Processes are provided for the production of styrene monomer by oxidative dehydrogenation of EB using CO2 as a soft oxidant. The frame defines a through hole therein, and the through hole includes an assembly hole and a location hole communicating with each other. The trapped exhaust gas is released from the EGR system into the intake manifold of the engine in response to detection of a second operating condition that is indicative of a subsequent increase in engine fueling rate above the minimum engine fueling rate.