Millisecond catalytic wall reactors: I. Radiant burner

Short-contact-time reactors have potential for high throughput in reactors much smaller than their traditional counterparts. While they operate adiabatically, heat can be exchanged at short contact time by integrating heat exchange into the reactor. Hot effluent of exothermic reaction systems can be redirected over feed gases to recuperate a portion of the sensible heat. Placing catalyst directly on reactor walls eliminates the resistance to heat transfer in the thermal boundary layer so that heat released by combustion can be effectively coupled to an emitter, such as in a radiant burner. A radiant heater was constructed operated, and simulated incorporating short contact time, energy recuperation, and a catalytic wall. This burner operated stably for many hours at a filing rate from similar to 50 to > 160 kW/m(2) at a radiant temperature of 950 to 1,150 K at a radiant efficiency of similar to 60% with a residence time in the reacting zone of similar to 10 ms. This reactor was modeled using 2-D Navier-Stokes equations including detailed models for chemistry and heat transport. Temperature and compositions predicted agreed well with experimental measurements.