Experimental Measurements and Modeling Study of LiquidâLiquid

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Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Experimental Measurements and Modeling Study of Liquid−Liquid Equilibrium [(Water + Methyl Oleate + Model Molecules of Tar Issued from the Biomass Gasification Process (Benzene, Toluene, Phenol, Thiophene, and Pyridine)] Georgio Bassil,*,† Joseph Saab,‡ Ilham Mokbel,§,∥ Latifa Negadi,⊥ Jacques Jose,§ and Christelle Goutaudier§ Downloaded via IOWA STATE UNIV on January 16, 2019 at 19:26:57 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

†

Faculty of Engineering, Université Libano-Canadienne, LCU, P.O. Box 32 Zouk Mikael, Aintoura, Kesrouan Lebanon Faculty of Sciences, Department of Chemistry Biochemistry, Group ThEA-Thermodynamic Phase Equilibria and Analysis, Holy Spirit University of Kaslik, B.P. 446, Jounieh, Lebanon § CNRS, Laboratoire des Multimatériaux et Interfaces, University of Lyon, Université Claude Bernard Lyon 1, UMR 5615, F-69622, Lyon, France ∥ University of Lyon, Université Jean Monnet, Saint-Etienne, France 10 rue Tréfilerie, Maison de l’Université CS 82301 42023 Saint-Etienne Cedex 2, France ⊥ LATA2M, Laboratoire de Thermodynamique Appliquée et Modélisation Moléculaire, University of Tlemcen, Post Office Box 119, Tlemcen 13000, Algeria ‡

ABSTRACT: Biomass is known as a potential renewable energy source which can be used in the gasification process in order to produce biomethane gas. One of the major challenges encountered is the elimination of the high level of tar found in the syngas issued from the gasification process. The main purpose of this work is to conduct experimental measurements of liquid−liquid equilibria that will be used for tar removal from the biomass gasification process which is the important step before the distribution and the industrialization of the biomethane gas. In the present work, we propose an experimental and modeling study of liquid− liquid equilibrium of ternary systems of water + solvent (methyl oleate) + model molecules of tar (benzene, toluene, phenol, thiophene, and pyridine) at 303.2 K, 323.2 K, and 343.2 K. The experimental results were correlated using the nonrandom two-liquid (NRTL) and UNIQUAC models and are used to feed the industrial needs for thermodynamic modeling.

1. INTRODUCTION Because of the crisis and the shortage of energy resources of oil and natural gas associated with global warming, the CO2 emissions related to the use of these resources, and the high energy needs growth in emerging markets, the gradual replacement of fossil fuels by renewable resources with the use of biomass is getting increased attention as a potential source of renewable energy1−3 Among all biomass conversion processes (pyrolysis, gasification, and combustion), gasification is the promising technique.1,3,4 But still, one of the major problems of this conversion process to be solved is the reduction of the high level of tar present in the syngas5,6 either in the gasifier itself (known as the primary method) or outside the gasifier (known as the secondary method).1 Tars are molecules that consist of a mixture of hydrocarbons that includes compounds with one or more aromatic cycles which can contain heteroatoms.7 The latter are undesirable to the biomass gasification process and can cause many problems © XXXX American Chemical Society

associated with condensation, the formation of tar aerosols and polymerization to more complex structures, which can deposit in the cooler parts of the process and may cause fouling, catalyst deactivation, and corrosion of the gasifier.1,4,6 The most advanced and reliable technique for the removal of tar from the aqueous medium and from syngas is the use of a suitable extracting solvent. This work focuses on the removal of tars, represented by benzene, toluene, phenol, thiophene, and pyridine, from the aqueous phase downstream of the gasifier that uses biodiesel solvents represented by its major component, methyl oleate. For this purpose, the liquid−liquid equilibria of water + methyl oleate + model molecule of tar (benzene, toluene, phenol, thiophene, and pyridine) have been determined at three different temperatures (303.2 K, 323.2 K, and 343.2 K) Received: July 27, 2018 Accepted: December 30, 2018

A

DOI: 10.1021/acs.jced.8b00659 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

model molecule of tars and the internal standard diluted with methyl oleate and analyzed by GC FID. The water quantification in the organic phase was conducted using the coulometric Karl Fischer (KF) titration. Prior to measurements, the KF determination of water was controlled by analyzing certified water standards “Hydranal-coulomat E” provided by Fluka (relative standard deviation RSD certified 1%), where

and at atmospheric pressure. Experimental data of the liquid− liquid equilibrium have been correlated using the nonrandom two-liquid (NRTL) model and UNIQUAC model.

