(129d) Hydrotreating of Catalytically Upgraded Biomass Pyrolysis Oils

One way to make a liquid hydrocarbon fuel is fast pyrolysis of solid biomass followed by hydrotreating. Catalytic fast pyrolysis followed by hydrotreating is a potentially improved process which may reduce overall process costs by reducing the number of hydrotreating stages required, the amount of hydrogen consumed, and coking of the hydrotreating catalyst.

To assess the potential advantages of this method, three catalytic fast pyrolysis oils—produced with HZSM-5 at biomass-to-catalyst ratios from 0.5 to 2.1 and having oxygen contents from 3 to 18%—and a non-catalytic oil containing 28% oxygen, were hydrotreated in a batch autoclave with CoMo(S) at 330-420°C and 2500 psig total pressure. 

Multiple catalytic-oil and temperature conditions produced products with oxygen contents about 1% by weight.  Hydrogen consumption was less than ½ that of the non-catalytic oil.  GC-MS analysis showed high concentrations of aromatics and hydrogenated aromatics.  Phenols were the main oxygenated compounds detected in the products.  The low-oxygen products and lower hydrogen consumption show that this is a promising alternative.