Furnace tunnels and assembly system

Abstract

Flue gas entry into the tunnel(s) of a furnace is controlled by openings through the entry ports. A furnace tunnel assembly system uses interlocking refractory blocks to form a longitudinal wall of a flue gas flow channel in a firebox. Plugs in some of the ports inhibit flue gas entry from the firebox to the flow channel, and flow passages in some of the ports allow the flue gas to enter the flow channel from the firebox. The flow passages can be provided as inserts having orifices of varying diameter and a profile matching the ports in which they are placed. Matching the flow conductivity (or cross-sectional flow area) and pressure drop through the individual ports to the desired mass flow, the flue gas flow can be distributed evenly, or as otherwise desired, into different ports, intervals, and/or regions of the tunnel.

What is claimed is: 
     
         1 . A furnace tunnel assembly system comprising:
 a plurality of interlocking refractory blocks adapted to form a longitudinal wall of a flue gas flow channel in a firebox;   at least some of the blocks comprising ports integrally formed therein, wherein the ports are arranged in regular rows and columns; and   inserts for the ports, wherein at least some of the inserts comprise plugs comprising imperforate plates having a profile matching the ports to inhibit flue gas entry from the firebox to the flow channel, and wherein some of the ports comprise flow passages for the flue gas to enter the flow channel from the firebox.   
     
     
         2 . The furnace tunnel assembly system of  claim 1 , further comprising tie rods. 
     
     
         3 . The furnace tunnel assembly system of  claim 2 , wherein some of the plugs provide attachment points for the tie rods. 
     
     
         4 . The furnace tunnel assembly system of  claim 1 , further comprising:
 wherein at least some of the flow passages have a relatively different flow conductivity than at least some of the other flow passages; and   wherein the different flow conductivities are provided to control flue gas entry into the flow channel.   
     
     
         5 . The furnace tunnel assembly system of  claim 4 , wherein some of the inserts comprise perforated plates having a profile matching the ports. 
     
     
         6 . The furnace tunnel assembly system of  claim 5 , wherein the perforations in some of the perforated plates have a cross-sectional flow area that is greater with respect to the perforations of some of the other perforated plates. 
     
     
         7 . The furnace tunnel assembly system of  claim 6 , wherein the perforated plates comprise sets of a plurality of the perforated plates, wherein the perforations within each set of perforated plates have a uniform cross-sectional flow area that differs with respect to the other one or more sets of perforated plates. 
     
     
         8 . The furnace tunnel assembly system of  claim 7 , wherein the ports are disposed in a plurality of intervals comprising a near interval adjacent to an open end of the flow channel, a far interval spaced away from the open end, and a plurality of intermediate intervals between the near and far intervals, wherein the passages through the ports provide the far interval with an overall flue gas flow conductivity relatively greater than the overall flue gas flow conductivity of the near interval, and wherein the overall flue gas flow conductivities of the respective intermediate intervals increase successively from the near interval to the far interval. 
     
     
         9 . The furnace tunnel assembly system of  claim 8 , wherein a mass flow rate of the flue gas through each interval is no more than 2% greater or less than an overall average of the mass flow rate through the intervals. 
     
     
         10 . The furnace tunnel assembly system of  claim 1 , wherein the ports are disposed in a plurality of intervals comprising a near interval adjacent to an open end of the flow channel, a far interval spaced away from the open end, and a plurality of intermediate intervals between the near and far intervals, wherein the flow passages through the ports provide the far interval with an overall cross sectional flow area greater than the overall cross sectional flow area of the near interval, and wherein the overall cross sectional flow areas of the respective intermediate intervals increase successively from the near interval to the far interval, and wherein a mass flow rate of the flue gas through each interval is no more than 2% greater or less than an overall average of the mass flow rate through the intervals. 
     
     
         11 . The furnace tunnel assembly system of  claim 1 , further comprising:
 wherein the ports are disposed in a plurality of intervals comprising a near interval adjacent to the open end, a far interval spaced away from the open end, and a plurality of intermediate intervals between the near and far intervals;   wherein each of the near, far and intermediate intervals have the same number of ports;   wherein the ports have a uniform profile and receive respective plugs or perforated plates having a matching profile;   wherein the perforated plates comprise one or more sets of the perforated plates having a uniform perforation diameter;   wherein the far interval has an overall cross sectional flow area greater than the overall cross sectional flow area of the near interval, and the overall cross sectional flow areas of the respective intermediate intervals increase successively from the near interval to the far interval.   
     
     
         12 . The furnace tunnel assembly system of  claim 11  wherein the perforated plates in each interval comprise perforated plates from a plurality of different sets. 
     
     
         13 . The furnace tunnel assembly system of  claim 11 , further comprising a plurality of sets of the perforated plates, wherein the perforated plates within each set have respective perforations of the same size, and wherein each set has different perforation sizes than the other sets. 
     
     
         14 . The furnace tunnel assembly system of  claim 11 , wherein the ports are arranged in regular rows and columns. 
     
     
         15 . The furnace tunnel assembly system of  claim 14 , wherein the ports are arranged in a triangular pattern or a square pattern. 
     
     
         16 . A furnace tunnel assembly system comprising:
 a plurality of interlocking refractory blocks adapted to form a longitudinal wall of a flue gas flow channel in a firebox;   at least some of the blocks comprising ports formed therein, wherein the ports are arranged in regular rows and columns; and   respective inserts for the ports, wherein at least some of the inserts comprise plugs comprising imperforate plates, and wherein some of the inserts comprise perforated plates.   
     
     
         17 . The furnace tunnel assembly system of  claim 16  wherein the ports are disposed in a plurality of intervals comprising a near interval adjacent to an open end of the flow channel, a far interval spaced away from the open end, and a plurality of intermediate intervals between the near and far intervals, wherein the perforations provide the far interval with an overall cross sectional flow area greater than the overall cross sectional flow area of the near interval, and wherein the overall cross sectional flow areas of the respective intermediate intervals increase successively from the near interval to the far interval. 
     
     
         18 . The furnace tunnel assembly system of  claim 17 , wherein a mass flow rate of the flue gas through each interval is no more than 2% greater or less than an overall average of the mass flow rate through the intervals. 
     
     
         19 . A furnace comprising a firebox and a furnace tunnel assembled from the furnace tunnel assembly system of  claim 1 . 
     
     
         20 . A furnace comprising a firebox and a furnace tunnel assembled from the furnace tunnel assembly system of  claim 16 . 
     
     
         21 . A method comprising assembling a furnace tunnel from the blocks and inserts of  claim 1 . 
     
     
         22 . A method comprising assembling a furnace tunnel from the blocks, inserts, and tie rods of  claim 16 . 
     
     
         23 . A method comprising:
 positioning a plurality of interlocking refractory blocks to form a longitudinal wall of a flue gas flow channel in a firebox, wherein at least some of the blocks comprising ports integrally formed therein;   arranging the ports in regular rows and columns;   plugging some of the ports with plugs comprising imperforate plates having a profile matching the ports to inhibit flue gas entry from the firebox to the flow channel; and   providing some of the ports with flow passages for the flue gas to enter the flow channel from the firebox.