Investigation of Mixed Gas Sorption in Lab-Scale Experiment and Evaluation

Transcription

1 Investgaton of Mxed Gas Sorton n Lab-Scale Exerment and Evaluaton Dr. Andreas Möller Chrstan Rechenbach, Robert Eschrch 3P INSTRUMENTS GmbH & Co. KG 8-6- Adsorton Summer School

2 Techncal Necessty: Alcaton of Porous Materals as Adsorbents Fne cleanng of Gases (.e. urfcaton of H, natural gas, bo methane ) Waste ar treatment, resratory rotecton, solvent recovery, removal of ollutants ) Gas searaton (.e. Ar searaton ) Modern and effectve materals should have hgh sorton caactes, hgh selectvtes, and a good knetc erformance. For such alcatons, one must consder gas mxtures and ther sorton roertes n any case.

3 Characterzaton of Adsorbents Nova Touch Sorb HP mxsorb L Bench scale, Plot lants, Industral Plant Number of Samles Alcaton Progress Synthess and Frst Characterzaton Determnaton of Thermodynamc Data Basc Process Desgn, Granulaton of Adsorbents Detaled Process Desgn, Alcaton Chemsts Chemsts, Physcsts Chemcal Engneers Engneers BET Pore Volume Pore Sze Dstrbuton Isotherms Heat of Adsorton Techn. Useable Sorton Caacty Gas Mxtures Selectvtes Selectvtes Knetcs for Process Condtons Cycle Stablty Process Otmzaton Producton 3

4 Characterzaton of Adsorbents Nova Touch Sorb HP mxsorb L Bench scale, Plot lants, Industral Plant Number of Samles Alcaton Progress Synthess and Frst Characterzaton Determnaton of Thermodynamc Data Basc Process Desgn, Granulaton of Adsorbents Detaled Process Desgn, Alcaton Chemsts Chemsts, Physcsts Chemcal Engneers Engneers BET Pore Volume Pore Sze Dstrbuton Isotherms Heat of Adsorton Techn. Useable Sorton Caacty Gas Mxtures Selectvtes Selectvtes Knetcs for Process Condtons Cycle Stablty Process Otmzaton Producton

5 Why are Textural Proertes not enough? Textural Proertes of Adsorbents: BET-Surface Pore Sze Dstrbuton Mcroore Volume Textural roertes allow only lmted qualtatve statements regardng: exected sorton caacty (Mcroore Volume) rough assessment of general sorton roertes from Pore Sze Dstrbutuon Textural roertes do not allow quanttatve statements regardng: sorton affnty selectvty no suffcent nformaton of surface chemstry 5

6 Selectvty and Searaton factor Often dfferent defnton of selectvty (searaton factor)! Thermodynamc selectvty and lmt of selectvty () a Dfference of shae of sotherms and of loadngs mortant [] a CO, CH Y Y CH CO X X CO CH Knetc searaton faktor b Dfference of sorton rates mortant [3] Sorbent selecton arameter of Rege and Yang [] S q q CO CH a CO,CH a CO, CH H H CO CH Y mole rato n gas hase X mole rato n adsorbed hase H Henry constants q dfference n loadng between adsorton and desorton b CO, CH H H CO CH D D CO CH H Henry constants D Dffuson coeffcents [] R.T. Yang, Gas searaton by adsorton rocesses, Imeral College Press, London, 987 [] S.U. Rege, R.T. Yang, Se. Sc. & Technol.,, 36, [3] D.M. Ruthven, S. Farooq, K.S. Knaebel, Pressure Swng Adsorton, Wley-Verlag, New York

7 Mxture Equlbra - Bascs Deendence of artal and total adsorton amounts General: nco, CH total FKT YCO YCH,,, Investgaton along: THE READ LINE Case A n const. FKT THE BLUE LINE Case B n CO CO, CH, total Y Y CH,, total CO, CH Y Y const. FKT CO, CH - - artal loadngs, - total loadng 7

8 Mxture Equlbra - Bascs Tycal resentaton of sorton caactes for bnary mxtures X CO / Case A varable gas comoston CO adsorbed amount / mmol ḡ Case B varable ressure total loadng CO CH Y CO / ressure / bar =const. ( bar), CO,CH on D55-.5 Y=const. (5:5), CO,CH on D55-.5 X-Y-Plot wth statement to the comoston of adsorbed hase at constant ressure N--Plot wth statement to the comoston of amount of adsorbed at constant comoston of the gas hase 8

