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Delayed Coker Heater Designs

Delayed Coker Heater Designs. TECHNOLOGY — BASICS. Heat Transfer Radiant Convective (Bare, Extended Surface) Combustion Equipment Selection Fluid Flow Coil Configuration In-tube Velocity (Size, No. Of Passes) Refractory Linings Structural Design Mechanical Design.

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Delayed Coker Heater Designs

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  1. Delayed Coker Heater Designs

  2. TECHNOLOGY — BASICS • Heat Transfer • Radiant • Convective (Bare, Extended Surface) • Combustion Equipment Selection • Fluid Flow • Coil Configuration • In-tube Velocity (Size, No. Of Passes) • Refractory Linings • Structural Design • Mechanical Design FILENAME

  3. DELAYED COKER - EXPERIENCE • Over 70 Delayed Coker Heaters Supplied For Over 50 Coker Plants • Single Heater Capacities From 6,000 B/D To Over 30,000 B/D • Single Fired And Double Fired Configurations, To Suit Specific Applications • Designs For A Wide Range Of Conditions And Special Requirements FILENAME

  4. SPECIAL CONSIDERATIONS FOR COKER HEATERS Keep The Coking DELAYED • Single Fired Or Double Fired • Feedstock Characteristics • Flexibility - Investment For The Future • Fuels • Preferences • Heat Input Control • Process Fluid Pass Control • In-tube Velocity • Residence Time • Rising Temperature Gradient • Flue Gas Recirculation in Radiant Section FILENAME

  5. SPECIAL CONSIDERATIONS FOR COKER HEATERS Keep The Coking DELAYED • Optimize Heat Flux Distribution • Coil Arrangement • Symmetrical • Tube Outlet Spacing • Height • Condensate/Steam Injection Points • Optimize Firebox Dimensions • Burner Spacing • Coil Arrangement • Bridgewall or Individual Cells FILENAME

  6. SPECIAL CONSIDERATIONS FOR COKER HEATERS Keep The Coking DELAYED • Temperature (Film & Tube) • Run Length • Constantly Rising Profile • Residence Time • Cleaning The Coil • On-line Spalling • Steam-air Decoking • Pigging • Mechanical - Plug Fittings FILENAME

  7. DELAYED COKER HEATERS Selection Process for Single or Double Fired Delayed Coker Heater Design And Run Length Considerations

  8. FURNACE FOULING d Rf / d = d Rc / d - d Rs / d is rate of fouling d Rf / d Where is rate of coke laydown d Rc / d is rate of coke spalling d Rs / d The rate of coke laydown can be considered a function of: - Characteristics of feed - Residence time - Film temperature - Fluid Velocity The rate of coke spalling can be considered a function of: - Coke characteristics - Fluid velocity FILENAME

  9. TI N2 Supply Line PressureEqualizationLine TI Shell TI Reservoir(Feed) TI Heater Tube Reservoir(Discharge) MeteringPump HOT LIQUID PROCESS SIMULATOR FILENAME

  10. FOSTER WHEELER STANDARD DESCRIPTION Foster Wheeler has established three “standards” for determining the heater configuration 1. 2. 3. Readily fouls and is considered a difficult feedstock for a single-fired delayed coker heater. It has been run commercially with good results in a Foster Wheeler heater utilizing a double-fired design for difficult feeds. This feed is a vacuum residue from a high conversion ebullating bed hydrocracker. Borderline feedstock that tends toward unacceptable fouling. A double-fired design heater is recommended, but a conservative single-fired heater may be utilized with on-line spalling to achieve acceptable run lengths. This feedstock is a conventional asphaltic vacuum residue. Feedstock exhibiting acceptable fouling with single-fired heater. This feedstock is a light, non-asphaltic vacuum residue. FILENAME

  11. FOULING INDEX 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 AREA 1 Readily fouling, Difficult feed. Advanced design heater required. AREA 2 Borderline feed tending towards unacceptable fouling. Advanced design heater recommended or conservative conventional design with on line spalling required. Relative Fouling Index by Deposit Weight (FIDW) AREA 3 Acceptable fouling with conventional heater design. 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 FILENAME Relative Fouling Index by Temperature Difference (FITD)

  12. HEATER RUN LENGTH IMPROVED BY 1. Improved metallurgy 2. Maintaining lower sodium contents 3. Use of on-line spalling FILENAME

  13. Metallurgy Impact on Run Length • Base Material 9 Cr- 1Mo • Design Metal Temperatures to 1300°F • ‘Base’ Run Length • T91 Material • Design Metal Temperature to 1330°F (Old API 530) • Increased Run Length at Expense of Weldability Issues • 347H SS Material • Design Metal Temperatures to 1500°F • Highest Run Length at Expense of Toughness Issues at Return Bends FILENAME

  14. increasing Na+ at constant heater outlet log Na+ increasing 1/ (run length, ) -1 EFFECT OF FEEDSTOCK Na+ LEVELON COKER HEATER RUN LENGTH FILENAME

