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.
The dissociation kinetics of H2S over an alumina supported Co-Mo sulphide catalyst
In this study, a high surface area 4Co∶6Mo∶100γ-Al2O3 sulphide prepared using precipitation from homogeneous solution (PFHS) has been used for the catalytic splitting of hydrogen sulphide into H2 and elemental sulphur. The activity of this new formulation was significantly better than previously reported recipes. Kinetic data collected over a wide range of H2S partial pressures between 883 and 983 K revealed that, although the decomposition followed a first-order law, a mechanism involving H2S adsorption on co-ordinative unsaturation sites of the Co-Mo sulphide catalyst gave a Langmuir-Hinshelwood rate expression that yielded satisfactory model parameters. In particular, the scission of the surface H-S bond appeared to be the rate determining step.
Kinetics of thermal, non-catalytic decomposition of hydrogen sulphide
Abstract The reaction kinetics of the thermal, non-catalytic decomposition of H 2 S in a non-isothermal flow reactor was studied at pressures of 1.3–3.0 atm, temperatures of 600–800°C, and specific flow rates of 3.4 × 10 −4 −3.6 × 10 −3 mol/(cm 2 s). The effects of the temperature, pressure and space velocity on the conversion and reaction rates were investigated. The overall kinetics of the process are considered as the difference of the rates of the forward reaction of H 2 S decomposition and the reverse reaction of H 2 S synthesis from hydrogen and sulphur. Activation energies of 46.8 and 25.1 kcal/mol were yielded for the decomposition and synthesis of H 2 S, respectively. A free-radical mechanism has been suggested to explain the decomposition paths, on the basis of the results of this study.