practical applications of improving energy efficiency in foundries

BRICS FOUNDRY FORUM 2012HOSTED BY

CHINA FOUNDRY ASSOCIATIONPRACTICAL APPLICATION OF IMPROVING

ENERGY EFFICIENCY IN FOUNDRIESPRESENTED BY:John T Davies

CEO – South African Institute of Foundrymen

THE SOUTH AFRICAN FOUNDRY INDUSTRY

1. NUMBER OF FOUNDRIES

* Includes 4 Investment Casting Foundries

In addition there are 13 Art Foundries and 9 Spin Casters

cf Germany = 900USA = 2000China = 2600

METAL TYPE 2003 2007 2011 %Change 2011/2007

Ferrous 110 110 101* 8

Non Ferrous 103 101 80 21

TOTAL 213 211 181 14

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 4

Per Capita Electricity Consumption for Countries with similar GDP per capita (± 20%) relative to South Africa*

The Case for Energy EfficiencySouth Africa vs. the Rest of the World

Gabon(1,128 kWh pa)

Russian Federation(6,425 kWh pa)

Venezuela (Bolivarian Republic of)(3,770 kWh pa)

Malaysia(3,196 kWh pa)

South Africa

(4,818 kWh pa)Mauritius

(1,775 kWh pa)Turkey

(2,122 kWh pa)

Saint Lucia(1,879 kWh pa)

Uruguay(2,408 kWh pa)

Panama(1,807 kWh pa) Argentina

(2,714 kWh pa)Costa Rica

(1,876 kWh pa) Romania(2,548 kWh pa)

Grenada(1,963 kWh pa)

Brazil(2,340 kWh pa)

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

- 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

GD

P p

er c

apit

a x

So

uth

Afr

ica

GD

P p

er c

apit

a

Source: UN (United Nations). 2007d. The 2004 Energy Statistics Yearbook. Department of Economic and Social Affairs, Statistics Division. New York.

Compared to other countries with a similar per capita GDP (15% variance),

SA is more electricity intensive by factor of 35-

65%

*Situation as in 2004, beneficiation policy and co-generation will alter the above picture

Together we have the power to save 5

Together we have the power to save 6

BenchmarksProgrammes 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 7

ESCO Implementation Model

DSMAgreement

Maintenance orPerformance agreement

New EngineeringContract

ESCo• Audit

• Proposal• Installation

Eskom DSM• Evaluation• Financier

Customer• Sustainability

ESCo

Heat Treatment6%

Melting55%

Post Casting7%

Core Mak-ing8%

Other12%

Mold Making12%

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

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

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

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

Best Tactic BestTheoretical Industry % Practice % Practice

Selected Processes Minimum Average Difference Minimum Difference MinimumIron 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% 523.2Melt Furnaces

Comparison of Practical Minimum, Theoretical Minimum and Best Practice Minimums for Selected Processes

Estimated Iron Induction Melting Energy Usage

Per Ton MeltGross Melt Tacit Tacit Tacit

Item KWh/Ton Loss KWh/Ton KWh/Ton 10 Btu / Ton 10 Btu / Ton 10 Btu / 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 9.62Includes Hold Power for 8 Hours per day and preheat gas at 74 kWh/ton melt for heel melterShip tons consider 60% yuekd

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%

1950 - 1960's 1960 - 1970's 1970 - 1980's 1990's0%

10%

20%

30%

40%

50%

60%

70%

80%

Energy EfficiencyTacit Energy Efficiency

Iron Induction Melting Energy Efficiency

1950 - 1960's 1960 - 1970's 1970 - 1980's 1990's0

100

200

300

400

500

600

700

800

900

kWh/ton

Historical Induction Melting Furnace Energy* (Delivered)

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

5. HOLDING

• Avoid Holding Metal in Batch Furnaces

• Melt Cold – Pour Hot

6. TAPPING / LADLES

• Refractories

• Pre Heating Using Oxy – Fuel to Improve Efficiency

• Management

7. TRANSFER OF MOLTEN IRON

• Preparation

• Speed and Accuracy of the Operation

• Temperature Control

• Skimming

8. POURING

• High Power Thermal Plasma Heating Efficient Heating Fast Offers Metallurgical Benefits

• Existing Systems = Ladles & Auto Pouring UnitsBoth have Disadvantages

• HPTP Offers a Cost Effective Solution

• Improved Temperature Control to +- 5 C

• Energy Efficiency Improvement of 20%

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

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

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