www.process-design-center.com
Post-Combustion Carbon CaptureRaf Roelant
CCUS TrainingBreda, February 19, 2020
Specialists in Process Development
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Post-combustion carbon capture
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Compared to pre-combustion carbon capture:
+ Allows retrofitting existing plants,
− Hich OPEX (energy!) and CAPEX (especially for flue gases with low CO2 conc.)
Separation of CO2:
• Most challenging: separation of CO2 from noncondensable 𝐍𝟐.• Usually at low temperature:
• Enhances interaction with a separating agent
• Relatively easy retrofitting
• Usually relies on acidity of CO2.
C𝑚H𝑛S𝑝 + O2 + N2 + Ar → H2O + CO2 + SO𝑥 + NO𝑥 + N2 + Ar
Combustion of fossil fuels:
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“Post combustion”?
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By extension, as sources of CO2 :
Similar flue gases, with CO2 concentration typically lower than 30 vol%.
Iron reduction through cokes, part of steelworks,
Lime calcination, part of cement production, ...
H2O + CO2 + SO𝑥 + NO𝑥 + N2 + Ar
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CO2 emission breakdown
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Fifth assessment report of the IPCC (2014), Working Group III contribution.
Agriculture,
Forrestry and other
Land Use
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Beyond scope of this presentation
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Some industries produce relatively pure CO2 streams, e.g.,
• Hydrogen production by steam methane reforming,
• Direct reduced iron (DRI) production.
Not surprisingly, such streams are being stored at industrial scale.
E.g., Al Reyadah, Abu Dhabi, UAE, using 800 kt-CO2/y from DRI production (Emirates Steel)
for enhanced oil recovery since 2009.
Some natural gas sources are high in CO2 and need treatment to have this CO2 removed.
In some cases the CO2 stream is stored.
E.g., Equinor (formerly STATOIL), Sleipner Vest field, NO, storing 1 Mt-CO2/y since 1996!
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Largest CO2 sources in Energy and Industry
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Approximate CO2 emission
(Gt-CO2/y)
Share of anthropogenic CO2emissions
Power plants
(coal-fired, natural-gas-fired)
10 28 %
Steel mills 3.3 9 %
Cement plants 2 5.5 %
Oil refining 1 3 %
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Potential adopters in NL
- Coal-fired power stations• Incl. 3 recent large ones, ‘capture-ready’ with storage offshore considered:
• Riverstone Centrale Rotterdam (previously Engie). Ca. 800 MW (2015)• Uniper MPP3 Energiecentrale Rotterdam. Ca. 1070 MW (2016)• RWE Eemshavencentrale. Ca. 1560 MW (2015)
- Tata steel IJmuiden (7.5 Mt-steel/y)- 5 oil refineries in Port of Rotterdam, one in Vlissingen
(63.5 Mt-products/y combined)
- (Petro)chemical industry: Nouryon, SABIC, Teijin Aramid, ...
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Potential adopters in BE
- (No coal-fired power stations remaining!)- Steel plants: ArcerorMittal Gent (5 Mt-steel/y) and Liège (1.8 Mt-steel/y)- Cement plants: 4 in Hainaut province, one near Liège (6 Mt-cement/y
combined)
- Oil refineries: 4 in Port of Antwerp (30 Mt-products/y combined)- (Petro)chemical industry, many in Antwerp: BASF, Ineos, BP, ...
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Post-combustion carbon capture
Technology classes
1.Absorption2. Adsorption
3. Membrane separation
4. Cryogenic separation
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Absorption (scrubbing)
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Desorption effectuated by
• Heating and/or
• Letting down pressure.
(Simplified PFD)
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Absorption (scrubbing)
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Chemical absorption Physical absorption
• Amine (Shell CANSOLV, MHI KM CDR, ...),
• Chilled ammonia (GE Power’s CAP),
• Aqueous carbonate (Honeywell UOP’s Benfield),
• Sodium hydroxide, potassium hydroxide
• Dimethyl ethers of polyethylene glycol (UOP
Selexol)
• Refrigerated methanol (Air Liquide Rectisol)
• Propylene carbonate (Fluor Solvent Process)
Relatively high regeneration energy Low regeneration energy
Most technologies allow deep CO2 removal For bulk CO2 removal
Works for low CO2 partial pressures Needs high CO2 partial pressures
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Absorption (scrubbing)
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Chemical absorption Physical absorption
• Amine (Shell CANSOLV, MHI KM CDR, ...),
• Chilled ammonia (GE Power’s CAP),
• Aqueous carbonate (Honeywell UOP’s Benfield),
• Sodium hydroxide, potassium hydroxide
• Dimethyl ethers of polyethylene glycol (UOP
Selexol)
• Refrigerated methanol (Air Liquide Rectisol)
• Propylene carbonate (Fluor Solvent Process)
Relatively high regeneration energy Low regeneration energy
Most technologies allow deep CO2 removal For bulk CO2 removal
Works for low CO2 partial pressures Needs high CO2 partial pressures
More suitable for CO2 removal from
pressurised natural gas, syngas
Also works best at high pressure
Very high regeneration energy
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Chemical absorption Physical absorption
• Amine (Shell CANSOLV, MHI KM CDR, ...),
• Chilled ammonia (GE Power’s CAP),
• Aqueous carbonate (Honeywell UOP’s Benfield),
• Sodium hydroxide
• Dimethyl ethers of polyethylene glycol (UOP
Selexol)
• Refrigerated methanol (Air Liquide Rectisol)
• Propylene carbonate (Fluor Solvent Process)
Relatively high regeneration energy Low regeneration energy
Most technologies allow deep CO2 removal For bulk CO2 removal
Works for low CO2 partial pressures Needs high CO2 partial pressures
Absorption (scrubbing)
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Amine absorption
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Chemistry1. Carbamation
2 R − NH2 + CO2 → R − NH3+ + R − NHCOO−
• Dominant reaction for primary amines, sterically hindered for secondary amines, impossible for tertiary amines.
