DEVELOPMENTS NEEDED IN THE PRODUCTION AND USE OF CEMENT FOR LARGE REDUCTIONS IN CO 2 EMISSIONS BY 2050 DUNCAN HERFORT

Transcription

1 DEVELOPMENTS NEEDED IN THE PRODUCTION AND USE OF CEMENT FOR LARGE REDUCTIONS IN CO 2 EMISSIONS BY 2050 DUNCAN HERFORT

2 Corresponds to stabilization of CO 2 concentrations at c. 500 ppm and temperature increase of 2.4 C, and acidification of ocean above solubility product for aragonite.

3 From the IEA: Four approaches can be applied to increase the energy efficiency and reduce CO 2 emissions in the cement industry: (1) increase the process energy efficiency, (2) use coal fuel substitutes, (3) capture and store CO 2 (4) develop new cement types that reduce the use of cement clinker. MRS BULLETIN VOLUME 33 APRIL Harnessing Materials for Energy

4 2500 Mt 5000 Mt

5 At 0.81 tco 2 /t cement = 2000 Mt CO 2 emission Increasing to 4000 Mt

6 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete 40% SCM for same concrete performance performance Emissions must ( t CO 2 ) effectively be reduced from a 1/51/3 of of RM RM COCO2 2 recarbonated (0.34 business 10 9 t CO 2 as ) usual scenario of 4 Gt to 1 Gt 2/5 of CO 2 emissions captured and 1/4 stored of CO2 (0.83 emissions 10 9 t CO stored 2 ) and captured Serie

7 CO 2 EMISSIONS FROM CLINKER PRODUCTION SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

8 CO 2 EMISSIONS FROM CLINKER PRODCUTION RAW MATERIALS KILN EFFICIENCY LOW CARBON FUELS SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

9 raw materials

10 S Qz rich sand Argillaceous Portland cement clinker C 3 S 2 C 2 S CS CAS 2 A 3 S 2 C 3 S C 2 AS Limestone C C 3 A C 12 A 7 CA CA 2 CA 6 A

11 belite clinker RM CO 2 emissions reduced by about 10%. S Qz rich sand Argillaceous Belite rich Portland cement clinker C 3 S 2 C 2 S CS CAS 2 A 3 S 2 C 3 S C 2 AS Limestone C C 3 A C 12 A 7 CA CA 2 CA 6 A

12 Further reductions in the Ca content form SiO 2 - saturated silicates which are non-hydraulic unless they are quenched to form a glass. S Qz rich sand Argillaceous Di and chain silicates CS CAS 2 C 3 S 2 C 2 S A 3 S 2 C 3 S C 2 AS Limestone C C 3 A C 12 A 7 CA CA 2 CA 6 A

13 Anorthosites S Qz rich sand Argillaceous Anorthosite Portland cement clinker C 3 S 2 C 2 S CS CAS 2 A 3 S 2 C 3 S C 2 AS Limestone C C 3 A C 12 A 7 CA CA 2 CA 6 A

14

15 BFS and Class C fly ash S Quartz rich sand Argillaceous RMs Portland cement clinker C 3 S 2 C 2 S CS CAS 2 A 3 S 2 Class C PFA C 3 S C 2 AS BFS Limestone C C 3 A C 12 A 7 CA CA 2 CA 6 A

16 LOW CARBON FUELS AND KILN EFFICIENCY LOW CARBON FUELS AND KILN EFFICIENCY

17 t CO2 emission / t clinker CO 2 emissions from FD and RM fuels as function of heat consumption Efficient dry 0.28 European Average 0.34 Efficient wet * *coal CO 2 emissions from clinker production as a function of kiln efficiency 0.42 Global Average Inefficient wet 100 kwh/t cement = 0.1 t CO Heat heat consumption, consumption, GJ/t kcal/kg clinker 0.80 Coal Raw materials

18 Total consumption TJ= *six countries consumed between 40% & 90% of alternative fuels Energy Consumption (Average CEMBUREAU) Alternative Fuels * 15.4% Coal 20,8% Global average of 5% AF Gas 0,9% HVFO 0,9% Fuel Oil 2,2% Lignite/Shale/Schiste 7,9% Coal & Petcoke 12,8% Petcoke 39,1% CEMBUREAU EL 5 March 2008

19 20,0 18,0 16,0 14,0 12,0 10,0 8,0 6,0 4,0 2,0 0,0 Alternative fuels used in cement kilns (Average CEMBUREAU) Plastics RDF Rubber/Tyres Industrial sludges Municipal Sewage sludges Animal meal, fats Coal/Carbon Waste Agricultural waste Solid alternative fuels (impregnated saw dust) Solvents and related waste Oil and oily waste Others % Wood, paper, cardboard Textiles Plastics d, paper, cardboard Textiles UREAU EL 5 June 2008 Used tires with typical biomass content of 25 RDF with typical biomass content of 35%

