Four main low-carbon technologies for cement production are presented, namely (a) alternative fuels (AF) for kiln, (b) renewable energy alternatives, (c) increasing cement replacement by fly ash and blast furnace slag and (d) Portland limestone cement.

1. LOW-CARBON TECHNOLOGIES
FOR CEMENT PRODUCTION
Dr J D BAPAT
Independent Professional
www.drjdbapat.com
Cement Business & Industry (CBI)
India 2015 Conference
3-4 September 2015, Mumbai, India

2. LOW-CARBON TECHNOLOGIES
FOR CEMENT
CHALLENGES: INDIAN CEMENINDUSTRY
 DEPLETING FOSSIL FUEL RESERVES
 SCARCITY OF RAW MATERIALS ESPECIALLY LS
 INCREASING DEMAND FOR CEMENT & CONCRETE
 GROWING ENVIRONMENTAL CONCERNS LINKED TO
CLIMATE CHANGE (.) 5% OF GLOBAL ANTHROPOGENIC
CARBON EMISSIONS
 CEMENT PRODUCTION CAPACITY ESTIMATED TO RISE
FROM CURRENT (2014) 366X106 t/a TO 550X106 t/a IN
2020
 WITH RISE IN PRODUCTION, CORRESPONDING INCREASE
IN INDUSTRY’S ABSOLUTE ENERGY USE & CO2
EMISSIONS
 IMPROVED PRODUCTION METHODS & FORMULATIONS
TO REDUCE CO2 EMISSIONS FROM CEMENT
MANUFACTURING PROCESS ARE HIGH ON AGENDA

3. LOW-CARBON TECHNOLOGIES FOR CEMENT
PROJECTED CEMENT INDUSTRY EMISSIONS
GLOBAL
billion tonnes/year
• CO2 emissions from 2010 2050
• Process 1.5 2.2
• Fuel & electricity 1.3 2.5
• Transport 0.1 0.2
________________________
• Total 2.9 4.9

4. LOW-CARBON TECHNOLOGIES FOR
CEMENT
ALTERNATIVE FUELS (AF) FOR KILN
 ALTERNATE FUELS (AF) FOR KILN HAVE NOT REALLY TAKEN
OFF IN INDIA
 PRESENT, THERMAL SUBSTITUTION RATE OR TSR: JUST
0.5-1% (.) DEVELOPED COUNTRIES TSR: 60%
 CMA IDENTIFIED HAZARDOUS WASTES FOR KILN BURNING:
REFUSE DERIVED FUEL (RDF) FROM MUNICIPAL SOLID
WASTE (MSW), USED TYRES, BIOMASS & PLASTIC WASTE
 PLANT TO INVEST FOR NECESSARY MODIFICATIONS IN
KILN SECTION (.) HENCE IMPORTANT CONSIDERATION:
LONG-TERM & SUSTAINED AVAILABILITY OF AF, NEAR
CEMENT PLANT
 FAVORABLE GOV. POLICY INITIATIVES REQUIRED

5. LOW-CARBON TECHNOLOGIES
FOR CEMENT
RENEWABLE ENERGY ALTERNATIVES
 FUTURE: SOLAR PV & WIND POWER HOLD PROMISE
 MODERN 1 MTPA CEMENT PLANT REQUIRES ABOUT 15 MW
INSTALLED CAPACITY OF ELECTRICAL ENERGY
 HIGHER RENEWABLE ENERGY RATES ACHIEVED IF OLDER,
SMALLER CAPACITY WIND TURBINES ARE REPLACED BY
MODERN HIGHER CAPACITY WIND TURBINES & ERECTING
SOLAR PV SYSTEMS ON THE SAME SITE. EXAMPLE: USED
MINES
 WIND & SOLAR POWER HAVE ADVANTAGE OF ‘BANKING’ &
‘WHEELING’: FEEDING POWER INTO THE NATIONAL
ELECTRICITY GRID AT ONE LOCATION (BANKING), TO USE IT
LATER AT DIFFERENT LOCATION (WHEELING)
 MAJOR REASON FOR VERY FEW SOLAR PV INSTALLATIONS IS
PRICE CONSTRAINT & REQUIREMENT OF LARGE AREA
 PRESENT SOLAR PV POWER IS NEARLY THREE TIMES COSTLIER
IN COMPARISON WITH COAL BASED POWER

