ON

REDUCTION PLANT

HINDALCO INDUSTRIES LIMITED RENUKOOT, SONEBHADRA U.P

Guided by: Submitted by:Mr. R.K Yadav Shivam Singh Chandel(Senior Manager) Mechanical EngineeringMr. Abhineet Singh Raj Kumar Goel Institute (Assistant Engineer) Ghaziabad, U. P

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N S

ASSEMBLY POINT

MAIN GATE

ADM.OFFICE

BAUXITE FIRE

COAL TIPPLER

COAL YARD

SEFTY&HRD

FIRST AID

WORK SHOP

Train. Cent.

WASHER

CYOLITE

POTROOM COMP.

AREA

STORE

TO MUD YARD PETROL PUMP

PLANT –I -STORE PROJECT DIV.

GAS YARD

ASSEMLY POINT

LIME PLANT R –DIGESTION BAUXITE TIPPLER

1-ASSEMBLY

2- “

3- “

4-SAFETY OFFICE

5- “

6- “

7- “

8- “ I.T

DEP.

CARBON

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DESIGN OFFICE

DISPOSAL

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CASTER

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B .FURNACE

CAST HOUSE

BULLET

CASTING

PLANT LAYOUT OF HINDALCO INDUSTRIES:

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PRODUCT MANUFACTURED IN HINDALCO:

1. 2. 3.

Primary Aluminium Alloy ingots Bil lets Ingots 4. 5. 6.

Slab Aluminium sheet Wire rods sheet 7. 8. 9.

Door Can Blister Pack

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Table of Contents

1. Preface2. Acknowledge3. Company Profile4. Project Synopsis5. Reduction Plant – II Details6. Crane7. Compressor8. Bath – Crushing9. Alumina Transfer System

(A.A.F.S/H.D.P.S)10. Dry Scrubbing System (D.S.S)11. I.C.M

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PREFACE

In this era of globalization and liberalization of economy, the technology is changing at a swift rate and in this process of revolution one needs to keep up with the world to strive for excellence and to meet the global standards.

Giving this due consideration practical training schedules have been inducted in the curriculum of technical studies as they give a practical exposure to the actual conditions, irrelevant of the field.

In this context I got an opportunity to undergo practical training of 30 days at Hindalco Industries Limited, Renukoot (U.P). During the training I was asked to study about “Reduction Plant- II” in details and it was a great experience for me working on this project under the guidance of the professional’s.

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Acknowledgement

I would like to take this opportunity to express my sincere thanks to Hindalco Management and special thanks to our respected mentor Mr. R. K Yadav (Senior Manager- Potroom Maintenance, for all the guidance and support he provided me while this project was being conducted.

I would like to thanks Mr. Abhineet Singh (Assistant Engineer) for assigning me with the task and the valuable support he has provided to me.

I would also like to thanks Mr. S.K. Das (G.M. Training Dept. Renukoot), and other staff members for their help, support and guidance they provided to us.

I would also like to thanks my maternal uncle Mr. D. K Singh who has suggested me to do training in the worldwide renowned company ‘Hindalco’.

Last but not least I would like to thanks almighty God who has given me strength to perform the task given to me. I would also like to thanks my parents, my sister and brother in law, my teachers and friends and all other member who is directly or indirectly related with this project.

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HINDALCO – It is made by joining three words, when dissolved it comes:

“HIND” – Hindustan,“AL” – Aluminium (Since Al is the chemical formula of Aluminium in Chemistry),“CO” – Corporation

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Lying in the foothills of the Vindhya Range, Renukoot is about 180 km From Varanasi, and 300 km from Allahabad. It is well connected to these cities by beautiful metallic roads passing through green forests.

Phone : (05446) 252077/8/9

Fax : (05446) 0252107Email : hindalco.rkt@adityabirla.com

HISTORY OF HINDALCO:

Hindalco was set up in collaboration with Kaiser Aluminium and

Chemicals Collaboration, USA, in a record time of 18 months. The

plants started its commercial production in the year 1962 with a

capacity of 20,000 tonne per annum (TPA).

The company is managed by Board of Directors, with Shri Kumar

Mangalam Birla as the chairman of the Board of Directors. Day to day

affairs of the company is managed by a team of professionals

Executives headed by Shri Ratan Shah as the Director (Whole Time).

HINDALCO TODAY:

Aluminum has turned out to be the wonder metal of the industrialized

world. No other single metal can do so many jobs, so well, and so

economically.

Aluminum growth rate is the highest amongst the major basic

metals today. HINDALCO ranks as the largest Aluminium producer in

India, whose more than 58% sales is in value-added product and has

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more than 40% in total market share. The company’s fully integrated

aluminum operations consists of the mining of Bauxite, conversion

of Bauxite into Alumina, production of primary aluminum from

Alumina by electrolysis and production of Properzi redraw rods,

rolled products, extrusions and value-added products like Foil and

Wheel at Silvasa. HINDALCO’s integrated operations and

operational efficiency have enabled the company to be one of the

world’s lowest cost producers of Aluminum. The company cost

efficiency has helped it to record on outstanding performance in the

face of adverse market conditions.

HINDALCO also owns a large captive THERMAL POWER PLANT

at Renusagar that meets the power requirement of the company very

effectively.

HINDALCO has embarked upon a Rs 18 billion brown field

expansion project which will Smelter capacity by 100000MTPA,

refining capacity by 210000MTPA, and captive Power Generation to

769MW in the year 2000, HINDALCO acquired Alcon’s 54.6

majority stake in another Indian aluminum major Indal. This was

followed by public offer for an additional 20% stake the

acquisition makes possible and excellent synergistic fit Indal.

Strength in Aluminum and downstream, products dovetail

admirably with HINDALCO strong presence in metal.

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An ISO 9002 and 14001 certified company, HINDALCO achieved

significant export in the year 2001-02 & so on……., and is registered

on the London Metal Exchange. HINDALCO also has star trading

house status. HINDALCO products range includes Primary Aluminum,

Ingot, Alloy Ingot, Billets, Cast Slabs, Alloy Wire Rod, Sheet

Products, Extruded Profiles, Conform Products, Foil and Allow.

HINDALCO POLICY HIGHLIGHT:

Vision

To be a premium metals major, global in size and reach, excelling in everything we do, and creating value for its stakeholders.

Mission

To relentlessly pursue the creation of superior shareholder value, by exceeding customer expectation profitably, unleashing employee potential, while being a responsible corporate citizen

Values

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HINDALCO INDUSTRY – OVERVIEW:

Type ProductIndustry MetalsFounded 1958Headquarters Mumbai, IndiaArea served WorldwideKey people Kumar Mangalam Birla (Chairman)Products Aluminum and Copper productsRevenue 750.77 billion (US$ 12.38 billion) (2013)Operating Income 66.82 billion (US$ 1.12 billion) (2013)Net Income 35.79 billion (US$ 599.19 million) (2013)Total assets 589.32 billion (US$ 9.866 billion) (2013)Employees 19,341 (2013)Parent Aditya Birla GroupWebsite www.hindalco.com

MILESTONE OF HINDALCO:

Year Event1958 Incorporation of Hindalco Industries Limited.

1962Commencement of production at Renukoot (Uttar Pradesh) with an initial capacity of 20,000 mtpa of alumina.

1965Downstream capacities commissioned (Rolling and extrusion mills at Renukoot).

1967Commissioning of Renusagar power plant.

1995Mr. Kumar Mangalam Birla takes over as Chairman of Indal Board.

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1998 Hindalco attains ISO 1401 EMS certification.

1999Brownfield expansion of metal capacity at Renukoot to 242,000 TPA.

2000Acquisition of controlling stake in Indian Aluminium Company Limited (Indal) with 74.6 percent holding.

2001Hindalco enters ‘The Asia Top 25’ list of the CFO Asia Annual Report Survey, the only Indian company in 2001.

