(773a) Autothermal Staged Reactors for Biomass Upgrading
We demonstrate an autothermal single-pipe staged reactor system that combines multiple catalytic functions for biomass upgrading reactions. The reactants are fed to an upstream noble metal catalyst consisting of Rh or Pt on 1.3 mm ID α-Al2O3 spheres, forming catalytic partial oxidation (CPO) products. These products react further over a downstream HZSM-5 zeolite catalyst composed of crushed pellets that are 0.7 mm ID. The energy released from upstream CPO drives the downstream endothermic zeolite reactions. The staged reactor setup has been used to produce high yields of ethylene and dimethyl ether from common biomass surrogates such as ethanol and methanol. We also demonstrate a side-feed configuration with methane as a sacrificial fuel and the alcohol introduced as a feed between the noble metal stage and zeolite stage. In this configuration, the alcohol is preserved for dehydration reactions on the zeolite stage rather than be consumed by CPO in the noble metal stage. The staged reactor configuration has also been used to form gasoline-range compounds from decane, a non-oxygenated surrogate for biodiesel, by partial oxidation and partial depolymerization in the noble metal stage. The hydrocarbon products react further over a bifunctional Pt/HBEA zeolite with hydrogen produced by upstream catalytic partial oxidation. The bifunctional zeolite catalyzes hydrocracking and hydroisomerization reactions to form branched gasoline-range hydrocarbons. A staged reactor configuration with multiple catalysts can greatly expand the chemical functionality of autothermal reactors for biomass upgrading.