Hydrogen Production from Catalytic Biomass Pyrolysis

Abstract

An overview is presented on different catalytic routes for producing hydrogen from biomass via pyrolysis processes. Fundamentals of biomass pyrolysis along with general aspects related to the types of processes and catalysts are discussed. Processes that allow hydrogen production in this field have been divided into single-step and multi-step processes. These processes are reviewed in this chapter, showing the state of the art. In both strategies, a hydrogen-rich product gas is obtained which, conveniently conditioned and purified, may serve for various purposes. Catalytic pyrolysis of raw biomass feedstocks aiming at producing hydrogen can be carried out by directly contacting the raw material with a catalyst having a high selectivity towards hydrogen production inside the pyrolysis reactor, in a single-step process. Another possibility for producing hydrogen from biomass follows a strategy based on multiple steps. In the majority of multi-step processes, the biomass raw material is subjected to fast pyrolysis for producing a liquid product, denoted as biomass pyrolysis liquids or bio-oil, and afterwards processing the bio-oil or fractions of it in a catalytic steam reforming process with suitable catalysts. Future trends of catalytic biomass pyrolysis process technologies are described in this chapter.