Elsevier

Fluid Phase Equilibria

Volume 408, 25 January 2016, Pages 47-51
Fluid Phase Equilibria

Isobaric vapor–liquid equilibrium for the three binary systems of C14–C16 n-alkane + methyl myristate at 5.00 kPa

https://doi.org/10.1016/j.fluid.2015.08.015Get rights and content

Highlights

  • Isobaric VLE data of three binary systems containing methyl myristate were measured.

  • The new data are useful for the exploitation of diesel/biodiesel blended fuel.

  • The reliability of the experimental data were confirmed by the van Ness method.

  • The VLE data were correlated well by the activity coefficient models.

Abstract

In this work, new isobaric vapor–liquid equilibrium (VLE) data for the three binary mixtures (n-tetradecane + methyl myristate), (n-pentadecane + methyl myristate) and (n-hexadecane + methyl myristate) have been determined at 5.00 kPa by a Rose still. The three binary systems exhibit positive deviations and do not have an azeotropic point. All the experimental data were confirmed to be thermodynamic consistent using the van Ness method. The NRTL, UNIQUAC, and Wilson activity coefficient models were applied to regress the experimental VLE data and the new binary interaction parameters for the three models were obtained. The correlated values of the three models were compared with the measured data, the average absolute deviations of the temperatures and the vapor compositions for all the systems were less than 0.23 K and 0.0024, respectively. Therefore, the three activity coefficient models are suitable for all the three binary systems.

Introduction

Since the traditional fossil energy resources dry up day by day and the environmental concerns are worsening, it is very eager to take immediate action for a sustainable future [1], [2]. Biodiesel, produced from transesterification of vegetable oils or animal fats, is fatty acid ester mixtures and presents the promising alternative substitute to fossil energy due to its renewable and low-emission characters [3], [4]. However, the long-term engine tests using biodiesel as fuels showed ignition delay and higher carbon built up, which suggested that biodiesel is not suitable well to use directly in the existing diesel engines. Fortunately, biodiesel is miscible with fossil-based diesel in any proportion and the blended fuel of biodiesel with diesel exhibits the excellent combustion performance and prevents the engine failure [5].

During the exploitation, transport, and storage of diesel/biodiesel blended fuel, the vapor–liquid equilibrium data of mixtures involving in fatty acid methyl ester (biodiesel) and alkane (diesel) are very essential to accurately understand the boiling point and volatility of the blended fuel [6]. Some VLE data for the mixtures containing fatty acid methyl ester and alkane have been reported in the published paper. Luo et al. [7] determined the VLE data for four binary systems of C11–C14 n-alkane + methyl dodecanoate at sub-atmospheric pressure. Schwarz el at. [8] reported the phase equilibrium data for the binary mixtures (propane + methyl decanoate) and (propane + methyl docosanoate) at high pressure. A survey of literatures showed that there was no published work on the VLE data for the binary mixtures of (alkane + methyl myristate).

In this work, the vapor–liquid equilibrium data for the three binary systems of C14–C16 n-alkane + methyl myristate were determined at 5.00 kPa by a Rose still. The measured VLE data were verified with the van Ness method to check thermodynamic consistency. Furthermore, the non-random two-liquid (NRTL), universal quasi-chemical activity coefficient (UNIQUAC), and Wilson model were applied to regress the measured data and the corresponding parameters were obtained.

Section snippets

Materials

All the reagents used in this study were obtained from J&K Scientific, China. Table 1 presented the information of the four chemicals, including the suppliers, the purity and CAS#. All chemicals were used without further purification. The purities of all the components have been confirmed by GC-FID.

Apparatus and procedure

A modified Rose still was used to determine the experimental VLE data and the detailed procedures were described in our reported literatures [9], [10]. In order to obtain the phase equilibrium

Experimental results

The experimental VLE data and the phase diagram (Txy) for all the binary systems are shown in Table 2 and Fig. 1, respectively. The experimental results indicated that azeotropic behavior did not appear in the three binary mixtures.

The activity coefficients γi were calculated by the following Relation (1):γi=PyiΦˆiv/{pisxiΦisexp[Vil(Ppis)RT]}where Φˆiv presents the fugacity coefficient of component i in the vapor phase, Φis presents the pure component fugacity coefficient at the saturated

Conclusion

The phase equilibrium data containing the mono-alkyl esters of fatty acid (biodiesel) and alkane (diesel) are very essential physicochemical properties for the exploitation, transport, and storage of biodiesel/diesel blended fuel. Then, new isobaric VLE data have been measured for the three binary mixtures (n-tetradecane + methyl myristate), (n-pentadecane + methyl myristate) and (n-hexadecane + methyl myristate) at 5.00 kPa. There was no azeotropic point to be found in the three binary systems. The

Acknowledgements

The authors sincerely acknowledge the Tianjin Natural Science Foundation (13JCYBJC19300) and the National Basic Research (973) special preliminary study program (2014CB260408) for the financial support.

References (15)

  • L. Lin et al.

    Appl. Energ.

    (2011)
  • A. Murugesan et al.

    Renew. Sust. Energ. Rev.

    (2009)
  • D.Y.C. Leung et al.

    Appl. Energ.

    (2010)
  • S.A. Basha et al.

    Renew. Sust. Energ. Rev.

    (2009)
  • C.E. Schwarz et al.

    J. Supercrit. Fluid

    (2015)
  • H. Li et al.

    Fluid Phase Equilib.

    (2014)
  • H. Li et al.

    Chem. Eng. Sci.

    (2015)
There are more references available in the full text version of this article.

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