university of siegen prof. dr. sc. techn. jürgen u. keller ... · pdf filejürgen u....

University of SiegenInstitute of Fluid- & Thermodynamics

Prof. Dr. sc. techn. Jürgen U. KELLER

Measurement Methods for Single- and

Multi-Component Gas Adsorption Equilibria

JUERGEN U. KELLER, FRIEDER DREISBACH1), NADIA IOSSIFOVA, MARC SEELBACH,

WOLFGANG ZIMMERMANN AND REINER STAUDT2)

Inst. Fluid- and Thermodynamics, University of Siegen, D-57068 Siegen, Germany1)Rubotherm GmbH, Bochum, Germany

2)Inst. Non-Classical Chemistry, University of Leipzig, Leipzig, Germany

[email protected], 1)[email protected], 2)[email protected]

1. Volumetry / Manometry and Densimetry

2. Gravimetry and Densimetry

3. Oscillometry

4. Impedance Spectroscopy

5. Calorimetry and Volumetry

6. Calorimetry and Spectroscopy

Acknowledgements



Volumetry/Manometry and Densimetry

94,22547 g

Gas SupplySystem

Microbalance

Thermostat

T

MagneticSuspension

Thermometer

PermanentMagnet Manometer

SorbentSinker

AdsorptionChamber

VAC

VacuumPump

Gas CirculationPump

T p

StorageVessel 1

StorageVessel 2 T

Instrument for volumetric-densimetric measurements of binary

coadsorption equilibria of gas mixtures on porous solids without

using a gas chromatograph. The sorptive gas prepared in the

system is assumed to be a binary mixture with known initial molar

concentrations (y*1, y*2). © IFT University of Siegen, 2002.



DVMs / Theory

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

* asf f1 2

1 2 i

p V Vm m

M M R T Z p,T, w

fi

i f f1 2

mw

m mi 1, 2

as sHeV V

a * f * si i 1iGE i He

i i 1 i

M p Mm m V V

M M R T Z p,T, w

(1 – 4)



Installation for DGMs

of Binary Coadsorption

Equilibria of Premixed

Gases (y1, y2)* *

Schematic Diagram DGMs



First performance of DGMs using a MSB (3)

on 1998-02-11 in Lab PB-A0126 of IFT/USI

First Instrument MSB (3)



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 m

M M R T Z p,T, w

f f f * as1 2m m V V

a * f * si i 1iGE i He

i i 1 i

M p Mm m V V

M M R T Z p,T, w

as sHeV V(1, 2A, 3, 4)

DGMs / Theory



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

Diagram CO2/CH4

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0.0 0.3 0.6 0.9 1.2 1.5

Pressure p [MPa]

nC

O2, n

tot =

nC

O2 +

nC

H4 [

mm

ol/g

]

ntot = nCO2 + nCH4

nCO2

yfCO2 : y

fCH4 = 0.204 : 0.796

T = 293 K

AC D 47/3



Vacuum Pump

T

Gas supply

Microbalance

Sorption Chamber

T

ppRotational

Pendulum

Sorption

Chamber

Gas Circulation Pump

m

Polymer

Sorbent

Experimental setup for oscillometric-gravimetric measurements

Schematic Diagram OVMs



220 0

s 2EE

1m1

m 1

220 02

EEs

0 0* *

11

1m

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

Theory OscillometricMs



Ring slit of rotational pendulum filled with polycarbonate pellets

Photo ring slit of rot. pendulum



Swelling and sorption isotherm of polycarbonate / CO2 at 293 K

Swelling and sorption isotherms of PC/CO2

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

mg/g

]

ma [

mg/g

]

-50

0

50

100

150

200

250 Vas

/ (ma+m

s)

grav

osc

ma



Vacuum Pump

Gas Supply

p*

T

p

Adsorption

Chamber

Gas Circulation Pump

T*

Storage Vessel

V*

Capacitor

Gas Chromatograph

mS

Impedance

Analyzer

IA

Sorbent

Heasfas**

MG VV,)T,p(VVmmM,V

MGDE m)T,p(DE

Experimental setup for volumetric-dielectric measurements

Schematic Diagram Vol-Diel-Ms



Impedance spectra of CO2 on zeolite (DAY), T=298K

Impedanc Spectra (DAY/CO2)

f/ kHz

2000 4000 6000 8000 10000 12000 14000

C/

F

5.1e-12

5.2e-12

5.3e-12

5.4e-12

5.5e-12

5.6e-12Vakuum

0.01 MPa

0.1961 MPa

0.9916 MPa

1.5001 MPa

1.9924 MPa



Uptake curves of H2S on MS 13X, T=298K

Uptake Curves MS13X/H2S

Time [h]

0.0 0.2 0.4 0.6 0.8 1.0

Rela

tive u

pta

ke

0

1

2

3

4

5

6

Impedance spectroscopy

Gravimetry



Schematic diagram of a

Sensor Gas Calorimeter (SGC)

Schematic Diagram SGC



Calibration experiments in the SGC 0.5J to 5J

Sensor gas N2 (1.6bar), T=298K, =10s

Ohm’s heat release (red lines) Pressure signal (blue lines)

0

20

40

60

80

100

120

0 100 200 300 400 500 600 700 800

Time [s]

Dif

fere

nce

P

ress

ure

[P

a]

0

50

100

150

200

250

300

350

400

450

500

Ele

ctri

cal P

ow

er

[m

W]

Calibration SGC



Heat of adsorption for CO2 / Na13X, T=298K

0 1 2 3 4 5

10

20

30

40

50

60

70

Heat of Condensation for CO2 (5,25 kJ/mol)

Differental heat of adsorption

Derivative of polynomial interpolation

of the integral heat of adsorption

Dif

fere

nti

al

hea

t o

f a

dso

rpti

on

[k

J/m

ol]

CO2 ads. [mmol/g]

0

20

40

60

80

100

120

140

160

180

200 Integral heat of adsorption

Polynomal Interpolation

In

tegra

l h

eat

of

ad

sorp

tion

[J

/g]

Heat of adsorption Na13X/CO2



Schematics of combined

calorimetric-dieletric-volumetric

gas adsorption measurements

Schematic Diagram GSC with Capacitor

12.33 1000.0 6.14

Impedance Analyzer

Capacitor



Calculation of absolute adsorbed masses from DE-C-measurements

0

Hh

m

b a0( m)

BA

m

b a0

0

( m)h B

AH *)

2

i i

h b,B m a,b,A,B, ,H H

2

k k

a,A m a,b,A,B, ,H Min

a, A, b, B (*) m

(CI) hbp

0h Be

(DI) ap

0 Ae

0h h

b a0B

A

h m

H

m



Absolute masses (ma) and Gibbs excess masses (mGEV, mGEG)

of CO2 adsorbed on wessalite (DAY-zeolite) at T=298K

Absolute and Gibbs excess masses DAY/CO2

14.12

20.87

45.54

29.74

1.410 6.60

86.45

14.66

34.83

1.445.76

89.67

1.444

5.77

0

10

20

30

40

50

60

70

80

90

100

0 1000 2000 3000 4000 5000

mg/g

p [hPa]

100 499 1009 1961 4003

a

GEV

GEG

m ... Dielectric Caloric Meas.(RS, ESch, JUK)

m ... Volumetry, He Vol. (ESch)

m ... Gravimetry, He Vol. (RS)



Measurement Methods

Gas Mixture Sorption



GVC-GET Thermodynamic-Conference Würzburg, 2001

Thermodynamic-conference Würzburg

university of siegen prof. dr. sc. techn. jürgen u. keller ... · pdf filejürgen u....

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