The document provides a comprehensive overview of furnace improvement services, highlighting technologies such as inclined burner firing systems that enhance heat transfer and operational efficiency. It covers various designs, including vertical cylindrical heaters and options for low NOx burners, showcasing benefits like reduced tube metal temperatures and uniform heating. Additionally, it details specific case studies demonstrating improvements in thermal performance across multiple heater configurations.

1. Furnace
Improvements
Services
Furnace
Improvements
Services
Uniform Heat Transfer in Fired
Heaters
Furnace Improvements

2. Furnace
Improvements
Services
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Vertical Cylindrical Heaters
 Most Common
Heaters
 Very Compact
Convection
 Low Plot Space
 Low number of
burners
 Economical Design

3. Furnace
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Uniform Heat Transfer
 Minimum
degradation of
process fluid
 No hot spots
 No high tube metal
temperatures
 No coking
 Extended Run
Length

4. Furnace
Improvements
Services
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Radiant Box Design
 Tubes installed in a
Circumference (TCD)
 Burner in the center
 Single burner
provides most
uniform heat
transfer
 Issues with single
burner??
Capacity/Size PLAN VIEW
#1
#2
#3
#3
#4
#4 #5
#1
#2
#5
#6
#6
#7
#7
#8
#8
Ø 21'-7 13/16"

5. Furnace
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Multiple Burners in VC Heater
 Multiple Burners
installed in circle
called BCD
 Multiple burners
take care of the
maintenance
issue/heat release
issue
 Burner to tube
clearance PLAN VIEW
#1
#2
#3
#3
#4
#4 #5
#1
#2
#5
#6
#6
#7
#7
#8
#8
Ø 21'-7 13/16"
Ø 9'-2 3/4"
6'-2 17/32"

6. Furnace
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Low NOx and Ultra Low NOx Burners
 Low NOx and Ultra
Low NOx Burners
being used in heaters
 Larger foot print due
to fuel gas
recirculation and fuel
gas staging
 Flame length and
diameter are larger
 Burners require
minimum spacing for
flue gas recirculation PLAN VIEW
11' 8"
#1
#2
#3
#3
#4
#4 #5
#1
#2
#5
#6
#6
#7
#7
#8
#8
Ø 21'-7 13/16"
Ø 11'-8"
4' -11 13/16"

7. Furnace
Improvements
Services
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Localized Heating
 Heater dimensions are
fixed.
 Burners getting closer
to tubes create localized
overheating of tubes
 Hot flue gas in close
vicinity create high heat
fluxes
PLAN VIEW
11' 8"
#1
#2
#3
#3
#4
#4 #5
#1
#2
#5
#6
#6
#7
#7
#8
#8
Ø 21'-7 13/16"
Ø 11'-8"
4' -11 13/16"

8. Furnace
Improvements
Services
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Uniform heating
 Burners should be as far away from the tubes as
possible
 In conventional heaters it will result in a very large
tube circle diameter
 Larger diameter results in expensive heater design
L.CBURNERS
L.CBURNERS
B.C.D.

9. Furnace
Improvements
Services
www.heatflux.com
Inclined Firing
 Optimum solution for Uniform Heat Transfer
with Ultra Low NOx Burners and VC heaters
Inclined Firing Arrangement
L.CBURNERS
L.CBURNERS
B.C.D.
5° (TYP.)
FIS Patented
Technology

10. Furnace
Improvements
Services
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Benefits of Inclined Firing System
 Significant reduction
in tube metal
temperatures
 Low coking rates
 Higher tube life and
run lengths
 Increased capacity
possible in most
heaters
 Uniform firing
achieved across the
tubes
FIS Patented
Technology

11. Furnace
Improvements
Services
2/25/2015 www.heatflux.com 11
4'
BCD
12'-9"
TCD
12'-9"
INLET
OUTLET
4'
4'-4 ½”
2'-7"
4'
BCD
6'
5'
2'-7"
12'-9"
TCD
Burners are
inclined at
5-10 deg.
Inclined Firing
System
FIS Patented
Technology

12. Furnace
Improvements
Services
Furnace
Improvements
Services
Hot Oil Heater
FIS-392B

13. Furnace
Improvements
Services
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Design Parameters
Process Conditions:
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MMBTU/hr 30.03
Feed Flow Rate Lb/hr 464,006
Feed Inlet/ Outlet Temperature oF 463 / 570
Feed Inlet/Outlet Pressure psia 136.1 / 90
FGT leaving Convection Section oF 544
Thermal efficiency % 85.6
Firing Rate MMBTU/hr 35.55

