Design and testing of small-scale unsteady-state afterburners and reactors

The design and testing of small-scale and pilot-scale apparatus using the reverse-flow concept is focused on. The combustion of lean air–methane mixtures was considered as a test reaction both for modeling purposes and for the experimental investigation. A one-dimensional two-phase model was used to highlight that thermal properties of the reactor wall and radial heat losses affect the thermal stability of bench-scale rigs more than that of large-scale industrial reactors, where adiabatic behavior is generally achieved. As a consequence, a special temperature-control system, based on dynamic compensation of the thermal losses, was designed to attain adiabatic operation in a small-scale apparatus, avoiding overcompensation and thus allowing the scale-up of the results obtained. This system was realized and tested, proving to be effective in a wide range of operating conditions such as inlet concentration and feed flow rate.