20 20,0 18,0 16,0 14,0 12,0 10,0 8,0 6,0 4,0 2,0 0,0 Alternative fuels used in cement kilns (Average CEMBUREAU) Plastics RDF Rubber/Tyres Industrial sludges Municipal Sewage sludges Animal meal, fats Coal/Carbon Waste Agricultural waste Solid alternative fuels (impregnated saw dust) Solvents and related waste Oil and oily waste Others % Wood, paper, cardboard Textiles Plastics d, paper, cardboard Textiles UREAU EL 5 June 2008 In all 34% of AFs can be classified as biomass = 5% of total fuel

21 t CO2 emission / t clinker CO 2 emissions from FD and RM fuels as function of heat consumption Efficient dry 0.28 European Average 0.34 Efficient wet * *coal CO 2 emissions from clinker production as a function of kiln efficiency 0.42 Global Average Inefficient wet Heat consumption, GJ/t clinker heat consumption, kcal/kg 0.80 Coal Raw materials

22 t CO2 emission / t clinker CO 2 emissions from FD and RM fuels as function of heat consumption Efficient dry 0.20 European Average Efficient wet 0.53 * *coal CO 2 emissions from clinker production as a function of kiln efficiency Global Average FD CO 2 emission reduced to 0.20 t/t clinker Inefficient wet 20/20 biomass NG scenario Heat consumption, GJ/t clinker heat consumption, kcal/kg Coal Raw materials

23 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete performance 1/3 of RM CO2 recarbonated 1/4 of CO2 emissions stored and captured Serie

24 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete performance 1/3 of RM CO2 recarbonated This will happen anyway if an effective C&T system is in place 1/4 of CO2 emissions stored and captured From an R&D perspective better understanding of the role played by minor and trace elements is needed, including P 2 O 5, leaching of heavy metals etc. Serie

25 CO 2 EMISSIONS FROM CLINKER PRODCUTION RAW MATERIALS KILN EFFICIENCY LOW CARBON FUELS SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

26 Availability of supplementary cementitious materials x Metakaolin Rice husk ash Silica fume Burnt shale Natural pozzolana Blast furnace slag IEA production data published 2008: Cement 2500 tpa Fly ash 300 tpa Used in cement BF slag 220 tpa Reserve i.e. max 20% of cement Fly ash Cement Mill. tons/year 2003 figures

27

28 silica gel 20% Silica fume clays pozzolans C-S-H ss C 1.7 SH x C 0.8 SH y 70% GBFS 35% basaltic pozzolan 25% granitic pozzolan 25% calcined clay or PFA stratlingite CH C 3 A.CS.H 12 C 3 A.CC.H 12 C 3 A.3CS.H 32 gibsite C 3 A Portland cement

29 CEM I 32% Others 28% CEM II L 23% CEM II M 17%

30 140 CEM I CEM III,IV,V & II without limestone CEM IIM CEM II L 120 million tonnes unspecified 32,5 42,5 52,5 strength class

31 gypsum CaSO 4 + CSH + CH + FH 3 + pore solution ettringite thaumasite monosulfate Ms-ss Reduced porosity Increased porosity C 4 AH 13 C 3 A Hemicarbonate Monocarbonate calcite CaCO 3

32 Correlation: Porosity Compressive Strength (exp. Data by D. Herfort, Aalborg cement) 15 compressive strength measured relative change of porosity and compressive strength [%] total porosity calculated increase decrease amount of CaCO 3 added [wt.-%] Very good correlation between predicted changes of relative porosity and measured compressive strength

33 15 compressive strength measured relative change of porosity and compressive strength [%] total porosity calculated increase decrease amount of CaCO 3 added [wt.-%] Very good correlation between predicted changes of relative porosity and measured compressive strength

34 silica gel 20% Silica fume clays pozzolans C-S-H ss C 1.7 SH x C 0.8 SH y 70% GBFS 35% basaltic pozzolan 25% granitic pozzolan 25% calcined clay or PFA stratlingite CH C 3 A.CS.H 12 C 3 A.CC.H 12 C 3 A.3CS.H 32 gibsite C 3 A Portland cement

35 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete 40% clinker replacement for same performance concrete performance ( t CO 2 ) 1/3 of RM CO2 recarbonated 1/4 of CO2 emissions stored and captured Serie

36 4 Global CO2 emission from cement production 10 9 tonne pa This won t happen on its own Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete 40% clinker replacement for same performance concrete performance ( t CO 2 ) 1/3 of RM CO2 recarbonated 1/4 of CO2 emissions stored and captured Serie1 The mineralogical systems have to be developed to maximize the use of SCMs for fit for purpose concrete performance.

