7th CSI Forum - Vancouver Innovative approaches to reduce CO 2 emissions

Transcription

1 7th CSI Forum - Vancouver Innovative approaches to reduce CO 2 emissions Günther Walenta Lafarge LCR 02/10/2013

2 LAFARGE & CO 2 - Some Figures In 2012, LAFARGE produced 153 Mt cement and emitted ~94 Mt CO 2 About 65% of the CO 2 related to decarbonation of limestone and 35% from fuel combustion Between , Lafarge decreased net CO 2 emissions by 20% (from 774 to 630 kg CO 2 /t cement ) i.e. a reduction of ~25 Mt CO 2 /yr Since 2011 new commitment : minus 33% of net CO 2 emissions reduction from 1990 to 2020 Main conventional levers used to reduce CO 2 : Reduce specific heat consumption of the cement kiln Increase cementitious additions into the cement (slag, FA, pozzolans, limestone ) Substitution of fuels (animal meal, tires, shredded wastes ) Date 2

3 Some potential non conventional solutions Although the conventional industrial levers still need to be developed, we think they will soon come to a limit and that we will not be able divide our CO 2 emissions by factor 4 (by year 2050) Other non conventional means need to be developed: Carbon Capture & Sequestration (CCS) Carbon Capture & Transformation (CCT) Micro- Algae Low CO 2 clinker development: AETHER Date 3

4 Algae ponds Photo-bio-reactors (PBR) Algae growing based on Photosynthetic reaction + + CO 2 + H 2 O Biomass + O 2 Micro-algae Sunlight Bio-fuels: biodiesel / bioethanol / methanisation High value products (omega-3 ) Surface needed: ~4 km² 485 /t CO 2 avoided (without CAPEX) Total CO 2 reduction: 50% CO 2 But: Business model not v Vertical tubular PBR Significant technology breakthrough needed for industrial use Date 4

5 Lafarge s objectives for Aether : A low CO 2 clinker for all types of cement Objective: Develop a new class of clinkers for making cements with similar mechanical performances to conventional OPCs, and which can be produced in existing PC plants, while giving significantly lower CO 2 emissions (20%-30%) in production Targeting Niche products & mainstream products Not looking for specific applications, but looking to replace the ordinary clinker Ready mix, Precast Date 5

6 What is AETHER? Aether is a new, patented* class of low-co 2 cements based on BCSAF clinkers containing: Belite: C 2 S 40 75% Calcium sulfoaluminate (ye elimite): C4A3$ % Ferrite : C 2 (A,F) 5 25% *Gartner, E., and Li, G., World Patent Application WO2006/ A2 Date Page 6

7 Aether cement: CO 2 emissions and manufacturing Portland raw mix Portland clinker Aether clinker * Aether raw mix * ~35% ~14% ~3% ~3% ~43% ~0.3% LOI SiO 2 Al 2 O 3 Fe 2 O 3 CaO SO 3 C 3 S C 3 A C 2 S C 4 AF ~65% ~6% ~15% ~12% C 4 A 3 $ C 2 S C 2( A,F) ~25% ~55% ~20% LOI SiO 2 Al 2 O 3 Fe 2 O 3 CaO SO 3 ~29% ~12% ~11% ~5% ~37% ~3% Aether main characteristics vs. Portland: * a potential Aether composition Higher Alumina and SO 3 content and lower LOI of the raw mix = lower CaCO 3 No C 3 S, but C 4 A 3 $ & higher C 2 S content Date 7

8 Overview CSA and belite based binder technologies Different approaches (not exhaustive): Buzzi (NEXT) Heidelberger (BCT) Italcementi (ALIPRE) Vicat (ALPENAT) Lafarge (AETHER) Some common points: Chemistry & mineralogy different from OPC C 3 S is no longer major phase; C 2 S takes on more importance (15 to 75%) Presence of C 4 A 3 $ (15% to 70%), C 5 S 2 $, C$ Raw materials similar to OPC, but generally higher alumina needs higher raw material cost - use of alternative raw materials is preferred Wide range of compositions, allowing a high variety of properties Lower limestone & burning temperatures = lower CO 2 emissions Higher short term strength, etc, Date 8

9 Aether industrial trial 2012 Le Teil (South of France) Timing: 06/12/2012 to 18/12/2012 Rotary kiln Length ~70m ~100 Participants 2 times 5000t of good AETHER clinker produced Date Page 9

10 Aether : Experiences from Industrial trials: CO 2 emissions and manufacturing facts Aether clinkers can be produced: in kilns designed for Portland production (Lepol 2011 & Dry 2012) using similar process parameters and fuels using mainly conventional raw materials at lower temperatures ( C) than for Portland cement clinker ( C) with significantly lower energy than Portland cement clinker Aether cement grinding energy is lower than for OPC (based on lab grinding -must be confirmed industrially) The manufacturing of Aether generates 20 to 30% less CO 2 per tonne of cement than pure Portland cement (CEM (I) type) Date 10

11 Ongoing & next steps Evaluate clinker & cement properties Mineralogy & Chemistry Standard motar & Concrete testing Durability testing Creation of suitable standards Identify most promising AETHER applications Date 11

12 Results AETHER TM Concrete tests Precast Concrete application Slump life: 45 min -1 hour Slump Class: S3-S4 Strenghts: 6 hours: 20 MPa (without heating 24 hours: 27 MPa 7 days: 41 MPa 28 days: 48 MPa Date 12

13 Durability Results AETHER TM Concrete Strength development and dimensional variations Ongoing study with Lafarge - BRE (British Research Establishment) with European Union support (Life+ project) Strength development (will continue for 10 years) o in water (40, 68, 95 F, ie: 5, 20, 35 C), o in air (68 F / 20 C, 65%RH) All results comparable to OPC (6 months) time 0 1y Dimensional variations Results (1year): Drying shrinkage reduced 50% dl/l µm/m Aether Portland Typical mix for «wet precast» W/C=0.4 Date 13

14 Resistance to agressive medium Wear rating Durability Results AETHER TM Concrete min. equivalent to OPC (still in progress) o Class 5 sulfate at 5 C o 3% citric acid at 20 C Use of alkali reactive aggregates: In progress Possibility to use embedded steel reinforcement: Protective passivating layer on the surface of embedded steel rebar confirmed further study foreseen (PhD) Date 14

15 Durability Results AETHER TM Concrete Risk of corrosion of embedded steel corrosion Resistance to carbonation for laboratory & natural exposure Carbonation equivalent to a blended Portland cement with similar CO 2 saving Resistance to chloride ingress Matches equivalent OPC concretes Date 15

16 Aether : Conclusion AETHER cements based on clinkers containing belite, calcium sulfoaluminate and ferrite seem to be a promising alternative to Portland cements. 20%-30% Reduction of CO 2 emissions relative to Portland cements Use of similar raw materials and production possible in existing industrial installations Similar concrete performance to Portland cements But more research is needed on process, hydration and durability, in order to develop appropriate standards, before Aether cements can be considered a largescale alternative to Portland cement. Date 16

17 2011 Team AETHER TM before returning to the individual working groups: Nationalities: Brazil, Canada, China, Germany, England, France, Austria, Spain Date 17

18 Thank you! Discussion Date 18