(585bu) Kinetics of the Water Gas Shift over a Cu-Based Catalyst for Pyrolysis Vapor Upgrading

Kinetics of the Water Gas Shift over a
Cu-based Catalyst for Pyrolysis Vapor Upgrading

Ross Houston^a, Nicole Labbé^b and
Nourredine Abdoulmoumine^a,b

^aBiosystems Engineering and Soil Science
Department, University of Tennessee, Knoxville, TN 37996

^bCenter for Renewable Carbon, University of
Tennessee, Knoxville, TN 37996

Abstract

            Biomass pyrolysis vapors have
limited applications due chiefly to its high oxygen content. While many
approaches are explored to reduce oxygen content in these vapors, hydrodeoxygenation
has emerged as the most effective method to minimize carbon loss by removing
oxygen as water. The goal of this study is to investigate hydrogen production
for deoxygenation via the water gas shift reaction using carbon monoxide (CO),
one of the major non-condensable gases of pyrolysis and steam, a by-product of hydrodeoxygenation.

            Prior to the catalytic
experiments, the Cu-based catalyst was characterized by physisorption for
surface area and pore volume and elemental composition. Water gas shift
experiments were carried out over the size reduced catalyst (0.425-0.600 mm) on
a bench-scale catalytic packed bed reactor (PBR) in a CO-lean environment (70
vol. % water, 20 vol. % He, and 10 vol. % CO). The experimental temperatures
varied from 150°C to 400°C at 50°C interval and three different weight hourly
space velocities (1221, 2036 and 6107 cm³/g-min). A full-factorial
experiment with three replicates was developed, and the conversion of CO was
analyzed using a gas chromatograph (GC) equipped with a thermal conductive
detector (TCD).

            The surface area and pore
volume of the catalyst were 62.174 m²/g and 0.218 cm³/g,
respectively and its elemental composition is as follows: 50% copper oxide, 25%
zinc oxide, <25% aluminum oxide, and a balance of graphite. Preliminary results
show that CO conversion increases with increasing temperature and catalyst
weight to maximum CO conversion of 85-90 % at 300°C and 350°C.