• ½ mole of CO2 absorbed per mole of amine.
2. BicarbonationR − NH2 + CO2 + H2O → R − NH3
+ + HCO3−
• Negligible for primary amines.
• 1 mole of CO2 absorbed per mole of amine.
3. Carbonic acid formationCO2 + H2O → H2CO3
• Negligible for primary amines.
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Amine absorption
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NH2
OH
OHOH
CH3
NH
CH3
CH3
OHOH
N
Primary amines,
E.g., monoethanolamine (MEA)
Secondary amines,
E.g., diisopropylamine (DIPA)
Tertiary amines,
E.g., methyldiethanolamine (MDEA)
CO2 absorption
capacity
Ease of
regeneration
Absorption
rate
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Amine absorption
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Solvent:
• Amines dissolved in water, typically at 30 wt%.
• Different amines are being mixed to combine their advantages.
• Rate promoters are being added, e.g.,
Solvents are often a secret mixture, e.g.,
• Shell CANSOLV DC201,
• Mitsubishi Heavy Industries KS-1.
NH
NH
Piperazine
OH OH
OH
B
Boric acid
NH2
OH
OHOH
CH3
NH
CH3
CH3
OHOH
N
Primary amines,
E.g., monoethanolamine (MEA)
Secondary amines,
E.g., diisopropylamine (DIPA)
Tertiary amines,
E.g., methyldiethanolamine (MDEA)
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Amine absorption
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Amine absorption
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• As yet the only post-combustion capture technology applied at industrial scale,
At coal-fired power stations, with CO2 used for on-shore Enhanced Oil Recovery (EHR):
• 1 Mt-CO2/y: SaskPower, Boundary Dam Power Station, Estevan, Sask., CAN, since 2014.
• CO2 transported to Weyburn field for EOR via 66 km pipeline.
• Shell CanSolv® technology
• 1.6 Mt-CO2/y: Petra Nova project, A. Parish power plant, NRG Energy & JX Nippon Oil & Gas
Exploration, Thompsons, TX, USA, since 2016.
• CO2 transported to West Ranch field for EOR via 130 km pipeline.
• KM-CDR® technology
• Cost typically estimated at 50 to 100 €/t-CO2 incl. storage.
• Amine CO2 absorption technology also has a proven industrial record outside post-combustion
carbon capture:
• For natural gas treatment: Statoil’s Sleipner (0.9 Mt-CO2/y, since 1996) and Snøhvit (0.7 Mt/y,
since 2008) fields, NO; Chevron, Barrow Is., AUS (4 Mt/y, since 2016)
• In hydrogen production: Shell, Scotford, Alta., CAN (1.2 Mt/y, since 2015)
Maturity
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Amine absorption
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Petra Nova project, A. Parish power plant, NRG Energy & JX Nippon Oil & Gas Exploration,
Thompsons, TX, USA
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Amine absorption
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Flue gas duct
Scrubbing tower
(116 m)
Stripping tower
Quench tower
Petra Nova project, A. Parish power plant, NRG Energy & JX Nippon Oil & Gas Exploration,
Thompsons, TX, USA
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Chilled ammonia process
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- Ammonia (typically 10-15 wt%) in water, possibly with ammonium carbonate- CO2 absorption products may exceed solubility limit (then slurry)- Near-freezing conditions (0°C-10°C) to reduce ammonia slip and increase solvent loading- Compared to amines:
+Lower regeneration energy,
+Cheaper solvent,
+No toxic degradation products,
−Difficult to remove CO2 deeply.
Technology demonstrated at ± 100 kt-CO2/y scale (Alstom, now GE Power). Further upscaling on hold.
Maturity
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Post-combustion carbon capture
Technology classes1. Absorption
2.Adsorption3. Membrane separation
4. Cryogenic separation
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Adsorption: sorbents
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Most investigated: low temperature sorbents:
• Amine functionalised silica, alumina, polymers
• Activated carbon
• Zeolite 13X
• Metal-Organic Frameworks (MOFs).
