compared with Zn, Mn and Ni based sorbents in terms of efficiency and interferences caused by presence of hydrogen-halides (HCl, HF).
Plný tet: SKMBT_C22014082908320 -  PDF
Plný text: content.csg - PDF
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Multiple Sulfidation/Regeneration Cycle Tests for Advanced Fuel Conversion Process by 20 wt%Fe2O3/Al2O3 Sorbent
Huang, C.Y. ; Chyou, Y.P. ; Svoboda, Karel
In this study, 20 wt%Fe2O3/Al2O3 was used as a sorbent to perform multiple sulfidation/regeneration cycle tests in a fixed-bed reactor under simulated hot syngas conditions. The physical properties of sorbents were analyzed by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), BET, and SEM/EDS. ICP-AES results indicated that the composition of metal oxide was close to the theoretical value. Multiple sulfidation/regeneration cycle tests showed that the 20wt%Fe2O3/Al2O3 can be regenerated and thus reused after the oxidation process. Due to the sulfidation reaction, colour change of the 20 wt%Fe2O3/Al2O3 sorbent was observed, from the original red to black. After six sulfidation-regeneration cycles, the sulfur capacity of the sixth cycle remained approximately on a level of 68% of the sulfur capacity in the first cycle. The BET analysis showed that the surface area decreased as the cycle number increased. The sulfidation-regeneration cycles were coupled with endothermic-exothermic reactions, which probably caused sintering of the sorbent, decreasing its surface area and sulfur capacity.
Plný tet: SKMBT_C22014082908321 - PDF
Plný text: content.csg - PDF
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