Industrial radiant heater

Abstract

High temperature industrial radiant heaters may be improved by coating a refractory or lining in and adjacent to the flame impingement zone which refractory or lining does not transmit fuel to the burner with a metal oxide catalyst or metal oxide catalyst precursor other than iron, iron oxides or mixtures thereof, to promote the burning of one or more of the fuel, and combustion products thereof.

1 . In a fluid fueled heater, comprising a mechanical burner, a flame impingement zone adjacent said burner, and a refractory or lining in and adjacent to the flame impingement zone which refractory or lining does not transmit fuel to the burner the improvement of substantially coating the refractory or lining with a metal oxide catalyst or metal oxide catalyst precursor other than iron, iron oxides, and mixtures thereof, to promote the burning of one or more of the fuel, and combustion products from the fuel.  
   
   
       2 . The heater according to claim 1 , wherein the fuel is fluid hydrocarbon.  
   
   
       3 . The heater according to  claim 2 , wherein the refractory is selected from the group consisting of dolomites, silicon carbide, aluminates, aluminum silicates, chromites, silica, alumina, zirconia, magnesia, Al 2 O 3 , and ZrO 2  and mixtures thereof.  
   
   
       4 . The heater according to  claim 3 , wherein during operation the refractory is at a temperature from 600° C. to 1300° C.  
   
   
       5 . The heater according to  claim 4 , wherein the refractory has a porosity of not less than 0.1 cc/g.  
   
   
       6 . The heater according to  claim 5 , wherein the refractory or lining is in the form of bricks, a metal lining on refractory bricks or refractory metals.  
   
   
       7 . The heater according to  claim 6 , wherein the fuel is a gaseous hydrocarbon.  
   
   
       8 . The heater according to  claim 7 , wherein the metal oxide is selected from the group consisting of oxides of perovskites, hexaaluminate, spinels, PtO, PdO, MgO, Ce 2 O 3 , CoO, Cr 2 O 3 , CuO, MnO, NiO, and their precursors and mixtures thereof.  
   
   
       9 . The heater according to  claim 8 , wherein the thickness of the metal oxide coating on the refractory from 0.0001 to 5 mm thick.  
   
   
       10 . The heater according to  claim 9 , wherein the refractory is selected from the group consisting of silica, Al 2 O 3 , aluminium silicates, ZrO 2 , magnesia and mixtures thereof  
   
   
       11 . The heater according to  claim 10 , wherein the metal oxide is selected from the group consisting of oxides of PtO, PdO, MgO, Ce 2 O 3 , CoO, CuO, Cr 2 O 3 , MnO, NiO, and a mixture thereof  
   
   
       12 . The heater according to  claim 11 , where in a refractory is exposed to the flame in the flame impingement zone.  
   
   
       13 . The heater according to  claim 11 , wherein a metal liner is exposed to the flame in the flame impingement zone.  
   
   
       14 . The heater according to  claim 12  which is in the radiant heater of a steam cracker.  
   
   
       15 . The heater according to  claim 14 , wherein the fuel is natural gas or a natural gas rich fuel.  
   
   
       16 . The heater according to  claim 13  which is in the radiant heater of a steam cracker.  
   
   
       17 . The heater according to  claim 16 , wherein the fuel is natural gas.  
   
   
       18 . A process for preparing a refractory or lining having a metal oxide or metal oxide precursor component which catalyses the burning of a fluid fuel or combustion products from a fluid fuel when subject to flame impingement selected from the group consisting of: 
 a) direct application of a coating composition comprising said metal oxide or metal oxide precursor to the refractory or lining surface; and    b) incorporating said metal oxide or metal oxide precursor into the refractory or lining composition during manufacture of said refractory.    
   
   
       19 . The process according to  claim 18 , wherein said metal oxide or metal oxide precursor is applied to the surface of said refractory or lining in the form of a paint or paste.  
   
   
       20 . The process according to clam  19 , wherein said paint is applied to the surface of said refractory or lining by an applicator selected from the group consisting of brush, roller and spray device.  
   
   
       21 . The process according to  claim 20  which is carried out prior to installation of said refractory or lining in said burner.  
   
   
       22 . The process according to  claim 20 , which is carried out during scheduled maintenance of said burner.  
   
   
       23 . A method to increase burner stability by substantially coating the refractory or lining in the flame impingement zone with a metal oxide catalyst or precursor for a metal oxide catalyst to promote the burning of one or more of the fuel and the combustion products.