Study on vapor-liquid equilibria of nitrogen + acetone … · Study on vapor-liquid equilibria of...

Prof. Dr.-Ing. Jadran Vrabec ThEt

Thorsten Windmann

Andreas Köster

Jadran Vrabec

Study on vapor-liquid equilibria of

nitrogen + acetone and oxygen + acetone

with a focus on the extended critical region

Potsdam, 10.10.2012

ThEt


Motivation

Associated project in the Collaborative Research Center Transregio 75

"Droplet Dynamics Under Extreme Ambient Conditions" ( )

Investigate droplets that are injected into

trans- or supercritical gases

(rocket combustion systems or future high

pressure fuel combustion systems)

Droplet chamber:

(TU Darmstadt)

acetone in nitrogen

acetone in oxygen

Investigated systems:


4 Lennard-Jones Sites

1 Dipole

1 Quadrupole

Modeling approach CH3-(C=O)-CH3

Acetone: Molecular model

All model parameter for the geometry

and electrostatic are determined by

quantum chemical calculations

Møller-Plesset 2 method


/ mol/l0 2 4 6 8 10 12 14

T / K

200

300

400

500

= 0.4 %

Acetone: Bubble and dew line - adjustment

Experiment (literature) + correlation (DIPPR) Simulation


T / K200 300 400 500

p /

MP

a

0

2

4

p = 4.0 %

T-1 / K-1

0.002 0.003

p /

MP

a

0.01

0.10

1.00

T -1 / K -1

Acetone: Vapour pressure - adjustment



T / K

200 400 600

h

v / k

J/m

ol

0

10

20

30

40

Acetone: Heat of vaporisation - prediction



this work

dr' /

%

-4

4

0

dp / %

-15

15

30

0

T / K

300 400 500

dD

hv / %

-10

10

-0

Acetone: Comparission with models from the literature

AUA4 model, Ferrando (2010)

TraPPE model, Stubbs et al. (2004)


Acetone: Density (homogenious region) - prediction


T / K

150 200 250 300 350

/ 1

0-3

Pas

0.0

0.5

1.0

1.5

2.0along the saturated liquid line

Acetone: Transport properties - prediction

shear viscosity diffusion coefficient


Literature: 49.0 10-10 m2/s

Simulation: 44.2 10-10 m2/s

Deviation: 10 %

(0.1 MPa, 298 K)


T / K

150 200 250 300 350

/ W

/(m

K)

0.00

0.05

0.10

0.15

0.20

0.25

along the saturated liquid line

Acetone: Transport properties - prediction

Thermal conductivity



Unlike interactions A-B:

sB, eB

sAB, eAB

sA, eA

Molecular modeling of mixtures

Prediction ξ = 1

or

parameter ξ fitted to one

experimental data point

p(T, x) or H(T)

Unlike electrostatic interactions in a physically straightforward way

sAB = (sA + sB) / 2

eAB = ξ eA eB

Lennard-Jones parameters of unlike interaction modified Lorentz-

Berthelot combining rule


100 200 300 400 500 600

0

100

200

Kretschmer et al., 1946

Just, 1901

Horiuti et al., 1931

Nitta et al., 1980

Vosmansky et al., 1987

Tsuji et al., 1987

HN

2 / M

Pa

T / K

= 1

N2 + acetone: Adjustment to one Henry‘s law constant

Simulation


100 200 300 400 500 600

0

100

200

Kretschmer et al., 1946

Just, 1901

Horiuti et al., 1931

Nitta et al., 1980

Vosmansky et al., 1987

Tsuji et al., 1987

HN

2 / M

Pa

T / K

= 1

= 0.96

N2 + acetone: Adjustment to one Henry‘s law constant

Simulation ,


xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

50

100

150

200

30°C

70°C

90°C

126.85°C

50°C

0°C-30°C-50°C

LL VL

N2 + acetone: VLE - prediction

Simulation Peng-Robinson EOS (Huron Vidal, UNIQUAC, acentric factor)


xN2

/ mol/mol

0.00 0.02 0.04 0.06

p / M

Pa

0

4

8

12 30°C

70°C

90°C

126.85°C

50°C

0°C

-30°C-50°C

N2 + acetone: Saturated liquid line - prediction

Simulation Peng-Robinson EOS (Huron Vidal, , UNIQUAC, acentric factor)


xN2

/ mol/mol

0.7 0.8 0.9 1.0

p / M

Pa

0.0

0.5

1.0

1.5

2.0

2.5

50°C70°C 30°C

N2 + acetone: Saturated vapor line - prediction

Simulation Peng-Robinson EOS (Huron Vidal, , UNIQUAC, acentric factor)


Apparatus for the saturated liquid line

pressure: max. 20 MPa

temperature: -60 to 130°C

Windmann, T.; Köster, A.: Vrabec, J.,

Journal of Chemical & Engineering Data 57: 1672-1677 (2012).


