A multiloop control system and an on-line reactor operability analysis were developed for the purpose of detecting and averting extinction of the autothermal state of a laboratory catalytic reactor. The reactor system consisted of a feed-effluent heat exchanger and two packed beds in which the exothermic reaction between hydrogen and oxygen occurred.The strategy of control was based on the preservation of the relative stability of the autothermal steady state when the reactor experienced large changes in feed concentration and flow rate. Such a strategy involved a model-based prediction of reactor conditions that so preserved stability, and a procedure to guide the process rapidly and smoothly to those new conditions. Experiments demonstrated the successful avoidance of extinction and the orderly attainment of new operating conditions in about three reactor-system time constants. The procedures developed could serve as a component of an on-line expert system for safe reactor operations.

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