Applied Engineering in Agriculture Vol. 26(1): 137‐146 E 2010 American Society of Agricultural and Biological Engineers ISSN 0883-8542 137 STEAM PYROLYSIS AND CATALYTIC STEAM REFORMING OF BIOMASS FOR HYDROGEN AND BIOCHAR PRODUCTION K. C. Das, K. Singh, R. Adolphson, B. Hawkins, R. Oglesby, D. Lakly, D. Day ABSTRACT. Steam pyrolysis of woody biomass followed by catalytic steam reforming of pyrolysis vapors for renewable hydrogen production has been the center of attraction for many bench scale studies in recent years; however, sufficient pre‐commercial testing has not been conducted or reported in literature. In addition, it is known that the cost of renewable hydrogen production could be reduced by co‐production of biochar, a solid pyrolysis product used in carbon sequestration and soil enhancement for agriculture. This article presents results of a pilot‐scale study for renewable hydrogen production from commercially available pine and peanut hull pellet biomass. In addition, the effect of temperature on biochar yield, pH, and its nutrient properties was also documented in bench‐scale studies using pine chip, pine bark, hardwood, and peanut hull pellet biomass. Bench‐scale test results showed that biochar yield reduced with increasing temperature of pyrolysis. There was no observable impact of pyrolysis temperature on biochar pH for the temperatures tested in this study. Woody biomass had significantly lower nutrients (both total and plant‐available forms) than peanut hull pellets. In the case of pine bark, pine chips, and hardwood, there appears to be an increase in plant‐available potassium (K) (as a percentage of total K) with an increase in pyrolysis temperature. Pilot‐scale test results provided a hydrogen yield of 0.07‐kg/kg biomass or equivalent to 42.9% of theoretical stoichiometric yield for pine pellet biomass; however, it was 0.04‐kg/kg biomass or equivalent to 21.42% of theoretical stoichiometric yield for peanut hull pellet biomass. Keywords. Hydrogen, Steam pyrolysis, Steam reforming, Biochar. he development of high‐efficiency energy systems such as fuel cells and their application in the transportation sector has generated significant interest in the use of hydrogen as a fuel. Traditionally, hydrogen is produced by catalytic steam reforming of natural gas and oil derived naphtha, and partial oxidation of heavy oils. This process releases comparable amounts of carbon dioxide into the atmosphere as those formed from combustion of those fuels. Renewable hydrogen production from biomass is therefore an attractive alternative due to its low carbon footprint. Scientists have explored several technologies to produce hydrogen from biomass such as biomass catalytic pyrolysis (García et al., 1998; García et al., 2001; Dermirbaş, 2002; Chen et al., 2003) biomass Submitted for review in May 2009 as manuscript number SE 8025; approved for publication by the Structures & Environment Division of ASABE in October 2009. The authors are Keshav C. Das, ASABE Member Engineer, Associate Professor, Department of Biological and Agricultural Engineering, University of Georgia, Driftmier Engineering Center, Athens, Georgia; Kaushlendra Singh, ASABE Member Engineer, Assistant Professor, Division of Forestry and Natural Resources, West Virginia University, Morgantown, West Virginia; Ryan Adolphson, Director of Engineering Outreach Service, Department of Biological and Agricultural Engineering, University of Georgia, Driftmier Engineering Center, Athens, Georgia; Bob Hawkins, Project Manager, Head Research Chemist, Eprida Inc., Athens, Georgia; Rebecca Oglesby, Project Manager, Eprida Inc., Athens, Georgia; Donald Lakly, Research Technician, Department of Biological and Agricultural Engineering, University of Georgia, Driftmier Engineering Center, Athens, Georgia; and Danny Day, Founder, President, Eprida Inc., Athens, Georgia. Corresponding author: K. C. Das, Department of Biological and Agricultural Engineering, Driftmier Engineering Center, Agriculture Drive, Athens, GA 30602; phone: 706‐542‐8842; fax: 706‐542‐8806; e‐mail: kdas@engr.uga.edu. steam gasification (García et al., 1999; Antal et al., 2000; Rapagnà et al., 2002), and steam reforming of liquids derived from biomass such as bio‐oil, vegetable oils, or bioethanol (Wang et al., 1997; Czernik et al., 2002; Fatsikostas et al., 2002). Cortright et al. (2002) not only derived the reaction pathways of these conversions, but also demonstrated that hydrogen can be produced from sugars and alcohols at temperatures around 500K in a single‐reactor aqueous phase reforming process using a platinum‐based catalyst. Thermo‐chemical processes involving slow pyrolysis followed by catalytic steam reforming has been explored for co‐production of biochar and hydrogen (Cortright et al., 2002; Evans et al., 2002; Galgámez et al., 2005). Evans et al. (2002) demonstrated that the above process can produce 76.0 kg of hydrogen and 350 kg of biochar from one ton of dry biomass, which is estimated to be about 67.8% of the stoichiometric hydrogen yield based on an approximate biomass composition. Although renewable biomass is an attractive alternative to fossil‐fuel‐based hydrogen production because of nearly zero net carbon dioxide impact on environment, producing hydrogen from biomass cannot compete with the well‐developed technology for steam reforming of natural gas due to low hydrogen yield from biomass (6.0% to 6.5%) unless a pyrolysis‐based biorefinery approach with co‐products is used (Czernik et al., 2000). Pyrolysis is a process of thermal degradation of biomass in the absence of oxygen. The products of pyrolysis are biochar (solid black residue), hydrocarbon bio‐oil (condensable hydrocarbons), and permanent gases. Generally, pyrolysis of biomass is done in an anoxic atmosphere; however, presence of steam during the pyrolysis favors the formations of liquid products. In addition, solid T