2002Amalgamation of Indo Gulf Corporation Ltd. copper business, Birla Copper, with Hindalco with effect from 1 April 2002.

2003

Scheme of arrangement announced to merge Indal with Hindalco

Copper smelter expansion 250,000 TPA.

2007Novelis became a Hindalco subsidiary with the completion of the acquisition process.

2011

Refinance of Novelis debt US$4 billion to lend strategic flexibility to grow.

Achieved financial closure of two projects through debt financing – Utkal Alumina for Rs. 4,906 Crore and Mahan Aluminium for Rs. 7,875 Crore.

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SELF OWNED & JOINT VENTURE COMPANIES OF

ADITYA BIRLA GROUP:

• Around 34000 workforce • 15 + nationalities

Key products and brands Locations Capacities CountryHindalco Industries Ltd. Alumina Chemicals Renukoot (Uttar Pradesh),

Muri (Jharkhand), Belgaum (Karnataka)

1,160,000 tpa India

Primary Aluminium Renukoot, Hirakud (Orissa), Mahan Aluminum

489,000 tpa

Extrusions Renukoot, Alupuram 27,700 tpaRolled products Belur(West Bengal),

Taloja(Maharashtra), Renukoot, Mauda(Maharashtra)

200,000 tpa

Wire rods Renukoot, Alupuram(Kerala) 64,400 tpa

Indal (subsidiary of Hindalco)Foil Rolling

Kollur (Andhra Pradesh) 4,000 tpa

Key products and brands Locations Capacities CountryBirla Copper (Hindalco Industries Ltd.)Copper cathodes Dahej (Gujarat) 500,000 tpa IndiaContinuous cast copper rods 97,200 tpaSulphuric acid 1,670,000 tpaPhosphoric acid 180,000 tpaGold (Birla Gold) 15 mtSilver (Birla Silver) 150 mtDAP&complex(Birla Balwan) 400,000 tpa

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Hindalco Industries Ltd. (Aditya Birla Minerals Resources Pty. Ltd.)Copper cathodes Nifty mines 25,000 tpa AustraliaCopper in concentrate Mt. Gordon mines 40,000 tpa AustraliaPower

Mt. Gordon mines 28MW Australia

Key products and brands Capacities CountryGrasim Industries Ltd.White cement Birla White 475,000 tpa IndiaGrey cement UltraTech

Cement (formerly Birla Plus), Birla Super

13.12 mtpa

UltraTech Cement Ltd. Ordinary Portland cement, Portland Blast furnace slag cement, Portland Pozzolana cement and grey Portland cement

17 mtpa

Key products and brands Capacities CountrySKY INVESTMENT PVT LTDCarbon black Birla Carbon 84000 mtpa IndiaThai Carbon Black Co. Ltd. Carbon black Birla Carbon 220,000 mtpa ThailandAlexandria Carbon Co. S.A.E Carbon black Birla Carbon 285,000 mtpa EgyptLiaoning Birla Carbon Co. Ltd. Carbon black Birla Carbon 55,000 mtpa China

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key products and brands Capacities CountryPulpGrasim Industries Ltd. Rayon grade pulp 70,000 tpa IndiaAV Cell Inc. Softwood / hardwood pulp 122,500 tpa CanadaAV Nackawic Inc.Dissolving pulp 189,000 tpa CanadaFibreGrasim Industries Ltd. Viscose staple fiber (VSF) Birla Viscose 270,100 tpa IndiaThai Rayon Public Company Ltd.VSF Birla Viscose 110,000 tpa ThailandPT Indo Bharat RayonVSF Birla Viscose 155,000 tpa IndonesiaThai Acrylic FibreAcrylic fiber Texlan 100,000 tpa ThailandAlexandria Fiber Company, S.A.EAcrylic fiber 18,000 tpa EgyptYarn

Viscose filament yarn Ray One 16,400 tpa IndiaSKY INVESTMENT PVT LTD (Jaya Shree Textiles)Flax yarns 15,340 spindles IndiaWorsted yarns 25,548 spindlesPT Indo Liberty TextilesRayon yarn, polyester, Blended yarn

45,120 ring spindles Indonesia

PT Elegant Textile IndustryRayon, polyester, rayon-Polyester blended spun Yarn

168,088 spindles Indonesia

PT Sunrise Bumi TextilesViscose rayon, polyester viscose, spun polyester, Polyester combed cotton, anti pill yarn, sewing Thread, high twist yarn, reverse twist yarn, flame Retardant yarn, rayon cotton blended yarn, micro Denier polyester rayon yarn, rayon silk yarn, slub Yarn, lycra core spun yarn

89,376 spindles Indonesia

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Indo Phil Acrylic Manufacturing CorporationHigh bulk acrylic dyed yarn, non-bulk acrylic dyed yarn

3,700 mtpa Philippines

Indo Phil Textiles Mills IncPoly viscose blended yarn, poly cotton blended yarn, Polyester yarn

13,500 mtpa Philippines

Indo Phil Cotton Mills IncCotton yarn 10,000 mtpa PhilippinesIndo Thai Synthetics Co. Ltd. Synthetic yarns 98,568 spindles ThailandFabricsGrasim Industries Ltd. Fabric - polyester, viscose, silk and wool blends 146 looms IndiaUncrushables, Ice Touch, Purista, and CleanFab 18 million metersSKY INVESTMENT PVT LTDPure Linen and Linen Blends

Linen Club 107 looms India

Flame Retardent Fabrics PyroguardBranded apparelSKY INVESTMENT PVT LTD (Madura Garments) Ready-to-Wear Garments Louis Philippe,

Allen SollyVan Heusen, Peter England

India

Key Products and Brands Capacities CountryIndo Gulf Fertilisers Ltd.Urea Birla Shaktiman 864,600 mt IndiaBirla Copper (Hindalco Industries Ltd.) DAP/NPK complexes Birla Balwan 400,000 tpa India

Key Products and Brands Capacities CountryGrasim Industries Ltd.Caustic Soda 258,000 tpa India

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SKY INVESTMENT PVT LTDCaustic Soda 82,125 tpa IndiaLiquid Chlorine 50,340 tpaHydrochloric Acid ,475 tpaTanbac Industries Ltd.Aluminium Fluoride 17,000 tpa IndiaHydrofluoric Acid 17,000 tpaBihar Caustic and Chemicals Ltd.Caustic Soda Lye 92,750 mt IndiaLiquid Chlorine 65,785 mtHydrochloric Acid 29,040 mt Sodium Hypochlorite 1,800 mt Compressed Hydrogen 17,42,400 nm3 Aluminium chloride 12000 tpaCaptive Power Plant 30 MWAditya Birla Chemicals (Thailand) Ltd.Sodium Triployphosphates,Tetrasodium Pyrophosphate,Sodium Hexametaphosphate,Sodium Acid Pyrophosphate,Monosodium Phosphate,Disodium Phosphate,Trisodium Phosphate, Speciality Phosphates

Epoxy Resins (bis-a and bis-f), Diluents, Curing Agents and Allied Products

Sodium Sulphite, Sodium Metabisulphite,Sodium Bisulphate

Epichlorohydrin Caustic Soda Chlorine

Polyphos® EpotecBirlasulf-SS,Birlasulf-SM,Birlasol 35

Thailand

Thai Peroxide Co. Ltd.Hydrogen Peroxide, Peracetic Acid, Calcium Peroxide

Encare, Ecare, Aqua-x, Birlox 5, Birlox 12, Ocare

15,000 mtpa Thailand

PT. Indo Raya KimiaCarbon Disulfide 50,000 tpa Indonesia

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Key Products and Brands Capacities CountryEssel Mining & Industries LtdIron and Manganese Ore 15 million tons India

Key Products and Brands Capacities CountryPan Century Surfactants Inc.Fatty Acids 55000 mtpa PhilippinesFatty Alcohol 30000 mtpaGlycerin 6500 mtpa

