High performance fired heater tubes

Abstract

Fired heater tubes with improved resistance to corrosion and fouling suitable for use in thermal processing units of petroleum refineries and petrochemical plants are fabricated from a bulk alloy of an alumina-forming alloy which is capable of forming a stable oxide film on the surfaces of the tubes. The bulk alloy comprising about 3 wt. % to about 20 wt. % of Al, about 5 wt. % to about 30 wt. % Cr and at least one alloying component selected from Fe, Ni, Co, Si, Mn, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and mixtures of these components.

We claim: 
     
         1 . A fired heater tube having an inner surface and an outer surface formed from an alumina-forming bulk alloy comprising about 3 wt. % to about 20 wt. % of Al, about 5 wt. % to about 30 wt. % Cr and at least one element selected from the group consisting of Fe, Ni, Co, Si, Mn, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and mixtures thereof, the tube having a surface oxide layer on at least one of its alumina-forming bulk alloy surfaces, substantially comprised of alumina, chromia, silica, mullite, spinels, or mixtures thereof. 
     
     
         2 . The fired heater tube of  claim 1  in which the surface oxide layer is formed on the inner surface of the tube. 
     
     
         3 . The fired heater tube of  claim 1  in which the oxide layer is alumina. 
     
     
         4 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 3 wt. % to about 10 wt. % of aluminum. 
     
     
         5 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 3 wt. % to about 3.5 wt. % of aluminum. 
     
     
         6 . The fired heater tube of  claim 5  in which the alumina forming bulk alloy comprises about 1 wt. % to about 3 wt. % of niobium. 
     
     
         7 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 10 wt. % to about 20 wt. % of chromium. 
     
     
         8 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 12 wt. % to about 18 wt. % of chromium. 
     
     
         9 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 18 wt. % to about 30 wt. % of nickel. 
     
     
         10 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises about 20 wt. % to about 25 wt. % of nickel. 
     
     
         11 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises less than about 0.8 wt. % of silicon. 
     
     
         12 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises less than about 0.15 wt. % carbon, 
     
     
         13 . The fired heater tube of  claim 1  in which the alumina forming bulk alloy comprises less than about 0.1 wt. % carbon 
     
     
         14 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 0.01 wt. % to about 4.0 wt. % of at least one element selected from Mn, Ti, Zr, Hf, V, Nb, Ta, Mo and W. 
     
     
         15 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 0.01 wt. % to about 2.0 wt. % of at least one element selected from Al, Si, Sc, La, Y and Ce. 
     
     
         16 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 0.01 wt. % to about 2.0 wt. % of at least one element selected from Ga, Ge, As, In, Sn, Sb, Pb, Pd, Pt, Cu, Ag and Au. 
     
     
         17 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 0.01 wt. % to about 2.0 wt. % of at least one element selected from Re, Ru, Rh, Ir, Pd, Pt, Cu, Ag and Au. 
     
     
         18 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 0.01 wt. % to about 2.0 wt. % of oxide particles of at least one element selected from Al, Si, Sc, La, Y and Ce. 
     
     
         19 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises, in addition to iron as the balance, about 18 wt. % to about 30 wt. % Ni, about 12 wt. % to about 18 wt. % chromium, about 3.0 wt. % to about 5.5 wt. % aluminum, about 1.0 wt. % to about 3.0 wt. % of niobium, and about 0.01 wt. % to about 3.0 wt. % of at least one element selected from Mo, Mn, Si, Cu, W, V, Ti, Hf, Y, C, B, and P. 
     
     
         20 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises, in addition to iron as the balance, about 20 wt. % to about 25 wt. % Ni, about 14 wt. % to about 16 wt. % Cr, about 3.0 wt. % to about 4.0 wt. % Al, about 1.0 wt. % to about 3.0 wt. % of niobium, and about 0.01 wt. % to about 3.0 wt. % of at least one element selected from Mo, Mn, Si, Cu, W, V, Ti, Hf, Y, C, B, and P. 
     
     
         21 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 25.0 wt. % Ni, 15.0 wt. % Cr, 4.0 wt. % Al, 2.5 wt. % Nb, 2.0 wt. % Mo, 2.0 wt. % Mn, 0.15 wt. % Si, 0.1 wt. % C, 0.01 wt. % B, 0.15 wt. % Hf, 0.07 wt. % Y, balance Fe. 
     
