Catalytic conversion of a biomass-derived oil using various catalysts

The upgrading of a biomass-derived oil (obtained from rapid thermal pyrolysis of maple wood) was carried out in a fixed-bed micro-reactor at atmospheric pressure at temperatures and space velocities (WHSV) in the range 330-410 degreesC and 1.8-7.2 h(-1), respectively over a variety of catalysts namely, HZSM-5, HY, molecular sieves (SAPO-11), silica-alumina, and mixtures of HZSM-5 + silica-alumina. The results showed that HZSM-5 catalyst gave the largest hydrocarbon fraction in the product (mostly aromatics in the gasoline boiling range) amongst all the catalysts studied. On the other hand, HY catalysts gave a high selectivity for kerosene range hydrocarbons. Product from SAPO-11 catalyst consisted of a mixture of aliphatic and aromatic hydrocarbons whereas those from silica-alumina consisted mostly of aliphatic hydrocarbons. Results further showed that the product slate was dramatically altered by changing the characteristics (i.e., functionality) of the catalyst. For example, with a mixture of 20 wt % HZSM-5 and 80 wt % silica-alumina catalyst, the product composition dramatically changed to almost all aliphatic hydrocarbons (essentially iso-octane which has an octane number of 100). An attempt has been made to present possible reaction pathways for bio-oil upgrading over the various groups of catalysts used.