Evaluation of a calcium looping CO2capture plant retrofit to a coal-fired power plant

Dawid Hanak, Chechet Biliyok, Edward Anthony, Vasilije Manovic

Combustion and CCS Centre, Cranfield University

d.p.hanak@cranfield.ac.uk

Battersea Power Plant image by mendhak (http://bit.ly/1CktEqq)

Outline

1. Background

2. Process model description and assumptions

3. Comparison of retrofit scenarios

4. Performance evaluation

5. Conclusions

1

Outline

1. Background

2. Process model description and assumptions

3. Comparison of retrofit scenarios

4. Performance evaluation

5. Conclusions

1

Background

Figure 1: Cumulative CO2 emission reduction share of key measures for meeting the 2DS

Nuclear8%

Power generation

efficiency and fuel switching

3%

Renewables21%

End-use fuel switching

12%

CCS14%

End-use fuel and electricity

efficiency42%

2IEA (2013), Tracking Clean Energy Progress 2013. IEA Input to the Clean Energy Ministerial, IEA Publications, Paris, France.

Background

3

Amine

scrubbing

(MEA)

Oxy-combustion

Chilled ammonia

process

(CAP)

Calcium looping

process

(CaL)

Technology maturity level

(1 – concept,

9 – operating)

8 7 6 – 7 6

Efficiency penalty (%

points)

9.5 – 12.5 8 – 12 4 – 9 5 – 8

Ability for multi-component

capture

No N/A Yes Yes

Other advantages over

amine scrubbing

• Nearly pure CO2

stream

• Availability at

lower price

• Higher

absorption

capacity

• Increase in the

electric output

• High CO2

uptake

• Low sorbent

cost

Table 1: Comparison of different CO2 capture technologies

Hanak, D.P., Anthony, E.J. and Manovic, V. (2015), Energy and Environmental Science, 8, pp. 2199-2249

Outline

1. Background

2. Process model description and assumptions

3. Comparison of retrofit scenarios

4. Performance evaluation

5. Conclusions

4

Process modelling

To compare different retrofit scenarios, the following models has been built in

Aspen Plus®:

• A 580 MWel supercritical coal-fired power plant model;

• Calcium looping CO2 capture plant model;

• Amine scrubbing CO2 capture plant model;

• Chilled ammonia scrubbing CO2 capture plant model;

• CO2 compression unit model;

• Cryogenic air separation unit model.

5

Hanak, D.P., Biliyok, C., Anthony E.J. and Manovic, V. (2015), International Journal of Greenhouse Gas Control, 42, pp.226-236

Hanak, D.P., Biliyok, C. and Manovic, V. (2015), Applied Energy, 151, pp. 258-272

Hanak, D.P., Biliyok, C. and Manovic, V. (2015), International Journal of Greenhouse Gas Control, 34, pp. 52-62

Hanak, D.P., Biliyok, C., Yeung, H. and Białecki, R. (2014), Fuel, 134, pp. 126-139

Calcium looping model assumptions

Carbonator model assumptions:

• Average conversion model by Rodríguez et al. (2010);

• CO2 equilibrium partial pressure by Baker (1968).

Calciner model assumptions

• Chemical and phase equilibrium (Gibbs free energy minimisation);

• Incomplete calcination;

• Heat for sorbent calcination provided through oxy-combustion of fuel;

• Incomplete fuel combustion.

6Rodríguez N., Alonso M., Abanades J. C. (2010), Chemical Engineering Journal,156 pp. 388-394

Baker E.H. (1962), Journal of the Chemical Society, pp. 464–70.

Calcium looping model assumptions

Table 2: Full-scale calcium looping process operating conditions

7

Parameter Value

Carbonator temperature (°C) 650

Calciner temperature (°C) 900

Fluidising fan pressure increase (mbar) 150

Excess oxygen (%vol) 2.5

Initial fresh limestone to sorbent looping rate ratio (-) 0.05

Live steam pressure (bar) 242.3

Reheated steam pressure (bar) 45.2

IP/LP crossover pressure (bar) 9.3

Condenser pressure (bar) 0.069

Live and reheated steam temperature (°C) 593.3

Mechanical efficiency of the rotational machinery (%) 99.6

Outline

1. Background

2. Process model description and assumptions

3. Comparison of retrofit scenarios

4. Performance evaluation

5. Conclusions

8

Solvent scrubbing retrofit configuration

9Figure 2: 580 MWel Supercritical CFPP retrofit with chemical solvent scrubbing for CO2 capture

Retrofit includes the following interface

points:

I) Flue gas ducts

II) Solvent pumps electrical connections

III) Chilling system electrical connections

IV) CO2 compressors electrical connections

V) Steam extraction tie-in

Alternative integration strategies

10Figure 3: Alternative integration configuration

Calcium looping retrofit configuration

11Figure 4: Supercritical CFPP retrofit with calcium looping process for CO2 capture

Outline

1. Background

2. Process model description and assumptions

3. Comparison of retrofit scenarios

4. Performance evaluation

5. Conclusions

12

Calcium looping retrofit

13Figure 5: Key parametric study results for the CFPP retrofitted with the calcium looping process

28%

29%

30%

31%

32%

0.0

2

0.0

3

0.0

4

0.0

5

0.0

6

0.0

7

0.0

8

0.0

9

0.1

0

20%

30%

40%

50%

60%

70%

80%

90%

95%

1.5

%

2.0

%

2.5

%

3.0

%

3.5

%

4.0

%

4.5

%

70%

75%

80%

85%

90%

Relative make-up rate(-)

Oxygen content(%vol,wet)

Oxygen excess(%vol,dry)

CO₂ capture level (%)

Ne

t th

erm

al e

ffic

ien

cy (

%H

HV)

Coal Coal/Biomass (80/20) Natural gas

Comparison of different technologies

14Figure 6: Performance comparison

0

200

400

600

800

1000

1200

CaL(C)

CaL(C/B)

CaL(NG)

MEA CAP

Gro

ss

po

we

r o

utp

ut

(MW

el)

Net power plant output Air separation unit CompressionSecondary steam cycle auxiliares Power plant auxiliaries Fluidizing fansChillers Pumps and fans Steam extraction

Comparison of different technologies

15

Table 3: Comparison of investigated retrofit scenarios

Parameter Reference

CFPP

Amine

scrubbing

Chilled

ammonia

scrubbing

Calcium looping

Coal Coal

and

Biomass

Natural

gas

System performance indicators

Net electricity production (MWel) 552.7 416.2 424.1 799.9 768.4 849.4

Net thermal efficiency (%HHV) 38.5 29.0 29.5 30.6 30.8 31.8

Integration impact indicators

Total CO2 capture level (-) - 0.900 0.900 0.900 0.900 0.900

Carbonator/absorber capture level (-) 0.900 0.900 0.796 0.711 0.834

Change in the net power output (MWel) - -136.5 -128.6 247.2 215.7 296.8

Net efficiency penalty (% points) - 9.5 9.0 7.9 7.7 6.7

Increase in net specific chemical energy

consumption (%)

- 32.8 30.3 25.6 25.1 21.0

Hanak, D.P., Biliyok, C., Anthony E.J. and Manovic, V. (2015), International Journal of Greenhouse Gas Control, 42, pp.226-236

Conclusions

16

• CaL retrofit scenario was fund less complex compared to chemical solvent scrubbing.

• CaL efficiency penalty of 6.7–7.9%HHV (9.0–9.5%HHV points for chemical solvent scrubbing).

• CaL retrofit led to 50–60% increase in the net power output.

• Further techno-economic evaluation of the retrofit scenarios is required.