Delayed Coker Heaters by dffhrtcv3

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									                        Fired Heaters




Delayed Coker Heater Designs




                                        1
                                                   Fired Heaters

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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                                              Fired Heaters

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
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                                                        Fired Heaters

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
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          Flue Gas Recirculation in Radiant Section
                                                Fired Heaters

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
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                                            Fired Heaters

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
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                                     Fired Heaters




DELAYED COKER HEATERS


   Selection Process for Single or
  Double Fired Delayed Coker Heater
       Design And Run Length
           Considerations
                                                     7
                                                                Fired Heaters

FURNACE FOULING
                   d Rf / d    = d Rc / d       - d Rs / d
                                  d Rf / d   is rate of fouling
                 Where            d Rc / d   is rate of coke laydown
                                  d Rs / d   is rate of coke spalling

  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
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                                                                        Fired Heaters
HOT LIQUID PROCESS SIMULATOR

                                                     TI
           N2 Supply Line

                                     Pressure
                                     Equalization                  TI
                                     Line



                       Reservoir               TI              Shell
                        (Feed)
                                              TI           Heater
                                                            Tube




                        Reservoir
                       (Discharge)
                                                    Metering
                                                     Pump


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                                                                     Fired Heaters

FOSTER WHEELER STANDARD DESCRIPTION
             Foster Wheeler has established three
            “standards” for determining the heater
                        configuration
 1.        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.


 2.        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.


 3.        Feedstock exhibiting acceptable fouling with single-fired heater. This
           feedstock is a light, non-asphaltic vacuum residue.
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                                                                                                                                            Fired Heaters
FOULING INDEX
                                                             100
                                                              95       AREA 1
                                                                       Readily fouling, Difficult feed.
           Relative Fouling Index by Deposit Weight (FIDW)


                                                              90
                                                                       Advanced design heater required.
                                                              85
                                                              80       AREA 2
                                                                       Borderline feed tending towards
                                                              75       unacceptable fouling. Advanced
                                                              70       design heater recommended or
                                                              65       conservative conventional design
                                                                       with on line spalling required.
                                                              60
                                                              55
                                                              50
                                                              45
                                                              40
                                                              35       AREA 3
                                                                       Acceptable fouling with
                                                              30       conventional heater design.
                                                              25
                                                              20
                                                              15
                                                              10
                                                               5
                                                               0
                                                                   0    5   10   15 20 25 30         35 40 45 50   55 60   65 70   75 80 85 90   95 100
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                                                                            Relative Fouling Index by Temperature Difference (FITD)
                                         Fired Heaters
HEATER RUN LENGTH IMPROVED BY


  1. Improved metallurgy

  2. Maintaining lower sodium contents

  3. Use of on-line spalling




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                                                        Fired Heaters

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
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                                                 Fired Heaters

EFFECT OF FEEDSTOCK Na+ LEVEL
ON COKER HEATER RUN LENGTH
           increasing Na+
               log Na+




                                                 increasing
                            (run length, ) -1      1/

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                                                 Fired Heaters
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.



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                                           Fired Heaters
           Coker Heater On-Line Spalling




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                              Fired Heaters




DELAYED COKER HEATERS


  CLASSIC SINGLE FIRED DESIGN
        Horizontal Tube Box
               or
          Cabin Heaters

                                              20
                                                 Fired Heaters

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
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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                                                      Fired Heaters

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
                                                Peak heat flux is
           —Burner    testing                  80% above average
           —Coil   spacing                         heat flux.
           —Individual   fluid pass controls
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           —Independent      firing controls                          23
CIRCUMFERENTIAL RADIANT HEAT FLUX DISTRIBUTION –   Fired Heaters

SINGLE FIRED TUBES




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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                                 Fired Heaters




DELAYED COKER HEATERS


 FWFHD DOUBLE FIRED DESIGN
          Terrace Wall Design
    Completely Isolated Radiant Cells


                                                 26
                                                           Fired Heaters

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



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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                                                           Fired Heaters

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:                                         Peak heat flux is
           —High   in-tube velocity                 only 20% above
           —Independent    pass control            average heat flux.
           —Sloped   heater wall for increased
           flue gas recirculation
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CIRCUMFERENTIAL RADIANT HEAT FLUX DISTRIBUTION –   Fired Heaters

DOUBLE FIRED TUBES




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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                                Fired Heaters




DELAYED COKER HEATERS


 FWFHD DOUBLE FIRED DESIGN
          Terrace Wall Design
    Completely Isolated Tube Passes



                                                32
                                                 Fired Heaters

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
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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                              Fired Heaters

DELAYED COKER CHARGE HEATER




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                                                   Fired Heaters

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
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                                               Fired Heaters

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


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                                             Fired Heaters

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
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                                                Fired Heaters

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
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                                             Fired Heaters

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


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                                  Fired Heaters

BUILDING FIRED HEATERS AROUND THE WORLD




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