Why Isotherm Measurements are Important? Inter-laboratory Partners. sorption on moisture-equilbrated Argonne premium coal

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1 Carbon Dioxide Storage in Coal Seams: High-ressure -Coal Isotherm Uncertainties Angela Goodman roject artners: Oklahoma State Univerty TICORA Geosciences CSIRO, Australia Univerty of Btish Columbia, Canada Aachen Univerty, Germany Why Isotherm Measurements are Important? Measurement of adsorption on coal produces an isotherm that gives the gas storage capacity as a function of pressure Important for carbon sequestration storage estimates The research community lacks a standard method for determining carbon dioxide adsorption isotherms Unknown affects of: Different Apparatus (manometc, volumetc, and gravimetc) Different rocedures Different Operators Sixth Annual Conference on Carbon Capture and Sequestration Sheraton Station Square May 7-10, 2007, ittsburgh A How reproducible are these measurements? Inter-laboratory compason of sorption on moisture-equilbrated Argonne premium coal Six participants Coal samples (three) from Argonne remium Coal Sample rogram Same procedure followed by each group Isotherms collected with each lab s pemental apparatus MAIN Goal Determine the reproducibility of sorption isotherms MAIN Concluon At pressures above 8 Ma, sorption isotherms diverged gnificantly articipants G. Duffy, R. Sakurovs, S. Day B.M. Krooss, A. Busch, Y. Gensterblum Inter-laboratory artners Affiliation CSIRO Australia Aachen Univerty, Germany K.A.M. Gasem, R. L. Oklahoma State Univerty, OK Robinson, Jr., J.E. Fitzgerald, C. Jing, S. Mohammed T. ratt, C. Hartman TICORA Geosciences, Colorado M. Bustin, L. Chikatamarla Univerty of Btish Columbia Slava Romanov, K. Schroeder, C. White U.S. DOE-NETL, USA Coal (100 mesh) Argonne remium Coal Samples Rank %C MAF % Moisture % Ash ocahontas #3 Low ol. Bit Illinois #6 High ol. Bit Beulah-ap Lignite Moisture-Equilibration rocedure ASTM procedure D Standard Test Method for Equlibum Moisture of Coal at ercent Relative Humidity Modifications Moisture equilibrated at 55 o C Handled coals under nitrogen environment ocahontas No. 3 and Illinois No. 6 were equilibrated for 72 hours and Beulah ap was equilibrated for 48 hours. Exception: lab 6 used Beulah ap and ocahontas No. 3 as-received from the Argonne coal bank

2 Moisture-Equilibrated Coals Moisture-Equilibrated Coals Moisture-Equilibrated Coals Moisture-Equilibration Results Moisture contents of the coal samples vaed gnificantly among the labs and from the asreceived moisture contents of the as-received Argonne samples. Small modifications of the ASTM procedure has an unpectedly large effect on the interlaboratory reproducibility for the coal moisture equilibration content -Coal Isotherm rocedure Equipment to Measure Sorption Isotherms Used their own apparatus manometc (four labs), volumetc (one lab), and gravimetc (one lab). Manometc Technique I Gravimetc Technique Same conditions: moisture-equilibrated coals 55 o C 2000 pa (14 Ma) T R R: reservoir chamber, S: sample chamber, : pressure transducer, I: synge pump, : vacuum pump T: thermocouples B: constant temperature bath S B T

3 Differentiating Between the Reference olume, Sample olume, and oid olume reference volume: sample cell volume: reference void = sample cell - sample 100% LAB 1 LAB 2 LAB 3 LAB 4 LAB 5 LAB 6 Coal Mass (g) Equilibration Time > 2hours 30 min 6 hours 4-12 hours 60 min 6-12 hours 90% pressure transducer pressure transducer olume 80% 70% 60% 50% reference void reference coal void sample cell 40% 30% 20% coal 10% 0% Laboratoes

4 Coal Isotherm Results Isotherm measurements up to 15 Ma Agreement between the labs are in fair agreement with the ceptions of labs 2 and 4 No obvious planation for labs 2 and 4 Manometc degn, sample mass, cell volumes, moisture content Isotherm measurements below 8 Ma Minor ceptions: labs 3 and 4 for ocahontas No. 3 and lab 2 for Illinois No. 6 Calculating the Amount of Adsorbed (n = Gibbs Excess Adsorption) = nrtz rf = R 1 z z rf * z n = Δn + Δn + Δn Δn i z m c Mass of coal, g T iso Isothermal temperature, K n Number of moles of gas R Reference cell volume, cm 3 r i Initial reference cell pressure, Ma oid volume, cm 3 r f Final reference cell pressure, Ma zr i Initial reference real gas compresbility factor 3, i f s Initial sample cell pressure, Ma zr Final reference real gas compresbility factor 3, f i s Final sample cell pressure, Ma zs Initial sample real gas compresbility factor 3, R Molar gas constant, J K -1 zs f Final sample real gas compresbility factor 3, Technical Challenges Excess Sorption: Compresbility Factor () = R 1 * rf rf Technical Challenges Excess Sorption: oid olume = R 1 * rf rf Excess Adsorption (mmol/g) MAF ) Beulah ap 22 o C 2) 1) ressure (Ma) 1) = 1 (ideal gas law) 2) value from Air Liquid Gas Encyclopedia, ) R. Span, W. Wagner, J. hys. Chem. Ref. Data 25, 6, 1996

5 roblems with sorption of on coal swells coal (Larsen, 2004, Karacan 2003, Laximinarayana 2004, Harpalani 2004, Reucroft 1987, 1986 ) dissolves in coal and water (Larsen 2004, Duan 2003) alters the coal chemically (Burruss 2006) causes coal phycal structure rearrangement (Karacan 2003, Goodman 2006) shnks coal (Ozdemir 2003) Currently a fundamental model that descbes sorption behavior in the superctical region is still misng (Siemons and Busch 2006) The Adsorption Isotherms Appear to Be Combinations of a Surface Adsorption Term and a Constant Term abs n ρ = 1 a n + ρδ ρ n ads = Dubinin Astakov n abs = n t K s ln oe Isotherm Model Excess Adsorption (mmole/g-coal, daf) Best Fit Ung the Modified Dubinin-Astakov Equation Absolute Adsorption olumetc Effects ressure, Ma Small effect at low pressure Importance of olume Effects to Adsorption Isotherms of Carbon Dioxide on Coals Ozdemir,Ekrem; Mor,Badie I.; Schroeder,Karl Langmuir 19, (2003) Concluons: Inter-laboratory compason of adsorption isotherms Inter-laboratory rovided first inter-laboratory compason for sorption on moisture-equilibrated coals 4 out of 6 labs agree within 30% Above 8 Ma, sorption isotherms deviate gnificantly Further studies are needed to address deviations and pemental problems for high-pressure sorption A. L. Goodman, A. Busch, M. Bustin, L. Chikatamarla, S. Day, G. J. Duffy, J.E. Fitzgerald, K.A.M. Gasem, Y Gensterblum, C. Hartman, B.M. Krooss,. an, T. ratt, R. L. Robinson, Jr.,. Romanov, R. Sakurovs, K. Schroeder, M. Sudibandyo, C. M. White Inter-laboratory Compason II: CO2 Isotherms Measured on Moisture-Equilibrated Argonne remium Coals at 55oC and 15 Ma published online at