System and method for retrofitting a burner front and injecting a second fuel into a utility furnace

Abstract

This disclosure may relate generally to systems, devices, and methods for a injecting a compound through a sootblower, burner or other utility furnace hardware, such that the compound can be delivered to targeted areas on the inside of a utility furnace. In one embodiment, the compound is a chemical for improving environmental controls. In another embodiment, the compound is a fuel. In that embodiment, compound can facilitate retrofitting a burner to a dual fired utility furnace. In another embodiment, the compound is a chemical for removing slag from the furnace.

I claim: 
     
         1 . A method of retrofitting a utility furnace, wherein the utility furnace has a burner front, wherein the burner front fires the utility furnace with a first fuel type, and wherein the burner front supplies combustion air associated with the combustion of the first fuel type, wherein the combustion air is delivered into the utility furnace via a delivery mechanism, wherein the combustion air comprises at least one of: primary air, secondary air, and tertiary air, the method comprising:
 connecting a source of a second fuel type to the delivery mechanism for the combustion air, wherein the connection is configured to introduce the second fuel type into the combustion air at a location outside of the burner front;   wherein the first fuel type is a different type of fuel from the second fuel type.   
     
     
         2 . The method of  claim 1 , wherein the utility furnace is a coal fired furnace and the first fuel type is coal. 
     
     
         3 . The method of  claim 2 , wherein the second fuel type is one of: a liquid and a gas. 
     
     
         4 . The method of  claim 3 , wherein the second fuel type is natural gas liquid (NGL). 
     
     
         5 . The method of  claim 3 , wherein the second fuel type is liquefied natural gas (LNG). 
     
     
         6 . The method of  claim 2 , wherein the first fuel type is coal and the second fuel type is natural gas, and further comprising pneumatically conveying the coal and the natural gas in the combustion air, which comprises primary air. 
     
     
         7 . The method of  claim 2 , wherein the first fuel type is coal and the second fuel type is natural gas, and further comprising providing the coal and the natural gas into the utility furnace in the combustion air via the same burner. 
     
     
         8 . A method of injecting a compound into a utility furnace comprising:
 injecting a compound into a preexisting fluid stream;   wherein the preexisting fluid stream is a fluid stream carried in an already existing conveyance device, wherein the already existing conveyance device was connected to the utility furnace, in such a manner as to inject the preexisting fluid stream into the utility furnace, prior to retrofitting the utility furnace to provide the ability to inject the compound into the fluid stream;   wherein the preexisting fluid stream comprises combustion air carrying a first fuel of a first fuel type;   injecting the preexisting fluid stream, containing the compound, into the utility furnace through a burner front, wherein the compound comprises a second fuel of a second fuel type, the compound comprising one of: a solid, a liquid, and a gas;   wherein the first fuel type is different from the second fuel type, and wherein the compound is injected at a location outside of the burner front.   
     
     
         9 . The method of  claim 8 , wherein the preexisting fluid stream is one of primary, secondary, and tertiary air. 
     
     
         10 . The method of  claim 8 , wherein the compound is one of: the liquid and the gas. 
     
     
         11 . The method of  claim 8 , wherein the compound is a fuel other than a primary fuel for firing the utility furnace. 
     
     
         12 . The method of  claim 8 , wherein the first fuel type is coal and wherein the second fuel type is liquefied natural gas. 
     
     
         13 . The method of  claim 11 , wherein the primary fuel is coal and wherein the compound comprises natural gas liquid (NGL). 
     
     
         14 . A utility furnace comprising:
 a burner within a burner front;   a delivery mechanism, wherein the delivery mechanism is configured to deliver combustion air into the utility furnace, wherein the delivery mechanism is configured to deliver combustion air into the utility furnace in the vicinity of the burner, wherein the combustion air comprises one of primary air, secondary air and tertiary air;   a first fuel source of a first fuel provided to the burner, wherein the first fuel source is a first fuel type and is delivered to the utility furnace via the combustion air; and   a second fuel source of a second fuel comprising a second fuel type that is different from the first fuel type, wherein the second fuel source is connected to the delivery mechanism at a location that is outside of the burner front, wherein the second fuel source is configured to inject the second fuel of the second fuel type into the combustion air in the delivery mechanism.   
     
     
         15 . The utility furnace of  claim 14 , wherein the first fuel and the second fuel both enter the burner front via a pulverized coal pipe conveyed pneumatically via the primary air. 
     
     
         16 . The utility furnace of  claim 15 , wherein the second fuel type is one of: a liquid and a gas. 
     
     
         17 . The utility furnace of  claim 15 , wherein the second fuel type is natural gas liquid (NGL). 
     
     
         18 . The utility furnace of  claim 15 , wherein the second fuel type is liquefied natural gas (LNG). 
     
     
         19 . The utility furnace of  claim 15 , wherein the first fuel is supplied to the utility furnace in a coal burner tube and wherein the second fuel is connected to the coal burner tube at a location that is outside of the burner front and wherein the second fuel is supplied to the utility furnace along with the first fuel in the coal burner tube.