Third International Symposium on Environmental and Water Resources
Engineering
2-3 June 2015, Tehran , Iran
Simulation of Ethylene glycol Extraction with 1-Heptanol as Solvent to prevent
infiltration to groundwater
H. Ghazvini Nazmabad*, H. Ghanadzadeh, A. Ghanadzadeh
Department of Chemical engeeniring, University of Guilan, Rasht, Iran
Hadiseh.ghazvini@yahoo.com
1. INTRODUCTION
ethylene glycol (EG) is an organic compound primarily used as a raw material in the
manufacture of polyester, fibers and fabric industry, and polyethylene terephthalate resins
(PET) used in bottling. A small percent is also used in industrial applications like antifreeze
formulations and other industrial products [1,2]. Ethylene glycol is a high production volume
chemical, it breaks down in air in about ten days, and in water or soil in a few weeks. It enters
the environment through the dispersal of ethylene glycol containing products, especially at
airports where it is used in deicing agents for runways and airplanes. ethylene glycol is a
teratogen. Based on rather extensive database, it induces in rats and mice by all routes of
exposure [3,4]. In this study, extraction of ethylene glycol from aqueous solution was studied
usig 1-Heptanol as a solvents at T = 25 ºC, and atmospheric pressure.
2. SIMULATION
2.1 Problem definition
The feed is a mixture made up of 80 mole% of water and 2 mole% of EG, with a flow rate of
80 kg/hr. The flow diagram for EG extraction process is shown in Fig 1. The extraction
column was optimized at 6 plates and data for distillation column is shown in Table 1.
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Third International Symposium on Environmental and Water Resources
Engineering
2-3 June 2015, Tehran , Iran
Figure 1. Flow diagram of Ethylene glycol separation process
Table 1. Initial input data for distillation column
Number of stages
Feed stage
Reflux ratio
Distillat ratio
13
5
1.5
0.9
2.2 Property packeg
Computer simulation using commercial process simulators is a useful tool to predict
qualitatively the influence of the operating variables on the column performance, provided
that the interaction binary parameters for the studied mixture are available in their own
databank. The accuracy of the simulated results is strongly dependent on the quality of the
binary parameters from the liquid phase activity coefficient models for this simulation,
UNIQUAC activity model was chosen because it was the best model to study the phase
behaviour of Liquid-Liquid Equilibrium (LLE), Vapour–Liquid Equilibrium (VLE) [5].It
should be noted that, in this table temperature unit is oC. Mass fraction of components in
streams are presented in Table 2.
Table 2. Mole fraction of components in streams
Stream ID
Water
Ethylene glycol
Recycle
Water
0.915
Trace
0.941
C2 H6O2
0.069
1.000
0.051
C8 H18O3
0.016
130 ppm
0.007
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Third International Symposium on Environmental and Water Resources
Engineering
2-3 June 2015, Tehran , Iran
2.3 Extractive distillation
Extractive distillation has the inherent disadvantage of introducing a third component into the
system (the solvent) that will appear in the product streams, which necessarily have to be
recovered. So, the extractive system must show significant economic advantages over the
pressure-swing system to make it the process of choice.
3. SELECTIVITY FACTOR
Separation factor is defined as the ratio of distribution coefficients of phosphoric acid (D2) to
water (D1) (Eq. (1)):
S
D2 w23 w21

D1 w13 w11
(1)
w11, and w21 are the mass fractions of water and EG in the aqueous phase, respectively and
listed in Table 3. w13, and w23 are the mass fractions of water and PA in the organic phase,
respectively and listed in Table 3. The separation factors for the organic solvent are greater
than one (S>>1) for the system, which means that the simulation of WEG extraction using 1Heptanol is possible. That the distribution coefficients and the separation factors for the
system at T=25oC are listed in Table 3.
Table 3. Mass fractions of organic phase in column extraction and distribution coefficients of water (D1)
and EG (D2) and separation factors (S).
w13
w23
D1
D2
S
0.0001
0.9999
0.0001
5.2351
52351.0000
4. CONCLUSIONS
The separation of substances by distillation or other methods that have high energy
consumption and are harmful to the environment, are not environmentally and economically
useful. Solvent extraction method has been proposed to be a promising method with its high
distribution coefficient, simplicity, and low energy demand. The simulation of processes with
a commercial software program (Aspen plus) used appropriately is a very powerful tool to
analyze the separation EG of the aqueous mixtures with 1-Heptanol. The thermodynamic
equations used here are UNIQUAC equations. The selectivity factors for this solvent were
calculated and the high value of this factor (s>>1), is reason for be suitable of the solvent for
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Third International Symposium on Environmental and Water Resources
Engineering
2-3 June 2015, Tehran , Iran
extraction of EG in aqueous solution.
5.
REFERENCES
[1] H. C.Fuller, Ethylene Glycols, Products & Technology American chemistry council , Ethylene Glycol _
Its properties and uses, Indtitute of industrial research,Washington.D.C.
[2] Y. Kakimoto, Y. Oka, Method for production of ethylene glycol, US 6417411 B2, (2001).
[3] Statement of the Science Report for Ethylene Glycol, (2013-2014).
[4] J. M. Hollis, F. J. Lovas, P. R. Jewell, L. H. Coudert, Interstellar Antifreeze: Ethylene Glycol, The
Astrophysical, (2002).
[5] Garcia-Flores BE, Galicia-Aguilar G, Rincon RE, Trejo A. Fluid Phase Equilib. 185 (2001) 275-293.
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