Key Products and Brands Capacities CountryAditya Birla InsulatorsInsulators 38,800 tpa India

Key Products and Brands Capacities CountryPSI Data Systems Ltd. (subsidiary of Aditya Birla Nuvo Ltd.)IT solutions (banking, finance and insurance) India

Key Products and Brands Capacities CountryAditya Birla Minacs Worldwide Limited (subsidiary of Aditya Birla Nuvo Ltd.)BPO / ITES 9,089 seats India

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Key Products and Brands Capacities CountryBirla Global Finance Company Ltd.Financial Services IndiaBirla Sun Life Insurance Company Ltd.Insurance Solutions IndiaBirla Sun Life Asset Management Company Ltd.Mutual Funds IndiaBirla Sun Life Distribution Company Ltd.Investment Planning Services IndiaBirla Insurance Advisory Services Ltd.Non-Life Insurance Advisory Services India

Key Products and Brands Capacities CountryIdea Cellular Cellular Services

Idea 21 million subscriber base India

Key Products and Brands Capacities CountryAditya Birla Retail LimitedMulti-Format stores 170 retail outlets India

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REDUCTION PLANT – II DETAILS

Aluminium (Al) is usually produced by decomposing Alumina (Al2O3) dissolved in a bath of molten Cryolite (Na3AlF6) by means of an electric current. The molten mass lies in the Crucible Box lined with Carbon, where the lining acts as cathode. The anode is also made of carbon and is fed down into the molten mass from above. Metal is produced by Alumina being dissolved in the molten salt and

decomposed, thus enabling the Al3+ ions to migrate to the cathode where they are supplied with electrons and they are reduced to elementary metal on contact with the cathode. Point Feeder is used for feeding additives such as Aluminium Oxide or Fluoride to Aluminium electrolysis cells. The additives are fed to the electrolytic bath of the cell through a hole in the bath crust, which hole is made by means of a centre punch.

The process used in Reduction Plant is ‘Hall-Herault Process’. There are two design principles for Hall-Herault Process. Thus, the electrolysis cells can be provided with self-baking anodes, then so called ‘Soderberg Anodes’, which are continuous, or with readily baked anodes of carbon, so called pre-baked anodes, which have to be exchanged during the electrolysis process as they are generally consumed.

The electrolytic bath comprises Aluminium Oxide dissolved in melted Cryolite with the small amount of additives, basically Aluminium Fluoride (AlF3) and Calcium Fluoride (CaF2). During the electrolysis process, the Aluminium Oxide is used as it is decomposed to Oxygen, which immediately reacts with Carbon of the anode, and Aluminium, which due to the gravitational force to the bottom of the cathode. The other additives are to some extent also used, and to maintain the chemical balance in the electrolytic bath, new additives have to be supplied to replace the ones being consumed.

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Potroom Mechanical Maintenance:

• Point Feeder• Fume Treatment Plants ( D.S.S)• Crust Breaker• Crane (Electric Overhead Crane)• Automatic Alumina Feeding System (AAFS)• Belt and Conveyor• General Maintenance

Hindalco Renukoot Unit Is broadly classified into following main plants:-

• Alumina Plant: The raw material, Bauxite (Al2O3.3H2O) is converted to Alumina (Al2O3) by ‘Bayer’s Process.’

• Reduction Plant: Alumina is taken as input and is reduced to Aluminium in Smelter Pots by ‘Hall-Herault’s Process’.

2 Al2O3 + 3C 4Al + 3CO2 (960°C)(Dissolved) (Solid) (Liquid) (Gas)

Aluminium is deposited at cell bottom. Some Al gets dissolved in the electrolyte

• Fabrication Plant: The Aluminium produced in the smelter plant is fabricated into finished goods (like heat sinks, roofing sheets, checkered sheets etc.) or semi-finished goods (like coils, wire rods, circles etc.).

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CRANE

• Crane: It is equipment used for material handling in the industry and organization.

• Types of Crane: It is basically of three types:-

1. Electric Overhead Travelling (E.O.T) Crane.2. Mobile Crane (e.g. Fork Lift).3. Jib Crane.

• In Hindalco Industries, Electric Overhead Travelling (E.O.T) Crane are widely used.

• E.O.T Crane:

The crane moves on the gantry rails, fixed on top of the gantry girders. In this type generally three motions are incorporated, namely Hoist, Cross Traverse and Long travel. At times according to the customer’s requirement Auxiliary Hoist and micro motion are also incorporated. The Hoist and Cross travel machineries are fitted on a common frame called the “Crab or Trolley” which moves on rails fixed on the Crane Girders.

• Main Parts of the E.O.T Crane:

1. Long Travel (Bridge): This type of crane travel takes place in horizontal direction for over a long distance.

2. Cross Travel (Trolly): This type of travel takes place on crane to move load from one end to other on crane itself.

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3. Hoist Travel (Hoist): This type of travel is used for uplifting and lowering of load vertically upto a desired height (not more than 12.8 meter).

• According to Bridge Drive:

1. Single Motor Drive Crane.

2. Double Motor Drive Crane.

• Major Parts of E.O.T Crane:

1. Long Travel Drive Mechanism.2. Trolly Assembly.3. Bridge Girders.4. End Carriages.5. Platforms.6. Operator’s Cabin.7. Trolly Power Supply Arrangement.

• Advantages of E.O.T Crane:

1. They eliminate the need for wide passages and do not block any space at ground level.

2. They cover the entire working area without limiting the layout.

3. Operating costs are very low, since it needs only one operator, require very little maintenance and consumes a very little electric power.

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• Brakes in E.O.T Crane:

1. Bridge : Foot Operated Hydraulic Brake.2. Trolly : NIL.3. Hoist : D.C Electro Magnetic Brake.

• Safe Working Load (S.W.L) of E.O.T Crane:

Weight: 7.5 Metric Tonne Height: 12.8 Meter

• Power Supply In Crane:

415 Volt 3 Phase Power SupplyCrane moves on ‘Current Rail Path (C.R.P)’.

• The following are the given capacity and drive of cranes fitted in various lines of Reduction Plant:

Pot Line Makers Safe Working Load

Drive

Line 1 P & H 6.0 MT Single DriveLine 2,3 P & H 7.5 MT Single DriveLine 4 A.C.C 7.5 MT Single DriveLine 5 W.M.I 7.5 MT Double DriveLine 6 to 11 MUKAND 7.5 MT Double DriveB/F # 1 to 3 W.M.I 6.0 MT Double DriveB/F # 4 CIMMCO 6.0 MT Double DriveMaintenance W.M.I 7.5 MT Single Drive

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Area

• To avoid electric spark in Potroom Cranes, Hook insulator in bottom block assembly are used. So ‘Thrust Ball Bearings’ are used in Hook Insulator.

• Hoist Maximum Lift:

1. Line 4 5.0 MTR.̶2. Line 5 to 8 5.8 MTR.̶3. Line 9 to 11 6.1 MTR.̶4. B/F # 4 4.9 MTR.̶

Wire Rope:

• Wire Rope Material: Ungalvanized Steel.

• Wire Rope Construction:

16 mm is diameter of one string of wire.19 string is aligned together to make one core, and6 core combines together to form one wire rope.Length of wire rope varies from 38 – 48 MTR, depending on use.

Line 4 16 mm Diameter * 6 * 19 * 38 MTR̶Line 5 to 8 16 mm Diameter * 6 * 19 * 42 MTR̶Line 9 to 11 16 mm Diameter * 6 * 19 * 48 MTR ̶B/F # 4 - DO -̶Maintenance Area 16 mm Diameter * 6 * 19 * 38 MTR̶

• Ultimate Tensile Strength ̶ 180 MPa.• Breaking Strength 16500 kgs. ̶

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Hook Material:

Fully Killed Low Carbon Steel EN – 3ASIS; 1875 Grade 2

1. Original opening of hook is 78 mm (allowable opening of hook is 10%of the original opening =7.8mm. so max. hook opening 85.8mm is allowable)

2. hook thickness is 105 mm (max wear is 10% i.e.10.5mm allowable)

Pot Room Crane Speed:

• Bridge Speed : 122 MTR/MIN• Trolley Speed : 58 MTR/MIN• Hoist Speed : 12.8 MTR/MIN

Procedure to Start the Crane:

1. Check Crane and craneway for any obstructions.

2. Release all ‘locking device’.

3. Check that parts needing lubrication have required quantity of lubricants.

4. Ensure that no item is lying loose on the crane and the trolly.

5. Check for neutral position of all ‘control gears’.

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6. Switch on the ‘Crane protective gear’.

