Pollutant reduction with selective gas stack recirculation

Claim 7

The method set forth in claim 3 wherein: a. the amount of externally recirculated exhaust gas introduced with fuel in the upstream region of said core stream is about 10 to 30 percent the total mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 8

The method set forth in claim 3 including: a. internally recirculating a portion of the hot gaseous combustion products from said upstream region of said core further upstream and in proximity with said fuel to aid in vaporizing and preparing said fuel for combustion.

Claim 9

The method set forth in claim 3 wherein: a. the amount of air introduced with fuel in the upstream regions of said core stream is in the range of about 5 to 15 percent of the total mass flow of stack discharged exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 10

The method set forth in claim 3 wherein: a. the amount of air introduced in said additional air including gas stream for mixing with said core stream as aforesaid is 30 to 50 percent in terms of stack discharged mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 11

The method set forth in claim 3 including the step of: a. passing said gases resulting from the core stream and the air including gas stream through means for producing a pressure drop and, hence, increased gas velocity and turbulence downstream for thereby promoting further mixing and more complete combustion of said gaseous mixture.

Claim 12

The method set forth in claim 3 including: a. introducing a first quantity of air continuously to diffuse and mix with the gaseous combustion products downstream of the region where there is substantial mixing of said additional air and the combustion products of said core stream.

Claim 13

The method set forth in claim 9 wherein: a. the amount of air introduced as said first quantity is about from 0 to 50 percent of the total mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 14

The method set forth in claim 9 including: a. introducing a second quantity of air continuously to diffuse and mix next downstream with the gaseous combustion products resulting from admixture of said first quantity of air.

Claim 15

The method set forth in claim 11 wherein: a. the amount of air introduced as said second quantity of air is about 0 to 50 percent of the stack discharged mass flow of exhaust gases.

Claim 16

The method set forth in claim 3 especially adapted for burning high specific gravity liquid fuels such as No. 6 fuel oil and the like, wherein: a. the amount of exhaust gases introduced with said fuel in the upstream portion of said core stream is more than 25 percent of the stack discharged mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 17

The method set forth in claim 13 wherein: a. the amount of said additional air introduced to mix with said core stream downstream is from 40 to 50 percent of the stack discharged mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 18

The method set forth in claim 13 wherein: a. the amount of air introduced in said core stream along with said fuel and carbon dioxide containing exhaust gas is about 0 to 10 percent of the total mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 19

The method set forth in claim 13 including: a. introducing a first quantity of air continuously to diffuse and mix with the gaseous combustion products downstream of the region where there is substantial mixing of said additional air and the combustion products of said core stream.

Claim 20

The method as set forth in claim 3 wherein: a. said additional air is introduced as a stream surrounding said core stream and flowing confluently therewith.

Claim 21

The method set forth in claim 3 wherein: a. said exhaust gases are introduced into said core stream at a temperature of 60* to 400*C.

Claim 22

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means, said burner means including means for injecting fuel into said zone and means defining passageways for selectively injecting gases selected from the group of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide from an upstream direction of said injecting means and past said injecting means in surrounding relationship therewith and concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core stream for reacting with constituents thereof, and e. means for returning to said first passageway a portion of the carbon dioxide containing gaseous exhaust products resulting from combustion in said zone and exiting therefrom.

Claim 23

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means, said burner means including means for injecting fuel into said zone and means defining passageways for selectively injecting gases selected from the group of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide from an upstream direction of said injecting means and past said injecting means in surrounding relationship therewith and concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core stream for reacting with constituents thereof, and e. means for returning to said first passageway a portion of the carbon dioxide containing gaseous exhaust products resulting from combustion in said zone and exiting therefrom.

Claim 24

The apparatus set forth in claim 19 wherein: a. saiD fuel injecting means comprise nozzle means having orifice means directed to said combustion zone; b. said first one of said passageway defining means comprising diaphragm means having an aperture aligned with said nozzle means, whereby to direct said combustion supporting gas confluently with said finely divided fuel to enable generation of said core stream.

Claim 25

The apparatus set forth in claim 19 wherein: a. said fuel injecting means comprise nozzle means having orifice means directed to said combustion zone, b. said first one of said gas passageway defining means including a cylinder means aligned with said nozzle means and arranged relative to said nozzle means such that fuel and gas including said carbon dioxide may flow confluently therethrough into said combustion zone to form said core stream.

