(4o) Liquid Metal Catalysts for Bio and Synthetic Polymer Pyrolysis

Background and Motivation: Decomposition of bio or synthetic polymers to valuable products – such as lignocellulosic biomass conversion to biofuels, and recycling plastics to its monomers – is still a challenging process. Pyrolysis is known as one of the most feasible and scalable thermal conversion processes. Biomass conversion leads to production of heavily oxygenated oil with wide carbon distributed mixture. Heterogeneous catalysts such as zeolites and alumina were studied to produce deoxygenated narrowly distributed oil. But this class of catalysts suffer from deactivation due to coke deposition on active sites which hinders their commercialization. There is an emerging class of metal catalysts in liquid phase that has been known to address the deactivation from coking. Liquid metals (LMs) have been proven to show separation from coke during reaction due to the inherent density difference between coke and metal in liquid phase thereby promoting a renewed catalyst surface. But there is lack of research into investigating LMs as a robust catalyst alternative for bio and synthetic polymer pyrolysis process.

Research Interests: Interest 1: Establishing the evidence of catalysis using LM systems for cellulose, lignin (major biomass model compound) and polycarbonate (example synthetic polymer) pyrolysis is the first important step. Indium, tin and bismuth are chosen as candidate catalysts for low melting LM systems based on their melting point < onset of pyrolysis. Deconvolution of the pyro-oil product spectrum using GC-MS, and elemental and FTIR analyses of char together provide a sound proof of catalysis for each LM catalyzed pyrolysis case. Interest 2: The second step will focus on proving the robustness of LM catalytic systems against deactivation through coking. Using a semi-batch reactor setup raw material will be fed into the system catalyzed by the same LM catalyst bed. Deriving a bio-oil product distribution more like the non-catalyzed pyrolysis will act as the baseline for comparison of the catalytic effect. Interest 3: Finally, we are interested in gaining a broader insight about the greenhouse gas (GHG) emissions associated with the biomass pyrolysis via LMs for the purpose of diesel production and compare it with conventional non-catalytic pyrolysis process using life cycle assessment (LCA).