Present challenges for modern Cement Plants

Arturo Abarca, REFRAREFRAREFRAREFRATECHNIK México S.A. de C.V.

XXVII Technical Congress FICEM-APCAC

Agenda

• Energy-Efficiency

• CO2-Emissions

• Clinker

• Cement

• Summary / Discussion

source: vdz

source: vdz

Targets for Decrease in Energy Intensity, 2010-2050

(World Business Council for Sustainable Development)

3

3,1

3,2

3,3

3,4

3,5

3,6

3,7

3,8

3,9

4

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

3,9

3,2

3,6

3,4

Gj/Tonne

Change of circumstances for Cement Production (I)Change of circumstances for Cement Production (I)Change of circumstances for Cement Production (I)Change of circumstances for Cement Production (I)

• TodayTodayTodayToday

• 5 and more combustibles

• spot quantities possible

• peak-/off-peak-E-supply

• special E-net-rates for

atypical power consumption

• large variety of composite

cements

• emission trading

• CO2 monitoring

• 30 years before30 years before30 years before30 years before

• 100 % fuel or coal

• 1 fuel

• simple power supply

• 1 major product (CEM I)

• CO2 ?

1. Raw material related emissions:

clinker: 0,53 t CO2/ t clinker0,53 t CO2/ t clinker0,53 t CO2/ t clinker0,53 t CO2/ t clinker

cement: 0,40 t CO2/ t cement0,40 t CO2/ t cement0,40 t CO2/ t cement0,40 t CO2/ t cement

� Decarbonation of limestone

2. Fuel related emissions: 0,34 t CO2/ t cement0,34 t CO2/ t cement0,34 t CO2/ t cement0,34 t CO2/ t cement

� Combustion of fossil fuels

3. Energy related emissions from electricity consumption:

0,29 t CO2/ t cement0,29 t CO2/ t cement0,29 t CO2/ t cement0,29 t CO2/ t cement

� Grinding, cooling air etc.

COCOCOCO2222----emissions in the cement industry emissions in the cement industry emissions in the cement industry emissions in the cement industry

1,88

2,20

1,86

1,55

1,88

2,332,22

2,34

0,00

0,50

1,00

1,50

2,00

2,50

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055

Targets for CO2 total emissions, Gtonne 2010-2050

(World Business Council for Sustainable Development)

Baseline emissions

Blue emissions

Gtonne CO2

Cost optimization in the cement industry Cost optimization in the cement industry Cost optimization in the cement industry Cost optimization in the cement industry

Alternative Fuels Lower clinker content

+ lower costs

+/- process

- logistics

- investments

- surveillance

+ lower CO2 costs

- higher grade clinker

- logistics/storage

- investments ?

- quality control

- lower production costs ?

Change of circumstances for Cement ProductionChange of circumstances for Cement ProductionChange of circumstances for Cement ProductionChange of circumstances for Cement Production

• TodayTodayTodayToday

• large variety of composite

cements

• HPC also with composite cements

• 42,5 R and 52,5 R

• extreme fine grinding

• combo grinding

• high performing Clinkers required

• 30 years before30 years before30 years before30 years before

• 1 major product (CEM I)

Higher fineness:

CEM II/A-S (15 – 20 % S) + 200 to 500 Blaine

CEM II/A-V (15 - 20 % V) + 800 to 1000 Blaine

CEM II/A-LL (15 - 20 % LL) +1000 to 1200 Blaine

Activating grinding aids:

Possible gain of early strength 2 – 4 N/mm² (after 1 or 2 d)

Early strength Early strength Early strength Early strength

Grindability of different main constituents acc. Zeisel

for 4000 Blaine

Clinker 40 – 60 kWh/t

Fly ash > 45 µm 20 – 30 kWh/t

Limestone 5 – 15 kWh/t

Slag 50 – 80 kWh/t

Composite Cements Composite Cements Composite Cements Composite Cements

70%

71%

72%

73%

74%

75%

76%

77%

78%

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055

Targets for cement to clinker ratio, 2010-2050

(World Business Council for Sustainable Development)

71%71%71%71%

73%73%73%73%

74%74%74%74%

77%77%77%77%

Clinker %

Alternative FuelsAlternative FuelsAlternative FuelsAlternative Fuels

Targets for alternative fuels use, 2010-2050

(World Business Council for Sustainable Development)

