Combustion method for low velocity reactant streams

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.

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.

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.

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.