University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Pre-, Post- and Oxy-fuel
Combustion Technologies for CO2 Capture
Giorgio Cau
Professor of Energy and Environmental Systems
gcau@unica.it - http://people.unica.it/giorgiocau/
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
CO2 Capture Technologies (first step of CCS)
Ø  Post-combustion: CO2 captured from flue gas
Ø  Pre-combustion:
CO2 captured from fuel
Ø  Oxy-combustion:
combustion with oxygen, CO2 captured from flue gas
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
CO2 Capture Technologies
Source: International Journal of greenhouse gas control 2 (2008) 9–20
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Post-combustion technologies for CO2 removal
CO2 capture from flue gas
Ø  Applied to conventional power plants
Ø  Can be applied to existing plants (retrofit)
Ø  CO2 capture requires specific processes due to both low concentration and low
partial pressure of CO2
Ø  More common separation methods use chemical solvents, for example amines
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Post-combustion technologies for CO2 removal
Conventional technology: Amines
Ø  Organic compounds obtained from ammonia (NH3) substituting one or more
hydrogen atoms with monovalent hydrocarbon radicals
Ø  Amines can be primary, secondary or tertiary,
with formula equal to R-N-H2, R2-N-H and R3-N
where R is the monovalent hydrocarbon
Ø  Monoethanolamine, MEA, Diglicolamine, DGA, Diehtanolamine, DEA, 2-amine-2metil-1-propanol, AMP, or mixtures of amines, for esemple MEA mixed with
metildiethanolamine, MDEA
Innovative technology: Chilled Ammonia
Ø  NH3
Ø  Temperature about 0 °C
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Post-combustion technologies for CO2 removal
Simplified scheme of the CO2 chemical removal section
Source: http://www.sintef.no/Projectweb/BIGCO2/Project-overview/Task-B-Post-combustion-CO2-capture/
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
CO2 capture plants based on chemical solvents operating worldwide
Capacity (ton/h) *
Use of CO2
16,7
Chemical fertilizers
12,5
Sodium carbonate
1
CCS
Indo Gulf Fertiliser (India)
6,5
Urea
I-n-Salah (Algeria)
115
CCS
Kedah (Malaysia)
13,75
CCS
Liquid Air (Australia)
2,5
CO2 for food industry
Lubbock (Texas)
42
EOR
Luzhou (China)
6,7
Urea
Mitchell Energy (Texas)
42
EOR
Nanko (Japan)
6,7
Urea
North American Chemical (California)
33
Sodium carbonate
Northeast Energy (Massachusetts)
13
CO2 for food industry
Rio de Janerio (Brazil)
7,75
CO2 for food industry
Shady Point
8,3
CO2 for food industry
Sleipner
115
CCS
Southeast (New Mexico)
3,75
EOR
Snøhvit
80
CCS
Sumitomo Chemicals (Japan)
7
CO2 for food industry
4,5
Fire extinguisher
Plant
Abu Dhabi
Aua Pan (Botswana)
Esbjerg (Denmark)
Warrior Run
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Capacity (ton/h) *
Use of CO2
16,7
Chemical fertilizers
12,5
Sodium carbonate
1
CCS
Indo Gulf Fertiliser (India)
6,5
Urea
I-n-Salah (Algeria)
115
CCS
Kedah (Malaysia)
13,75
CCS
2,5
CO2 for food industry
42
EOR
Luzhou (China)
6,7
Urea
Mitchell Energy (Texas)
42
EOR
Nanko (Japan)
6,7
Urea
North American Chemical (California)
33
Sodium carbonate
Northeast Energy (Massachusetts)
13
CO2 for food industry
Rio de Janerio (Brazil)
7,75
CO2 for food industry
Shady Point
8,3
CO2 for food industry
Sleipner
115
CCS
Southeast (New Mexico)
3,75
EOR
Snøhvit
80
CCS
Sumitomo Chemicals (Japan)
7
CO2 for food industry
4,5
Fire extinguisher
Plant
Abu Dhabi
Aua Pan (Botswana)
Esbjerg (Denmark)
Liquid Air (Australia)
Sleipner (Norway)
Lubbock (Texas)
Warrior Run
Esbjerg (Denmark)
Snøhvit (Norway)
In Salah (Algeria)
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Pre-combustion technologies for CO2 removal
CO2 capture from fuel
Ø  Primary fuel is converted through reforming processes (natural gas, methanol,
etc.) or gassification processes (coal, TAR, etc.) into a synthesis gas mainly
composed by CO, CO2, H2O and H2
Ø  CO can be converted, through a chemical reaction with steam (“water-gas shift
conversion”) into CO2 and H2
Ø  CO2 is separated through physical absorption processes producting a syngas rich
of hydrogen (CO2 content is negligible)
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Pre-combustion technologies for CO2 removal
Scheme of the CO2 physical removal section
Source: Journal of Petroleum Science and Engineering, Vol. 94–95, 2012, Pp. 123–154
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Pre-combustion technologies for CO2 removal
Main physical solvents
Selexol
Ø  DEPG (dimetylether of glycol polyethylene)
Ø  Patent of UoP
Rectisol
Ø  Based on methanol, developed by Lurgi and Linde.
