Combustion method for low velocity reactant streams

Abstract

A combustion method in which heated flue gas heats a regenerator through which a mixture of fuel and flue gas is then passed to undergo endothermic reactions that produce syngas which is fed into a furnace together with a motive gas stream.

1 . A method of carrying out combustion in a furnace, comprising
 (i) passing fuel gas at a velocity less than 50 feet per second into a duct having an outlet that is connected to the interior of the furnace,   (ii) injecting at least one stream of motive gas having a velocity of at least 200 feet per second into the fuel gas in the duct wherein the mass flow rate of the motive gas injected into the fuel gas is less than 60% of the mass flow rate of the fuel gas into which the motive gas is injected,   (iii) forming in the duct at least one mixed stream comprising a mixture of the fuel gas and the motive gas and having a momentum average velocity greater than 50 feet per second in the direction of said outlet,   (iv) passing said mixed stream from said duct into said furnace, and   (v) combusting the mixed stream with one or more oxidant streams injected into said furnace.   
     
     
         2 .- 4 . (canceled) 
     
     
         5 . A method according to  claim 1  wherein the motive gas is injected into the fuel gas from a nozzle having an internal diameter D in the duct at an upstream distance L from the interior wall of the furnace under conditions such that the value of (L/D)×(N/R) is from 4 to 25, wherein N is the number of streams of motive gas injected into the fuel gas in the duct and R is the ratio of the total mass flow rate of fuel gas passed into the duct to the total mass flow rate of the stream, or all of the streams, of motive gas injected into the duct, thereby entraining the fuel gas into the motive gas stream in the duct and forming in the duct at least one mixed stream comprising a mixture of the fuel gas and the motive gas and having a velocity greater than 50 feet per second. 
     
     
         6 . (canceled) 
     
     
         7 . A method according to  claim 1  wherein at least two streams of motive gas are injected at a velocity of at least 200 feet per second in a diverging angle relative to each other in the horizontal direction into the fuel gas in the duct toward the said outlet and the mass flow rate of each stream of the motive gas injected into the fuel gas is less than 10% of the mass flow rate of the fuel gas into which the motive gas is injected. 
     
     
         8 . (canceled) 
     
     
         9 . A method of carrying out combustion in a furnace equipped with thermochemical regenerators with a firing port through which heated syngas can enter the furnace, one or more oxidant ports through which oxidant can be injected into the furnace, and an exhaust port which is connected to the furnace and through which gaseous combustion products can exit from the furnace, comprising
 (i) flowing heated syngas through the firing port into the furnace at momentum F at a velocity less than 50 feet per second,   (ii) injecting at least one stream of motive gas at momentum M having a velocity of at least 100 feet per second, inside the firing port to entrain said syngas into the motive gas stream and to project the resulting combined stream into the furnace,   (iii) injecting one or more streams of oxidant at total momentum O through said one or more oxidant ports into the furnace wherein the axis of each stream of oxidant is placed between 3 inches to 30 inches from the interior perimeter of the firing port, and mixing the injected oxidant with the fuel stream that is entrained into the motive gas stream to form a visible flame projecting into the furnace without touching walls nor crown of the furnace, and   (iv) exhausting gaseous combustion products from the furnace through the exhaust port at momentum X, wherein the combined momentum F+M+O is greater than 150% of the momentum X.   
     
     
         10 . A method according to  claim 9 , wherein the combined momentum F+M+O is greater than 300% of the momentum X. 
     
     
         11 . A method according to  claim 9 , wherein said momentum M is greater than the momentum X. 
     
     
         12 . (canceled) 
     
     
         13 . A method according to  claim 9 , wherein said motive gas comprises 5 to 20% of the total oxidant flow injected into said furnace. 
     
     
         14 . A method according to  claim 9 , wherein said streams of oxidant are injected at velocity greater than 100 ft/sec. 
     
     
         15 .- 17 . (canceled) 
     
     
         18 . A method according to  claim 9  wherein at least two streams of motive gas are injected into said heated syngas in each firing port in a diverging angle to each other in the horizontal direction so as to form a horizontally wide visible flame. 
     
     
         19 . (canceled) 
     
     
         20 . A method of carrying out combustion in a furnace equipped with thermochemical regenerators with a firing port through which heated syngas can enter the furnace, one or more oxidant ports through which oxidant can be injected into the furnace, and an exhaust port which is connected to the furnace and through which gaseous combustion products can exit from the furnace, comprising
 (i) flowing heated syngas through the firing port into the furnace at momentum F at a velocity less than 50 feet per second,   (ii) injecting at least one stream of motive gas at momentum M having a velocity of at least 100 feet per second and one or more streams of oxidant into the furnace at total oxidant momentum O from points in a wall outside the firing port wherein the axis of each stream of motive gas and oxidant is placed between 3 inches to 30 inches from the interior perimeter of the firing port, and entraining surrounding furnace gas and syngas to form a visible flame projecting into the furnace without touching walls nor crown of the furnace, and   (iii) exhausting gaseous combustion products from the furnace through the exhaust port at momentum X, wherein the combined momentum F+M+O is greater than 150% of the momentum X.   
     
