Intrinsic kinetics. Steam reforming of methane

Various approaches have been applied to establish intrinsic kinetics of steam reforming of hydrocarbons [415], 

The first kinetic studies of the steam reforming reactions were strongly influenced by diffusion restrictions [13] and it was not before the Temkin group [58] studied the reaction on nickel foils in the 1960s that more precise information was achieved [58] [271], 

Early work on the kinetics of the steam reforming of methane [59] was based on the assumption that the methane adsorption was ratedetermining, in agreement with the general assumption of a first-order dependence on methane concentration. Later work by Khomenko et al. [271] avoided the discussion of a rate-determining step instead, the researchers inserted the quasi steady-state approximation in terms of the Temkin identity [75], and the following rate expression was obtained for the temperature range of 470-700°C  

Although attempts have been made to establish kinetics for steam reforming on the basis of a micro-kinetic approach [23] and lately on first principles [264], most work is based on empirical kinetics, which has been sufficient to develop highly sophistieated models for tubular reformers. 

There is a general agreement [58] [379] [516] that the reaction is first-order with respect to methane and that the activation energy is in the range of 100-120 kJ/mol. 

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