9 Mxture Equlbra - Bascs Tycal resentaton of sorton caactes for bnary mxtures Case A varable gas comoston adsorbed amount / mmol ḡ total loadng CO CH adsorbed amount / mmol ḡ Case B varable ressure total loadng CO CH Y CO / - =const. ( bar), CO,CH on D ressure / bar Y=const. (5:5), CO,CH on D55-.5 N-Y-Plot wth statement to the artal loadng at constant ressure N--Plot wth statement to the comoston of amount of adsorbed at constant comoston of the gas hase 9

10 Mxture Equlbra - Bascs Relatonsh between loadng mole fracton selectvty. Calculaton of mole fractons of adsorbed hase from artal loadng. Calculaton of mole fracton of gas hase from artal ressures 3. Calculaton of selectvty. Check lausblty wth hel of lmt for selectvty (for IAST-Calculatons) X CO n CO n CO n CH Y CO CO CO CH selectvty a / - 8 E-6 E-5 E- E-3.. ressure / bar Selectvty a Selectvty a -> a CO, CH Y Y CH CO X X CO CH a CO, CH H H CO CH 5% CO,5% CH on NaMSX, IAST wth Toth Lmt of selectvty can be used to check the results of IAST-Calculatons (only for models wth Henry range) Often Lmt of selectvty do not reflect the selectvty for the real searaton rocess, therefore a sngle consderaton s not enough

11 Mxture Equlbra - Bascs Models for mxture data Requrements: Knowledge of ure comonent sotherms Extended langmur-lke equatons [] IAS-Theory [] VS-Model [3] Mult Comonent-Langmur (MCLAI) Mult Comonent-Ss (MCSIPS) Mult Comonent-DSLAI (MCDSLAI) IAST wth Langmur IAST wth Toth IAST wth DSLAI VS-Modell wth Wlson q q m b j x b, x MCSIPS j j A RT n Isotherm( d const. [] R.T. Yang, Gas Searaton by Adsorton Processes, Imeral College Press,987 [] A.L. Myers, J.M. Prausntz, AIChe Journal, 965,, 9 [3] T.W. Cochran, R.L. Kabel, R.P. Danner, AIChe Journal, 3, 985,, 75 n o )

12 Mxture Equlbra - Models Models for mxture data Requrements: Knowledge of ure comonent sotherms Extended langmur-lke equatons IAS-Theory VS-Model Mult Comonent-Langmur (MCLAI) Mult Comonent-Ss (MCSIPS) Mult Comonent-DSLAI (MCDSLAI) IAST wth Langmur IAST wth Toth IAST wth DSLAI VS-Modell wth Wlson q q m b j x b, x MCSIPS j j A RT n Isotherm( n d const. o ) redctve calculatons wth 3P-Sm ossble

13 3 General Soluton Algorthm for IAST RT A d n X Y Y X Nonlnear Equaton System can be solved by Newton Algorthm Formulaton of equaton system Buld u of Jacoban matrx J N f N f f f f ,,, FKTN J Solvng of ln. Equaton system by Gaussan elmnaton Calculate of negatve Functons (as vector),,,,, N N N N Defne startng Values (as vector).,.., FKT FKT Calculate a new vector The whole rocedure wll be reeated tll N N,, = Most Imortant Problem: Fndng of sutable startng values for convergence! Hnt: Testng the soluton by nsertng nto equaton system

14 General Soluton Algorthm for IAST Examle wth Langmur (3 Comonents) Formulaton of equaton system and elmnaton of X Buld u of Jacoban matrx J,,, FKTN J Solvng of ln. Equaton system by Gaussan elmnaton Calculate of negatve Functons (as vector),,,,, N N N N Defne startng Values (as vector) 3 The whole rocedure wll be reeated tll N N,, = Hnt: In case of Langmur sotherm an analytcal soluton exsts: b b n b b n b b n Y Y Y m m m b b n b b n b b n Y Y Y m m m ln ln ln b n b n b n Y Y Y m m m ex ex ex 3 3 m m m n Y n Y n Y