37 CO 2 EMISSIONS FROM CLINKER PRODCUTION RAW MATERIALS KILN EFFICIENCY LOW CARBON FUELS SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

38 CONCRETE CARBONATION

39

40 Actual recycled aggregate, stockpiled 1 year

41 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete 40% performance SCM for same concrete performance ( t CO 2 ) 1/51/3 of of RM RM COCO2 recarbonated 2 recarbonated ( t CO 2 ) 1/4 of CO2 emissions stored and captured Serie

42 CO 2 EMISSIONS FROM CLINKER PRODCUTION RAW MATERIALS KILN EFFICIENCY LOW CARBON FUELS SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

43 CARBON CAPTURE AND STORAGE

44 POST COMBUSTION Adds $50 to $100/t CO 2 avoided to cost of production Residual exhaust gas Air Fuel Cement kiln CO 2 separation (amine absorption process) (a) Clinker Raw materials CO 2

45 OXYFUEL N 2 Air Oxygen separation Gas recycling O 2 Fuel Cement kiln CO 2 condensation (b) Clinker Raw materials CO 2 H 2 O

46 CARBON CAPTURE AND STORAGE Geological storage possible where suitable anticlines capped by impervious rock exist

47 CARBON CAPTURE AND STORAGE Ocean storage not an option owing to acidification, except where AWL is involved (bicarbonate solution rather than carbonic acid by scrubbing flue gasses with limestone)

48 Global CO2 emission from cement production 10 9 tonne pa Improved improved kiln kiln efficiency, use of bio fuels biofuel,n.gas & natural gas where (0.93 practicable 10 9 t CO 2 ) 40% SMC for same concrete 40% SCM for same concrete performance performance ( t CO 2 ) 1/51/3 of of RM RM COCO2 2 recarbonated ( t CO 2 ) 2/5 of CO 2 emissions captured and 1/4 stored of CO2 (0.83 emissions 10 9 t CO stored 2 ) and captured Serie

49 CO 2 EMISSIONS FROM CLINKER PRODCUTION RAW MATERIALS KILN EFFICIENCY LOW CARBON FUELS SCMS CONCRETE CARBONATION CARBON CAPTURE & STORAGE ALKALI ACTIVATED ALUMINO SILICATES

50 ALKALI ACTIVATED ALUMINO-SILICATE CEMENTS alkali-activated systems are claimed to require 60% less energy to produce than PC and to reduce CO 2 emissions by 80%

51 SiO 2 PC high in Ca high in CO 2 cristobalite tridymite CS wollastonite anorthite mullite Earth s crust low in Ca low in CO 2 rankinite C 3 S 2 CAS 2 C 3 S C 2 S belite alite gehlenite C 2 AS corundum A 3 S ºC 2200ºC lime 2000ºC 1800ºC CA CA 2 CA 6 CaO C 3 A C 12 A 7 CA CA 2 CA 6 Al 2 O 3 C 12 A 7

52 SiO 2 PC high in Ca high in CO 2 cristobalite tridymite CS wollastonite anorthite mullite Earth s crust Consisting of 60% feldspars rankinite C 3 S 2 CAS 2 C 3 S C 2 S belite alite gehlenite C 2 AS corundum A 3 S ºC 2200ºC lime 2000ºC 1800ºC CA CA 2 CA 6 CaO C 3 A C 12 A 7 CA CA 2 CA 6 Al 2 O 3 C 12 A 7

53 C 1.7 SH x 20% Silica fume C 0.8 SH y C-S-H ss silica gel Clays, PFA etc. from weathering of feldspars used as SCM or as geopolymer if alkalis topped up to original alkali/aluminate balance in feldspar 70% GBFS 35% basaltic pozzolan 25% granitic pozzolan 25% calcined clay or PFA stratlingite CH C 3 A.CS.H 12 C 3 A.CC.H 12 C 3 A.3CS.H 32 gibsite C 3 A Portland cement

54 Instead of feldspars which are only stable at high temperature low T, much more open framework silicates, are formed which are closely related to the zeolites.

55 Despite the high alkali content, the alkalis are tied up in the silicates and a high ph pore solution cannot be maintained for protection of steel reinforcement against corrosion, which makes hybrid PC-alkali activated AS interesting.

56 Hydrate phase assemblage at high pozzolan contents and high alkali content silica gel Na-zeolite + C-S-H + AFm/AFt Zeolite, e.g. natrolite Fly ash and clay C 0.8 SH y C 1.7 SH x CH C 3 A.CS.H 12 C 3 A.CC.H 12 C 3 A.3CS.H 32 gibsite C 3 A Portland cement

57 Global CO2 emission from cement production 10 9 tonne pa Improved kiln efficiency, use of bio fuels & natural gas ( t CO 2 ) 35% SCM for same concrete performance ( t CO 2 ) 1/5 Serie1 of RM CO Serie2 Serie3 2 recarbonated ( t CO 2 ) 2/5 of CO 2 emissions captured and stored ( t CO 2 ) 2/5 of CO 2 emissions captured and Serie4 stored (0.49 Serie t CO 2 ) Serie

58 CONCLUDING COMMENTS In order to achieve these reductions, the efforts must be global. In some areas CCS may be more economical than maximum use of SCMs or biofuels and visa versa. Alkali activated alumino-silicates can in theory replace up to 40% of Portland cement, but in regions where CCS is already required, would not provide additional CO 2 avoidance. Realistically these solutions can only take place within a global and transparent cap and trade system that does not distort competition.