2. EXPERIMENTAL STUDY 2.1. Materials. Chemical products were used as received from the supplier without any further purification (Table 1). Table 1. Details of the Chemicals Used in This Work Chemical name

Source

Mole fraction purity

CAS

ethanol benzene toluene phenol thiophene pyridine methyl oleate octane

Sigma-Aldrich VWR Prolabo VWR Prolabo Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich Sigma-Aldrich Acros Organics

0.995 0.99 0.99 0.99 0.99+ 0.998 0.99 0.99

64-17-5 71-43-2 108-88-3 108-95-2 110-02-1 110-86-1 112-62-9 111-65-9

RSD(%) = 100

s X̅i

3. RESULTS, ANALYSIS, AND DISCUSSION 3.1. Binary Systems. The mutual solubility data expressed in terms of mole fraction of the binary systems water + or methyl oleate is presented in Table 2 along with the expanded Table 2. Mutual Solubility Data for the Binary System Water + Methyl Oleate Expressed in Mole Fractions (xi ± U(mole fraction)a) at T = 303.2 K, 323.2 K, 343.2 K, and Pressure p = 0.1 MPa

GC FID analyses were conducted throughout the experimental study and no appreciable peaks of impurities which can alter the experimental measurements were detected. A distilled and deionized water by Milli-Q system from Millipore was also utilized for this study. 2.2. Apparatus and Procedure. The experimental apparatus consists of three double jacket thermostatic cells with a thermocouple placed in the cell allowing the measurement of the solution’s temperature. Thus, temperature was measured within ±0.1 K with a thermocouple, whose probe was introduced into the cell by a welded tube.8 These cells were placed in series to control the reproducibility of measurements and check the balance of mass transfer between phases. At the lower part of the cell, the exit valve is equipped with a preheated double drain sampling lines. The first one (in the bottom) aimed to drain the aqueous phase while the second intended for the organic phase. Preheating was required to reduce the risk of adsorption of the analyte in the valves and the draining lines. The water phase is added first to the equilibrium cell by weighing. As for the organic phase, the solvent in which we have previously dissolved our model molecule of tar (benzene, toluene, phenol, thiophene, and pyridine) at different mass concentrations (0.5%, 2%, and 5%) is added to the water phase. These mixtures were vigorously agitated for 8 h with a 1 cm height vortex and then the two phases were settled for 8 h to obtain equilibrium. After equilibrium, samples from the aqueous and organic phases were withdrawn from the cell by means of the preheated sampling lines in order to avoid adsorption phenomena. The samples were collected in an auxiliary solvent (ethanol, the water content of which is about 20 mg dm−3) in order to maintain their homogeneity. The quantification is done by gas chromatography, coupled to a flame ionization detector using the internal standard technique. The analytical conditions of GC FID analysis used are the following: The type of GC is Agilent Technologies 7890A, the column type and specification are Restek Rtx-35 amine (30m; 0.32 mm), the injection type is split (organic phase), splitless (aqueous phase) with an injection volume of 1 μL and a flow rate of the carrier gas He of 2.09 mL/min and the octane as internal standard. Calibration curves were established by analyzing five different standard solutions containing known quantities of the

T/K 303.2 323.2 343.2

x1/10−2 in the organic phase

x2/10−7 in the aqueous phase

Water (1) + Methyl Oleate (2) 2.75 ± 0.12 1.22 ± 0.03 3.82 ± 0.09 3.31 ± 0.09 4.60 ± 0.25 8.34 ± 0.22

