Component in a combustion system, and process for preventing slag, ash, and char buildup

Abstract

Disclosed herein is a component in a combustion system comprising a composite, the composite comprising silicon carbide; and a refractory metal silicide comprising a phase selected from Rm 5 Si 3 , Rm 5 Si 3 C, RmSi 2 , and a combination thereof; wherein Rm is a refractory metal selected from molybdenum, tungsten, and a combination thereof. Also disclosed is a process for preventing slag, ash, and char buildup on a surface, comprising disposing a first surface of the composite on the surface; replacing a component comprising the surface with a component consisting of the composite; or a combination thereof.

1 . A component in a combustion system comprising a composite, the composite comprising:
 silicon carbide; and   a refractory metal silicide comprising a phase selected from Rm 5 Si 3 , Rm 5 Si 3 C, RmSi 2 , and a combination thereof;   wherein Rm is a refractory metal selected from molybdenum, tungsten, and a combination thereof.   
     
     
         2 . The component in the combustion system of  claim 1 , wherein the composite comprises about 75 to about 98 percent by volume of the silicon carbide, wherein percent by volume is based on a total volume of the silicon carbide and the refractory metal silicide. 
     
     
         3 . The component in the combustion system of  claim 1 , wherein the composite comprises about 2 to about 25 percent by volume of the refractory metal silicide, wherein percent by volume is based on a total volume of the silicon carbide and the refractory metal silicide. 
     
     
         4 . The component in the combustion system of  claim 1 , wherein the refractory metal silicide comprises:
 about 0 to about 97 percent by weight molybdenum; and   about 3 to about 100 percent by weight tungsten;   wherein percent by weight is based on a total weight of molybdenum and tungsten.   
     
     
         5 . The component in the combustion system of  claim 1 , wherein the composite further comprises pores. 
     
     
         6 . The component in the combustion system of  claim 6 , wherein the composite comprises about 10 to about 45 percent by volume of the pores, and about 55 to about 90 percent by volume of the silicon carbide and the refractory metal silicide, wherein percent by volume is based on a total volume of the composite. 
     
     
         7 . The component in the combustion system of  claim 1 , wherein the composite further comprises rhenium, tantalum, niobium, titanium, zirconium, hafnium, vanadium, chromium, iron, nickel, cobalt, or a combination thereof. 
     
     
         8 . The component in the combustion system of  claim 1 , wherein the composite further comprises about 0.01 to about 2 percent by weight iron, based on a total weight of molybdenum and tungsten. 
     
     
         9 . The component in the combustion system of  claim 1 , wherein the composite comprises a specific resistivity of about 0.000001 to about 0.5 ohm·cm. 
     
     
         10 . The component in the combustion system of  claim 1 , wherein the silicon carbide and the refractory metal silicide comprise 100 percent of the amount of carbon and 100 percent of the amount of silicon in the composite. 
     
     
         11 . The component in the combustion system of  claim 1 , wherein the component consists of the composite. 
     
     
         12 . The component in the combustion system of  claim 1 , wherein the component defines a gasifier, a gasification feed injector, an injector nozzle, a gasifier thermocouple, a gasifier thermocouple well, a gasifier thermocouple sheath, an injector barrel, an injector barrel cooling coil, a gasification feed injector shield, a gasifier lining, a gasification radiant syngas heat exchanger component, a gasification convective syngas heat exchanger component, a posimetric pump transition piece, a posimetric pump dry coal feed transition piece, a posimetric dry coal feed pump abutment, a posimetric pump dry coal feed rotor disk, a turbine bucket, a turbine blade, a turbine nozzle, a turbine rotor, a turbine disk, a turbine vane, a turbine stator, a turbine shroud, a turbine combustor, or a combination thereof. 
     
     
         13 . A component in a combustion system comprising a composite, the composite comprising:
 about 50 to about 85 percent by volume silicon carbide;   about 4.9 to about 25 percent by volume of a phase of a refractory metal silicide selected from Rm 5 Si 3 , Rm 5 Si 3 C, and a combination thereof;   about 0.1 to about 20 percent by volume of a phase of a refractory metal silicide selected from RmSi 2 ; and   about 10 to about 45 percent by volume pores;   wherein percent by volume is based on a total volume of the composite;   wherein Rm is a refractory metal selected from molybdenum, tungsten, and a combination thereof;   wherein the composite comprises the molybdenum in an amount of about 45 to about 80 percent by weight and the tungsten in an amount of about 20 to about 55 percent by weight;   wherein the composite further comprises iron in an amount of about 0 to about 2 percent by weight; and   wherein percent by weight is based on a total weight of molybdenum and tungsten.   
     
     
         14 . The component in the combustion system of  claim 13 , wherein the composite comprises a specific resistivity of about 0.000001 to about 0.5 ohm·cm.