Using Petroleum and Biomass-Derived Fuels in Duel-fuel Diesel Engines - Novel Combustion Concepts for Sustainable Energy Development - page 240

chemical formula of CH 1.9 O 0.7 . The typical heating value of bio-oil is about 17 MJ/
kg, which is about 40 45 % of that of hydrocarbon fuels. The physical properties of

bio-oils are discussed by Czernik and Bridgwater ( 2004 ), while Bridgwater ( 2012 )
and Mohan et al. ( 2006 ) provide reviews on fast pyrolysis and the properties of bio-
oils generated from this process. Bio-oil can be utilized in several different ways to
produce energy, fuels, and chemicals. It has been used directly as fuels in stationary
applications, especially for electricity generation. A more sustainable and value-
added approach is based on a bio-re

-

nery,
for producing energy, conventional fuels, such as syngas and Fischer-Tropsch (FT)
fuels, and chemicals. This concept is particularly attractive for biomass because of
its chemical heterogeneity and regional variability.
Biomass gasi

nery concept, similar to a petroleum re

cation involves pyrolysis and partial oxidation in a well-controlled
oxidizing environment. It is deemed as the most promising technology for pro-
ducing renewable and carbon-free energy, as it provides great

flexibility with regard
to feedstock and the fuels produced. In recent years, numerous studies have
reported on the different types of reactors used in gasi

fl

cation, and the various
gaseous and liquid fuels produced. Wang et al. ( 2008b ) and Gill et al. ( 2011 )
provide reviews of these studies. In general, the gasi

cation process converts low-
value biomass to a gaseous mixture containing syngas and varying amounts of CH 4
and CO 2 . It can also produce hydrocarbons by using lower operating temperatures.
The syngas composition, or the relative amounts of CO and H 2 in the syngas, can
be varied by using air and steam as the gasi cation agent (Rapagna et al. 2000 ). In

addition, CO 2 can be used in the presence of a catalyst, such as Ni/Al, to increase
the H 2 and CO content (Ollero et al. 2003 ).
Syngas offers signi flexibility with regard to its utilization. Syngas from

coal, known as town gas, was extensively used for lighting and heating during the
nineteenth and early part of twentieth centuries. In recent years, there has been
renewed interest in the utilization of coal-based syngas for stationary power gen-
eration through integrated gasi

cant fl

cation combined cycle (IGCC) facility (Rodrigues
et al. 2003 ). In addition, it can be used to provide H 2 (Watanabe et al. 2002 )or
synthesized to produce chemicals and liquid fuels, such as F-T fuels (Tijmensen
et al. 2002 ). The use of syngas in fuel cells, such as solid oxide fuel cells, through
the reforming of hydrocarbons and other routes is also being explored (Kee et al.
2005 , 2008 ). Figure 4 in Gill et al. ( 2011 ) summarizes the various routes for the
utilization of syngas, including the production of F-T and other transportation fuels.
Gill et al. ( 2011 ) provide an overview of technologies, including Biomass-to-Liquid
(BTL) and Coal-to-Liquid (CTL) Gas-to-Liquid (GTL) processes, for producing
various fuels through gasi

cation and F-T processes. It should be noted, however,
that some of these routes may be more energy intensive, and their cost effectiveness
and environmental bene ts need to be examined, as it may be more economical to

use syngas directly as fuel or for electricity generation.
Biogas or land

ll gas (LFG) is typically produced from anaerobic decomposition
of organic matter (Gunaseelan 1997 ). It can also be produced through pyrolysis and
gasi

cation processes. Primary sources include biomass, green waste, plant material,
manure, sewage, municipal waste, and energy crops. While its composition can vary