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An Overview of of Energy Efficiency and Future Needs for Aluminum
Industry in Process Heating
By
Dr. Subodh DasSecat, Inc
October 19th, 2004
Oct. 19, 2004 S. K. Das 2
Energy Intensive Production Processes for Aluminum Industry
Oct. 19, 2004 S. K. Das 3
U.S. FORECASTED GROWTH OF ALUMINUM INDUSTRY SHIPMENTS
(000 METRIC TONS)
0
5,000
10,000
15,000
20,000
25,000
30,000
1980 1990 2000 2010 (e) 2020 (e) 2030 (e)
ROLLED CAST EXTRUDED OTHER
SOURCE: ALUMINUM ASSOCIATION &SECAT, INC. - FORECAST
SECAT, INC. FORECASTACTUAL 2004
U.S. ALUMINUM INDUSTRY TRENDS
• CLOSED: All bauxite mining.
• DECLINING: 3 alumina refineries operating.
• CURTAILED: Only 14 smelters operating.• 7 Smelters are operating at full capacity.
• 7 Smelters are operating at 63% of combined capacity.
• REMAINING: Re-melting/Casting/Fabrication.
Oct. 19, 2004 S. K. Das 5
NUMBER OF PRIMARY SMELTING PLANTS IN THE U.S.
0
5
10
15
20
25
30
35
1980 1990 2000 2003 2010 (e) 2020 (e)
2003: Fourteen (14)
Smelters Operating
Best Case (6)Worst Case (3)
SMELTERS OPERATING - 2003
• 8 Alcoa
• 2 Century
• 1 Alcan
• 1 Norandal
• 1 Ormet
• 1 Columbia Falls
SOURCE: LIGHT METAL AGE
& SECAT, INC. - FORECAST
Oct. 19, 2004 S. K. Das 6
THE U.S. GROWTH IN RE-MELTING(000 METRIC TONS)
0
5,000
10,000
15,000
20,000
1980 1990 2000 2010 (e) 2020 (e) 2030 (e)
RECYCLE SCRAP NEW SCRAP RE-MELTED INGOT
NEW SCRAP
RE-MELTEDIMPORTED INGOT
RECYCLE SCRAP
SECAT INC. FORECASTACTUAL
SOURCE: SECAT, INC.
2004
Oct. 19, 2004 S. K. Das 7
GROWTH OF RE-MELTING IN THE U.S.
(000 METRIC TONS)
02,0004,0006,0008,000
10,00012,00014,00016,00018,00020,000
1980 1990 2000 2010 (e) 2020 (e) 2030 (e)
RE-MELTING SMELTING
SOURCE: SECAT, INC.
Oct. 19, 2004 S. K. Das 8
ENERGY REQUIREDSMELTING VS. RE-MELTING
SMELTING RE-MELTING
(BTU PER POUND)
(BTU PER POUND)
THEORETICAL MINIMUM
10,200
510
CURRENT AVERAGE
26,000
2,200
PRACTICALLY ACHIEVABLE
20,000
925
ENERGY EFFICIENCY SAVINGS OPPORTUNITY (BTUs / LB.)
6,000
1,275
SOURCE: CHOATE /GREEN/DOE
Oct. 19, 2004 S. K. Das 9
U.S. ENERGY EFFICIENCY SAVINGS OPPORTUNITIES
RE-MELTING VS. SMELTING(U.S. - TRILLIONS BTUs PER YEAR)
0
10
20
30
40
50
60
70
1980 1990 2000 2010 (e) 2020 (e) 2030 (e)
RE-MELTING SMELTINGSOURCE:SECAT, INC.
CROSSOVER POINT = 2006
CONCLUSION
Going forward from 2004, the best opportunity for improving energy efficiency and lowering energy consumption in the U.S. Aluminum Industry is by focusing research upon re-melting.
Oct. 19, 2004 S. K. Das 11
0.0
10.0
20.0
30.0
40.0
50.0
60.0
AluminaRefining
AnodeProduction
PrimaryCasting
SecondaryCasting
Rolling Extrusion ShapeCasting
Trill
ion
(10^
12 B
tu/y
ear)
Total U.S. Energy Use Trillion (10^12) Btu/yearin Aluminum production
0
50
100
150
200
250
300
350
AluminaRefining
AnodeProduction
AluminumSmelting
PrimaryCasting
SecondaryCasting
Rolling Extrusion ShapeCasting
Trill
ion
(10^
12 B
tu/y
ear)
Energy Use by the U.S. Aluminum Industry
Oct. 19, 2004 S. K. Das 12
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
AluminaRefining
AnodeProduction
PrimaryCasting
SecondaryCasting
Rolling Extrusion Shape Casting
Btu
/Lb
. o
f A
lum
inu
m
Energy Required (Btu/Lb. of Aluminum Produced) for Aluminum Industry Processes
-
10,000
20,000
30,000
40,000
50,000
60,000
AluminaRefining
AnodeProduction
AluminumSmelting
PrimaryCasting
SecondaryCasting
Rolling Extrusion ShapeCasting
Btu
/Lb.