15 Mxture Equlbra - Calculatons Calculatons of mxture data wth 3P-Sm Recommendatons for ure comonents. Fttng of ure comonent data at same temerature for all comonents. All data as table - ressure / bar (mbar) and adsorbed amount / mmol g - 3. All comonents must be ftted wth same sotherm model TYP I: Langmur, SIPS, Toth, DSLangmur, DSLangmurSIPS Ty II: (Freundlch) Ty IV, V: DSLangmurSIPS, (DSLangmur), (SIPS) 5 IUPAC Techncal Reort, Pure Al. Chem. 5; 87(9-),

16 Mxture Equlbra - Calculatons Calculatons of mxture data wth 3P-Sm fttng of ure comonents ) Coy equlbrum data from EXCEL ) Choce of a sutable sotherm model 3) Fttng the Model to get model arameter Examle: CO, CH on NaMSX at C 6

17 Mxture Equlbra - Calculatons Calculatons of mxture data wth 3P-Sm calculaton of mxture data ) Choce of an sotherm model for mxture ) Inut of arameter from ure comonent sotherms 3) Choce of calculaton tye (=const. or Y=const.) The selected mxture model must nclude the ure comonent sotherm model!.e.: wth SIPS only the Multcomonent-SIPS aroach s avalable 7

18 Statc versus Dynamc Methods Statc-volumetrc Method Sorton n closed chamber Measurement of ressure dro Pure comonent sotherms, mxed gas sorton hard to realze Standard characterzaton (BET, Pore volume, ure comonent sotherms) Dynamc Method Sorb HP Sorton n an oen system at constant ressure Tme resolved measurement of effluent gas comoston Manly for mxed gas sorton, ure comonent data only wth some aroaches ossble Techncal rocesses n Labscale Investgatons to techncal relevant arameters (selectvty, sorton knetc, regenerablty, cycle stablty ) mxsorb L 8

19 Measurement Technques Statc Volumetry R.Bazan et al., Adsorton,, 7(), Dosng and mxng of a redefned gas mxture n V by crculaton um Swtch to adsorton chamber V and contnuous mxng by crculaton um Recordng of ressure dro and analyss of gas hase after achevement of equlbrum Calculaton of artal loadng based on mass balance Precalculatons necessary for a desred equlbrum ont 9

20 Measurement Technques Headsace Headsace Method (HS): Secal case of a statc-volumetrc setu Hgher samle throughut as classcal volumetry Prmarly for vaor mxtures sutable Prncle: Regeneraton under N at 5 C (AC) Sometmes reloadng wth comonent (.e. H O) Loadng of HS-Val wth samle and VOC (wth µl- Syrnge) Equlbraton for several days n temered bath Analyss of gas hase va GC and erformng of a mass balance Headsace GC at INC e.v. M.J.G.Lnders et al., AIChE Journal,, 7(8), Vals Precalculatons necessary for a desred equlbrum ont

21 Measurement Technques Dynamc Setu Flow lot of a setu for the dynamc method Flow through the regenerated samle wth a redefned gas mxture Measurement of data at a secfed ressure and gas comoston Advantage over statc volumetry, no recalculatons necessary A.Möller et al., Adsorton, 6, 3(-3),

22 Measurement Technques Overvew Statc-Volumetrc Headsace Method Dynamc Method Closed Chamber Closed Chamber Oen System no carrer gas necessary Sutable for gas mxtures and vaors no carrer gas necessary Manly for vaors carrer gas necessary, deendng on the routne Sutable for gas mxtures and vaors Exermentally comlex Precalculatons necessary Sequenced exerments hard to erform Precalculatons necessary Sequenced exerments hard to erform No recalculatons necessary Sequenced exerments easy to erform Exerments along the Lnes ossble

23 Measurement Technques Overvew Statc-Volumetrc Headsace Method Dynamc Method Closed Chamber Closed Chamber Oen System no carrer gas necessary Sutable for gas mxtures and vaors no carrer gas necessary Manly for vaors carrer gas necessary, deendng on the routne Sutable for gas mxtures and vaors Exermentally comlex Precalculatons necessary Sequenced exerments hard to erform Precalculatons necessary Sequenced exerments hard to erform No recalculatons necessary Sequenced exerments easy to erform Exerments along the Lnes ossble 3

