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Iowa State University researchers have developed a process for upgrading of reactive bio-oil without excess char production or fouling of catalysts.

Bio-oils from pyrolysis operations are complex mixtures of reactive chemicals, and resist techniques conventionally used in the petrochemical refining industry to upgrade crude oil products. The high reactivity of the bio-oil is due to an abundance of unsaturated carbon-carbon bonds as well as a prevalence of carbonyl groups. These tend to react with one another when exposed to high temperatures and active catalysts, resulting in polymerization of the bio-oil compounds into moderate molecular weight polymers that are of little use to the transportation fuel industry.  In this respect, the bio-oils tend to behave in a fashion similar to vegetable oils, which also tend to have some level of unsaturated carbon bonds and carbonyl groups. Hydrogenation of vegetable oils tends to be performed at much lower temperatures and pressures than do the alkene molecules in crude oil.
Iowa State University researchers have developed a process for the successful hydrogenation of the phenolic-based molecules of bio-oil to prepare them for further processing using more standard petrochemical reactions. The reaction conditions used for this upgrading are at low temperatures and pressures.  Mass yields using this process were as high as 99%.

• Enables bio-oil to be used as a drop-in substitute for petrochemical processing

• Milder conditions – lower temperature and pressure reduce operating expenses

Renewable Transportation fuels; renewable chemical processing

1. M.R. Rover et al., “Stabilization of bio-oils using low temperature, low pressure hydrogenation”, Fuel, 153, pp. 224-230, 2015. 

2. U.S. Patent Application 2015/0291892