WEST LAFAYETTE, Ind. — Researchers at Purdue University have
successfully tested the conversion of large particles of pinewood char in a
gasification process, a step necessary for the mass production of synthetic
liquid fuel from recalcitrant biomass.
The results, which will be published in the March edition of
the journal Fuel , stemmed
from a series of experiments using a new facility at Purdue’s Maurice J. Zucrow
Laboratories aimed at learning precisely how biomass is broken down in reactors
called gasifiers as part of a project to strengthen the scientific foundations
of the synthetic fuel economy.
“The results of the study show that the apparent
gasification rate parameters for relatively large particles of practical
relevance are comparable to those obtained from laboratory studies with much
smaller particles,” said Purdue mechanical engineering doctoral student
Indraneel Sircar, a graduate assistant at Zucrow Labs and paper co-author. “On a
larger scale, this research is a small part in the goal of creating a more
sustainable synthetic fuel economy.”
Synthetic fuels currently are being blended with petroleum
fuels for performance improvement in automobile and aircraft applications and
also are used in equipment trials in commercial aircraft. New techniques,
however, are needed to reduce the cost and improve the efficiency of making the
In the Purdue study, the researchers measured the rate
parameters for pinewood char gasification with carbon dioxide, using large
particles in relation to practical gasifiers.
The char was prepared by inert heating of a large quantity
of low-ash pinewood sawdust in an electrical furnace to a temperature of 1,100
degrees Kelvin. The low-ash pinewood char was selected to minimize the catalytic
effects of ash on mass-loss rates.
The researchers said char gasification for carbon dioxide
recycling was used because it has been studied less than char gasification in
other environments and has the potential to reduce greenhouse gas emissions by
recycling carbon dioxide from stationary power plant exhaust streams.
They relied on independent measurements from gravimetric
analyses and product gas composition analyses to determine char mass-loss rates
and conducted detailed uncertainty analyses of both methods and reported
uncertainties in kinetic rate parameters. They also investigated the char
structure development with reaction progress and its implication on mass-loss
Joining Sircar as authors of the paper are Purdue mechanical
engineering doctoral students Anup Sane and Weichao Wang and Jay Gore, the
Reilly University Chair Professor of Combustion Engineering.
“This study, specifically on the widely available pinewood,
moves us a step closer toward mass producing this as a synthetic fuel for uses
by the U.S. air transportation system, thereby reducing our reliance on
petroleum oil,” Gore said.
Purdue researchers also are using the facility at Zucrow
Labs to learn how coal and biomass “gasify” under high pressure in order to
improve the efficiency of the gasification process. Students are working on
doctoral theses on the system’s mechanical design, optical diagnostics and
approaches for integrating aerospace-related technologies.
In addition, they hope to determine how to generate less
carbon dioxide than conventional synthetic-fuel processing methods while
increasing the yield of liquid fuel by adding hydrogen into the
coal-and-biomass-processing reactor, a technique pioneered by Rakesh Agrawal,
Purdue’s Winthrop E. Stone Distinguished Professor of Chemical
Findings published in 2009 showed that carbon dioxide might
be reduced by 40 percent using the technique.
The research is part of a larger effort to develop a system
for generating large quantities of synthetic fuel from agricultural wastes,
other biomass or coal that would be turned into a gas and then converted into a
Gore and Robert Lucht, the Ralph and Bettye Bailey Professor
of Combustion in Mechanical Engineering at Purdue, are working with faculty from
Purdue’s schools of Aeronautics and Astronautics and Chemical Engineering and
other Purdue faculty members.
The work is funded by the U.S. Air Force Office of
Scientific Research and has been done in conjunction with the Purdue Energy
Center, located in Discovery Park.