Scientific Bulletin of the Electrical Engineering Faculty – Year 10 No. 3 (14)
ISSN 1843-6188
USE OF MOLASSES IN BIOFUEL DEVELOPEMENT
Eduard SARBU1, Corina TEIU1, Ioan Calinescu2, Corina TEODORESCU1
1
Constanta,”Ovidius” University, Romania,
Bucuresti,”Politehnica” University, Romania
2
challenges for the next decade. That is the reason why
the European Union has established sustainability
criteria for biofuels production. This criteria includes the
evaluation of biomass sources and the contribution of
biofuels in reduction of gas emissions in the entire life
cycle of biofuels and engine fuels, which contributes to
greenhouse effect. In Europe, the market of biofuels is
regulated by Directive 2003/30/EC on the promotion of
the use of biofuels or other renewable fuels for transport.
This Directive defines goals related to the share of
biofuels in subsequent years. This share in the entire
Community, should be 5.75% in 2010. Additionally, the
European Commission proposed to define the minimum
share of biofuels in the market at 10% in 2020. Plans
also include changes of the fuel quality requirements
valid in Europe, and Directive 98/70/WE. These are
intended to increase the allowable share of biodiesel in
diesel fuel to 7% and then 10% (V/V), and bioethanol in
gasoline to 10% (V/V). Starting from 1st of January
2009, gasoline must contain between share of 2 % vol
biofuels and 4 % .
Ethanol is one of the most important renewable fuels
who contributes to the reduction of negative
environmental impacts. It’s production is a complicated
process and requires the conditioning or pretreatment of
the feedstock for fermenting organisms to convert them
into ethanol. The bioethanol can be produced using
different feedstocks, such as: molasses, starch and
celluloses. Because Romania doesn’t have such vast
cereal cultures, the main use being the food industry, an
optimal option could be the molasses from the sugar-beet
processing.
Abstract: This paper presents the opportunities to enhance
the value of residues like molasses for alternative fuel
production. To aline with environmentally E.U. standards
more and more severe, Romania has the natural resources to
approach a zero-waste goal, represented here by molasses,
and transforming them into bioethanol, used as gasoline
component in the automobile industry. The bioethanol was
obtained by fermenting the molasses using saccharomyces
cerevisiae and for water elimination the water-ethanol
condensate was past trough molecular strainers. Different
mixtures of F.C.C., catalytic reforming gasoline and
bioethanol had being used in this study. Bioethanol is one of
the most important renewable fuels who contributes to the
reduction of negative environmental impacts.
KEYWORDS: molasses fermentation,
cerevisiae, biofuel, bioethanol.
saccharomyces
INTRODUCTION
Because of the decreasing of raw materials for the fuel
industry, searching an alternative option that will be
environmentally friendly has becoming an increasing
concern. To reduce the net contribution of GHGs to the
atmosphere, bioethanol has been recognized as a potential
alternative to petroleum-derived transportation fuels.
Currently, the bioethanol is mostly produced from
cereals, especially from corn, in countries like S.U.A.,
which holds important cultures of corn. In Brazil,
bioethanol for fuel is derived from sugar cane and is
used pure or blended with gasoline in a mixture called
gasohol (24% bioethanol, 76% gasoline) [1]. In several
states of the United States, a small amount of
bioethanol (10% by volume) is added to gasoline,
known as gasohol or E10. Some countries have
exercised biofuel program involving both form
bioethanol–gasoline blend program, e.g. the United
States (E10 and for Flexible Fuel Vehicle (FFV) E85),
Canada (E10 and for FFV E85), Sweden (E5 and for
FFV E85), India (E5), Australia (E10), Thailand (E10),
China (E10), Columbia (E10), Peru (E10), Paraguay
(E7), and Brazil (E20, E25 and FFV any blend) [2].
