University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Experimental Methods for Single- and Multi-Component Gas Adsorption Equilibria
J.U. Keller 1), N. Iossifova 1), W. Zimmermann 1), F. Dreisbach 2), R. Staudt 3)
1)Inst. Fluid- and Thermodynamics, University of Siegen,D-57068 Siegen, [email protected]
2)Rubotherm Präzisionsmesstechnik GmbHUniversitätsstr. 142, 44799 Bochum, Germany
3)Center of Non-Classical Chemistry, University of LeipzigPermoserstr. 1504318 Leipzig, Germany
Introduction
1. Volumetry / Manometry
2. Gravimetry
3. Oscillometry
4. Calorimetry
5. Impedance Spectroscopy
Hybrid Measurements
6. Volumetry / Gravimetry
7. Densimetry / Gravimetry
8. Densimetry / Volumetry
9. Manometry / Impedance Spec.
10. Conclusions
4 PB-1
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Adsorptive 1
Adsorptive 2Adsorption(exothermic) Desorption
(endothermic)
Adsorbent
Adsorbate
Adsorption
4 PB-2
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Gas Flow Porosimeter (He, N2, BET, 77 K)
1 Sample / Sorbent
2 Dewar vessel (N2, 77 K)
3 Mixing chamber
4 Thermal diffusivity detector (a)
5 Sorptive gas flow (original)
6 Reduced gas flow (changed)
7 Data display system (Ua)
4 PB-3
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Experimental setup for volumetric-chromatographicmeasurements of multi-component gas adsorption equilibria
4 PB -4
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Mass balances
Total mass (i)
Adsorptive’s mass (i)
* fi i im m m i 1...N
* * f * * *i i 1 N SVm w T,p ,w ...w V
f f Si i SV ACm V V V
(1)
(2)
(3)
f Si i i(1 3) : m V
*i i i SV i ACV V
f fi i N iw T,p,w,...w , w : GC
S SHe iV V m ... Gibbs excess mass
(4)
Volumetry / Chromatography (Closed Systems)
4 PB-4A
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Adsorption equilibria of a CH4-CO2-N2 gas mixture on activated carbon ACR1. Data correlation:2-sites LAI
4 PB-5
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Gas – Solid – Adsorption Equilibria :Volumetric – Chromatographic Analysis (N1)
4 PB -6
PCiA
GC
Impedance Analyzer
N2Ar
CO2CH4
FLOW
RATES
Gas Chromatograph
AnalysisFormulation
1 2 3 TF T
Sorbent MaterialSorbate
Sorptive Gas
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Volumetry / Chromatography (Open Systems)
* fi i i
*i i in i out
i in i in i out i out
f fi i inf f
f * sHe
N
in CG k ink
n n n , i ...N
n n n dt
y n y n dt
n y npV n TV V V
n n n
0
0
Molar Balances 1
Total Amount (i)
Adsorptive's Amount (i)
Geometry, He-Volume
k in k in in
N
out CG k out k out k out outk
, y n n
n n n , y n n
4 PB-6A
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Experimental setup for gravimetric-chromatographic measurements of multicomponent gas adsorption equilibria
V
T
p
Gas Chromatograph
Adsorption Chamber
Microbalance
CirculationPump
GasSupply
Thermostat
VacuumPump
AC
Gas Sample( yi, wi )f f
( yi, wi )* *
SorbentMaterial
Ballast
4 PB-7
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Gravimetry / Chromatography (N 1)
* f a
Nf f f f f
i ii
sAC Hef
f fN
a * * f fi i i
sAC Hea *
i i
m m m
m M n y M n
p V Vn
R T Z p,T, y ...y
m w m w m
p V V: m w
R T
1
Total mass of gas supplied to system:
Sorptive mass / mole number:
Mass of component i=1...N adsorbed:
1
2
3
1 4
sAC Hef f f
i
p V VM w M
Z R T Z
a f sHe
fa s
HesAC He
m V
mm V AV V
Microbalance:
4
4
4 PB-7A
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
p
VacuumPump
OscillatingDisk
Filled with Adsorbens
Gas Supply
Laser and Diodes
PC
Mirror
SorptiveGas
Reflected Beam
Front View Top View
T
g
1
2
p
VacuumPump
OscillatingDisk
Filled with Adsorbens
Gas Supply
Laser and Diodes
PC
Mirror
SorptiveGas
Reflected Beam
Front View Top View
T
g
1
2
Experimental Setup for oscillometric measurements of gas adsorption equilibriausing a rotational pendulum.
