In the Name of God
Fired
Heaters
BY
Hampa Energy
Engineering & Design Company
(HEDCO)
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Introduction
Combustion
Radiation
Convection
Conduction
Mechanical design
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Introduction
VERTICAL‐CYLINDRICAL FIRED HEATERS
The most common type
Duties up to about 45 MW
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Introduction
HORIZONTAL TUBE CABIN FIRED HEATERS
Not economical under about 35 MW
Duties up to about 145 MW
Rather large footprint
Only for special services
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Introduction
VERTICAL TUBE BOX FIRED HEATERS
Two‐side fired tubes
Suited for the large forced‐draft burners
Steam reformer fired heaters
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Introduction
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Introduction
Heat balance:
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Introduction
Heat balance:
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Burners
Types:
Premix
Raw‐gas
Staged (low NOx)
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Burners
Flame:
Luminous
Non‐luminous
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Radiant section
Radiant heat transfer:
Thermal equilibrium, Kirchoff’s law: 1
Emissivity:
E
, Eblack T 4 (W / m 2 )
Eblack
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Radiant section
Hottel’s well‐stirred model
Simplifications:
Single temperature
Combustion gas is grey Tg
Surface of heat sink is grey
Negligible convection
Speckled wall assumption
TBW Tg
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Radiant section
Refractory:
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Radiant section
Refractory:
Internal insulation
Re‐radiation
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Convection section
Cross flow H.E.
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Convection section
Shield and bare tubes:
2 rows shield tubes
At least 3 bare rows
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Convection section
Extended surface tubes:
Increase H.E. area
Up to 12 times
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Draught
Compensate for pressure drops:
Natural draft
Forced draft
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Tube design
Tube metal temperature
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Tube design
Elastic design:
Elastic allowable stress
Thermal stress
Creep rupture:
Rupture strength for a design life
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Tube supports
Radiant section
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Tube supports
Convection section
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Sketch - A relatively small heater
8 MW start‐up heater
All radiant heater
Vertical tubes
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Sketch-A relatively large heater
25 MW crude oil heater
Horizontal tubes
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Thank You
Tel: (+98) 71- 32136000 Web site: www.hedcoint.com
Fax: (+98) 71- 32136527 E-mail: info@hedcoint.com
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