Method and apparatus for sequentially staged combustion using a catalyst

A method of combusting a fuel in air, comprising the steps of:

• a) mixing a first flow of fuel into a first flow of air so as to form a first fuel/air mixture;
• b) flowing said first fuel/air mixture through a combustion catalyst, thereby producing a catalyzed fuel/air mixture;
• c) combusting said catalyzed fuel/air mixture, thereby producing a combusted gas;
• d) mixing a second flow of fuel into a second flow of air so as to form a second fuel/air mixture;
• e) combusting said second fuel/air mixture by mixing said second fuel/air mixture into said combusted gas so as to raise the temperature of said second fuel/air mixture above its ignition temperature, thereby producing a further combusted gas;
• f) mixing a third flow of fuel into a third flow of air so as to form a third fuel/air mixture;
• g) combusting said third fuel/air mixture by mixing said third fuel/air mixture into said further combusted gas, thereby raising the temperature of said third fuel/air mixture above its ignition temperature, thereby producing a still further combusted gas;
• and
• h) transferring heat from said still further combusted gas to said first fuel/air mixture for heating said first fuel/air mixture prior to flowing said first fuel/air mixture through said combustion catalyst.

The method according to claim 14, wherein:

• a) the step of combusting said catalyzed fuel/air mixture occurs in a first combustion zone of a combustor, said first combustion zone disposed downstream from said catalyst;
• b) the step of mixing and combusting said second fuel/air mixture occurs in a second combustion zone disposed downstream from said first combustion zone;
• and
• c) the step of mixing and combusting said third fuel/air mixture occurs in a third combustion zone disposed downstream from said second combustion zone.