Reduction of pollutants in gaseous hydrocarbon combustion products

Claim 1

A METHOD OF BURNING FUEL IN A MANNER TO REDUCE THE NITROGEN OXIDES, CARBON MONOXIDE, AND UNBURNED HYDROCARBONS AND CARBONACEOUS PARTICULATES IN THE EXHAUST GASES THEREFROM, COMPRISING: A. DEVELOPING IN A CONTINUOUS COMBUSTION ZONE IN IGNITED CORE STREAM CONSTITUTING A FUEL-RICH MIXTURE OF FUEL AND SUBSTANTIALLY LESS THAN THE AMOUNT OF AIR REQUIRED FOR STOICHIOMETRIC COMBUSTION, B. INTRODUCING INTO SAID CONTINUOUS COMBUSTION ZONE A SHEATH OF AIR WHICH SURROUNDS AND INTERFACES DIRECTLY WITH SAID CORE STREAM AND WHICH FLOWS THEREALONG WITHOUT DISCONTINUITY, THE QUANTITY OF AIR INTRODUCED AS SAID SHEATH BEING AT LEAST THE ENTIRE QUANTITY OF ADDITIONAO L AIR AND NOT SUBSTANTIALLY MORE THAN THE ADDITIONAL AIR REQUIRED TO MAKE UP THE STOICHIOMETRIC AMOUNT OF FOR COMPLETE COMBUSTION OF SAID FUEL, C. PASSING SAID SHEATH IN A HEAT EXCHANGE RELATION WITH COOLING MEANS FOR EXTRACTING SOME HEAT PERMANENTLY FROM SAID CORE STREAM, AND THEN D. ALLOWING THE INCOMPLETELY OXIDIZED GASEOUS COMBUSTION PRODUCTS AND SAID SHEATH AIR TO MIX IN NON-DISCRETE STAGES IN SAID COMBUSTION ZONE AND EFFECT FURTHER COMBUSTION OF SOME OF THE THERETOFORE INCOMPLETELY OXIDIZED COMPONENTS OF SAID FUEL AT A LOW ENOUGH TEMPERATURE TO AVOID PRODUCTION OF SUBSTANTIAL QUANTITIES OF NITROGEN OXIDES.

Claim 2

A METHOD OF BURNING FUEL IN A MANNER TO REDUCE THE NITROGEN OXIDES, CARBON MONOXIDE, AND UNBURNED HYDROCARBONS AND CARBONACEOUS PARTICULATES IN THE EXHAUST GASES THEREFROM, COMPRISING: A. DEVELOPING IN A CONTINUOUS COMBUSTION ZONE IN IGNITED CORE STREAM CONSTITUTING A FUEL-RICH MIXTURE OF FUEL AND SUBSTANTIALLY LESS THAN THE AMOUNT OF AIR REQUIRED FOR STOICHIOMETRIC COMBUSTION, B. INTRODUCING INTO SAID CONTINUOUS COMBUSTION ZONE A SHEATH OF AIR WHICH SURROUNDS AND INTERFACES DIRECTLY WITH SAID CORE STREAM AND WHICH FLOWS THEREALONG WITHOUT DISCONTINUITY, THE QUANTITY OF AIR INTRODUCED AS SAID SHEATH BEING AT LEAST THE ENTIRE QUANTITY OF ADDITIONAO L AIR AND NOT SUBSTANTIALLY MORE THAN THE ADDITIONAL AIR REQUIRED TO MAKE UP THE STOICHIOMETRIC AMOUNT OF FOR COMPLETE COMBUSTION OF SAID FUEL, C. PASSING SAID SHEATH IN A HEAT EXCHANGE RELATION WITH COOLING MEANS FOR EXTRACTING SOME HEAT PERMANENTLY FROM SAID CORE STREAM, AND THEN D. ALLOWING THE INCOMPLETELY OXIDIZED GASEOUS COMBUSTION PRODUCTS AND SAID SHEATH AIR TO MIX IN NON-DISCRETE STAGES IN SAID COMBUSTION ZONE AND EFFECT FURTHER COMBUSTION OF SOME OF THE THERETOFORE INCOMPLETELY OXIDIZED COMPONENTS OF SAID FUEL AT A LOW ENOUGH TEMPERATURE TO AVOID PRODUCTION OF SUBSTANTIAL QUANTITIES OF NITROGEN OXIDES.

Claim 15

A method of burning fuel in a manner to reduce nitrogen oxides, carbon monoxide, unburned hydrocarbons and carbonaceous particulates in the exhaust gases therefrom, comprising: a. injecting into a continuous combustion zone fuel and substantially less than the amount of air required for stoichiometric combustion of said fuel to produce an ignited fuel-rich core stream directed from the input upstream end generally toward the output downstream end of said combustion zone, and b. flowing into said continuous combustion zone in direct contact with said core stream from said input end toward said output end additional air to sheath said core stream and progressively intermix therewith in non-discrete stages while at the same time absorbing heat from said sheath air and said mixture with cooling means that dissipate said heat permanently to heat absorbing means outside of said combustion zone and other than to air that is introduced to said zone, the quantity of said additional air being at least equal to and not substantially greater than that required to make up the stoichiometric amount for complete combustion of all of the injected fuel.

