Technical and Economic Evaluation of Ca-looping Process ...

CaReCI Project Seminar: “Sustainable and efficient carbon capture for the cement industry”

October 8, 2019

Technical and Economic Evaluation of Ca-looping Process for CO2 Capture in the Cement Industry

Diogo Santos, Rui Filipe, Miguel A. Torres, Henrique A. Matos


Objectives and Guidelines

1. Model Integration of calcium looping-cycle technology with Cement plant for CO2 capture (via ASPEN PLUS V9);

2. Design of heat exchanger networks (via ASPEN ENERGY ANALYZER V9);

3. Techno-economic feasibility assessment of design alternatives;

Process Scheme 1. CO2 capture efficiency is assessed by means of the

detailed carbonator model (gProms, Excel);

2. Calcination efficiency was assumed to be complete as predicted by models when calciner is operated under similar conditions [Ylätalo et al., 2012; Martínez et al., 2013];

3. CaL integration analysis, mass and energy balances have been calculated by Aspen Plus;

2


CaL Process Scheme – Carbonator/Calciner

3

Important Parameters• Specific make-up flow rate F0/FCO2

• Specific recycle flow-rate FR,Ca/FCO2

• Sorbent inventory

O2 or Air ?

Adapted from Romano, 2013. [1]

QinQout

Aspen Plus


Process Scheme – Steam cycle

• Carbonator

• Calciner

• Steam cycle

• Compression train

Main SectionsSteam Cycle [2]

Parameter Value

Live steam temperature, ºC 600

Live steam pressure, bar 290

Reheat steam temperature, ºC 600

Reheat steam pressure, bar 48.5

Deaerator pressure, bar 7

Condensing pressure, bar 0.1

Feedwater pumps mechanical/electric efficiency, %

90

4


Process Scheme – Compression Train

• Carbonator

• Calciner

• Steam cycle

• Compression train

Main Sections

5

CO2 compression train [2]

Parameter Value

Intercooling temperature, ◦C 60

Compressors isentropic efficiency, % 85

Pressure ratio 3.3

Final CO2 pressure, bar 120

Final CO2 temperature, ºC 90


Cryogenic Air Separation Unit (ASU)

Oxyfuel Process

6

Oxyfuel combustion• Oxy-combustion of coal within the calciner (internal combustion);• The idea is use highly pure oxygen as oxidant, diluted with a portion

of recycled combustion gases to control the combustion temperature;• The high purity oxygen used for combustion is produced in a

cryogenic ASU;


Process Alternatives using Air as oxidant

• Internal combustion (IC):100% internal combustion would result in a low final CO2 concentration;Internal combustion is necessary to ensure fluidization;

7

• External combustion (EC):Heating of solids entering in the calciner;Recirculation of the external combustion gases to the carbonator;


Carbonator Model based on the microscale particle model

Sensitivity analysis has been carried out by varying the primary input parameters of the model:➢ Make-up and purge flows: an increase in the variable F0/FCO2 results in a in a higher sorbent average

activity along with lower amounts of coal ash and CaSO4. ➢ Solid recycle flow: an increase in FR/FCO2 leads to lower sorbent average conversions and higher kinetics

in the carbonator. This also results a heat increased input in the calciner needed to heat the recycled solids up at calcination temperature.

The effect of ash and sulfur is relevant and require higher make-up, recycles and inventories to reach the same capture efficiency.

ECO2 (FR, F0, Fash, FS)

8

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

10 12 14 16 18 20%

ECO

2

FR/FCO2

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

Polinomial (0.09)

CO2 capture efficiency in the carbonator vs. FR/FCO2, for Fash/FCO2=0.01309, FS/FCO2=0.00719.