Expanded uncertainties “U” with a confidence level of 95% which is the combination of u(T) = 0.1 K, u(m) = 0.1 g (weighing of the mixtures), and u(m) = 0.0001g (analytical weighing of phase samples and the standard solutions) and the u(quantification) due to the repeatability of the analytical measurements (each analytical measurement was repeated at least three times). The number of experimental points = 3. a

uncertainty with a 95% confidence interval. In a previous work, the binary systems for water + p-xylene were described and studied.9 The mutual solubility measurement was repeated at least five to six times with a relative standard deviation (RSD) lower than 4%. Several works and authors studied the mutual solubility measurements relative for the binary system (water/p-xylene) at different temperatures, and the measurements found in our previous work9 are in a good agreement with the literature data. As for the liquid−liquid equilibria for the binary system (water/methyl oleate), we have found the water solubility of methyl oleate at 303.5 K and 323.5 K cited by Oliveira et al.10 using a prediction method (CPA equation state). The solubility of water in methyl oleate at 303.5 K is 2.46.10−2 in mole fraction which is 10% lower than our experimental results and at 323.5 K is 3.9.10−2 in mole fraction which is 2% greater than our experimental value. This means that our experimental measurements are coherent with the literature.10 3.2. Ternary Systems. The experimental study of the liquid−liquid equilibrium measurements for the ternary systems p-xylene-water + benzene + toluene + phenol are studied in a previous work,9 and the data related to the liquid−liquid equilibrium measurements for the ternary systems p-xylene−water + thiophene, + pyridine are reported in another previous work.11 Table 3 reports in mole fractions the liquid−liquid equilibrium results of the ternary systems of methyl oleate−water + benzene + toluene + phenol + thiophene, + pyridine. B



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Table 3. Experimental Liquid−Liquid Equilibrium Data for the Ternary System Expressed in Mole Fractions (xi ± U(mole fraction)b) at T = 303.2 K, 323.2 K, 343.2 K and Pressure p = 0.1 MPa methyl oleate (1) + benzene (2) + water (3) aqueous phase T/K 303.2

323.2

343.2

x1/10 1.20 1.19 1.25 3.38 3.30 3.25 8.39 8.28 8.35

± ± ± ± ± ± ± ± ±

organic phase

−7

0.03 0.08 0.06 0.12 0.10 0.08 0.28 0.27 0.23

x2/10

−5

x1

4.76 ± 0.19 0.813 2.10 ± 0.08 0.903 0.52 ± 0.02 0.954 5.76 ± 0.23 0.801 2.59 ± 0.10 0.892 0.61 ± 0.02 0.944 6.81 ± 0.27 0.795 3.07 ± 0.12 0.884 0.69 ± 0.03 0.936 methyl oleate (1) + toluene (2) + water (3) Aqueous phase

T/K 303.2

323.2

343.2

x1/10 1.28 1.25 1.21 3.37 3.31 3.32 8.38 8.24 8.30

± ± ± ± ± ± ± ± ±

−7

−6

x1

14.5 ± 0.58 0.826 5.21 ± 0.21 0.912 1.31 ± 0.05 0.957 15.5 ± 0.63 0.815 6.00 ± 0.25 0.901 1.62 ± 0.07 0.946 18.3 ± 0.74 0.811 7.48 ± 0.30 0.892 1.93 ± 0.08 0.938 methyl oleate (1) + phenol (2) + water (3) Aqueous phase

T/K 303.2

323.2

343.2

x1/10−7 1.28 1.22 1.25 3.34 3.35 3.38 8.28 8.35 8.38

± ± ± ± ± ± ± ± ±

0.12 0.15 0.10 0.15 0.18 0.21 0.31 0.38 0.44

x1

8.40 ± 0.76 3.30 ± 0.15 0.81 ± 0.04 9.73 ± 0.62 4.04 ± 0.22 0.98 ± 0.04 12.7 ± 0.97 5.21 ± 0.23 1.26 ± 0.05 methyl oleate (1) + thiophene

