Pos Combustion
Transcript of Pos Combustion
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Captura, transporte y
almacenamiento de CO2Captura de CO2 por
Prof. Vicente J. Corts
post combusti nMaster en Ingeniera Ambiental
Curso 2012-2013
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Alternativas tecnolgicas para la captura de CO 2 Fundamentos
Absorcin
Adsorcin
Indice
Membranas Estado de desarrollo
Principales retos Proyectos europeos de demostracin
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Alternativas tecnolgicas para lacaptura de CO2
Fundamentos Absorcin
Presentation Outline
sorc n Membranas
Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
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CO2 3-15%
Technology options
CO2 40%
CO2>95%
Adapted from EPRI 2007
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Post-combustion capture: separation CO 2-N2Pre-combustion capture: separation CO 2-H2Oxyfuel combustion (Denitrogenation): pre-separation O 2-N2
- -
Capture Routes: Classification
.(flue gas)
.(shifted syngas)
.(exhaust)
p (bar) ~1 bar 10-80 ~1 bar
[CO 2] (%) 3-15% 20-40% 75-95%
Partial pressure of CO 2 in the flue gases fromexisting power plants is very low
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The challenge: huge scale of operation
Coal feed : 164 x 103 kg/h
Stack gas flow rate : 2.200 x103 kg/h ~ 54 x103 t/dCO2 flow rate : 370.000 kg/h ~ 8,9 x103 t/d
*
500 MW USC Coal Fired Power Station
. ,
*Cryogenic conditions typically 1,7 MPa, -30 oC
Figures for a
500 MW SC Coal Fired Power Station: 12% higher
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Alternativas tecnolgicas para lacaptura de CO2
Fundamentos Absorcin
Presentation Outline
sorc n Membranas
Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
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Postcombustion: basic approach
Compatible with low partial pressure of CO2 in flue gases CO2Deh dration
CO2Deh dration
CO2Deh dration
CO2
N2O2
Air
Coal
CO2 SeparationPower & Heat
CO2
10-14%0.9 g CO2/kWh
NGas CO2 4-5%0.35g CO2/kWh
Suitable for retrofittings and capture-ready conceptsLeading candidate for gas-fired power plants, if required
Learning by doing through easily scalable pilots processing slip streams
Solvent technologies proven on a smaller scale at CPI*
Learning by searching will lead to better solvents and process integration
Applicable to other carbon-intensive industries: oil refining, cement
andCompressionandCompressionandCompression
*chemical process industries
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Technology options for postcombustionCO2 capture
CO2 Separation and Capture
GasSeparation
AdsorberBedsChemical
Microbial/Algal
SystemsMembranesCryogenicsAdsorptionAbsorption
Activated carbonOther2PolyphenylenoxideAmines
1Alumina PolyimidesAmmonia Zeolite, MOFs
Gas
Absorption
Regeneration
MethodsPhysical
Ceramic BasedSystems
PolypropyleneSelexol Pressure SwingRectisol Temperature SwingOther Washing
1. Primary, secondary, tertiary, sterically hindered2. Alkaline compounds, Salts of aminoacids
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Alternativas tecnolgicas para lacaptura de CO2
Fundamentos Absorcin
Presentation Outline
sorc n Membranas
Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
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CO CAPTURE SOLVENT
VENT GAS TO STACK CO2 TO COMPRESSOR
SOLVENTMAKE-UP
LEAN SOLVENT
Absorption schematics
ABSORBER STRIPPING
Uptake of CO2 into de bulk phase of a liquidsolution w/o chemical reaction
ENTALPHY
FLUE GAS (CO2)
RICH SOLVENT(+ CO2)
SPENT SOLVENT
Flue gas contacted with a reagent-containing solventCO2 transfers from the gas phaseinto the liquid phaseCO2 selectively reacts with the
reagent
The CO2-loaded rich solution ispumped to a regenerator vessel to beheatedGaseous CO 2 is stripped (liberated)Lean solution is circulated back to the
absorber
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Chemical vs. Physical Absorption
IEA GHG
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Simplified flowsheet
Source: SINTEF, 2010
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Simplified flowsheet
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Counter current flow through apacked column is most common
Plate towers are also used,mainly in the stripping step*
Types of columns
*Image source: Mass Transfer Operations, R.E. Treybal, (1980) McGraw-Hill
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1. Very high gas flow rates: large columns
2. Large solvent flow rates: important auxiliaries consumption
3. Steam extraction for solvent regeneration: parasitic load of 20-30% *
Absorption technology issues
. 2 3 ppmv required
5. Solvent and reaction products may exit the absorber: potentialimpact on HS&E of nitramines and nitrosamines
* CO2 compression included GCCSI
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Near-term absorption technologies
