Thermochemical regeneration with soot formation

Abstract

Operation of a thermochemical regenerator to generate soot or to increase the amount of soot generated improves the performance of a furnace with which the thermochemical regenerator is operated.

What is claimed is: 
     
         1 . 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 gaseous combustion products from the furnace into and through a cooled first regenerator to heat the first regenerator and cool said gaseous combustion products,   (ii) passing at least a portion of said cooled portion of gaseous combustion products from said first regenerator, and hydrocarbon fuel, into a heated second regenerator,   (iii) reacting the gaseous combustion products and the fuel in the second regenerator in an endothermic reaction under conditions effective to form syngas comprising hydrogen and carbon monoxide and to form soot which is entrained in the syngas, and thereby cooling the second regenerator; and   (iv) passing said syngas and entrained soot from said second regenerator into said furnace and combusting the syngas and entrained soot in the furnace with one or more oxidant streams injected into said furnace; and
 (2) (i) passing a portion of the gaseous combustion products from the furnace 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 a portion of said cooled portion of gaseous combustion products from said second regenerator, and hydrocarbon fuel, into a heated first regenerator,   (iii) reacting the gaseous combustion products and the fuel in the first regenerator in an endothermic reaction under conditions effective to form syngas comprising hydrogen and carbon monoxide and to form soot which is entrained in the syngas, and thereby cooling the first regenerator, and   (iv) passing said syngas and entrained soot from said first regenerator into said furnace and combusting the syngas and entrained soot in the furnace with one or more oxidant streams injected into said furnace.   
     
     
         2 . A method of carrying out combustion in a furnace, comprising
 (A) combusting fuel in a furnace to produce gaseous combustion products,   (B) passing at least a portion of the gaseous combustion products from the furnace, and hydrocarbon fuel, into a duct,   (C) reacting the gaseous combustion products and the fuel in the duct in an endothermic reaction under conditions effective to form syngas comprising hydrogen and carbon monoxide and to form soot which is entrained in the syngas, and   (D) passing said syngas and entrained soot from said duct into said furnace and combusting the syngas and entrained soot in the furnace with one or more oxidant streams injected into said furnace.   
     
     
         3 . The method of  claim 1  wherein the furnace contains material that contains fine particulate matter or material that upon being heated in the furnace produces fine particulate matter by decrepitation, and the combustion of the syngas and entrained soot in the furnace accelerates the formation of a glassy layer on said material which thereby reduces the fine particulate matter from being entrained into gaseous combustion products in the furnace. 
     
     
         4 . The method of  claim 1  further comprising adding to (a) the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the heated second regenerator, or to (b) the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the heated first regenerator, or to both (a) and (b), additional material which forms soot in said heated regenerator. 
     
     
         5 . The method of  claim 1  further comprising adding soot to (a) the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the heated second regenerator, or to (b) the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the heated first regenerator, or to both (a) and (b). 
     
     
         6 . The method of  claim 1  wherein said hydrocarbon fuel is natural gas and the molar ratio of the portion of said cooled portion of gaseous combustion products from said first regenerator passed into a heated second regenerator and said hydrocarbon fuel is less than 0.5:1. 
     
     
         7 . The method of  claim 1  wherein said cooled portion of gaseous combustion products from said first regenerator passed into a heated second regenerator contains more than 0.1 g per Nm 3  of particulates and enhances radiative heat transfer in said second regenerator. 
     
     
         8 . The method of  claim 1  wherein the gaseous combustion products passed from the furnace into the cooled first regenerator and the gaseous combustion products passed from the furnace into the cooled second regenerator contain no soot. 
     
     
         9 . The method of  claim 2  wherein the furnace contains material that contains fine particulate matter or material that upon being heated in the furnace produces fine particulate matter by decrepitation, and the combustion of the syngas and entrained soot in the furnace accelerates the formation of a glassy layer on said material which thereby reduces the fine particulate matter from being entrained into gaseous combustion products in the furnace. 
     
     
         10 . The method of  claim 2  further comprising adding to the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the duct, additional material which will form soot in said duct. 
     
     
         11 . The method of  claim 2  further comprising adding soot to the cooled portion of gaseous combustion products, and hydrocarbon fuel, which is passed into the duct. 
     
     
         12 . The method of  claim 2  wherein the gaseous combustion products passed from the furnace into the duct contain no soot.