14. Furnace
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Radiant Section
 48 tubes
• 5”NPS, Sch. 40
 Tube Material
• A-106 Gr. B
 No. of Passes
• 2
 Maximum/Average Heat
Flux
• 17,074/9,413 Btu/hr.ft2
5'-0"
B.C.D.
12'-9" T.C.D.
#
1
#
2
PROCESS
COIL3 BARE
ROWS
3'-10 1/2"
5° 5°
77.9
30.0
CBURNERL
CBURNER
L

15. Furnace
Improvements
Services
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Burners
 6 Natural Draft, Gas
Burners
 Fuel Gas Fired
 Operates at 15%
Excess Air
 Heat release per
burner
• 6.81 MMBtu/hr
(maximum)
• 5.93 MMBtu/hr (normal)
#1
#2
#1
#2
Ø12'-9"
T.C.D.
Ø5'-0"
B.C.D. 3'-10 1/2"

16. Furnace
Improvements
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Hot Oil Heater
 Hot oil heater with 6 inclined burners,
commissioned in July 2014.
FIS Patented
Technology

17. Furnace
Improvements
Services
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Inclined Burners Arrangement
FIS Patented
Technology

18. Furnace
Improvements
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Flue Gas Velocity Contours
Y-Plane
[ft/s]

19. Furnace
Improvements
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Flue Gas Vector Plot
Long recirculation is observed.
Y-Plane
[ft/s]

20. Furnace
Improvements
Services
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Flame Contours (CO >2000 ppm)
Colored by Temperature (o F)
[°F]
Flame shapes are separate from each other.
[°F]

21. Furnace
Improvements
Services
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Flame Contours (CO >2000 ppm)
Colored by height (ft)
[ft]
[ft]

22. Furnace
Improvements
Services
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Tube Metal Temperature Contours
Wall Tubes
Tube Metal Temperatures Flue Gas Temperatures near Tubes
[°F] [°F]

23. Furnace
Improvements
Services
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Wall Tubes Heat Flux Contours
Average Heat Flux on
the Tubes: 10,482
Btu/hr∙ft2
[Btu/hr∙ft2]

24. Furnace
Improvements
Services
Furnace
Improvements
Services
Hydrocracker Heater
FIS-400

25. Furnace
Improvements
Services
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Charge Heater with 6 Burners

26. Furnace
Improvements
Services
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Design Parameters
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MMBTU/hr 45
Feed Flow Rate Lb/hr 414,655
Feed Inlet/ Outlet Temperature oF 554/676
Feed Inlet/Outlet Pressure psia 248/213
FGT leaving Convection Section oF 660-760
Thermal efficiency % 82.5
Firing Rate MMBTU/hr 54.5
Process Conditions:

27. Furnace
Improvements
Services
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Burners
 6 Natural Draft
Burners
 Fuel Gas Fired
 Operates at 20%
Excess Air
 Heat release per
burner
• 11.36 MMBtu/hr
(maximum)
• 9.09 MMBtu/hr
(normal)

28. Furnace
Improvements
Services
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Flue Gas Temperature Contours
Central Plane
[°F]
Temperature
near the
tube is high.
Flame angled
towards the center of
the furnace / away
from tubes.
Existing Case Proposed Modification

29. Furnace
Improvements
Services
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Flue Gas Temperature Contours
Plane
Location
Existing Case Proposed Modification
Temperature
near the tube
is high.
[°F]

30. Furnace
Improvements
Services
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Fluid Path Lines: from Fuel Inlet
Existing Case Proposed Modification
Outer
recirculation
pattern
[ft/s]

31. Furnace
Improvements
Services
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Tube Metal Temperatures
[°F]
Existing Case Proposed Modification
Hot spots due
to flame
impingement.
TMTs more
uniform.

32. Furnace
Improvements
Services
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Radiant Tube Heat Flux
High heat flux
distribution at
bottom of the
tubes
Existing Case Proposed Modification
[Btu/hr∙ft2]
[Btu/hr∙ft2]

33. Furnace
Improvements
Services
Furnace
Improvements
Services
Crude Heater
FIS-356D

34. Furnace
Improvements
Services
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Crude Heater
 Client facing flame
impingement and high
tube metal temperatures
in radiant section
 FIS recommended inclined
burner firing system to
eliminate flame
impingement
 Carried out CFD modeling
of the burners and radiant
section to demonstrate
the benefit of the inclined
burner firing system

