METHOD OF STAGED COMBUSTION USING PREHEATED OXIDANT Russian patent published in 2009 - IPC F23D14/22 

FIELD: power engineering.

SUBSTANCE: method of fuel combustion when at least one fuel and at least two oxidants are injected: the first oxidant is injected at I₁ distance equal to 20 cm at maximum and preferably 15 cm at maximum from point of fuel injection. The second oxidant is injected at I₂ distance from point of fuel injection while I₂ is greater than I₁. Oxidants are injected in such amounts that sum of their amounts is equal to at least stoichiometric amount of oxidant required to provide combustion of injected fuel. The first oxidant is oxygen-enriched air at maximum temperature of 200 °C, and the second oxidant is air preheated to temperature of at least 300 °C. Air is enriched with oxygen so that oxygen concentration in enriched air is at least 30%. Oxygen-enriched air is obtained by mixing ambient air with oxygen from cryogenic source. Preheated air is heated by means of heat exchange using part of hot combustion products. At least two oxidants are injected at I₁ distance equal to 20 cm at maximum and preferably 15 cm at maximum while one oxidant called primary is injected mixed with fuel or near fuel and another oxidant called secondary is injected at distance from fuel. Amount of oxidant injected by means of primary oxidant jet ranges from 2 to 50% of oxygen stoichiometric amount required to provide combustion of injected fuel. The secondary oxidant is separated into multiple jets of secondary oxidant. The second oxidant injected at distance I₂ is separated into multiple jets of oxidant.

EFFECT: fuel combustion using oxygen as oxidant suitable for retrieving energy from furnace gases.

8 cl