303.2

323.2

343.2

x1/10−7 1.27 1.28 1.21 3.34 3.22 3.28 8.38 8.37 8.33

± ± ± ± ± ± ± ± ±

0.08 0.07 0.11 0.17 0.28 0.25 0.38 0.35 0.28

0.848 0.916 0.958 0.838 0.909 0.948 0.837 0.903 0.941 (2) + water (3)

303.2

x1

9.48 ± 0.36 0.810 3.74 ± 0.14 0.903 1.18 ± 0.04 0.949 14.5 ± 0.58 0.804 6.00 ± 0.23 0.895 1.79 ± 0.07 0.942 22.4 ± 0.84 0.795 8.33 ± 0.31 0.887 2.63 ± 0.10 0.933 methyl oleate (1) + pyridine (2) + water (3)

323.2

x2/10−3

x1

± ± ± ± ± ±

4.15 ± 0.39 1.72 ± 0.16 0.50 ± 0.02 3.91 ± 0.44 1.59 ± 0.20 0.462 ± 0.03

0.888 0.935 0.963 0.868 0.922 0.952

0.08 0.09 0.11 0.22 0.20 0.26

2.74 2.75 2.75 3.83 3.82 3.83 4.61 4.62 4.59

± ± ± ± ± ± ± ± ±

0.08 0.06 0.07 0.08 0.12 0.15 0.35 0.30 0.18

x2/10−2 14.7 6.06 1.59 14.7 6.13 1.60 14.3 6.18 1.58

± ± ± ± ± ± ± ± ±

x3/10−2

0.59 0.24 0.06 0.59 0.25 0.06 0.62 0.25 0.06

2.75 2.73 2.74 3.82 3.82 3.83 4.60 4.58 4.61

± ± ± ± ± ± ± ± ±

0.04 0.06 0.08 0.9 0.04 0.12 0.22 0.25 0.24

x2/10−2 12.5 5.63 1.43 12.4 5.36 1.34 11.8 5.12 1.29

± ± ± ± ± ± ± ± ±

x3/10−2

0.50 0.23 0.06 0.61 0.24 0.05 0.63 0.23 0.05

2.74 2.75 2.76 3.81 3.80 3.82 4.62 4.61 4.60

± ± ± ± ± ± ± ± ±

0.05 0.06 0.09 0.05 0.09 0.11 0.25 0.22 0.29

x2/10−2 16.3 6.97 2.32 15.8 6.64 2.03 15.9 6.66 2.10

± ± ± ± ± ± ± ± ±

x3/10−2

0.62 0.26 0.09 0.60 0.25 0.08 0.60 0.26 0.08

2.75 2.74 2.75 3.80 3.81 3.82 4.61 4.61 4.61

± ± ± ± ± ± ± ± ±

0.11 0.10 0.15 0.12 0.15 0.18 0.28 0.26 0.32

organic phase

x1/10−7 1.25 1.29 1.21 3.30 3.38 3.36

0.65 0.28 0.07 0.66 0.27 0.07 0.65 0.28 0.07

organic phase x2/10−5

aqueous phase T/K

± ± ± ± ± ± ± ± ±

Organic phase x2/10−4

aqueous phase T/K

16.0 6.97 1.83 16.1 6.95 1.81 15.9 7.02 1.79

x3/10−2

Organic phase x2/10

0.04 0.06 0.08 0.10 0.12 0.14 0.25 0.31 0.33

x2/10−2

C

x2/10−2 8.48 3.72 0.95 9.35 4.01 1.03

± ± ± ± ± ±

0.34 0.15 0.04 0.37 0.16 0.04

x3/10−2 2.74 2.75 2.74 3.83 3.82 3.83

± ± ± ± ± ±

0.12 0.09 0.18 0.17 0.16 0.18



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Table 3. continued methyl oleate (1) + pyridine (2) + water (3) aqueous phase

