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A new approach to improving heater efficiency

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  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Reliance Refinery, Jaam Nagar India February 24, 2007 What is this Novel Approach? Typically in a fired heater, the feed is preheated in the convection section and further heated in the radiant section.
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Reliance Refinery, Jaam Nagar India February 24, 2007
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Flint Hills - Corpus Christi, TX 12/01/11
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Valero, Texas City Refinery,TX 12/01/11
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Premcor Refinining Energy Managers Conference February 9, 2005 Furnace Improvements, Low cost solutions for fired heaters
  • Transcript

    • 1. A new approach to improving heater efficiency
        • Ashutosh Garg, Furnace Improvements
      www.heatflux.com
    • 2. Typical Fired Heater Fluid------  Convection section  Radiant section www.heatflux.com
    • 3. Conventional Approach to Efficiency Improvement www.heatflux.com Additional Heat Transfer Surface in Convection Section
    • 4. Split flow Fired Heater www.heatflux.com
    • 5. Typical Reformer Heater
      • Process heated in radiant section
      • Parallel passes, high volume, low pressure drop
      • Convection-Waste Heat Recovery ( HC reboiler or steam generation service)
      www.heatflux.com
    • 6. Split Flow Reformer Heater
      • Process fluid split into two streams
      • Main flow is heated through radiant section
      • Split flow is heated in the convection section.
      • Fluid mixed together at the radiant outlet
      www.heatflux.com
    • 7. Case Studies
      • Citgo Corpus Christi No. 4 Platformer Heater
      • Valero Texas City No. 2 Platformer Heater and NHT heaters (Reboilers)
      www.heatflux.com
    • 8. Citgo, Corpus Christi No. 4 Platformer Heater
      • Objective:
      • Improve Efficiency
        • Stack temperature was 1100 F
      • No steam generation
      • No air preheater
      www.heatflux.com
    • 9. Current Heater Operation www.heatflux.com Parameter Units Operating Value Total Heater Duty MMBtu/hr 158.10 Radiant Heat Duty MMBtu/hr 120.19 Convection Heat Duty MMBtu/hr 37.91 Firing Rate MMBtu/hr 229.20 Efficiency % 68.98
    • 10. Flow Scheme - Before Revamp #4 Platformer Heater www.heatflux.com
    • 11. Existing #4 Platformer Heater www.heatflux.com
    • 12. Proposed Conventional Design High Pressure Drop www.heatflux.com
    • 13. Conventional Design with Series Flow www.heatflux.com
    • 14. Comparison of Pressure Drop at 22,000 BPD www.heatflux.com Pressure Drop, psi Original Design Series flow Design Cell 1 3.1 4.5 Cell 2 3.3 4.6 Cell 3 1.2 2.5 Cell 4 1.1 2.3 Total 8.7 13.9
    • 15. Disadvantages
      • Higher pressure drops
      • Large Size piping
      • Large Convection Sections
      • Higher costs
      www.heatflux.com
    • 16. FIS Split Flow* Scheme * Split flow - US Patent www.heatflux.com
    • 17. FIS Split flow * design - Proposed * Patented. www.heatflux.com
    • 18. Comparison (Cell 1) Parameters at 22,000 BPD www.heatflux.com Parameter Original Design Split flow Design Pressure Drop, psi 3.1 2.1 Firebox temperature, F 1,615 1,551 Radiant flux, Btu/hr ft2 19,823 15,047 Radiant tube metal temp, F 1,151 1,120 Firing rate, MMBtu/hr 116.35 82.65
    • 19. #4 Platformer Heater Data Comparison www.heatflux.com Item Units Before Revamp After Revamp Capacity BPD 18,500 24,000 Heat Duty MM Btu/hr 158.0 194.5 Heat Release MM Btu/hr 234 225 Efficiency % 67.50 86.60 Stack Temp. °F 1,092 478 Fuel MSCFH 244 242.8 Fuel Savings $/annum 5.8 Million* *Based on $6.0 / MM Btu
    • 20. #4 Platformer Heater Before and After Revamp www.heatflux.com
    • 21. Case Study-2
    • 22. Platformer Heaters - Existing
      • Common Convection section with H-18/H-19 and H-23
      • Process heating-all Radiant
      • Steam Generation in Convection
      • Common Stack
      • Natural Draft
      www.heatflux.com
    • 23. Platformer Heaters (H-20/21/22) www.heatflux.com Parameter Units Original Design Total Heater Duty MMBtu/hr 155.98 Radiant Heat Duty MMBtu/hr 74.09 Convection Heat Duty MMBtu/hr 81.89 Radiant Fuel Efficiency % 54.2
    • 24. Plan View of heater www.heatflux.com
    • 25. Convection Section
      • Steam Generator Bank
      • Steam Superheater Bank
      • BFW Preheater Bank
      • Steam Generation: 73,669 lbs/hr@464 psig
      • 14 tubes per row
      • Eighteen rows