1. Currently emphasis on absorption on near-term technologies
2. Industrys CO2 capture chemistry knowledge and overall process
experience are both heavily slated towards absorption3. All near-term technologies are solvent based involving either
proprietary amines or ammonia
4. Distinction between these technologies are
Specific capture chemistryProcess configuration and integration into the power plant
5. Near-term technologies have been tested at scales on slipstreams no larger than 5-25 MWe from coal-fired power plants
GCCSI
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Key characteristics
Absorption solvents
To reduce height requirements for theabsorber and/or
Reduce solvent circulation flow rates
High reactivity withrespect to CO 2
Based on a low heat of reaction withLow re eneration
Davidson
CO2
cost
Which directly influences solventcirculation flow rate requirements
High absorptioncapacity
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Absorption solvents
Reduced solvent waste due to thermaldegradation
High thermalstability
Reduced solvent waste due to chemicalReduced solvent
Key characteristics
Davidson
degradation
degradation
Easy and cheap to produceLow solvent costs
Low environmental impact
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Primary and Secondary Amines
2(R-NH2) + CO2 R-NH-COO- + R-NH3+
Two solvent molecules required for each CO 2 molecule sorbedFast rate low ca acit
Amine-based absorption processs
Carbamate
Low T
Example: Mono-ethanol amine, MEA HOCH2CH2NH2
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R3-N + CO2 +H2O R3-NH + HCO3-
One solvent molecule required for each CO 2 molecule sorbedSlow rate romoters re uired hi h ca acit
Bicarbonate
Tertiary and Hindered Amines
Amine-based absorption processs
Example: MDEA ( HOCH2CH2)2NCH2
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Block flow diagram of theEconamine FG+ process using MEA
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Ammonia-based absorption processChilled ammonia
Ammonium carbonate solution + CO2 Ammonium bicarbonate
cooledflue gas
CO2 (g) CO2 (g)
T raise atrelatively high P
A slurry consisting of a liquid in equilibrium with solid ammoniumbicarbonate (NH4HCO3) is produced in an absorber
The slurry releases CO 2 at a relatively high pressure after beingheated in a desorber
(NH4)2CO3 (aq) + CO2(aq) +H2O(l) 2(NH4)HCO3 (aq)(NH4)2CO3 (aq) (NH4)2CO3 (s)
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Ammonia-based absorption process
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High CO2 purity
Tolerant to oxygen and flue gas impurities
Solvents for Post Combustion
Chilled ammonia advantages
No emission of trace contaminants
Low cost, globally available reagent
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Simplified flow sheet ACAP process
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Comparison of Solvent Properties
Cost(US$/lb)
Volatility(atm x 103 at 40C)
Degradation Corrosion
Solvents for Post Combustion
.
MDEA 300 0.003 Moderate Moderate
Ammonia 5 200 None High
PotassiumCarbonate 40 0 None High
Rochelle, 2007
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FUEL100% CO2COMPRESSION
NET OUTPUT34,2%
Absorption technology: energy penalty
Sankey diagram : Postcombustion USC pulverized coal PP
COOLING53,0%
AUXILIARIES3,4%
CAPTURE PROCESS(Enthalpy&Electricity)5,7%
,
0 10 20 30 40 50
REFERENCEPLANTUSC PC
WITH CCS
EFFICIENCY, %
Based on MIT data
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Subcritical power plant50
45
40
35 i e n c y ,
%
50
45
40
35 n c y ,
%
USC power plant
43.3
34.134.3Amine unit(entalphy)
-0.7
-5.0
-3.5Amine unit(entalphy)
CO2Compressor
Amine unit(power)
Absorption technology: energy penalty
Subcritical
30
25
20
E f f i
Ultrasupercritical
30
25
20
E f f i c
i
USCno
Capture
USCwith
CaptureNoCapture
25.1
WithCapture
-5.0 CO2Compressor
-3.5
-0.7
Amine unit(power)
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CCQ: relative increase or decrease in the emission factor of asubstance due to a certain capture technology
Carbon capture quotients
CCQx,y,z < 1 indicates a decrease in emission factor as aconsequence of CCS
yx,
zy,x,zy,x,
noCCSEF
CCSEFCCQ === =
CCQx,y,z Carbon capture quotient for air pollution substance 'x', given energy conversion technology 'y'and CO2 capture technology 'z
EF CCSx,y,z Emission factor reported/estimated for air pollution substance 'x', energy conversion technology'y' and CO2 capture technology 'z
EF noCCSx,y Emission factor for air pollution substance 'x' and energy conversion technology 'y'reported/estimated for the reference plant without CO 2 capture
CCQx
0150
EEA, 2011
Ai ll i i
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Capture quotients for primary energy, CO 2, SO2, NOX, PM and NH3Postcombustion results in no NO X reduction and much higher
emission of other nitrogen compounds
Air pollution impacts
CaptureTechnology
