Environmental Engineering Reference
In-Depth Information
of these biofuels is to ensure that their environmental impact is minimal and that
their performance in practical combustion devices is positive.
Although the performance of practical devices such as internal combustion
engines and gas turbines running on these fuels has been extensively investigated in
the past by several researchers, a fundamental understanding of the science of
thermochemical processes and pollutant formation during the combustion of bio-
fuels and their blends, particularly the coupling effects of fuel chemistry and
combustion conditions, is lacking. In many situations, these fuels burn in partially
premixed
gurations.
This article begins with an overview of the research program on combustion of
renewable fuels at the Combustion and Flame Dynamics Laboratory of the University
of Oklahoma, USA, and is followed by the speci
fl
ame con
c details of the investigations on
vaporized biodiesel fuel combustion. Results include thermochemical characteristics,
such as temperature and concentration
fields, radiation emission and extinction
phenomena, and formation of environmental pollutants such as NO and CO.
2 Background and Motivation
With a motivation to understand the basic thermochemical processes, combustion
characteristics, and environmental impact of increasing biofuel use in recent years,
a comprehensive research program was initiated in the Combustion and Flame
Dynamics Laboratory of the University of Oklahoma, USA. This program was
designed with a systematic approach consisting of several phases. The initial phase
consisted of simple laminar
flames of vapor-phase fuels (biofuels as well as
petroleum fuels and their blends) whose characteristics depended mostly on the
thermochemical properties of reactants (Love et al.
2009a
; Singh et al.
2013
). Since
air was used as the oxidizer in all the studies, the
fl
flame characteristics depended on
the fuel properties. The second phase consisted of turbulent
fl
fl
flames of the same
vapor-phase fuels in which the effects of
fluid dynamics were introduced (Dhamale
et al.
2011
). The third phase consisted of liquid spray
fl
flames in which the additional
effects of atomization and phase change were added (Erazo et al.
2010
). The fourth
phase included testing these fuels in intermittent ignition and combustion devices
such as internal combustion engines and continuous combustion devices such as
gas turbine engines and furnaces (Habib et al.
2010
; Sequera et al.
2011
; Morton
et al.
2013
). The
fl
fifth phase examined the application in novel combustion burners
such as porous media-supported
fl
flames (Barajas et al.
2012
). The sixth phase
consisted of
fl
flame extinction characteristics in counter
fl
ow burner con
gurations
(Grisanti et al.
2013
). The seventh phase dealt with biofuel pool
fires, with a focus
on
fire safety and handling characteristics of biofuels (Tran et al.
2014
). Both
performance characteristics (in-
ame concentration, radia-
tion, and exhaust emissions of pollutant species such as NO
x
, CO, and soot in-
fl
ame temperature, in-
fl
fl
ame
con
c fuel consumption, and emissions (in
the studies with practical devices) were recorded. By comparing and contrasting
gurations), output power/thrust, speci
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