Catalytic combustion system and combustion control method

A combustion control method for use in a catalytic combustion system having

• (a) a gaseous mixture inlet port, located at the upstream side of said catalytic combustion system, for the entrance of a fuel-air mixture;
• (b) an exhaust gas outlet port, located at the downstream side of said catalytic combustion system, for the exit of an exhaust gas;
• (c) a primary constant combustion chamber in which a catalyst body is disposed, said catalyst body being formed of a porous base material with numerous communicating holes that supports thereon an oxidation catalyst;
• (d) an ignition unit located upstream from the first catalyst body;
• (e) a preheat burner located upstream from the first catalyst body;
• (f) a secondary supply port, located downstream of said primary combustion chamber, for the supply of a gaseous mixture of air;
• and
• (g) a secondary combustion chamber located downstream of said secondary supply port;
• comprising such process that
• an excess air ratio of said primary constant combustion chamber is initially set above 1 and after the rate of combustion of said secondary combustion chamber exceeds a given level, combustion is made to take place, with the excess air ratio of said primary combustion chamber set below 1, and
• with the excess air ratio set below 1, combustion is not complete in the primary combustion chamber.

A catalytic combustion system comprising:

• (a) a gaseous mixture inlet port, located at the upstream side of said catalytic combustion system, for the entrance of a fuel-air mixture;
• (b) an exhaust gas outlet port, located at the downstream side of said catalytic combustion system, for the exit of an exhaust gas;
• (c) a primary combustion chamber in which a first catalyst body is disposed, said catalyst body having a porous base material with numerous communicating holes that supports thereon an oxidation catalyst;
• (d) an ignition unit located upstream from the first catalyst body;
• (e) a preheat burner located upstream from the first catalyst body;
• (f) a glass located upstream of the first catalyst body and in a face to face arrangement therewith;
• (g) a secondary supply port, located downstream of said primary combustion chamber, for the supply of a gaseous mixture or air;
• and
• (h) a secondary combustion chamber located downstream of said secondary supply port;
• wherein an excess air ratio of said primary constant combustion chamber is initially set above 1 and after the rate of combustion of said secondary combustion chamber exceeds a given level, combustion is made to take place, with the excess air ratio of said primary combustion chamber set below 1, and
• with the excess air ratio set below 1, combustion is not complete in the primary combustion chamber.

A catalytic combustion system comprising:

• (a) a gaseous mixture inlet port, located at the upstream side of said catalytic combustion system, for the entrance of a fuel-air mixture;
• (b) an exhaust gas outlet port, located at the downstream side of said catalytic combustion system, for the exit of an exhaust gas;
• (c) a primary combustion chamber in which a first catalyst body is disposed, said catalyst body having a porous base material with numerous communicating holes that supports thereon an oxidation catalyst;
• (d) an ignition unit located upstream from the first catalyst body;
• (e) a preheat burner located upstream from the first catalyst body;
• (f) a glass located upstream of the first catalyst body and in a face to face arrangement therewith;
• (g) a secondary supply port, located downstream of said primary combustion chamber, for the supply of a gaseous mixture or air;
• and
• (h) a secondary combustion chamber located downstream of said secondary supply port;
• wherein an excess air ratio of said primary constant combustion chamber is initially set above 1 and after the rate of combustion of said secondary combustion chamber exceeds a given level, combustion is made to take place, with the excess air ratio of said primary combustion chamber set below 1;
• with the excess air ratio set below 1, combustion is not complete in the primary combustion chamber;
• and
• said oxidation catalyst comprises a platinum group metal.