FO/FCO2


Final equation:ECO2 = A * (FR/FCO2)2 + B * (FR/FCO2) + C

A = D* (F0/FCO2)4 + E* (F0/FCO2)3 + F * (F0/FCO2)2 + G*(F0/FCO2) + H

D = P * (Fash/FCO2) + QP = AQ * (Fs/FCO2)+ ARQ = AS * (Fs/FCO2) + AT

E = R * (Fash/FCO2) + SR = AU * (Fs/FCO2) + AVS = AX * (Fs/FCO2) + AZ

F = T * (Fash/FCO2) + UT = BA * (Fs/FCO2) + BBU = BC * (Fs/FCO2) + BD

G = V * (Fash/FCO2) + XV = BE * (Fs/FCO2) + BFX = BG * (Fs/FCO2) + BH

H = Z * (Fash/FCO2) + AAZ = BI * (Fs/FCO2) + BJAA = BK * (Fs/FCO2) + BL

B = I* (F0/FCO2)4 + J* (F0/FCO2)3 + K * (F0/FCO2)2 +L* (F0/FCO2) + M

I = AB * (Fash/FCO2) + ACAB = BM *(Fs/FCO2)+ BNAC = BO * (Fs/FCO2) + BP

J = AD * (Fash/FCO2) + AEAD = BQ * (Fs/FCO2)+ BRAE = BS * (Fs/FCO2) + BT

K = AF * (Fash/FCO2) + AGAF = BU * (Fs/FCO2) + BVAG = BX * (Fs/FCO2) + BZ

L = AI * (Fash/FCO2) + AJAI = CA * (Fs/FCO2) + CBAJ = CC * (Fs/FCO2) + CD

M = AK * (Fash/FCO2) + ALAK = CE * (Fs/FCO2) + CFAL = CG * (Fs/FCO2) + CH

C = N *(F0/FCO2)+ ON = AM * (Fash/FCO2) + AN

AM = CI * (Fs/FCO2) + CJAN = CK * (Fs/FCO2) + CL

O = AO * (Fash/FCO2) + APAO = CM *(Fs/FCO2)+ CNAP = CO *(Fs/FCO2) + CP

Aspen Plus

Primary Input ParametersMake-up (F0/FCO2)

Solid recycle flow (FR/FCO2)

F0/FCO2 = ?FR/FCO2 = 10

CO2 capture efficiency, %

90

9

Carbonator Model (to calculate fresh CaCO3 make-up)

gPROMS/Excel


Configuration Air 100%IC

Flue gas

3279 kmol/h

Coal Combustion

2954 kmol/h

Calci. (Make-up)

230 kmol/h

To ambient

328 kmol/h

Compression train

43 kmol/h

To storage

6092 kmol/h

ConfigurationOxyfuel

Flue gas

3279 kmol/h

Coal Combustion

2019 kmol/h

Calcination (Make-up)

230 kmol/h

To ambient

328 kmol/h

Compression train

57 kmol/h

To storage

5143 kmol/h

CO2 molar balance

Name of the configuration Oxyfuel Air 100%IC

Air 10%IC

Air 5%IC

FR/FCO210 10 10 10

F0/FCO20.0705 0.0705 0.0824 0.0834

CO2 mass flow rate from flue gas, kg/s 40 40 40 40

Coal input, kg/s 9.6 14 29.7 32.6

CO2 mass flow rate from coal combustion, kg/s 24.7 36.1 72.4 79.6

CO2 mass flow rate to storage, kg/s 63 75 110 117

CO2 mass flow rate release to ambient, kg/s 4.0 4.0 10.5 11.6

CO2 final composition, %molar 95% 27% 73% 84%

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ConfigurationAir 5%IC

Flue gas

3279 kmol/h

Coal Combustion

6514 kmol/h

Calcination (Make-up)

782 kmol/h

To ambient

946.57 kmol/h

Compression train

27 kmol/h

To storage

9602 kmol/h


Name of the configuration

Air 100%IC

Oxyfuel Air 5%IC

Air 10%IC

Input Parameters

FR/FCO2 10 10 10 10

F0/FCO2 0.0705 0.0705 0.0834 0.0824

CO2 final, %molar 27% 95% 84% 73%

Coal input, kg/s 14.0 9.6 32.6 29.7

Coal thermal input, MWLHV

432 295 1004 913

Ca-looping Process – Electric Power balance

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Name of the configuration Air 100%IC

Oxyfuel Air 5%IC

Air 10%IC

Electric power balance, MW

Steam turbines 133 133 384 349

Condensate extraction pump -0.06 -0.06 -0.18 -0.16

Boiler feedwater pump -2.9 -2.9 -8.4 -7.6

Flue gas blower -3.2 -3.2 -3.2 -3.2

Coal handling -0.42 -0.29 -0.98 -0.89

Limestone handling -0.58 -0.58 -1.97 -1.77

Ash handling -0.12 -0.08 -0.28 -0.26

Condenser auxiliaries -1.5 -1.5 -4.2 -3.8

CO2 compression -113 -28 -57 -62

Air Separation Unit - -4.36 - -

Net electric plant output : 11 92 307 269


Cement Plant

Oxyfuel Air 100% IC Air 10% IC Air 5% IC

Direct fuel consumption (qclk), MJLHV/kgclk 𝑞𝑐𝑙𝑘 =𝑚𝑓𝑢𝑒𝑙 ∗ 𝐿𝐻𝑉𝑓𝑢𝑒𝑙

𝑚𝑐𝑙𝑘3.7 10 13 22 24

Direct CO2 emission (eclk), kgCO2/tonclk𝑒𝑐𝑙𝑘 =

𝑚𝐶𝑂2

𝑚𝑐𝑙𝑘818 82 82 215 236

Net electricity consumption (Pel,clk), kWhe/tonclk 𝑃𝑒𝑙,𝑐𝑙𝑘 =𝑃𝑒𝑙𝑚𝑐𝑙𝑘

108 -412 45 -1418 -1635

EU-28 non-CHP energy mix (2015) (𝜼𝒆𝒍 = 𝟒𝟓. 𝟗%, 𝒆𝒆𝒍 = 𝟐𝟔𝟐 𝒌𝒈𝑪𝑶𝟐/𝑴𝑾𝒉𝒆)