organic phase

T/K

x1/10−7

x2/10−3

x1

x2/10−2

x3/10−2

343.2

8.38 ± 0.36 8.37 ± 0.28 8.34 ± 0.30

3.26 ± 0.28 1.35 ± 0.11 0.39 ± 0.02

0.858 0.911 0.944

9.65 ± 0.38 4.32 ± 0.17 1.05 ± 0.04

4.61 ± 0.22 4.61 ± 0.29 4.59 ± 0.31

b Expanded uncertainties “U” with a confidence level of 95% which is the combination of u(T) = 0.1 K, u(m) = 0.1 g (weighing of the mixtures) and u(m) = 0.0001g (analytical weighing of phase samples and the standard solutions) and the u(quantification) due to the repeatability of the analytical measurements (each analytical measurement was repeated at least three times). The number of experimental points = 3.

Figure 1. Hand’s correlation for the mixture benzene + water + methyl oleate.

Figure 3. Hand’s correlation for the mixture phenol + water + methyl oleate.

Figure 4. Hand’s correlation for the mixture thiophene + water + methyl oleate.

Figure 2. Hand’s correlation for the mixture toluene + water + methyl oleate.

The coherence of the data for all systems is assured by the linearity of the Hand’s equation plots, which is the case for all of these systems as shown in Figures 1 to5. In Table 4 are reported the fitting parameters and the regression coefficient R2 of the Hand equation. The partition ratio is used to evaluate the solubility of the model molecules of tars in each phase and is given by the following eq 2: xorg K= xaq (2)

Expanded uncertainty was calculated with a 95% confidence interval (Table 3). Since there is no literature data and in order to check the coherence of our experimental values. We have correlated these data by the Hand’s equation:12 ln

φorg Xsolute φorg Xorganicsolvent

= B + A ln

φaq Xsolute φaq X water

(1)

org Xφsolute is the org Xφorganic solvent

where mole fraction of the solute in the organic phase, is the mole fraction of the organic solvent aq in the organic phase, Xφsolute is the mole fraction of the solute in aq the aqueous phase and Xφwater is the mole fraction of water in the aqueous phase.

where xorg = mole fraction of the solute in the organic phase, and xaq = mole fraction of the solute in the aqueous phase D



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Figure 7. Partition ratio and selectivity for the ternary system methyl oleate (1) + toluene (2) + water (3) as a function of the experimental composition of toluene and as a function of temperature.

Figure 5. Hand’s correlation for the mixture pyridine + water + methyl oleate.

Table 4. Hand’s Constants and Regression Coefficients T/K 303.15 323.15 343.15 303.15 323.15 343.15 303.15 323.15 343.15 303.15 323.15 343.15 303.15 323.15 343.15

A

B

Methyl Oleate + Benzene + Water 0.9517 −8.3833 0.964 −8.1662 0.9799 −7.9788 Methyl Oleate + Toluene + Water 1.0126 −9.4035 0.9536 −9.4426 0.9586 −9.2446 Methyl Oleate + Phenol + Water 1.0188 −5.1472 0.9971 −4.9761 0.9935 −4.7514 Methyl Oleate + Thiophene + Water 0.9883 −7.6735 0.9451 −7.2891 0.979 −6.8392 Methyl Oleate + Pyridine + Water 0.923 −3.3451 0.9272 −3.4934 0.9146 −3.7537

R2 0.9986 0.9971 0.9974 0.9999 0.9999 1 0.9996 1 1 0.9999 0.9993 0.9998

Figure 8. Partition ratio and selectivity for the ternary system methyl oleate (1) + phenol (2) + water (3) as a function of the experimental composition of phenol and as a function of temperature.

0.9988 0.9989 0.9986

Figure 9. Partition ratio and selectivity for the ternary system methyl oleate (1) + thiophene (2) + water (3) as a function of the experimental composition of thiophene and as a function of temperature

Figure 6. Partition ratio and selectivity for the ternary system methyl oleate (1) + benzene (2) + water (3) as a function of the experimental composition of benzene and as a function of temperature.

ternary system as a function of the composition of the model molecule of tar and as a function of the temperature. Pyridine and phenol are the two compounds which present the least partition ratio because of their polarity. As for toluene, it is the compound that represents the highest partition ratio.

