Although the oxidation of carbon monoxide on platinum is one of the oldest known catalytic reactions and one of the most thoroughly studied, it continues to pose difficulties and challenges to both the experimentalist and the theoretician. For the most part, these are due to the frequent observations of hysteresis, associated with steady-state multiplicity, and self-sustained oscillations in the reaction and to the fact that no generally accepted theoretical explanation for them is at hand. even though a large number of studies have addressed the subject.

Intrinsically Unstable Behavior during the Oxidation of Carbon Monoxide on Platinum

Multiplicities and instabilities in chemically reacting systems — a review

Publisher Summary This chapter focuses on the oscillatory reactions in heterogeneous catalysis. Oscillations are possible on all levels in a catalytic reactor, from the single-crystal plane to the crystallite to the catalyst pellet to the packed-bed reactor, and each level adds another degree of complexity. So, it is necessary to isolate the major influences at each level and to separate the characteristics of the oscillations on one level from the effects caused by coupling with other levels. Only when each level is well understood is it possible to fully understand the overall oscillatory behavior. Oscillations in heterogeneous catalysis, therefore, remain an intriguing and demanding problem. There are four primary reasons for studying oscillatory catalytic reactions. (1) Many surface reactions oscillate; probably all bimolecular oxidation reactions on transition metals will exhibit oscillations under some conditions. (2) They are intriguing and poorly understood phenomena, with no universally acknowledged mechanism. (3) Oscillatory states of reactors are potentially dangerous in chemical plants. In order to avoid these states, it is important to learn about the conditions favoring the occurrence of oscillations. (4) In spite of the potential hazards of oscillatory states, there are in some cases possible benefits to operating reactors in unstable regimes.

Oscillatory Reactions in Heterogeneous Catalysis

Nonlinear feedback control for operating a nonisothermal CSTR near an unstable steady state

From a one-point iterative method of R-order at least three, we construct new two-point iterations to solve nonlinear equations in Banach spaces such that the computational cost is reduced, whereas the R-order of convergence is increased to at least four.

D.D. Bruns

Papers

Nonlinear feedback control for operating a nonisothermal CSTR near an unstable steady state

Isothermal sustained oscillations due to the influence of adsorbed species on the catalytic reaction rate

Process operation near an unstable steady state using nonlinear feedback control