Indirect fuel consumption (qel,clk), MJLHV/kgclk 𝑞𝑒𝑙,𝑐𝑙𝑘 =𝑃𝑒𝑙,𝑐𝑙𝑘η𝑒𝑙

0.85 -3.2 0.35 -11 -13

Equivalent fuel consumption (qclk, eq), MJLHV/kgclk𝑞𝑐𝑙𝑘,𝑒𝑞 = 𝑞𝑐𝑙𝑘 + 𝑞𝑒𝑙,𝑐𝑙𝑘 4.5 6.5 12.8 11.2 11.3

Indirect CO2 emission (eel,clk), kgCO2/tonclk𝑒𝑒𝑙,𝑐𝑙𝑘 = 𝑃𝑒𝑙,𝑐𝑙𝑘 ∗ 𝑒𝑒𝑙 28 -108 12 -371 -428

Equivalent CO2 emission (eclk,eq), kgCO2/tonclk𝑒𝑐𝑙𝑘,𝑒𝑞 = 𝑒𝑐𝑙𝑘 + 𝑒𝑒𝑙,𝑐𝑙𝑘 846 -26 94 -157 -192

Equivalent fuel consumption increase, %𝑞𝑐𝑙𝑘,𝑒𝑞−𝑞𝑐𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓

𝑞𝑐𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓- 44% 185% 148% 152%

Equivalent CO2 emission reduction, %𝑒𝑐𝑙𝑘,𝑒𝑞−𝑒𝑐𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓

𝑒𝑐𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓- -103% -89% -119% -123%

SPECCA*, MJLHV/kgCO2𝑆𝑃𝐸𝐶𝐶𝐴 =

𝑞𝐶𝑙𝑘,𝑒𝑞 − 𝑞𝐶𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓

𝑒𝐶𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓 − 𝑒𝐶𝑙𝑘,𝑒𝑞- 2.2 11 6.7 6.6

Carbon Capture Ratio, % 𝐶𝐶𝑅 =𝑚𝐶𝑂2,𝑐𝑎𝑝𝑡

𝑚𝐶𝑂2,𝑔𝑒𝑛- 97% 98% 98% 98%

* The SPECCA index quantify the increased equivalent fuel consumption to avoid the emission of CO2 in a cement kiln with CO2 capture with respect to a reference cement kiln without capture.

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KPI’s : Cement Plant + CaL capture facility


Process Heat Integration of CaL -Design of HEN

0100200300400500600700800900

[ºC]

CO2 to compressionSurplus heat CR

Gas flow leaving CR

Reheating steam

HRSG steam

Preheating steam

CO2 after 1st compression

CO2 after 2nd compression

CO2 after 3rd compression

CO2 after 4th compression

Condensed steam

O2 entering CL

Thickoff rule priority (TRP) (Lara, 2013)• The main idea is to pair the cold streams (CS)

with the highest objective temperature and the hot streams (HS) with highest temperature;

• When several streams are available for pairing, this case prioritizes the matching of those streams that can be exhausted in just one heat exchange;

• If the amount of energy required for the CS could be satisfied with several HS, the CS was split.

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Global system streams - Oxyfuel configuration

CR - CarbonatorCL - Calciner


Process Heat Integration - Design of Heat Exchanger Networks

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Total Utilities w/o Heat Integration(Oxyfuel configuration)

770 MW

Aspen Energy Analyzer

TRP Total Utilities15 MW

Energy Savings98%

Oxyfuel Air 100% IC Air 10% IC Air 5% IC

Utilities w/o Heat Integration, MW

770 1091 1686 1835

Utilities Heat Integration, MW

15 221 15.4 35

Energy Savings, % 98 80 99 98


Economic Analysis- main assumptions

Main Financial Assumptions

Capacity factor, % 91.3

Tax rate, % 0

Operational life, years 25

Construction time for CO2 capture plant, years

3

Percentage of TPC depreciated, % 100

Inflation rate, % 0

Discount rate, % 8

Annual working hours 8000

Annual Production ca (kton) 1500

CAPEX

Indirect costs factor (INCF), %TDC 14

Owner´s costs factor (OCF), %TDC 7

Project contingencies factor (CFproject) 15

Variable OPEX

Raw material price, €/t 3

Coal, €/GJLHV 3

Electricity, €/MWhe 58.1

Cooling water, €/m3 0.39

Carbon tax, €/tCO2 8

Fixed OPEX

Insurance and local tax, %TPC/year 2

Maintenance cost, %TPC/year 2.5

Number of employees in cement kiln 100

Number of employees in CO2 capture plant 120

Cost of labor, k€/y per person 60

Maintenance labor, % of maintenance cost 40

Administrative and support labor, % O&M labor cost

30

Once Capex and OPEX have been defined, the cost of clinker (COC) are calculated as the breakeven selling price leading to a net

present value (NPV) of the project equal to 0.

