Biomedical Engineering Reference
In-Depth Information
hydrolysis has been established and passed identification by the Ministry of Science
and Technology, China. The project uses sawdust and rice husk as raw materials,
and allegedly the cost is about 6,000 RMB for each ton of ethanol.
6.3
Biohydrogen
6.3.1
Introduction of Hydrogen Energy
Cleanliness, efficiency, and renewability are the focus of new energy. Hydrogen
satisfies these conditions. Hydrogen is a secondary energy, compared with other
kinds of energy; it has the following significant advantages:
(1) Hydrogen itself is nontoxic. When burned, its only by-products are water and
a little nitride hydrogen, not like fossil fuels, which generate large amounts of
soot agent, CO, CO
2
, hydrocarbons, lead compounds, and so on. The small
amount of nitride hydrogen would not pollute the environment after treatment,
so hydrogen provides the cleanest energy.
(2) The combustion property of hydrogen is good. It is easy to light and burns fast.
It has a wide combustible range mixed with air. Except for nuclear fuel, the
heating value of hydrogen is the highest of all fossil fuels, chemical fuels, and
biofuels. The combustion heats of hydrogen and gasoline are as follows:
Combustion heat of hydrogen
W 2
H
2
C
O
2
! 2
H
2
O
C 115:60
kcal
Combustion heat of gasoline
W
C
5
H
12
C 8
O
2
! 5
CO
2
C 5
H
2
O
C 781
kcal
kg
1
,
Converted into combustion heat per kilogram, hydrogen is 28,900 kcal
kg
1
. Therefore, the combustion heat of hydrogen
is nearly three times the combustion heat of gasoline, which is about 4.5 times
the combustion heat of coke.
(3) The thermal conductivity of hydrogen is the best of all gases—11 times the
majority of the others. Therefore, hydrogen is an excellent heat transfer carrier
in the energy industry.
(4) Hydrogen can be used in many cases. For example, it can be used as engine
fuel directly, chemical raw materials, fuel cell fuel [
45
,
46
], structural materials
(solid-state hydrogen), and more. It does not require major transformation of
the existing technology and equipment to use hydrogen instead of coal and oil.
The existing internal combustion engine needs only a little modification so it
can be used.
(5) Hydrogen can exist as metal hydrides in the gas, liquid, or solid state. It can
satisfy storage, transportation, and various different application environment
requirements.
while gasoline is 10,848 kcal
