nanoparticle-enhanced capture of carbon-dioxide … co2 capture introduction objectives materials...
TRANSCRIPT
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Nanoparticle-enhanced capture ofcarbon-dioxide with amine solvents
Srinivas Komati, Syam Sundar and A. K. [email protected]
Department of Chemical Engineering, IIT Bombay.Powai, Mumbai 400076, INDIA.
Symposium on the Global energy future
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 1 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Outline
1 IntroductionObjectives
2 Materials and MethodsGas-liquid systems and nanofluids
NanoparticlesCharacterization
Experimental apparatusExperiments: Regimes and Hydrodynamic conditions
3 ResultsDiffusion is FickianParameters affecting Ep
Correlation of results
4 Conclusions
5 Acknowledgments
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 2 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Introduction
Introduction
• Proven and currently practiced processes for CO2 capturein power generation from coal are based on gas absorption:
• Conventional plants - chemical absorption based on amine(MEA/MDEA/hindered amines) solvents
• Gasification - physical absorption (Selexol/Rectisolprocesses)
• The gas-liquid mass transfer step is an importantdeterminant of the rate at which CO2 can be captured,and hence, of equipment size. Intensification of this step istherefore of interest.
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 3 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Introduction
Why nanoparticles?
• Literature claims anomalous effects of nanoparticles ontransport rates in heat transport and momentum transport.
• Effect of nanoparticles on mass transport: Literaturesuggests an enhancement in rates, but is not conclusive –
• convective mass transport:• often studied in bubbling equipment, and interpreted in
terms of an overall effect on the rate – effect on kL isdifficult to assess.
• Particles of Fe3O4, CuO, Al2O3, SiO2, Cu and Au, ofdifferent sizes (10 to 200 nm) and in differentconcentrations (< 1 to 40%w) have been used.
• conflicting results – results of different groups difficult tocompare.
• Molecular transport: Limited data; qualitative and difficultto interpret.
— if proven, could have potential in the CO2 capturecontext!
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 4 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Introduction Objectives
Objectives of the present study
The objectives stem from the need —
• for systematic studies and to unify results from the fewsuch studies which exist in the literature—
• conduct studies in model contactors and model systems;compare effects in different contactors
• interpret the observations using the established theories ofinterphase transport
• Establish and validate a basis for process design.
— also to examine the systems relevant to CO2 capture.
• to distinguish the effect from those that fine particles areknown to cause in gas-liquid transport,
• Use well characterized particles so that enhancements dueto the grazing effect can be calculated
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 5 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods G-L Systems and nanofluids
Gas-liquid systems studied and absorption regimes
Absorption of CO2 in –
• Water: Physical absorption.
• Methyldiethanolamine(MDEA) solutions: slow → fasttransition, and Fast reaction regimes
• Monoethanolamine(MEA) solutions: Instantaneousreaction regime.
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 6 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods G-L Systems and nanofluids
Nanoparticles and their characteristics
• Magnetic Iron oxide: ferrofluids: Liquid phase co-precipitationfollowed by stabilization by various means —
L: stabilized by Lauric acid: Size 7-13 nm (average 10.1nm);Stable for short times in tert-amines; not verystable in primary and secondary amines.
T: stabilized by TMAOH: Size 10-35 nm (average 21.1 nm);better stability than L.
P: stabilized by grafted polymer: Size 10-16 nm (average 13.2nm); excellent stability.
• Gold colloid: Made from HAuCl4; broad size distribution(12-250 nm; average 110 nm).
• Silica: Sigma-Aldrich; broad size distribution (6-240 nm;average 110 nm); also Ludox HS-40 (14.7 nm) and LudoxSM-30 (11.3 nm).
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 7 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods G-L Systems and nanofluids
Particle and system characterization
• Particle size, its distribution and stability:
• DLS• TEM• XRD and Debye-Scherrer equation• BET
• Reactivity of the particles towards the solute.
• Solubility of the gas (for CO2).
• Specific surface: BET.
• Surface tension (in the presence of P nanoparticles).
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 8 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods Apparatus
Apparatus – Wetted wall column
• Known hydrodynamics; conforms to penetration theory precepts.
• short contact times (order of a sec); dead-end operation.
Experimental setup
Wetted wall
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 9 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods Apparatus
Apparatus – Liquid filled capillary
• Unsteady state absorption into quiescent liquid.
