Oil palm ash as solid catalyst for palm oil-based transesterification to biodiesel
Loading...
Date
2009
Authors
Chin, Lip Han
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Biodiesel is an alternative fuel for diesel engines that is gaining attention in
terms of the depleting fossil fuel resources of the world and the mitigating of
greenhouse effects due to carbon dioxide. In a conventional process for biodiesel
production, triglycerides in oils are converted to biodiesel by using homogeneous
catalyst. However, replacement of the homogeneous catalysis with a heterogeneous
route has received much attention since the process can be simplified by facilitating
the catalyst separation and purification steps. Hence, introduction of a solid
heterogeneous catalyst in biodiesel production could reduce its price, also becoming
competitive with diesel from a financial point of view. Therefore, this study aims to
investigate the feasibility of oil palm ash (OPA), a waste material from oil palm mills
which contains high weight percent of potassium, as solid catalyst for palm oil-based
transesterification to biodiesel. Transesterification of cooking palm oil (CPO), waste
palm oil (WPO) and palm kernel oil (PKO) to biodiesel was studied in a batch
process and the reaction was carried out at 10 bars. OPA catalyst was characterized
by scanning electron microscopy, energy dispersive X-ray, surface area and fourier
transform infrared spectrometry. Response surface methodology was used to study
the effect of reaction time, methanol to oil molar ratio, reaction temperature and
amount of catalyst on the transesterification and the effects of five-level-four factors
as well as their reciprocal interactions were assessed. The effect of reaction time was
found to be not significant for the transesterification of CPO and WPO, but
significant for the transesterification of PKO. The optimum conditions obtained for
transesterification were 0.5-1.19 h, 6.26-18, 60-175oC, 1.67-8.22 wt%, respectively
for reaction time, methanol to oil molar ratio, temperature and amount of catalyst for
transesterification of CPO, WPO and PKO. The optimum biodiesel yields of
89.90±10%, 60.07±10%, 67.53±10% were found for CPO, WPO, PKO, respectively.
Moreover, the OPA solid catalyst proves to be effective in producing the appropriate
quality of biodiesel as per the ASTM specification. The results indicate that OPA can
be used in biodiesel production as a low cost solid base catalyst.
Description
Master
Keywords
Chemical Engineering , Oil palm ash , Biodiesel