2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 60 -
TABLE
I
T
HE BASIC INFORMATION RELATED TO THE CALCULATION OF EACH
COMPONENT IN THE TESTED BIODIESEL
Alcohol content in the tested biodiesel
5.34% wt
Volume of the tested biodiesel in the drum tank
15 L
Density of the tested biodiesel
888 kg/m
3
Density of alcohol
780 kg/m
3
TABLE
II
T
HE CALCULATION OF EACH COMPONENT IN THE TESTED BIODIESEL
Mass of the tested
biodiesel
3
3
888
000 ,1
15
m
kg
m
u ¸¸
¹
·
¨¨
©
§
13.32 kg
Mass of the remained
alcohol
0534 .0 32.13
u
kg
0.711 kg
Volume of the
remained alcohol
3 4
3
10 116 .9
780
711 .0
m
mkg
kg
u
911.6 ml
B. Methodology
The drum tank containing about 15 L of the
unrecovered alcohol biodiesel was set as the feedstock.
The air from gas supply set was introduced to the drum
tank until the pressure reached the set value, then this
high pressure feedstock was push through the filter to
remove the contaminate from the stream. The flow rate of
biodiesel was varied at 18, 20, and 25 L/hr controlled by
the rotameter before it was heat up to the studied
temperature varying at 80, 90, and 100
o
C. At this point
pressure of biodiesel was measured and adjusted by the
gas supply set to reach the studied conditions, in the
range of 3, 5, and 7 bar.
After that, the valve was opened to let the stream flow
through the nozzle and spray inside the flash tank. A part
of the stream will immediately flash into a vapor which is
the more volatile component than the remaining liquid.
Based on this system, alcohol vapor is the more volatile
component will be condensed and storage further, while
the remaining liquid is biodiesel.
C. Alcohol Recovery (%)
The performance of alcohol recovery from the tested
biodiesel was calculated by the following equation.
100
911.6
(ml)
alcohol
flashed of
Volume
(%)
recovery
Alcohol
u
(1)
III. R
ESULT AND
D
ISCUSSION
D. Flow rate
According to Rakwong and Yangtong [5], they
proposed that at 88.5
o
C under the operating pressure of 7
bar is the optimum condition for alcohol recovery. Then
we conducted our experiments based on the previous
work in order to study the effect of the feed flow rate.
The effect of the flow rate on recovery of alcohol from
mixed methyl-ethyl esters using Flash evaporation
technique is shown in Fig. 2.
This figure shows that the alcohol recovery decreases
as the feed flow rate increases. The effect of feed flow
rate is due to the difference in the drop size of the
saturated liquid stream. The higher flow rate generates
the larger drop size of the feedstock resulting in the
decrease of its surface area. The decreased surface area of
the saturated inlet stream causes in the reduction of
alcohol evaporation process.
Flow rate (L/hr)
16
18
20
22
24
26
Alcohol recovery (%)
90
91
92
93
94
95
96
Fig. 2. Effect of flow rate on alcohol recovery.
E. Pressure
Based on the study the effect of flow rate on alcohol
recovery, we found that the optimum feed flow rate of
this system is 18 L/hr. Then the effect of pressure on
alcohol recovery was investigated at the optimum flow
rate.
Fig. 3 illustrates the effect of operating pressure on the
alcohol recovery. The results presented show that the
amount of recovered alcohol increases with increasing
operation pressure. The reason for the increase in the
alcohol recovery with pressure can be explained on the
basis of the increasing of surface area of the tested
biodiesel which is shown in Fig. 4-6. The larger surface
area of the feedstock, the more amount of the recovered
alcohol was obtained.
Pressure (bar)
2
3
4
5
6
7
8
Alcohol recovery (%)
20
30
40
50
60
70
80
90
100
80
o
C
90
o
C
100
o
C
Fig. 3. Effect of pressure on alcohol recovery.
