Enhanced combustion of hydrocarbonaceous burner fuels

A method for improving the efficiency of combustion in a burner that employs as its fuel hydrocarbonaceous middle distillate fuel and for reducing at least the quantity of carbon monoxide emissions from such burner during operation of said burner, which method comprises:

• a) continuously feeding into the combustion zone of the burner when combustion is occurring therein, hydrocarbonaceous middle distillate fuel with which has been blended concurrently and/or in any sequence and/or in any preformed combination and/or preformed subcombination thereof, at least the following ingredients:
• a minor combustion improving amount of (i) at least one fuel-soluble manganese polycarbonyl compound, (ii) at least one overbased alkali or alkaline earth metal-containing detergent, and (iii) at least one fuel-soluble dispersant;
• b) continuously feeding into the combustion zone of the burner when combustion is occurring therein, an amount of air that is sufficient to support combustion of the fuel being fed into said zone;
• and
• c) maintaining the proportions of the fuel blend of a) and the air of b) being fed into said combustion zone such that the air-to-fuel ratio is continuously at least about 0.7 percent above the stoichiometric amount required for complete combustion of said fuel being fed into said zone, but below 5 percent above the stoichiometric amount of air required for complete combustion of said fuel being fed into said zone, wherein compound (i) is present in an amount sufficient to provide at least about 0.5 milligram of manganese per gallon (U.S.) of fuel.