  15. COKER HEATING FOULING FW-Langseth On-line Spalling procedure is as effective on double-fired furnaces as it is on single-fired coker furnaces operating on easier-to-process feedstocks. FILENAME

  16. Coker Heater On-Line Spalling FILENAME

  17. DELAYED COKER HEATERS CLASSIC SINGLE FIRED DESIGN Horizontal Tube Box or Cabin Heaters

  18. SINGLE FIRED DELAYED COKER - • Optimized Firebox Dimensions • Optimize Heat Flux Distribution • No Flame Impingement • Control TMT Profile • Bridgewall to Control Heat Input to Each Fluid Pass • Symmetrical Piping and Pass Arrangement • Classic Box Heater Fabrication Features FILENAME

  19. DELAYED COKER CHARGE HEATER FILENAME

  20. Peak heat flux is 80% above average heat flux. SINGLE-FIRED COKER HEATERS To ensure long-run lengths and efficient operation, Foster Wheeler incorporates important design features, such as: • Firebox dimensions • In-tube velocity • Burner selection and spacing • Burner testing • Coil spacing • Individual fluid pass controls • Independent firing controls FILENAME

  21. CIRCUMFERENTIAL RADIANT HEAT FLUX DISTRIBUTION – SINGLE FIRED TUBES FILENAME

  22. DELAYED COKER CHARGE HEATER FILENAME

  23. DELAYED COKER HEATERS FWFHD DOUBLE FIRED DESIGN Terrace Wall Design Completely Isolated Radiant Cells

  24. DOUBLE FIRED DELAYED COKER - • Completely Isolated Radiant Boxes • Independently Controlled and Fired Passes • Highly Predictable Flue Gas Flow Patterns • Full Viewing of Tubes • Highly Modular Construction Provided • Shorter Residence Time • Lower Circumferential Film Temperature and TMT • Burner and Coil Viewing Accessible From Grade FILENAME

  25. DELAYED COKER CHARGE HEATER FILENAME

  26. Peak heat flux is only 20% above average heat flux. DOUBLE-FIRED COKER HEATERS • Residence time reduced by half at constant tube velocity and peak film temperature • Optimized coil design: • increase average heat flux to maintain film temperature • reduce coil volume • Features: • High in-tube velocity • Independent pass control • Sloped heater wall for increased flue gas recirculation FILENAME

  27. CIRCUMFERENTIAL RADIANT HEAT FLUX DISTRIBUTION – DOUBLE FIRED TUBES FILENAME

  28. DELAYED COKER CHARGE HEATER FILENAME

  29. DELAYED COKER HEATERS FWFHD DOUBLE FIRED DESIGN Terrace Wall Design Completely Isolated Tube Passes

  30. DOUBLE FIRED DELAYED COKER - • Adds Convection to Radiant Passes in One Box for complete separation of heater passes • Independently Controlled and Fired Passes • Each Pass Can be completely and Individually Isolated • Typical Use is on Two Pass Units with On-Line Spalling and Steam-Air Decoking Capabilities FILENAME

  31. DELAYED COKER CHARGE HEATER FILENAME

  32. DELAYED COKER CHARGE HEATER FILENAME

  33. DELAYED COKER INSTALLATIONS • Over 70 Delayed Coker Heater Furnaces have been supplied for installations around the world including: • BP Toledo 28,900 BBL/D • Shell Oil Deer Park 3@ 26,250 BBL/D • LCR Houston 2@ 23,625 BBL/D • Premcor Pt. Arthur 3@ 28,000 BBL/D • PERM Russia 2@ 22,680 BBL/D • Husky Canada 11,000 BBL/D • Sincor Venezuela 3@ 32,636 BBL/D • Hamaca Venezuela 2@ 33,075 BBL/D FILENAME

  34. Single Fired Design Don’ts • Double row roof tubes • No bridgewalls or bridgewalls too short • Tall radiant coil heights • Tubes to the floor • Upflow process flow in radiant section • Top radiant tube in flow ducts to convection section • Convection tubes tangent to ducts from radiant section • Many tube diameter changes FILENAME

  35. Double Fired Design Don’ts • Staggered row radiant tubes • Roof tubes • Non-Isolated radiant cells • Tall radiant coil heights • Tubes to the floor • Upflow process flow in radiant section • Top radiant tube near flow ducts to convection section • Convection tubes tangent to ducts from radiant section • Many tube diameter changes FILENAME

  36. Revamping and Debottlenecking • Metallurgy Considerations • APH Considerations • NOx and Emissions Requirements • U-Bends Instead of Plug Headers • Enclose U-Bends Inside Radiant Box • Convection Section Modifications • Radiant Box Modifications • Coil Modifications FILENAME

  37. Troubleshooting • Fuel Changes • Organic vs. Inorganic Fouling • Burner Changes and Impact • Feedstock Changes • Increased Preheat Temperature • Velocity Steam Requirements • O2 Readings & Tramp Air Considerations • Draft Control • APH Systems and Heater Balancing FILENAME

  38. BUILDING FIRED HEATERS AROUND THE WORLD FILENAME

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