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Energy Usage in South African

Permanent Mould (Die Casting)

Foundries

Carl ReinhardtKJJC Trading cc Trading as

Casting Services

November 2009

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Disclaimer

• Casting Services has relied substantially upon information provided by the literature and by experts in the field. Casting Services has not made any assessment of the technology and no such assessment is implied by the statements made in this report.

• The other information contained in this course has been compliedfrom information from NADCA, NFTN, contained within Casting Services’ and associates files and database and from local companies and published industry information.

• Every effort has been made to ensure that the information presented and the conclusions reached are realistic and not misleading. However Casting Services makes no warranty as to the accuracy ofthe information contained within this course and will accept no responsibility or liability for any loss incurred by any person or organisation relying on the information in this report

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Energy Costs Money

• Don’t waste it• Insulation

• Unburnt fuel

• Dross build up

• Wasted heat – often easily “captured” use to

preheat

• Dross and metal loss

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Energy Cost Money

– Use it well

• Yield

– Casting Yield

– Machining Yield

• Rejects

• Metal Losses

• Don’t overheat your metal

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Energy Costs Money

– Use the most cost effective

• For your area

• For your furnace type

• For your metal type

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South African Foundries

• Data

– How much Energy Do we Use?

– Data

– How much does it cost?

– Data

– How much do the different energy types cost?

– Data

7

The DataThe Data must be

relevant

The Data must be

up to date

The Data must be

comparable

The Data must be

meaningful

The Data must be

clearly defined

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South African Foundries

• Permanent Mould Foundries

– Die casting

• Gravity

– Conventional

– Tilt

– Counter Gravity/pseudo low pressure (tilt with furnace

attached)

• Low Pressure

• High Pressure

– Spin Casting

• Vertical

• Horizontal

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Gravity Die Casting

High Pressure Die Casting (Cold Chamber)

Counter Gravity

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South African Foundries• Other types of foundries

– Anything that isn’t a permanent mould foundry

– This data is collected from permanent mould

foundries

– Although there are a number similarities

• Furnaces

• Yields, metal losses, thermal + fuel losses etc

• But the data is specific to and collected from Permanent mould foundries (although a small

number of the foundries also had a sand

department)

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The Data

• Data Collected from site visits to foundries between July 2009 to September 2009

• Data from 38 Permanent mould Foundries

• Data from another 8 Permanent mould foundries collected in September 2008 (pilot project)

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Types of Foundries

Data Collected from

• 13 (+8 from Sept 2008) foundries who engage in

• High Pressure Die Casting Hot and or Cold Chamber

• Some of them also do Gravity (one did a little sand)

• Some also Low Pressure

• All non-ferrous– Aluminium and/or

– Brass and/or

– Zinc

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Types of Foundries

Data Collected from

• Another 15 Foundries who do

– Gravity Casting

– Tilt (and Counter Gravity)

– Some also did Low pressure casting

– All ran

• Aluminium

• Some ran a bit of Zinc as well

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Types of Foundries

Data Collected from• A further 9 foundries

– Who do • Gravity die casting• Low Pressure die casting• Some also do Sand casting

• And a conti-caster making bearings

• All non-ferrous– Aluminium and/or– Zinc and/or

– Brass

– One Foundry does Aluminium Gravity and Sand casting and sand casting bronze (Gun metal)

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The Data

• Total GJ (Energy usage of all 38 foundries over 12 month period)

– 447 453 GJ

– This is enough to theoretically melt and superheat 372 878 tons

- These foundries only Melted 15 792tons

• Total Rand paid for this energy (includes kWh, kVA Service charges, Gas etc)

– R 51 707 272 (R115/GJ)

• Average Cost of Energy as a percentage of sales

– 5.46% of Turnover spent on Energy

• Could we save any Energy ? YES

• But holding Costs are not in here

• One foundry has reported a 20% saving in energy usage due to insulation and lids.

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The DataTotal Energy Consumption

GJ/tonne sold

0 20 40 60 80 100 120 140 160

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Energy CostEnerg y cost s as % C ast ing Sales

0.00% 5.00% 10.00% 15.00% 20.00% 25.00%

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The DataYield

Gravity

0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00%

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Yield

Hot Chamber

0.00% 20.00% 40.00% 60.00% 80.00% 100.00%

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The DataYield

Low Pressure

50.00% 55.00% 60.00% 65.00% 70.00% 75.00%

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Yield

Cold Chamber

0.00% 20.00% 40.00% 60.00% 80.00% 100.00%

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DrossA l D ro ss Percent age

0.00% 5.00% 10.00% 15.00%

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pany

Zn D ross Percent age

0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00%

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pany

B rass D ross Percent age

0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00%

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The Data• Reject Rate

– Over half of the companies did not record their rejects formally.

– Three quarters of them did not record rejects at

casting (thrown back in the “pot”)

– They don’t know how much energy (let alone other

costs) they are wasting due to rejects

– The Reject rates reported (although inaccurate as a

result of above comments)

• Gravity - median 8%

• Hot Chamber – median 7.5%

• Cold Chamber – median 12%

• Low pressure – median 15%

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Types of Foundries

Data Collected from

Are you still with me?

