Engineering Excellence Awards 2013
Reduction in Energy Consumption
Presented By –
Vedanta Aluminium Limited
Corporate Overview – Vedanta Aluminium Limited, Jharsuguda
Vedanta Aluminium Ltd is an associate company of the London Stock Exchange listed, FTSE 100
diversified resources group Vedanta Resources Plc. originally incorporated in 2001.
The firm operates a 0.5 MTPA Greenfield Aluminium smelter plant 1 and 1215 MW Captive Power Plant
(CPP) supported by highly modern infrastructure at Jharsuguda, Odisha.
In addition to this, construction of 1.2 MTPA Aluminium smelter expansion project at Jharsuguda is
going to be commissioned soon.
Rewards and Recognitions –
IMS Certified Plant (QMS-ISO-9001, EMS-ISO:14001 and OHSAS: 18001)
Frost & Sullivan’s Green Manufacturing Excellence Awards 2013 "Aspirants Award -Large Business"
Received certification for ISO: 50001, Energy Management System.
Best HR strategy in line with Business by World HRD congress.
Received certification for ISO: 27001 in information Security,
Recognized as “Excellent Energy Efficient Unit” at 14th National Award for “Excellence in Energy Management
2013” organized by CII.
Third prize in “All Odisha EHS Award 2013” by CII.
Vedanta Aluminium Limited, Jharsuguda
“We will be the world’s most admired
company that consistently defines the
leading standards in our businesses,
making our stakeholders proud to be
associated with us.”
“Our mission is to be a world-class
metals and mining group and generate
superior financial returns.”
Fundamentals Of Hall Heroult Process
The amount of substances
deposited or dissolved during an
electrolytic process is proportional
to the quantity of electricity passed
through the electrolytic cell.
96485 Coulombs deposit – 1 gm Equivalent of Aluminium
One gram equivalent weight of
matter is deposited or dissolved on
each electrode for 96485 Coulomb
(Faraday Constant ) of electricity
charge passed through the
1 KA in 24 Hrs produces – 8.052 Kg of Aluminium
Raw material Consumption – Production of Aluminium
To produce 1 T of aluminium the following
amounts of raw materials are needed:
4 T bauxite
Aluminium fluoride +
+ CO + HF + CF4 + Coke +
13000 - 15000 kWh
Constituents of Pot Voltage
Transition Joint Drop
Steel Yoke Drop
Stub to Carbon Drop
Anode block Drop
Cathode block drop
Introduction to Bath Voltage & its components
The bath voltage contains a resistance & an electrochemical
Components of Bath Voltage
•E0 – Reversible Electromotive
•U Ω – Ohmic Bath Voltage
•UBub – Bubble Voltage
•Anodic Reaction Overvoltage
Reasons for High Voltage drop across the Electrolyte
During Aluminium smelting, CO2 gases are
CO2 bubbles get accumulated under the
anode – forms a high resistance partially
Gas accumulation under the anode
How to reduce the bubble Drop???
Minimizing bubble drop - most economical way to reduce
Modification of anode surface by Introducing slots can
reduce both the bubble drop and anode overvoltage.
Scope of reduction – 50-100 mV
Conceptualization & Design Engineering
Anode surface slots were not present in
the initial design.
In house design engineering done
for appropriate slot height and
Straight slots may be a problem in gas
Design of experiment and data
analysis performed on Slanted
Design modifications have been made in
the anode forming equipment (Vibrocompactor).
Ensure proper removal of packing coke.
Clogging of the slots will lead to excess
coke dusting in pots.
In situ Design & Installation of Slot
cleaning machine in bake oven.
Slotted Anode Trial (Line 1-Section 7)
period – 27th July to 25th Oct
Sample Population – 6.3% of the total operating pots.
Total no. of anodes made for Trial – 5000 nos.
• Reduction in Pot Voltage - reduction of 16 mV
• Reduction in AEF - Reduction of 0.28 no./pot day.
• Reduction in Noise - Reduction of 1.01 mV.
• Net saving in Power Consumption of 51.2 kWh/MT.
24-Aug to 2028-jun to 26-Jul 27-jul to 23-Aug
21-sep to 18Oct
Pot room Parameter Analysis for Slotted Anodes on Full line
Implementation period – 23rd Oct’12 to 13th Jan’13
Reduction in Pot Voltage - a net reduction of 21 mV.
•Net saving in Power Consumption of 67.3 kWh/MT. (36.44 MU/Year)
Increase in productivity –
•Current efficiency increase by 1.32%. Volume increase by 20.89 Kg/Day
•Amperage Ramp – Net increase of 1.89 KA. Production Volume Increase by 8.6 Kg/Day
Reduction in AEF - 0.15 no./pot day. Total reduction by 46%
•Reduction in PFC & CO2 Emissions – Net reduction by 57% in whole pot line.
Trial & Full Implementation - Impact on Energy consumption
Full Implementation of Slotted Anodes
Impact on CE
In practice, an electrolytic pot always produces less Aluminium than is as per theoretical (Faraday’s
Actual CE % = (Actual Production/Theoretical Production)*100
Slotted Anodes and Environment – Impact on AEF and PFC Emissions
Full Implementation of Slotted Anodes
Impact on AE
Impact on PFC
CF4* and C2F6*
(MT/MT of Al)
*CF4 (MT/MT) – AEF*AED*0.14, C2F6 (MT/MT) - AEF*AED*0.14/10 (As per universally accepted calculation)
Intangible Gains through Slotted Anodes
Impact of Slotted anodes
Conservation of non renewable
resources of energy.(Coal & Oil)
Total Power Savings by 36.44
Reduction of CO2 emissions by –
Emissions of green house gases (PFC) reduced by 57%.
Manpower productivity has improved.
Anode effect frequency has been
decreased to a large extent productivity has increased.
Elimination of Safety and health hazard
reduced anode effect frequency
and immediate auto quenching
Way forward -
Reduction of energy by additional
60 Kwh/MT of Al
Calculations for CO2 Emissions
Savings by Slotted anodes = 67.3
Considering 93.6% CE, 6
3 pots, 326.5 KA.
Savings in a yr. =
Now, 1Mwh = 1000 Units
Now, 1 MU = 1 Gwh
As of world standards, The level of the performance standard will be fixed at 420 tonnes
of carbon dioxide per gigawatt hour (CO2/GWh).
therefore, by implementing Slotted anodes, savings in CO2 Emissions /Yr. will be