Rotational pendulum for measurements of gasadsorption equilibria by observing slow dampedoscillations. Height of instrument: 1.5 m.
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
220 0
s 2EE
1m 1m 1
220 02
EEs 0 0
* *
1 11m
m 1
sIdeal Pendulum m ,m * sPhysical Pendulum m ,m ,m
* * *, ... empty pendulum m , vacuum
* s0 0, ... pendulum and adsorbent m ,m , vacuum
* sE E, ... pendulum, adsorbent, adsorbate m ,m ,m , gas
Oscillometric Measurements of Gas Adsorption Equilibria. Theory
4 PB-8A
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Rotational pendulum and ring slit filled with polycarbonate pellets
4 PB-9
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Swelling and sorption isotherm of polycarbonate / CO2 at 293 K
p [MPa]0 1 2 3 4 5 6 7
Vas
/ (m
a +ms )
[cm
3 /g]
0.80
0.85
0.90
0.95
1.00
1.05
m
g/g]
ma [m
g/g]
-50
0
50
100
150
200
250 Vas / (ma+ms)grav
osc
ma
4 PB-10
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Schematic diagram of a sensorgas calorimeter (SGC)
Sensor gas calorimeter (SGC) forsimultaneous measurements of adsorption isotherms and enthalpies. © IFT, University of Siegen, 2003.
Air Thermostat
4 PB -11
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Calibration experiments in the SGC 0.5J to 5JSensor gas N2 (1.6bar), T=298K, =10s
Ohm’s heat release (red lines) Pressure signal (blue lines)
0
20
40
60
80
100
120
0 100 200 300 400 500 600 700 800Time [s]
Diff
eren
ce P
ress
ure
[Pa]
0
50
100
150
200
250
300
350
400
450
500
Ele
ctri
cal
Pow
er [
mW
]
4 PB-12
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
0
20
40
60
80
100
120
0 200 400 600 800Timescale for Difference Pressure Axis [s]
Diff
eren
ce P
ress
ure
p(t)
[Pa]
0
50
100
150
200
250
300
350
400
450
5000 20 40 60 80 100
Timescale for Electrical Power Axis [s]
Ele
ctric
al P
ower
[m
W]
Difference PressureElectrical Power
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6
Ohm's Heat Q [J]
Red
uced
Pea
kare
a A
* [k
Pa
s]
2
0 525 6 211
0 9993
kPasA A* . kPas . QJ
R .
CorrelationPeak Area (A / Pas)Qhm’s heat (Q / J)
Calibration experiments of the SGC.Ohm’s heat : Q= (0.5, 1.0 ... 5.0)JSensor gas: N2, p*=0.15MPa, T*=298K
4 PB-12A
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Differential and integral heat of adsorption for activated carbon AC BAX 1500 / n-butane (C4H10) at 298K
0 1 2 3 4 5 60
10
20
30
40
50
60
70
80
90
100
Heat of Condensation for n-butane (20,95 kJ/mol)
Mesured differential heat of adsorption Differenciated from integral heat of adsorption
Diff
eren
tial h
eat o
f ads
orpt
ion
[kJ/
mol
e]
n-butane ads. [mmole/g]
0
50
100
150
200
250
300
350
400
Measurend integral heat of adsorption Interpolated integral heat of adsorption
Inte
gral
hea
t of a
dsor
ptio
n [J
/g]
4 PB-13
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Vacuum Pump
Gas Supply
p*
T
p
AdsorptionChamber
Gas Circulation Pump
T*
Storage Vessel
V*
Capacitor
Gas Chromatograph
mS
ImpedanceAnalyzer
IA
Sorbent
Heasfas**
MG VV,)T,p(VVmmM,V
MGDE m)T,p(DE
4 PB-14
Experimental setup for volumetric-dielectric measurements
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
f/ kHz2000 4000 6000 8000 10000 12000 1400
C/ F
5.1e-12
5.2e-12
5.3e-12
5.4e-12
5.5e-12
5.6e-12 Vakuum 0.01 MPa0.1961 MPa0.9916 MPa1.5001 MPa1.9924 MPa
