Nanoparticle.enhanced

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Nanoparticle-enhanced CO 2

capture

IntroductionObjectives

Materials andMethodsG-L Systems andnanouidsNanoparticlesCharacterization

Apparatus

Experiments

ResultsDiffusion isFickianParametersaffecting E p Correlation of results

Conclusions

Acknowledgmen ts

Nanoparticle-enhanced capture of carbon-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 CO 2 capture Oct 04, 2010 1 / 20
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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 of interphase 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 ne particles areknown to cause in gas-liquid transport,

Use well characterized particles so that enhancements dueto the grazing effect can be calculated


M i l d M h d G L S d id
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Materials and Methods G-L Systems and nanouids

Gas-liquid systems studied and absorption regimes

Absorption of CO 2 in

Water: Physical absorption.

Methyldiethanolamine (MDEA ) solutions: slow fasttransition , and Fast reaction regimes Monoethanolamine (MEA) solutions: Instantaneous

reaction regime.


M t i l d M th d G L S t d id
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ExperimentsResultsDiffusion isFickianParametersaffecting E p Correlation of results

Conclusions

Acknowledgmen ts


Nanoparticles and their characteristics

Magnetic Iron oxide: ferrouids: 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 13.2

nm); excellent stability.

Gold colloid: Made from HAuCl 4; 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).


Materials and Methods G L Systems and nanouids
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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 CO 2).

Specic surface: BET.

Surface tension (in the presence of P nanoparticles).


Materials and Methods Apparatus
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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


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Apparatus Liquid lled capillary

Unsteady state absorption into quiescent liquid.

(See gure) Shrinkage of gas slug A gives the rate of masstransfer.

Long contact times (tens of minutes).


Materials and Methods Experiments


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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 CO 2 MDEA Slow Fast Fe 3O 4(L,T,P)

FastCO 2 MEA Instantaneous Fe 3O 4(L,T,P)

O 2 dithionite Slow Fast Fe 3O 4(P)Capillary CO 2 water Physical Fe 3O 4(P); Au; Silica

CO 2 MEA Instantaneous Fe 3O 4(P)

Stirred cell O 2

water Physical Fe 3O 4Olle et al, 2006 Bubble column CO 2 MDEA Instantaneous Fe 3O 4(L,T)

Rajagopal et al, 2007


Results


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Enhancement E p due to nanoparticles

From the measured absorption rates, using the theory of mass transfer with chemical reaction, the physical masstransfer coefficient k L is calculated.

Between WWC and capillary, a range of contact times(hence k L values) can be obtained.

The values in the presence (k L, p ) and absence (k L) of nanoparticles are compared to dene an EnhancementFactor E p due to particles:

%E p = k 0l , p

k 0l 100


Results Diffusion is Fickian
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Is the diffusion in nanouids Fickian?Capillary: Fickian diffusion into a stagnant uid

L1 L2 = 2 D A

c

A

c G E t = Ek Lc

A

Sc G

square root dependence of (L1 L2) on time.

Figure: (a) Fe 3O 4; CO 2 MEA Figure: (b) Gold, phys. absorp.(IIT Bombay) Nanoparticle-enhanced CO 2 capture Oct 04, 2010 13 / 20

Results Parameters affecting E p
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g

E p : Effect of particle hold-up and size

Size and hold-up matter (different uids in WWC)

but so does the depth of diffusion! (P: Capillary)


Results Correlation of results
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A normalized particle size . . . and a correlation

It is the particle size d p in relation to the depth of penetration of solute that is of importance!

Penetration theory: penetration depth with reaction D A t c E

d p = k Ld p E D A= Shm

a modied Sherwood number!

Processing the data to seek a correlation between E p interms of and Sh

m gives:

E p = 1 .519 0. 17Sh0. 16m



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Results: Comparison for Fe 3O 4 with literature

data are from Olle et al., I&EC Re s earc h, 4 5 ,4 35 5 , 20 0 6.(IIT Bombay) Nanoparticle-enhanced CO 2 capture Oct 04, 2010 17 / 20

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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).

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