8
Thermal Process Safety
8.1
Thermal Process Safety as a Part of Process Risk
Assessment
To be economically efficient, chemical production on an industrial scale often
requires high productivity through the use of large production volumes and high
concentrations. Consequently, this can be associated with the generation of considerable amounts of thermal energy too large to be absorbed by the environment
surrounding the system. The topic of thermal process safety aims to address
specifically this key hazard that can exist within many chemical processes.
Instead of having its own set of specific steps, it is rather embedded within the
more general framework of chemical process risk assessment introduced in Chap. 7.
As thermal process safety is fundamental for the design of inherently safe processes
and the definition of safe process conditions during the early stages of process
development, this chapter is dedicated specifically to introducing this topic and
some of the most important physicochemical phenomena that shape it.
In the field of thermal process safety, the basic principles of thermodynamics,
chemical kinetics, and reaction engineering are used to identify thermal hazards and
define safe process conditions. Here, a thermal hazard is referred to as the potential
of a chemical system to cause a significant increase in temperature and/or pressure
that cannot be absorbed by its surroundings. This can be the result of, for example,
highly exothermic decomposition reactions.
One of the most fundamental concepts related to thermal hazards is the thermal
runaway. A thermal runaway is an uncontrolled reaction that acts as a feedback
loop. Strong exothermic reactions are accelerated by a temperature rise, which leads
to yet further and more rapid increases in temperature and pressure. Left unchecked,
these reactions can lead to a thermal explosion. Preventing such runaway reactions
is therefore clearly of significant relevance to chemical process safety.
Runaway reactions are the result of the insufficient removal of heat, normally
from large units such as reactors and storage vessels on an industrial scale. In storage
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
K. Hungerbühler et al., Chemical Products and Processes,
https://doi.org/10.1007/978-3-030-62422-4_8
199
Thermal Process Safety
8.1
Thermal Process Safety as a Part of Process Risk
Assessment
To be economically efficient, chemical production on an industrial scale often
requires high productivity through the use of large production volumes and high
concentrations. Consequently, this can be associated with the generation of considerable amounts of thermal energy too large to be absorbed by the environment
surrounding the system. The topic of thermal process safety aims to address
specifically this key hazard that can exist within many chemical processes.
Instead of having its own set of specific steps, it is rather embedded within the
more general framework of chemical process risk assessment introduced in Chap. 7.
As thermal process safety is fundamental for the design of inherently safe processes
and the definition of safe process conditions during the early stages of process
development, this chapter is dedicated specifically to introducing this topic and
some of the most important physicochemical phenomena that shape it.
In the field of thermal process safety, the basic principles of thermodynamics,
chemical kinetics, and reaction engineering are used to identify thermal hazards and
define safe process conditions. Here, a thermal hazard is referred to as the potential
of a chemical system to cause a significant increase in temperature and/or pressure
that cannot be absorbed by its surroundings. This can be the result of, for example,
highly exothermic decomposition reactions.
One of the most fundamental concepts related to thermal hazards is the thermal
runaway. A thermal runaway is an uncontrolled reaction that acts as a feedback
loop. Strong exothermic reactions are accelerated by a temperature rise, which leads
to yet further and more rapid increases in temperature and pressure. Left unchecked,
these reactions can lead to a thermal explosion. Preventing such runaway reactions
is therefore clearly of significant relevance to chemical process safety.
Runaway reactions are the result of the insufficient removal of heat, normally
from large units such as reactors and storage vessels on an industrial scale. In storage
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
K. Hungerbühler et al., Chemical Products and Processes,
https://doi.org/10.1007/978-3-030-62422-4_8
199