Impedance spectra of CO2 on zeolite (DAY), T=298K
4 PB-15
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Cole-Cole-Plot for system H2S / MS 13X, T=298K
Re 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Im
0.0
0.2
0.4
0.6
Vacuum0.01 MPa0.03 MPa0.1 MPa0.2 MPa0.4 MPa
4 PB-16
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Cole-Cole-Plot for system CO / MS 13X, T=298K
Re 2.5 3.0 3.5 4.0 4.5
Im
0.0
0.2
0.4
0.6
Vacuum0.6 MPa1.9 MPa
12 MPa3.9 MPa
4 PB-17
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Uptake curves of H2S on MS 13X, T=298K
4 PB-18
Time [h]0.0 0.2 0.4 0.6 0.8 1.0
Rel
ativ
e up
take
0
1
2
3
4
5
6Impedance spectroscopyGravimetry
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Gibbs excess amount of adsorbed (nGE) [mmol/g]0 1 2 3 4 5
Cap
acita
nce
(C
) [p
F]
0.0
0.5
1.0
1.5
2.0
2.5
N2 / Pellets AC-20
CO / Pellets AC-20T = 298 K, = 4 MHz
CH4 / Pellets AC-20
a
Change of the dielectric capacity (C) of AC-20 pellets upon adsorption of gases (N2, CH4, CO) at 298 K, = 4MHz. Gas pressures (p 4MPa).
4 PB-19
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
64.0
64.1
64.2
64.3
64.4
64.5
64.6
64.7
64.8
64.9
65.0
360 380 400 420 440 460 480Time [s]
Cap
acita
nce
[pF]
25
50
75
100
125
Pre
ssur
e [k
Pa]
Zeolite: MS Na13XFrequency: 10 MHzCycle Time: 30 s
Capacitance
Pressure
Combined manometric (p) and dielectric (r) measurements of ad- and desorption of N2 on MSNa13X (UOP) at 293K.
4 PB-20
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Gas Mixture SorptionHybrid Measurement Methods
Method Material Physics V G O SP CH D C Volumetry (V) Extensivity ++ + 0 ++ ++ 0
Gravimetry (G) Gravity 2 + 0 + + 0
Oscillometry (O) Inertia 1, V 1, V 0 0 0 0
Spectroscopy (SP) Electric Changes 1 1
Chromatography (CH) Molecules N N (N)
Densimetry (D) Extensivity 2 2 1, V
Calorimetry (C) Thermal Inertia 1 1 1
4 PB-21
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Experimental Setup for volumetric-gravimetric measurements of binary coadsorption equilibria (M1M2)
4 PB-22
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
*i
sf 0i is i 1,2mm m 1 m
m
Mass balances
f fas 1 2
1 2 * fm mm m VV V
Micro-balance equation
f f1 2
1 2
* fm mM M
p V V
ZR T
Adsorptive’s equation of state
sf f f as0
1 2 1 2 smm , m , m , m ... V V 1 Vm
Volumetric-Gravimetric Measurements of Binary Coadsorption Equilibria (Theory)
1 2M M
4 PB-23
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Schematic diagram of a volumetric-gravimetric-chromatographic installation with magnetic suspension balance for coadsorption measurements (N 1)
4 PB-24
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
to balance connection
coupling housingthermostat
pressure measurement
measuring fluid
measuring cell
thermostat
temperature measurement
measuring fluid
measuring fluid
sample (adsorbent)
electromagnet
suspension magnet
measuring load decoupling
Magnet suspension balance for sorption measurements (Rubotherm, Bochum, Germany)
4 PB-25
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06 4 PB-26
Magnetic Suspension Balance for Simultaneous Sorption and Density Measurements (Rubotherm, Bochum, Germany)
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Coadsorption equilibria of methane/nitrogen gas mixtures on activated carbon (Norit R1). Data correlation: 2 sites LAI.
