Modeling and simulation of non-isothermal catalytic packed bed membrane reactor for H 2 S decomposition
The recovery of H2 from H2S is an economical alternative to the Claus process in petroleum and minerals processing industries. Previous studies [React. Kinet. Catal. Lett. 62 (1997) 55; Catal. Lett. 37 (1996) 167] have demonstrated that catalytic decomposition of H 2S over bimetallic sulfide can proceed at relatively higher rates than over mono-metallic systems due to chemical synergism although conversions are still thermodynamically limited. In the present study, the performance of a catalytic membrane reactor containing a packed bed of Ru–Mo sulfide catalyst has been investigated with a view to improving H2 yield beyond the equilibrium ceiling. A system of differential equations describing the non-isothermal reactor model has been solved to examine the effect of important hydrodynamic and transport properties on conversion. The results were obtained using a Pt-coated Nb membrane tube as the catalytic reactor enclosed in a quartz shell cylinder. Reynolds number for shell and tube side ( Res andRet) as well as the modified wall Peclet number, Pem, dramatically affect H2S conversions. Membrane reactor conversion rose monotonically with axial distance exceeding the equilibrium conversion by as much as eight times under some conditions. © 2000 Elsevier Science B.V. All rights reserved.
Review of Hydrogen Isotope Permeability Through Materials
This report is the first part of a comprehensive summary of the literature on hydrogen isotope permeability through materials that do not readily form hydrides. While we mainly focus on pure metals with low permeabilities because of their importance to tritium containment, we also give data on higher-permeability materials such as iron, nickel, steels, and glasses.
Thermodynamic analysis of the thermochemical decomposition of H2S in the presence of iron sulphide
The decomposition of H2S by a two-step closed loop thermochemical decomposition process was investigated. In the first step, H2S decomposes by reacting with iron sulphide to produce hydrogen and a solid solution consisting of FeS and S2. In the second step, the solid solution is decomposed at high temperature to recover sulphur and the iron sulphide which is reused in the first step. The thermodynamics of the first reaction were studied in detail by taking into account 12 gas phase chemical reactions and the phase equilibrium that is established between the sulphur in the gas and in the solid solution. The non-linear system of 13 equations, which relate the fugacities of the components at equilibrium to the equilibrium constants, were numerically solved by the Newton-Raphson iteration technique. The calculation results showed that the gas phase at equilibrium contains predominantly H2S, H2, and H2S2. The equilibrium conversion was found to decrease with increasing temperature; however, when the sulphur content of the solid solution was small, high hydrogen yields were possible even at high temperatures. 
 
 
 
On a etudie la decomposition du H2S par un procede de decomposition thermochimique a boucle fermee et bietage. Dans la premiere phase, le H2S se decompose en reagissant avec le sulfure de fer pour produire de l'hydrogene et une solution solide composee de FeS et de S2. Dans la seconde phase, la solution solide est decomposee a temperature elevee pour recuperer le soufre et le sulfure de fer qui est reutilise dans la premiere phase. On a etudie la thermodynamique de la premiere reaction en detail en considerant 12 reactions chimiques en phase gazeuse et l'equilibre de phase existant entre le soufre dans le gaz et le soufre dans la solution solide. Le systeme non lineaire de 13 equations, qui relient la fugacite des composants a l'equilibre aux constantes d'equilibre, sont resolues numeriquement par la technique d'iteration de Newton-Raphson. Les resultats des calculs montrentque la phase gazeuse a l'equilibre contient principalement du H2S, du H2 et du H2S2. On a trouve que la conversion a l'equilibre diminue avec l'augmentation de la temperature; cependant, lorsque la teneur en soufre de la solution solide est petite, des rendements eleves en hydrogene sont possibles měme a des temperatures elevees.