Environmental Engineering Reference
In-Depth Information
Table 7.46 Thermochemical performance of hydrogen peroxide
Parameters
Concentration of H 2 O 2 (%)
86
100
Decomposition heat (J/g)
2510.4
2886.96
Enthalpy of vaporization (J/g)
1652.68
1548.08
Adiabatic decomposition temperature
650
980
Volume after full adiabatic decomposition (L/kg)
4,900
6,400
Extensive experimental studies over the decomposition mechanism have shown
that the low thermodynamic energy for the reaction between H 2 and O 2 in boric
acid-coated old containers can be only understood by considering the chemical
inertness of the surface to water and H 2 O 2 [ 60 ]. It is reported that in such conditions
the decomposition of H 2 O 2 occurs in the temperature range of 260
520
°
C and the
-
parameters suggest a
first-order reaction.
The following reaction occurs spontaneously when H 2 O 2
is mixed with
hydrazine:
2H 2 O 2 þ NH 2 NH 2 H 2 O ! 5H 2 O þ N 2 þ 786 : 59 kJ
There is hysteresis in reaction, but copper salts if added, such as in the form of
K 3 Cu(CN) 4 can help catalyze the reaction and the salt dissolves into hydrazine
hydrate. It was further con
rmed that K 3 Cu(CN) 4 reacts with hydrazine at room
temperature to form copper metals whose accumulation could block hydrazine from
entering combustion chamber. To remove such a possibility, before entering
combustion chamber hydrazine hydrate should go through a cartridge of copper
nitrate which are able to accelerate the reaction.
The hydrogen peroxide solution treated with ammonium nitrate has been used as
the oxidant [ 61 ]. A solution of 40 % ammonia nitrate in 60 % H 2 O 2 is compelling
as the solidifying point is around
30
°
C.
7.6.2 Explosion Properties of H 2 O 2 and Its Mixtures
(a) Explosion Properties of H 2 O 2
The exothermic decomposition reaction of hydrogen peroxide indicates the
possibility to be used as explosive. In fact, lead block expansion value for 99.6 %
concentration H 2 O 2 is 75
80 cm 3 . In a steel tube of a diameter of 34
40 mm, 94
-
100 % of H 2 O 2 can be fully detonated with 50 g pentaerythritol tetranitrates.
However, for 92 % H 2 O 2 , the detonation can propagate 100 mm away from the
detonator.
No detonation occurs to 90 % concentration H 2 O 2 [ 61 ]. There are interesting
studies over the explosion properties of ternary mixture including H 2 O 2 , water, and
possible organic substances. There results [ 62 ] give the possibility that the ternary
-
-
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