Study of Aqueous Ethanol-Diesel-Biodiesel Prepared by Near-Isochoric

Sub Critical Trans-Esterification

HANNY F. SANGIAN1, MEIGA P. PAENDONG1, JOSHUA R. ROMBANG1, JIL A. LAMETIGE1,

GUNTUR PASAU1, MARIA BOBANTO1, RONNY PURWADI2, RAMLI THAHIR2, BAYU

ACHIL SADJAB3, VECKY A. J. MASINAMBOW4, TUN SRIANA5, ZAMI FURQON5, SILVYA

Y. AGNESTY5, ARIEF WIDJAJA6

1Department of Physics,

Sam Ratulangi University, 95115 Manado,

INDONESIA

2Department of Chemical Engineering,

Politeknik Negeri Samarinda, 75136 Samarinda,

INDONESIA

3Department of Physics,

Halmahera University,97762 Tobelo,

INDONESIA

4Department of Economic Development,

Sam Ratulangi University, 95115 Manado,

INDONESIA

5Department of Oil and Gas Processing Engineering,

Polytechnic of Energy and Minerals, 58315, Cepu Blora,

INDONESIA

6Department of Chemical Engineering

Institut Teknologi Sepuluh Nopember, 60111 Surabaya,

INDONESIA

Abstract: - This work aims at preparing the blended fuels in a stable emulsion in which the biodiesel was

obtained from palm oil with applying the near isochoric subcritical trans-esterification. The work procedures

are the following: the preparation chemicals needed; the synthesis of the biodiesel; POME (palm oil methyl

ester) analysis; the blending process of the aqueous ethanol-biodiesel (Aq.Et-BD) and ethanol-diesel-biodiesel

(Aq.Et-BD-D) whereby they formed in a stable emulsion. It was obtained that the compositions of water,

ethanol, and biodiesel using ethanol 94-97% were ranged from 0.69-1.60, 10.74-38.40, and 69.57-88.57%. By

employing ethanol with concentration 94-95%, the emulsion appeared many droplets distributed throughout the

substance. It was observed by increasing biodiesel composition after a stable emulsion attained the phase did

not change. After emulsions blended, the work was proceeded with the measurement of the fuel parameters

such as density, SG, API, RPV, flash and pour points, cetane number, and distillation properties.

Keywords: Biodiesel, Blended Fuels, Emulsion, Ethanol, Stable Emulsion

Received: March 18, 2021. Revised: January 24, 2022. Accepted: February 19, 2022. Published: April 4, 2022.

1 Introduction

The bio-resources materials have been attracting

widely scientists aiming to overcome the deficiency

of fossil-based fuels [1,2]. Some renewable

materials had been successfully synthesized and

utilized for energy purposes [3,4]. Lignocellulosic

materials were also converted into more valuable

chemicals, namely, sugars which would be prepared

fuels [5,6]. The biofuels were successfully

manufactured, such as bioethanol, biogas hydrogen,

methane, and solid fuel [7,8,910].

Furthermore, investigators around the world

have been preparing the biodiesel by utilizing the

full range of the edible- and non-edible- crude oils

from plants such as palms, animals, Calophyllum

inophyllum (nyamplung fruits), Jatropha curcas,

soybean, Pongamia pinnata, tobacco seed (Nicotiana

tabacum L.), rice bran, Madhuca indica, Azadirachta

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indica, Hevea brasiliensis, castor, linseed, and

microalgae as reviewed by the author [11].

The method employed on biodiesel production

was still dominated by a conventional technique

called trans-esterification. It can be carried out at

atmospheric-, or high pressure and temperature

conditions (sub- and supercritical fluids methods).

Generally, the trans-esterification using subcritical

fluids still employs base-based catalysts, namely

KOH and NaOH [12]. Currently, the sub- and

superfluids started to use a chemical reaction to

produce biodiesel using less catalyst or even without

catalyst [13].

Bioethanol is also being developed purposing to

change a part of gasoline for heat engine fuel. The

utilization of ethanol for fuel purposes is facing a

challenge, for it is mainly derived from food,

namely, corn and sugarcane. On the other hand,

generation II ethanol, which is converted from

lignocellulosic materials, is not feasible for scale-up.

The most condition for employing lignocellulose is

the pretreatment and enzymatic processes that are

costly [7]. To overcome the problems must be

increased to exceed human needs. The countries

United States of America and Brazil are successful

in developing ethanol, becoming a lucrative

business thanks to a surplus of the starch and sugar

from corn and sugarcane [14,15].

