Team Hindalco

Welcomes You All

Hindalco Industries Limited, Renukoot

Team Introduction

2

Vibhav Upadhyay

Anuj Verma

Vivek Agrawal

Aspect of Energy Saving

Ensuring Energy Security.

Climate Change Concerns.

Statutory requirement like PAT , RPO

etc.

Methodology

By Enhancing Energy Efficiency.

By Energy Conservation Hindalco Industries Limited,

Renukoot

3

To Reduce Pot Voltage at Renukut

Smelter to Enhance Energy Efficiency

16 Nov 2016 4

Project Theme

INDEX

Hindalco Renukoot – Profile & Process introduction

Background of the Project

Concept of the Project

Root cause Analysis and Approach adopted

Project Savings & Economics

Challenges faced in implementation

Measurement and Verification

Hindalco Industries Limited,

Renukoot

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Hindalco, the flagship company of the

Aditya Birla Group and industry leader in

aluminium and copper has consolidated

turnover of US$17 billion & having

footprint in 13 countries outside India.

It is fully integrated plant.

Hindalco Renukoot: Profile

Hindalco Industries Limited,

Renukoot

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Finish Product

Aluminium

Hindalco Renukoot : Fully Integrated Operations

Alumina Bauxite

Captive Power

TH

RO

UG

H

7

Typical Cost of Aluminium Production

Smelter Power 40%

Store, potlini ng, misc.

4%

AlF3 1%

Depriciation 1%

Net carbon 15%

Alumina 35%

wages 5%

8

Renukut Smelter

•Renukut smelter has 11 pot lines and 2138 Electrolytic cells

(pots). Annual Aluminum Production is 409 KT.

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Process Description ALUMINA HOPPER

ANODE (+)

ANODE (+)

MOLTEN CRYOLITE BATH MOLTEN ALUMINIUM

CATHODE BLOCK (-)

POINT FEEDERS

SiC BRICKS

DIATHERM 23

INSULATION

BRICKS

CATHODE BUS BAR

COLLECTOR

BAR

POT COVERS

ALUMINA

INSULATION

FROZEN BATH

CRUST

TOE PLATE

MONOLITHIC PASTE

LINING

DENSE FIRE

BRICKS

2 AI2O3 + 3 C 4 AI + 3 CO2

ANODE RING BUS

CALCIUM

SILICATE

INSULATION

MOLTEN METAL

According to Faraday’s Law:

Production = 8.052* Amperage*Current Efficiency 10

Project background

•Power Consumption

298/ CE

VkgkWh

4.420

4.440

4.460

4.480

4.500

4.520

4.540 Pot voltage, V

This project was taken to reduce pot voltage by 80 mv

11

Problem Diagnosis

12

Project Scoping

13

Approach

14

Project Methodology:

Statistical analysis of process parameter

Stability Test ( Run Chart)

Process Capability

Gage R & R Study

Micro mapping & Process Mapping

Regression Analysis

Cause and effect analysis

Macro Map

Pot Lining

-New pot shell

-Refractory lining

Pot baking

-Pot taken

in circuit

Pot Loading

-Pot taken in

operation

Alumina Feeding

-Installation of point

feeders and Micro

Processor control

Metal Tapping

-Metal tap out in

cruce

Crust breaking

-Crust breaking

- Bath melting

Bath maintenance

- Solid bath addition

Anode changing

-Spent anode removal

Dust skimming

-New anode set

- Anode covering

Sampling

-Bath ratio, temperature

- Bath Level

measurement

•DC Power from Rectifier

•Anodes from carbon

plant

-Corrections

-Bath ratio balance

by adding AlF3 or

Soda ash

- Bath maintenance

•Primary alumina from Alumina

plant

•Secondary alumina through DSS

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Fish Bone Diagram

Team did round of brainstorming sessions to identify all

potential causes using fishbone diagram. Total 18 X’s

identified which further reduced to 10 using C&I matrix 16

17

ACD

Cathode Voltage drop

Pot age

Noise

Alumina concentration

Metal level

Anode effect

Bath Chemistry

Clamp drop

Diamond drop

Critical parameters

Regression Analysis

Correlation & regression analysis carried out to find out

most critical parameters 18

Regression Analysis

•Series of DOE were carried out to find out the way to reach

at optimum pot voltage without affecting other critical

parameters.

•A Solution Selection Matrix prepared to prioritize the

solution and different DOE (Design of Experiments)

conducted. Finally an action plan made to reduce pot voltage.

.

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Pot age ,ACD ,Noise ,CVD, Bath Chemistry

Problem Remedy

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Voltage Reduction Plan

Problem Remedy

Noise

1. Noise limit for voltage reduction –Avg. noise value 0.002V/pot

2. Voltage will be reduced @ 0.01V/pot only

Age

1. Minimum voltage of 4.27 V with life 90 to <3000days.

2. High life (>3000 days) voltage 4.36 V(min)

3. New pot maintained upto 4.320 V/pot by 90 days of life.

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Problem Remedy

CVD

1. Voltage of pots with high CVD is 4.35 (min)

Bath Chemistry

1. Bath Ratio target increased from 1.130 to 1.160 due to higher

CaF2 content in bath

2. Maximum 0.06 V reduction in one week

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ACD

1. No voltage reduction if pot is under high noise, low bath level,

metal left in the pot, and less current anodes

Control Plan

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Monitoring parameters

• Metal Left

• High bath temperature Pots.

• High Bath Ratio Pots.

• Low Bath Level Pots.

• Anode Effect frequency.

• High search time ( higher Alumina content in bath) pots.

• Avg. Noise of the lines and No. of noisy pots.

• No. of pot failure

Monitoring of all these parameters and strategy change in between

whenever deviations found.

Control plan for Improvement

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• Formation of Standard Operating Practices.

• Extended trial in all pot lines before implementation

• Implemented in all pot lines

• An exhaustive monitoring system developed

•Any deviations were planned to be rectified within 8 hrs

Replication

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Results

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Tangible Results

July'15 Aug'15 Sep'15 Oct'15 Nov'15 Dec'15 Jan'201

6 Feb'16 Mar'16

Pot voltage 4.515 4.513 4.479 4.470 4.453 4.448 4.450 4.444 4.442

Volts/p

ot

Pot voltage

Strict follow up of action plan led to reduction in pot voltage 27

Tangible Results

4.400

4.420

4.440

4.460

4.480

4.500

4.520

4.540

July

'15

Aug'1

5

Sep'1

5

Oct'1

5

Nov'1

5

Dec'1

5

Jan

'20

16

Feb'1

6

Mar'16

Volts/p

ot

Pot voltage

• Improvement in CTQ

28

Tangible Results

13800

13850

13900

13950

14000

14050

14100

14150

14200

14250

14300

Ju

ly'1

5

Au

g'1

5

Se

p'1

5

Oct'15

No

v'1

5

De

c'1

5

Ja

n'2

01

6

Fe

b'1

6

Ma

r'1

6

Power, kWh/T

•Improvement in Power consumption

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Tangible Results

30

Power consumption reduced by

284 kWh/ T

• Enhance in process consistency also improved

metal purity

• Lowest Iron content and Silicon content in

aluminium.

• Increased Internal customer satisfaction

Intangible Results

31

Thank You

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