     
         21 . A method according to  claim 20 , wherein the combined momentum F+M+O is greater than 300% of the momentum X. 
     
     
         22 . (canceled) 
     
     
         23 . A method according to  claim 20 , wherein said streams of oxidant are injected at velocity greater than 100 ft/sec. 
     
     
         24 . A method according to  claim 20 , wherein at least one of said streams of oxidant are injected from above the firing port. 
     
     
         25 .- 27 . (canceled) 
     
     
         28 . A method according to  claim 20  wherein at least two streams of motive gas are injected into said heated syngas in each firing port in a diverging angle to each other in the horizontal direction so as to form a horizontally wide visible flame. 
     
     
         29 . (canceled) 
     
     
         30 . A method of carrying out combustion in a furnace, comprising
 (i) passing fuel gas at a velocity less than 50 feet per second into a duct having an outlet that is connected to the interior of the furnace,   (ii) injecting at least one stream of motive gas having a velocity of at least 100 feet per second into the fuel gas in the duct in the direction of said outlet, wherein the mass flow rate of the motive gas injected into the fuel gas is less than 60% of the mass flow rate of the fuel gas into which the motive gas is injected,   (iii) entraining at least 50 vol. % of the fuel gas into the motive gas stream to thereby form in the duct at least one mixed stream comprising a mixture of the fuel gas and the motive gas and having a velocity greater than 50 feet per second,   (iv) passing said mixed stream at a velocity of greater than 50 feet per second from said duct into said furnace, and   (v) combusting the mixed stream with one or more oxidant streams injected into said furnace.   
     
     
         31 . A method of carrying out combustion in a furnace, comprising
 (i) passing fuel gas which is syngas from a thermo-chemical regenerator at a velocity less than 50 feet per second into a duct having an outlet that is connected to the interior of the furnace,   (ii) injecting at least one stream of motive gas having a velocity of at least 100 feet per second from a nozzle in the duct having an internal diameter D into the syngas in the duct at an upstream distance L from the interior wall of the furnace wherein the mass flow rate of the motive gas injected into the fuel gas is less than 60% of the mass flow rate of the fuel gas into which the motive gas is injected,   (iii) under conditions such that the value of (L/D)×(N/R) is from 4 to 25, wherein N is the number of streams of motive gas injected into the syngas in the duct and R is the ratio of the total mass flow rate of syngas passed into the duct to the total mass flow rate of the stream, or all of the streams, of motive gas injected into the duct, thereby entraining the syngas into the motive gas stream in the duct and forming in the duct at least one mixed stream comprising a mixture of the syngas and the motive gas and having a velocity greater than 50 feet per second,   (iv) passing said mixed stream at a velocity of greater than 50 feet per second from said duct into said furnace, and   (v) combusting the mixed stream with one or more oxidant streams injected into said furnace.   
     
     
         32 . (canceled) 
     
     
         33 . A method according to  claim 30  wherein said motive gas has an oxygen content of at least 75 vol. % oxygen. 
     
     
         34 . A method according to  claim 30  wherein the oxygen content of the mixture of motive gas and fuel gas is less than the stoichiometric requirement for complete combustion of the fuel gas in the mixture, and wherein one or more secondary streams of gaseous oxidant comprising oxygen is injected into the furnace to combust with the remainder of the fuel gas in the mixture. 
     
     
         35 .- 36 . (canceled) 
     
     
         37 . A method according to  claim 30  wherein said fuel gas is combusted in said furnace with oxidant comprising at least 75 vol. % oxygen. 
     
     
         38 . (canceled) 
     
     
         39 . A method according to  claim 30  wherein said at least one stream of motive gas injected into the fuel stream in the duct has a velocity of at least 400 feet per second. 
     
     
         40 .- 41 . (canceled) 
     
     
         42 . A method according to  claim 30  wherein the motive gas comprises oxygen and the mass flow rate of the motive gas injected into the fuel gas provides between 5% to 35% of the stoichiometric mass flow rate of oxygen required for complete combustion of the fuel gas into which the motive gas is injected. 
     
     
         43 . A method according to  claim 30  wherein said mixed stream is passed from said duct into said furnace at a velocity greater than 100 feet per second. 
     
     
         44 .- 46 . (canceled) 
     
     
         47 . A method according to  claim 30  wherein said combustion of the mixed stream with one or more oxidant streams injected into said furnace forms a flame that does not visibly touch the interior walls or ceiling in the furnace. 
     