• (See figure) Shrinkage of gas slug A gives the rate of masstransfer.
• Long contact times (tens of minutes).
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 10 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Materials and Methods Experiments
Experiments: Systems, regimes and Hydrodynamicconditions
The systems, apparata and literature results allow a study under –
• different hydrodynamic conditions, and
• different levels of diffusion limitations.
Apparatus System Regime NanoparticlesWWC CO2 − MDEA Slow→ Fast Fe3O4(L,T,P)
FastCO2 − MEA Instantaneous Fe3O4(L,T,P)
O2 − dithionite Slow→ Fast Fe3O4(P)Capillary CO2 − water Physical Fe3O4(P); Au; Silica
CO2 − MEA Instantaneous Fe3O4(P)Stirred cell O2 − water Physical Fe3O4
Olle et al, 2006Bubble column CO2 − MDEA Instantaneous Fe3O4(L,T)
Rajagopal et al, 2007
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 11 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results
Enhancement Ep due to nanoparticles
• From the measured absorption rates, using the theory ofmass transfer with chemical reaction, the physical masstransfer coefficient kL is calculated.
• Between WWC and capillary, a range of contact times(hence kL values) can be obtained.
• The values in the presence (kL,p) and absence (kL) ofnanoparticles are compared to define an EnhancementFactor Ep due to particles:
%Ep =
(k0l ,p
k0l
)× 100
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 12 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Diffusion is Fickian
Is the diffusion in nanofluids Fickian?
Capillary: Fickian diffusion into a stagnant fluid —
L1 − L2 =
[2
√DA
π
c∗A
cG
]E√
t =EkLc∗
A
ScG
— square root dependence of (L1 − L2) on time.
Figure: (a) Fe3O4; CO2 −MEA Figure: (b) Gold, phys. absorp.
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 13 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Parameters affecting Ep
Ep: Effect of particle hold-up and size
Size and hold-up matter —(different fluids in WWC)
but so does the depth ofdiffusion! (P: Capillary)
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 14 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Correlation of results
A normalized particle size . . . and a correlation
• It is the particle size dp in relation to the depth ofpenetration of solute λ that is of importance!
• Penetration theory: penetration depth with reaction√DAtcE
dp
λ=
kLdpE
DA= Shm
– a modified Sherwood number!
• Processing the data to seek a correlation between Ep interms of ε and Shm gives:
Ep = 1.519ε0.17Sh−0.16m
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 15 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Correlation of results
Results for Fe3O4 – this work
Conditions: 0.02% < ε < 1%; 4× 10−6 < Shm < 1.8× 10−3
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 16 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Correlation of results
Results: Comparison for Fe3O4 with literature
— data are from Olle et al., I&EC Research, 45,4355, 2006.(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 17 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Results Correlation of results
Results: Comparison for other nanoparticles
Figure: (a) Wide PSD (10-250nm) gold and silica
Figure: (b) Ludox HS-40 (14.7nm) and SM-30 (11.3 nm).
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 18 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Conclusions
Conclusions
• Nanoparticles in suspension enhance lliquid phase mass transfercoefficients. This work establishes this across several gas-liquidsystems, regimes, in the presence and absence of reaction, andin the presence and absence of flow, for several types ofnanoparticles.
• Extant theories for the effect of fine particles do not explain theenhancements (large and inconsistent values of solutepartitioning on nanoparticles required to fit the data).
• The extent of enhancement depends on particle holdup andparticle size in relation to the depth of penetration in anycircumstance.
• The results suggest that the nanoparticles influence moleculartransport rates.
• Taylor dispersion studies to measure liquid phase diffusivitiesand validation in a bubbling type contactor are in progress.
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 19 / 20
Nanoparticle-enhanced CO2
capture
Introduction
Objectives
Materials andMethods
G-L Systems andnanofluids
Nanoparticles
Characterization
Apparatus
Experiments
Results
Diffusion isFickian
Parametersaffecting EpCorrelation ofresults
Conclusions
Acknowledgments
Acknowledgments
Acknowledgments
• Financial assistance:• Newreka (Pvt.) Ltd.• Ministry of Human Resource Development’s Thrust area
funding.• C3U
(IIT Bombay) Nanoparticle-enhanced CO2 capture Oct 04, 2010 20 / 20