HYDROGEN PRODUCTION WITHIN A POLYGENERATION CONCEPT BASED ON DUAL FLUIDIZED BED BIOMASS STEAM GASIFICATION

The dual fluidized bed biomass steam gasification technology generates a high calorific, practically nitrogen free product gas with a volumetric H-2 content of about 40 %. Therefore, this technology could be a promising route for a Polygeneration concept which aims the production of valuable gases (for example H-2), electricity, and heat. In this paper, a lab-scale process chain, based on state of the art unit operations, which processed a tar-rich product gas from a commercial dual fluidized bed biomass steam gasification plant, is investigated regarding H-2 production within a Polygeneration concept. The lab-scale process chain employed a water gas shift unit, two gas scrubbing units, and a pressure swing adsorption unit using activated carbon as adsorbent in order to separate H-2 from the other gas components. During the investigations, a volumetric H-2 concentration of 99.9 % with a specific H-2 production of 30 g kg(-1) biomass was reached. In addition, a valuable off-gas stream with a lower heating value of 7.9 MJ m(-3) was produced. These results show that the dual fluidized bed steam gasification technology is a promising route for a Polygeneration concept which aims the production of H-2, electricity, and district heat.