     
         48 . A method of carrying out combustion in a furnace, comprising
 (A) combusting fuel in a furnace to produce gaseous combustion products; and   (B) alternately
 (1) (i) passing a portion of the gaseous combustion products into and through a cooled first regenerator to heat the first regenerator and cool said portion of the gaseous combustion products, 
   (ii) passing at least part of said cooled portion of gaseous combustion products from said first regenerator, and fuel, into a heated second regenerator and, in the second regenerator, reacting the gaseous combustion products and the fuel in an endothermic reaction in the second regenerator to form syngas comprising hydrogen and CO,   (iii) passing said syngas formed in the second regenerator at a velocity less than 50 feet per second into a first duct having an outlet that is connected to the interior of the furnace,   (iv) injecting at least one stream of motive gas having a velocity of at least 100 feet per second from a nozzle in the first duct having an internal diameter D into the syngas in the first duct at an upstream distance L from the interior wall of the furnace wherein the mass flow rate of the motive gas injected into the syngas is less than 60% of the mass flow rate of the syngas into which the motive gas is injected,
 under conditions such that the value of (L/D)×(N/R) is from 4 to 25, wherein N is the number of streams of motive gas injected into the syngas in the first duct and R is the ratio of the total mass flow rate of syngas passed into the first duct to the total mass flow rate of the stream, or all of the streams, of motive gas injected into the first duct, thereby entraining the syngas into the motive gas stream in the first duct and forming in the first duct at least one mixed stream comprising a mixture of the syngas and the motive gas and having a velocity greater than 50 feet per second, and 
   (v) passing said mixed stream at a velocity of greater than 50 feet per second from said first duct into said furnace and combusting the mixed stream with one or more oxidant streams injected into said furnace; and
 (2) (i) passing a portion of the gaseous combustion products into and through a cooled second regenerator to heat the second regenerator and cool said portion of the gaseous combustion products, 
   (ii) passing at least part of said cooled portion of gaseous combustion products from said second regenerator, and fuel, into a heated first regenerator and, in the first regenerator, reacting the gaseous combustion products and the fuel in an endothermic reaction in the first regenerator to form syngas comprising hydrogen and CO,   (iii) passing said syngas formed in the first regenerator at a velocity less than 50 feet per second into a second duct having an outlet that is connected to the interior of the furnace,   (iv) injecting at least one stream of motive gas having a velocity of at least 100 feet per second from a nozzle in the duct having an internal diameter D into the syngas in the second duct at an upstream distance L from the interior wall of the furnace wherein the mass flow rate of the motive gas injected into the syngas is less than 60% of the mass flow rate of the syngas into which the motive gas is injected,   under conditions such that the value of (L/D)×(N/R) is from 4 to 25, wherein N is the number of streams of motive gas injected into the syngas in the second duct and R is the ratio of the total mass flow rate of syngas passed into the second duct to the total mass flow rate of the stream, or all of the streams, of motive gas injected into the second duct, thereby entraining the syngas into the motive gas stream in the second duct and forming in the second duct at least one mixed stream comprising a mixture of the syngas and the motive gas and having a velocity greater than 50 feet per second, and   (v) passing said mixed stream at a velocity of greater than 50 feet per second from said second duct into said furnace and combusting the mixed stream with one or more oxidant streams injected into said furnace.   
     
     
         49 . (canceled) 
     
     
         50 . A method according to  claim 49  wherein said motive gas has an oxygen content of at least 75 vol. % oxygen. 
     
     
         51 . A method according to  claim 49  wherein the oxygen content of the mixture of motive gas and syngas is less than the stoichiometric requirement for complete combustion of the syngas in the mixture, and wherein one or more secondary streams of gaseous oxidant comprising oxygen is injected into the furnace to combust with the remainder of the syngas in the mixture. 
     
     
         52 .- 53 . (canceled) 
     
     
         54 . A method according to  claim 48  wherein said fuel and said syngas are combusted in said furnace with oxidant comprising at least 75 vol. % oxygen. 
     
     
         55 . (canceled) 
     
     
         56 . A method according to  claim 48  wherein said at least one stream of motive gas injected into the syngas in the first duct has a velocity of at least 400 feet per second and said at least one stream of motive gas injected into the syngas in the second duct has a velocity of at least 400 feet per second. 
     
     
         57 .- 58 . (canceled) 
     
     
         59 . A method according to  claim 48  wherein the motive gas injected into the first duct and into the second duct comprises oxygen and the mass flow rate of the motive gas injected into the syngas in each duct provides between 5% to 35% of the stoichiometric mass flow rate of oxygen required for complete combustion of the syngas into which the motive gas is injected. 
     
     
         60 . A method according to  claim 48  wherein said mixed stream passed from said first duct into said furnace and said mixed stream passed from said second duct into said furnace are passed at a velocity greater than 100 feet per second. 
     
     
         61 .- 63 . (canceled) 
     
     
         64 . A method according to  claim 48  wherein said combustion of the mixed stream with one or more oxidant streams injected into said furnace forms a flame that does not visibly touch the interior walls or ceiling in the furnace.