# US 5,213,492 A · Combustion method for simultaneous control of nitrogen oxides and products of incomplete combustion

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- Number: US 5,213,492 A
- Document ID: US5213492A
- Status: Granted
- Kind: A
- Application number: 07/830,774
- Filed: 1992-02-06
- Granted: 1993-05-25
- Earliest claimed: 1991-02-11
- Assignees: Praxair Technology, Inc.
- Inventors: Min-Da Ho
- Web page: https://patentgrep.com/patent/US5213492A

## CPC

- F23L 7/00: Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
- F23G 5/16: in a separate combustion chamber
- F23N 1/022: {using electronic means}
- F23N 5/003: {using detectors sensitive to combustion gas properties (F23N5/02, F23N5/18 - F23N5/26 take precedence)}
- F23C 2900/06041: Staged supply of oxidant
- F23C 2900/09002: Specific devices inducing or forcing flue gas recirculation
- F23G 2202/101: with controlled oxidant supply
- F23G 2202/102: with supplementary heating
- F23G 2207/103: for oxygen
- F23G 2209/12: Sludge, slurries or mixtures of liquids
- F23G 2209/24: Contaminated soil; foundry sand
- F23G 2900/52001: Rotary drums with co-current flows of waste and gas
- F23L 2900/07005: Injecting pure oxygen or oxygen enriched air
- F23L 2900/07006: Control of the oxygen supply
- F23L 2900/07008: Injection of water into the combustion chamber
- F23N 2237/16: secondary air
- Y02E 20/34: Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
- F23L: SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ({air-supply arrangements for fluent fuels F23C;} firebridges with means for feeding air or steam F23M3/04; baffles or shields with air supply passages F23M9/04); VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS {(dampers and throat restrictors for open fire-places F24; air inlet valves for open fire fronts F24)}; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23G: CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23N: REGULATING OR CONTROLLING COMBUSTION (control devices specially adapted for combustion apparatus in which combustion takes place in a fluidised bed of fuel or other particles F23C10/28; condition responsive controls for regulating combustion in domestic stoves with open fires for solid fuel F24B1/187)
- F23C: METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN {A CARRIER GAS OR} AIR (burners F23D)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A combustion method for the simultaneous control of PICs and NO.sub.x wherein the combustion is carried out in two combustion zones. High velocity oxidant is injected into the second combustion zone to aspirate exhaust from the first combustion zone prior to combustion within the second combustion zone. The first combustion zone is preferably operated under pyrolytic conditions.

## Claims

### Claim 1

A method for combusting material with controlled generation of both nitrogen oxides and products of incomplete combustion comprising:
(A) combusting material in a first combustion zone to produce gaseous exhaust containing products of incomplete combustion and products of complete combustion;
(B) passing the gaseous exhaust from the first combustion zone into a second combustion zone having a width and an axial direction;
(C) injecting through a lance with an orientation substantially parallel to said axial direction at least one stream of oxidant, without fuel, having a diameter less than 1/100 of the width of the second combustion zone and having an oxygen concentration of at least 30 percent into the second combustion zone at a high velocity of at least 300 feet per second;
(D) aspirating products of incomplete combustion into the high velocity oxidant;
(E) combusting products of incomplete combustion aspirated into the high velocity oxidant with high velocity oxidant within the second combustion zone to carry out a stable combustion by the mixing of the aspirated products of incomplete combustion with the high velocity oxidant; and
(F) spreading out the combustion reaction by aspiration of products of complete combustion into the oxidant, said products of complete combustion also serving as a heat sink, to inhibit NO.sub.x formation.

### Claim 2 (depends on 1)

The method of claim 1 wherein the high velocity oxidant is injected in a plurality of streams.

### Claim 3 (depends on 1)

The method of claim 1 wherein the high velocity oxidant is technically pure oxygen.

### Claim 4 (depends on 1)

The method of claim 1 further comprising the aspiration of coolant into the high velocity oxidant.

### Claim 5 (depends on 4)

The method of claim 4 wherein the coolant is atomized water.

### Claim 6 (depends on 1)

The method of claim 1 wherein aspiration of products of incomplete combustion and products of complete combustion into the high velocity oxidant occurs within the second combustion zone.

### Claim 7 (depends on 1)

The method of claim 1 wherein combustion within the first combustion zone is carried out under pyrolytic conditions.

### Claim 8 (depends on 1)

The method of claim 1 wherein the combustion within the second combustion zone is carried out under oxidative conditions.

### Claim 9 (depends on 1)

The method of claim 1 wherein the combustion within the first combustion zone is carried out under pyrolytic conditions and the combustion within the second combustion zone is carried out under oxidative conditions.

### Claim 10 (depends on 1)

The method of claim 1 wherein the level of oxygen within the second combustion zone is maintained at a desired level by monitoring the level of oxygen within the second combustion zone or within the effluent passed out from the second combustion zone and increasing the flow of high velocity oxidant into the second combustion zone when the level of oxygen within the effluent falls below a predetermined level.

### Claim 11 (depends on 1)

The method of claim 1 wherein the level of oxygen within the second combustion zone is maintained at a desired level by monitoring the level of carbon monoxide within the second combustion zone or within the effluent passed out from the second combustion zone and increasing the flow of high velocity oxidant into the second combustion zone when the level of carbon monoxide within the second combustion zone or effluent exceeds a predetermined level.