Bifurcation Behaviour During the Hydrogen Production in Two Compatible Configurations of a Novel Circulating Fluidized Bed Membrane Reformer

Abstract

Multiplicity of steady states (static bifurcation behaviour) in a novel circulating fluidized bed (CFB) membrane reformer for the efficient hydrogen production by steam reforming of heptane (model component of heavy hydrocarbons and renewable bio-oils) is investigated. The present paper highlights the practical implications of this phenomenon on the behaviour of this novel reformer with special focusing on hydrogen production. Two configurations are considered. One is with the catalyst regeneration before the gas–solid separation and the other one is with the catalyst regeneration after the gas–solid separation. Multiplicity of the steady states prevails over a number of design and operating parameters with important impact on the reformer performance. The basis of process evaluation is focused on the net hydrogen production. The dependence of the behaviour of this autothermal CFB is shown to be quite complex and defy the simple logic of non-autothermal processes. The unit can be a very efficient hydrogen producer provided its bifurcation behaviour is well understood and correctly exploited.