7. Check signals and wiring devices.

8. Check ‘brake and limit switches’ for their proper functioning.

Procedure to Stop the Crane:

1. Run empty hook and the trolly to the specified resting position.

2. Run Crane to the access point.

3. Set the ‘master controllers’ in neutral position.

4. Switch off lights.

5. Press the OFF push button provided in the cabin/pendent.

6. Switch OFF the isolating switches.

7. Actuate locking devices if any.

8. Lock ‘Operator’s cabin’.

Precautions on Use of Crane:

1. Make sure of the operation of safety device before hand.

2. Do not load beyond the ‘safe working load’.

3. Do not use crane beyond it’s designed ‘duty cycle’.

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4. Do not use Crane in lower notches of master controller for long period.

5. Do not use creep speed for continuous/long operation. The creep speed is only for spotting the load.

6. Avoid quick ‘deceleration’.

7. At the end of shift, inspect the crane and prepare for the next shift.

More details about E.O.T.Crane maintenance :

Wheel Wear

Due to presence of aluminum in the atmosphere the wear on the wheel

tread is rather fast. Whenever there is wear, the worst about it is that

there is unequal wear on specially the two side driving wheels. This

results in unequal diameter on two sides of the crane. If a crane with

unequal diameters diameter runs, it is likely to get tilted. As a distance

covered increases the tilt also would increase but, the crane runs on

wheel collars and this result in undue collar wear. The tilting of crane

is called “Crossing of Crane”.

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Reason For Crossing of Cranes Leading

To Frequent Shoe Out :

1. Unequal wheel wear specially in lines 1,2,3 and 4 where we have single motor drive. Wherever there is a wear, it is unequal wear and there is crossing of the crane. We have seen that difference of more than 1.5 mm causes jamming, shoe out etc. due to crossing of cranes.

2. Loose driving shaft keys/keyways or excessive play in the geared couplings will cause jerky start on one side and causes crossing of the cranes.

3. Excessive dusting in the pot room also causes crossing of the crane.

4. Damaged bearings of the bridge drive gear box causes crossing of the cranes.

5. Defective rail or rail joint with unequal gap at to ends may cause crossing of the cranes .difference in heights of the rail at the joint may also cause crossing of the cranes.

6. Failure of the rail /crane girder holding to the main roof columns causing the crane girder to bend horizontally or vertically may also lead to crossing the cranes.

7. Misalignment of the wheels may also leads to crossing of the cranes. The problem is most when the wheels are changed for maintenance purpose.

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General Checking In Pm:

• Oil Level, Oil Leakage & Base Bolt Of Gear Boxes • Brake Drum & Brake Unit Of Hoist & Bridge• Foot Brake (Master Cylinder)• Wheels, Bearing & Housing• Base & Coupling Bolt Of Motor• Coupling & Coupling Bolts Of All Shaft• Rope Drum & Rope• Bumper Block & Stopper• Hoist & Bridge Lever & Controller• Base & Coupling Bolt Of Motor• Coupling & Coupling Bolts Of All Shaft• Rope Drum & Wire Rope (If 10 Wire Broken In 01 Ft Of 6/19 Wire

Rope)Then Wire Rope Should Be Changed • Hoist & Bridge Lever & Controller Pantograph/Shoes & Flexible

Main Problems occurred in the Crane:

1. Current Rail Path (C.R.P) Tripping Trouble.

2. Collector Shoe out Trouble.

3. Bridge Jamming Trouble.

4. Hoist Brake Slipping Trouble.

5. Foot Brake Trouble.

6. Wire Rope Sparking.

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7. Hook Insulator Sparking Trouble.

8. Hook Jamming Trouble.

9. Wire Rope Broken Trouble.

10. Trolly Derailment.

Cause of C.R.P Trouble:

1. Collector Shoe out.

2. Defective C.R.P Joints.

3. Crossing of Crane.

4. Misalignment of Pantograph.

5. Defective Track Rail Joints.

Some Important information regarding Crane:

• We change ‘roller wheel’ of Crane with the help of jack.

• The material used in roller wheel is of ‘Mild Steel’.

• ‘Slip Ring Induction Motor’ is used to drive the rope attached with hook.

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• Every motor of a Crane has a specific designation by which it is differentiated.

e.g 15 C 300

15 – Horse Power. C – Pole. 300 – Motor Number.

• In Hindalco industries the motor used is of ‘C Pole’.

• When Motor has some problem then for its repairment it is send to ‘Electrical Repair Shop (E.R.P) Department’.

• In E.O.T Crane 4 wheels are mounted.Two wheels are ‘Supporting Wheel’.Two wheels are ‘Idler Wheel’.And Power is always given to Idler Wheel.

• Formula to calculate the speed of motor:Speed (N), rpm = 120 * f/PWhere, f = frequency, (50 Hz) P = Number of Poles (6)

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Some Important Questions related to Viva and Interview:

• Why only D.C Electromagnetic Brake is applied on Hoist Travel, why not A.C?

∗ We all know that Alternating Current (A.C) is in pulsed form and it has variations, sometime it is positive for short time it is zero and then negative. This will lead to the up and down motion of hook even after application of brake which can cause serious injury and accidents in industry, so this is reason why we use Direct Current (D.C).

• How does E.O.T Crane moves?

∗ In Crane no any wire is attached then also it moves and this is possible due to ‘Current Rail Path (C.R.P)’ which have three phase and is attached with platform and provide it supply of current on which Crane moves.

• What are Lubricant applied in Wire Rope and Roller Wheel?

∗ ‘Servomess 175’ lubricant is used in Wire Rope.‘Grease’ is used as lubricant in Roller Wheel.

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COMPRESSOR

• Compressor supplied to Hindalco Industry is by ‘K.G KHOSLA Compressor Limited’.

• Intercooler: Pipe Length – 135 cmPipe Outer Diameter – 192 m/mPipe Inner Diameter – 185 m/m

• Aftercooler; Pipe Length – 135.7 cmPipe Outer Diameter – 252 m/mPipe Inner Diameter – 237 m/m

General Description:

‘KHOSLA – CREPELLE’ air compressors are of double acting horizontal crosshead type and are built in one, two and three rows. Each row consists of two opposed cylinders. The compressor is driven by an ‘Electric Motor/Diesel/Turbine’ through V-Belts or Direct drive.

Each row has two crankpins arranged at 180°. This type of compressor is balanced because two pistons of each row move in opposite direction. The primary and secondary component forces nullify each other and suppress all possibilities of vibration. The efforts of each opposing crankpin are equal and create an axial couple without reaction on the bearings.

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INTRODUCTION:

∗ Compressors are machines designed for compressing air or gas from an initial intake pressure to a higher discharge pressure.

APPLICATIONS: Compressors are used in wide variety of applications as follows:

• For operating Instruments• For operating Pneumatic Tools, gates, damper through• Pneumatic cylinder.• It is substitute for Steam, electricity in operating tools, drills etc.• For agitation of Liquid in tanks.• For burner firing through atomization.

CLASSIFICATIONS OF COMPRESSORS:

1. Reciprocating 2. Rotary Vane3. Screw 4. Turbine 5. Centrifugal

∗ Single Acting, Double Acting, Single Stage, Multi stage, Two Stage, Single Cylinder, Multi Cylinder, Water Cooled, Air Cooled, Electrical, Diesel, Gas, and Steam.