24 Measurement Technques Dynamc Method Balancng of breakthrough exerments rel. breakthrough / % tme-on-stream / s n adsorbed = n n (t)dt n out (t)dt n adsorbed = V n (t) y n(t) V m dt V out (t) y out(t) V m dt Wdely used aroach and smlfcaton for hgh dluted systems: V Out t V t const. In Small changes n concentraton mnmze ths error Hgh dluted systems easer to evaluate

25 Measurement Technques Dynamc Method bnary mxture: CO /He (non-adsorbable carrer gas) Pure comonent equlbra CO /CH (adsorbable carrer gas) Preloadng of samle wth ure CH Incomlete Determnaton of the system (evaluaton mostly smle) Partal loadng for CO (mxture sorton data) ternary mxture: CO /CH /He (non-adsorbable carrer gas) Dslacement of less adsorbed comonent Partal Desorton, Role-U Effects Comlete Determnaton (evaluaton comlex) CO /CH /N (adsorbable carrer gas) Preloadng of samle wth ure N Partal loadng for CO and CH Incomlete ternary mxture data 5

26 Plannng of a Mxture Measurement Calculaton of mxture data desred (Y/N)? Pure comonent sotherms necessary Is a comlete determnaton of the system desred? determnaton of all artal loadngs, dlutng wth Helum-carrer gas (Y/N) Defnton of total flow, concentraton, measurement temerature etc. Samle must be under thermodynamc control (always) Deendng on concentraton range one should consder: Calbraton of sutable analytc technque (always) Check f any aroach s vald,.e. constant gas velocty (always) Samle rearaton and defnton of rearaton condtons Temerature, carrer gas (always) Buld u of a measurement routne ressurzaton, Helum or Adsortve (Helum for comlete determnaton) Evaluaton of the exerment Defnton of measurement task Defnton of measurement condtons Selecton and calbraton of analytcs Measurng and Evaluaton 6

27 Plannng of a Mxture Measurement Calculaton of mxture data desred (Y/N)? Pure comonent sotherms necessary Is a comlete determnaton of the system desred? determnaton of all artal loadngs, dlutng wth Helum-carrer gas (Y/N) Defnton of total flow, concentraton, measurement temerature etc. Samle must be under thermodynamc control (always) Deendng on concentraton range one should consder: Calbraton of sutable analytc technque (always) Check f any aroach s vald,.e. constant gas velocty (always) Samle rearaton and defnton of rearaton condtons Temerature, carrer gas (always) Buld u of a measurement routne ressurzaton, Helum or Adsortve (Helum for comlete determnaton) Evaluaton of the exerment Defnton of measurement task Defnton of measurement condtons Selecton and calbraton of analytcs Measurng and Evaluaton 7

28 Plannng of a Mxture Measurement Calculaton of mxture data desred (Y/N)? Pure comonent sotherms necessary Is a comlete determnaton of the system desred? determnaton of all artal loadngs, dlutng wth Helum-carrer gas (Y/N) Defnton of total flow, concentraton, measurement temerature etc. Samle must be under thermodynamc control (always) Deendng on concentraton range one should consder: Calbraton of sutable analytc technque (always) Check f any aroach s vald,.e. constant gas velocty (always) Samle rearaton and defnton of rearaton condtons Temerature, carrer gas (always) Buld u of a measurement routne ressurzaton, Helum or Adsortve (Helum for comlete determnaton) Evaluaton of the exerment Defnton of measurement task Defnton of measurement condtons Selecton and calbraton of analytcs Measurng and Evaluaton 8

29 Plannng of a Mxture Measurement Calculaton of mxture data desred (Y/N)? Pure comonent sotherms necessary Is a comlete determnaton of the system desred? determnaton of all artal loadngs, dlutng wth Helum-carrer gas (Y/N) Defnton of total flow, concentraton, measurement temerature etc. Samle must be under thermodynamc control (always) Deendng on concentraton range one should consder: Calbraton of sutable analytc technque (always) Check f any aroach s vald,.e. constant gas velocty (always) Samle rearaton and defnton of rearaton condtons Temerature, carrer gas (always) Buld u of a measurement routne ressurzaton, Helum or Adsortve (Helum for comlete determnaton) Evaluaton of the exerment Defnton of measurement task Defnton of measurement condtons Selecton and calbraton of analytcs Measurng and Evaluaton 9

