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Available online at www.sciencedirect.com

Fluid Phase Equilibria 264 (2008) 259263

Measurement and correlation of vaporliquid equilibriafor the system carbon dioxidediisopropyl ether

Caifeng Zhu, Xianghong Wu, Danxing Zheng , Wei He, Shuhong Jing

College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China

Received 30 May 2007; received in revised form 14 November 2007; accepted 15 November 2007

Available online 22 November 2007

Abstract

A view cell with on-line sampling of the vapor and the liquid phase has been built for measuring vaporliquid equilibria data under highpressure. The samples are analyzed by gas chromatography. VLE data for the system carbon dioxidediisopropyl ether has been measured at

265.15333.15 K and 0.52.5 MPa. The isothermal data were correlated using the PengRobinson equation. The correlated results agree well with

the experimental results. The experiments confirm that diisopropyl ether is an excellent absorbent of carbon dioxide.

2007 Elsevier B.V. All rights reserved.

Keywords: Vaporliquid equilibria; Carbon dioxide absorbent; Diisopropyl ether; Thermodynamic correlation

1. Introduction

The emission of carbon dioxide (CO2) has been identified as

the main contributor to global warming and climate change. The

challenge for modern industry is to find cost-effective solutionsthat will reduce the release of CO2 into the atmosphere. Reduc-

tion of CO2 emissions can be achieved by a variety of means

[1]. A physical absorption process is one of the most important

possibilities. The advantage of this method is that it requires

relatively little energy. Diisopropyl ether, an excellent solvent,

is expected to absorb CO2 [2,3]. So the vaporliquid equi-

librium (VLE) data of the system carbon dioxidediisopropyl

ether is very important for understanding this absorption

process.

Earlier studies on the solubility and the VLE of the car-

bon dioxidediisopropyl ether system are only made Zhang et

al. [2] at experimental temperatures of 299.15 K, 308.65 K and

318.15 K, and pressure ranging from 0.82 MPa to 8.32 MPa. Thedetermination of the solubility of carbon dioxide in diisopropyl

ether is the first step in the design of a diisopropyl ether-based

carbon dioxide absorption process and was considered as the

main objective of this paper. The VLE behavior of the carbon

dioxidediisopropyl ether binary system was studied by a set

Corresponding author.

E-mail address: dxzh@mail.buct.edu.cn(D. Zheng).

of VLE device [4,5] which was established on a serial VLE

experimental methods [611] for references.

2. Experimental

2.1. Chemicals

Carbon dioxide with purity greater than 99.9 mass% was pur-

chased from Zhaoge Gas Co. Diisopropyl ether was purchased

from Tianjin Jinke Fine Chemical Co.; the purity was greater

than 99 mass%. These chemicals were used without further

purification.

2.2. Apparatus

The phase equilibrium apparatus used in this study is shown

in Fig. 1. It is a static type apparatus and its design was similar

to that used by Baba et al. [12]. There are three main sections:

one for the high-pressure equilibrium cell, another for the input

of the sample and the last one for on-line gas chromatography

(GC) analysis of the composition of the equilibrium phases.

The stainless steel equilibrium cell has an internal volume of

120 mL. The maximum operation pressure is 6 MPa. In the side

of the equilibrium cell is a glass window for visual observation

of the phase behavior.

The equilibrium cell is shown in Fig. 2. It was fixed inside a

thermostat bath filled with water. An electric heater, connected

0378-3812/$ see front matter 2007 Elsevier B.V. All rights reserved.

doi:10.1016/j.fluid.2007.11.010

mailto:dxzh@mail.buct.edu.cnhttp://localhost/var/www/apps/conversion/tmp/scratch_2/dx.doi.org/10.1016/j.fluid.2007.11.010http://localhost/var/www/apps/conversion/tmp/scratch_2/dx.doi.org/10.1016/j.fluid.2007.11.010mailto:dxzh@mail.buct.edu.cn

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260 C. Zhu et al. / Fluid Phase Equilibria 264 (2008) 259263

Fig. 1. Schematic diagram of the experiment apparatus: (1) gas cylinder; (2) gas storage tank; (3) liquid injector; (4) stirrer; (5) constant temperature water bath; (6)

equilibrium cell; (7) magnetic mixer; (8) cooling unit; (9) temperature controller; (10) cushion tank; (11) gas chromatography; (12) vacuum pump; (13) computer.

to a PID thermal regulator (Model WD-D90) that was supplied

by Wideplus Precision Instruments Co., was immersed in

water. The temperature stability of the bath was

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262 C. Zhu et al. / Fluid Phase Equilibria 264 (2008) 259263

Fig. 4. VLE for the system carbon dioxide + diisopropyl ether: mole function

CO2 in the vapor phase at five temperatures: () 265.15 K; () 273.15 K; ()

293.15 K; () 313.15 K; () 333.15 K. -: PR correlation.

study agrees well with the calculated data and the reliability ofthe apparatus is confirmed.

