Pure hydrogen from biogas: Intensified methane dry reforming in a two-zone fluidized bed reactor using permselective membranes

Abstract

Methane dry reforming of biogas can be a sustainable source of hydrogen but the development of this technology is hindered by limitations such as endothermicity and catalyst deactivation by coke. A two zone fluidized bed reactor coupling permselective Pd/Ag membranes counteracts them and allows to intensify the process obtaining a stable pure hydrogen production. Here we report the effect of operation variables (i.e., temperature, total bed height, nature and partial pressure of regenerative agent, relative height of the regeneration and reaction zones, and use of an activation period) on the yield to hydrogen and stability of the process. Hydrogen over-yields, compared with the conventional fluidized bed reactor, in the range of +200% to +100% were obtained for the entire interval of temperatures 475–575 °C whilst maintaining stable operation by continuous catalyst regeneration. Around 70% of it was pure hydrogen coming from the permeate side of the membranes. The proposed reactor configuration greatly increases both methane conversion and selectivity to hydrogen (expressed as H2/CO ratio), not only in relation to our own conventional reactor findings but also regarding other published results.