Direct Oservation of CO 2 Sorption on Argonne Premium Coal Samples Angela Goodman Karl Schroeder Lisa Campus* U.S. Department of Energy (DOE) National Energy Technology Laoratory (NETL) P.O. Box 10940, Pittsurgh, PA 15236 *ORISE Summer Intern, Engineering Department, Carnegie Mellon University, Pittsurgh, PA Third Annual Conference on Caron Capture and Sequestration Alexandria, Virginia May 3-6, 2004
CO 2 sequestration in coal seams CO 2 understanding the mechanism y which CO 2 is stored in coal determining the CO 2 -coal adsorption isotherm quantitatively
What is the nature of the CO 2 coal interaction? Non-specific surface and pore filling? Adsored on the coal surface and asored within the coal organic matrix Specific interaction etween CO 2 and coal functional groups? caroxyl (-CO 2 H, -CO 2 R, -CO 2 Ar) and / or caronyl (>C=O) functional groups? hydroxyl (R-OH, ArOH) groups? Nishino Adsorption of water vapor and caron dioxide at caroxylic functional groups on the surface of coal Fuel 2001 80, 757-764. Adsorption NOT related to hydroxyl groups Found a GOOD correlation etween CO 2 adsorption and caroxyl group content for a set of 20 coals.
Calculating the CO 2 -coal adsorption isotherm using manometric methods T I V P P S R T B n ex = 1 RT m iso c * V R P Z ri ri P Z rf rf V V P Z sf sf P Z Compressiility Factor si si R: reference chamer, S: sample chamer, P: pressure transducer, I: syringe pump, V: vacuum pump, T: thermocouples, B: constant temperature ath n ex = n ex + n ex + n ex + + n n as 1 2 3... = n ex g ρ 1 ρa ex i Adsored Layer Density
Excess Adsorption (mmol/g) MAF 2.5 2 1.5 1 0.5 0 Compressiility Factor (Z) 3) 2) 1) 0 1 2 3 4 5 6 Pressure (MPa) Adsored Layer Density method VDW Solid density estimate ONO- Kondo Model ZGR EOS Adsored layer density (g/cm 3 ) 1.03 1.18 0.996 0.982 1) Z = 1 (ideal gas law) 2) Z value from Air Liquid Gas Encyclopedia, 1976 3) R. Span, W. Wagner, J. Phys. Chem. Ref. Data 25, 6, 1996 Sudindriyo et al, Langmuir 2003, 19, 5323-5331
CO 2 adsorption on coal at high pressures 7 6 5 CO 2 Adsorption on Fruitland and Joppe-1 IX Coals Hall et al. -- Fruitland coal at 115 F Hall, Fitzgerald, and Liang used different atches of Fruitland coal Adsorption, mmol/g 4 3 2 1 Krooss et al. -- Joppe-1IX coal at 104 F All data points assume that the adsored phase density is 1.028 g/cm3 Hall 1994, Asolute: Redlich-Kwong Z Factors Hall Revised, Asolute: Span & Wagner Z Factors Liang 1999, Asolute Fitzgerald 2000, Asolute 0 Krooss, Asolute -1 Gis Excess Adsorption -2 0 500 1000 1500 2000 2500 3000 3500 Pressure, psia
The ATR-FTIR experiment a) ) A s o r a n c e 0.2 2349 2332 2320 3.5 MPa 55 o C a. sored and gaseous CO 2. gaseous CO 2 667 656 c. sored CO 2 (a - ) 2400 2350 2300 2250 720 700 680 660 640 Wavenumer (cm -1 )
Argonne premium coals Pocahontas #3 (low volatile ituminous) and Beulah Zap (lignite). coals are wellcharacterized, providing the research community with a large dataase of physical and chemical properties of coal samples were supplied as powders (-100 mesh). Prepared in an inert environment A s o r a n c e 4000 0.05 Beulah Zap 3500 3270 2918 2841 Pocahontas #3 2913 2853 3000 2500 2000 1500 Wavenumer (cm -1 ) 1377 1030 1590 1000 744 1591 1438 864 804 500
Spectral data indicate that there is no specific CO 2 caronyl nor CO 2 caroxyl interactions. A s o r a n c e 2400 0.05 2335 2322 2335 2322 2350 2332 2320 2332 2320 0.8 MPa, 55 o C a. Beulah Zap (0.2%). Beulah Zap (8.0%) c. Pocahontas #3 (0.1%) d. Pocahontas #3 (0.5%) 2300 700 Wavenumer (cm -1 ) 654 654 656 656 650 Polymers Containing Caronyl and Caroxyl Functional Groups: 2338.0-2339.5 cm -1 Polymers That Don t Contain Caronyl and Caroxyl Functional Groups : 2334.5-2335.5 cm -1 Kazarian et al. Specific Intermolecular Interaction of Caron Dioxide with Polymers J. Am. Chem. Soc. 1996, 118, 1729-1736.
Comparing ATR-FTIR and manometric techniques for CO 2 adsorption on Argonne coals For the manometric method: θ 1 0.8 0.6 0.4 0.2 0 1 0.8 Pocahontas #3 ATR-FTIR Volumetric 0 2 4 6 8 Pressure (MPa) Beulah Zap 55 o C 1. Z values calculated from Span and Wagner EOS 2. Adsored layer density = 1.03 g/cm 3 θ 0.6 0.4 0.2 0 55 o C ATR-FTIR Volumetric 0 2 4 6 8 Pressure (MPa)
Energy of Adsorption Langmuir Equation θ = P + P 1 = e o Q RT o = Nστ o ( 2πMRT) / 12 Technique Coal % Moisture Q (kj/mol) (1/Mpa) ATR-FTIR Beulah Zap 8.0 a 19.9 0.711 ATR-FTIR Beulah Zap 0.2 20.5 0.878 Manometric Beulah Zap 4.0 c 20.2 0.787 ATR-FTIR Pocahontas #3 0.5 a 20.0 0.706 ATR-FTIR Pocahontas #3 0.1 18.8 0.471 Manometric Pocahontas #3 0.5 c 19.9 0.708
Conclusions one type of sorption site for CO 2 physical sorption process (18.8-20.5 kj/mol) the nature of the CO 2 Coal interaction: no specific interactions with coal functional groups. Isotherm shape was generated y ATR-FITR No assumption for the compressiility factor or adsored layer density