practical applications of improving energy efficiency in foundries

1. BRICS FOUNDRY FORUM 2012
HOSTED BY
CHINA FOUNDRY ASSOCIATION
PRACTICAL APPLICATION OF IMPROVING
ENERGY EFFICIENCY IN FOUNDRIES
PRESENTED BY:
John T Davies
CEO – South African Institute of Foundrymen

2. THE SOUTH AFRICAN FOUNDRY INDUSTRY
1. NUMBER OF FOUNDRIES
METAL TYPE 2003 2007 2011 %Change
2011/2007
Ferrous 110 110 101* 8
Non Ferrous 103 101 80 21
TOTAL 213 211 181 14
* Includes 4 Investment Casting Foundries
In addition there are 13 Art Foundries and 9 Spin Casters
cf Germany = 900
USA = 2000
China = 2600

3. DEFINITION
• “Demand Side” refers to the demand for, or consumption of,
electricity.
• “Demand Side Management” refers to interventions to reduce
energy consumption
• “Energy Efficiency” refers to the effective use of energy to produce a
given output (in a production environment)
• technology is one that which produces the same service or output with
less energy input.
• “Green Technology” means
• Technology that when properly implemented allows an organisation to
meet its present needs without compromising its future needs.

4. The Case for Energy Efficiency
South Africa vs. the Rest of the World
Per Capita Electricity Consumption for Countries with similar GDP per capita (± 20%) relative to South Africa*
1.20
Gabon
1.15 (1,128 kWh pa)
GDP per capita x South Africa GDP per capita
1.10
Venezuela (Bolivarian Republic of)
1.05 (3,770 kWh pa) Russian Federation
(6,425 kWh pa)
South Africa
Mauritius Turkey Malaysia
1.00 (4,818 kWh pa)
(1,775 kWh pa) (2,122 kWh pa) (3,196 kWh pa)
Saint Lucia Uruguay
0.95
(1,879 kWh pa) (2,408 kWh pa) Compared to other
Panama
(1,807 kWh pa) Argentina countries with a similar per
(2,714 kWh pa)
0.90
Costa Rica capita GDP (15% variance),
(1,876 kWh pa) Romania
(2,548 kWh pa) SA is more electricity
Grenada
0.85
(1,963 kWh pa) intensive by factor of 35-
Brazil
(2,340 kWh pa)
65%
0.80
- 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Electricity consumption per capita x South Africa Electricity consumption per capita
Source: UN (United Nations). 2007d. The 2004 Energy Statistics Yearbook. Department of Economic and Social Affairs, Statistics Division. New York.
44
*Situation as in 2004, beneficiation policy and co-generation will alter the above picture

5. Together we have the power to save 5

6. Benchmarks
Programmes Offer
Lighting & HVAC Up to 5.2m/MW
Solar water heating (SWH) Up to 6.3m/MW
Heat pumps Up to 5.2m/MW
Demand Response Up to 3.5m/MW
Compressed Air Up to 4.4m/MW
Process Optimisation Up to 5.2m/MW
Shower Heads Up to 2.8m/MW
Together we have the power to save 6

7. ESCO Implementation Model
Eskom DSM
• Evaluation DSM Customer
• Financier Agreement • Sustainability
ESCo
ESCo Maintenance or
New Engineering
Contract • Audit Performance
• Proposal agreement
• Installation
Together we have the power to save 7

8. Mold Making Heat Treatment
12% 6%
Other
12%
Core Making
8%
Melting
55%
Post Casting
7%

9. ENERGY SAVING OPPORTUNITIES
1. SCRAP SELECTION AND PREPARATION
2. CHARGING
3. MELTING
4. ALLOYING / REFINING / TREATMENT / SAMPLING
5. HOLDING
6. TAPPING / LADLES
7. TRANSPORTING METAL
8. POURING
9. MAINTENANCE OF PLANT AND EQUIPMENT

10. 1. SCRAP SELECTION AND PREPARATION
• Safety
• Correct Size
• Density
• Cleanliness:
 Sheared versus shredded scrap
 Rusted scrap
 Briquetted swarf
• Preheating of scrap?
• Induction melting Limits the range of scrap used

14. 2. CHARGING OF SCRAP
• Prepare the Charge Sequence
• Vibrating Systems
• Continuous Charging During the Melt
• Pre Heat the Charge in the Furnace
• Focus on Reducing the Duration of Charging to Maximise the Melting Process

15. 3. MELTING THE CHARGE
• Mains versus medium Frequency / cupola
• Theoretical Power Versus “Best Practice”
• Benefits of Batch Melting
• Efficiency (No Holding) 97 Percent
• Max Power
• Power Density
• Melting Rate
• Furnace Size
• Production Planning
• Less Emmision
• Improved Control
• Improved Homogeneity
• Furnace Lids / Covers
• Slag and Dross