35. Furnace
Improvements
Services
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Design Parameters
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MMBTU/hr 261.4
Feed Flow Rate Lb/hr 1,545,460
Feed Inlet/ Outlet Temperature oF 475 / 650
Feed Inlet/Outlet Pressure Psia 134.7/ 34.7
FGT leaving Stack oF 280
Thermal efficiency % 90.5
Firing Rate MMBTU/hr 288.85
Process Conditions:

36. Furnace
Improvements
Services
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Radiant Section
 120 tubes
• 6”NPS, Sch. 40
 Tube Material
• A-335 Gr. P9
 No. of Passes
• 12
 Maximum/Average
Heat Flux
• 18,000/10,000
Btu/hr.ft2
 24 Low NOx Forced
Draft Burners
 Fuel Gas Fired
 Operates at 10%
Excess Air
 Heat release per
burner
• 15 MMBtu/hr
(maximum)
• 12 MMBtu/hr
(normal)

37. Furnace
Improvements
Services
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Existing Burners Arrangement

38. Furnace
Improvements
Services
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Inclined Firing System
Burner Arrangement
FIS Patented
Technology

39. Furnace
Improvements
Services
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Crude Heater: Twin Cell Vertical
Octagonal Type
FIS Patented
Technology

40. Furnace
Improvements
Services
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Velocity Vectors
Base Case vs Inclined Firing System
www.heatflu
40
0 ft
Height in
Feet
19 ft
36 ft
50 ft
[ft/sec]
Existing Case
with Vertically Fired
Burners
Proposed Case
with Inclined Firing
System

41. Furnace
Improvements
Services
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Temperature Contours
Base vs Inclined Firing System
Base Case Inclined Firing System
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41
[°F]

42. Furnace
Improvements
Services
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Temperature Contours at 10ft
Base Case vs Inclined Firing System
Base Case Inclined Firing System
At 10 ft At 10 ft
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[°F]

43. Furnace
Improvements
Services
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Temperature Contours at 15 ft -
Base Case vs Inclined Firing System
Base Case Inclined Firing System
1
At 15 ft At 15 ft
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[°F]

44. Furnace
Improvements
Services
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CO Mass Fraction Contours at 10 ft
Base Case vs Inclined Firing System
At 10 ft
Inclined Firing SystemBase Case
At 10 ft
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44
[ppm]

45. Furnace
Improvements
Services
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CO Mass Fraction Contours at 15 ft
Base Case vs Inclined Firing System
At 15 Ft
Inclined Firing SystemBase Case
At 15 Ft.
www.heatflu
45
[ppm]

46. Furnace
Improvements
Services
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Iso Surface of CO MF 2000 PPM Colored
by Temperatures Base Case vs Inclined Firing
System
Base Case Inclined Firing System
Top View
46
[°F] [°F]

47. Furnace
Improvements
Services
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Iso Surface of CO Mass Fraction
2000 ppm Colored by Flame Height
Base Case Inclined Firing
System
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47
[ft]

48. Furnace
Improvements
Services
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Radiant Wall Temperatures
Base Design Proposed Design
For h =100 Btu/ft2∙h
and T= 800 °F
www.heatflu
48
[°F]
FIS Patented
Technology

49. Furnace
Improvements
Services
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Summary
 Client reported almost 250 °F reduction
in tube metal temperatures after the
revamp.
 Inclined Firing is proven in solving high
tube metal temperatures problems
 CFD modeling demonstrated the ability
of FIS to improve performance
 FIS is ready to evaluate your heater to
determine whether it is a suitable
candidate for Inclined Firing at no cost.
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49

50. Furnace
Improvements
Services
Furnace
Improvements
Services
Hydrotreater Heater
FIS-367C

51. Furnace
Improvements
Services
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Hydrotreater Heater
 Installation of 4 burners in inclined firing
pattern

52. Furnace
Improvements
Services
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Design Parameters
Process Conditions:
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MM BTU/hr 22.5
Feed Flow Rate Lb/hr 188,705
Feed Inlet/ Outlet Temperature oF 600 / 715
Feed Inlet/Outlet Pressure psia 1150.6 / 1104.7
FGT leaving Convection Section oF 773
Thermal efficiency % 79.5
Firing Rate MMBTU/hr 28.29

53. Furnace
Improvements
Services
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DHT Reactor Charge Heater
 23 tubes
• 8”NPS, Sch. 80
 Tube Material
• A-312 TP 347
 No. of Passes
• 1
 Maximum/Average
Heat Flux
• 17,087/9,580 Btu/hr.ft2
4'-8"
I/S INS.
HYDROCARBON COIL
3 BARE ROWS
HYDROCARBON COIL
7 FINNED ROWS
EXISTING
9'-9" T.C.D.
CHEATERL.
4'-0"
B.C.D.
NEW
CBURNERL.
CBURNER
L.
6° 6°
8FT ADDITIONAL
NEW MODULE