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Calculations to GJ

Approximate Calculation factors*

• Electricity – kWh to GJ – kWh x 3600/1000/1000

• Natural Gas – Normally given in GJ (in SA)

• Paraffin – Litres to GJ – Litres x 0.8 x 43.3 /1000

• Coke – kg to GJ – kg x 27 / 1000

• Diesel – Litres to GJ – Litres x 0.85 x 43 / 1000

• LPG – kg to GJ – kg x 46.3 /1000 (density 0.5)

• Other (Heavy oils etc), litres to GJ ≈ Litres x 0.93 x 41.7 / 1000

* Actual values are specific to the fuel suppliers manufacture techniques and other

factors

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The Costs of Energy in SA

5.053.341.64R/l19512963Oil - HFO to Used Oil

8.136.204.46R/kg376287206LPG

7.405.372.68R/l27019698Diesel

8.238.238.23R/kg222222222Coke

5.555.064.58R/l192175158Parafin

196.36158.37123.15R/GJ196158123Natural Gas

0.99080.84570.2545R/kWh27523470Electricity

90th percentileMedian10th percentile90th percentileAverage10th percentile

R/GJ

Average Unit Cost of Different Energy Types in South Africa [R/GJ]

0 50 100 150 200 250 300 350 400

Electricity [kWh]

Natural Gas

Parafin(litres)

Coke(kg)

Diesel(litres)

LPG [kg]

Oil - HFO to Used Oil

R/GJ

90th Percentile

Median

10th Percentile

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Real Cost• According to Energy Workshop in USA August 2009

• Efficiency of Furnaces

• Furnace types for different Fuels– Electricity –

• Resistance – Indirect (ŋ=50%-80%)Direct (Even higher)

• Induction – Coreless / Channel (ŋ=59%-76%)

– Paraffin,Diesel, LPG, Oil, …..

• Reverbatory – Radiant Roof (ŋ=10%-35%)Stack (ŋ=40%-45%) Crucible (ŋ=7%-19%)

– Coke (Coal)

• Crucible (pit furnace) (ŋ≈5%-12%)

• Cupola (ŋ =40%-50%)

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Real Cost to Heat Metal

• Real Cost – Cost to put energy into metal R/Metal GJ

– Depends on Furnace type – the furnaces

efficiency

– Depends on Energy Cost per Unit

– R / metal GJ = Energy Cost per Unit /ŋfurnace

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Real Energy Cost to Heat Metal wrt Furnace type

R 1,852R 4,44412%5%Pit furnace

R 444R 55650%40%CupolaCoke

R 683R 1,85419%7%Crucible

R 288R 32445%40%Stack

R 371R 1,29835%10%Reverbatory (Radiant Roof)Oil HFO/Recycled

R 1,511R 4,10219%7%Crucible

R 638R 71845%40%Stack

R 820R 2,87135%10%Reverbatory (Radiant Roof)LPG

R 1,035R 2,80919%7%Crucible

R 437R 49245%40%Stack

R 562R 1,96635%10%Reverbatory (Radiant Roof)Diesel

R 924R 2,50819%7%Crucible

R 390R 43945%40%Stack

R 502R 1,75635%10%Reverbatory (Radiant Roof)Paraffin

R 834R 2,26219%7%Crucible

R 352R 39645%40%Stack

R 452R 1,58435%10%Reverbatory (Radiant Roof)Natural Gas

R 309R 39876%59%Induction

R 294R 47080%50%ResistanceElectric

LowHigh HighLowFurnace TypeEnergy Source

R/Metal GJEfficiency

Electricity Costs for 2008 – Plus 25% for 2009

Plus?? For 2010,11,12

Electricity, Plus 25%- R587 to R367

- R498 to R386

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Real Energy Cost to Heat Metal wrt Furnace type

470

398

1,584

396

2,262

1,756

439

2,508

1,966

492

2,809

2,871

718

4,102

1,298

324

1,854

556

4,444

294

309

452

352

834

502

390

924

562

437

1,035

820

638

1,511

371

288

683

444

1,852

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000

Electric Resistance

Electric Induction

Natural Gas Reverbatory (Radiant Roof)

Natural Gas Stack

Natural Gas Crucible

Paraffin Reverbatory (Radiant Roof)

Paraffin Stack

Parafinn Crucible

Diesel Reverbatory (Radiant Roof)

Diesel Stack

Diesel Crucible

LPG Reverbatory (Radiant Roof)

LPG Stack

LPG Crucible

Oil Reverbatory (Radiant Roof)

Oil Stack

Oil Crucible

Coke Cupola

Coke Pit furnace

R / Metal GJ

High Cost (low efficiency) Low Cost (High Efficiency)

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Conclusion

• Use best energy for your area

– Find out how much different energy types cost

in your area

• Use and setup your furnaces efficiently

• Use and setup your production systems efficiently