Disclosed herein is a heat exchanger for transferring heat between a first gas flow and a second gas flow, the heat exchanger comprising at least two sectors; a first sector that is operative to receive a combustion air stream; and a second sector that is opposed to the first sector and that is operative to receive either a reducer gas stream or an oxidizer gas stream, and a pressurized layer disposed between the first sector and the second sector; where the pressurized layer is at a higher pressure than combustion air stream, the reducer gas stream and the oxidizer gas stream.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 The subject matter of the present invention was developed under a research contract with the U.S. Department of Energy (DOE), Contract No. DE-FE0009484. The government of the United States has certain rights in the invention.