Claim 26

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. said fuel injecting means comprising nozzle means having orifice means directed to said combustion zone, g. said first one of said gas passageway defining means including a cylinder means aligned with said nozzle means and arranged relative to said nozzle means such that fuel and said gas including said carbon dioxide may flow confluently therethrough into said combustion zone to form said core stream, and h. diaphragm means transverse to said cylinder means and having an aperture therein which is aligned with said nozzle means, said aperture admitting said gas including carbon dioxide to said cylinder means for exiting to said combustion zone core stream.

Claim 27

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. said fuel injecting means comprising nozzle means having orifice means directed to said combustion zone, g. said first one of said gas passageway defining means including a cylinder means aligned with said nozzle means and arranged relative to said nozzle means such that fuel and said gas including said carbon dioxide may flow confluently therethrough into said combustion zone to form said core stream, and h. diaphragm means transverse to said cylinder means and having an aperture therein which is aligned with said nozzle means, said aperture admitting said gas including carbon dioxide to said cylinder means for exiting to said combustion zone core stream.

Claim 28

The invention set forth in claim 19 wherein: a. said first and second gas passageway defining means are in communication with each other and with said means for returning said portion of said exhaust gaseous combustion products, b. and means interposed between said gas returning means and passageways for regulating the amount of exhaust gas flowing into said passageways.

Claim 29

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second oNe of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. means interposed in the gaseous combustion product stream near the exit of said combustion zone defining means, said interposed means having a plurality of openings for said gases to flow through to thereby increase velocity and effect mixing of the gases of said core stream and the gases introduced to said combustion zone from said second passageway whereby to enhance oxidation of carbon monoxide resulting from the reaction of carbon and carbon dioxide in said core stream.

Claim 30

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second oNe of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. means interposed in the gaseous combustion product stream near the exit of said combustion zone defining means, said interposed means having a plurality of openings for said gases to flow through to thereby increase velocity and effect mixing of the gases of said core stream and the gases introduced to said combustion zone from said second passageway whereby to enhance oxidation of carbon monoxide resulting from the reaction of carbon and carbon dioxide in said core stream.

Claim 31

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. first grid means comprised of tube means having a plurality of oxygen containing gas exit holes, said first grid means being interposed in the gaseous combustion product stream remotely downstream from said burner means to mix said oxygen containing gas into said stream for burning to carbon dioxide a substantial portion of the carbon monoxide which is produced by the reaction between carbon and carbon dioxide in said core stream.

Claim 32

Apparatus for burning fuel comprised substantially of hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products produced therein, b. burner means coupled with said combustion zone defining means including means for injecting fuel into said zone and means for defining passageways for selectively injecting gases selected from the group consisting of carbon dioxide containing gaseous combustion products and air and mixtures thereof into said zone concurrently with said fuel, c. at least a first one of said gas passageway defining means being for flowing gas including carbon dioxide concurrently with said fuel to effect an ignited core stream for progressing through said combustion zone, d. a second one of said gas passageways being for introducing at least one of said gases into said combustion zone contiguous with said core for reacting with constituents thereof, e. means for returning to said first passageway a portion of the gaseous exhaust products containing carbon dioxide resulting from combustion in said zone and exiting therefrom, f. first grid means comprised of tube means having a plurality of oxygen containing gas exit holes, said first grid means being interposed in the gaseous combustion product stream remotely downstream from said burner means to mix said oxygen containing gas into said stream for burning to carbon dioxide a substantial portion of the carbon monoxide which is produced by the reaction between carbon and carbon dioxide in said core stream.

Claim 33

Apparatus for burning fuel comprising substantially hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products formed therein, b. burner means in communication with said combustion zone in its upstream region, said burner means including nozzle means for injecting finely divided fuel in a downstream direction into said combustion zone, c. means having an aperture transverse to the path of fuel emitted from said nozzle, d. a source of combustion supporting air, e. a source of carbon dioxide containing exhaust gases resulting from fuel combustion in said zone, f. means for controlling the amounts of air and exhaust gases flowing from said sources through said aperture so that said fuel and gases and air react to form an ignited core stream which is rich in fuel and has less than the amount of air for complete combustion of said fuel, whereby the gaseous combustion products resulting in at least the upstream region of said core comprise substantial amounts of carbon particulates with which said carbon dioxide will react to form substantial amounts of carbon monoxide, and g. means for mixing additional air into the gaseous combustion products of said core downstream where said core becomes less defined to promote combustion of said carbon monoxide.

