Comparison of Design and Operation Strategies for Temperature Control during Selective Catalytic Reduction of NOx

The problem of controlling temperature profile along a monolithic reactor in which an exothermic reaction (selective catalytic reduction of NOxby hydrocarbons) takes place is considered. Several solutions are proposed and compared. It is shown that a near‐optimum temperature profile can be achieved by two rather different approaches – one based on periodic switching of a hot reactant and a cold inert stream between two thermally coupled monoliths, and one based on pre‐mixing the reactant and coolant streams. An adaptive control scheme based on model‐predictive control is proposed and shown to be efficient for the case of time‐variable properties of the reactant stream.