Furnace tube radiants

Patent metadata

Field	Value
Publication number	US-10808181-B2
Application number	US-201615352720-A
Country	US
Kind code	B2
Filing date	Nov 16, 2016
Priority date	Nov 17, 2015
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

A substantially linear ceramic or metallic radiant of ellipsoidal or polygonal cross section is placed proximate furnace tubes or coils in the radiant section of a fired heater to increase the radiant heat directed to the surface of the tubes or coils.

First claim

What is claimed is:

1. In the radiant section of a fired heater chemical cracker at least two radiants separate from at least one wall, and intermediate to vertical tubes which carry hydrocarbons through the radiant section of the chemical cracker, said radiant having a melting point greater than 1250° C., and creep and deformation properties not less than 85% of creep and deformation properties of the tubes in the radiant section of the fired heater chemical cracker, comprising a ceramic or alloy having a closed continuous surface.

2. The radiant according to claim 1 , in the form of a substantially linear element with cross section of ellipsoid or polygon.

3. The radiant according to claim 2 , having an external surface which is smooth or modified with grooves or micro-protuberances.

4. The radiant according to claim 2 , comprising a continuous element.

5. The radiant according to claim 4 , having a length from 25 to 100% of the length of a tube pass in the radiant section of a fired heater chemical cracker.

6. The radiant according to claim 5 , having a length from 50 to 90% of the length of a tube pass in the radiant section of a fired heater chemical cracker a width from ¼ to ¾ of the external diameter of the furnace tube.

7. The radiant according to claim 6 , which is vertical.

8. The radiant according to claim 4 which is an alloy and has a surface having a thickness from 10 to 5,000 microns comprising from 40 to 60 weight % of compounds of the formula Mn x Cr 3-x O 4 wherein x is from 0.5 to 2 and from 60 to 40 weight % of oxides of Mn and Si selected from MnO, MnSiO 3 , Mn 2 SiO 4 and mixtures thereof provided that the surface contains less than 5 weight % of Cr 2 O 3 .

9. The radiant according to claim 4 , comprising from about 55 to 65 weight % of Ni; from about 20 to 10 weight % of Cr; from about 20 to 10 weight % of Co; and from about 5 to 9 weight % of Fe and the balance one or more of the trace elements.

10. The radiant according to claim 9 , further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % the sum of the components adding up to 100 weight %.

11. The radiant according to claim 4 , comprising from 40 to 65 weight % of Co; from 15 to 20 weight % of Cr; from 20 to 13 weight % of Ni; less than 4 weight % of Fe and the balance of one or more trace elements and up to 20 weight % of W the sum of the components adding up to 100 weight %.

12. The radiant according to claim 11 , further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight %.

13. The radiant according to claim 4 , comprising from 20 to 38 weight % of chromium from 25 to 48, weight % of Ni.

14. The radiant according to claim 13 , further comprising from 0.2 up to 3 weight % of Mn, from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % and the balance substantially iron.

15. The radiant according to claim 4 , comprising a ceramic selected from silicon dioxide, fused silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, thorium dioxide, lanthanum oxide, magnesium oxide, calcium oxide, barium oxide, tin oxide, cerium dioxide, zinc oxide, boron oxide, boron carbide, yttrium oxide, aluminum silicate, silicon nitride, silicon carbide and mixtures thereof.

16. The radiant according to claim 2 , comprising multiple joined segments.

17. The radiant according to claim 16 , having a length from 25 to 100% of the length of a tube pass in the radiant section of a fired heater chemical cracker.

18. The radiant according to claim 17 , having a length from 50 to 90% of the length of a tube pass in the radiant section of a fired heater chemical cracker a width from ¼ to ¾ of the external diameter of the furnace tube.

19. The radiant according to claim 16 , which is an alloy and has a surface having a thickness from 10 to 5,000 microns comprising from 40 to 60 weight % of compounds of the formula Mn x Cr 3-x O 4 wherein x is from 0.5 to 2 and from 60 to 40 weight % of oxides of Mn and Si selected from MnO, MnSiO 3 , Mn 2 SiO 4 and mixtures thereof provided that the surface contains less than 5 weight % of Cr 2 O 3 .

20. The radiant according to claim 16 , comprising from about 55 to 65 weight % of Ni; from about 20 to 10 weight % of Cr; from about 20 to 10 weight % of Co; and from about 5 to 9 weight % of Fe and the balance one or more of the trace elements.

21. The radiant according to claim 20 , further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % the sum of the components adding up to 100 weight %.

22. The radiant according to claim 16 , comprising from 40 to 65 weight % of Co; from 15 to 20 weight % of Cr; from 20 to 13 weight % of Ni; less than 4 weight % of Fe and the balance of one or more trace elements and up to 20 weight % of W the sum of the components adding up to 100 weight %.

23. The radiant according to claim 22 , further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight %.

24. The radiant according to claim 16 , comprising from 20 to 38 weight % of chromium from 25 to 48, weight % of Ni.

25. The radiant according to claim 24 , further comprising from 0.2 up to 3 weight % of Mn, from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % and the balance substantially iron.

26. The radiant according to claim 16 , comprising an alloy of molybdenum and silica optionally containing boron.

27. The radiant according to claim 16 , comprising a ceramic selected from silicon dioxide, fused silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, thorium dioxide, lanthanum oxide, magnesium oxide, calcium oxide, barium oxide, tin oxide, cerium dioxide, zinc oxide, boron oxide, boron carbide, yttrium oxide, aluminum silicate, silicon nitride, silicon carbide and mixtures thereof.

28. A radiant section of a fired heater chemical cracker having tubes spaced in a pattern where a tube view factor is altered by presence of an adjacent tube, wherein at least one radiant according to claim 1 is positioned proximate at least a pair of tubes to increase the radiant energy directed to the surface of said tubes.

29. The radiant section of a fired heater chemical cracker according to claim 28 , wherein the radiant is vertical.

30. The radiant section of a fired heater chemical cracker according to claim 29 , wherein the radiant is suspended from an overhead mount.

31. The radiant section of a fired heater chemical cracker to claim 29 , wherein the radiant is floor mounted.

32. The radiant section of a fired heater chemical cracker according to claim 29 , wherein the radiant is hung directly from a support used to anchor the coil at a “U” bend.

Assignees

• Nova Chem Int Sa

Inventors

• Petela Grazyna
• Benum Leslie Wilfred
• Crowe Jeffrey Stephen
• Hoseini Seyed Majid

Classifications

• B01J2219/0006

  of the heat exchange medium · CPC title

• C10G9/203 Primary

  chemical composition of the tubes · CPC title

• B01J2219/00166

  controlling the residence time inside the reactor vessel · CPC title

• F28F9/20

  Arrangements of heat reflectors, e.g. separately-insertible reflecting walls · CPC title

• C10G2400/20

  C2-C4 olefins · CPC title