Page 54 - Biofuels Refining and Performance

Energy and Its Biological Resources 37

1.16 Hydrogen
The simplest of the elements, containing a single proton and electron
each, of mass almost unity, is the first member of the periodic table.
Data may vary from different sources; solid at 4.2 K (d 0.089), H has
the atomic number (AN) 1, atomic weight (AW) 1.008 g, melting point
(mp) 259.14 C, and boiling point (bp) 252.87 C (d 0.071 at 20.4 K).
He has a AN 2, AW 4.0026 g, mp 272.2 C (20 atm), and bp 268.93 C
(specific gravity 0.124).
Commercial consumption at present is mostly in synthetic fuels, say
from coal, mineral oils, petroleum reformation (refineries), and iron and
copper ore reductions. Hydrogen is very important because of the ver-
satility of its physical, chemical, and biological properties. More impor-
tantly for our purposes, is its potential as a source of energy. Hydrogen
liquefies at 33.2 K, 12.8 atm, and 0.03 g/mL and occupies a negligible
volume (22.4 times less), compared to its gaseous state. Solid hydrogen
and helium are academic ideas. When hydrogen combines with oxygen
in a volume ratio of 2:1, heat is generated and the product is water in
a vapor state. The reaction in a vapor state occurs with a reduction of
1
1
volume to / 3 and water vapor to water / 22, which means the reaction is
favored at a higher pressure; alternatively, the change in volume is
compensated by utilizing some of the heat that evolves. The calculations
are already there. Hydrogen as a combustion fuel or as a material for a
fuel cell is less attractive than the fusion reaction such as that which
occurs in the sun. Taking it as a model, we may be able to harness huge
amounts of thermal and traditional energies, but we should also learn
how to manage and handle such enormous outbursts of energy. Two
protons fuse to yield a deuterium, a positron, and a neutrino; the last
one is the clue to the release of energy that is not yet fully understood
by science;

1

1
2
3
3
4
2H → e H 2 H H → H 2H → He 2H 1
2
33
2
Solar constant 1.968 cal/(cm
min) 3.86 10 erg/s 1.373 kW/m ;
even at such a long distance, we are unable to use all the energies.
Hydrogen in absence of air or oxygen, or in vacuum, will not burn, but
may have a kind of combustion to produce ammonia in air or nitrogen.
Combustion of hydrogen in our atmosphere does not produce simple
(nitrogen and
water vapor, but mixture of others, i.e., ammonia and NO xS
oxygen combine at the vicinity of high temperature generated).
Cryogenic and space research have taught us many more lessons.
Liquid hydrogen can be stored in special containers (cylinders), or trans-
ported through pipes, and is almost an ideal fuel for rockets and space-
ships, perhaps next to azides. But at higher altitudes or in space, in the
absence of atmosphere, optimal liquid oxygen is also needed to perform