Conversiontechnology
Primary energynew capture CCQCO2 CCQSO2 CCQNOX CCQPM CCQNH3
Post--combustion
NGCC 1.11 0.13 - 1.00 - 1.25-30.30
PC 1.22 0.10 0.15 0.94 0.71 17.50-45.25
Pre-combustion IGCC 1.13 0.11 0.45 0.85 1.00 -
Oxyfuelcombustion
NGCC 1.20 0.02 - 0 - -
PC 1.22 0.05 0.06 0.42 0.06 -
EEA, 2011
P i O li
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Alternativas tecnolgicas para lacaptura de CO2
Fundamentos Absorcin
Presentation Outline
sorc n
Membranas
Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
Ad ti h ti
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VENT GAS TO STACK CO2 TO COMPRESSOR
Adsorption schematics
ADSORPTION DESORPTION
Uptake of CO2 onto the surface of a solid sorbent viaphysisorption or chemisorption in packed or fluidized beds
SORBENTREGENERATION
FLUE GAS (CO2)
SORBENTMAKE-UP
RICH SORBENT(+ CO2)
LEAN SORBENT
SPENT SORBENT
CO2 CAPTURESORBENT
REGENERATION P
ENTALPHY
Ph i ti Ch i ti
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Physisorption vs. Chemisorption
Van der Waals: Weak forces
Covalent bonding: Strong forces, sites necessary
Adsorption beds
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Adsorption beds
Flue gas flows through voidspaces between adsorbentparticles
Regeneration by heating the
Packed beds
2 - a en a sor en
Flue gas diverted to a secondpacked bed
At least two beds are needed
GCCSI
Adsorption beds
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Adsorption bedsFluidized beds
Flue gas flows upwardthrough a column
Adsorbent particles aresuspended in the gas flow
GCCSI
Sorbent circulated betweenabsorber and regenerator
At least two vessels areneeded
Adsorbents characteristics
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Solid (usually granular, beads, pellets) materialSelective for one or more components in the gas phase
High accesible porosity
Large internal surface area (up to 1000-3000 m2/g)
Adsorbents characteristics
Pore size distributions of common clases of adsorbents
Micropores dp< 20 nm
Mesopores 20 nm dp < 500 nm
Macropores dp 500 nm
CO 2collisiondiameter3.996 nm
Adsorbent attributes
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Capacity: the amount of adsorbate taken up by the adsorbent perunit mass ( or volume) of the adsorbentSelectivity: is the ratio of the capacity of one component to that of
another at a given fluid concentrationRegenerability: Necessary to have the the adsorbent operating in sequential
Adsorbent attributes
cycles Related to the strenght of adsorption forces Affects the fraction of the original capacity that is retained :
working capacity
Mass transfer kinetics: fast diffusion of adsorbate requiredMechanically strong to withstand bulk handling and attrition
Working capacity of adsorbents
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Working capacity 1.3%wt 0.3 mole/kg adsorbent
500 MWe Supercritical PS.
160 kmol CO2/minAdsorbent circulation rate 530 t/min
Working capacity of adsorbents
The Achilles Heel of Adsorption processes
Rotary Wheel contactor
Wheel : diameter 10m, depth 1m
1 minute regeneration time
8 wheels in parallel
Adsorbents
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A cage-like structure which admits onlymolecules less than a certain size e.g.13X (pore diameter 7) will admit He,H2, H2O, CO, CO2, N2
For CO2, there is also significant chemi-
Molecular sieves: ZeolitesAdsorbents
Type X or Y Zeolite
Cations ( e.g. Na+)
sorpt on to t e sur ace, w c g ves t erequired selectivity over other gases
Adsorbents
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Metal Oxide clusters connected by organic linkers
MOF-177 soaks up 140% of its weight in CO2
at roomtemperature and reasonable pressure (32 bar)
Metal Organic Frameworks (MOFs)Adsorbents
Li, J.R Coordination Chemistry Reviews 255 (2011) 17911823
Regeneration Options
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PSA : pressure swing adsorption Pressure is varied : high absorption,low desorption
Rapid cycle easily achieved Short cycle times possible: seconds
Regeneration Options
TSA : temperature swing adsorption T is varied : low absorption,
high desorption Rapid cycle requires very fast heat
transfer: difficult to achieve Minimum cycle time: minutes
Others VSA , vacuum swing adsorption:pressure is varied from a
vacuum to value above Patm ESA, electrical swing adsorption: a current is applied
cyclically to a conducting adsorbent such as a carbon
Adsorption technology issues
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Adsorption technology issues
Regeneration energy should be lower relative to solvents buteffects such asHeat capacityWorking capacityHeats of reaction needs consideration
Potential disadvantages:
Particle attritionHandling of large volumes of sorbentThermal management of large-scale adsorber vessels
Adsorption processes are still in the kW range of demonstrationCurrent development of new materials such as metal organicframeworks (MOFs), zeolites and zeolitic imidazolate frameworks(ZIFs) shows promising