     
         22 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 25.0 wt. % Ni, 14.0 wt. % Cr, 3.55 wt. % Al, 2.53 wt. % Nb, 2.0 wt. % Mo, 2.0 wt. % Mn, 0.14 wt. % Si, 0.1 wt. % C, 0.51 wt. % Cu, 0.95 wt. % W, 0.04 wt. % V, 0.05 wt. % Ti, balance Fe. 
     
     
         21 . The fired heater tube of  claim 1  in which the oxide layer of the alumina forming bulk alloy has a porosity of less than about 3 volume percent. 
     
     
         22 . The fired heater tube of  claim 1  in which the oxide layer of the alumina forming bulk alloy has a porosity of less than about 1 volume percent. 
     
     
         23 . The fired heater tube of  claim 1  in which the oxide layer has a thickness from about 1 nm to about 100 μm. 
     
     
         24 . The fired heater tube of  claim 1  in which the oxide layer has a thickness from 100 nm to about 10 μm. 
     
     
         25 . The fired heater tube according to  claim 1  in which the coating metal layer has an average surface roughness (Ra) of less than 40 micro inches (1.1 μm). 
     
     
         26 . The fired heater tube according to  claim 1  in which the coating metal layer has an average surface roughness (Ra) of less than 20 micro inches (0.5 μm) 
     
     
         27 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 15.0 wt. % Cr, about 3.0 wt. % Al, about 25.0 wt. % Ni, about 2.5 wt. % Nb, about 2.0 wt. % Mo, about 2.0 wt. % Mn, about 0.15 wt. % Si, about 0.1 wt. % C, about 0.01 wt. % B, about 0.15 wt. % Hf, about 0.07 wt. % Y, balance Fe. 
     
     
         28 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 15.0 wt. % Cr, about 4.0 wt. % Al, about 25.0 wt. % Ni, about 2.5 wt. % Nb, about 2.0 wt. % Mo, about 2.0 wt. % Mn, about 0.15 wt. % Si, about 0.1 wt. % C, about 0.01 wt. % B, about 0.15 wt. % Hf, about 0.07 wt. % Y, balance Fe. 
     
     
         29 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 14.2 wt. % Cr, about 3.0 wt. % Al, about 20.0 wt. % Ni, about 2.5 wt. % Nb, about 2.0 wt. % Mo, about 2.0 wt. % Mn, about 0.14 wt. % Si, about 0.1 wt. % C, about 0.02 wt. % P, about 0.51 wt. % Cu, about 0.97 wt. % W, about 0.04 wt. % V, about 0.05 wt. % Ti, balance Fe. 
     
     
         30 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 14.3 wt. % Cr, about wt. % 3.0Al, about 25.0 wt. % Ni, about 1.0 wt. % Nb, about 2.0 wt. % Mo, about 2.0 wt. % Mn, about 0.14 wt. % Si, about 0.05 wt. % C, about 0.51 wt. % Cu, about 0.96 wt. % W, about 0.04 wt. % V, about 0.05 wt. % Ti , balance Fe. 
     
     
         31 . The fired heater tube according to  claim 1  in which the alumina forming bulk alloy comprises about 14.0 wt. % Cr, about 3.55 wt. % Al, about 25.0 wt. % Ni, about 2.53 wt. % Nb, about 2.0 wt. % Mo, about 2.0 wt. % Mn, about 0.14 wt. % Si, about 0.1wt. % C, about 0.51 wt. % Cu, about 0.95 wt. % W, about 0.04 wt. % V, about 0.05 wt. % Ti , balance Fe.32. A petroleum refinery thermal processing unit having a fired heater with heater tubes according to  claim 1 . 
     
     
         33 . A petroleum refinery thermal processing unit having a fired heater with heater tubes according to  claim 1  in the radiant section. 
     
     
         34 . A petrochemical thermal processing unit having a fired heater with heater tubes according to  claim 1 . 
     
     
         35 . A petrochemical thermal processing unit having a fired heater with heater tubes according to  claim 1  in the radiant section.