54. Furnace
Improvements
Services
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Burners
 4 Ultra Low NOx
Callidus LE-CCQ-8W
Burners
 Fuel Gas Fired
 Operates at 15% Excess
Air
 Heat release per burner
• 7.78 MMBtu/hr
(maximum)
• 7.08 MMBtu/hr
(normal)
4'-0"
B.C.D.
6o
6o
CBURNERL
CBURNERL
FIS Patented
Technology

55. Furnace
Improvements
Services
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Inclined Burners Arrangement

56. Furnace
Improvements
Services
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Contours of Velocity (ft/s)

57. Furnace
Improvements
Services
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Contours of Velocity Vectors (ft/s)
Flow coming from
back of radiant
tubes and going at
bottom of heater
Recirculation loops
are formed

58. Furnace
Improvements
Services
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Contours of Temperature (oF)

59. Furnace
Improvements
Services
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Contours of Temperature (oF)

60. Furnace
Improvements
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Contours of Temperature (oF)
Tube Walls
View -1 View -2

61. Furnace
Improvements
Services
Furnace
Improvements
Services
Solvent Extraction Unit Heaters
FIS-364

62. Furnace
Improvements
Services
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Solvent Extraction Unit Heaters
F-4202 F-4201
⌽1650 ⌽2350
(TYP.)
3°
(TYP.)
5.5°
CBURNER
CBURNER
3200 (P.C.D.) 3962 (P.C.D.)
762 1372
B.C.D. B.C.D.
FLOOR PLT. FLOOR PLT.
L
L
CBURNER
CBURNER
L
L
FIS Patented
Technology

63. Furnace
Improvements
Services
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SEU Heaters

64. Furnace
Improvements
Services
Furnace
Improvements
Services
Inclined Firing in Reboiler Heaters
FIS-329

65. Furnace
Improvements
Services
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Reboiler Heaters
 Two vertical cylindrical
heaters working for
almost 3 years with
Inclined Firing System
 Reduced fouling and hot
spots
 Provided 10% extra
capacity with
Inclined Firing
Technology

66. Furnace
Improvements
Services
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Design Parameters for
HDS Depentanizer Reboiler (004H-102)
Process Conditions:
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MMBTU/hr 51.15
Feed Flow Rate Lb/hr 904,658
Feed Inlet/ Outlet Temperature oF 431 / 456
Feed Inlet/Outlet Pressure psia 178.5 / 162.1
FGT leaving Convection Section oF 510
Thermal efficiency % 85.8
Firing Rate MMBTU/hr 59.6

67. Furnace
Improvements
Services
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HDS Depentanizer
Reboiler Burners
 8 Ultra Low NOx
Callidus CUBLX - 6P
Burners
 Fuel Gas Fired
 Operates at 20% Excess
Air
 Heat release per burner
• 8.65 MMBtu/hr
(maximum)
• 7.44 MMBtu/hr
(normal
CHEATER
&A/DOOR
14'-0 1/4" (T.C.D.)
L
Φ6'-8" B.C.D.

68. Furnace
Improvements
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Design Parameters for
Reformer Depentanizer Reboiler (005H-205)
Process Conditions:
PARAMETER UNIT VALUE
Total Heater Absorbed Duty MMBTU/hr 37.07
Feed Flow Rate Lb/hr 595,799
Feed Inlet/ Outlet Temperature oF 438 / 464
Feed Inlet/Outlet Pressure psia 187.7 / 175.9
FGT leaving Convection Section oF 510
Thermal efficiency % 85.8
Firing Rate MMBTU/hr 43.2

69. Furnace
Improvements
Services
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Reformer Depentanizer
Reboiler Burners
 6 Ultra Low NOx
Callidus CUBLX - 6P
Burners
 Fuel Gas Fired
 Operates at 20% Excess
Air
 Heat release per burner
• 8.36 MMBtu/hr
(maximum)
• 7.2 MMBtu/hr
(normal)
CHEATER
7.5o
L
Φ5'-6" B.C.D.
Φ11'-1 1/8" T.C.D.

70. Furnace
Improvements
Services
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Inclined Burners Arrangement
FIS Patented
Technology

71. Furnace
Improvements
Services
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We hope you found our presentation helpful and informative.
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