30 Examle of a Measurement Routne Task: Investgaton of a bnary system Actvated Carbon, CO (5%), CH (75%), comlete determnaton at 5 bar. Weghtng the samle and samle rearaton at C, He-flow ml mn - (STP). Defnton of artal ressures:,5 bar CO ; 3,75 bar CH ; 5 bar He; Ʃ bar 3. Gas flows: l mn - (STP) He,,75 l mn - (STP) CH,,5 l mn - (STP) CO. Pressurzaton wth Helum u to bar 5. Start of measurement by smultaneous dosng of CO and CH n Helum 6. Recordng of effluent gas comoston va MS (all comonents!) 7. After breakthrough, regeneraton of samle for determnaton of actvated mass 3

31 Examle of a Measurement Routne Task: Investgaton of a bnary system Actvated Carbon, CO (5%), CH (75%), comlete determnaton at 5 bar Result: Breakthrough curve wth Role-U Effect Includes all artal loadngs Reference on CO =,5 bar and P CH =3,75 bar Mole fracton: y CO =,5; y CH =,75 Helum wll not be consdered! Integraton of areas: n(co ); n(ch ); n(total); a 3

32 An Examle for a Comlete Determned System 5% CO 5% CH n He at C, 5 bar, 5 ml mn - (STP) on D 55/.5 Thermodyn. Model (Mult comonent- SIPS) Y CO =,5 Y CH =,75 P total = bar a Model =3,53 A comlete determned System! Dynamc exerment (determnaton of all artal loadngs) n CO =,86 mmol g - n CH =,7 mmol g - a Exerment =3,63 System s comlete determned, good agreement confrmed deal behavor. 3

33 An Examle for an Incomlete Determned System 5% CO 95% N at C, 5 bar, ml mn - on D 55/.5 Thermodyn. Model (Mult comonent- SIPS) Y CO =,5 Y N =,95 P total =5 bar a Model =5,7 System s not comlete determned! Dynamc Exerment (Determnaton of on artal loadng) n CO =,57 mmol g - n N =not determned a Exerment =not determned System s only ncomlete determned. Model s confrmed by exerment. 33

34 Measurement Technques Dynamc Method Sequence of several breakthrough curves on Actvated Carbon D mole fracton y(co ) / % tme-on-stream t / s Condtons: C, L mn - bar (ressurzaton wth N ) Concentratons: 5 % CO - 8 % CO n N Procedure: Start further breakthroughs after equlbrum before Integraton and summaton results n artal loadng data of CO Volume rato and total ressure defnes the artal ressure of CO Mxed sotherm data of CO n N 3

35 Measurement Technques Dynamc Method Measured artal loadng data for CO on Actvated Carbon D at bar loadng q / mmol g IAST total loadng IAST artal loadng CO IAST artal loadng N ex. CO loadng Dynamc measured data (red) IAST-Model (Ideal Adsorbed Soluton Theory) based on ure comonent sotherms (lnes) Mxture of CO and N shows deal behavor on AC mole fracton y(co ) Determnaton of artal loadng data of CO on AC D by erformng sequentally exerments along constant total ressure. n CO const. FKT Y Y N,, total CO, N 35

36 Measurement Technques Dynamc Method Sequence of several breakthrough curves on Actvated Carbon D Assumton of non-adsorbable Gas,.e. Helum as carrer gas wll lead to ure comonent equlbra. Other, adsorbable gases results n mxture sorton data. mole fracton y(co ) / % tme-on-stream t / s CO /He CO /N loadng q / mmol g -. Sorb HP Toth model dynamc exerment... loadng q / mmol g ressure / bar IAST total loadng IAST artal loadng CO IAST artal loadng N ex. CO loadng mole fracton y(co ) 36

37 Vaor Mxture Measurement Dynamc Method % EtOH,5% H O (arox. 8% RH) n N at 5 C, bar, ml/mn on NaMSX Thermodyn. Model (IAST-DSLAI) Y EtOH =,3 Y HO =,678 P total =.33 bar a Model > Dynamc exerment (determnaton of all artal loadngs) n EtOH = ca. mmol g - n HO =,9 mmol g - a Exerment =not determned (>) Very hgh selectvty of model confrmed by exerment 37

