Effect of %loaded of catalyst
FFA conversion may also be increased by the use of higher concentration of the
catalyst. To explore this possibility, the effects of the concentration of catalyst
on FFA conversion were investigated at 95ºC, and the results are shown in Fig.1.
A feedstock to methanol molar ratio of 1:12 was used. Three different %loaded
of catalyst ( activated carbon loaded with 10, 20 and 30 wt% ferric sulfate as a
solid acid catalyst). Amount of catalyst is 24 %(wt/wt of PFAD) and reaction
time of 2 h were also used in the investigation. As shown in Fig.1. The
conversion of biodiesel increased from 64.66 to 81.12 % when the catalyst
loaded was increased from 10 to 20% within 2 h of reaction. Therefore 20% of
ferric sulfate loaded on activated carbon was assume to be optimal condition and
was used in further investigation.
FIGURE1 Effects of %loaded of catalyst on FFA conversion.
Effects of amount of catalyst on FFA conversion
Fig.2. shows the effect of the amount of activated carbon loaded with ferric
sulfate on FFA conversion. The operating parameter is temperature 95ºC, molar
ratio of PFAD to methanol 1:12, reaction time 2 h and activated carbon loaded
with 20%wt ferric sulfate as solid acid catalyst. When 40 %(wt/wt of PFAD) of
catalyst was add, 88.55% of FFA was converted into FAME in 2 h. However,
when the amount of catalyst exceeded 40 wt% the rate of reaction increased very
lightly.
Effect of mole ratio of PFAD to methanol on FFA conversion
An excess of methanol is necessary for the esterification of FFA with methanol
because it can increase the rate of methanolysis [8]. In this study, varying molar
ratio (1:1-1:14) of PFAD and methanol were reacted in the precence of activated
carbon loaded with 20 wt% of ferric sulfate at 40 %(wt/wt of PFAD) at 95ºC for
2 h and the result are shown in Fig.3. The percentage conversion of FFA
increase from 1:1 to 1:12. The more was the excess of methanol added, the
higher was the conversion of FFA to FAME in the same reaction time. However,
when the ratio was over 1:12, the increment of conversion was relatively slow.
0