Propene ammoxidation over an industrial bismuth molybdate-based catalyst using forced dynamic operation

Abstract

Propene ammoxidation to acrylonitrile (ACN) over bismuth molybdate-based catalysts has been commercialized for more than 60 years. To meet forecasted growth, there is an opportunity for smaller-scale, decentralized ACN production. Forced dynamic operation (FDO), here referring to step changes in reactant inlet concentrations, has been used in low-volume production applications and has shown advantages in partial oxidation reactions. As a proof-of-concept study to evaluate FDO for acrylonitrile production, we applied periodic changes in inlet gas concentrations that varied between one phase containing all reactants and another that just contained O2, over an industrial bismuth molybdate-based catalyst. We varied the cycle period, duty cycle, and O2 concentration in the second phase and show that improved acrylonitrile yields can be obtained compared with those of steady-state operation under certain conditions. A correlation between lattice oxygen availability and FDO performance was observed.