Ethanol is made from a variety of products such as
grain, molasses, fruit, cobs, and shell; its production,
excluding that of beverages, has been declining since
the 1930s because of the low cost [3].
Since the first studies refer to biofuels production
depending mostly on crops for food industry, to enhance
the value of some residues has becoming a viable option.
The sustainable production of biofuels is one the greatest
EXPERIMENTAL PART
FEEDSTOCKS
Molasses
For bioethanol production, the molasses from sugar-beet
processing was used . The molasses is the final residue
from sugar production, which has no economically
possibility for a further sugar extraction. The quality
specifications of the molasses used for this study are
presented in table 1.
127
Scientific Bulletin of the Electrical Engineering Faculty – Year 10 No. 3 (14)
Molasses from sugar-beet
Quality
Experimental
specifications
Data
20-25
22
75-80
78
44-52
51
Compound
Water, %
Dry matter, %
Total sugar, %
Inverted sugar ,
%
Rafinosses, %
Total nitrogen, %
Mineral matter,
%
pH
STAS
Analyses
(% vaporized)
0
10
20
30
40
0.1-0.5
0.3
0.6-1.8
1.2-2.4
1
2.1
7.6-12.3
10.4
6.0-8.6
6.5
ISSN 1843-6188
Table 1. The chemical composition of the molasses
from sugar-beet
Gasoline components from FCC and CR (platforming)
plants
In tables 2 4 are presented the properties of the
gasoline components used for this study. The CR
gasoline has a high initial boiling point, 50 °C (Table 2),
which creates problems when starting the engine,
specially in the winter. The main properties of the
gasoline components are described in table 3.
CC Gasoline
(0C)
CR Gasoline
(0C)
34
55
57
65
71
50
100
108
113
119
50
60
70
80
90
95
91
110
130
150
171
-
124
130
138
147
158
168
Table 2. STAS Analyses
CC Gasoline
CR Gasoline
Test Method
0.726
0.806
ASTM D 129899(05)
RON
MON
Benzene Content (%)
93.7
82.6
0
96
85.5
0.9
Sulfur Content (ppm)
15
2
Vapour Pressure (Kpa)
Karl- Fischer Water
(ppm)
Aromatics (%)
Copper strip corrosion rating (
3hrs, 500C)
78.44
67.92
120
160
25
64
SR EN ISO 5164:06
SR EN ISO 5163:06
SR EN 14517-05
SR EN ISO 2084604
SR EN 13016-1:01
SR EN 50081-1
01.92
SR EN 14517-05
1a
1a
SR EN ISO 2160-03
Properties
Density d1515
Saccharomyces cerevisiae
Table 3 Characterization of gasoline components
The molasses fermentation process is described in figure 1.
THE TECHNOLOGICAL PROCESS OF
BIOETHANOL PRODUCTION FROM MOLASSES
The process takes place in two steps:
Molasses fermentation process
The anaerobic fermentation of molasses was
made by saccharomyces cerevisiae at laboratory scale, in
a 5 dm3 reactor, with a heating device for temperature
control. The time for the fermentation process was 72 hrs
at a constant temperature of 38 °C. The CO2 effluent
generated in reaction was cooled for condensing the
bioethanol vapors, preventing the lost by evaporation.
The bioethanol quantity has been calculated according to
the following reaction:
C6H12O6
Figure 1 . The fermentation process using a
discontinuous reactor
2 C2H5OH + 2 CO2
128
ISSN 1843-6188
Scientific Bulletin of the Electrical Engineering Faculty – Year 10 No. 3 (14)
1) fermentation reactor;2) heating device;3) cooler;4)
thermocouple.
The bioethanol recovery by distillation and water
elimination
When the fermentation was complete the mixture has
been distillated for the bioethanol recovery. It was used a
distillation column with glass rings filling and a height
of 110 cm, heated all along its height. The heating was
realized to maintain the vapour temperature, to avoid the
precocious condensation of the vapors, before leaving
the column.