0%

10%

20%

30%

40%

50%

60%

70%

80%

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055

5%5%5%5%

12%12%12%12%

23%23%23%23%

37%37%37%37%

% AF

Alternative fuel utilization in German cement plants

4,1

7,410,2 10,8

13,415,8

18,6

23

38,4

42,1

47,650

52,554,4

30,3

34,9

25,7

0

10

20

30

40

50

60

1987

1994

1996

1998

2000

2002

2004

2006

2008

Subst

itutionsr

ate

in %

Subst

itutionsr

ate

in %

Subst

itutionsr

ate

in %

Subst

itutionsr

ate

in %

Source: VDZ

37%

Target Target Target Target forforforfor 2050205020502050

(WBCSD)(WBCSD)(WBCSD)(WBCSD)

PetcokePetcokePetcokePetcoke an an an an ““““AlternativAlternativAlternativAlternativ fuelfuelfuelfuel””””

Secondary fuel from oil refinery coker units

“Petroleum coke” or “Petcoke”High Carbon content

High calorific value (~ 30GJ/t)

Low volatiles (<11%)Low ash content

Very low ash content <1%

High Sulfur content

2-6% (price strongly depending on the S-content)

Going from coal to petcoke: What changes ?Going from coal to petcoke: What changes ?Going from coal to petcoke: What changes ?Going from coal to petcoke: What changes ?

Raw coal

Uniform blending petcoke/raw coal (if petcoke < 100%)Coal mill

Requires higher fineness (due to less volatiles)

Affects mill capacity (different grindability and higher fineness, evaluate by trial)Kiln

Low ash and high CV

Low reactive fuel, ignition delayed

High sulfur causing more plugging (kiln inlet/preheater)

Stable and controlled kiln process to minimize sulfur cyclesClinker quality

More SO3 in clinker (better strength development, red. gypsum addition)

Rules: Basic potential & supplyRules: Basic potential & supplyRules: Basic potential & supplyRules: Basic potential & supply

Alkali/sulfur

For a first conservative approach, go for following total inputs :

On precalciner kilns even better result are achievable , under ideal conditions :

Petcoke supply

Top grade (2%S, HGI>55)

High grade (4%S, HGI>55)

Low grade (6/7% S, HGI 40)

SO3

inputs < 1.5 % (clinker basis)

Molar A/S > 0.8

SO3

inputs < 2.5 %

Molar A/S down to 0.4

PetcokePetcokePetcokePetcoke : Mixing & Grinding: Mixing & Grinding: Mixing & Grinding: Mixing & Grinding

Raw coal/petcoke preparation

Controlled mixing from two feed hoppers

Coal mill

Recommended fineness for 100 % petcoke

Determine mill output by trial (HGI can be misleading)

depending on the “shot”-amount

R 90 µ < 5 %

R 200 µ < 1%

Inside the KilnInside the KilnInside the KilnInside the Kiln

Curcuits inside rotary kilns

Hot meal Hot meal Hot meal Hot meal –––– Indication of process stabilityIndication of process stabilityIndication of process stabilityIndication of process stability

Hot meal analysis

Adequate frequency, usually once per shift

Monitor LOI (decarbonation), SO3, K

2O

SO3< 5 % (if chlorine < 0.5%)

Risk of coating due to SO3 and Cl concentration in hot meal

PreheaterPreheaterPreheaterPreheater carecarecarecare

Preheater cleaning

Add poking possibilities and air cannons (can be up to 100) where coatings occur

Removing of heavy blockages can also be done with CARDOX blasting on demand.

Anti coating SiC-refractories in the riser duct

Observation of the Temperature-profile inside the inlet/rising duct

Clinker chemistryClinker chemistryClinker chemistryClinker chemistry

Alkalisulfate on AlitAlkalisulfate on Alit

Clinker chemistryClinker chemistryClinker chemistryClinker chemistry

• K2SO4 has a melting point at 1069°C

• evaporation/condensation-circuits will develop

• low alkali/sulfate ratio may have an impact on setting

• high alkali/sulfate ratio ⇒ K2SO4

- High solubility in water

- much quicker than Hemihydrates or Anhydrite

- may help the workability

• K2SO4 has a melting point at 1069°C

• evaporation/condensation-circuits will develop

• low alkali/sulfate ratio may have an impact on setting

• high alkali/sulfate ratio ⇒ K2SO4

- High solubility in water

- much quicker than Hemihydrates or Anhydrite

- may help the workability

Sulfates Chlorides Alkalis

(sulfides)

