Hysteresis in autothermal methane reforming over Rh catalysts: Bifurcation analysis

Numerical analysis of the hysteresis characteristics of a fixed bed catalytic reactor carrying on autothermal methane reforming over Rh catalyst is presented. A one-dimensional heterogeneous model describing heat and mass transport and simultaneously accounting for methane combustion, steam reforming and dry reforming is adopted. Parametric continuation is performed to compute steady state solution regimes predicted by the model. Bifurcation analysis is illustrated allowing characterizing the influence of feed temperature, gas flow rate, oxygen to methane and water to methane feed ratio values on ignition and extinction. A thorough description of the physical mechanisms determining the evolution of hydrogen selectivity, maximum solid temperature and syngas production within the explored region of parameters space is presented. Particular attention is in this framework devoted to analysing the effect of water addition on reactor bifurcation behavior and performance. The illustrated characterization of hysteretic phenomena provides guidelines for process design, operation and control.