38 Vaor Mxture Measurement Dynamc Method % EtOH,5% H O (arox. 8% RH) n N at 5 C, bar, ml/mn on D 55/.5 Thermodyn. Model (IAST-DSLAISIPS) Y EtOH =,86 Y HO =,7 P total =.35 bar Dynamc exerment (determnaton of all artal loadngs) n EtOH = 3,8 mmol g - n HO = 3, mmol g - a Model =,9 a Exerment =3, Devaton between model and exerment no redcton, exerment necessary! 38

39 Comarable Measurements of Mxture Sorton 5% Proane 5% Proylene n He at 5 C, 5 bar, ml/mn on A, A, A Gas Comoston Y / Proylene Proane Gas Comoston Y / Proylene Proane Gas Comoston Y / Proylene Proane. 5 5 tme / mn Samle: A. 5 5 tme / mn Samle: A. 5 5 tme / mn Samle: A3 Y Proane =,5 Y Proylene =,75 n Proane =,3 mmol g - n Proylene =,6 mmol g - a Proylene =,67 Y Proane =,5 Y Proylene =,75 n Proane =, mmol g - n Proylene =,7 mmol g - a Proylene =,83 Y Proane =,5 Y Proylene =,75 n Proane = ca. mmol g - n Proylene =, mmol g - a Proylene = not determned (>) Selectvty Statements on selectvty also ossble wthout modelng from ure comonent data Determnaton of sorton caactes and selectvtes, recordng of knetc 39

40 Relevance for materals / scence and roducton Assessment of orous materals R&D of talor made materals for certan searaton ssues Evaluaton of Influence of some secondary comonents Relevance for engneerng / Process desgn Modelng and Calculaton of fxed bed adsorbers Determnaton of Knetcs (Lnear drvng force constants) Calculaton of breakthrough curves, uscalng by modelng Calculaton of PSA and TSA rocesses Zeolte for gas urfcaton Source: Process gas urfcaton lant source

41 Relevance for materals / scence and roducton Assessment of orous materals R&D of talor made materals for certan searaton ssues Evaluaton of Influence of some secondary comonents Relevance for engneerng / Process desgn Modelng and Calculaton of fxed bed adsorbers Determnaton of Knetcs (Lnear drvng force constants) Calculaton of breakthrough curves, uscalng by modelng Calculaton of PSA and TSA rocesses Zeolte for gas urfcaton Source: Process gas urfcaton lant source

42 Inut Parameters Isotherms Knetcs Heat of adsorton and heat caactes Co-adsorton Adsorber dmensons Smulaton model Heat transfer Feed flow, Feed ressure Product urty Cycle duraton, ressure range Red: roertes of adsorbent/adsortve system Black: roertes of adsorber and adsorber wall

43 Knetc consderatons - Mass Transfer coeffcent kldf Pore Dffuson Convecton, Dffuson Flm Dffuson Adsorbate Adsortve Adsorbent Convecton, Dffuson Adsorton LDF concentraton c loadng q KNUDSEN Dffuson Surface Dffuson Convecton, Dffuson Pore Flm Dffuson Free Dffuson Smlfcaton Effectve Inner Mass Transfer, Lnear Drvng Force (LDF) Adsorton dstance r 3

44 Mass Balance LDF aroach Equaton for velocty / overall mass balance (sothermal) * A.M. Rbero et. al, Chem. Eng. Sc. 63 (8) * D.M. Ruthven, Prncles of Adsorton (98) * M.S. Shafeeyan et. al, Chem. Eng. Res. Des. 9 () Energy Balances wall to envronment accumulaton generaton convecton transfer to wall dserson accumulaton dserson convecton,,,, z u C z C u z C Dax t q t C g g g Part g w g w g g g g g g art g n art T T d h z u cg T z T cg u t T cg cs z T t q M H gas to wall accumulaton Env w g wl w w w g w w T T U t T cw T T h a a LDF q q k t q * Isotherms f q * Change by adsorton t t q M RT z u n art Change by comresson

45 adsorbed amount / mmol g - adsorbed amount / mmol ḡ Relacement effects CO sotherms on D 55/.5 ressure / bar CH at C CH at C CH at 6 C SIPS 5 5 ressure / bar CO at C CO at C CO at 6 C SIPS CH sotherms on D 55/.5 Inut ure comonent Isotherms Fttng k LDF Fttng Heat Transfer Coeff. adsorbed amount / mmol g - Gas Comoston Y / - CO /CH mxture sotherms on D 55/ n total MCSIPS n CO MCSIPS n CH MCSIPS CH exerment CO exerment 3 5 ressure / bar Breakthrough of a mxture CO /CH n He CH CO calculated curves. 5 5 tme / mn 5% CO 5% CH n He at C, 5 bar, 5 ml/mn on D 55/.5 5