The works of blended fuels were reported by

authors around the world of which the mixture

consisted of ethanol-gasoline, ethanol-biodiesel,

ethanol-diesel, and ethanol-diesel-biodiesel

[16,17,18,19]. The other authors discovered that

ethanol blends E85 of the gasohol fuel was a

threshold blend whereby the fuel was not

economical to produce since the caloric value

started decreasing highly. Still, all ethanol blends

showed less carbon emission [20]. The ethanol

addition in large fraction into biodiesel-diesel blends

could be applied to the high load diesel engine. The

study found that the ignition delay increased by 38.5

%, but the burning duration decreased by 49 %. The

negative impact of the ethanol blends the NOx

emission inclined significantly because of the

oxygen existence [21]. When the ethanol was added

to biodiesel, the combustion parameters were

changed. The biodiesel-ethanol blends could

improve fuel consumption and thermal efficiency

compared to that of pure biodiesel. The parameters,

heat release at any time, ignition delay, and

smoke emission was higher if using biodiesel-

ethanol blends [22].

As described previously, biodiesel can be

produced by utilizing subcritical fluids with a

pressurized gas such as CO2, N2, and H2. This

investigation was to synthesize biodiesel from palm

oil, applying the near isochoric subcritical. The

application of the adjacent isochoric subcritical

trans-esterification aims to avoid using the

pressurized gas. Furthermore, the work does not use

complicated instruments; neither were installed

valves and regulators. The brief procedures are as

follows: design and construction of the reactor,

biodiesel preparation, characterization of POME

employing GC/MS, the blending process of aqueous

ethanol-biodiesel, and aqueous ethanol-biodiesel-

diesel, and fuel parameters measurements.

2 Methodology

2.1 Materials

The chemicals employed were a commercial palm

oil ordered from the market in Minahasa Regency,

North Sulawesi Indonesia. The aqueous ethanol was

processed from a palm tree (Arenga Pinnata) sugar.

The sap was fermented to be liquor and then

distilled using a tool called reflux column filled with

pores packing materials as used previously [23]. By

using that technique yielded bioethanol with

concentrations of 94-96%. The higher purity, 97%,

was obtained employing an activated particle sieve

(lime).

2.2 Instrumentation

A home-made reactor was designed and constructed

with dimensions volume 600 mL and a tube 2

inches equipped by a thermometer (56-238; Sellery;

Singapore) and fluid-filled pressure gauge (56-374;

Sellery; Singapore). Instrument (GCMS-2010 QP;

Shimadzu; Japan) based at Central Lab, Malang

State University, East Java Indonesia, was used to

identify the methyl esters formed whereby the

operational conditions were 5 bar. The American

Society for Testing and Materials (ASTM)

procedures were followed to measure the fuel

parameters in which the work was conducted at the

Oil and Gas Engineering Laboratory, Polytechnic of

Energy and Mineral Polytechnics, Cepu Blora

Central Java, and at Samarinda State Polytechnic,

East Kalimantan Indonesia. The fuel parameters

measured included ASTM assignments, instrument

specification, manufacturer, and the country as

follows: density (15oC; D4052; Koehler; New York

USA), viscosity (40oC; D445; KV1000; Kohler;

New York USA), ASTM color (D1599; K13200

Petroleum Colorimeter; Koehler; New York USA),

flash point PMCC (D93; Electric Pensky – Martens;

SDM Torino, Italy), Reid vapor pressure (D323;

Koehler; New York USA), pour point (D97; Lawler

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Manufacturing Company; Indianapolis USA), and

distillation (D86; Koehler; New York USA).

2.3 Procedures

The technology used in the present work followed

and modified the previous works as previously

reported [24-25]. The proposed method considered a

new process was a near isochoric subcritical trans-

esterification.

The biodiesel was synthesis by reacting the

palm- or coconut oil, methanol enhanced by catalyst

KOH with a ratio of 10.75: 2.52: 0.01 (w/w), and

the pressure was set at 1-15 bar and the temperature

varied from 30-150oC for 1 h. The mixture was

blended in a 1-liter flask and then was poured into

the reactor. After the lid of the reactor was closed

tightly, the gas stove was turned on. The gas was

weighted in each experiment. All processes were

carried out for 1 h, and during heating, the reactor

was shaken each 5 min.