      • Two future rows
      www.heatflux.com
    • 26. H-18- Hydrotreater Charge Heater
      • Duty-11.97 MMBtu/hr
      • All Radiant
      • Single pass
      • 5 burners
      • 24 tubes
      • P9 metallurgy
      • 8“ NPS tubes
      • 16” spacing
      • Efficiency -55%
      www.heatflux.com
    • 27. H-19 Hydrotreater Stripper Reboiler
      • Duty-18.45 MMBtu/hr
      • All Radiant
      • Four passes
      • 5 burners
      • 56 tubes
      • CS
      • 4” NPS tubes
      • 8” spacing
      • Efficiency -54%
      www.heatflux.com
    • 28. H-23 Depropanizer Reboiler
      • Duty- 15.15 MMBtu/hr
      • All Radiant
      • Two pass
      • 6 burners
      • 52 tubes
      • CS
      • 4” NPS tubes
      • 8” spacing
      • Duty- 56%
      www.heatflux.com
    • 29. Field Survey
      • High draft in all the radiant cells
      • Burners flame spread out
      • Very high fuel gas pressures
      • Bowed tubes in H-21/H-22
      • Stack dampers are fully open
      • High excess Oxygen in all the cells
      • Burner registers practically closed
      www.heatflux.com
    • 30. Operating Data Simulation Results
        • Convection section was in bad state
        • Fins are burnt out / fouled
        • Steam superheater temperature is 40 F lower than design
        • Thermal Efficiency is 78-81% compared to 88% design.
        • Stack temperature is higher by almost 275 F.
        • Stack temperature ~ 675 F
      www.heatflux.com
    • 31. Conventional Scheme
      • Waste heat recovery( with new convection section retubed in kind )
      • It would not have solved any of the problems linked to over firing of the heaters
      www.heatflux.com Description Units Design Stack temperature °F 404 BFW flow rate Lb/hr 94,000 SSH flow rate Lb/hr 92,120 SSH temperature °F 623 Steam pressure psig 472
    • 32. Split Flow Scheme
      • H-20/H-21/H-22
        • Limit radiant heat flux to 15,000 Btu/hr ft2
        • Shift the balance duty to convection section
      • H-18/H-19/H-23
        • Limit heat flux to 8,000-9,000 Btu/hr ft2
        • Limit the firing to design rate
        • Limit the volumetric heat release to 10000 Btu/ft3
        • Shift the balance duty to convection section
      www.heatflux.com
    • 33. Valero Proposed Revamp – Split Flow Scheme www.heatflux.com
    • 34. Split Flow for H-20/H-21
      • H-20- 3 Bare Rows
      • H-21- 2 Finned Rows
      www.heatflux.com
    • 35. H-18/H-19/ H-23 Revamping Options
      • H-18/H-19/H-23 Heaters
        • All Radiant Heaters
        • Design Efficiency- Low -51-53%
        • Operating Efficiency- 42-52%
        • High Draft
        • Very tight design
      www.heatflux.com
    • 36. H-18/H-19/H-23 Revamping Options
      • Do nothing
        • High firing rates, firing limitation
        • Existing burners may not handle
      • Add convection sections on each heater
        • Good option
        • Expensive
      • Add heat transfer surface in main convection
        • Two rows
        • Economical
      www.heatflux.com
    • 37. Valero Proposed Revamp – Split Flow Scheme www.heatflux.com
    • 38. H-18/H-19/H-23 Split Flow
      • H-18- 8 tubes
      • H-19-12 tubes
      • H-23- 8 tubes
      • Total- 2 rows of tubes
      www.heatflux.com
    • 39. Split flow Convection Section
      • Heat Recovery Sequence
        • H-20
        • H-21
        • H-18 / H-19 / H-23
        • Steam Superheating
        • Steam Generation
        • BFW Preheating
      • Total no. of rows – 20
      • Convection section dimensions unchanged
      www.heatflux.com
    • 40. Proposed Split Flow Revamp
        • Advantages
        • Lower Pressure drop in all heaters
        • Reduce Heat Flux – 15,000 Btu /hr ft2
        • Lower Firing Rate – 203 MMBtu /hr
        • Lower Volumetric Heat Release
        • More efficient system - 88%
        • No civil works
      www.heatflux.com
    • 41. Split flow – Control Scheme
      • Balancing of heat transfer and pressure drop by:
        • Variable resistance (butterfly control valve)
      • Split stream outlet temperature control by adjusting convection section flow
      www.heatflux.com
    • 42. Advantages of FIS Split flow scheme
      • Lower pressure drop (process)
      • Lower firing rate
      • Lower fire box temperatures
      • Lower radiant heat fluxes
      • Lower tube metal temperatures
      • Lesser turnaround time
      • Lower installation cost
      www.heatflux.com
    • 43. Thank you very much
      • Questions and comments are welcome
      www.heatflux.com

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