Chemistry Reference
In-Depth Information
Chapter 11
High-Temperature Decomposition and Thermal
Explosion of Liquid Propellant Components:
Hydrogen Peroxide and Hydrazine
Abstract
Highly concentrated H
2
O
2
and hydrazine are energetic materials that have
been widely used in rocket and space engineering. Since these liquids undergo
heating in various systems over a very wide temperature range, the study of their
decomposition kinetics at these temperatures is of significant importance. Original
instruments for measuring very high and very low decomposition rates (correspond-
ing to almost the entire temperature interval of practical interest) of these liquids are
described. Data on the thermal explosion of highly concentrated H
2
O
2
and kinetic
constants for its homogeneous decomposition (corresponding to a range of decom-
position rates covering six orders of magnitude) are given for the first time. Data on
the rate of heterogeneous decomposition of highly concentrated H
2
O
2
on surfaces
of various practically interesting construction materials are presented. Similar data
for hydrazine are also given in this chapter.
11.1 Introduction
This chapter is devoted to a discussion of the macrokinetics and kinetics of the
thermal decomposition of highly concentrated liquid hydrogen peroxide (h/c H
2
O
2
)
and N
2
H
4
(hydrazine), which were selected from numerous liquid propellants for
reasons given below. Due to its high-energy and performance characteristics, h/c
H
2
O
2
has been used as an oxidizer in rocket engines and torpedoes as well as a
monopropellant in the catalytic units of space vehicle orientation and touchdown
engine systems for quite a long time. In the past few years its range of applications
has been significantly widening since, from an environmental safety point of view,
h/c H
2
O
2
has and will continue to have few competitors. Since the only products of
its decomposition are oxygen and water, h/c H
2
O
2
has been used in the life-support
systems of spacecraft. From a practical point of view it is worth noting that the high
reactivity of h/c H
2
O
2
means that if it is accidentally spilled it quickly converts into
water. However, the use of h/c H
2
O
2
is also associated with some problems due to
its low thermal stability and ability to decompose catalytically upon contact with
quite inert metals. Based on his personal experience of working in committees that
have investigated many accidents, the author of this topic came to the conclusion
that h/c H
2
O
2
can be considered the most dangerous (with respect to explosions