A B

Fig. 1: The GC/MS spectra of the methyl esters and retention time (RT) by employing the near isochoric

subcritical esterification mixture V 575 mL; P=1-15 bar (A) and V 550 mL; P=1-7 bar (B) for 1h; and T=30-

150 oC

Table 1. The yield of biodiesel obtained assigned by yield1, yield2, yield3, and yield4 with two volumes of

mixture 575 and 550 mL conducted at 15 and 7 bar for 1 h and maximum temperature 150oC.

Name of sample

Yield1 (%w/w)

Yield2 (%w/w)

Yield3 (%v/v)

Yield4 (%v/v)

POME (575ml; 15 bar)

88.96

74.20

92.38

74.78

POME (550 mL; 7 bar)

88.35

73.94

89.84

72.72

After trans-esterification finished, the gas

stove was turned off, and the reactor was cooled by

using a wet cloth until the temperature was 30 oC. In

this process, the pressurized gas was not employed,

aiming at simplifying and declining the production

cost. The mixture was poured into a flask and kept

for hours until biodiesel and glycerol were separated

into two phases.

The biodiesel was removed to another flask

using a small tube where the tube edge touched just

above the glycerol surface, and the flask heights are

different from the ground. After the wash step, the

samples were poured inside a bottle and stored in a

rustic cabinet. The POME obtained was

characterized, employing the GC/MS measurement,

whereby it was to know the type of the methyl ester

compounds. The compound analysis referred to

literature reported by authors [26].

Table 2. The palm oil methyl ester compound (POME) and retention time (RT) by employing the near isochoric

subcritical esterification (mixture V 575 mL; P=1-15 bar; t= 1h; T=30-150 oC ratio (in V) palm oil to methanol

= 465.45:109.11; mass of KOH = 5g

Compound

Formula

Area (%)

6.34

Octanoic acid

C9H18O2

0.04

12.42

Decanoic acid

C11H22O2

0.03

17.85

Dodecanoic acid

C13H26O2

0.37

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The simple steps were conducted at the blending

of biodiesel-aqueous ethanol and biodiesel-aqueous

ethanol-diesel. The procedures are the following:

The 7 mL aqueous ethanol was poured into a flask

100 mL, and then biodiesel was mixed gradually

while being shaken slowly. When the biodiesel was

entirely dissolved with aqueous ethanol, the addition

was stopped.

The blended fuel of aqueous ethanol-biodiesel

(AqEB) in the stable emulsion was obtained with a

composition (in V) VAq.Et.:VBD, or VEt:BD:W

whereby VAq.Et., VBD, VEt., and W were

assigned as the volumes of the aqueous ethanol,

biodiesel, pure ethanol, and water, respectively.

The stable emulsions of aqueous ethanol-

biodiesel-diesel (AqE-BD) were as follows: The

aqueous ethanol was mixed firstly with diesel at a

specific ratio. Biodiesel was poured gradually into

the mixture while shaken gently until the three

components were dissolved fully.

The composition of the aqueous ethanol,

biodiesel, and diesel (AqE-BD-D), or the pure

ethanol, biodiesel, diesel, and water (in V) whose

assignments were VAq.Et.:VBD,:VD, or

VEt.:VBD,:VD:W was established. The volume of

pure ethanol was obtained from percentage times an

amount of aqueous ethanol, and the rest was the

volume of water.

The present work, the literature authored by

[27], and the instrument instructions were a

reference for fuel parameters discussion. Notably,

the density, specific gravity (SG), API, Reid vapor

pressure (RVP) followed the standard procedure of

the American National Standard, as stated on the

guidelines entitled Manual of Petroleum

Measurement Standards/MPMS, Chapter. The

distillation property was modified the investigation

published by authors [28].

3 Results and Discussions

3.1 Facts Discovered

Before the experiment, the reactor designed and

constructed was carried out a test purposing to know

the property and safety. The application of the near

isochoric subcritical method for biodiesel

preparation found useful facts.

If the volume of the mixture was just similar to

the reactor volume 600 mL, the pressure increased

fast after the temperature reached 150 oC. Even

though the temperature increased slowly, the

pressure increased extremely from 15 until 50 bar

just in few seconds. This situation was a danger and

not safe for practical operation in Lab- and

industrial scales. It was discovered that the

reactants, palm oil, and methanol were difficult at

reacting to be a biodiesel product whose the mixture

volume was 0.99 of reactor volume. Sometimes the

products obtained were only two-phase substances,

palm oil, and methanol or one phase solution of

which it was still under investigation.

