Alloying elements in the global aluminium cycle

Transcription

1 Presented at System Dynamics Society Swiss chapter meeting in Zürich, 24 March 2015 Alloying elements in the global aluminium cycle Amund N. Løvik Supervisor: Daniel B. Müller Industrial Ecology programme Dept. of Energy and Process Engineering

2 Contents Contents 1. Background 2. Methods 3. Results 4. Discussion

3 1. Background Aluminium industry facts Demand growth ca. 3% per year 1-2% of world greenhouse gas emissions Ca 25% recycled content in new products Demand for semi-fabricated aluminium products Source: International Aluminium Institute

4 1. Background Use of aluminium Transport + buildings > 50% of demand Transport + beverage cans > 70% of post-consumer scrap Demand for aluminium in finished products Other Recovered aluminium from EOL scrap (estimated) End-use consumption (kt) Consumer durables Electrical Machinery and equipment Packaging Transport 8% 8% 10% 5% 23% 8% 39% Buildings and construction Source: International Aluminium Institute

5 1. Background Emission pathways of the global aluminium cycle [Liu et al. 2013] GHG emissions until 2100 Future: increased recycling lower emissions GHG emissions of the aluminium cycle Liu, G.; Bangs, C. E.; Müller, D. B., Stock dynamics and emission pathways of the global aluminium cycle. Nature Climate Change 2013, 3,

6 1. Background Today: 25% old scrap cascading Future: 60% old scrap closed loops?

7 1. Background Why look at cars? 1. One of the largest end uses 2. Largest scrap source 3. Diverse and growing use of aluminium alloys 4. Bottom reservoir for scrap!

8 1. Background Research questions Which interventions, or combination of interventions can most effectively [ ] mitigate scrap surplus? Possible interventions Dismantling Automated alloy sorting (LIBS) Using scrap in safety-relevant components Løvik, Amund N., Roja Modaresi, and Daniel B. Müller. Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements. Environmental Science & Technology 48, no. 8 (April 15, 2014.

9 2. Methods: Material flow analysis (MFA) Procedure Define a system of processes, material flows, and material stocks Quantify the mass of flows and stocks Metal cycle Mining Metal production Fabrication Use Waste mgt.

10 2. Methods: Dynamic material flow analysis Calculate future scrap flows based on lifetime distribution functions I Input of cohort t I(t ) O Output of cohort t t=t Input year Stock t=t Output year S Stock of cohort t t=t year

11 2. Methods: System definition Løvik, Amund N., Roja Modaresi, and Daniel B. Müller. Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements. Environmental Science & Technology 48, no. 8 (April 15, 2014.)

12 2. Methods: Mathematical model Parameters Mathematical model System variables P CpC λ σ SS CGW AGR CAL CAU CE CR CGD IC RY SY ASA ASR S 5 X 01 X 08 X 10 X 12 X 20 X 23 X 34 X 45 X 50 X 56 X 67 X 68 X 70 X 71

13 2. Methods: Quantification of parameters Aluminium in car components Population Cars per capita in use

14 2. Methods: Quantification of parameters Composition of alloys Level of dismantling Al Si Fe Cu Mn Mg Cr Ni Zn Ti 1070A A Low dismantling High dismantling Body-in-white 0% 35% Closures 10% 80% Bumper and 50% 75% crash box Heat shields 0% 50% Heat exchanger 30% 70% Engine block 50% 100% and cylinder head Suspension 0% 50% frame Suspension arm 0% 25% and steering Wheels 100% 100% Transmission 0% 25% and driveline Brake 0% 0% components Other engine 0% 75% comp. Other steering 0% 0%

15 3. Results Historical use of Al in car components Future scrap composition Løvik, Amund N., Roja Modaresi, and Daniel B. Müller. Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements. Environmental Science & Technology 48, no. 8 (April 15, 2014.)

16 3. Results Cascading diagram of alloys Low dismantling High dismantling Løvik, Amund N., Roja Modaresi, and Daniel B. Müller. Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements. Environmental Science & Technology 48, no. 8 (April 15, 2014.)

17 3. Results Primary/secondary demand and scrap surplus New automotive Al / surplus scrap (Mt/year) Low dismantling Without alloy sorting High dismantling Without alloy sorting Low dismantling With alloy sorting High dismantling With alloy sorting Without recycling to safetyrelevant components With recycling to safetyrelevant components Løvik, Amund N., Roja Modaresi, and Daniel B. Müller. Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements. Environmental Science & Technology 48, no. 8 (April 15, 2014.)

18 4. Discussion Model limitations: Simplifications lead to optimistic results Simplified alloy system Only one external impurity (Fe) No economics Conclusions: Recycling into safety-relevant cast components is necessary and possible (e.g. wheel-to-wheel recycling) Must be combined with better scrap segregation Dismantling gives similar results as alloy sorting