46 Relacement effects Temerature rofles Use of ntegral heat of adsorton wth Ss model (from sotherms): q K q s, q K max,, K t n t K j c j j c Q ex R T T Q (equvalent to H Q=,5 ) Q CO : 5.9 kj mol - Q CH :.9 kj mol - T ex T max, qmax,, t t T a T, j Fttng Heat Transfer Coeff. h w : ~ 3 W m - K - (Gas, Fxed Bed/Wall) U g : ~ W m - K - (Wall/Lqud) Inut Q n energy balance temerature / C Temerature rofles along the fxed bed tme / mn T (3 mm) T (5 mm) calculated curves 5% CO 5% CH n He at C, 5 bar, 5 ml/mn on D 55/.5 CH nduced hgher temerature effect Model can descrbe temerature rofles qualtatvely Underestmaton of temerature eaks Exerment shows mostly sharer temerature rofles dfferences due to smlfcaton of no radal gradents radal gradents n exerment exected due to external lqud coolng

47 Examle: CO Adsorton on D55/.5 n N -Carrer Gas amount of CO / Vol.% mn ADS tme / mn DES CO Observatons: ) Desorton curve flatter than Adsorton curve ) Desorton tme hgher than Adsorton tme 3) Adsorton tme 5.78 mn (c out <. %) Questons concernng: ) Knetc arameter (k LDF ) ) Total ressure durng each ste 3) Adsorton/Desorton tmes Adsorton: 5% CO n N at C, 5 bar, ml/mn on D 55/.5 ) Purge flow durng Desorton Desorton: Purgng wth ml/mn N at C, 5 bar 7

48 Regeneraton / PSA Gas Comoston Y / -.5 CO calculated curves mn tme / mn 5% CO 95% N at C, 5 bar, ml/mn on D 55/.5 Model after Fttng Isotherms (MCSIPS) Knetc arameter (k LDF ) Heat Transfer Parameter Model can consder slower Desorton due to curved sotherm Parameter from Exerment: Adsorton tme 5.78 mn Adsorton ressure 5 bar Feed Flow ml/mn Purge Flow ml/mn ure N General Requrements for PSA: Purge Flow 5 ml/mn ure N Desorton n counter current flow Max. CO content n roduct % Queston concernng: ) Desorton ressure? 8

49 Regeneraton / PSA Cycle tmes for modelng: Adsorton tme 5.78 mn Desorton tme 5.3 mn Calculatng 5 Cycles Cycle tmes for Exerment: Adsorton tme bar Blow Down tme ~.5 mn Desorton tme.75 mn Pressurzaton to.6 bar wth N Pressurzaton from.6 bar to 5 bar wth Feed Measurement of 5 cycles CO / Vol.% Calculatons wth DES = bar Predctons by modelng: Regeneraton condtons not strong enough CO murty n effluent flow ncreases from cycle to cycle to ~ 3 % tme / mn 9

50 Regeneraton / PSA Cycle tmes for modelng: Adsorton tme 5.78 mn Desorton tme 5.3 mn Calculatng 5 Cycles Cycle tmes for Exerment: Adsorton tme bar Blow Down tme ~.5 mn Desorton tme.75 mn Pressurzaton to.6 bar wth N Pressurzaton from.6 bar to 5 bar wth Feed Measurement of 5 cycles CO / Vol.% Calculatons wth DES = bar Predctons by modelng: Regeneraton condtons not strong enough CO murty n effluent flow ncreases from cycle to cycle to ~ 3 % tme / mn Predctons were confrmed by exerment 5

51 Regeneraton / VPSA Cycle tmes for modelng: Cycle tmes for Exerment: Adsorton tme 5.78 mn Desorton tme 5.3 mn Calculatng 5 Cycles Adsorton tme bar Blow Down tme ~.5 mn Desorton tme.75 mn Pressurzaton to.6 bar wth N Pressurzaton from.6 bar to 5 bar wth Feed Measurement of 5 cycles CO / Vol. % Calculatons wth DES =.5 bar Predctons by modelng: Regeneraton condtons good enough CO murty n effluent flow ncreases from cycle to cycle, but stll below target (<%) tme / mn 5

