Environmental Engineering Reference
In-Depth Information
3.2 Design of Explosion Property [
7
]
Explosion property of explosive is related to its explosion heat. In a chemical
reaction under certain conditions, the released or absorbed heat is the thermal effect
of reaction.
When all elements react to form 1 mol of a substance, the released or adsorbed
heat is formation heat of the substance. When 1 mol of the substance was com-
busted in pure oxygen, the released heat is combustion heat; when 1 mol of
explosive was exploded under anaerobic conditions, the released heat is explosion
heat, which is different from combustion heat because combustion heat is the heat
released from complete oxidation of combustible components in a material.
According to Kirchhoff:
X
C
0
1
X
C
0
2
¼
X
dQ
dT
¼
D
C
0
ð
3
:
5
Þ
Thermal effect change with temperature is equal to the thermal capacity differ-
ence between the staring material and the
final material, which can be expressed as
the following:
Z
T
2
X
X
D
C
0
T
2
T
1
Q
2
¼
Q
1
þ
D
C dT
¼
Q
1
þ
ð
Þ
ð
3
:
6
Þ
T
1
According to the
first law of thermodynamics, the following equation can be
obtained:
D
E
¼
Q
þ
A
¼
Q
þ
P
D
V
ð
3
:
7
Þ
where,
E
internal energy,
ʔ
E
the change of E,
Q
released heat,
A
work done by the material,
P
Pressure of material,
ʔ
V
volume change of material.
If the reaction is carried out with constant volume,
ʔ
V = 0, the following can be
obtained,
0
Q
v
¼
D
E
A
¼
ð
3
:
8
Þ