In spite of a high pressure applied, sometimes the

reactants could not react to the desired product,

which might be caused by less collision between

particles. Based on the previous description, the

volume of the mixture was decreased to 575 and

550 mL to minimize the explosion of the reactor.

When the amount of broth at 575 mL, the pressure

could be attaining 15 bar and increase above it but

slow, meanwhile 550 mL only achieved 7 bar.

22.55

Tetradecanoic acid

C15H30O2

1.24

25.28

Pentadecanoic acid

C16H32O2

0.02

28.15

9-Hexadecenoic acid

C17H32O2

0.14

29.23

Hexadecanoic acid

C17H34O2

37.42

33.21

Heptadecanoic acid

C18H36O2

0.08

35.43

9,12-Octadecadienoic acid

C19H34O2

12.58

35.69

9-Octadecenoic acid

C19H36O2

40.95

36.31

Octadecanoic acid

C19H38O2

6.24

40.42

11-Eicosenoic acid

C21H40O2

0.13

40.96

Eicosanoic acid

C21H42O2

0.49

44.30

Hexadecanoic acid

C19H38O4

0.06

44.64

Heptadecanoic acid

C19H38O2

0.08

47.26

9-Octadecenoic acid

C21H40O4

0.06

47.81

Tetracosanoic acid

C25H50O2

0.03

49.26

2,6,10,14,18-Pentamethyl

C25H42O2

0.03

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Table 3. The palm oil methyl ester compound (POME) and retention time (RT) by employing the near isochoric

subcritical esterification (mixture V 550 mL; P=1-7 bar; t= 1h; T=30-150 oC ratio (in V) palm oil to methanol =

445.45:109.11; mass of KOH = 4.5g

Compound

Formula

Area (%)

6.34

Octanoic acid

C9H18O2

0.04

12.42

Decanoic acid

C11H22O2

0.04

13.51

Phenol, 2-methoxy-3-(2-propenyl)

C10H12O2

0.03

17.86

Dodecanoic acid

C13H26O2

0.35

22.13

9-Octadecenoic acid

C19H36O2

0.68

22.45

9-Octadecenoic acid

C19H36O2

0.63

22.55

Tetradecanoic acid

C15H30O2

2.00

25.29

Tetradecanoic acid

C15H30O2

0.04

28.17

9-Hexadecenoic acid

C17H32O2

0.17

29.20

Hexadecanoic acid

C17H34O2

36.23

33.23

Hexadecanoic acid

C18H36O2

0.07

33.76

9-Octadecenoic acid

C19H36O2

0.32

35.42

9,12-Octadecadienoic acid

C19H34O2

12.12

35.67

9-Octadecenoic acid

C19H36O2

40.88

36.31

Octadecanoic acid

C19H38O2

5.33

40.43

11-Eicosenoic acid

C21H40O2

0.16

40.96

Eicosanoic acid

C21H42O2

0.38

44.06

1,2-Benzenedicarboxylic acid

C24H38O4

0.12

44.85

1,2-Benzenedicarboxylic acid

C24H38O4

0.11

47.27

9-Octadecenoic acid

C21H40O4

0.09

3.2 Yield of Product

The yields obtained were influenced mainly by the

temperature, amount of catalyst, time, and reaction

time. The yields are defined as follows: yield1 and

yield2 are defined as the mass of product/mass of

palm oil and mass product/mass of palm oil +

methanol. In contrast, yield 3 and yield4 are

formulated as the volume of product/volume of

palm oil and volume of product/volumes of palm oil

+ methanol, respectively, as shown in Table 3. Two

volumes of the mixture were employed, namely,

575 mL (15 bar) and 550 mL (7 bar).

The data show that the yield1 and yield2 of

POME, whereby the volume of the mixture was 575

(15 bar), were 88.96 and 74.20 % meanwhile, yield3

and yield4 were 92.38 and 74.78 %. Meanwhile,

when the volume of the mixture was 550 mL and

conducted at 7 bar, the yield1, yield2, yield3, and

yield4 obtained 88.35, 73.94, 89.84, and 72.72 %.

According to data shown that the yields obtained,

which were conducted at 15 bar and 575 mL, were

relatively more significant than those of 7 bar and

550 mL. The pressure could be influencing the yield

of biodiesel obtained, which was comparable with

previous work [29].