Compared to amine absorption:
+ Faster capture,
+ Higher capacities,
+ Less solvent degradation,
+ Often lower energy penalty, or use of waste heat,
− Often lower CO2 fraction captured, lower CO2 selectivity,
− Solids more difficult to handle than liquids.
High temperature sorbents have also received attention
(chemical looping: carbonation at ± 600°C, calcination at ± 900°C).
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Adsorption: process configurations
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1. Temperature-swing (TSA),
2. Pressure/vacuum-swing (PSA, VSA),
or a combination thereof (PTSA, VTSA).
1. Fixed beds (batch operation),
2. Moving beds (operation ~ distillation column),
3. Simulated moving beds,
4. Fluidised beds.
Tested at pilot scale for amine-functionalised porous solids:
• Moving bed: Kawasaki Heavy Industries, 3.5 t-CO2/d,
• Bubbling fluidised bed: TU Vienna-Shell, 1 t-CO2/d.
Challenges in upscaling:
• Solids engineering: flow, heat exchange (especially cooling)
• Water vapour often reduces adsorption capacity
Maturity
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Adsorption: fluidised bed
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Kawasaki CO2 Capture. Okumura et al. Energy Procedia 114 (2017) 2322-2329.
60°C vacuum steam!
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Adsorption: fluidised bed
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TU Vienna-Shell. Pröll et al. Chem. Eng. Sci. 141 (2016) 166-174.
Flue gas
Treated flue gas
120°C atmospheric steam
CO2 + steam
Adsorption Desorption
Cooling Heating
Cooling Heating
Sorbent
risers
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Post-combustion carbon capture
Technology classes1. Absorption
2. Adsorption
3.Membrane separation4. Cryogenic separation
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Membrane separation
Compared to adsorption:
+ No heating/cooling needed,
+ No wastewater,
− Typically limited selectivity
− Less suitable for deep CO2 removal
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Membrane separation (low temperature)
• Polymeric membranes most mature- Cellulose acetate/triacetate, polyimide, sulfonated polyetheretherketone (SPEEK), polyvinylamine,- Transport by solution-diffusion,- Usually dense, sometimes microporous (microporous organic polymers; MOPs),- Sometimes supported.
•Others:- Carbon molecular sieve (CMS) membranes, zeolite molecular sieve membranes, silica- Fixed-site carrier (FSC) membranes, e.g., Amine-grafted polymer,- Mixed matrix membranes, typically zeolites, ZIFs, MOFs, CMS, nanotubes, mesoporous and dense
silica, mixed-metal oxides embedded in polymers,
- Supported liquid membranes (SLMs),- Hybrids....
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Industrial scale?
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Tested at pilot scale (± 1 t-CO2/d):
• Membrane Technology Research: spiral-wound polymeric membrane,
• EU funded NanoGLOWA Project: hollow fibre polymeric, FSC membranes,
• ...
Main challenges in upscaling:
1. Reducing thickness while preserving selectivity,
2. Large-scale production of defect-free membranes and modules (automation!),
3. Chemical resistance (SOx, NOx, H2O).
Polymeric membranes applied industrially for natural gas sweetening, but here the feed is pressurised!
Maturity500-1000 m²/m³ 1500-10000 m²/m³
Spiral-wound modules Hollow-fibre modules
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Membrane separation
Technology classes1. Absorption
2. Adsorption
3. Membrane separation
4.Cryogenic separation
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Cryogenic separation
•Not economical by itself:Prior CO2 concentration needed lest entire flue gas stream needs chilling.
• Selective condensation of solid CO2 or liquid CO2 (depending on pressure),•Option to reduce cost: integrate cryogenic capture with LNG regasification.
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Hybrid with membrane technology demonstrated at pilot scale (Air Liquide, ± 25 t-CO2/d in US DOE’s
National Carbon Capture Center, Wilsonville, AL):
• Polyimide membrane operated below −20°C, which improves selectivity, but maintains permeance,
• Liquid CO2 condensation from permeate at −57°C.
Maturity
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Cryogenic separation
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Air Liquide’s Cold Membrane technology.Hasse et al. Energy Procedia 63 (2014) 186 – 193.
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Conclusion
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• Technogy to beat: Amine absorption- As yet only post-combustion technology applied at industrial scale:
± 1 Mt-CO2/y. Cost typically estimated at 50 to 100 €/t-CO2 incl. storage.
- Technology providers: Shell, Mitsubishi Heavy Industries, Kerr-McGee/ABB Lummus, Fluor...- Main weakness: high energy penalty: main aspect being challenged by other, emerging technologies.
• 2nd maturest: Chilled Ammonia absorption- Demonstrated at ± 300 t-CO2/y by Alstom, now GE Power.
• Emerging technologies, all demonstrated at pilot scale(1 to 25 t-CO2/d):
- Adsorption: Kawasaki Heavy Industries, TU Vienna-Shell, ...- Membrane separation: Membrane Technology Research, ...- Cold membrane separation: Air Liquide
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Acknowledgement
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The author represents the GRAMOFON project. This project has
received funding from the European Union’s Horizon 2020 research
and innovation programme under grant agreement No 727619.