Product
Density
d1515
Water
Content
(%)
Acidity
(acetic
acid %
m/m)
pH
Test
Method
ASTM
D4052
ASTM
E203
ASTM
D1613
pH
paper
Bioethanol
0.795
0.5
0.0015
6.5
RON
SR EN
ISO
5164:06
108
Table 4. Properties of the bioethanol obtained
ACHIEVING OPTIMAL MOTOR GASOLINE BLEND
Bioethanol is appropriate for the mixed fuel in the gasoline
engine because of its high octane number [4]. Before
making the blends, it was studied mathematically, based on
properties of different components, witch are the optimal
proportions of each component in the blends.
Thus, it was decided to study 3 of those mixtures, the
proportions of each compound are presented in table 5.
5
Blend 2
(10%
bioethanol)
10
Blend
(15%
bioethanol)
15
40
37.5
35
45
42.5
40
3
7
3
7
3
7
Blend 1
(5% bioethanol)
Compound
Bioethanol (%)
CR
Gasoline
(%)
CC
Gasoline
(%)
Iso C5 (%)
Figure 2. The distillation and water elimination ETBE (%)
process
Table 5. The making of the three types of auto gasoline
1) boiling vessel;2) heating device;3) distillation column
with glass rings filling and heating system;4) thermal
insulation;5) thermometer;6) coolers;7) collecting
vessel;8) molecular strains;9) CaCl2; ICW = input
cooling water; OCW = output cooling water.
The mixture’s distillation was made with a strictly
temperature control to restrict water vaporization
together with bioethanol. The water-ethanol condensate
was past trough a molecular strainer layer and collected
in a container in the presence of CaCl2 for water
adsorption as air humidity. For a better efficiency in
water adsorption, the bioethanol was past trough a
second step for obtaining an anhydrous product, using a
new layer of molecular strainer. The distillation and
water removing are described in figure 2.
RESULTS AND DISCUSSIONS
The fermentation process needs the following the
quantities of the input compounds witch are presented in
table 6.
Compounds
Molasses
C6H12O6
(glucose+fructose)
C2H5OH
Water
Thus, the bioethanol was produced and used for the
studied mixtures.
Molecular weight
(g/mol)
180
Quantity
(g)
1000
510
46
18
3000
Table 6. Quantities of the input compounds
The properties are described in table 4.
The theoretical amount of bioethanol that can be gained
through the fermentation process is given by relation (1):
Tq 
129
mC6 H 12O6 g   MC 2 H 5 OH g / mol  (1)
MC 6 H 12O6 g / mol 
3
Scientific Bulletin of the Electrical Engineering Faculty – Year 10 No. 3 (14)
Tq 
The analyses made according to European standards for fuel
quality (SR EN 228:2008) are presented in the next tables.
510  2  46
 260.66 g
180
Compound
Bioethanol
(theoretical- Tq)
Bioethanol
(experimental- Eq)
In the process of fermentation, followed by the
distillation and the water elimination, 159 g bioethanol
had resulted; of witch 0.5% represents the amount of
water remaining in bioethanol. In conclusion, the pure
bioethanol quantity is Eq =158.21 g. The yield of the
process (fermentation plus distillation) is given by the
relation (2).

ISSN 1843-6188
Eq
158.21
 100 
 100  60.70%
Tq
260.66
Quantity (g)
260.66
158.21
Yield
60.70 %
Table 7. The fermentation process yield
Once the bioethanol, ETBE and i-C5 were added, the
final blends had improved their behavior at reference
temperature distillation.
From the analyses of the 3 final blends, presented in table
8, the density, RON and MON are directly related to the
increasing content of bioethanol. The content of the
aromatics and olefins are in inverse ratio to bioethanol.
(2)
In the following table are presented the results of the
fermentation process, the theoretical and experimental
ethanol in order to present the reaction yield.