Claim 34

Apparatus for burning fuel comprising substantially hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products formed therein, b. burner means in communication with said combustion zone in its upstream region, said burner means including nozzle means for injecting finely divided fuel in a downstream direction into said combustion zone, c. means having an aperture transverse to the path of fuel emitted from said nozzle, d. a source of combustion supporting air, e. a source of carbon dioxide containing exhaust gases resulting from fuel combustion in said zone, f. means for controlling the amounts of air and exhaust gases flowing from said sources through said aperture so that said fuel and gases and air react to form an ignited core stream which is rich in fuel and has less than the amount of air for complete combustion of said fuel, whereby the gaseous combustion products resulting in at least the upstream region of said core comprise substantial amounts of carbon particulates with which said carbon dioxide will react to form substantial amounts of carbon monoxide, and g. means for mixing additional air into the gaseous combustion products of said core downstream where said core becomes less defined to promote combustion of said carbon monoxide.

Claim 35

Apparatus for burning fuel comprising substantially Hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products formed therein, b. burner means coupled with said combustion zone in its upstream region, said burner means including nozzle means for injecting finely divided fuel in a downstream direction into said combustion zone, c. first means constructed and arranged for directing combustion supporting gases in a generally downstream direction and in surrounding relationship in respect to said nozzle means, d. second means for conducting to said first means less than the amount of oxygen containing air required for stoichiometric combustion of said fuel such that the combustion products in an upstream region of said combustion zone resulting from reaction of said air with said fuel will comprise completely and incompletely oxidized combustion products including particulate carbon, e. third means for conducting carbon dioxide containing gaseous combustion products from said combustion zone to said first means for said gaseous combustion products to flow with said air and for the carbon dioxide therein to react with said carbon in said upstream region to produce carbon monoxide in said combustion zone, and f. means constructed and arranged for introducing additional air into said combustion zone separately from said gases and said fuel for said additional air to react with a substantial amount of said carbon monoxide to thereby yield carbon dioxide.

Claim 36

Apparatus for burning fuel comprising substantially Hydrocarbons to obtain low levels of nitrogen oxides, carbon monoxide and unburned substances in the exhaust gases therefrom, comprising: a. means defining a combustion zone having an exit for gaseous combustion products formed therein, b. burner means coupled with said combustion zone in its upstream region, said burner means including nozzle means for injecting finely divided fuel in a downstream direction into said combustion zone, c. first means constructed and arranged for directing combustion supporting gases in a generally downstream direction and in surrounding relationship in respect to said nozzle means, d. second means for conducting to said first means less than the amount of oxygen containing air required for stoichiometric combustion of said fuel such that the combustion products in an upstream region of said combustion zone resulting from reaction of said air with said fuel will comprise completely and incompletely oxidized combustion products including particulate carbon, e. third means for conducting carbon dioxide containing gaseous combustion products from said combustion zone to said first means for said gaseous combustion products to flow with said air and for the carbon dioxide therein to react with said carbon in said upstream region to produce carbon monoxide in said combustion zone, and f. means constructed and arranged for introducing additional air into said combustion zone separately from said gases and said fuel for said additional air to react with a substantial amount of said carbon monoxide to thereby yield carbon dioxide.

Claim 37

The apparatus set forth in claim 27 wherein: a. said first means comprises a chamber for receiving said less than the stoichiometric amount of air and said carbon dioxide containing gas, b. means in said chamber having an aperture for said directing of said gaseous mixture, said nozzle means being aligned with said aperture for projecting said fuel substantially centrally thereof.

Claim 40

The method set forth in claim 29 wherein: a. the additional air quantity provided is substantially the difference between the amount of air required for complete combustion of the fuel and the amount introduced with said fuel to form said flame core.

Claim 41

The method set forth in claim 29 wherein: a. the quantity of exhaust gas introduced with said fuel is about 10 to 30 percent of the total mass flow of exhaust gases resulting from burning said fuel under the conditions set forth.

Claim 42

The method set forth in claim 29 including: a. flowing the gaseous combustion products produced in said combustion zone through means for producing a pressure drop to thereby increase the velocity of said products and the turbulence thereof for promoting their mixing and, hence, more complete combustion.