Furnace combustion zone temperature control method

A method for controlling temperature in a combustion zone in a furnace, independent of flue gas oxygen content, comprising the steps:

• (a) supplying combustion air to said furnace for combustion of a fuel therein;
• (b) providing a plurality of low volume gas flow entry ports to said combustion zone in said furnace with carrier gas continuously flowing through said ports into said combustion zone;
• (c) selecting a set point value for said combustion zone temperature which, upon said temperature exceeding said set point value, commences generation of a fine water mist external said combustion zone by mist generating means within said carrier gas, said mist flowing into said combustion zone with said carrier gas and reducing temperature within said combustion zone by vaporization therein;
• and
• (d) adding a proportionately greater amount of water mist to said carrier gas as the temperature of said combustion zone deviates above said set point value, said amount of water mist added limited by the capacity of said mist generating means, and ceasing said water mist generation upon said combustion zone temperature falling to or below said set point value.