Claim 16

A method of burning fuel in a manner to reduce nitrogen oxides, carbon monoxide, unburned hydrocarbons and carbonaceous particulates in the exhaust gases therefrom, comprising: a. injecting into a continuous combustion zone fuel and substantially less than the amount of air required for stoichiometric combustion of said fuel to produce an ignited fuel-rich core stream directed from the input upstream end generally toward the output downstream end of said combustion zone, and b. flowing into said continuous combustion zone in direct contact with said core stream from said input end toward said output end additional air to sheath said core stream and progressively intermix therewith in non-discrete stages while at the same time absorbing heat from said sheath air and said mixture with cooling means that dissipate said heat permanently to heat absorbing means outside of said combustion zone and other than to air that is introduced to said zone, the quantity of said additional air being at least equal to and not substantially greater than that required to make up the stoichiometric amount for complete combustion of all of the injected fuel.

Claim 17

A method of burning non-solid fuel characterized by the steps of: a. projecting into a combustion zone fuel and air for forming an ignited core stream that is propagated in an axial direction in said zone, the amount of air admitted with the fuel being substantailly less than that required for stoichiometric combustion of the fuel, b. flowing additional air into said zone from the input end in surrounding relationship to the core stream initially and intermixing said core stream and air in non-discrete stages and in a continuous and progressive manner by mutually generally radially outward movement of the core stream gaseous products and generally inward movement of said additional air as the gaseous core stream products and air progress in the axial direction of the combustion zone, the quantity of additional air being at least equal to but not substantially greater than the air required to make up the quantity for stoichiometric combustion of the fuel, and c. transferring heat from at least the radially outward portions of the gases flowing in said combustion zone to heat absorbing means extending from near said input end of said zone to a substantial distance in the axial direction from said input end, said absorbing means extracting heat permanently from said combustion zone whereby the temperature of the gases in said combustion zone is maintained below that at which substantial quantities of nitrogen oxides are produced.

Claim 18

A method of burning non-solid fuel characterized by the steps of: a. projecting into a combustion zone fuel and air for forming an ignited core stream that is propagated in an axial direction in said zone, the amount of air admitted with the fuel being substantailly less than that required for stoichiometric combustion of the fuel, b. flowing additional air into said zone from the input end in surrounding relationship to the core stream initially and intermixing said core stream and air in non-discrete stages and in a continuous and progressive manner by mutually generally radially outward movement of the core stream gaseous products and generally inward movement of said additional air as the gaseous core stream products and air progress in the axial direction of the combustion zone, the quantity of additional air being at least equal to but not substantially greater than the air required to make up the quantity for stoichiometric combustion of the fuel, and c. transferring heat from at least the radially outward portions of the gases flowing in said combustion zone to heat absorbing means extending from near said input end of said zone to a substantial distance in the axial direction from said input end, said absorbing means extracting heat permanently from said combustion zone whereby the temperature of the gases in said combustion zone is maintained below that at which substantial quantities of nitrogen oxides are produced.

Claim 21

A method of burning fuel in a manner to reduce the nitrogen oxides, carbon monoxide, and unburned hydrocarbons and carbonaceous particulates in the exhaust gases therefrom, comprising: a. developing in a continuous combustion zone an ignited core stream constituting a fuel-rich mixture of fuel and substantially less than the amount of air required for stoichiometric combustion, b. introducing into said continuous combustion zone a sheath of air which surrounds and interfaces directly with said core stream and which flows therealong without discontinuity, the quantity of air introduced as said sheath being at least the entire quantity of additional air and not substantially more than the additional air required to maKe up the stoichiometric amount for complete combustion of said fuel, c. passing said sheath in a heat exchange relation with cooling means for extracting some heat permanently from said core stream, and then d. allowing the incompletely oxidized gaseous combustion products and said sheath air to mix in non-discrete stages in said combustion zone and effect further combustion of some of the theretofore incompletely oxidized components of said fuel at a low enough temperature to avoid production of substantial quantities of nitrogen oxides, and e. increasing the velocity of said mixture to promote turbulence and more complete mixing thereof whereby to enhance oxidation of residual combustibles other than nitrogen.

Claim 22

A method of burning fuel in a manner to reduce the nitrogen oxides, carbon monoxide, and unburned hydrocarbons and carbonaceous particulates in the exhaust gases therefrom, comprising: a. developing in a continuous combustion zone an ignited core stream constituting a fuel-rich mixture of fuel and substantially less than the amount of air required for stoichiometric combustion, b. introducing into said continuous combustion zone a sheath of air which surrounds and interfaces directly with said core stream and which flows therealong without discontinuity, the quantity of air introduced as said sheath being at least the entire quantity of additional air and not substantially more than the additional air required to maKe up the stoichiometric amount for complete combustion of said fuel, c. passing said sheath in a heat exchange relation with cooling means for extracting some heat permanently from said core stream, and then d. allowing the incompletely oxidized gaseous combustion products and said sheath air to mix in non-discrete stages in said combustion zone and effect further combustion of some of the theretofore incompletely oxidized components of said fuel at a low enough temperature to avoid production of substantial quantities of nitrogen oxides, and e. increasing the velocity of said mixture to promote turbulence and more complete mixing thereof whereby to enhance oxidation of residual combustibles other than nitrogen.