157
Aqueous-Phase
6
Reforming and
BioForming Process
6.1 intrOdUCtiOn
In Chapter 5, we examined the conversion of biomass to biochar, bio-oil, and fuel
gases such as methane and hydrogen in water at high temperature and pressure but
under subcritical conditions. We showed that water under high-temperature and highpressure conditions possesses unique physical and chemical properties that allow its
strong interactions with biomass to generate solid, liquid, and gaseous fuels. Water,
in this case, not only acts as a solvent but also as a reactant and a catalyst to carry
out wet pyrolysis reactions. The quality of products depends on the reaction temperature, pressure, reaction time as well as the presence of any catalyst. The chapter
also showed that water at high temperature possesses the properties very similar to
several organic chemicals and is capable of carrying out various types of organic
chemical reactions. While the level of the conversion by the hydrothermal processes
(hydrothermal carbonization [HTC], hydrothermal liquefaction [HTL], or hydrothermal gasification [HTG]) can be improved with the use of a suitable catalyst, these
processes are basically nonselective.
Biomass can produce hydrogen and liquid fuels in a number of different ways.
These production methods can be thermochemical, biochemical, or catalytic.
Current processes to convert biomass to liquid fuels include (1) fermentation of
glucose to ethanol, (2) pyrolysis or high-pressure liquefaction of biomass to bio-oils,
(3) gasification of biomass to syngas followed by Fischer–Tropsch (FT) synthesis
to alkanes, (4) anaerobic digestion of cellulosic waste to produce hydrogen and
methane, (5) Mobil process of conversion of carbohydrates to aromatic hydrocarbons and coke with Zeolite Socony Mobil (ZSM)-5 catalyst, and (6) supercritical
water extraction or gasification of biomass to hydrogen or liquid fuels. In this
chapter, we describe yet another selective process to generate hydrogen, syngas,
alkanes, and monofunctional groups using low-pressure catalytic process in an
aqueous environment. Monofunctional groups can also be further upgraded to
various liquid fuels (such as diesel, gasoline, and jet fuel) using a selective catalytic process known as “bioforming process.” Numerous excellent reviews on
both aqueous-phase reforming (APR) and bioforming process are available in the
literature [1–14].
We briefly examine in this chapter a set of catalytic reactions that can be carried
out for a select group of oxygenated compounds such as sugar, glucose, sorbitol,
Aqueous-Phase
6
Reforming and
BioForming Process
6.1 intrOdUCtiOn
In Chapter 5, we examined the conversion of biomass to biochar, bio-oil, and fuel
gases such as methane and hydrogen in water at high temperature and pressure but
under subcritical conditions. We showed that water under high-temperature and highpressure conditions possesses unique physical and chemical properties that allow its
strong interactions with biomass to generate solid, liquid, and gaseous fuels. Water,
in this case, not only acts as a solvent but also as a reactant and a catalyst to carry
out wet pyrolysis reactions. The quality of products depends on the reaction temperature, pressure, reaction time as well as the presence of any catalyst. The chapter
also showed that water at high temperature possesses the properties very similar to
several organic chemicals and is capable of carrying out various types of organic
chemical reactions. While the level of the conversion by the hydrothermal processes
(hydrothermal carbonization [HTC], hydrothermal liquefaction [HTL], or hydrothermal gasification [HTG]) can be improved with the use of a suitable catalyst, these
processes are basically nonselective.
Biomass can produce hydrogen and liquid fuels in a number of different ways.
These production methods can be thermochemical, biochemical, or catalytic.
Current processes to convert biomass to liquid fuels include (1) fermentation of
glucose to ethanol, (2) pyrolysis or high-pressure liquefaction of biomass to bio-oils,
(3) gasification of biomass to syngas followed by Fischer–Tropsch (FT) synthesis
to alkanes, (4) anaerobic digestion of cellulosic waste to produce hydrogen and
methane, (5) Mobil process of conversion of carbohydrates to aromatic hydrocarbons and coke with Zeolite Socony Mobil (ZSM)-5 catalyst, and (6) supercritical
water extraction or gasification of biomass to hydrogen or liquid fuels. In this
chapter, we describe yet another selective process to generate hydrogen, syngas,
alkanes, and monofunctional groups using low-pressure catalytic process in an
aqueous environment. Monofunctional groups can also be further upgraded to
various liquid fuels (such as diesel, gasoline, and jet fuel) using a selective catalytic process known as “bioforming process.” Numerous excellent reviews on
both aqueous-phase reforming (APR) and bioforming process are available in the
literature [1–14].
We briefly examine in this chapter a set of catalytic reactions that can be carried
out for a select group of oxygenated compounds such as sugar, glucose, sorbitol,