Environmental Engineering Reference
In-Depth Information
Compared with RBD palm oil and palm stearin, PFAD contains free fatty acids (FFA) in the range
of 70-90%. Additional pretreatment facilities must be incorporated into existing biodiesel plants
to process such oils. With the knowledge and experience gained by handling oil with a high FFA
content in the laboratory and pilot plants (Choo and Goh 1987; Choo and Ong 1989, Choo et al.
1990; Ong et al. 1992), MPOB has further developed a process to produce biodiesel from high-acid
oils, thus improving the production viability of the palm biodiesel plant. (Harrison et al. 2009)
The filter blocking problems in vehicles running with biodiesel blends first surfaced in 2007.
Researchers discovered that this problem was due to the presence of steryl glucosides (Hoed et al. 2008;
Moreau et al. 2008; Lacoste et al. 2009). Since then, ASTM has incorporated a new parameter, the cold
soak filtration test (CSFT), into the revised specification for Biodiesel Blend Stock (B100) for Middle
Distillate ASTM D6751-08. A CFST time of 360and 200 s was set as the upper limit for normal and
low-temperature conditions (at or below -12°C), respectively. MPOB has also developed methods to
improve the CSFT of palm biodiesel to fulfil the requirement set by ASTM through various processes
(Harrison and Choo 2009; Harrison et al. 2009; MPOB unpublished data).
Considering that transportation is one of the highest energy consumption sectors in the country,
and that diesel constitutes approximately 40% of the fuel consumption, the use of renewable and
environment-friendly palm oil methyl esters as a diesel substitute merits serious consideration.
The main benefit derived from such renewable sources of energy is the reduced emission of
greenhouse gases (GHG) such as CO
2
. The production and consumption of palm biodiesel has a
closed carbon cycle, thus there is no net accumulation of CO
2
in the atmosphere. Subsequently,
palm biodiesel production, because of its lower emissions, is in line with the Clean Development
Mechanism (CDM) of 1997 Kyoto Protocol.
Under the terms of 1997 Kyoto Protocol, there is potential financial gain in transacting these
GHG benefits to the palm oil industry under the CDM. This mechanism allows emission reduction
projects to be implemented, and credits are awarded to the investing parties. Financial incentives
such as an attractive carbon credit scheme could further enhance the economic viability of these
renewable fuels.
17.15 conclusIons
The progressive escalation of energy shortages and fuel prices in recent times has led to an intensified
search for viable alternative sources of energy globally. As conventional energy resources become
more difficult to obtain, efforts must be directed toward developing alternative energy sources.
The palm oil industry is bestowed with a plentiful supply of co-products that can be readily and
easily be used as energy resources. When EFB and biogas are properly processed using proven and
innovative techniques, a considerable amount of energy can be economically recovered. The use of
these co-products from palm oil mills, if implemented by the respective authorities, could help ease
these escalating energy shortages. To this end, the production and application technologies have
been fully demonstrated.
The energy needs of palm oil mills are met for free. Fiber and shell together can supply more
than enough energy to meet their energy demands, with the electricity generated representing
approximately 2% of the national electricity demand. Energy from biogas and EFB has so far been
ignored, although they represent a hefty 4% of the national energy demand in terms of electricity.
Efforts are being made to encourage palm oil mills to sell this excess energy in the form of electricity
to the national grid.
Palm oil methyl esters have been fully evaluated as a potential diesel substitute and a diesel/
cetane improver. Low pour point palm biodiesel that can meet stringent winter diesel specifications
has also been produced. The palm biodiesel is an environmentally benign fuel substitute in terms
of exhaust gas emission. Blends of CPO/MFO and RBDPOo/diesel have also been evaluated as
potential fuel for boilers.
