Mass Transfer coefficients -Experimental Evaluation of CO2 Capture with Structure Packing

R Hilda Chávez andR Hilda Chávez andR. Hilda Chávez and R. Hilda Chávez and Javier J. GuadarramaJavier J. Guadarramarosahilda chavez@inin gob mxrosahilda chavez@inin gob mxrosahilda.chavez@inin.gob.mxrosahilda.chavez@inin.gob.mx

Instituto Nacional deInstituto Nacional deInstituto Nacional de Instituto Nacional de Investigaciones NuclearesInvestigaciones NuclearesMEXICOMEXICO

Antecedents

Amine absorption technology is Amine absorption technology is The Kyoto protocol is an The Kyoto protocol is an considered to be viable for low considered to be viable for low pressure flue gas COpressure flue gas CO22 capture capture because of MEAbecause of MEA--COCO22 fast fast

essential step to mitigate the essential step to mitigate the emission of pollutants and the emission of pollutants and the CCS technologies are theCCS technologies are the22

reaction rate.reaction rate. CCS technologies are the CCS technologies are the instruments of COinstruments of CO22 capture and capture and sequestration.sequestration.

MEA absorption processes are MEA absorption processes are associated with high capital and associated with high capital and

qq

The difference betweenThe difference betweenoperating cost because of operating cost because of amount of energy is required for amount of energy is required for solvent regeneration and severe solvent regeneration and severe

The difference between The difference between categories for capturing COcategories for capturing CO22from power plants is depended from power plants is depended gg

operating problems are present operating problems are present such as corrosion and solvent such as corrosion and solvent loss and degradation.loss and degradation.

on fuel treatment, its oxidation, on fuel treatment, its oxidation, COCO2 2 concentration, and gas concentration, and gas pressurepressuregg pressure.pressure.

ObjectivesObjectives

TheThe objectiveobjective ofof thisthis workwork isis toto studystudy COCO22absorptionabsorption byby experimentalexperimental absorptionabsorption column,column,usingusing metalmetal structuredstructured packingpacking materialmaterial namednamedININININ1818.. ThisThis materialmaterial waswas developeddeveloped byby MexicanMexicanNationalNational InstituteInstitute ofof NuclearNuclear ResearchResearch (ININ(ININ byby itsitsNationalNational InstituteInstitute ofof NuclearNuclear ResearchResearch (ININ(ININ byby itsitsacronymacronym inin Spanish)Spanish).. ThisThis materialmaterial waswas comparedcomparedwithwith commercialcommercial structuredstructured packingpacking..

TheThe presentpresent studystudy providesprovides comprehensivecomprehensiveperformanceperformance ofof structuredstructured parkingparking inin COCOperformanceperformance ofof structuredstructured parkingparking inin COCO22absorptionabsorption applicationapplication..

The general method involves contacting a gas stream to an aqueous amine solution which reacts with the CO by acid baseaqueous amine solution which reacts with the CO2 by acid-base neutralization reaction to form a soluble carbonate salt. This reaction is reversible, allowing the CO2 gas to be liberated byreaction is reversible, allowing the CO2 gas to be liberated by heating in a separate stripping column. The elementary steps for the reaction are represented by the following equilibrium reactions:

2H2O H O++OH-2H2OCO2+2H2O

HCO- +H O

H3O++OHH3O++HCO-

3

H O++CO-2HCO 3 +H2OMEAH++H2O

MEACOO- +H O

H3O++CO 23

H3O++MEAHCO -+MEAMEACOO +H2O HCO3

-+MEA

MethodologyMethodologyThe methodology was divided in three parts: The methodology was divided in three parts:

The use of different packings to compare ININ18 The use of different packings to compare ININ18 The use of different packings to compare ININ18 The use of different packings to compare ININ18 material behavior.material behavior.The use hydrodynamic and mass transfer models.The use hydrodynamic and mass transfer models.y yy yGas chromatograph equipment used was Varian 3760 Gas chromatograph equipment used was Varian 3760 with two detectors: flame ionization and thermal with two detectors: flame ionization and thermal conductivity and three chromatographic columns used conductivity and three chromatographic columns used on the type of combustion gases: CHon the type of combustion gases: CH44, C, C66HH1414, CO, CO22 and and CO CO The chromatographs were provided by HPThe chromatographs were provided by HP 5MS 5MS CO. CO. The chromatographs were provided by HPThe chromatographs were provided by HP--5MS 5MS column of 30 meters long with a diameter of 0.25column of 30 meters long with a diameter of 0.25µµm, m, temperature was carried at 35temperature was carried at 35°°C and 5 minutes of C and 5 minutes of temperature was carried at 35temperature was carried at 35 C and 5 minutes of C and 5 minutes of routine. The concentrations were determined by routine. The concentrations were determined by comparing with standard area from standard known comparing with standard area from standard known composition.composition.