3.3 Compound Analysis

According to GC/MS measurement (Fig. 1), the

methyl esters synthesized from palm oil were

diverse that were recorded from C9H18O2

(Octanoic acid) until C25H42O2 (2,6,10,14,18-

Pentamethyl) and the compositions were varied

depending on RT as presented in Table 2. Two

peaks appear on the spectra and represent the

compounds dominated by the POME. The most

significant component of the POME (575ml; 15 bar)

was observed at 40.95 %, whose compound name

was 9-Octadecenoic acid (C19H36O2). The second

and third places were followed by Hexadecanoic

acid, and 9,12-Octadecadienoic acid recorded their

compositions 37.42% and 12.58%, which were

proportional to the investigations done by authors

[30].

The variation of the volume of the mixture and

the operational pressure was carried out, aiming to

analyze the methyl ester compounds released from

triglycerides after being reacted with methanol as

displayed in Table 3. If compared with the data

shown in Table 2, there are slightly different from

the compositions of each compound obtained. The

change of operational parameters, especially the

volume of mixture and pressure, could influence the

symmetry of the GC/MS spectra slightly since

compounds obtained in the second step were more

diverse.

Compositions of Pure Ethanol-Biodiesel-Water

(Et-BD-W)

Table 4 describes the composition (%v/v) of the

Pure Ethanol, biodiesel, and water in one phase

(stable emulsion) whereby the ethanol volumes are

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varied 8, 7, 7, and 9 mL and conducted at 1-15 bar,

30-150oC for 1 h. To determine the stable emulsion

using a vision method by eyes was easy but resulted

in a high error since measuring the exact volume

could be different in each observation. As shown in

the data in a table that the composition measured

was altered in the specific initial volume of aqueous

ethanol. To minimize the error was conducted four

times by changing the initial volume of aqueous

ethanol.

Table 4. Composition (%v/v) of the Pure Ethanol-Biodiesel-Water in a stable emulsion with an initial

volume of the aqueous ethanol 7 – 9 mL (P = 1-15 bar; T 30-150oC for 1 h)

Et (%)

Volume (mL)

Composition (%)

Aq.Et

0.24

7.76

25.87

73.33

0.80

0.28

6.72

21.00

78.13

0.88

0.35

6.65

17.97

81.08

0.95

0.54

8.46

16.92

82.00

1.08

0.32

7.68

38.40

60.00

1.60

0.35

6.65

20.15

78.79

1.06

0.48

7.52

10.74

88.57

0.69

0.21

6.79

29.52

69.57

0.91

0.28

6.72

19.76

79.41

0.82

0.35

6.65

13.30

86.00

0.70

0.42

6.58

11.54

87.72

0.74

7.33

0.22

7.11

30.49

68.57

0.94

7.33

0.29

7.04

20.50

78.64

0.85

7.00

0.35

6.65

13.30

86.00

0.70

8.00

0.48

7.52

12.97

86.21

0.83

Fig. 2: The ternary system of pure ethanol-biodiesel-water in a stable emulsion whereby POME was synthesis

by employing the near isochoric subcritical esterification mixture V 575 mL; P=1-15 bar for 1h; and T=30-150

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In the first trial, 8 mL aqueous ethanol, 97%

could be dissolved with 22 mL biodiesel in a stable

emulsion. At the same time, volume decreased to 7

and 7.33 mL; the biodiesel needed mixed ideally

was reduced highly to around 16 mL. When

aqueous ethanol concentration declined to 96 %, the

amount of biodiesel mixed increased. By using two

7 mL and 7.33 mL, ethanol 96 %, biodiesel

dissolved were 25, 27, and 27 mL, while 8 mL

ethanol 96 % decreased biodiesel volume to 12 mL.

It was indicative that ethanol and biodiesel acted as

a surfactant.

If using ethanol 97% and transformed into the

composition (%v/v), the composition of pure

ethanol, biodiesel, and water in the first trial was

25.87%, 73.33%, and 0.80% and changed to

17.97%, 81.08%, and 0.95% for ethanol 95%. The

compositions of the third trial for similar ethanol

concentrations were observed at 29.52%, 69.57%,

0.91% and 13.30%, 86.00%, and 0.70 %, which

were comparable to each other. The range of pure

ethanol, biodiesel, and water in all ethanol

concentrations and volumes could be summarized

10.74%-38.40%, 60.00%-88.57%, and 0.69%–1.60

%, respectively. The data disclosed that the water

variations were relatively small. Generally, the less

aqueous ethanol concentration was blended, the

more the amount of biodiesel was added to be a

stable emulsion.