xN2

/ mol/mol

0.00 0.02 0.04 0.06

p / M

Pa

0

4

8

12 30°C

70°C

90°C

126.85°C

50°C

0°C

-30°C-50°C

Simulation Peng-Robinson EOS (Huron Vidal)

… back to the molecular simulation


xN2

/ mol/mol

0.00 0.02 0.04 0.06

p / M

Pa

0

4

8

12 30°C

70°C

90°C

126.85°C

50°C

0°C

-30°C-50°C

Simulation Peng-Robinson EOS (Huron Vidal) Experiment +

33 experimental data points

N2 + acetone: Saturated liquid line – experimental data



temperature: max. 200°C

Gremer, F.; Herres, G.; Gorenflo, D,

Deutsche Forschungsgemeinschaft Research Report, Wiley-VCH: Weinheim, 2004.

Apparatus for the saturated vapour line


xN2

/ mol/mol

0.7 0.8 0.9 1.0

p / M

Pa

0.0

0.5

1.0

1.5

2.0

2.5

50°C70°C 30°C

Simulation Peng-Robinson EOS (Huron Vidal)

N2 + acetone: Saturated vapor line – experimental data


xN2

/ mol/mol

0.7 0.8 0.9 1.0

p / M

Pa

0.0

0.5

1.0

1.5

2.0

2.5

50°C70°C 30°C


15 experimental data points

N2 + acetone: Saturated vapor line – experimental data


O2 + acetone: Adjustment of the molecular model

Experiment +

xO2

/ mol/mol

0.000 0.002 0.004 0.006

p /

MP

a

0.0

0.2

0.4

0.6

0.8

1.0T = 10°C

Prof. Dr.-Ing. Jadran Vrabec ThEt Peng-Robinson EOS (quadratic, acentric factor)

Experiment +

xO2

/ mol/mol

0.000 0.002 0.004 0.006

p /

MP

a

0.0

0.2

0.4

0.6

0.8

1.0T = 10°C


Prof. Dr.-Ing. Jadran Vrabec ThEt Peng-Robinson EOS Experiment + Simulation

xO2

/ mol/mol

0.000 0.002 0.004 0.006

p /

MP

a

0.0

0.2

0.4

0.6

0.8

1.0T = 10°C

= 0.905


Prof. Dr.-Ing. Jadran Vrabec ThEt Peng-Robinson EOS

O2 + acetone: verification of the molecular model

Experiment + Simulation

xO2

/ mol/mol

0.000 0.002 0.004 0.006

p /

MP

a

0.0

0.2

0.4

0.6

0.8

1.0T = -20°C

= 0.905


xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

20

40

60

80

400K

450K

480K

N2 + acetone: VLE in the extended critical region

Peng-Robinson EOS (Huron Vidal, UNIQUAC, acentric factor)

pc,ace = 4.7 MPa

Tc,ace = 508 K


Qel Tdesired

Qel ~ Tdesired

New apparatus for the VLE measurement Ø

50 c

m

New apparatus



temperature: max. 350°C

New apparatus for the VLE measurement



Peng-Robinson EOS (Huron Vidal, UNIQUAC, acentric factor)

xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

10

20

30

40

50

450 K



Simulation Peng-Robinson EOS (Huron Vidal, UNIQUAC, acentric factor)

xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

10

20

30

40

50

450 K




xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

10

20

30

40

50

450 K



Simulation Peng-Robinson EOS (Huron Vidal, Wilson, acentric factor) Experiment +

xN2

/ mol/mol

0.0 0.2 0.4 0.6 0.8 1.0

p / M

Pa

0

10

20

30

40

50

450 K

PROF. DR.-ING. HABIL. JADRAN VRABEC THERMODYNAMIK UND ENERGIETECHNIK

INSTITUT FÜR VERFAHRENSTECHNIK

ThEt

• Validation with Heat of Vaporization

Density (liquid)

Enthalpy (liquid)

Isobaric heat capacity (liquid)

speed of sound (liquid)

2. virial coefficient

Diffusion coefficient (liquid)

Shear viscosity (liquid)

thermal conductivity (liquid)

Seite 34

• Parameterization with Quantum mechanical calculations

Saturated liquid line

vapor pressure

1. Molecular model for pure acetonn

• Development of a new model

Conclusion

• Compared with two models from

the literature

PROF. DR.-ING. HABIL. JADRAN VRABEC THERMODYNAMIK UND ENERGIETECHNIK

INSTITUT FÜR VERFAHRENSTECHNIK

ThEt

Seite 35

2. System nitrogen + acetone

• Molecular model adjusted to one Henry’s law constant

• Molecular simulation of the VLE (low temperatures and extended critical region)

• Validation with experiment

3. System oxygen + acetone

• Measurement of the saturated liquid line

• Molecular model adjusted to these experimental data points

• Molecular simulation of the VLE

Conclusion

Study on vapor-liquid equilibria of nitrogen + acetone … · Study on vapor-liquid equilibria of...

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