GCCSI
Indice
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Alternativas tecnolgicas para la captura de CO 2 Fundamentos
Absorcin Adsorcin
Membranas Estado de desarrollo
Principales retos Proyectos europeos de demostracin
Membrane technology schematics
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gy
VENT GAS CO2
Separation of CO2 from flue gas by selectivelypermeating it through the membrane material
High permeability High selectivity
FLUE GAS GAS (CO2) POLYMER, METALLICOR CERAMIC MEMBRANE
CO2 permeation requires CO 2 partial pressure gradient across the
membraneOption 1: pressurizing the flue gas on one side of the membraneOption 2: applying a vacuum on the other side of the membrane
Option 3: both
Membrane technology issues
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gy
Claimed to potentially offer low energy capture processes
Small foot print for the capture system
Modular design that may allow for flexible operationTesting conducted at scales less than 1 t/day. No public results
Potential fouling of the membrane surfaces from particulatematter
Uncertainty about performance and cost of large-scale efficientvacuum pumps and compressors
Ability to integrate the process into a power plant
GCCSI
Types of membranes for CO2 removal
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1. First Generation:Cellulose acetate (Cynara, UOP, Grace)Polysulfone (Air Products Prism)
Generally spiral wound ~ 3,000 m2 per m3 volume2. Second Generation:
yp 2
o y m es e, Most likely hollow fibers ~ 10,000 m2 per m3 volume Alternatively spiral wound modules
3. Non selective membranes: gas liquid-contactorsLiquid solvent on one sideGas stream on the other side
Membrane Technology
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Spiral Wound Module
~ 3000 m2 per m3 volume
Source: CO2CRC, 2009
Membrane Technology
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Hollow Fibre Modules
~ 10,000 m2 per m3 volume
Fibre 0.1-0.5 mmSkin layer ~0.1 m thick
Source: CO2CRC, 2009
Membrane Technology
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Liquid solvent on one side of the membrane and the gasstream on the other side of the membrane
Gas-Liquid contactor
Membrane is not selective; only separates gas and liquid phasesDiffusion through porous followed by chemical absorption in liquidSize of the pores:
Flue GasMicroporousMembrane Absorption Liquid
CO2
CO2
membrane Small enough so that the liquid will not wet the pores
Membrane Technology
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Gas-Liquid contactor
Source: CO2CRC, 2009
Indice
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Alternativas tecnolgicas para la captura de CO 2 Fundamentos
Absorcin Adsorcin
Membranas Estado de desarrollo
Principales retos Proyectos europeos de demostracin
State of postcombustion development
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Absorption Adsorption Membrane
CommercialUsage in CPI* High Moderate Low/Niche
Operational Hi h Hi h but com lex Low to moderate
GCCSI* Chemical Process Industries
on ence
Primary Sourceof Energy Penalty
Solventregeneration
(thermal)
Sorbentregeneration
(thermal/vacuum)
Compression onfeed and/or vacuum
on permeate
DevelopmentTrends
New chemistry,
thermalintegration
New chemistry,
processconfiguration
New membrane,
processconfiguration
Indice
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Alternativas tecnolgicas para la captura de CO 2 Fundamentos
Absorcin Adsorcin
Membranas Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
Major challenges for postcombustion
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1. Reduction of the large parasitic load imposed on a power plantMostly derived from the energy needed to regenerate thesolventEnergy required for compression is less than that requiredfor capture
2. Development of new chemistry, new process designs, and
All aimed at reducing the energy penalty3. Capital cost reductions, solvent degradation, solvent volatility,
and other
Secondary to the prime issue of reduction in parasitic load4. Identification of amine derivatives and degradation products
effects on HS&ECountermeasures to be developed
GCCSI
Indice
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Alternativas tecnolgicas para la captura de CO 2 Fundamentos
Absorcin Adsorcin
Membranas Estado de desarrollo
Principales retos
Proyectos europeos de demostracin
European demo projects
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BelchatowRotterdam 2
Post180 MDon Valley
180 M
JanschwaldeOxy-PC180 M
COMPOSTILLA
Oxy-CFB180 M
Pre180 M
Porto Tolle
Post100 M
x
? ?
European demo projects
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European demo projects
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Rotterdam Capture: 1.2 MMt CO2/y Storage : depleted gas fields, N.Sea Industrial partners: EON/Electrabel