Blend 1
Blend 2
(10%
Properties
(5% bioethanol)
bioethanol)
Blend 3
(15% bioethanol)
Test method
0.7622
0.7648
0.7665
ASTM D 129899(05)
RON
98.4
99.5
100.7
SR EN ISO
5164:06
MON
86.1
86.6
87.2
SR EN ISO
5163:06
Benzene content (%)
0.77
0.65
0.67
SR EN 14517-05
Sulfur content (ppm)
8.3
8.5
8.5
Water content
(ppm)
180
220
275
Aromatics (%)
34.2
33.3
32.9
Olefins (%)
4
1.5
1.3
Copper strip corrosion
rating ( 3hrs, 500C)
1a
1a
1a
Density d1515
Table 8. Characterization of the blends:
130
SR EN ISO
20846-04
SR EN 50081-1
01.92
SR EN 14517-05
SR EN ISO 216003
Scientific Bulletin of the Electrical Engineering Faculty – Year 10 No. 3 (14)
ISSN 1843-6188
The evolution of research octanic number with the increasing bioethanol content is represented in figure3.
R ON
102
100.7
99.5
100
98.4
98
96
96
94
93.7
92
90
CC
g a s oline
5 %
bioetha nol
15 %
bioetha nol
Figure 3. Research octanic number related to bioethanol content
[2] Kadiman OK. Crops: beyond foods. In: Proceedings
of the 1st international conference of crop security,
Malang, Indonesia, September 20–23, 2005.
[3] Akpan UG, Kovo AS, Abdullahi M, Ijah JJ. The
production of ethanol from maize cobs and groundnut
shells. AU J Technol 2005;9:106–10.
[4] Kim H, Choi B, Park S, Kim YK. Engine
performance and emission characteristics of CRDI diesel
engine equipped with the WCC and the DOC. Using
ethanol blended diesel fuel.
[5] Rothman H, Greenshields R, Calle FR. The alcohol
economy: fuel ethanol and the Brazilian experience.
London: Francis Printer; 1983.
[6] Balat M. Current alternative engine fuels. Energy
Sources 2005;27:569–77.
[7] Hansen AC, Zhang Q, Lyne PWL. Ethanol–diesel
fuel
blends—a
review.
Bioresource
Technol
2005;96:277–85.
[8] Pimentel D. Ethanol fuels: energy balance,
economics, and environmental impacts are negative.
Natural Resources Res 2003;12:127–34.
[9] Balat M. Global bio-fuel processing and production
trends. Energy Explor Exploit 2007;25:195–218.
[10] MacLean HL, Lave LB. Evaluating automobile
fuel/propulsion system technologies. Prog Ener Combust
Sci 2003;29:1–69.
In: Proceedings of the 15th international symposia on
alcohol fuels (ISAF XV), San Diego,
September 26–28, 2005.
CONCLUSIONS
The bioethanol can be produced using molasses as a raw
material, the process having two advantages: 1) the
processing of waste, which has a positive environmental
impact;2) the production of bioethanol, an important fuel
component of the future.
According to 614/2009 Ordin published in The Official
Gazette, Romania has 104688.8 tons of sugar as a total
production for 2009-2010. Because the molasses
represents~1/3 of the sugar, this means that 34896.3 tons of
molasses will be produced every year. In accordance of a
study of Petro World taken by Energy Business Review, in
2008 Romania had a 1.6 mil tons of gasoline consumption.
If we can introduce a maximum 5 % bioethanol (SR EN
228:2008) we will be needing ~ 80000 tons of bioethanol
and so, a fourth of this quantity may be supplied by
using molasses as raw material. The blends using
bioethanol have good qualities and can be used as
commercial fuels for the automobile industry.
REFERENCES
[1] Oliveria MED, Vaughan BE, Rykiel Jr EJ. Ethanol as
fuel: energy, carbon dioxide balances, and ecological
footprint. BioScience 2005;55:593–602.
131