of A
lum
inum
Energy Use per Lb. of Aluminum Production for the U.S. Aluminum Industry
Oct. 19, 2004 S. K. Das 13
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
AluminaRefining
AnodeProduction
AluminumSmelting
PrimaryCasting
SecondaryCasting
Rolling Extrusion ShapeCasting
Effic
ienc
y (%
)
Overall (Gross) Energy Efficiency for Aluminum Industry Processes
Oct. 19, 2004 S. K. Das 14
Use of Electricity and Fuel for Aluminum Production Processes
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Aluminarefining
Anodeproduction
Aluminumsmelting
Primary IngotCasting
SecondaryIngot Casting
Hot Rolling Cold Rolling Extrusion ShapeCasting
Perc
enta
ge
Electricity
Fuel
Oct. 19, 2004 S. K. Das 15
Four Systems offer major energy saving opportunities in Secondary Aluminum Industry Plants
Pumping Systems
CompressedAir Systems
Process Heating/ Burners Electric Motor
Systems
AluminumPlant
60% to
80%
10% to
25%
2% to 5%
5to
10%
The numbers show the percentage of total energy used for the specific system
Oct. 19, 2004 S. K. Das 16
• Primary Aluminum Production– Drying – Calcining– Heating - Anode baking
• Secondary Aluminum Production– Metal Melting– Metal Heating– Metal Heat Treating
• Fabrication and Finishing – Metal Heating– Fluid Heating– Heat Treating– Drying– Curing and Forming
Process Heating in Aluminum Production
Types of Processes where Heat is Used
Oct. 19, 2004 S. K. Das 17
Process Heating
• Process heating systems are used for melting, heating, heat treatment, drying, smelting, roasting, fluid heating etc.
• Process heating equipment include furnaces, melters, ovens, heaters, dryers etc.
• These equipment use fuel (natural gas, oil etc.) and electricity as source of energy
• Process heating offers significant (usually more than 50%) energy savings through application of new developments through R&D for heating equipment
Process heating consumes more than 70 % to 85% of the total energy used for the secondary aluminum industry
Oct. 19, 2004 S. K. Das 18
Process Heating Energy Issues
• Low efficacy of furnaces
• Excessive maintenance of furnace parts (refractories, burners, radiant tubes, recuperators etc.)
• Availability of simple and reliable sensors and controls for flue gas composition (NOx, O2 etc.)
• High turn-down, low NOx burners
• Models and tools to predict heating and soak time for a variety of sizes and shapes in heating/heat-treating furnaces
• Life of recuperators for air heating
Oct. 19, 2004 S. K. Das 19
Environmental Issues
• NOx emissions from burners and furnaces
• Particulate emissions from furnaces
• Emission from recycled scrap processing (volatiles, inorganic etc.)
• Emissions from coating processes (volatiles, fumes etc.)
• Dross processing and residual disposal
Oct. 19, 2004 S. K. Das 20
Major Sectors of Aluminum Industry Areas for Process Heating R&D Opportunities
Aluminum Refining
Aluminum Refining
Primary Aluminum Smelters
Primary Aluminum Smelters
Bauxite
Alumina (Imports)
Carbon products (Anodes, Cathodes)
Carbon products (Anodes, Cathodes)
Scrap Based Secondary Aluminum
Smelters
Scrap Based Secondary Aluminum
Smelters
Ingot, slab (Imports)
Semi-FabricationOther Products
(extrusions, bars,wires etc.)
Semi-FabricationOther Products
(extrusions, bars,wires etc.)Semi-FabricationSheet, Plate, Foil
Semi-FabricationSheet, Plate, Foil
End Products Fabricators
Final Consumption
Exports
Scrap
Scrap
Scrap
Scrap
Primary Ingot Casting
Primary Ingot Casting
Secondary Melting and fabrication
Oct. 19, 2004 S. K. Das 21
Research Priorities for the Aluminum Industry
• Most of the research should be done in recycling and remelting areas• Develop and design aluminum remelting furnace for the future that
minimizes melt loss, increase cost effectiveness, increase safety, improve fuel/energy efficiency, improve melt rates and reduce emissions
• Develop a low cost process for metal purification of primary alloys from recycled scrap. This includes methods to remove specific impurities such as Mg, Fe, Pb, Li, Si, and Ti to produce high-quality metal from mixed scrap.
• Develop new secondary alloys that better match scrap to specifications for increased utilization. Coupled with this is a goal to develop manufacturing processes for scrap-tolerant alloys, such as spray rolling and other rapid solidification processes
• Minimize the loss of aluminum to oxidation and dross formation during remelting. Priorities include developing a more complete understanding of oxidation mechanisms and developing processes that more effectively separate metal from dross or salt cakes.
Oct. 19, 2004 S. K. Das 22
Research Priorities for the Process Heating in Aluminum Industry
• Efficient and long-life waste heat recovery systems for combustion air preheating
• High efficiency, low-emission heating systems• Improved systems for molten-metal recirculation• Sensors and control system for melting, heating and
aluminum heat treating furnaces• Emission control systems for furnaces• Improved metallic and refractory materials for furnaces,
burners, radiant tubes etc.• Low cost oxygen supply• Fuel or energy source flexibility for heating• Low dross or near-zero melt loss heating system
