(133e) Ni/Al2O3 Reforming Catalyst Deactivation From Actual Biomass-Derived Syngas Clean-up & Conditioning

Attrition resistant Ni/Al2O3 steam reforming catalysts developed for the clean-up and conditioning of hardwood-derived synthesis gas (syngas) were tested at the pilot scale (~60 kg catalyst). Oak pellets were indirectly steam gasified in a two-stage process that formed tars and polynuclear aromatic hydrocarbons (PAH) in concentrations of approximately 2 vol%. Raw syngas compositions generated from this study were used to develop a model syngas stream and appropriate baseline operating conditions for use in a bench scale system (~500 mg catalyst). This system, designed for rapid throughput catalyst testing, was used to identify possible modes of catalyst deactivation by independently varying operating parameters such as catalyst pretreatment, reforming time, regeneration time, reduction time and H2S concentration. We found that with controlled bench scale conditions, the catalyst is fully regenerable after sequential cycles of reforming and reactivation . In addition to measuring deactivation and regeneration extent with conditions designed to fully challenge the catalyst, possible causes for deactivation were examined using several bulk and surface characterization methods including BET surface area analysis, mercury pore size measurements, and ICP bulk concentration analysis. Results from these studies are discussed with regeneration recommendations extended to pilot scale reforming operation.