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AIR FLOW IN RECIPROCATING COMPRESSOR

L.P. Cylinder

L.P. Piston

Piston Rod

Crank Shaft

Cross Head

Connecting Rod

Crank Case

H.P. Cylinder

H.P. Piston

Inter Cooler

MAIN PARTS OF RECIPROCATING COMPRESSORS:

• Crank Case: Heavy duty grain cast iron frame. It also serves as lubricating oil reservoir.

• Crank Shaft: Made of drop forged steel is provided with bolted counter weights.

• Connecting Rod: Made of nodular gray iron or forged alloy steel and are provided small & big end bearing.

• Cross Head: Made of nodular gray iron and is designed to ensure true running of piston rod.

• Cylinder: Made of graded close grain cast iron. These are provided with water jackets to ensure efficient cooling of the surface that comes in contact with hot compressed air.

• Piston: Made of nodular gray iron or high grade aluminum alloy & having the same weight i.e. L.P Piston hollow & H.P Piston solid.

• Oil Pump : Gear pump is driven from the free end of crank shaft for lubrication of parts.

• Inter Cooler : It is device for removing the HEAT OF COMPRESSION of the air between consecutive stages of multistage compressors.

• After Cooler: These are meant for removing the heat of compression of the air after Compression is completed. These are also used for removing moisture from compressed air.

• Air Receiver : It is used to store the air and help to eliminate pulsation in the discharge line.

• Valves: Each cylinder is provided two suction & two delivery valves for the upper and lower compression. The Valve is opened and closed by means of the pressure difference occurring in the cylinder.

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Details of Equipment:

1. Name of Equipment – KHOSLA Compressor (1 No to 6 No).2. Year of Installation – 1991.3. Manufacturer – M/S K.G KHOSLA Comp. Ltd.4. Capacity/Speed – 1070 CFM/970 RPM.5. Model – 2 HA 4 TER.6. Type – Reciprocating Horizontal Balanced7. Discharge Pressure – 7.0 kg/cm2.8. Load/Unload Pressure – 4.5 kg/cm2, 6.0 kg/cm2.9. Inter Stage Pressure – 1.2-2 kg/cm2.10. Intercooler/Aftercooler – Water from shell, Air from Tube.11. Low pressure cylinder diameter – 310 mm ¢ * 2.12. High pressure cylinder diameter – 185 mm ¢ * 2.13. Piston Ring Quantity (L.P) – 02Cast Iron.14. Piston Ring Quantity (H.P) – 03Cast Iron.15. Cylinder/Valve – Lubricated.16. Oil Used – Servosystem – 121.17. V-Belt Size/Quantity – D-238/11 Nos.18. Motor Power/ Motor Speed – 250 H.P./1400 R.P.M.19. Motor Type – Induction.

∗ CFM – Cubic Feet per Minute.R.P.M – Revolution per Minute. *

Single Stage Compressor:

Each cylinder is fitted with ‘suction and delivery valve’. The suction air filters are mounted on both the cylinders, so that air can enter at both ends of the piston during the forward and backward stroke. As the piston is moving in the cylinder, quantity of air sucked at the front side is compressed to the required pressure when the piston travels towards the front end cover and

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similarly when the piston moves towards the rear end of the cylinder.

After compression the air passes to the header (if fitted), through the delivery valve. The header works as an auxiliary air receiver, thereby the temperature of air is reduced to some extent and pulsations are damped. Finally, air passes to air receiver or delivery pipe line.

Two Stage Compressor:

After compression, the air from the first stage cylinder passes through delivery valve to the water cooled heat exchanger provided in between the first and second stage. There it is cooled very near to the atmospheric temperature and is sucked by the 2nd

stage through the suction valves. In the second stage cylinder the air is compressed again to the required pressure and then to the Aftercooler, if provided and finally to the air receiver.

In compressor having more than two stages the air from the second stage enters the next intercooler and a similar operation as stated above is repeated till the air reaches to the final stage. It is passed to the Aftercooler, if provided and finally to the air receiver.

Centrifugal Air Compressor:

The ‘Centac Compressor’ is designed to provide oil free compressed air. The atmospheric air being compressed via suction filters enters the compressor through the machine mounted inlet control device and flow to the first stage where impellor imparts velocity to the air. The gas proceeds to the stationary diffuser section that converts velocity to pressure. The built in air cooler removes the heat of compression and the air

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then passes through the moisture separator in a low velocity zone to remove condensate. This process continues in all subsequent stages.

DESCRIPTION:

The Centac compressor is a centrifugal compressor driven by an electric motor. The compressor and driver are direct coupled.

The Compressor Contains:• A main driver that directly drives a bull gear that is common to

all stages.• Compression stages consisting of an impeller mounted on its own

shaft, enclosed with in a common cast iron casing.• Rotors consisting of an integral pinion gear driven at its optimum

speed by a common bull gear.• An intercooler that is mounted after stage of compression.• A moisture separator and a moisture removal system are fitted

after each cooler to remove condensate.

CENTAC Compressor Details:

1. Manufacturer – Ingersoll Rand (I) Pvt. Ltd.2. Number – Comp # 20, 21, 22.3. Equipment – “CENTAC” Centrifugal Compressor.4. Model – C55MX3EXT.5. Drive – Electrical Motor.6. Stage – Three.7. R.P.M – Stage 1– 39,000, Stage 2 – 44,0008. Type – Centrifugal.9. Capacity – 6092 CFM.10. Discharge Pressure – 7.0 kg/cm2.

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11. Intercooler/Aftercooler – Air through Shell, Water through Tube.

12. Tube Specification – Copper, with 5/8” O.D * 18 DWG.13. Type of Lubricant – Servoprime-32.14. Oil Pump (2 Nos) – Pre oil pump & Main Oil Pump.15. Air Filter – Primary, Secondary (6 Nos.).

Motor Side:

1. Manufacturer – BHEL (Bhopal).2. Frame Size – 1LA 7636-2.3. Applicable Standard – IS 325-1978.4. Type – Induction Motor.5. Service – Outdoor.6. Duty Cycle – Continuous.7. Rated Power – 950 kW.8. Ambient Temperature – 55°C.9. Rated Speed – 2978 R.P.M.10. Rated Voltage – 6600 V ± 10.11. Rated Frequency – 50 Hz ± 5.12. Full Load Current – 96.6 Ampere.13. No Load Current – 21.9 Ampere.14. Efficiency – 95 %.15. Total Weight – 5300 kg.

Compressor Operating Parameters:

1. Inlet Cap – 6092 ICFM.2. Discharge Pressure – 7.0 kg/cm2.3. Discharge Pressure Oil Filter – 0.3 to 0.8 kg/cm2.4. Seal Air Pressure – 0.5 to 1.8 kg/cm2.5. Instant Air Pressure – 4.2 to 8.4 kg/cm2.6. System Oil Pressure – 1.8 to 2.1 kg/cm2.7. System Oil Temperature – 43°C to 46°C.

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Cooling Water:

1. Pressure – 2.5 to 5.0 kg/cm2.2. Temperature – 28°C to 30°C.3. Pressure Drop, Temperature Rise – 0.7 kg/cm2, 8.3°C.4. Vibration Stage – 0.05 to 0.50.45. Stage 3rd Temperature – 40°C ± 10.6. Motor Wind, BRG Temperature – 90°C ± 10, 70°C ± 10.

Compressor Parts:

• Rotor Assemblies• Bearing• Seals• Diffusers• Intercoolers• Moisture Separators• Vibration Probes• Casing• Compressor Driver• Lubrication System

1. Diffusers: A diffuser, located between each impeller and cooler, converts velocity energy to pressure energy.

2. Intercoolers & After coolers: The coolers are donut type, with water over tubes and oil in shell.

3. Moisture separators: The moisture separator is a SS mesh screen type construction located at points in the air compressor where air velocities are relatively low permitting efficient moisture separation.

