Topical Workshop for PhD students Adsorption and Diffusion in MOFs Institut für Nichtklassische Chemie, Germany,

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1 Gas Separaton and Purfcaton Measurement of Breakthrough Curves Topcal Workshop for PhD students Adsorpton and Dffuson n MOFs

2 Adsorpton on Surfaces / Separaton effects Useful features Thermodynamc effect (dfferences between the sorpton capactes) Knowledge of Isotherms Knetc effect (dfferences between the sorpton veloctes) Knowledge of transport coeffcents Sterc effect (molecular seve effect) Knowledge of geometry

3 Industral applcaton of Adsorpton Gas separaton (Ar to Oxygen and Ntrogen, Iso-alkanes and n-alkanes) Gas purfcaton (dryng of natural gas, hydrogen etc.) Recovery of organc compounds (toluene, hydrocarbons etc.) Envronmental (organc solvents from waste ar etc.)

4 Industral applcaton of Adsorpton choce of adsorbent optmal gas fluxes cycle tme product qualty energy costs adsorber to clean natural gas

5 Bascs of Sorpton Technque / Processes Temperature swng process (TSA) Desorpton by ncrease of T (A to D) amount adsorbed A to B: pressure swng / purge wth ntert gas A to D: temperature swng A to C: mx of both B C pressure A D T1 T2 > T1 Hot nert gas Water vapor Electrcal heatng Pressure swng process (PSA / VPSA) Desorpton by decrease of p (A to B) PSA adsorpton at hgher pressures (>3 bar); regeneraton at atmospherc pressure (1) VPSA adsorpton at hgher pressures (>1,2 bar); regeneraton under vacuum (ca.,2 bar) (1) Combned TSA-PSA Desorpton by ncrease of T and decrease of p (A to C) (1) (1) D. Bathen, M.Bretbach, Adsorptonstechnk, Sprngerverlag, 21

6 Pressure Swng Adsorpton (PSA) Knowledge of: Isotherms Heat of adsorpton Knetcs Coadsorpton producton Adsorber A regeneraton Adsorber B Predcton of Breakthrought Curves

7 Pressure Swng Adsorpton (PSA) producton Adsorber B regeneraton Adsorber A Knowledge of: Isotherms Heat of adsorpton Knetcs Coadsorpton Predcton of Breakthrought Curves

8 Modelng Output Fnal Concentraton Pressure Drop Operatonal Condtons Pressure (1. bar) Temperature (296 K) Feed Flow (3.3 cm³/s) Molar Fracton (13%) Column Axal Dsperson Bed Porosty Feed Flow Speed Intal Concentraton Adsorbent Data Av. Partcle Dameter (.3 cm) Specfc Volume (.39 cm³/g) Packed Bed Data Bed Geometry Apparent Densty (1.8 g/cm³) Porosty (.4)

9 Modelng Heat Exchange Flud Heat Capacty Gas - Sold Wall Envronment Mass Transfer Coeffcent Axal Dsperson Sold - Sold Convecton of Heat and Mass (Flow) Wall Conducton Sold Heat Capacty Mass and Heat Transfer Thermophyscal Data Heat of Adsorpton (-29.3 kj/mol) Heat Transfer Coeffcents Heat Capactes Densty and Vscosty Adsorpton Isotherm Parameters Adsorbent Partcle

10 Expermental Setup measurements of pure gases measurements of mxtures Magnetc couplng balance from Rubotherm GmbH Volumetrc system wth two vessels and an adsorpton chamber (workng room)

11 Expermental Setup measurement of pure gases Gravmetry: Mass varaton Evaluaton of equlbrum and knetcs

12 Preparaton of samples,2 4,2 4 change of mass [g],1, -,1 -, temperature [ C] change of mass [g], -,2 -,4 -,6 -, temperature [ C] -, tme [mn] -, tme [mn] Actvaton of Slcalte-1 Actvaton of NaCaA Evacuaton of the samples wthn the expermental setup Heatng wth 1 K/mn up to max. 37 C Slow coolng down of the crystals (ca. 1K/mn) Should be avod cracks n the bg crystals

13 Uptake-curves from measurements of sotherms,2 sgnal of balance [g],15,1,5, tme [mn] Uptake for the determnaton of equlbrum data Increasng of pressure after constant mass Mass s a functon of pressure at constant temperature Heght of each step s of nterest

14 Isotherms amount adsorbed [mmol/g] 2, 1,5 1,,5, n-butane 1E-4 1E-3,1,1 1 1 pressure [bar] ln(k) n-alkanes on NaCaA,2,225,25,275 1/T [K -1 ] n = Langmur n max K p 1+ K p Heat of adsorpton Ads H R ( n) d ln( K ) = d ( 1 ) n T