To know and analyze the substances formed in

non- and stable emulsions of the pure ethanol-

biodiesel-water, it was necessary to describe them in

the ternary graph as presented in Fig. 2. The areas

where the aqueous ethanol and biodiesel mixed

entirely becoming stable emulsion were very

narrow. Two ternary diagrams, as shown relatively,

gave a similar trend whereby the equilibrium lines

were located just on the right side of triangles

(before reader). The areas where aqueous ethanol

and biodiesel in the stable emulsion were situated

between the equilibrium line and the right side- and

stretched up to the left side of triangles just below

the corner. Even though the areas are limited for all

ternary systems, the number of composition

combinations of aqueous ethanol and biodiesel was

infinite.

The work invented the addition of biodiesel

continually after Aq.Et-BD substance was formed a

stable emulsion, would not occur a separation of

components. It was different in creating a stable

emulsion of the aqueous gasohol in which it would

not be separated by adding aqueous ethanol

continually, as reported by authors [23].

Compositions of Aqueous Ethanol-Biodiesel-

Diesel (Aq.Et-BD-D)

The presence of diesel on the mixture gave a

composition that was different from previous fuels

whereby four components, pure ethanol-biodiesel-

diesel-water, could be a stable emulsion (Table 5).

In this presentation, the four components were

reduced to be three substances, aqueous ethanol,

biodiesel, and diesel which could be presented in

ternary graphs. In preparation for blended fuels,

biodiesel acted as an important substance to set a

stable emulsion.

In the first step, aqueous ethanol and diesel were

mixed with a specific ratio (v/v), and then biodiesel

was added gradually until a stable emulsion was

formed. At one ethanol concentration, the

proportion of aqueous ethanol to diesel was altered,

as shown in the table. The seven mL of aqueous

ethanol 96 % and diesel could be dissolved entirely

with 23 mL biodiesel in which composition of

Aq.Et, BD, and D were 18.92%, 62.16%, and 18.92

%. The ratio changed to 7:5; the composition was

recorded at 12.73%, 78.18%, and 9.09% that the

biodiesel percentage increased. The volumes of

aqueous ethanol and diesel at 7 and 15 mL mixed

with 63 mL biodiesel resulted in compositions 8.24,

74.12, and 17.65 %.

When ethanol 95 % were employed whose

water content inclined, the composition trends

relatively changed since biodiesel needed to form a

stable emulsion increased. The seven mL of aqueous

ethanol and diesel needed 26 mL biodiesel

increasing from 23 mL (ethanol 96 %). The increase

of biodiesel was to balance the addition of water

content in the mixture and the similar trend shown

by ethanol 94%. Identical as described previously

that in all ethanol concentrations, were found that

the addition of biodiesel continually after a stable

emulsion was formed would not separate the

components.

Figure 3 displays the angular graph of Aq.Et-

BD-D in a stable emulsion whereby ethanol mixed

was 96 % (A) and 95 % (B). If compared with the

ternary diagram of pure ethanol-biodiesel-water, the

equilibrium lines of aqueous ethanol-biodiesel-

diesel were very different since the presence of

diesel. To know the area where the aqueous ethanol,

biodiesel, and diesel in the stable emulsion were by

drawing the straight lines from equilibrium points to

the right (before reader) until the triangular side.

The area of which the lines were passing through

was that the three components formed one phase

substance. The straight lines drawn to the right were

the biodiesel composition increased; bioethanol was

constant, but diesel decreased in which the

components were kept in a stable emulsion. The

equilibrium lines, as shown in the triangular graph,

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could be having similar trends if using ethanol with a concentration of 94 %.

