T5-1 - A study into the explosive boiling potential of thermally stratified liquid-liquid systems that result from runaway reactions

Abstract

In the chemical industry, there are a number of reactions performed in mixed multi-phasic systems. In these systems, accidental loss of agitation might lead to a segregation of the phases and the occurrence of a runaway reaction in one of the phases. The reaction is performed under well-stirred conditions to obtain the desired product specifications. A malfunctioning of the stirrer will lead to a segregation between the aqueous phase and the organic phase in which the exothermic polymerization reaction proceeds. The occurrence of a rapid phase transition, or so-called “explosive boiling,” when a cold volatile liquid comes into the contact with a hot liquid or hot surface is a potential hazard in industry. The study described in the chapter focuses on the explosive boiling potential of thermally stratified liquid-liquid systems that result from a runaway reaction. The experimental results showed that under the given conditions, the cold phase superheates but cannot evaporate explosively as the limits of superheat of the phase are not achieved. The response of the cold phase appeared to be completely controlled by the interface temperature between the hot and the cold phase. Based on the order of magnitude of temperature differences that result from a runaway reaction in a multi-phasic system and the fact that the system is pressurized by its own vapor pressure, the occurrence of explosive boiling under runaway conditions appears unlikely for these types of systems.