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4. Vibration Probes: A non contacting vibration probe is mounted on each stage next to the plain bearing to measure vibration of each rotor assemblies. Each probe is connected to a vibration transmitter.

5. Casing: The gear case consists of a casing and casing cover jointed vertically by bolted assembly which is opened for servicing the bull gear and its bearings.

6. Rotor Assemblies: Each rotor consists of an SS impeller and a removable thrust collar mounted on a helical geared pinion shaft each secured to the shaft by polygon splines, eliminating the need of keyways.

7. Bearings: Each rotor assembly is equipped with a thrust bearing near impeller and a plain journal bearing, Babbitt lined, near bull gears for radial loads.

8. Seals: A single cartridge seal is mounted in the plain bearing house behind each impeller. Each cartridge consists of three, one piece, fully floating non contact carbon rings. One ring is used as an air seal and the remaining two as oil seals. Buffer air is supplied to the oil a seal assuring that lube oil is not drawn past the seals, thus ensuring oil free air.

Compressor Efficiency:

∗ Factors effecting the Compressors efficiency:

• Leaky Valve• Too large piston ring gaps• More clearance between cylinder and piston• Leakage at piston rod• Inadequate inter stage cooling ( inter cooler plugged)• High Inlet air temp.• Low water pressure• High inlet water temp. • Speed is less ( Prime mover)

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• Chocking of Suction filter• After cooler ineffective • Moisture separator is not working properly ( moisture in air)

Air Conservation/Efficient Air System:

• Inter cooler & after cooler must be perfect and to be cleaned periodically.

• Threaded connections are to be avoided in air system.• Tapping in air lines, receiver outlet should be from top to avoid

water moisture carry over.• Auto drains are to provide for drain.• Globe valves should never be used in air system as pressure drop

is very high. In 1” ø gate valve pressure drop is 1.14 ft of used pipe where as in 1” ø globe valve is 30 ft of used pipe.

• Hydraulic testing of Receiver should be done on every year at 1.5 times the safety valve setting.

• Flow meters are to provide in air lines to control the air consumption.

• The co lour coding of air lines are essential.• Cleaning operation should be done with 30-40 psi air pressure

only to save air consumption. Pressure regulations are to be provided.

• 1/2” ø pipe releases 308 cfm at 70 psi• 1/2” ø pipe releases 200cfm at 40 psi• Efficiency, flow measurement of compressors.

Ratio of Compression : The rates of initial volume to the final volume.

∗ Cylinder Ratio: r = P3 / P Where r = Ratio of Compression

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P3 = Absolute discharge pressure in psi P = Atmospheric pressure in psi

∗ Inter Cooler Pressure : P1 = P X P3 / P – P

∗ Pressure Drop in Line: LV2

R x d5.3 x 35000

L = Length of Pipe in ft, V = Volume of free Air in CFMR = Ratio of Compression, d = I D Of Pipe in ft

∗ Piston speed: 2 x Stroke length x rpm ; 12 Ft/min ∗ Displacement: It is the volume swept through by the piston with

proper deduction for the piston rod, Unit -CFM.• Normal velocity in compressed air piping = 20 ft/ sec Max.

∗ Effect of Comparative pressure on Power Cost - Cost of air generation is 7 % less at less at 6 kg / cm2 than at 7 kg / cm2.

∗ Unloading Power of compressors in comparison to full load :

Unloading Power consumption should be 15 % to 18 % of full load.• Cost of air generation in Alumina Plant Rs. 5. 20 approx.

(Calculated.)• Intake air temp. Decreases 3 degree C & due to this increase in

volume delivered by 1 %.

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Procedure to Start the Compressor:

1. Check that cooling water valve is opened.

2. Check for cooling water inlet pressure to be in between 2.5 kg/cm2 to 5.0 kg/cm2.

3. Check for the difference in between inlet and outlet cooling pressure and that should lie in between 0.8 kg/cm2 to 1.0 kg/cm2.

4. ‘Sealed air pressure’ should be approx 0.5 kg/ cm2.‘Instrument pressure’ should be in between 4.25 to 8.5 kg/cm2.

5. Check level of oil in oil receiver and ‘Motor Bearing Indicator’.

6. Start pressure lubrication pump with the help of ‘control button’ and maintain oil pressure near about 2.0 kg/cm2.

7. Oil temperature should be in between 35°C to 50°C.

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8. Ensure that inlet valve is closed and ‘bypass valve’ is in open stage and drain moisture with the help of ‘Moisture Drain Valve’.

9. With the help of ‘Start Push Button’ start the compressor in unload direction and ensure that oil pressure and temperature is correct.

10. In every stage check ‘bypass’ situation and with the help of ‘load push button’ bring compressor in load condition.

11. At every cooler note the temperature of water and ensure that in between inlet and outlet, temperature difference should not be greater than 8.0°C.

12. Check the flow of ‘discharge air’ from the compressor.

Procedure to Stop the Compressor:

1. With the help of ‘unload push button’, unload the compressor.

2. With the help of ‘stop push button’, stop the compressor and hold it in the same condition for 20 to 30 minute.

3. With the help of ‘control button’ stop control supply and with inlet-outlet valve, stop the supply of water.

Some important questions related with Viva and Interview:

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• What will happen if air is not cooled in intercooler and is directly ejected in ‘High Pressure (H.P) Cylinder’?

∗ Air (atmospheric) is at pressure of 1.0168 bar and it in ‘Low Pressure (L.P) Cylinder’ is converted into 1.5 bar. Due to increase in pressure the gas become hot and its temperature also get increased, and we know the property of hot gas that it expands and cover a large volume. When this hot air is directly ejected into the H.P Cylinder the piston and piston rod will become hot and more lubrication will be required and tendency of compressor to produce ‘plant air’ will be decreased and hence the efficiency of compressor will also decrease.

• If the pressure in H.P Cylinder will not lie in Safe Working Level (5 kg/cm2 to 7 kg/cm2) i.e. it will increase or decrease then what will happen

∗ If this condition arises the ‘mechanical governor’ is fitted which will do loading and unloading of compressor. If the pressure is below 5 kg/cm2 then ‘unloading’ of compressor will take place and if pressure is more than 7 kg/cm2 then ‘loading’ of compressor will take place.

BATH CRUSHING

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• In ‘Bath - Crushing’ the medium block of ‘Cryolite (Na3AlF6)’ is crushed in powdered form (generally below 19 mm diameter) and is mixed with ‘Alumina powder’ and is sent to Potroom for extraction of Aluminium metal.

• Cryolite is used to produce and maintain heat in pot.

• ‘50 HP Induction Motor’ is used to break the ‘Bath’ by rotating ‘Rotary Breaker’.

9 * 15 Rotary Breaker:

The Model Number 9 * 15 Rotary Breaker is derived as follows:

9 – 9 feet diameter (2745 mm) at the screen plates15 – 15 feet internal length (4575 mm)

This 9 * 15 Rotary Breaker consist of a ‘Barrel’ supported on ‘Trunnion Rollers’. The Barrel is lined with perforated ‘screen plates’ and is driven by a ‘Chain Drive Arrangement’.

The principle function of Rotary Breaker is as follows:

a) Break and separate the material through lifting and impacting inside the Rotary Breaker, the impact reducing the material size to allow to sized material to filter through screen plates.

b) The material not able to be broken, drown to pass through the screen plates, unprocessed material is discharged through ‘refuse chute’ and disposed, this operation requires the Barrel to be rotated in the reverse direction.