16. Comparison of Practical Minimum, Theoretical Minimum and Best Practice Minimums for
Selected Processes
Best Tactic Best
Theoretical Industry % Practice % Practice
Selected Processes Minimum Average Difference Minimum Difference Minimum
Iron Induction Melting 351.5 796.3 56% 538.1 35% 1,689.50
Iron Cupola Melting 351.5 1,413.60 75% 1,002.50 65% 1,124.50
Aluminum Reverberatory 288.7 1,399.80 79% 510.5 43% 523.2
Melt Furnaces
Estimated Iron Induction Melting Energy Usage
Per Ton Melt
Gross Melt Tacit Tacit Tacit
10 Btu /
Item KWh/Ton Loss KWh/Ton KWh/Ton 10 Btu / Ton 10 Btu / Ton Ton**
Heel Melting Calculated 800 1.5% 812 2550 2.77 8.71 14.52
Heel Melting and Holding Estimated 954 1.5% 969 3041 3.31 10.39 17.31
Modern Batch Melter Caclulated 500 1.5% 508 1594 1.73 5.44 9.07
Batch Melter and Holding Estimated 530 1.5% 538% 1690 1.84 5.77 9.62
Includes Hold Power for 8 Hours per day and preheat gas at 74 kWh/ton melt for heel melter
Ship tons consider 60% yuekd

17. Induction and Cupola Melting Energy Comparison 10' Btu / Ton
Melt Tacit Melt Tacit Ship
Item Energy Energy Energy
Induction Heel Melting 3.31 10.39 17.31
Modern Induction Batch Melting 1.84 5.77 9.62
Low Efficiency Cupola 4.92 5.76 9.6
High Efficiency Cupola 3.25 3.84 6%

19. Historical Induction Melting Furnace Energy* (Delivered)
900
800
700
600
500
400
kWh/ton
300
200
100
0
1950 - 1960's 1960 - 1970's 1970 - 1980's 1990's

20. 4. ALLOYING / REFINING / DE - SLAGGING / SAMPLING
• Ferro – Alloy Additions
• Sampling – Floor Controls
• Sampling – Spectrometer Analysis
• Slag Removal – Tools, Efficiency
• Slag Wall, Slag Build – Up – Use of Fluxes
• Treatment of Metal

21. 5. HOLDING
• Avoid Holding Metal in Batch Furnaces
• Melt Cold – Pour Hot

22. 6. TAPPING / LADLES
• Refractories
• Pre Heating Using Oxy – Fuel to Improve Efficiency
• Management

23. 7. TRANSFER OF MOLTEN IRON
• Preparation
• Speed and Accuracy of the Operation
• Temperature Control
• Skimming

24. 8. POURING
• High Power Thermal Plasma Heating
 Efficient Heating
 Fast
 Offers Metallurgical Benefits
• Existing Systems = Ladles & Auto Pouring Units
Both have Disadvantages
• HPTP Offers a Cost Effective Solution
• Improved Temperature Control to +- 5 C
• Energy Efficiency Improvement of 20%

25. 9. MAINTENANCE
• Refractories:
 Replacement Schedule – Push Out
 Type of Refractory
 Campaign Life
 On Going Repairs – Chemical Erosion Leading to Failure
 Measurement
• Furnace:
 Regular Coil Inspection
 Water System Quality
 Control of Harmonics
 Short Main Power Cable Supply

26. CONCLUSION
• There is no “One Size Fits All” Solution
• There are no immediate technological innovation in the melting of Iron
(No Magic Wand)
• Retrofitting Technology is Available for many frequency Furnaces
• The Approach Recommended is Continuous Improvement in Small Increments
• Opportunities for Energy Savings EXIST

27. ACKNOWLEDGEMENTS
• Advanced Melting Technologies “BCS Inc Nov 2005”
• Theoretical / Best Practice Energy Use in Metal Casting Operations “JF Suhfo, JT Radia – May 2004”
• Improvement in Energy Efficiency of a Melting furnace “Dr DS Padan, Tata Motors Limited”
• High Power thermal Plasma Heating in Automotive Casting Units: Tomorrow’s Technology Applied to
Today’s Casting “Luis Cobos Enal 2010”
• Casting Directory 2011 “Crawford Publications”
• How to become a practical Green Foundry Indsustry?
“G Gigante, Thyssen Krupp – Wupaca, WI USA 2010
• ESKOM – Discussion with the Foundry Industry – Stephen Koopman, Energy Manager RSA 2010