Autothermal Reforming of Renewable Fuels

The conversion of biomass into energy and chemicals is a major research and technology challenge of this century, comparable to petroleum processing in the last century. Recently we have successfully transformed both volatile liquids and nonvolatile liquids and solids into syngas with no carbon formation in autothermal catalytic reactors with residence times of ~10 milliseconds. In the proposed research program we explore the mechanisms of these processes and their extensions to other biomass sources and applications by examining different feeds, catalysts, flow conditions, and steam addition to maximize production of either syngas or chemicals. We will systematically study the catalytic partial oxidation in millisecond autothermal reactors of solid biomass and the liquid products formed by pyrolysis of solid biomass. We will examine alcohols, polyols, esters, solid carbohydrates, and lignocellulose to try to maximize formation of either hydrogen and syngas or olefins and oxygenated chemicals. We will explore molecules and mixtures of practical interest as well as surrogate molecules that contain the functional groups of biofuels but are simpler to analyze and interpret. We will examine spatial profiles within the catalyst and transient and periodic operation of these reactors at pressures up to 10 atm to obtain data from which to explore more detailed mechanistic models and optimize performance to produce a specific desired product. New experiments will examine the conversion of syngas into biofuels such as methanol and dimethyl ether to explore the entire process of producing biofuels from biomass in small distributed systems. Experiments and modeling will be integrated to probe and understand detailed reaction kinetics and the processes by which solid biomass particles are transformed into syngas and chemicals by reactive flash volatilization

The engineering of chemical reactions

xvi, 536 p. : ill. ; 25 cm

Abstract Density-Functional-Theory Modeling of Cyclohexane Partial Oxidation in Millisecond Single-Gauze Reactors*

Cyclohexane oxidation over a Pt–10%Rh single-gauze catalyst can produce ~85% selectivity to oxygenates and olefins at 25 % cyclohexane conversion and 100% oxygen conversion, with cyclohexene and 5-hexenal as the dominant products and cyclohexanone a minor product. Density Functional Theory using the B3LYP/6-31+G(d) method for geometry optimizations and thermodynamic analyses has been employed for the prediction of reaction enthalpies and rate-constant parameters for the partial oxidation of cyclohexane in single-gauze chemical reactors. The model examined includes 28 species and 44 irreversible (22 reversible) gas-phase reactions. The energetics of major gas-phase reaction channels are probed by locating stable reactants, products, and transition-state intermediates. Understanding the favored reaction pathways suggests ways to adjust reactor operation for desired product distributions. Detailed numerical simulations of the surface-assisted gas-phase process will allow the investigation of experiments which are costly or potentially dangerous to carry out