We have reported the selectivity and the partition ratio for the ternary systems in Figures 6, 7, 8, 9, and 10 for every E



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The effectiveness of a solvent, which is expressed by the selectivity “S” of the solvent,11 is evaluated in this work. The selectivity of the methyl oleate, which measures the ability of a solvent to separate the solutes (benzene, toluene, phenol, thiophene, and pyridine) from water is given by eq 3: S=

ri

qi

3.188 3.923 3.552 2.857 2.999 13.363 0.920

2.400 2.968 2.680 2.140 2.113 11.003 1.400

(3)

4. DATA CORRELATION To fit the experimental data of the ternary systems, the NRTL13 and the UNIQUAC14,15 models were utilized. The nonrandomness parameter (αij) for the NRTL equation is set to 0.2 for the majority of the ternary systems. By minimizing the objective function, OF, we obtain the other parameters for both equations. The OF is given by eq 4:

Table 5. Volume and Surface Area Parameters of the Used Compounds Chemical name

(x 2/x3)water

where the subscript 2 represents the solute and 3 represents water. As seen in the Figures 6 to 10, “S” is remains relatively constant when going throughout the tie lines from high to low concentration of solute. We can conclude that the higher is the temperature, the lower is the selectivity; although the order of magnitude of “S” is respected. This also reflects the same conclusion; the lowest temperature is recommended for the extraction process of these model molecules of tars.

Figure 10. Partition ratio and selectivity for the ternary system methyl oleate (1) + pyridine (2) + water (3) as a function of the experimental composition of pyridine and as a function of temperature.

benzene [16] toluene [16, 17, 18] phenol [17] thiophene [16, 18] pyridine [18] methyl oleate [19] water [16, 17]

(x 2/x3)extractingsolvent

N

OF =

2

3

∑ ∑ ∑ (xijkexptl − xijkcalcd)2 k

j

(4)

i

The root-mean-square deviation (rmsd) describes the quality of a correlation which is calculated using eq 5:

The partition ratio values of the ternary systems decrease as the temperature increases (except the extracting solvent−water + pyridine systems because of the presence of lone pair electrons or a nonbonding pair of electrons on the nitrogen atom increasing the polarity of the aromatic monocyclic molecule). Hence, the lowest temperature is recommended to extract tar from aqueous medium due to its highest partition ratio.

N

rmsd =

2

3

∑∑∑ k

j

exptl calcd 2 (xijk − xijk )

i

6N

(5) exptl

where N is defined as the number of tie lines; x is the experimental mole fraction; xcalcd is the calculated mole

Table 6. UNIQUAC and NRTL Parameters for the Ternary Systems UNIQUAC component i−j

Aij (J mol−1)

1−2 1−3 2−3

−430.80 4385.62 7513.84

1−2 1−3 2−3

−1634.40 4385.62 7659.02

1−2 1−3 2−3

−5627.29 4385.62 4464.78

1−2 1−3 2−3

148.97 4386.92 11752.86

1−2 1−3 2−3

483.67 4386.92 −5547.98

Aji (J mol−1)

NRTL Aij (J mol−1)

rmsd

Methyl Oleate (1) + Benzene (2) + Water (3) 622.54 0.0065 12739.15 2096.55 14410.28 3012.02 10915.22 Methyl Oleate (1) + Toluene (2) + Water (3) 2226.88 0.0073 12022.76 2096.55 7605.57 3128.03 100919.34 Methyl Oleate (1) + Phenol (2) + Water (3) 1962.01 0.023 3686.96 2096.55 6125.70 −12392.83 −800.06 Methyl Oleate (1) + Thiophene (2) + Water (3) 622.10 10549.82 2095.43 0.021 20713.47 3054.32 1132.38 Methyl Oleate (1) + Pyridine (2) + Water (3) −976.45 10549.82 2095.43 0.013 20713.47 3972.71 1132.38 F

