From 1 - 2 / 2
  • Categories  

    Data derived from UKCCSRC Call 2 Project C2-181. The journal article can be found at https://doi.org/10.1016/j.ijhydene.2017.05.222. The sorption enhanced steam reforming (SE-SMR) of methane over the surface of 18 wt. % Ni/Al2O3 catalyst and using CaO as a CO2-sorbent is simulated for an adiabatic packed bed reactor. The developed model accounts for all the aspects of mass and energy transfer, in both gas and solid phase along the axial direction of the reactor. The process was studied under temperature and pressure conditions used in industrial SMR operations. The simulation results were compared with equilibrium calculations and modelling data from literature. A good agreement was obtained in terms of CH4 conversion, hydrogen yield (wt. % of CH4 feed), purity of H2 and CO2 capture under the different operation conditions such as temperature, pressure, steam to carbon ratio (S/C) and gas mass flux. A pressure of 30 bar, 923 K and S/C of 3 can result in CH4 conversion and H2 purity up to 65% and 85% respectively compared to 24% and 49% in the conventional process.

  • Categories  

    Data derived from UKCCSRC Call 2 Project C2-181. The journal article can be found at http://dx.doi.org/10.1016/j.fuel.2017.03.072. Sorption enhanced chemical looping steam reforming of methane (SE-CLSR) relies on the exothermicity of both a metal catalyst’s oxidation and the in situ CO2 capture by carbonation onto a solid sorbent to provide the heat demand of hydrogen (H2) production by steam reforming while generating a nearly pure H2 product. A brief thermodynamic analysis to study the main features of the SE-CLSR process is done prior to the reactor modelling work. Later, one dimensional mathematical model of SE-CLSR process in the packed bed configuration is developed using gPROMS model builder 4.1.0 under the adiabatic conditions. This model combines reduction of the NiO catalyst with the steam reforming reactions, followed by the oxidation of the Ni-based reduced catalyst. The individual models of NiO reduction, steam reforming with in situ CO2 capture on Ca-sorbent, and Ni re-oxidation are developed by using kinetic data available in literature and validated against previous published work. The model of SE-CLSR is then applied to simulate 10 alternative cycles of the fuel and air feed in the reactor. The performance of the model is studied in terms of CH4 conversion, CO2 capture efficiency, purity and yield of H2. The sensitivity of the process is studied under the various operating conditions of temperature, pressure, molar steam to carbon ratio (S/C) and mass flux of the gas phase. In this work, the operating conditions used for the production of H2 represent realistic industrial production conditions. The sensitivity analysis demonstrates that the developed model of SE-CLSR process has the flexibility to simulate a wide range of operating conditions of temperature, pressure, S/C and mass flux of the gas phase.