Environmental Engineering Reference
In-Depth Information
First, the energy with certain form transforms to the compressing energy of prod-
ucts. Then the compressed materials expand rapidly, while the compressing energy
changes into mechanical energy, which leads to the shape change, damage, or shift
of the around media. Physical change leads to physical explosion, while chemical
change results in chemical explosion.
In our daily life, the most common physical explosion is lightning. It is a spark
discharge. Within the discharge space, the energy density and temperature of the
media raise to an unbelievable high condition (e.g., several ten kilo degrees Celsius)
within extreme short time. This leads to the fast pressure increase of the discharged
air and explosion. All explosions from high-pressure cookers, steam boiler, high-
pressure compressed gas cylinders, and earthquakes are physical ones.
Explosions from lique
ed gas pipes, gasoline tanks, chemical processes of
industry, gas inside mines, coal dust, and all explosive materials are chemical
explosions. The explosion caused by mixtures of in
ammable liquid leakage and air
is also chemical one. All staffs, which can have chemical explosions, are named
explosives. If the used staff is in liquid or sol-gel, this is the explosion from liquid
explosive materials. This chapter studies the explosion variation law and features of
liquid explosive materials.
The explosive abilities are determined by the exothermicity, rapidity, and gas
production of explosion reaction.
fl
2.1.1 Heat/Energy Releasing of Liquid Explosive Explosion
All explosion reactions are exothermic with the formation of new molecules.
Considering the decomposition of a compound, certain amount of energy must be
supplied to activate the molecules or break the chemical bonds, which subsequently
generate new compound and release heat. If the released heat cannot activate the
subsequent reactions, the chemical reactions will terminate automatically. To
maintain such a reaction, energy has to be supplied from the environment. Obvi-
ously, these materials are not explosives. If the energy released from the initial
explosive reaction activates the unreacted molecules, and the explosive reaction
propagates continually until all reactants are consumed.
Explosion is a process in which energy transforms rapidly. Explosion produces
stable compounds by transforming chemical energy into heat. The heat is then
transformed into the mechanical work of media. Endothermic reactions or exo-
thermic reactions with less heat released are not explosion. For example,
ð
NH
3
Þ
2
C
2
O
2
¼
2NH
3
þ
H
2
O
þ
CO
þ
CO
2
263
:
6kJ
ZnC
2
O
4
¼
Zn
þ
2CO
2
205
:
4kJ
PbC
2
O
4
¼
Pb
þ
CO
2
69
:
87 kJ
CuC
2
O
4
¼
Cu
þ
CO
2
þ
23
:
85 kJ
HgC
2
O
4
¼
Hg
þ
2CO
2
þ
47
:
28 kJ