Ø  Operating temperature very low (in the range -40/-60 °C)
Ø  Greater CO2 solubility
Purisol
Ø  NMP (N-Methyl-2-Pyrrolidone), patent of Lurgi AG
Ø  Maximum selectivity for H2S and CO2
Fluor SolventTM
Ø  Based on Propylene Carbonate
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Pre-combustion technologies for CO2 removal
Main CO2 capture plant based on physical solvents
CVR Energy coal-to-ammonia plant in Kansas
Ø  Selexol
Ø  128 ton/h of CO2 for urea production
Great Plains Synfuels Plant
Ø  Rectisol
Ø  520 ton/h of CO2 used for EOR
Shenfu Dongsheng
Ø  Greatest Rectisol plant operating worldwide
Ø  Coal to liquid
Ø  1065 ton/h of CO2 operating at 34 bar for EOR
Pernis refinery (127 MW IGCC project) - Netherlands (Shell Gasification)
Ø  50% of captured CO2 is wasted in atmosphere
Ø  50% of captured CO2 is stored
Ø  Pernis can be considered the only one IGCC plant sequestration-ready worldwide
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Oxy-combustion technologies for CO2 removal
Combustion with oxygen
Ø  Nitrogen absence in the comburent leads to flue gas with a very high CO2
concentration (theoretically up to 95% by volume on a dry basis in case of coal and
up to 98% in case of natural gas)
Ø  Oxygen combustion causes a great increas of the combustion temperature
requiring a diluent to substitute nitrogen
Ø  Different solutions are possible:
Recicling of combustion products (oxy-combustion plants of 1st and 2nd generation, with
gas recycling up to 80%)
§  Injection of water or steam (oxy-combustion plants of 3rd generation)
§
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Oxy-combustion technologies for CO2 removal
Technology development
Ø  1st generation plants.
Generally pilot plants derived from “retrofit” of conventional existing plants.
The best known is the 30 MWt plant built by Vattenfall at the Schwarze Pumpe plant
in Germany
Ø  2nd generation plants.
New plants, designed for oxygen combustion and with gas recycling. These plants
are based on experience from 1st generation plants.
Lower size in comparison to 1st generation plants resulting from lower volume flow
in comparison to air combustion (20-25%) due to different gas properties (density
and specific heat capacity)
Ø  3rd generation plants. New plants with oxygen combustion moderated by steam
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Vattenfall di Schwartze Pumpe plant - Germany
Source: Int. Journal of greenhouse gas control 2 (2008) 9–
20
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Oxy-combustion technologies for CO2 removal
Some fundamental issues
Ø  Oxygen production. It is required a plant for oxygen production, generally a
criogenic air separation unit (ASU), with oxygen purity of about 95% in volume
Ø  Combustion. Combustion devices must be suitable for combustion with oxygen
and gas recycling
Ø  CO2 capture. CO2 is easily separated from flue gas through steam condensation. A
separation system for uncondensable gas (mainly sulphur oxides) and a
compression system to assure a proper CO2 pressure for transport and storage are
required
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Energy penalties of CO2 Capture Technologies
Ø  Oxy-combustion. Energy penalties about 7-10 percentage points of the plant
global efficiency, mainly due to:
§
ASU electrical consumption
§
Electrical consumption of CO2 compression chain
Ø  Post-combustion. Energy penalties about 10-11 percentage points of the plant
global efficiency, mainly due to:
§
Thermal energy request due to solvent regeneration process (steam extraction from steam
turbine causing power plant reduction)
§
Electrical consumption of CO2 compression chain
Ø  Pre-combustion. Energy penalties about 8-10 percentage points of the plant global
efficiency, mainly due to:
§
§
Electrical consumption for cooling solvent system
Electrical consumption for CO2 compression chain
§
CO-Shift process (thermal absorption and reduction of syngas chemical power)
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014
University of Cagliari
Department of Mechanical, Chemical and Materials Engineering
http://www.unica.it/
Thank you for your attention
Giorgio Cau
gcau@unica.it - http://people.unica.it/giorgiocau/
Workshop: Mitigazione dei cambiamenti climatici. Il ruolo delle tecnologie “Carbon Capture and Storage”
Sotacarbo - Carbonia – 27 Novembre, 2014