Combustion process and apparatus therefore containing separate injection of fuel and oxidant streams

A method of combustion in a combustion chamber of a furnace a fuel with oxygen the oxygen contained in an oxidant gas, the combustion generating heat to raise the temperature of a load or the furnace itself the fuel and oxidant gas delivered to the combustion chamber by a burner apparatus, the burner apparatus comprising a burner block having cavity means including at least two fuel injectors for distributing the fuel in at least two fuel streams injected in the combustion chamber of the furnace, and at least one main oxidant cavity ending with an elongated orifice having a major axis along its largest dimension which is generally parallel to a surface of the load or furnace to be heated, the elongated orifice suitable for injecting a major portion of oxidant required for complete combustion of the fuel, wherein the elongated orifice directs the major portion of oxidant to converge toward the at least two fuel streams and toward the surface of the load or furnace to be heated in order to generate a broad flame substantially parallel to the surface to be heated, wherein the inner geometry of the main oxidant cavity comprises preferably four sections:

• a first section which is generally cylindrical and having an axis;
• a second section which is generally cylindrical, of the same diameter as the first section;
• the second section making an angle (B) with the axis of the first section;
• continuously attached to the second section is a third section, generally conical with diverging angles (C) ranging from about 10.degree. to about 120.degree.;
• and a fourth section connecting continuously the third section with the main elongated orifice, the method comprising injecting the fuel into the combustion chamber through said at least two fuel injectors and injecting said major portion of oxidant through said at least one main oxidant cavity into the combustion chamber and injecting a secondary oxidant around each of the at least two fuel injectors in order to increase flame luminosity by initiating combustion of the fuel before the major portion of oxidant intersects the at least two fuel streams in the combustion chamber, creating a fuel rich mixture between the load or furnace being heated and the major portion of oxidant;
• a) the amount of secondary oxidant providing from 0 to about 20% of the oxygen required for complete combustion of the fuel wherein said broad flame emanates as a single flame from the burner block;
• or
• b) the amount of secondary oxidant providing from about 20% to about 50% of the oxygen required for complete combustion of the fuel, wherein said broad flame emanates from the burner block as two or more separate flames.