Postcombustion capture with CaO: experimental results from the 1.7 MWth pilot facility of la Pereda

B. Arias1, M.E. Diego1, J.C. Abanades*1L. Diaz2, M. Lorenzo2, J Alvarez3, D. Martínez3, A. Sánchez‐Biezma4

1Spanish Research Council (CSIC‐INCAR), Oviedo, Spain.2 HUNOSA, Oviedo, Spain

3 Foster Wheeler Energía S.L.U.,  Madrid, Spain.4 Endesa Generación, Madrid, Spain.

5th High Temperature Solid Looping Looping Network Meeting 2nd – 3rd September 2013, Cambridge (UK)

Demonstration of steady state CO2 capture in a 1.7 MWth Calcium looping pilot Arias et al. 2013. International Journal of Greenhouse Gas Control

( in press: doi:10.1016/j.ijggc.2013.07.014)

Process concept :   post‐combustion CaL “standard” scheme

CARBONATORSTANDARDPOWER PLANT

Concentrated CO2

CoalCaCO3 CaO Purge

CaCO3

CaOFlue Gas

Flue gas“without” CO2

Coal Air

O2

AirASU

OXY-CFBCALCINER

Power OUT

Power OUT

CO2

Some contributions of CSIC et al. to this postcombustion technology:• 2000: Process analysis with large make up of limestone (Xave) and typical decay curves (XN vs N)

• 2005: Novel processes options without O2 in calciner.

• 2008: First results from a continuous, interconnected , twin‐ CFB lab. scale facility (0.03 MWth)

• 2012: First results operating long steady state experiments in a 1.7 MWth facility 

Shimizu et al.,  1999

Developing process  leading to “la Pereda 1.7 MWth” pilot

Reactions kinetics, deactivation studies, reactivation methods

Multicycle testing TG  at CSIC

0.03 MWth pilot at INCAR‐CSIC

Twin CFB reactor concept validation in lab scale. Basic reactor and process modeling

Industrial partners

24 m

Status of the pilot plant‐Building finished in September 2011 ‐Start of cold commissioning:  October 2011‐ Start of hot commissioning:   January 2012‐ Operational hours with coal combustion (dual fluidized bed mode):  ~ 1800 h‐ Operational hours in CO2 capture mode : ~ 400 h (approximately 170 h  with the calciner working under oxy‐fuel conditions)

La Pereda CO2 pilot plant: Current status

LA PEREDA CO2 CAPTURE PILOT PLANT: DESCRIPTION

“Development of postcombustion CO2 capture with CaO in large testing facility”

European Union 7th Framework Programme‐FP7

Calciner operating under air or oxy‐combustion conditons

Double loop seal to control solid circulation between 

reactors

Removable cooling bayonet tubes to change heat extraction in reactors

O2 and CO2 tanks and gas mixer, to change oxy‐combustion ratio

Calciner gas heater and indepent steam inyection

Continuous coal and limestone feeding system

Reactor Characteristics:•Height: 15 m•Made of refractory and Carbon Steel•High efficiency cyclones•Fully instrumentallized

Range of conditions during the CO2 capture test:

RESULTS

Carbonator temperature (ºC) 600‐715Carbonator superficial gas velocity (m/s) 2.0‐5.0Inlet CO2 volume fraction to the carbonator 0.12‐0.14Inlet SO2 concentration to the carbonator (mg/m3) 100‐250Inventory of solids in the carbonator (kg m‐2) 100‐1000Maximum CO2 carrying capacity of the solids 0.10‐0.70Calciner temperature (ºC) 820‐950 ºCInlet O2 volume fraction to the calciner 0.21‐0.35Inlet CO2 volume fraction to the calciner 0‐0.75CO2 capture efficiency 0.4‐0.95SO2 capture efficiency 0.95‐1.00

Results from the 1.7 MWth CaL pilot plant of la Pereda

0.80

0.85

0.90

0.95

1.00

3:00 5:00 7:00 9:00 11:00 13:00 15:00

E SO2

0

0.03

0.06

0.09

0.12

0.15

X CaSO4

ESO2 carb

ESO2 calc

ExperimentalCalculated

RESULTS  FROM THE 1.7 MWth CALCIUM LOOPING PILOT PLANT OF LA PEREDA

SO2 capture in the Ca‐looping facility

Results from the 1.7 MWth CaL pilot plant of la Pereda

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0 5 10 15 20 25 30 35

N th

X ave, X

N, X

  CaSO

4

XaveXN (Grasa et al 2006)XCaSO4 experimentalXCaSO4 calculatedCaO utilization

0

0.2

0.4

0.6

0.8

1

11:10 11:20 11:30 11:40 11:50 12:00

E CO2

0

200

400

600

800

1000

1200

Inventory of solids (kg/m

2 )

ECO2 eq

ECO2

Carbonator inventory

Evolution of sorbent utilization including sulfation (Esulf: 95‐100%)

Results from the 1.7 MWth CaL pilot plant of la Pereda

Effect of average sorbent activity on CO2 capture efficiency (Oxyfuel combustion‐calcination mode)

Results from the 1.7 MWth CaL pilot plant of la Pereda

ucarb = 4.0-4.3 m/sTcarb = 660-690ºCXave = 0.21Xave = 0.11

Results: Characterization of the carbonator reactor 

aveaCO

CaOactive Xf

FN

2

eCOsactivecarb ffkE 2

CO2 removed from flue gas = CaCO3 in circulating solids

CO2 removed from flue gas = CO2 reacting with CaO

• A flexible experimental facility is in operation in “La Pereda” tovalidate the postcombustion CaL technology in the MW’s scale

• CO2 capture efficiencies between 80‐90% achievable in a CFBcarbonator reactor operating with “standard” CaO solids, bedinventories, gas velocities, solid circulation rates and reactionconditions in the carbonator and calciner reactors (oxyfuel coalcombustion)

• SO2 capture in the CFB reactors is over 95%. Natural limestones OKfor coal based systems.

• The concept of post‐combustion Ca‐looping, in continuousmode of operation, has been successfully proven with twointerconnected CFBCs at the 1.7 MWth scale

MAIN CONCLUSION

Demonstration of steady state CO2 capture in a 1.7 MWth Calcium looping pilot, Arias et al. 2013. International Journal of Greenhouse Gas Control

in press: doi:10.1016/j.ijggc.2013.07.014)