Hydrogen
247
• “Refilling time,” which for a battery is recharging time, is much
larger than the filling time of a traditional fuel tank (more than an
order of magnitude).
One can thus conclude that although electricity is a very useful and flexible energy carrier, other carriers that would overcome the need of wires to
distribute and/or can be stored in a more effective way, would have a large
impact on the future way of life for mankind.
9.2.3 role of Hydrogen
When hydrogen is put in contact with oxygen, it reacts with it, releasing large
quantities of energy. If this contact is direct, the released energy takes the form
of heat. If it is made by first ionizing hydrogen and using different paths for
ions and electrons, it takes the form of electricity (thermodynamics of the two
reactions are different, the differences in the amounts of potentially available
energy are not very large however, and are disregarded in this reasoning). As
a consequence of this, given the wide availability of oxygen in the air, it can be
said that hydrogen carries energy with itself. On the other hand, hydrogen is
not available free in nature, it is embedded in a lot of natural substances such
as water, carbohydrates, and hydrocarbons. To draw hydrogen from these
substances, energy must be spent. If, for instance, hydrogen is taken out of
water using electrolysis, the theoretical energy needed for this operation is the
same theoretically made available during hydrogen recombination with oxygen. These twin reactions that allow creation of hydrogen from natural substances (e.g., water) with energy expense and recreation of water by hydrogen
reaction with oxygen, makes it possible to use hydrogen as an energy carrier.
9.3 Hydrogen Production
Hydrogen can be produced from renewable as well as nonrenewable fuels
sources. Renewable fuel sources includes water, biomass, and from conventional fuels. Fuel processing technologies convert a hydrogen containing material such as gasoline, ammonia, or methanol into a hydrogen rich
stream. Fuel processing of methane is the most common hydrogen production method in commercial use today. Figure 9.1 shows the various hydrogen
production technologies (Holladay et al. 2009).
9.3.1 Hydrocarbon reforming
There are three primary techniques used to produce hydrogen from hydrocarbon fuels: steam reforming, partial oxidation (POX), and auto thermal
247
• “Refilling time,” which for a battery is recharging time, is much
larger than the filling time of a traditional fuel tank (more than an
order of magnitude).
One can thus conclude that although electricity is a very useful and flexible energy carrier, other carriers that would overcome the need of wires to
distribute and/or can be stored in a more effective way, would have a large
impact on the future way of life for mankind.
9.2.3 role of Hydrogen
When hydrogen is put in contact with oxygen, it reacts with it, releasing large
quantities of energy. If this contact is direct, the released energy takes the form
of heat. If it is made by first ionizing hydrogen and using different paths for
ions and electrons, it takes the form of electricity (thermodynamics of the two
reactions are different, the differences in the amounts of potentially available
energy are not very large however, and are disregarded in this reasoning). As
a consequence of this, given the wide availability of oxygen in the air, it can be
said that hydrogen carries energy with itself. On the other hand, hydrogen is
not available free in nature, it is embedded in a lot of natural substances such
as water, carbohydrates, and hydrocarbons. To draw hydrogen from these
substances, energy must be spent. If, for instance, hydrogen is taken out of
water using electrolysis, the theoretical energy needed for this operation is the
same theoretically made available during hydrogen recombination with oxygen. These twin reactions that allow creation of hydrogen from natural substances (e.g., water) with energy expense and recreation of water by hydrogen
reaction with oxygen, makes it possible to use hydrogen as an energy carrier.
9.3 Hydrogen Production
Hydrogen can be produced from renewable as well as nonrenewable fuels
sources. Renewable fuel sources includes water, biomass, and from conventional fuels. Fuel processing technologies convert a hydrogen containing material such as gasoline, ammonia, or methanol into a hydrogen rich
stream. Fuel processing of methane is the most common hydrogen production method in commercial use today. Figure 9.1 shows the various hydrogen
production technologies (Holladay et al. 2009).
9.3.1 Hydrocarbon reforming
There are three primary techniques used to produce hydrogen from hydrocarbon fuels: steam reforming, partial oxidation (POX), and auto thermal