Oscillatory thermal instability - the Bhopal disaster and liquid bombs

TL;DR

This paper investigates the mechanism of oscillatory thermal instability in liquid thermoreactive systems, such as those involved in the Bhopal disaster and liquid bombs, revealing a new type of thermal runaway caused by a subcritical Hopf bifurcation.

Contribution

It introduces a novel analysis of oscillatory thermal instability in liquids, demonstrating the role of subcritical Hopf bifurcations in thermal runaway phenomena.

Findings

Thermal runaway involves large amplitude oscillations.

Oscillatory instability is initiated at a subcritical Hopf bifurcation.

Classical ignition theory cannot predict this type of thermal behavior.

Abstract

Thermal runaway reactions were involved in the Bhopal disaster of 1984, in which methyl isocyanate was vented from a storage tank of the liquid, and occur in liquid peroxide explosions, yet to date there have been few investigations into the mechanism of thermal runaway in such liquid thermoreactive systems. Consequently protocols for storing thermally unstable liquids and deactivating liquid bombs may be suboptimal. In this work the hydrolysis of methyl isocyanate and the thermal decomposition of triacetone triperoxide were simulated using a gradientless, continuous-flow reactor paradigm. This approximation enabled stability analyses on the steady state solutions of the dynamical mass and enthalpy equations. The results indicate that thermal runaway in both systems is due to the onset of a large amplitude, hard thermal oscillation initiated at a subcritical Hopf bifurcation. This type of thermal misbehaviour cannot be predicted using classical ignition theory, and may be typical of liquid thermoreactive systems. The mechanism of oscillatory thermal instability on the nanoscale is elucidated.