An Overview of of Energy Efficiency and Future Needs for Aluminum Industry in Process Heating Dr. Subodh Das Secat, Inc

Transcription

1 An Overview of of Energy Efficiency and Future Needs for Aluminum Industry in Process Heating By Dr. Subodh Das Secat, Inc October 19 th, 2004

2 Energy Intensive Production Processes for Aluminum Industry Oct. 19, 2004 S. K. Das 2

3 U.S. FORECASTED GROWTH OF ALUMINUM INDUSTRY SHIPMENTS (000 METRIC TONS) 30,000 25,000 20,000 15,000 10,000 5,000 ACTUAL 2004 SECAT, INC. FORECAST (e) 2020 (e) 2030 (e) ROLLED CAST EXTRUDED OTHER Oct. 19, 2004 S. K. Das 3 SOURCE: ALUMINUM ASSOCIATION & SECAT, INC. - FORECAST

4 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//Fabrication.

5 NUMBER OF PRIMARY SMELTING PLANTS IN THE U.S SMELTERS OPERATING Alcoa 2 Century 1 Alcan 1 Norandal 2003: Fourteen (14) Smelters Operating Best Case (6) Worst Case (3) Ormet 1 Columbia Falls (e) 2020 (e) SOURCE: LIGHT METAL AGE & SECAT, INC. - FORECAST Oct. 19, 2004 S. K. Das 5

6 THE U.S. GROWTH IN RE-MELTING (000 METRIC TONS) 20,000 15,000 10,000 ACTUAL 2004 SECAT INC. FORECAST RE-MELTED IMPORTED INGOT NEW SCRAP 5,000 RECYCLE SCRAP (e) 2020 (e) 2030 (e) RECYCLE SCRAP NEW SCRAP RE-MELTED INGOT Oct. 19, 2004 S. K. Das 6 SOURCE: SECAT, INC.

7 GROWTH OF RE-MELTING IN THE U.S. (000 METRIC TONS) 20,000 18,000 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2, (e) 2020 (e) 2030 (e) RE-MELTING SMELTING Oct. 19, 2004 S. K. Das 7 SOURCE: SECAT, INC.

8 ENERGY REQUIRED SMELTING VS. RE-MELTING SMELTING (BTU PER POUND) RE-MELTING (BTU PER POUND) THEORETICAL MINIMUM 10, CURRENT AVERAGE 26,000 2,200 PRACTICALLY ACHIEVABLE 20, ENERGY EFFICIENCY SAVINGS OPPORTUNITY (BTUs / LB.) 6,000 1,275 Oct. 19, 2004 S. K. Das 8 SOURCE: CHOATE /GREEN/DOE

9 U.S. ENERGY EFFICIENCY SAVINGS OPPORTUNITIES RE-MELTING VS. SMELTING (U.S. - TRILLIONS BTUs PER YEAR) CROSSOVER POINT = (e) 2020 (e) 2030 (e) RE-MELTING SMELTING Oct. 19, 2004 S. K. Das 9 SOURCE:SECAT, INC.

10 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.

11 Energy Use by the U.S. Aluminum Industry Total U.S. Energy Use Trillion (10^12) Btu/year in Aluminum production 350 Trillion (10^12 Btu/year) Trillion (10^12 Btu/year) Alumina Refining Anode Production Aluminum Smelting Primary Secondary Rolling Extrusion Shape 0.0 Alumina Refining Anode Production Primary Secondary Rolling Extrusion Shape Oct. 19, 2004 S. K. Das 11

12 Energy Use per Lb. of Aluminum Production for the U.S. Aluminum Industry Energy Required (Btu/Lb. of Aluminum Produced) for Aluminum Industry Processes 60,000 50,000 Btu/Lb. of Aluminum 14,000 12,000 10,000 8,000 6,000 4,000 Btu/Lb. of Aluminum 40,000 30,000 20,000 10,000 - Alumina Refining Anode Production Aluminum Smelting Primary Secondary Rolling Extrusion Shape 2,000 - Alumina Refining Anode Production Primary Secondary Rolling Extrusion Shape Oct. 19, 2004 S. K. Das 12

13 Overall (Gross) Energy Efficiency for Aluminum Industry Processes Efficiency (%) 80.0% 70.0% 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% Alumina Refining Anode Aluminum Production Smelting Primary Secondary Rolling Extrusion Shape Oct. 19, 2004 S. K. Das 13

14 Use of Electricity and Fuel for Aluminum Production Processes 100% 90% Electricity Fuel 80% 70% Percentage 60% 50% 40% 30% 20% 10% 0% Alumina refining Anode production Aluminum smelting Primary Ingot Secondary Hot Rolling Cold Rolling Extrusion Shape Ingot Oct. 19, 2004 S. K. Das 14

15 Four Systems offer major energy saving opportunities in Secondary Aluminum Industry Plants Process Heating/ Burners 60% to 80% Electric Motor Systems 10% to 25% Compressed Air Systems 2% to 5% Aluminum Plant Pumping Systems 5 to 10% The numbers show the percentage of total energy used for the specific system Oct. 19, 2004 S. K. Das 15

16 Process Heating in Aluminum Production Types of Processes where Heat is Used 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 Oct. 19, 2004 S. K. Das 16

17 Process Heating Process heating consumes more than 70 % to 85% of the total energy used for the secondary aluminum industry 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 Oct. 19, 2004 S. K. Das 17

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 18

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 19

20 Major Sectors of Aluminum Industry Areas for Process Heating R&D Opportunities Bauxite Alumina (Imports) Aluminum Aluminum Refining Refining Primary Primary Aluminum Aluminum Smelters Smelters Carbon Carbon products products (Anodes, (Anodes, Cathodes) Cathodes) Primary Primary Ingot Ingot Ingot, slab (Imports) Scrap Scrap Scrap Based Based Secondary Secondary Aluminum Aluminum Smelters Smelters Secondary Melting and fabrication Semi-Fabrication Semi-Fabrication Sheet, Sheet, Plate, Plate, Foil Foil Semi-Fabrication Semi-Fabrication Other Other Products Products (extrusions, (extrusions, bars,wires bars,wires etc.) etc.) Exports End Products Fabricators Scrap Scrap Final Consumption Scrap Oct. 19, 2004 S. K. Das 20

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 21

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 Oct. 19, 2004 S. K. Das 22