COC = annualized CAPEX (Ccap) + fuel cost (Cfuel) + raw material cost (CRM) + electricity cost (Cel)

+ operating and maintenance cost (CO&M) + carbon tax (CCtax)

𝑪𝑨𝑪 =𝐶𝑂𝐶 − 𝐶𝑂𝐶𝑟𝑒𝑓

𝑒𝑐𝑙𝑘,𝑒𝑞,𝑟𝑒𝑓 − 𝑒𝑐𝑙𝑘,𝑒𝑞

The cost of CO2 avoided (CAC) is evaluated based on the cost of clinker and the equivalentspecific emissions of the cement plant with and without CO2 capture.

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Economic Analysis - main results

Cement Plant

Oxyfuel Air 100% IC

Air 10% IC

Air 5% IC

TPC, cement plant + CO2

capture plant (M€)

214 590 568 959 820

TPC, CO2 capture plant (M€)

- 376 354 745 606

Annual OPEX (M€)

67 61 117 54 41

COC (€/tclk) 58 82 116 104 85

Cost of CO2

avoided (€/tCO2)- 35 85 54 35

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-150

-100

-50

0

50

100

150

200

Reference cementplant

Oxyfuel Air Air - 10 % InternalCombustion

Air - 5 % InternalCombustion

Co

st o

f cl

inke

r (€

/tcl

k)

CAPEX Fixed operating costs

Other variable cost Raw material

Coal Electricity consumption/generation

Total cost of clinker


Economic Analysis - main results

Cement Plant

Oxyfuel Air 100% IC

Air 10% IC

Air 5% IC

TPC, cement plant + CO2 capture plant (M€)

214 590 568 959 820

TPC, CO2 capture plant (M€)

- 376 354 745 606

Annual OPEX (M€) 67 61 117 54 41

COC (€/tclk) 58 82 116 104 85

Cost of CO2 avoided (€/tCO2)

- 35 85 54 35

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-150

-100

-50

0

50

100

150

200

Oxyfuel Air Air - 10 % InternalCombustion

Air - 5 % InternalCombustion

Co

st o

f C

O2

avo

ided

(€

/tC

O2)

CAPEX Fixed operating costs

Other variable cost Raw material

Coal Electricity consumption/generation

Total cost of CO2 avoided


Economic Analysis – Sensitivity Analysis

CAPEX of CO2 capture technologies: +35 / - 15%

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0

20

40

60

80

100

120

1 2 3 4 5

Co

st o

f C

O2

avo

ided

(€

/tC

O2)

Coal price (€/GJLHV)

Oxyfuel

Air

Air - 10% InternalCombustion


0

20

40

60

80

100

120

-20 0 20 40

Co

st o

f C

O2

avo

ided

(€

/tC

O2)

Change in CAPEX (%)

Oxyfuel

Air



Coal price: +/- 50% of the reference cost


Economic Analysis – Sensitivity Analysis

Carbon tax: 0-100 €/tCO2

19

-40

-20

0

20

40

60

80

100

120

25 35 45 55 65 75 85 95Co

st o

f C

O2

avo

ided

(€

/tC

O2)

Electricity price (€/MWh)

Oxyfuel

Air



0

20

40

60

80

100

120

0 50 100

Co

st o

f cl

inke

r (€

/tce

men

t)

Carbon tax (€/tCO2)

w/o CCS

Oxyfuel

Air



Electricity price: +/- 50% of the reference cost


Main Conclusions

• CaL process was modelled using the Aspen Plus including the information from the detailed particle model

for the Carbonator

• 100 % Internal Combustion (IC) using air as oxidant is unpracticable

• Heat integration is an important achievement with global reduction of 98-99% of the initial requested

Thermal utilities.

• For all alternatives, a very high Carbon Capture Ratio, near 99%

• Oxyfuel coal combustion is well compared with the use of coal 5% IC in terms of:

• Final CO2 stream concentration, 95 % and 84 % ;

• COC – Cost of Clinker as breakeven selling price for a NPV=0 @ 25 years is 82 and 85 €/ton;

• CAC- Cost of CO2 avoided (35 €/ton) equal for both ;


Thanks for your attention !

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Technical and Economic Evaluation of Ca-looping Process ...

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