9 * 15 Rotary Breaker Equipment Data:

Duty: a) Capacity 40 M.T nominal

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b) Material

c) Feed Sized) Discharge Size

Aluminium Oxide, Cryolite, Aluminium400 mmMax. Size < 22 mm

Machine Data: a) Gear Box Ratiob) Breaker Drive

c) Drive Motord) Breaker Speede) Coupling Type

13.5:13.5” Pitch Drive ChainSupplied by Others16 R.P.MFluid Coupling

Machine Dimensions:

a) Overall Lengthb) Overall Widthc) Heightd) Overall Mass

6650 mm5410 mm3985 mm44,480 kg

Serial number:

Mc Lanahan Reference:

20053100

B 040308:01

Rotary Equipment Installation and Alignment Procedure:

1. Inspect all footings and confirm foundation bolts are at correct centre and level.

2. Install and align main support beams and Trunnion Frames.

3. Pre-assemble and install lower chain case assembly.

4. Place drive chain into the lower chain case. Extend one end approximately 1 meter past the drive sprocket position and extend the other end outside the far end of the chain case. Ensure that the loose ends of the chains are secured in place.

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5. Pre-assemble the two lower sections of the dust housing with the ‘product chute’. Seal all the flanges to prevent ‘egress of dust’. This assembly can then be installed onto the main support beams, fit packing plates under the dust housing support legs at step 9 after installing the barrel at step 7 below.

6. Ensure thrust rollers are clear of the path of the cylinder tyres to allow clearance to install the barrel assembly.

7. Install the pre-assemble barrel and Trunnion bases and position onto Trunnion wheels and between the thrust rollers. Ensure cylinder tyres edges are aligned with the Trunnion tyres edges within 1 mm.

8. Adjust thrust roller to clear cylinder by 1 mm at each end.

9. Shim lower dust housing to ensure uniform clearance around the dust housing and the barrel ‘assembly seal rings’.

10. Pre-assemble the 4 upper section of the dust housing. Seal all flanges to prevent egress of dust.

11. Install the top dust housing assembly to the bottom half of the dust housing. Seal all flanges to prevent egress of dust.

12. Install drive sub-base, align and level as per drawing. Do not grout sub-base to concrete until drive assembly has been installed and sprockets aligned.

13. Install drive-assembly. Ensure correct alignment of drive sprocket and the cylinder sprocket.

Sequence of Operation:

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A. Start-Up: - before starting the Rotary Compressor, follow all procedures as outlined:

1. Start the machine in an unloaded condition.

2. Supply raw material to the feed end of machine only after machine is running at full speed.

B. Shut-Down: -

1. Discontinue feeding the machine.

2. De-energize the breaker, only after all material has been discharged from the cylinder.

• The ‘Fluid Coupling’ applied in 9 * 15 Rotary Breaker is of standard type:

HFN 10/20, HFN 20 and HFDD 20

Trouble Shooting:

Trouble Area Probable Cause Corrective Actions

1.Machine Fails to Start

Electrical Malfunction Check mains is operationalCheck electrical isolations, etc.

2.Motor operating but breaker not

A.Coupling Failure

B.Reducer Failure

C.Bearing Failure

A.Check coupling connectionsB.Refer reducer sectionC.Replace bearing

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D.Cylinder OverloadE.Wedges remain between tyresF.Hydraulic system Failure

D.Remove wedgesE.Inspect/Repair/Hyd. System

3.Bearing hot to touch

A.Inadequate LubricationB.Bearing failure

A.Inspect lubrication flowB.Replace Bearing

4.Cylinder runs hard to one end

A.Trunnion shafts misalignedB.Trunnion base misaligned

A.Align Trunnion shaftsB.Align Trunnion base

5.Vibration/Noisy Operation

A. Trunnion shafts misalignedB.Trunnion base misalignedC.Flat spot on tyres

D.Build up on tyres

A.Align Trunnion shaftsB.Align Trunnion baseC.Replace tyres and re-alignD.Clean tyres faces

• Introduction:

The 9 * 15 Rotary Breaker is to be stored at site prior to erection and during this time it is to be protected from corrosion and generally dust and dirt.

The manufacturers recommend the following storage regime for storage period of upto six months.

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• Corrosion Protection:

The 9 * 15 Rotary Breaker machined surfaces are to be wire brushed clean of surface rust as spray sealed to prevent further corrosion.

The recommended sealent is ‘CRS Soft Steel’. It is petroleum based long term indoor/outdoor corrosion inhibitor that seals out moisture and corrosive contaminants by forming a dry, transparent, amber film which is highly resistant to humidity, salt water and salt spray. The spray which once sets provides a solid film base. The film can easily be removed with petroleum based product.

• Storage:

After application of corrosion protection the 9 * 15 Rotary Breaker is to be stored in a clean dry facility and adequately protected from water (rain, dew, heavy mist etc.) and dust and air born dirt. The storage is to be preferably indoors, however under canvas or an equivalent waterproof cover on a hard stand free of ‘sweating’ is acceptable.

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ALUMINA TRANSFER SYSTEM

• Its other name is HDPS (Hopper Dense Pressure System) and also AAFS (Automatic Alumina Feeding System).

• Alumina Transfer System is the process by which ‘Alumina’ is feeded to the pot with the help of various equipments such as pipe, duct, conveyor and imparting various techniques such as air slides, air lift blower, etc.

• Alumina powder flows in the pipe with the help of ‘Air Slides’. Air slides work on the principle of ‘Potential-Fluidization’. It is of two types:

1. Horizontal air slide.2. Inclined air slide.

• Safe working pressure of Bag House – 4-6.5 kg/cm2.

Safe working pressure of Air Slides – 15-20 millibar (mbar)

• Alumina Produced (Alumina Plant) – 1900MT/Day

• Alumina Transferred to Plant-1 – 400 MT/Day

• Alumina Transferred to Plant-2 – 1500 MT/Day• Conveyors• Air Slides• Air Lifts• Tankers• Elevators

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Plant Starting Sequence:

Long Conveyor – ‘should be in starting condition’ ↓TT – 5 BAG FILTER FAN [2A (6) or 2B (7)]↓TT – 6 AIR LIFT BLOWER [2A (17) or 2B (18)]↓TT – 5 AIR LIFT BLOWER [1A (24) or 1B (25)]↓TT – 5 AIR SLIDE FAN [2A (30) or 2B (31)] ↓

ROTARY AIR LOCK (R.A.L) TT – 5 BAG HOUSE [50, 51, 52, 53]; At the interval of 30 seconds. ↓

BELT CONVEYOR – 2 [32] ↓TT – 2 BAG FILTER FAN [1A (37) or 1B (38)] ↓AIR SLIDE FAN [1A (43) or 1B (44)] ↓

ROTARY AIR LOCK (R.A.L) TT – 2 BAG HOUSE [54, 55, 56, 57]; At the interval of 10 seconds.

↓VIBRATING SCREEN [45], Gate should be placed in side of vibrating screen. ↓BELT CONVEYOR – 1 [47]

• PROCEDURE:

1. Before starting ‘Air Lift Blower’, check that outlet valve of blower is completely open.

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2. Before starting ‘I.D Fan’ check that fan outlet gate is completely open.

3. Before starting the circuit, shut off all R.A.L

4. E very gate and valve of ‘stand by equipment’ should be properly closed.

5. If plant has to be shut down for more than 30 minute, then in that situation TT-5 and TT-2. Bag house pulsing of air should be closed. At the time of restarting of Bag House ‘Rotary Air Lock’ should be start at a minimum interval of 30 seconds.

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FLUORIDE ADSORPTION:

∗ The fresh alumina injected into the reactors serves as an adsorbent for the fluorides and it also helps in creation of a dust layer on the filter bags in order to collect particles even smaller than the fabric mesh itself.

Factor affecting the pressure drop:

1. Gas flow per unit of time and filter area.2. Dust, alumina load and its composition.3. Pulse cleaning frequency.4. Valve operating time.5. Cleaning energy (pulse pressure).6. Gas temperature7. Gas humidity

CLASSIFICATION OF FANS, BLOWERS AND COMPRESSOR:

• Fan is used to develop pressure – Upto 2 psi• Blower is used – From 2 – 10 psi• Compressor is used – Above 10 psi

• Fans:

Throughput of centrifugal or axial fans can be changed by varying the inlet or outlet dampers.

