Experimental analysis of critical operating parameters on heat storage and oxidation performances in a VAM-fueled flow-reversal reactor

This work presents an experimental investigation of heat storage and oxidation of a ventilation air methane-fueled flow-reversal reactor with three fixed beds and air sweeping. Effects of the gas flow rate, methane concentration, switching, and sweeping time are systematically explored and analyzed. Results indicate that both system temperature and methane conversion rate are periodically changed with time. There is a critical gas flow rate, above which the combustor average temperature and methane concentration rate are less affected. Meanwhile, the minimal methane concentrations for the system maintaining sustained thermal equilibrium are identified. Varying the gas flow rate from 950 to 1350 m3/h enables the minimum auto-thermal methane concentration to be reduced from 0.76 % to 0.64 %, an approximate percentage drop of 15.8 %. Further, decreasing the switching time is beneficial to elevating the average temperature by approximate 13.4 °C and narrowing down the oscillation amplitude, thus facilitating the system stability. This is mostly because the high-temperature exhausted gases are more likely to be trapped in the combustion chamber, thus enhancing heat transfer. Finally, the average temperature is shown to have a non-monotonic dependence on the sweeping time with the optimal time of 20 s.