4 PB-27
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Installation for Densimetric-Gravimetric Measurements (DGMs) of Binary Coadsorption Equilibria of Premixed Gases (y1, y2)* *
4 PB-28
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Mass balances
Total gas mass supplied
Sorptive gas masses
a * fi i im m m i 1,2 (1)
(2)
(2A)
(3)
(4)
(5)
(6)
* * * a a f f1 2 1 2 1 2m m m m m m m
* f *m V * * *i im w m
* asf f1 2
1 2 i
p V Vm mM M R T Z p,T, w
a * f * si i 1iGE i He
i i 1 i
M p Mm m V VM M R T Z p,T, w
as sHeV V(1, 2A, 3, 4)
Densimetric-Gravimetric Measurements (DGMs) of Coadsorption Equilibria (Theory)
f f f * as1 2m m V V
4 PB-29
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06First Instrument MSB (3)
First performance of DGMs using a MSB (3)on 1998-02-11 in Lab PB-A0126 of IFT/USI
4 PB-30
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Diagram CO2/CH4
2 4
i i
2 4 CO CH
i i 2 4
Coadsorption equilibria of CO / CH at T 293K, y 20.4%mol, y 79.6%mol
on AC D47 /3. Correlation by GAI : n n (bp) 1 (bp) , i CO , CH
4 PB-31
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Installation for Densimetric-Volumetric Measurements (DVMs) of Binary Coadsorption Equilibria of Premixed Gases y1, y2.* *
4 PB-32
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Mass balances a * fi i im m m
EOS
i 1,2 (1)
(2)
(3)
(4)
(5)
(6)
* ** i SVi i*
y p Vm M
R T Z * *
iZ Z p ,T, y
Sorptive gas massesf f1 2(m ,m )
f f f * as1 2m m V V
fi
i f f1 2
mw
m m
i 1,2
as sHeV V
a * f * si i 1iGE i He
i i 1 i
M p Mm m V VM M R T Z p,T, w
(1 – 4)
Densimetric-Volumetric Measurements (DGMs) of Coadsorption Equilibria (Theory).
4 PB-33
* asf f1 2
1 2 i
p V Vm mM M R T Z p,T, w
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Photo automated MSB
Automated MSB (2) (Rubotherm AG, Bochum) for Densimetric-Volumetric Measurements (DVMs) of binary coadsorption equilibria
4 PB-34
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Comparison of experimental pros and cons of densimetric-gravimetricmeasurements (DGMs) and densimetric-volumetric measurements (DVMs)of binary gas adsorption equilibria without analyzing the sorptive phase.
4 PB-35
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Vacuum Pump
Gas supply
p*
RotationalPendulum
T
p
AdsorptionChamber
Gas Circulation Pump
T*
Storage Vessel
V*V
Gaschromatograph
Experimental Setup for oscillometric-volumetric measurementsof gas sorption equilibria in swelling materials.
4 PB-36
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Vacuum Pump
T
Gas supply
Microbalance
Sorption Chamber
T
ppRotationalPendulum
SorptionChamber
Gas Circulation Pump
mPolymerSorbent
Experimental Setup for oscillometric-gravimetric measurementsof gas sorption equilibria in swelling materials.
4 PB-37
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Volumetric-gravimetric-oscillometric method (N=2).Co(ad)sorption measurements in swelling sorbent materials (polymers) without using a gas chromatograph.
4 PB-38
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
p [MPa]0 1 2 3 4 5 6 7
V [c
m3 /g
]
0.80
0.85
0.90
0.95
1.00
1.05
1.10
V 308 KV 318 KFit
V = 0.0035 p + 0.86
V = 0.0022 p + 0.86
p [MPa]0 1 2 3 4 5 6 7
m [m
g/g]
0
20
40
60
80
100
120
140
160
m 308 Km 318 KDual Modus
Swelling isotherms of polycarbonate/CO2at T = 308 K and T = 318 K.
4 PB-39
Sorption isotherms of polycarbonate/CO2at T = 308 K and T = 318 K.
University of Siegen Institute of Fluid- & ThermodynamicsJürgen U. KELLER 06
Measurement Methods for Gas Adsorption Equilibria
Pure Gas MethodVolumetry/Manometry
GravimetryOscillometryDielectric Permittivity
Gas Mixtures (N=2)Volumetric-Densimetric M.(2-sites Magnetic Balance)
Gas Mixtures (N>2)Volumetric/Gas Phase Analysis
PurposeCharacterization of porous solids
Equilibria, Kinetics, Gas Density, Process Cont.Swelling MaterialIndustrial Process Control
Equilibria, Process Control
Process Design
Ref:J.U. Keller, R. Staudt, Gas Adsorption Equilibria, Springer, New York, 2004.
4 PB-40
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