Fig. 3: The ternary system of aqueous ethanol-biodiesel-diesel in a stable emulsion whereby POME was

synthesis by employing the near isochoric subcritical esterification mixture V 575 mL; P=1-15 bar for 1h; and

T=30-150 oC

(ethanol 96 %)

Table 5. Compositions of Aqueous ethanol (Aq.Et.), biodiesel (BD), and diesel (D) in stable emulsion using

ethanol 96%

Volume (mL)

Composition (%)

(%)

Aq.Et

18.92

62.16

18.92

12.73

78.18

9.09

77.92

12.99

8.24

74.12

17.65

17.51

65.00

17.50

11.47

72.13

16.39

8.34

73.81

17.86

7.44

71.28

21.28

15.9

68.18

15.91

10.61

74.24

15.15

7.53

76.34

16.13

3.4 Fuel Parameters

The fuel parameters such as density (), specific

gravity (SG), API, and cetane number (CN) were

measured and analyzed, as displayed in Table 6. The

density and specific gravity of the first sample

(Aq.Et-BD), whereby biodiesel preparation was

conducted at 7 bar, were similar at 0.84 g/cm3 (15

oC) while the rest parameters were not measurable.

The density and specific gravity of the pure

biodiesel were recorded at a similar figure of 0.87

g/cm3.

Meanwhile, API and CN were 29.40 and 62.50.

All parameters could be measured for the mixture of

aqueous fuel ethanol, biodiesel, and diesel (Aq.Et-

BD-D). When the pressure increased to 15 bar, the

specific fuel parameter relatively changed. The pure

biodiesel gave density 0.87, SG 0.87 g/cm3, and

API 29.80, which slightly increased compared to

that of 7 bar.

Similar parameters, as previously described, had

been investigated by authors [31]. They found that

the parameters density, SG, and API of the biodiesel

and emulsion of ethanol, biodiesel, and diesel gave a

comparable result with a present study. At the same

time, the cetane numbers were different, which

could be caused by the various standard employed

[32].

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Table 6. The fuel parameters density, API, and CN of the biodiesel and its blending, Aq.Et-BD (7 bar), Aq.Et-

BD (15 bar), and Aq.Et-BD-D (7 bar) with ethanol concentration 96%

Sample

 (g/cm3 )

SG (15oC)

API (15oC)

Aq.Et-BD

7 bar

0.84

BD 7 bar

0.87

29.40

62.50

Aq.Et-BD (15 bar)

0.84

35.40

BD (15 bar)

0.87

29.80

85.00

Aq.Et-BD-D (7 bar)

0.85

33.50

71.40

API: American Petroleum Institute gravity

Table 7. Viscosity, ASTM Color, flash point, and pour point of the blended fuels aqueous ethanol-biodiesel and

aqueous ethanol-biodiesel-diesel using ethanol 96% (15 bar)

Fuels

Viscosity 40oC (mm2/s),

ASTM

Color

Flash Point (oC)

Pour Point,oC

Aq.Et-BD

3.64

D 1.0

Aq.Et-BD-D

4.29

D 3.0

Fig. 4: The scale of the demonstrative light color of the flame appearing of the fuel-burning issued by ASTM

D1500 standard

The color quantity called ASTM color of the

flame of both fuels was different depending on the

component contained in the fuel. The flame color of

the aqueous ethanol-biodiesel was quantized at

D1.0, which was dominated by yellowish. When

diesel was added into the mixture to be aqueous

ethanol-biodiesel-diesel, the flame color changed

profoundly to D3.0, which started to change,

becoming red. The quantity of flame color of the

fuel was regulated by a standard issued by ASTM

D1500, as shown in Fig. 4. The flashpoint of Aq.Et

was 65 oC and declined to 56 oC for Aq.Et-BD-D

blends meanwhile, the pour points were recorded at

5 and 6 oC that were higher from previous reports

employing diesel-ethanol blends recorded at -36

until -9oC [33]. The pure diesel and biodiesel had

viscosity values around 3.11 and 4.51 mm2/s, as

investigated by authors [34], which were relatively

similar to the present work. If compared to that

study, the flashpoints of the current work were less,

which might be caused by the ethanol presence.

Table 8. The amount of fuels (aqueous ethanol-biodiesel and aqueous ethanol-biodiesel-diesel) evaporated

as temperature increases (Ethanol 96%)

Sample

Test

Aq.Et-BD-D

(oC)

Aq.Et-BD (oC)

IBP

5 %

10 %

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20 %

289

30 %

310

40 %

320

323

50 %

325

60 %

329

328

70 %

334

330

80 %

345

348

90 %

353

FBP

98.00

98.50

Dist. %

0.30

Res mL

FBP: Final boiling point; 10%: 10% of fuel evaporated

It is essential to measure and analyze the

distillation property of the fuel, which is to know the

amount of fuel evaporated concerning the

temperature increase, as shown in Table 8. Two

fuels boiled at a similar point 76oC of which was

called the initial boiling point (IBP). The points

could be belonged by the fraction of diesel fuel,

which had the least boiling point. When 5 % of

those fractions were evaporated, ethanol started to

boil at 78 oC. The amount of ethanol for other fuel

(Aq.Et-BD-D) finished evaporating first compared

to the first fuel (Aq.Et-BD), which had more

alcohol.

