FiredHeaters 

BY

Hampa Energy

Engineering & Design Company

(HEDCO)

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In the Name of God

Introduction

Combustion Radiation Convection Conduction Mechanical design

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IntroductionVERTICAL‐CYLINDRICAL FIRED HEATERS The most common type Duties up to about 45 MW

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IntroductionHORIZONTAL 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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IntroductionVERTICAL 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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IntroductionHeat balance:

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Introduction

Heat balance:

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BurnersTypes: Premix Raw‐gas Staged (low NOx)

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BurnersFlame: Luminous Non‐luminous

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Radiant sectionRadiant heat transfer: Thermal equilibrium, Kirchoff ’s law:

Emissivity:

1

4 2, ( / )blackblack

E E T W mE

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Radiant sectionHottel’s well‐stirred modelSimplifications: Single temperature Combustion gas is grey  Surface of heat sink is grey Negligible convection Speckled wall assumption

BW gT T

gT

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Radiant sectionRefractory:

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Radiant sectionRefractory: Internal insulation Re‐radiation

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Convection sectionCross flow H.E.

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Convection sectionShield and bare tubes: 2 rows shield tubes At least 3 bare rows 

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Convection sectionExtended surface tubes: Increase H.E. area

Up to 12 times

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DraughtCompensate for pressure drops: Natural draft Forced draft

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Tube design

Tube metal temperature

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Tube designElastic design: Elastic allowable stress Thermal stress

Creep rupture: Rupture strength for a design life

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Tube supportsRadiant 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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www.hedcoint.comWeb site: info@hedcoint.commail: -E

Tel: (+98) 71- 32136000Fax: (+98) 71- 32136527

Thank You

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