15 Equlbra of pure gases on SorboNort B3 6, 3 amount adsorbed [mmol/g] 5, 4, 3, 2, 1, Ar at 3 C Ar be 45 C O2 at 3 C O2 be 45 C Kr at 3 C Kr be 45 C Xe at 3 C Xe be 45 C qst [kj/mol] Ar O2 Kr Xe,, 1, 2, 3, 4, Isotherms of O 2, Ar, Kr and Xe on Sorbonort B3 ln p n pressure [bar] vral equaton: = K + B n + C n 2 + D n 3 q St qst R amount adsorbed [mmol/g] Isosterc heat of adsorpton of O 2, Ar, Kr and Xe on Sorbonort B3 ( n) d ln( p) R = d T = T 1 2 ( 1 ) T T2 T 1 n exp ln exp 3 ( K( T1 ) + B( T1 ) n... + D( T1 ) n ) 3 K( T ) + B( T ) n... + D( T ) n ( ) 2 2 2

16 Pressure Swng Adsorpton (PSA) Knowledge of: Isotherms Heat of adsorpton Knetcs Coadsorpton producton Adsorber A regeneraton Adsorber B

17 Dffuson n porous materals Dffuson n pores movng of molecules n pore system from the edge to the center Drvng force s the dfference n chemcal potental Free path of molecules s restrcted by geometry of pores (Knudsen dffuson) Rate of sorpton s a functon of many factors (for example Temperature, geometrcal parameters and transport barrers)

18 Lmt by dffuson / Surface barrer Concentraton profle for dffuson controlled processes Concentraton profle for domnant surface barrers relatve concentraton 1,8,6,4,2 ncrease wth tme 1 dstance from surface relatve concentraton 1,8,6,4,2 ncrease wth tme 1 dstance from surface Both cases are lmts, realty wll be between. In the case of domnant barrers, there exst always equlbrum nsde the partcle No nformaton regardng ntracrystallne dffuson

19 Uptake-curves from measurements of knetcs,25 1 mbar sgnal of balance [g],2,15 1 mbar < 1 mbar, tme [mn] Uptake for the determnaton of knetc parameters

20 Knetc measurements 8 n-butane on NaCaA 1, n-butane on NaCaA sgnal of balance [mg] tme [s] 1-Ψ(t) Ψ(t) calculaton of the Relatve Uptake Ψ() t,8,6,4,2, tme [s] = m ( ) m t t= m m t= t= Relatve Uptakes dfferent adsorpton and desorpton steps under same condtons Adsorpton and desorpton symmetrcal Adsorpton and desorpton curves have an ntersecton at,5

21 Fttng of the dffuson models n-butane on NaCaA n-butane on slcalte-1 1, 1,,8,8 Ψ(t),6,4 Ψ(t),6,4,2,2, tme [s], tme [s] Adsorpton of n-butane on NaCaA at 2 C (3 mbar to 1 mbar) Adsorpton of n-butane on slcalte-1 at 3 C (1 mbar to 15 mbar) D=2, m 2 /s D=3, m 2 /s Non-sothermal dffuson model Isothermal dffuson model

22 Pressure Swng Adsorpton (PSA) producton Adsorber A regeneraton Adsorber B Knowledge of: Isotherms Heat of adsorpton Knetcs Coadsorpton Predcton of Breakthrought Curves

23 Apparatver Aufbau measurement of mxtures Volumetry: Analyss of the gas phase wth a GC Evaluaton of the adsorbed amount by usng mass balances

24 Sorpton of mxture Ar/Kr on SorboNort B3 amount adsorbed [mmol/g] 4 3,5 3 2,5 2 1,5 1,5 exp. total exp. Ar exp. Kr IAST Ar IAST Kr IAST total Kr concentraton n adsorbate phase (xkr) 1,8,6,4,2 exp. IASTcalc.,2,4,6,8 1,2,4,6,8 1 Kr concentraton n gas phase (y Kr ) Kr concentraton n gas phase (y Kr ) Total amount adsorbed and partal amounts for mxtures Ar/Kr on SorboNort B3 Mc Cabe Thele plot for Ar/Kr on SorboNort B3 Co-adsorpton data at 8,6 bar and 3 C Selectvty for Kr: α = 4, at y Kr =,5

25 Sorpton of mxture Ar/Xe on SorboNort B3 amount adsorbed [mmol/g] ,2,4,6,8 1 Xe concentraton of gas phase (y Xe ) IAST total IAST Ar IAST Xe exp. total exp. Ar exp. Xe Xe concentraton n adsorbed phase (xxe) 1,8,6,4,2,2,4,6,8 1 Xe concentraton n gas phase (y Xe ) exp. IAST calc. Total amount adsorbed and partal amounts for mxtures Ar/Xe on SorboNort B3 Mc Cabe Thele plot for Ar/Xe on SorboNort B3 Co-adsorpton data at 8,4 bar and 3 C Selectvty for Xe: α = 31 at y Xe =,1

