(629w) High Throughput Screening of Catalytic Materials for JP-8 Fuel Reformation

Within the past decade, the high-throughput approach has
become widespread in the field of catalysis (1-3).  In this work, this methodology is applied for the
discovery and optimization of catalytic materials for reformation of military
jet fuel (JP-8) to lighter hydrocarbons.  JP-8 is the single battlefield fuel
of NATO and the U.S. Military.  These organizations have a critical need for
converting their preferred fuel source into a flexible and readily available
power supply for portable applications, such as solid oxide fuel cells and
liquefied petroleum gas.  The objective of this work is to use a
high-throughput screening approach to discover and optimize novel reforming
catalyst formulations that will enable reforming technology to convert readily
available hydrocarbon-based fuels, such as JP-8, directly to a lighter
hydrocarbon feed suitable for portable fuel cell applications.

An existing high-throughput reactor system (4) was modified for the JP-8 reforming
studies.  The reactor system consists of 16 separate stainless steel reactor
tubes that are loaded with individual powder catalyst samples, typically
between 150 mg and 750 mg, and tested under realistic conditions.  The
high-throughput reactor system operates at ambient pressure with a temperature
range between room temperature and 1100 K and space velocities between 3,500
(mL/hr * g_cat) and 200,000 (mL/hr * g_cat).  Liquid JP-8
is dosed into a heated mixer with high internal evaporative surface area, where
it is vaporized and combined with carrier gas to form the reactant gas feed.  The
reactor effluent streams from each of the individual reactors remain in
separate channels throughout the analysis process to prevent the mixing of
reaction products from occurring.  The reactor effluent passes through a
parallel condenser system to remove any unreacted JP-8 before proceeding for
analysis.

The gaseous product stream then enters a rapid-scan Fourier
transform infrared (FTIR) spectroscopic imaging system.  This system enables
chemically-sensitive, parallel screening of all 16 gas-phase reactor product
distributions through a gas phase array (GPA), incorporating a 128x128 focal
plane array (FPA) detector as the infrared (IR) detecting element.  In
addition, a gas chromatography-mass spectrometry (GC-MS) system is incorporated
via a computer controlled 16-way switching valve and allows for further
quantitative analysis of the product composition of the effluent streams.  The
GC-MS is capable of identifying and differentiating between specific
hydrocarbon molecules and was calibrated to provide compositional information
for each desired product.

Catalysts are analyzed for their desired properties, such as
conversion, selectivity, sulfur tolerance, and coking resistance.  Because JP-8
may contain up to 3,000 ppmw sulfur, sulfur-tolerant reforming catalysts that
can withstand coking and demonstrate long-term activity and stability are
required.  Catalysts that can produce a well-defined sulfur-containing product
distribution can be optimized using existing clean coal technology for removal
of sulfur compounds.  By applying a high throughput methodology to this
process, a large number of materials are screened, including several monometallic
transition metals, such as Rh, Pd, Pt, Ru, and Ir, as well as bimetallic
combinations involving active metals.  In addition,
several oxide support materials, including Al₂O₃, SiO₂,
CeO₂, ZrO₂, MoO₂, and Nb₂O₅,
were synthesized and tested.  The high throughput methodology allows for a
comprehensive search of the parameter space affecting catalyst performance,
including catalyst composition, support materials, operating conditions, as
well as pre-treatment options.

1.            R. J. Hendershot, C. M. Snively, J. Lauterbach,
High-throughput catalytic science. Chemistry-A European Journal 11,
806 (Jan 21, 2005).

2.            W. F. Maier, K. Stowe, S. Sieg, Combinatorial and
high-throughput materials science. Angewandte Chemie-International Edition
46, 6016 (2007).

3.            I. Takeuchi, J. Lauterbach, M. Fasolka, in Materials
Today. (2005), vol. 8, pp. 18-26.

4.            R. J. Hendershot et al., A novel reactor
system for high throughput catalyst testing under realistic conditions. Applied
Catalysis a-General 254, 107 (Nov 10, 2003).