Design studies of a pure hydrogen production plant from biogas

Abstract

The present paper focus in design studies of a process for pure hydrogen production at decentralized scale. 9000 Nm3/h biogas are proposed as feedstock to the process. The plant includes a biogas-to-biomethane purification unit, a convective reformer equipped with bayonet-type tubes, a Pd-based membrane reactor profiting simultaneous hydrogen extraction and extra hydrogen production via water-gas shift, a combustion chamber and auxiliary units. Three optimization scenarios were considered where the hydrogen production is maximized and reformer and membrane reactors areas are minimized using different weights. All designs are fully thermally integrated aiming self-sustainability in terms of energy. To these ends, the retentate of the membrane reactor and the permeate of the biogas purification unit are both used as fuel to the combustion chamber. Results show the feasibility of operation with an overall thermal efficiency for the process of ca. 77.0–77.5% (based on LHV), comparable with values reported for processes of similar scale.