26 Sorpton of mxture Ar/O 2 on SorboNort B3 amount adsorbed [mmol/g] 1,8 1,6 1,4 1,2 1,8,6,4,2 IAST total IAST O2 IAST Ar exp. total exp. O2 exp. Ar Ar concentraton n adsorbed phase (xar) 1,8,6,4,2 exp. IAST calc.,2,4,6,8 1,2,4,6,8 1 Ar concentraton n gas phase (y Ar ) Ar concentraton of gas phase (y Ar ) Total amount adsorbed and partal amounts for mxtures Ar/O 2 on SorboNort B3 Mc Cabe Thele plot for Ar/O 2 on SorboNort B3 Co-adsorpton data at 8,7 bar and 3 C Selectvty for Ar: α =,95 at y Ar =,1

27 Pressure Swng Adsorpton (PSA) Knowledge of: Isotherms Heat of adsorpton Knetcs Coadsorpton producton Adsorber A regeneraton Adsorber B Predcton of Breakthrought Curves

28 Predcton of breakthrough curves Predctons supports the process engneers wth many nformatons Possble to estmate behavor under dfferent condtons wthout experments Can help to understand complex processes Knetcs Isotherms Feed flow Smulaton models (Quantty) cycle tme, dmenson of adsorbers Coadsorpton data Product qualty

29 Model Equatons Mass Balance C t g, D ax 2 C z g, 2 C + u z g, + C g, u z + ( 1 ε ) ε ρ b q t = p = R T g C g, accumulaton term axal dsperson axal convecton ( flow) mass dffused/adsorbed nto the partcles Mass Transfer Equaton q t q K = K eff, ( q q ) = Fkt( Isotherm) eff = Fkt( Dffuson) Isotherm-Equatons HENRY LAI TOTH q q q = q = max, = q K C max, g, K C g, 1+ K C g, K C n 1/ n ( 1+ ( K C ) ) g, g, wth K = K, H exp RT g

30 Influence of some Parameters 1 1 Breaktrough-Sgnal,8,6,4,2 Henry 1 Henry 2 Henry 3 Breaktrough-Sgnal,8,6,4,2 Transportcoeff. 1 Transportcoeff..5 Transportcoeff tme tme Breaktrough-Sgnal,8,6,4,2 sotherm non-sotherm strong non-sotherm Temperature 294, ,5 sotherm non-sotherm strong non-sotherm tme tme

31 Predcton of breakthrough curves c/c 1,2 1,,8,6,4,2, tme [mn] EXP 2,5% 1bar SIM 2,5% 1bar EXP 5% 1bar SIM 5% 1bar EXP 5% 5 bar SIM 5% 5 bar EXP 5% 2 bar SIM 5% 2 bar Verfcaton of predcton model wth experment

32 Expermental Setup Pressure Controller ( - 65 bar) GC (N 2 ) CO 2 % Component 2 Hydrogen Component 1 IR Analyzer (CO 2, CH 4, CO) Flow Controller 1 ( 3 ml/mn) Flow Controller 2 ( 5 ml/mn) Column Steel (Ø 2.8 cm)

33 Equpment

34 Ternary Mxture CO 2 /CH 4 /H 2 AC CarboTech D 55/2 C PSA sgnal [%vol] CarboTech D 55/2 C PSA: 37.83g / 14.5cm H 2 : 155 ml/mn CO 2 : 35 ml/mn CH 4 : 1 ml/mn 1 bar - Adsorpton 1 st run - 22 C 2 nd run - 25 C 3 rd run - 22 C 4 th run - 23 C sgnal [%vol] CarboTech D 55/2 C PSA: 37.83g / 14.5cm H 2 : 2 ml/mn CO 2 CH 4 1 bar - Desorpton 1 st run - 23 C 2 nd run - 24 C 3 rd run - 22 C 4 th run - 23 C tme [mn] tme [mn]

35 Summary and Outlook Isotherms were gravmetrcally measured and analyzed wth dfferent models. All knetcs have sgnfcant heat effects, whch n the nterpretaton of expermental data must be taken nto account. knetk lmt of gravmetrc system D/r 2 =2*1-2 sek -1 (n-butane on slcalte-1 at 3 C) Smulatons are n good agreement wth experments. Model should be mproved to smulate multcomponent systems wth dfferent sotherm models Applyng IAST on model for calculaton breakthrough-curves Further analyss of the nfluence of the process parameters on the smulatons Expermental runs wth layered beds