Energy Usage in South African Permanent Mould (Die Casting) Foundries

1. Energy Usage in South African
Permanent Mould (Die Casting)
Foundries
Carl Reinhardt
KJJC Trading cc Trading as
Casting Services
November 2009
1

2. 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 complied
from 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 of
the 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
2

3. 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
3

4. Energy Cost Money
– Use it well
• Yield
– Casting Yield
– Machining Yield
• Rejects
• Metal Losses
• Don’t overheat your metal
4

5. Energy Costs Money
– Use the most cost effective
• For your area
• For your furnace type
• For your metal type
5

6. 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
6

7. The Data The Data must be
relevant
The Data must be
comparable
The Data must be The Data must be
clearly defined up to date
The Data must be
meaningful
7

8. 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
8

9. Gravity Die Casting
High Pressure Die Casting (Cold Chamber)
Counter Gravity
9

10. 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)
10

11. 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)
11

12. 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
12

13. 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
13

14. 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)
14

15. 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.
15

16. The Data
Total Energy Consum ption
Energy Cost
Energ y GJ/tonne C ast i ng Sal es
co st s as % sold
90t 90th
h
M edian
M edian
10t h10th
38 38
37 37
36 36
35 35
34 34
33 33
32 32
31 31
30 30
29 29
28 28
27 27
26 26
25 25
24 24
Company
Company
23 23
22 22
21 21
20 20
19
19
18 18
17
17
16
16
15
15 14
14
13
13 12
12 11
11 10
10
9
9 8
8 7
7 6
6 5
5 4
4 3
3 2
2 1
1
0.00% 5.00% 10.00% 15.00% 20.00% 25.00%
0 20 40 60 80 100 120 140 160
16

17. The Data
Yield Yield
Hot Cham ber Gravity
90th 90th
M edian M edian
10th 10th
38 38
37 37
36 36
35 35
34 34
33 33
32 32
31 31
30 30
29 29
28 28
27 27
26 26
25 25
24 24
Company
Company
23 23
22 22
21 21
20 20
19 19
18 18
17 17
16 16
15 15
14 14
13 13
12 12
11 11
10 10
9 9
8 8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00%
17

18. The Data
Yield Yield
Low Pressure Cold Cham ber
90th 90t h
M edian M edian
10th 10t h
38 38
37 37
36 36
35 35
34 34
33 33
32 32
31 31
30 30
29 29
28 28
27 27
26 26
25 25
24 24
Company
Company
23 23
22 22
21 21
20 20
19 19
18 18
17 17
16 16
15 15
14 14
13 13
12 12
11 11
10 10
9 9
8 8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
50.00% 55.00% 60.00% 65.00% 70.00% 75.00% 0.00% 20.00% 40.00% 60.00% 80.00% 100.00%
18

19. Dross
Z n D rB ss Per cent ag e er cent ag e
o r ass D r o ss P
A l D r o ss P er cent ag e
90t h 90t h
90t h
M edian edian
M
M edian 1 h 1 h
0t 0t
1 h
0t 38 38
38 37
36 37
37
36 35 36
35 34 35
34 33 34
33 32 33
32
31 31 32
30 31
30
29 30
29
28 28 29
27 27 28
26 26 27
25 25 26
24 25
Company
24
Company
23 23 24
Company
22 22
21
23
20 21 22
19 20 21
18 19 20
1 7 18 19
16 1 7 18
1 5 16 1 7
14 1 5
13 16
14
12 13 1 5
11 14
12
10 13
9 11
10 12
8 11
7 9
6 8 10
5 7 9
4 6 8
3 5 7
2 4 6
1 3 5
2 4
0.00% 1 3 5.00% 10.00% 15.00%
2
0.00% 1 2.00% 4.00% 6.00% 8.00% 10.00% 12.00%
0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00%
19

20. 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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21. Types of Foundries
Data Collected from
Are you still with me?
21

22. 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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23. The Costs of Energy in SA
R/GJ
10th percentile Average 90th percentile 10th percentile Median 90th percentile
Electricity 70 234 275 R/kWh 0.2545 0.8457 0.9908
Natural Gas 123 158 196 R/GJ 123.15 158.37 196.36
Parafin 158 175 192 R/l 4.58 5.06 5.55
Coke 222 222 222 R/kg 8.23 8.23 8.23
Diesel 98 196 270 R/l 2.68 5.37 7.40
Average Unit Cost of Different Energy Types in South Africa [R/GJ]
LPG 206 287 376 R/kg 4.46 6.20 8.13
Oil - HFO toOil - HFO to Used Oil
Used Oil 63 129 195 R/l 1.64 3.34 5.05
LPG [kg]
Diesel(litres)
90th Percentile
Coke(kg) Median
10th Percentile
Parafin(litres)
Natural Gas
Electricity [kWh]
0 50 100 150 200 250 300 350 400
R/GJ
23

24. 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%)
24

25. 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
25

26. Real Energy Cost to Heat Metal wrt Furnace type
Efficiency R/Metal GJ
Energy Source Furnace Type Low High High Low
Electric Resistance 50% 80% R 470 R 294
Induction 59% 76% R 398 R 309
Natural Gas Reverbatory (Radiant Roof) 10% 35% R 1,584 R 452
Electricity Costs for 2008 – Plus 25% for 2009
Stack 40% 45% R 396 R 352
Plus?? For 2010,11,12
Crucible 7% 19% R 2,262 R 834
Paraffin Reverbatory (Radiant Roof)
Electricity, Plus 25%-R 1,756 to R367
10% 35%
R587 R 502
- R498 to R386
Stack 40% 45% R 439 R 390
Crucible 7% 19% R 2,508 R 924
Diesel Reverbatory (Radiant Roof) 10% 35% R 1,966 R 562
Stack 40% 45% R 492 R 437
Crucible 7% 19% R 2,809 R 1,035
LPG Reverbatory (Radiant Roof) 10% 35% R 2,871 R 820
Stack 40% 45% R 718 R 638
Crucible 7% 19% R 4,102 R 1,511
Oil HFO/Recycled Reverbatory (Radiant Roof) 10% 35% R 1,298 R 371
Stack 40% 45% R 324 R 288
Crucible 7% 19% R 1,854 R 683
Coke Cupola 40% 50% R 556 R 444
Pit furnace 5% 12% R 4,444 R 1,852
26

27. Real Energy Cost to Heat Metal wrt Furnace type
High Cost (low efficiency) Low Cost (High Efficiency)
Coke Pit furnace 1,852
4,444
444
Coke Cupola 556
Oil Crucible 683
1,854
Oil Stack 288
324
Oil Reverbatory (Radiant Roof) 371
1,298
LPG Crucible 1,511
4,102
LPG Stack 638
718
LPG Reverbatory (Radiant Roof) 820
2,871
1,035
Diesel Crucible 2,809
437
Diesel Stack 492
562
Diesel Reverbatory (Radiant Roof) 1,966
924
Parafinn Crucible 2,508
390
Paraffin Stack 439
502
Paraffin Reverbatory (Radiant Roof) 1,756
834
Natural Gas Crucible 2,262
352
Natural Gas Stack 396
452
Natural Gas Reverbatory (Radiant Roof) 1,584
309
Electric Induction 398
294
Electric Resistance 470
0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000
R / Metal GJ
27

28. 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
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