52 Regeneraton / VPSA Cycle tmes for modelng: Cycle tmes for Exerment: Adsorton tme 5.78 mn Desorton tme 5.3 mn Calculatng 5 Cycles Adsorton tme bar Blow Down tme ~.5 mn Desorton tme.75 mn Pressurzaton to.6 bar wth N Pressurzaton from.6 bar to 5 bar wth Feed Measurement of 5 cycles CO / Vol. % Calculatons wth DES =.5 bar Predctons by modelng: Regeneraton condtons good enough CO murty n effluent flow ncreases from cycle to cycle, but stll below target (<%) tme / mn Predctons were confrmed by exerment 5

53 Regeneraton / VPSA Cycle tmes for modelng: Adsorton tme 5.78 mn Desorton tme 5.3 mn Calculatng 5 Cycles Cycle tmes for Exerment: Adsorton tme bar Blow Down tme ~.5 mn Desorton tme.75 mn Pressurzaton to.6 bar wth N Pressurzaton from.6 bar to 5 bar wth Feed Measurement of 5 cycles But: modelng dvers from exerment! model CO / Vol. %..8 Cycle Stes n modelng strong smlfed Varatons exerment from model manly n desorton art ex Modelng can hel to reduce exermental effort fnal evaluaton only by exerment! tme / mn 53

54 C 3 H 8 removal from CH (artal ressure range. bar and.5 bar) Selecton of actvated carbon wth dfferent BET-Surfaces, but from same raw materal AC BET ~8 m /g AC BET ~3 m /g CH sotherms on AC and AC at C C 3 H 8 sotherms on AC and AC at C adsorbed amount / mmol g ressure / bar AC AC SIPS adsorbed adsorbed amount amount /mmol /mmol g ḡ E ressure / bar / bar Often AC wth hgher BET wll be selected by user whch s not always the best decson! accordng to sotherms AC s better for low C 3 H 8 concentratons for hgh C 3 H 8 concentratons AC s better 5 AC AC SIPS AC AC SIPS

55 C 3 H 8 removal from CH (artal ressure range. bar and.5 bar) Selecton of actvated carbon wth dfferent BET-Surfaces, but from same raw materal AC BET ~8 m /g AC BET ~3 m /g. breakthrough of % C 3 H 8 n CH at C, bar 5 breakthrough of 5% C 3 H 8 n CH at C, bar.8 C 3 H 8 / Vol. %.6. AC AC smulaton C 3 H 8 / Vol. % 3 AC AC smulaton secfc tme / mn g secfc tme / mn g - Breakthrough exerments and smulatons very senstve for low concentratons! Observatons made from sotherms were confrmed by dynamc exerments and calculatons 55

56 Calculaton of Constant Pattern Profles For favored sotherms (Tye I-Isotherms) a Constant Pattern Behavor can occur Shae of breakthrough wll not change for longer elongaton tmes or adsorber heghts, resectvely Based on comensaton of flattenng and rsng effects Heght for Constant Pattern = f(shae of Isotherm, Dserson, Knetcs) CO / Vol.% 5 3 Exerment ( cm) calculated curve Sloe for C/C =.5 3 tme / mn 5% CO n He at C, 5 bar, ml/mn on D 55/.5 CO /Vol.% tme / mn 5 cm cm cm 3 cm cm 6 cm 8 cm sloes Sloe at C/C = Sloe at C/C = heght of fxed bed / cm Exerment carred out at cm, smulatons were erformed for dfferent heghts Sloes at C/C =.5 were used to evaluate steeness of breakthrough curves Constant Pattern Behavor can be exect above cm bed heght 56

57 Conclusons Equlbra of mxtures and selectvtes are mortant for alcatons Knowledge of such data are hghly valuable and of great nterest however much more dffcult to measure There s a lack of data n lterature Mxture equlbra can not calculated by textural roertes but artal redctve from ure comonent sotherms based on classcal thermodynamc Models. Predctons have some lmts! Number of comonents, vaors, non-deal systems, exerments are mandatory Mxture Models necessary for calculatons of dynamc rocesses 57

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