Measurement and Prediction of Instability in Certain Exothermic Vapor Phase Reactors
September 17th, 1972
Paper to the American Chemical Society Symposium Series 109 (Advances in Chemistry) 610 in 1972
S F Bush
Introduction
The experiments and mathematical analysis abstracted here were prompted by the observation, on the industrial scale, of a sudden instability in certain vapor-phase chlorine-hydrocarbon reactions. Reactions of this sort are often carried out in reactors where the velocities have been deduced from calculation and measurement on the laboratory scale. Under normal conditions the reaction of chlorine to completion occurs in the region below the injection point, but under some conditions the reaction ceases abruptly, and unreacted chlorine leaves this region to react eventually elsewhere in a dangerous and uncontrolled manner.
The steady reaction states observed cannot be regarded as unstable to infinitesimal disturbances since reaction is typically maintained for periods which are long compared with the time for such disturbances to pass through the system. The sudden cessation of reaction can be explained, however, as a result of a sufficiently large disturbance being applied to a system which is locally stable.
The stability of the systems studied is characterized as the time in seconds for which a given percentage reduction in the flow of the leaner feed component (usually chlorine) will just permit the system to recover. Experiments of this sort have been carried out in laboratory reactors with methyl chloride and methane as the hydrocarbon feedstocks.