Using Petroleum and Biomass-Derived Fuels in Duel-fuel Diesel Engines - Novel Combustion Concepts for Sustainable Energy Development - page 236

Using Petroleum and Biomass-Derived
Fuels in Duel-fuel Diesel Engines

Suresh K. Aggarwal and Xiao Fu

Abstract There is worldwide interest in developing renewable energy sources in a
sustainable manner. Syngas and biogas offer signi

cant potential in this context, as

these fuels offer great flexibility with regard to their production and utilization. This

chapter provides an overview of research dealing with the combustion and emission
characteristics of these fuels, both as stand-alone fuels or by blending with petro-
leum fuels. Conversion methods for producing these fuels from different biomass
sources are also brie

fl

y reviewed. While the syngas composition can vary widely, it
generally has lower heating value, lower density, higher mass diffusivity, higher
fl

fl

flammability limits compared to hydrocarbon fuels.
Moreover, its combustion leads to almost zero soot emission, although NO x
emission may be a concern depending upon its composition and operating tem-
peratures. Similarly, biogas has lower heating value compared to hydrocarbon fuels,
and its ignition and combustion characteristics can vary noticeably depending upon
its composition. While there have been few studies focusing directly on biogas
combustion, there is extensive literature on methane combustion, including ignition,
extinction,

flame speeds, and wider fl

flame speeds, cellular instabilities, and emissions.
Fundamental combustion aspects requiring further research include cellular insta-
bilities,

fl flammability limits, fl

flames, and emission
characteristics. Such efforts would lead to the development of optimized systems
for producing these fuels and provide guidelines for optimizing their composition
for a given set of operating conditions. The use of syngas and biogas in dual-fuel
diesel engines has been a subject of numerous experimental and computational
studies. A general observation is that the engine performance and emission char-
acteristics are signi

fl flame stabilization and blowout behavior, turbulent fl

ed by the presence of gaseous fuel. While the heat
release in a diesel engine generally occurs through a hybrid combustion mode,

cantly modi