Basic bricks reaction infiltration infiltration, reaction

(C2S, C3MS2, CMS, KFeS2) (KFeS2)

Alumina bricks reaction infiltration reaction

(C4A3·SO3) (KAS4, KAS6)

Castables reaction infiltration reaction

(C4A3·SO3 ) (KAS4, KAS6)

Kiln shell, reaction catalytic reaction reaction

Metallic anchors (NiS, Cr2S3) (chromate formation)

Reaction of Volatile Elements with Refractory MaterialsReaction of Volatile Elements with Refractory MaterialsReaction of Volatile Elements with Refractory MaterialsReaction of Volatile Elements with Refractory Materials

Oxidizing Atmosphere

2 C2S + MgO +SO3 CaSO4 + C3MS2

C3MS2 + MgO +SO3 CaSO4 + 2 CMS

CMS + MgO +SO3 CaSO4 + M2S

2 CaSO4 + K2SO4 2 CaSO4.K2SO4

3 MgO.Al2O

3+ 4 CaO + SO3 4CaO.3Al

2O

3.SO

3+ 3 MgO

Essential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with Basic Brick Compoundsasic Brick Compoundsasic Brick Compoundsasic Brick Compounds

Reducing Atmosphere

4 MgO + 2 K2O + 4 FeO.Al

2O

3+ 8 SO

24 KFeS

2+ 4 MgO.Al

2O

3+ 11 O

2

MgFe2O

4+ K

2O + 4 SO

22 KFeS

2+ MgO + 6 O

2red. (1)

2 KFeS2+ 8 O2 K2SO4 + Fe2(SO4)3 ox. (2)

PbO + SO3 PbS + 2 O2

2 CO CO2 + C (Boudouard’s equilibrium)

Essential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with BEssential Chemical Reactions of Kiln Atmosphere Compounds with Basic Brick Compoundsasic Brick Compoundsasic Brick Compoundsasic Brick Compounds

A3S2 + 16 SiO2 +3 K2O 3 KAS6 (feldspar formation)

A3S2 + 10 SiO2 +3 K2O 3 KAS4 (leucite formation)

2 A3S2 + 8 SiO2 +6 K2O 6 KAS2 (kalsilite formation)

11 Al2O3 + K2O + Na2O (K,N)A11 (ß-corundum formation)

K2SO4.2CaSO4 + H2O CaSO4.K2SO4.H2O (syngenite formation)

2 CaSO4 + K2SO4 2CaSO4.K2SO4

Essential Chemical Essential Chemical Essential Chemical Essential Chemical ReactionsReactionsReactionsReactions of of of of KilnKilnKilnKiln AtmosphereAtmosphereAtmosphereAtmosphere CompoundsCompoundsCompoundsCompounds

withwithwithwith AluminaAluminaAluminaAlumina BrickBrickBrickBrick CompoundsCompoundsCompoundsCompounds

hot face

cold face

Corrosion by sulfates

Infiltration and condensationof chlorides

Crack formation due to elasticity differences

SpallingSpallingSpallingSpalling of a basic brick caused by elasticity differencesof a basic brick caused by elasticity differencesof a basic brick caused by elasticity differencesof a basic brick caused by elasticity differences

due to infiltrationsdue to infiltrationsdue to infiltrationsdue to infiltrations

Conflicting goals?

Reduction in the clinker to cement ratio

Lower clinker burnability

Higher quality clinker

CO2 reduction

Reduction in

energy intensity

Changes in clinker chemistry

Higher C3S content

Higher energy consumption for clinker

production

CONFLIC

T

Use of

fluxing

agents?

POSIBLE MEASURES TO REACH GOAL

Conflicting goals?

Reduction in the clinker to cement ratio

Lower clinker burnability

Higher quality clinker

CO2 reduction

Reduction in

energy intensity

Changes in clinker chemistry

Higher C3S content

Higher energy consumption for clinker

production

CONFLIC

T

Use of

fluxing

agents?

POSIBLE MEASURES TO REACH GOAL

Conflicting goals?

Reduction in the clinker to cement ratio

CO2 reduction

Reduction in

energy intensityCONFLIC

T

POSIBLE MEASURES TO REACH GOAL

Finer Grinding

Increased energy consuption in cement grinding

Increased wear of grinding media

Wherever in the world you are, the road ahead is full of new

challenges.

Refratechnik is there, to help you meet

these challenges!

But you are not alone

Thank you very much for your kind attention