The production of commercially viable bio-fuels from pyrolysis bio-oils requires improvement in processing technology, particularly with respect to upgraded product stability and catalyst lifetime. Catalyst effectiveness is the limiting factor. Based on studies performed through a previous EAGER award, Professors Dorin Boldor and Daniel Hayes at the Louisiana State University believe they have an approach to improve the situation. By utilizing direct heating of only the metal particle supported nanoscale catalysts, bio-organic polymers and precursors are rapidly broken down and converted into higher quality oil with extremely high yield compared to state-of-the-art pyrolysis techniques. In contrast to current generation reactor design where the reactor sidewall is heated and the catalyst acts as a heat sink, in this system the oscillating magnetic field from RF induction coils or microwave sources induce eddy currents on the surface of the supported catalyst resulting in induction heating where the metallic core of the catalyst acts as a heat source for pyrolysis and the catalyst works most efficiently for product upgrading. The single step process is expected to be more energy efficient and provide a greater yield of high value product while extending the life of catalyst. Additionally, this process can efficiently use a variety of organic polymers as feedstock. Materials such as recycled plastic bottles, wood chips or agricultural waste can be turned into high value bio-oil.
In order to be functionally useful, pyrolysis oil needs to be catalytically upgraded and stabilized, usually in reactors operating at high temperature and pressure. During upgrading, unstable molecules have a tendency to re-polymerize into higher-molecular weight compounds, which, coupled with the residual phosphorus and sulfur (native to the biomass), tend to inhibit the catalyst active sites, requiring frequent maintenance and reducing catalyst lifetime. Inhibition of catalytic sites is thermodynamically favored in conventional reactors, where the heat is carried by the bio-oil vapors, with the catalyst bed acting as a heat sink. Thus, molecular migration is favored to proceed toward the catalyst surface, and is impeded from moving away from the surface. From the perspective of controlling (i.e. accelerating) reactions and optimizing the process while prolonging the catalyst life, it is preferable to rationally design a catalyst-pyrolysis process that is able to generate thermodynamically favorable molecular transport where the molecules on the product side migrate away from the reaction surface. In order to achieve this goal, it is desirable to reverse the thermal flux from the carrier reactants in vapor phase, using the catalyst surface, or logically its support, as a heat source. The proposed approach includes a study of biomass pyrolysis at various temperatures, in conjunction with upgrading in electromagnetic fields using surface supported nanoscale metallic and zeolite catalysts. The results and process performance will be evaluated by quantitative and qualitative measurements of the produced bio-oil, char, and non-condensable gases from different biomass; by evaluating the catalyst performance and quality after repeated experiments; and by providing data for a techno-economic and engineering analysis in order to determine the feasibility of scaling up the process.