6. LOW-CARBON TECHNOLOGIES FOR
CEMENT
INCREASING CEMENT REPLACEMENT BY
FA & BFS
 NEW GRINDING TECHNOLOGIES LEADING TO HIGHER
REPLACEMENT OF CEMENT BY FA & BFS IN BLENDED CEMENT,
WITH IMPROVED PERFORMANCE, SHOULD BE WELCOME
 INDIAN STANDARDS ALLOW MAX 35% FA & 70% BFS IN CEMENT
 HIGHER REPLACEMENT NOT COMPROMISING EARLY STRENGTH
DEVELOPMENT IS POSSIBLE THROUGH MECHANICAL ACTIVATION
 ENERGETICALLY MODIFIED CEMENT (EMC): ACTIVATION DONE
THROUGH SIZE REDUCTION IN VIBRATORY OR ATTRITION MILL
 MECHANICALLY ACTIVATED FA UPTO 65% & BFS UPTO 50-85%
 ELECTRICAL ENERGY FOR MECHANICAL ACTIVATION: 30-50 kWh/t
 VIEW IN COMPARISON WITH THERMAL & ELECTRICAL ENERGY
SAVINGS ACCRUED DUE TO HIGHER FA OR SLAG REPLACEMENT
 EMC CEMENT CO., NEAR JEWETT, TEXAS, USA, PRODUCES
CEMENT & POZZOLANA WITH COMMERCIALIZED TECHNOLOGY
BASED ON MECHANICAL ACTIVATION (.) PLANT STARTED IN SEPT.
2004, WITH CAPACITY: 1,50,000 t/a, CAN BE INCREASED TO MEET
DEMAND

7. LOW-CARBON TECHNOLOGIES
FOR CEMENT
PORTLAND LIMESTONE CEMENT (PLC)
 PLC: MODIFIED VERSION OF PC:IMPROVES ENVIRONMENTAL
FOOTPRINT & GIVES COMPARABLE PERFORMANCE
 IS269-2013: PERMITS ADDITION OF LS UP TO 5% AS
PERFORMANCE IMPROVER
 EUROPEAN STANDARD EN 197-1: 5% LS PERMITTED IN ALL
27 TYPES, AS MINOR ADDITIONAL CONSTITUENT (MAC)
 OUT OF THAT, 4 ARE PLC, PERMITTING HIGHER ADDITIONS
OF LS, IN ADDITION TO 5% AS MAC
 CEM II/A-L & CEM II/A-LL: 6-20% LS & CEM II/B-L &
CEM II/B-LL: 21-35% LS
 ASTM C595 & AASHTO M240: PLC MAY CONTAIN 5-15% LS

8. LOW-CARBON TECHNOLOGIES
FOR CEMENT
MANUFACTURING PLC
 CAN BE MANUFACTURED AT ANY PC MANUFACTURING PLANT
 CRUSHED & DRIED LS WEIGH-FED TO FINISH MILL ALONG WITH
CLINKER & GYPSUM
 LS, BEING SOFTER, IS MORE EASILY GROUND THAN HARDER
CLINKER & GETS CONCENTRATED IN FINE PARTICLE FRACTION
 OVERALL FINENESS MUST BE HIGH, FOR GOOD PERFORMANCE
 GRINDING TIME INCREASED TO BRING FINENESS OF CLINKER
SIMILAR TO OPC (.) HENCE PRODUCTION RATE IS SLOWED &
ADDITIONAL GRINDING ENERGY IS REQUIRED
 IT IS OFFSET BY LOWER CLINKER CONTENT & KILN FUEL
SAVINGS
 ADDITION OF GRINDING AIDS IMPROVES MILL PERFORMANCE
 GRINDING IMPROVES PARTICLE SIZE DISTRIBUTION &
HYDRATION ENHANCED BY PHYSICAL & CHEMICAL
INTERACTION

9. LOW-CARBON TECHNOLOGIES
FOR CEMENT
PORTLAND LIMESTONE CEMENT (PLC)
SUMMARY
 LS CEMENTS HAVE BEEN USED IN MANY COUNTRIES SINCE 1960’S & EU CEM II/A 6
TO 20% LS CEMENTS ARE THE LARGEST SINGLE TYPE OF CEMENT CURRENTLY
PRODUCED IN EUROPEAN COUNTRIES
 LS FINENESS & PARTICLE SIZE DISTRIBUTION ARE KEY PARAMETRS
ADVANTAGES:
 PLC RESULTS IN REDUCED GHG EMISSIONS
 WHEN PROPERLY OPTIMISED, PLC CONCRETE HAS FRESH PROPERTIES,
BLEEDING & STRENGTH SIMILAR TO OPC CONCRETE
 REDUCED PERMEABILITY
 SIMILAR CHLORIDE DURABILITY UP TO 15% REPLACEMENT
 SIMILAR CARBONATION RATE UP TO 15% REPLACEMENT, AT LOW w/c RATIO
 SUBSTANTIALLY IMPROVED SULPHATE RESISTANCE, WHEN PLC UP TO 15% LS, IS
BLENDED WITH SLAG WITH 50% REPLACEMENT
DISADVANTAGE:
 PERFORMANCE IS AFFECTED BY (A) QUALITY OF LS, (B) WHETHER INTERGROUND
OR BLENDED & (C) PARTICLE SIZE DISTRIBUTION

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