Reboilers - Process Design Practice - Lecture Slides, Slides of Process Engineering

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Distillation Modeling

Overview

Purpose of Reboilers

Provide

vapor

flow

up

a

column

and

acts

as

an

additional theoretical stage below the trays/packing

Types of Reboilers

Thermosyphon

Forced circulation

Kettle

Internal reboiler (rarely used in continuous columns)

Proper reboiler design is critical to the optimum

operation of a column!

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Forced Circulation Reboiler

• Forced circulation reboilers are

designed to operate liquid full.

• Flashing occur as the liquid

crosses the control valve.

• Valve should be located close to

the column shell.

• Forced circulation reboilers offer

greater operational flexibility thanthermosyphons, yet have a smallerfootprint than kettle reboilers.

• Elevation is less critical due to

pump and control valve.

Kettle Reboiler

• Vapor-Liquid disengagement

occurs in the vapor space,therefore return piping is sizedfor all-vapor flow.

• Proper elevation is critical to

kettle reboiler operation.

• Kettles have a large footprint,

but require less elevation thana thermosyphon.

• Works by gravity, rather than

thermodynamics.

Cross Section of

Kettle

All-VaporFlow Region All-LiquidFlow Region

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