158
Water for Energy and Fuel Production
glycerol, ethylene glycol, and methanol (with carbon/oxygen [C/O] ratio close to one)
to produce hydrogen, syngas, lower alkanes (C 1 –C 6 ), and various monofunctional
groups. The monofunctional groups can be subsequently converted to a variety of
liquid fuels such as gasoline, diesel, and jet fuels (or their additives) with another
set of catalysts. This overall process is called “APR and its derivative technologies”
or bioforming process [1]. The selective APR reactions generally occur in the
temperature range of 215°C–265°C. The upgrading of monofunctional groups
generally requires a somewhat higher temperature. The nature and quality of products strongly depend on the feedstock and the nature of the catalyst, support, and
promoter along with other operating conditions such as temperature, pressure, acidity of slurry and catalyst, and solid concentration in the feed slurry. Unlike the
process of hydrothermal conversion described in Chapter 5, this is a very selective
catalytic process targeted to only certain types of compounds, producing targeted
fuels and chemicals [1–6].
6.2 aQUeOUs-Phase reFOrminG
The pioneering work carried out by Dumesic et al. [1–6] showed that carbohydrates
such as sugars (e.g., glucose) and polyols such as methanol, ethylene glycol, glycerol,
and sorbitol can be efficiently converted to hydrogen and carbon dioxide at 500 K
by reforming under aqueous conditions. The process can be applied to all carbohydrates found in wastewater from biomass processing of cheese whey, beer brewery,
sugar processing as well carbohydrate streams from agricultural products, such as
corn and sugar beets and hemicellulose from any biomass [4,15]. Typical feedstock
that can be used for APR and bioforming process are listed in Table 6.1 [4,15]. The
secondary feedstock mentioned in the table are first converted to primary feedstock
(by hydrolysis and/or hydrogenation processes depending on the feedstock), before
using them for APR process. The produced hydrogen can be used to hydrogenate
many components of lignocellulosic biomass to produce glycols and other polyols,
thus enlarging the feedstock possibilities for APR. The hydrogen can also be used to
produce ammonia and fertilizer, an additive to gasification products to produce liquid fuels via FT synthesis and fuel source for polymer electrolyte membrane (PEM)
fuel cells.
Besides hydrogen, APR can also produce syngas (CO and H 2 ), alkanes, and monofunctional groups depending on the nature of the catalyst and the operating conditions. As will be discussed later, the production of hydrogen and syngas requires the
breakage of C–C bonds within oxygenated compounds, whereas the production of
alkanes and monofunctional groups requires the breakage of C–O bonds within the
oxygenated compounds. With most feedstock examined so far, the alkane production is limited to six carbon atoms. More feedstock, catalysts, and reactor designs are
needed to produce C 8 –C 15 alkanes from the biomass-derived reactants. The alkanes
and monofunctional groups can be further upgraded catalytically by creating new
C–C bondages (through condensation reactions) to produce higher alkanes and liquid fuels. The light fuel additives such as pentane and hexane have limited values
due to their high volatility. Various reaction paths that can be produced by APR
process are schematically illustrated in Figure 6.1 [4].
Water for Energy and Fuel Production
glycerol, ethylene glycol, and methanol (with carbon/oxygen [C/O] ratio close to one)
to produce hydrogen, syngas, lower alkanes (C 1 –C 6 ), and various monofunctional
groups. The monofunctional groups can be subsequently converted to a variety of
liquid fuels such as gasoline, diesel, and jet fuels (or their additives) with another
set of catalysts. This overall process is called “APR and its derivative technologies”
or bioforming process [1]. The selective APR reactions generally occur in the
temperature range of 215°C–265°C. The upgrading of monofunctional groups
generally requires a somewhat higher temperature. The nature and quality of products strongly depend on the feedstock and the nature of the catalyst, support, and
promoter along with other operating conditions such as temperature, pressure, acidity of slurry and catalyst, and solid concentration in the feed slurry. Unlike the
process of hydrothermal conversion described in Chapter 5, this is a very selective
catalytic process targeted to only certain types of compounds, producing targeted
fuels and chemicals [1–6].
6.2 aQUeOUs-Phase reFOrminG
The pioneering work carried out by Dumesic et al. [1–6] showed that carbohydrates
such as sugars (e.g., glucose) and polyols such as methanol, ethylene glycol, glycerol,
and sorbitol can be efficiently converted to hydrogen and carbon dioxide at 500 K
by reforming under aqueous conditions. The process can be applied to all carbohydrates found in wastewater from biomass processing of cheese whey, beer brewery,
sugar processing as well carbohydrate streams from agricultural products, such as
corn and sugar beets and hemicellulose from any biomass [4,15]. Typical feedstock
that can be used for APR and bioforming process are listed in Table 6.1 [4,15]. The
secondary feedstock mentioned in the table are first converted to primary feedstock
(by hydrolysis and/or hydrogenation processes depending on the feedstock), before
using them for APR process. The produced hydrogen can be used to hydrogenate
many components of lignocellulosic biomass to produce glycols and other polyols,
thus enlarging the feedstock possibilities for APR. The hydrogen can also be used to
produce ammonia and fertilizer, an additive to gasification products to produce liquid fuels via FT synthesis and fuel source for polymer electrolyte membrane (PEM)
fuel cells.
Besides hydrogen, APR can also produce syngas (CO and H 2 ), alkanes, and monofunctional groups depending on the nature of the catalyst and the operating conditions. As will be discussed later, the production of hydrogen and syngas requires the
breakage of C–C bonds within oxygenated compounds, whereas the production of
alkanes and monofunctional groups requires the breakage of C–O bonds within the
oxygenated compounds. With most feedstock examined so far, the alkane production is limited to six carbon atoms. More feedstock, catalysts, and reactor designs are
needed to produce C 8 –C 15 alkanes from the biomass-derived reactants. The alkanes
and monofunctional groups can be further upgraded catalytically by creating new
C–C bondages (through condensation reactions) to produce higher alkanes and liquid fuels. The light fuel additives such as pentane and hexane have limited values
due to their high volatility. Various reaction paths that can be produced by APR
process are schematically illustrated in Figure 6.1 [4].