The first sample of which ethanol evaporated

entirely at temperature 79oC had disappeared 40 %

while the second sample evaporated a similar

amount at 310oC. When the fuels had evaporated 50

%, the boiling temperatures were relatively close

recorded at 432 and 322oC. The temperatures were

close until the number of fuels transformed into

vapor at 90 %. The final (FBP) boiling points and

residues showed the same figures observed at 353oC

and 0.30 mL. The results of the present study are

comparable with works that used raw material

coconut oil and palm oil employed the sub-critical

and conventional trans-esterification [35, 36].

4 Conclusion

The palm oil methyl ester (POME) was processed

successfully by employing the new technique called

the near isochoric trans-esterification. The methyl

ester compounds obtained were dominated by 9-

Octadecenoic acid (C19H36O2) and Hexadecanoic

acid (C17H34O2), whose composition was 40.95

and 37.42 % conducted at 15 bar for 1h which were

relatively similar for 7 bar. The POME was

blended with aqueous ethanol and diesel, forming

stable emulsions, aqueous ethanol-biodiesel, and

aqueous ethanol-diesel-biodiesel. The higher

ethanol concentration employed > 96 %; the

blended fuels were clear and less of droplets. In

ethanol 94-95 %, the droplets appearing in the

solution increased rapidly but distributed uniformly

throughout the solution. The results showed that the

compositions of aqueous ethanol, diesel, and

biodiesel in stable emulsions were in the range of

7.44-18.92, 9.09-21.28, and 62.16-78.18%. The fuel

parameters of biodiesel and emulsions such as

density, SG, API, viscosity showed a similarity with

the previous works and standards.

Acknowledgments:

The investigators would like to profoundly thank the

Indonesian Ministry of Research and Higher

Education and Sam Ratulangi University for

financial support as well as Professor Benny

Pinontoan as a Dean of Faculty of Mathematics and

Sciences at UNSRAT Manado who provided the

facilities and assisted the authors in conducting the

measurements and experiments. High appreciation

goes to the leader of the Department of Oil and Gas

Engineering, Polytechnic of Energy and Minerals,

Cepu Blora, Indonesia in providing the instruments

and assisting in a fuel parameter analysis.

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Guntur Pasau, Maria Bobanto, Ronny Purwadi, Ramli Thahir,

Bayu Achil Sadjab, Vecky A. J. Masinambow, Tun Sriana, Zami Furqon,

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Guntur Pasau, Maria Bobanto, Ronny Purwadi, Ramli Thahir,

Bayu Achil Sadjab, Vecky A. J. Masinambow, Tun Sriana, Zami Furqon,

Silvya Y. Agnesty, Arief Widjaja

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Sources of Funding for Research Presented in a

Scientific Article or Scientific Article Itself

The investigators would like to profoundly thank the

Indonesian Ministry of Research and Higher

Education and Sam Ratulangi University for

financial support as well as Professor Benny

Pinontoan as a Dean of Faculty of Mathematics and

Sciences at UNSRAT Manado who provided the

facilities and assisted the authors in conducting the

measurements and experiments. High appreciation

goes to the leader of the Department of Oil and Gas

Engineering, Polytechnic of Energy and Minerals,

Cepu Blora, Indonesia in providing the instruments

and assisting in a fuel parameter analysis.

Creative Commons Attribution License 4.0

(Attribution 4.0 International, CC BY 4.0)

This article is published under the terms of the

Creative Commons Attribution License 4.0

https://creativecommons.org/licenses/by/4.0/deed.en

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DOI: 10.37394/232015.2022.18.40

Hanny F. Sangian, Meiga P. Paendong, Joshua R. Rombang, Jil A. Lametige,

Guntur Pasau, Maria Bobanto, Ronny Purwadi, Ramli Thahir,

Bayu Achil Sadjab, Vecky A. J. Masinambow, Tun Sriana, Zami Furqon,

Silvya Y. Agnesty, Arief Widjaja

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