Method and system for combusting a fuel

A method of combusting fuel comprising:

• introducing an oxygen-containing stream into at least one oxygen transport membrane projecting into a separation zone to separate oxygen from said oxygen-containing stream and thereby, to introduce an oxygen permeate into said separation zone;
• heating the at least one oxygen transport membrane to an operational temperature;
• introducing a fuel stream into a combustion zone to combust and thereby to produce a flue gas stream;
• circulating a sweep gas stream, composed of part of said flue gas stream, within the separation zone;
• and
• circulating said sweep gas stream from said separation zone to said combustion zone to support combustion of said fuel stream.

An oxygen enhanced combustion system comprising:

• at least one oxygen transport membrane located within a combustion zone to separate said oxygen from an oxygen-containing stream introduced into said at least one oxygen transport membrane, thereby to produce an oxygen permeate;
• at least one fuel nozzle for injecting a fuel stream of the fuel into said combustion zone so that said at least one oxygen transport membrane is subjected to a reactive purge produced by combustion of the fuel in the presence of said oxygen permeate and a portion of heat arising from the combustion of the fuel heats said at least one oxygen transport membrane to an operational temperature;
• and
• a heat sink positioned to absorb radiant heat energy emanating from said at least one oxygen transport membrane to promote stabilization of the operational temperature thereof.

An oxygen enhanced combustion system comprising:

• at least one oxygen transport membrane located within a separation zone to separate said oxygen from an oxygen-containing stream introduced into said at least one oxygen transport membrane;
• at least one nozzle for injecting a fuel stream into a combustion zone for combustion of said fuel to produce a flue gas stream;
• means for heating said at least one oxygen transport membrane;
• and
• means for circulating a sweep gas stream composed of a part of said flue gas stream into said separation zone and from said separation zone to said combustion zone to support combustion of said fuel stream.