The dependence in the U.S. on foreign crude oil supplies and increased concerns regarding greenhouse gas emissions has generated considerable interest in research to develop renewable and environmentally friendly liquid hydrocarbon transportation fuels. One of the strategies for achieving this is to produce bio-oil via the direct liquefaction of lignocellulosic biomass (e.g. fast pyrolysis, catalytic fast pyrolysis, hydro-pyrolysis or hydrothermal liquefaction). Each direct liquefaction process generates an aqueous phase with diluted organic compounds at various points in the processing of biomass to fuel.  The aqueous stream may be generated during the direct liquefaction processing itself as in the case of hydrothermal liquefaction or during subsequent upgrading via hydrotreating as in the case of fast pyrolysis.  Depending on the process, the carbon contained in these streams may contain 5-40 percent of the total carbon present in the biomass feed. Converting organic compounds in the aqueous stream into fuel range hydrocarbons has the potential to make the given thermochemical process more economically attractive. Upgrading aqueous phase organic compounds may also reduce or eliminate waste water treatment requirements. In addition, significant H2 savings could be realized in processes where the aqueous phase organic compounds would otherwise be sent to a hydrotreater for upgrading along with the bio-oil.  Initial tests have been performed with model aqueous phase organic compounds over H-ZSM-5 with a Si/Al ratio of 15.  Upgrading tests have also been performed with the same H-ZSM-5 modified with La via ion exchange or through the incipient wetness addition of La2O3 via La(NO3)3. Limited testing also has been performed with water in the condensed phase at 250�C and 1000 psig. The conversion levels of the oxygenated compounds, product selectivity and the effect on the catalyst life time and stability in aqueous environments will be discussed in the presentation.

Upgrading of aqueous phase organic compounds produced by the direct liquefaction of biomass to liquid hydrocarbon fuels

246th National Meeting (2013)

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