1. Axial fan is used, where air or gas moves parallel to the direction of rotation of axis and to move large quantity of air at low pressure.

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2. Centrifugal fan is used, where air or gas moves perpendicular to the axis and for greater height.

Centrifugal fans:

• Radial blade type• Forward curve type• Backward curve and backward inclined type• Air foil centrifugal fans• Tubular centrifugal fans

Blowers:

∗ Blowers are generally single stage, high-speed machines or multistage units that operate at pressure close to or in the range of compressors.

AIR LIFT BLOWER:

1. Name of Equipment – Air Lift Blower2. Year of Installation – 20003. Manufacturer – KAY INTERNATIONAL LTD.4. Lifting Weight – 25 meter5. Model – AC-10306. Capacity – 100 Metric Tonne7. Type – Twin Lobe Type8. Discharge pressure – 3500 MMWG9. Flow – 7000 M3/Hrs.10. Motor Power – 120 H.P/4 Pole11. Motor Speed/Type – 1440 R.P.M/3 Phase

SPECIFICATION OF FILTER BAGS:

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1. Diameter : I.D – 127 mm2. Length : 6066 mm3. No of bags / line : 32404. Top Design : S.S snap band for bag holding. Top open 5. Longitudinal seam : Triple stitch with polyester thread6. Bottom height : Bottom closed double bottom upto100 mm7. Fabric used : Polyester needle felt8. Composition : 100 % Polyester9. Weight : 550 gm / m210. Thickness : 1.9 mm11. Air permeability : 140 L/dm2/mm at 200 Pa12. Air to cloth ratio : 82 – 85 m3/m2/hr 13. Density of fabric : 0.29 g/ cm314. Gas temperature : 60 to 130°C15. Tensile strength : 1275 N/m16. Bursting strength : 18 Kg/cm2

17. Max dimensional change : < 1% in hot air at 150°C18. Life guarantee : Min 24 months19. Performance : SPM < 8 mg/Nm3;HF <1.5 mg/Nm3

Equipment used for emission measurement: APM 620 supplied by M/S Envirotech, New Delhi

ALUMINA (Al2O3) PROPERTIES

• Bulk density ~ 0.9 - 1.1 g/cm3• Particle density ~ 3.0 - 3.3 g/cm3 • Specific surface ~ 40 - 80 m2/g• Particle size D50 ~ 75 m

~ 10 - 150 m

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DRY SCRUBING SYSTEM

∗ The Dry scrubbing system treats exhaust gas from Pots. This treatment of gases is based on adsorption of gaseous fluoride by means of injected alumina, which is followed by bag filter where enriched alumina is collected and being sent to pots for alumina feeding. This plant can also be named as Fume Treatment Plant.

∗ F.T.P. serves the two functions, first it reduces the emission of the HF gas and the dust particulate into the atmosphere, and secondly it recovers aluminum fluoride, which is an important input to the pots. This reduces the consumption of ALF3, which we purchase from outside party.

NEED FOR D.S.S/F.T.P

∗ During the electrolysis process for producing aluminum, the alumina (Al2O3) liberates oxygen and the metal Aluminum is produced. The electrolysis process takes place in an electrolytic bath consisting of Aluminum fluoride and some other chemicals. During this process hazardous gases are emitted (mainly consisting of Hydrogen fluoride and other fluorides).To prevents these gases to escape into the atmosphere, it is mandatory to install F.T.P. Since fumes are treated by adsorption of fluorides gases into dry alumina, hence the system is called Dry Scrubbing System. The F.T.P. treats exhaust gas from Aluminum reduction cells by dry scrubbing process, followed by bag filter to collect fluorinated (enriched) alumina. F.T.P. reduces the emission of the HF gas and the dust particulate into the atmosphere.

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PROCESS DESCRIPTION

∗ The process description of the F.T.P. is divided into four main sections:

1. Gas Ducting and Fan System 2. Bag Filter System 3. Alumina Handling System 4. Instrumentation and Electrical system

∗ Alumina consumed in the pots is transported from the belt conveyors to the primary silo, through the F.T.P. During This process the primary alumina is mixed with the pot gas in the reactor and forms the enriched alumina. This enriched (secondary) alumina in turn transported to the reduction pots where aluminum metal is produced. Other particulates are collected on the filter bags.

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GAS DUCTING AND FAN SYSTEM:

∗ The main ductwork is designed in such a way that it gives nearly same velocity throughout the system. Each individual pot has the branch duct having a manually adjustable damper. These dampers are set in a fixed position after balancing, so that an even suction is obtained from each pot.

∗ For the suction of the gas there are three main exhaust fans (Centrifugal type) in each line. Each fan has inlet and outlet damper. There are 6-filter unit in each FTP and each filter unit comprises a reactor and a filter compartment.

Each filter unit can be isolated for maint jobs by the inlet duct damper and outlet duct damper.

DUCT CONNECTED WITH POTS:

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AnodeAnode AnodeAnode AnodeAnode

CLEANING OF THE FILTER BAGS

∗ The cleaning of the bags is accomplished by a pulse jet technique, where a medium pressure pulse of air is introduced into the open top of each filter bag through nozzle arranged on a nozzle header. The pulse air enters the nozzle header through solenoid diaphragm valve installed on pulse tanks. There are 30 rows in each bag house and each row comprises of 18 bags. The injection of pulse air results in a rapid expansion of the bags. Alumina and dust having accumulated on the outside of the bags is dislodged and collected in the hopper.

∗ One row in all the filter units is cleaned simultaneously. The next row in line is cleaned after a set time interval has elapsed.

∗ The permeability of a new bag is very high, resulting in a low-

pressure drop. Fumes and alumina in the gas flow will increase the pressure drop through the bags.

BAG CLEANING PARAMETER:

∗ The bag cleaning process is controlled by the PLC installed in control room. All filters are cleaned on-line. This on-line pulsing indicates that one row of bags in each filter unit is cleaned simultaneously. The gas flow, dust load and gas temperature are normally given parameters .The pulse cleaning interval, valve opening time and pulse air pressure for the bags can be varied within limits for optimal operation of FTP.

∗ The pressure drop affects the power consumption of the fans whereas bag-cleaning parameters may affect the life of the bags.

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PULSE SYSTEM:

FILTRATION CYCLE:

BAG HOUSE:

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CLEACLEANN

BAGBAG

DURINGDURINGFILTRATIOFILTRATIO

NN

DURINGDURINGPULSINPULSIN

GG

JUST AFTERJUST AFTERPULSINGPULSING““PUFF”PUFF”

NORMALNORMALFILTRATIOFILTRATIO

NN

ALUMINA HANDLING SYSTEM:

• Alumina transport to primary silo:

∗ The primary alumina is being feed to each FTP from the existing conveyors through a diverter valve leading the alumina into air slides (2 airsides / one standby) for filling of the primary alumina silo (Cap – 350 tons).

An emergency airlift is also provided for filling the primary silo.

PRIMARY ALUMINA HANDLING:

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∗ The primary alumina silo (350 Ton) is equipped with two manually operated discharge valve, one (Bypass) leading directly to the distribution box , the other feeding air slide to a feed box with loss- of –weight control system.

∗ Two blowers are being used to supply fluidizing air to the primary alumina silo and for the feed & distribution system. From the feed box, the primary alumina is being feed into the reactors through distribution air slide where it gets reacts with the pot gases.

ALUMINA INJECTION & RECIRCULATION:

∗ Adsorption of fluorides takes place after the primary alumina has been injected into the raw gas in the reactor. For more enrichment alumina is recirculated from the screw conveyor to the same injection point where the primary alumina has injected.

∗ By varying the speed of the screw conveyor we can control the rate of recirculation. All screw conveyors (6 Nos) rotate with the same speed and is being controlled by frequency converter.

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