Kinetic determination of chemical looping combustion reactions in a continuous stirred tank reactor : Reduction of the oxygen carrier

摘要: Abstract This paper deals with the study of methane combustion NiO/NiAl 2 O 4 as oxygen carrier for a better understanding Chemical Looping Combustion. Partial tablets has been investigated in lab scale continuous perfectly auto-stirred tank reactor (CASTR) where reacting gases and steam were diluted argon temperature ranged from 700 °C to 833 °C. Influence water concentrations well are studied. Experimental results show that total oxidized compounds firstly produced, followed by production hydrogen, carbon monoxide coke, covering particles limiting reactions. Increasing or concentration enable reducing coke formation. Analysis reaction products helps defining mechanism ensuring absence any mass heat transfer limitations. A model reduction carrier, based on grainy pellet taking into account diffusion gas species through tablet their reactions at surface each grain is developed. Gas-solid rates calculated using shrinking core catalytic defined according Langmuir–Hinshelwood mechanism. The kinetic parameters redox involved optimized comparison between simulated experimental CASTR. obtained give very good description observed phenomena agreements former published results.