Municipal solid waste fuel steam generator with waterwall furnace platens

Abstract

A steam generator includes a furnace configured and adapted to generate a stream of furnace exit gases from the combustion of municipal solid waste fuel. At least one superheater is disposed within an upper portion of the furnace or backpass. The superheater is configured and adapted to superheat fluids within the superheater by facilitating heat transfer between fluids within the superheater and furnace exit gases outside the superheater. At least one waterwall furnace platen is disposed within the furnace upstream from the superheater, the waterwall furnace platen is configured and adapted to lower furnace exit gas temperature at the superheater by facilitating heat transfer between fluids within the waterwall furnace platen and furnace exit gases outside the waterwall furnace platen.

1 . A steam generator comprising:
 a) a furnace configured and adapted to generate a stream of furnace exit gases from combustion of municipal solid waste fuel;   b) at least one superheater disposed downstream of a combustion zone of the furnace, the superheater being configured and adapted to superheat fluids within the superheater by facilitating heat transfer between fluids within the superheater and furnace exit gases outside the superheater; and   c) at least one waterwall furnace platen disposed within the furnace upstream from the superheater, the waterwall furnace platen being configured and adapted to lower furnace exit gas temperature at the superheater by facilitating heat transfer between fluids within the waterwall furnace platen and furnace exit gases outside the waterwall furnace platen.   
     
     
         2 . A steam generator as recited in  claim 1 , wherein at least one superheater and waterwall furnace platen are in fluid communication with each other as part of a thermal hydraulic circuit. 
     
     
         3 . A steam generator as recited in  claim 1 , further comprising a corrosion resistant overlay disposed on an outer surface of the waterwall furnace platen. 
     
     
         4 . A steam generator as recited in  claim 3 , wherein the overlay includes an Inconel® alloy. 
     
     
         5 . A steam generator as recited in  claim 4 , wherein the overlay includes Inconel® 625. 
     
     
         6 . A steam generator as recited in  claim 1 , wherein the at least one waterwall furnace platen is positioned within the furnace to allow maintenance access to the superheater. 
     
     
         7 . A steam generator as recited in  claim 1 , further comprising mechanical means operably connected to the at least one waterwall furnace platen to vibrate the platen during operation and reduce residue build-up on exterior surfaces of the platen. 
     
     
         8 . A steam generator as recited in  claim 1 , wherein the at least one waterwall furnace platen header piping includes an expansion loop configured and adapted to accommodate for thermal expansion by flexing. 
     
     
         9 - 13 . (canceled) 
     
     
         14 . A steam generation plant comprising:
 a) a furnace configured and adapted to generate a stream of furnace exit gases from combustion of municipal solid waste fuel;   b) at least one superheater disposed downstream of a combustion zone of the furnace, the superheater being configured and adapted to facilitate heat transfer between fluids within the superheater and furnace exit gases outside the superheater;   c) at least one waterwall furnace platen disposed within the furnace upstream from the superheater, the waterwall furnace platen being configured and adapted to lower furnace exit gas temperature at the superheater by facilitating heat transfer between fluids within the waterwall furnace platen and furnace exit gases outside the superheater; and   d) a steam powered system in fluid communication with the superheater.   
     
     
         15 . A steam generation plant as recited in  claim 14 , wherein the steam powered system includes a high-pressure turbine. 
     
     
         16 . A steam generation plant as recited in  claim 14 , wherein the steam powered system includes a steam host. 
     
     
         17 . A steam generation plant as recited in  claim 14 , wherein the steam powered system includes a district heating system. 
     
     
         18 . A steam generation plant as recited in  claim 14 , wherein at least one superheater and waterwall furnace platen are in fluid communication with each other as part of a thermal hydraulic circuit. 
     
     
         19 . A steam generation plant as recited in  claim 14 , further comprising a corrosion resistant overlay disposed on an outer surface of the at least one waterwall furnace platen. 
     
     
         20 . A steam generation plant as recited in  claim 19 , wherein the overlay comprises an Inconel® alloy. 
     
     
         21 . A steam generation plant as recited in  claim 20 , wherein the overlay comprises Inconel® 625. 
     
     
         22 . A steam generation plant as recited in  claim 14 , wherein the at least one waterwall furnace platen is positioned within the furnace to allow maintenance access to the superheater. 
     
     
         23 . A steam generation plant as recited in  claim 14 , wherein the at least one waterwall furnace platen includes a header piping expansion loop configured and adapted to accommodate for thermal expansion by flexing. 
     
     
         24 . A steam generation plant as recited in  claim 14 , further comprising mechanical means operably connected to the at least one waterwall furnace platen to vibrate the platen during operation and reduce residue build-up on exterior surfaces of the platen. 
     
     
         25 - 28 . (canceled) 
     
     
         29 . A method of enhancing NO x  control in a municipal solid waste fuel steam generator, comprising steps of:
 a) providing a furnace configured and adapted to generate a stream of furnace exit gas from combustion of municipal solid waste fuel, the furnace having at least one superheater disposed downstream of a combustion zone of the furnace, and at least one waterwall furnace platen disposed within the furnace upstream from the superheater;   b) operating the furnace to generate steam from the super heater; and   c) enhancing NO x  reduction by circulating fluids through the at least one waterwall furnace platen to lower furnace exit gas temperature at the superheater.   
     
     
         30 - 32 . (canceled)