The results in Fig. 3 demonstrate that the liquid mole fraction

of carbon dioxide in diisopropyl ether increases with increasing

pressure but decreases with increasingtemperature. In the exper-

imental temperature range, the liquid mole fraction of carbon

dioxide changes strongly, especially at low temperatures. For

example, the liquid mole fraction of carbon dioxide is 0.7589 at

a temperature of 265.15 K and pressure of 2.478 MPa. This con-

firms that diisopropyl ether is an excellent absorbent for carbon

dioxide.

In the PR equation, the interaction parameter kij can be

obtained from experimental data. This parameter could be used

to predict theequilibriumdata of thecarbon dioxidediisopropylether system. The calculated results from the experimental data

show in Table 3.

The deviations of the calculated results by PR equation from

the experimental data were shown in Fig. 5. It can be seen that

Fig. 5. VLE for the system carbon dioxide + diisopropyl ether: vapor phase

composition deviations of the experimental data from the calculated results at

five temperatures: () 265.15K; () 273.15K; () 293.15K; () 313.15 K;

() 333.15 K.

Table 3

Parameters of the PR equation for the carbon dioxidediisopropyl ether system

T(K) kij

265.15 0.06197

273.15 0.04081

293.15 0.08942

313.15 0.03274

333.15 0.02353

the calculation data agree well with the experimental results. So

the PR equation is able describe the VLE data of the system

carbon dioxide + diisopropyl.

4. Conclusion

The VLE data are presented for the system carbon diox-

ide + diisopropyl ether at temperatures of 265.15 K, 273.15 K,

293.15 K, 313.15 K and 333.15 K and pressures of 0.5 MPa,1.0 MPa, 1.5 MPa, 2.0 MPa and 2.5 MPa.

The VLE data were correlated with the PR equation of state.

The measured data in the study agrees well with the calcu-

lated data and the reliability of the apparatus in the study was

confirmed.

It was proven that diisopropyl ether is an excellent absorbent

of carbon dioxide. Therefore, diisopropyl ether, which has con-

siderable potential as a new carbon dioxide absorbent, is worthy

of further research.

List of symbols

a energy parameter of the PR equation (Pa m6 kmol2)b co-volume parameter of the PR equation (m3 kmol1)

k binary interaction parameter of the PR equation

p pressure (MPa)

R gas constant (8314.5 m3 Pa kmol1 K1)

T temperature (K)

V molar volume (m3 kmol1)

x liquid phase molar fraction

y vapor phase molar fraction

Greece letters

parameter of the PR equation

difference operator acentric factor

Subscripts

c critical property

i, j component i or j

m molar property

r reduced property

Superscripts

cal calculated property

exp experimental property

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C. Zhu et al. / Fluid Phase Equilibria 264 (2008) 259263 263

Acknowledgements

The support provided by the National Key Project (Nos.:

90210032, 50576001) for the completion of the present work

is gratefully acknowledged.

References

[1] E.J. Granite, T. Brien, Fuel Process. Technol. 68 (2005) 1423

1434.

[2] N.W. Zhang, W. Wang, X.Y. Zheng, Nat. Gas Chem. Technol. 6 (1997)

5256.

[3] D.X. Zheng, H.G. Jin, W. Cao, L. Gao, A separation process of dimethyl

ether, Appl. CN02160111.9.

[4] W. He,D.X. Zheng, X.H. Wu, et al., Petrochem. Technol. 4 (2007)365368

(in Chinese).

[5] W. He, Experiment and Correlation of VaporLiquid Equilibrium for

Ethylene and Toluene Binary System, Beijing University of Chemical

Techonology, Master Thesis, 2007 (in Chinese).

[6] K. Hyo, N. Kunio, H. Mitsuho, J. Chem. Eng. Jpn. 14 (1981) 16.

[7] E. Maria, B. Willlam, J. Chem. Eng. Data 29 (1984) 324329.

[8] M. Mohamed, J. Richard, J. Chem. Eng. Data 45 (2000) 10801087.

[9] Y. Charles, B. Willlam, J. Chem. Eng. Data 26 (1981) 155159.

[10] J. Yoon, H.S. Lee, J. Chem. Eng. Data 38 (1993) 5355.

[11] J.H. Hong, R. Kobayashi, Fluid Phase Equil. 41 (1988) 269276.[12] A. Baba, P. Guilbot, D. Richon, Fluid Phase Equil. 166 (1999) 225236.

[13] L.S. Lee, H.J. Ou, H.L. Hsu, Fluid Phase Equil. 231 (2005) 221230.

[14] S. Matteo, E. Nicola, J. Supercrit. Fluids 33 (2005) 714.

[15] T.X. Li, K.H. Guo, R.Z. Wang, J. Therm. Sci. 2 (2001) 127132.

[16] C.H. Cheng, Y.P. Chen, Fluid Phase Equil. 234 (2005) 7783.

[17] S.M. Stanley, Phase Equil. Chem. Eng., Lond. (1985).

[18] D.R. Lide, CRC Handbook of Chemistry and Physics, 77th Ed., Chemical

Rubber Co., 1997.