On the bases of conventional definitions of mass On the bases of conventional definitions of mass transfer units the height of a gas phase transfer unittransfer units the height of a gas phase transfer unittransfer units, the height of a gas phase transfer unit transfer units, the height of a gas phase transfer unit

and the height of a liquid phase transfer unit and the height of a liquid phase transfer unit respectively are:respectively are:respectively are:respectively are:

U yy −G

GG aKUHTUHρ

==yyyyNTU)( *

21

−=

GeGaρ

Myy )(

LUHTUH == NTUHETPZ *=

LeL

LL aKHTUH

ρ== NTUHETPZ

Hydrodynamic model for hazardous and structured Hydrodynamic model for hazardous and structured packings by Stichlmair et al 1989 and Masspackings by Stichlmair et al 1989 and Masspackings by Stichlmair et al., 1989 and Mass packings by Stichlmair et al., 1989 and Mass

transfer model for structured packings by Bravo et transfer model for structured packings by Bravo et al 1992al 1992al., 1992.al., 1992.

The system studied was MEA at 30 weight percentage in aqueous The system studied was MEA at 30 weight percentage in aqueous solution countercurrent with COsolution countercurrent with CO22 flue gas. The process was carried out flue gas. The process was carried out in an absorption column with dimensions of 4 0 meters of height andin an absorption column with dimensions of 4 0 meters of height andin an absorption column with dimensions of 4.0 meters of height and in an absorption column with dimensions of 4.0 meters of height and 0.3 meters of diameter. 0.3 meters of diameter.

Characteristic of ININ18 structure packing material Characteristic of ININ18 structure packing material as liquidas liquid--gas contact device and others materials gas contact device and others materials qq gg

of Sulzer Ltd.of Sulzer Ltd.Type Stainless steel

Wire gauge 18

Porosity (ε) 0.9633

Geometric area a 418 m2/m3Geometric area ap 418 m2/m3

Diameter 0.252 m

Height 0.19 mHeight 0.19 m

Corrugated angle 45º

HTUOG m 0.317

Mass transfer results

HTUOL m 0.0273

KGae s-1 3.76

KGae s-1 0.2978

Measurement of COMeasurement of CO2 2 absorption percentage absorption percentage versus timeversus time

ININ18 structured packing material as liquid gas contactor

Pressure drop versus gas velocity Liquid holdup versus F-factor

Height of mass transfer unit in gas phase

Height of mass transfer unit in liquid phase

∆P/Z data versus gas flow to Sulzer BX ININ18 and Mellapak 250Y

ht data versus gas flow to Sulzer BX, ININ18 and Mellapak 250YBX, ININ18 and Mellapak 250Y ININ18 and Mellapak 250Y

KGae data versus gas flow to Sulzer BX, ININ18 and Mellapak 250Y

HTUOG versus gas flow, Sulzer BX, ININ18 and Mellapak 250Y

ConclusionsConclusionsThe use of Sulzer BX and ININ18 packings are recommended in order to capture CO2. Both were the most efficient in the mass transfer because they present the lowest values of the column height and the biggest KGae values,

ti l th h ININ18 ki th bi t l f i i t drespectively, even though ININ18 packing was the biggest value of irrigated pressure drop of the studied structured packing types.This was the consequence of their geometric characteristics: bigger porosity and bigger geometric area than Sulzer BX and Mellapak types. The results of CO2 capture system were found to be relatively accurate and reproducible. The increase in kGae value indicates the speed increase in whichreproducible. The increase in kGae value indicates the speed increase in which the solute is transferred into the liquid phase, the highest value of kGae in the region is loaded with a range of 80 to 90% compared to the flooding regimen.In this work was evaluated experimental CO2 removal with MEA absorptionIn this work was evaluated experimental CO2 removal with MEA absorption from CO2-air flue gas by using a set of equipment specifications and operating conditions.

AcknowledgmentsAcknowledgmentsgg

Part of financial support of this work was provided byPart of financial support of this work was provided by Consejo Nacional de Ciencia y Tecnologia (CONACyT),

number project: SEP-CONACyT-CB-82987. Authors are SA G iacknowledgments to IDESA Group due to the reactive

substances donation.

Th k f tt ti !Thank you for your attention!