Energy Extraction From a Porous Media Reciprocal Flow Burner With Embedded Heat Exchangers

Abstract

Superadiabatic combustion in porous media allows a stable burning of ultralean methane/air mixtures, far below flammability limits. The intrinsic heat regeneration process of the porous matrix and the low degree of thermal nonequilibrium between the gas and the solid phases maintain temperatures of less than 1600 K resulting in extremely low levels of CO and NOx production. Due to the transient nature of this phenomenon, a method to confine the combustion into a practical burner has been engineered. The Reciprocal Flow Burner (RFB) is an effective and simple system to achieve this result by arranging the reaction zone to travel back and forth along the length of the burner. This ultimately results in a relatively uniform temperature profile over the central zone of the reactor. Embedding heat exchangers into the ends of the bed makes it an appealing alternative for high-efficiency, low-emission heat generation. In the present work, experimental results are presented and compared to an earlier numerical model to provide a better understanding of heat extraction from a RFB.