Aji (J mol−1)

α

rmsd

−7404.66 49736.85 15243.40

0.20 0.20 0.20

0.019

−6606.75 42785.88 19823.69

0.20 0.20 0.20

0.0062

−5203.17 42756.73 9372.84

0.20 0.20 0.49

0.080

−14244.99 58607.81 9075.58

0.30 0.30 0.30

0.020

−14244.99 58607.81 9075.58

0.30 0.30 0.30

0.060



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Figure 11. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the benzene in the organic and aqueous phase for the ternary system methyl oleate (1) + benzene (2) + water (3) as a function of the composition of benzene at 303.2 K.

Figure 14. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the toluene in the organic and aqueous phase for the ternary system Methyl Oleate (1) + Toluene (2) + water (3) as a function of the composition of toluene at 303.2 K.


Figure 15. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the toluene in the organic and aqueous phase for the ternary system methyl oleate (1) + toluene (2) + water (3) as a function of the composition of toluene at 323.2 K.


Figure 16. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the toluene in the organic and aqueous phase for the ternary system methyl oleate (1) + toluene (2) + water (3) as a function of the composition of toluene at 343.2 K.

fraction; the subscript i indexes the components, j is the phases and k is the tie lines. The volume and surface area parameters (ri and qi) for water, toluene, phenol, benzene thiophene, pyridine and methyl oleate for the UNIQUAC model are presented in Table 5. In Table 6 lists the regressed parameters

of the two equations with the root mean-square deviation (rmsd) values. In Figures 11 to Figure 25, we have presented the experimental molar fraction measurements and the calculated data using the NRTL and the UNIQUAC model of the model molecule of tars in the organic and aqueous phase G



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Figure 17. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the phenol in the organic and aqueous phase for the ternary system methyl oleate (1) + phenol (2) + water (3) as a function of the composition of phenol at 303.2 K.

Figure 20. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the thiophene in the organic and aqueous phase for the ternary system methyl oleate (1) + thiophene (2) + water (3) as a function of the composition of thiophene at 303.2 K


Figure 21. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the thiophene in the organic and aqueous phase for the ternary system methyl oleate (1) + thiophene (2) + water (3) as a function of the composition of thiophene at 323.2 K.


Figure 22. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the thiophene in the organic and aqueous phase for the ternary system methyl oleate (1) + thiophene (2) + water (3) as a function of the composition of thiophene at 343.2 K.

for the ternary systems as a function of the composition and the temperature. As seen in the Figures 11 to 25, the experimental measurements for the model molecule of tars for the ternary systems in both phases agree well with the NRTL and UNIQUAC model.

5. CONCLUSION The liquid−liquid equilibrium study for ternary systems constituted by methyl oleate + water + benzene (or + toluene or + phenol or + thiophene or + pyridine) were conducted at H



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it also decreases when the temperature increases. Hence, the lowest temperature 303.2 K is recommended to extract tar from an aqueous medium and therefore from the biomass gasification process. On the other hand, the descriptions of the systems using NRTL and UNIQUAC models have shown good agreement with the experimental measurements for the model molecule of tars for the ternary systems in both phases. The experimental measurements and the correlation data would be used for industrial purposes in order to feed and/or to consolidate the database of these industries.

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AUTHOR INFORMATION

Corresponding Author

*Email: [email protected].

Figure 23. Experimental and calculated (NRTL, UNIQUAC) molar fraction of the pyridine in the organic and aqueous phase for the ternary system methyl oleate (1) + pyridine (2) + water (3) as a function of the composition of pyridine at 303.2 K.

ORCID

Georgio Bassil: 0000-0001-9170-7631 Funding

This project, VeGaz, was funded by a grant from the Agence Nationale pour la Recherche within the scope of the Bioenergy Program titled: “Green natural gas production from syngas through biomass gasification”. Acknowledgements are also expressed to MIRA program (Mobilité Internationale RegionsAlpes). Notes

The authors declare no competing financial interest.

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REFERENCES

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Article

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