Design of Aluminum Holding Furnaces

IE 499

KING SAUD UNVERSITY INDUSTRIAL ENGNEERINGCOLLOGE OF ENGNEERING IE 499

Supervisor Prof. Saied Darwish

B.Sc. Project

By Musaad S. AlSuhibani 422001648

Objective

• The Saudi Aluminum Company is underway. This factory will be operational in a couple of years or more.

• The objective of the present project is to prepare IE students of king Saud university to play then role in crucial projects of their country.

• Aluminium is the third most abundant element in the Earth's crust and

constitutes 7.3% by mass. In nature, however, it only exists in very stable

combinations with other materials (particularly as silicates and oxides) and it

was not until 1808 that its existence was first established.

Introduction

History

• 1808 Sir Humphry Davy (Britain) established the existence of aluminium.

• 1886 Two unknown young scientists, Paul Louis Toussaint Heroult (France) and Charles Martin Hall (USA), working separately and unaware of each other's work, simultaneously invent a new electrolytic process, the Hall-Heroult process.

• 1888 The first aluminium companies founded in France, Switzerland and the USA.

Importance And Properties

• The properties of aluminum that contribute to its widespread use are:

• Aluminum is light; its density is only one third that of steel.

• Aluminum is resistant to weather.

• Aluminum can be used in contact with a wide range of foodstuffs.

•Aluminum is easily worked and formed; it can be rolled to very thin foil.

•Aluminum conducts electricity and heat nearly as well as copper.

Importance And Properties

Application Of Aluminum:

• Transport• Packaging

• Construction

• Medicine

• Electrical

Gulf States and Aluminum Industry:

CompanyProduction (thousand tons)

ALBA (Bahrain)732

DOBAL (Dubi)600

SAHAR (Oman)330-600) 2010(

MADEN (Saudi Arabia)623) 2009(

HYDRO (Qatar)570) 2010(

Alumina production

Alumina Production

• Bauxite has to be processed into pure aluminum oxide (alumina) before it can be converted to aluminum by electrolysis.

production cells

• Two to three tones of bauxite are required to produce one tone of alumina and two tones of alumina are required to produce one tone of aluminum metal.

Types of Aluminum Cells

Type (I) Soderberg with single anode

Type (II) Pre-backed anode blocks.

Holding Furnace

• The holding furnace plays a central role in the fabrication of aluminum. It receives the liquid metal from the electrolytic cells and brings it to the appropriate casting temperature and composition.

• Holding furnaces are usually connected with aluminum smelters to bring the metal to casting temperature.

Kinds of stresses

• Stresses due to furnace and melt weight.

• Stresses consequent to temperature distribution.

Routine Of Finite Element Analysis Involved

• The first step is to implement a heat transfer finite element module for the isothermal lines and temperature distribution.

• The second step is to feed the temperature distribution obtained along with the properties and constrained imposed on the holding furnace to the static analysis finite element in order to obtain the deflected mode of the holding furnace

The Finite Element Program

• The finite element program used throughout this work is named GID.

Boundary Conditions

• Convection boundary condition.

• Radiation boundary condition.

• Conduction boundary condition.

Physical properties of holding furnace construction materials

Materialρ (kg/m3)K(W/m C)C(KJ/Kg C)αE(MPa)ξ

Steel7.87e-635.3458.4812.1e-62.0e50.3

Ref. Concrete0.65e-61.18800.65e-62.10.15

Asbestos3.0e-60.16618803.0e-065.0e-060.15

H.A. Chamotte5.0e-62.511815.0e-63.25e40.15

L.W. Chamotte5.0e-60.16911855.0e-63.25e40.15

Loquid Al.84.18e-624989684.18e-64.0e20.15

Heat Transfer Coefficients Of The Aluminium Holding Furnace

SurfaceAverage

Aluminum Surface

Vertical WallRoof Surface

Inclined Side Wall

InnerOuterInnerOuter

W/m K4.9953.9375.0391.9205.8172.804

CONCLUSIONS

• The numerous interacting phenomena involved in holding furnaces could be simulated in a single finite element model. So, the thermo-mechanical stresses developed can be predicted. This is found to be useful for industry use in case of design or repair of these furnaces.

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