2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 71 -
and monitored by adjusting flow rate of cooling water
and by using the digital thermometer, respectively.
Temperature is recorded periodically throughout the
experiments.
D. Chemical Analysis
The final reaction solution was partially sampled about
30 mL to suddenly wash with warm water, in order to
stop the reaction and get rid of all contaminants such as
ethanol, gum and sulfuric acid. Washing step was
repeated until washing water had pH of 6-7. The clean
sample would subsequently determined amount of free
fatty acid (FFA) by titration method (AOCS method Ca
5a-40).
E. Data Analysis
The results (%FFA) of each run were analyzed by
using principle of Smaller-The
–
Better and then
respectively calculated and operated as following steps;
(1)
The overall experiment average (T): T =
¦
y
i
/n
(2)
Mean response of each factor for each level such
as A1 = (
¦
y
A1
)/4
(3)
Establish response table using mean response of
each factor and level and response graph
(4)
Effect of each factor, Delta (
'
) = Max-Min
(5)
Re-order the significance of each factor
(6)
Select target level of the significant factor
(7)
Check interaction by plotting maximum and
minimum of each couple factors. If they have an
interaction, it will be intersected.
(8)
Define the predicted FFA, using prediction
equation (
P
)
(9)
Conduct the confirmation run
IV. R
ESULTS AND
D
ISCUSSIONS
The results of each run provided raw yield of FFA (%)
which be adjusted water content before using as a quality
characteristic (y). The water content in washed sample is
1.4 % by wt. of sample. The results of the first and
second stages were shown in table III and V, respectively.
TABLE
III
R
ESULTS OF THE FIRST STAGE EXPERIMENT
Run No.
Factors
y
(%FFA)
A
B
C
D
E
1
1
1
1
1
1
5.34
2
1
2
2
2
2
4.78
3
1
3
3
3
3
3.27
4
1
4
4
4
4
1.77
5
2
1
2
3
4
2.59
6
2
2
1
4
3
3.58
7
2
3
4
1
2
4.54
8
2
4
3
2
1
4.46
9
3
1
3
4
2
1.72
10
3
2
4
3
1
3.06
11
3
3
1
2
4
3.47
12
3
4
2
1
3
3.66
13
4
1
4
2
3
0.74
14
4
2
3
1
4
1.03
15
4
3
2
4
1
2.27
16
4
4
1
3
2
2.89
Average, T
3.07
Conf. run
4
1
4
4
4
1.15
TABLE
IV
R
ESPONSE TABLE OF THE FIRST STAGE EXPERIMENT
Level
A
B
C
D
E
1
3.79
2.60
3.82
3.65
3.79
2
3.79
3.11
3.32
3.36
3.48
3
2.98
3.39
2.62
2.95
2.81
4
1.73
3.20
2.53
2.34
2.22
Delta
2.06
0.79
1.29
1.31
1.57
Order
1
5
4
3
2
Select
A4
B1
C4
D4
E4
P
= T+ (A4-T) + (E4-T) + (D4-T) + (C4-T)
P
= A4+E4+D4+C4-3T
P
= 1.73+2.22+2.34+2.53-3(3.07) = -0.39
Fig. 2. The response graph of the first experiment
TABLE V
R
ESULTS OF THE SECOND STAGE EXPERIMENT
Run No.
Factors
y
(%FFA)
A B C AxC D AxD E
1
1
1
1
1
1
1
1
1.41
2
1
1
1
2
2
2
2
0.96
3
1
2
2
1
1
2
2
1.41
4
1
2
2
2
2
1
1
1.21
5
2
1
2
1
2
1
2
0.66
6
2
1
2
2
1
2
1
1.10
7
2
2
1
1
2
2
1
0.46
8
2
2
1
2
1
1
2
0.61
Average, T
0.98
Conf. run 2
2
1
2
2
0.47
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
1
2
3
4
Level
FFA (%)
A (Cat)
B (Amp)
C (Ratio)
D (Temp)
E (Time)
