Page 113 - Materials Chemistry, Second Edition

Life Cycle Assessment of Biodiesel from Palm Oil 99

1,000–1,300 fruitlets depending on the plantation management and establishment.
On a per hectare basis, an oil palm plantation can yield averagely 35 t of FFB
(from about 148 palm trees) and 8.6 t of palm oil (Henson 1990; Schmidt 2007).
Generally, the extraction of 1 t of crude palm oil (CPO) requires 5 t of FFB which
produces 1.15 t of EFB and 3.25 t of palm oil mill effluents (POME) as residues
(Corley and Tinker 2003). The harvested FFB may contain around 20 % mesocarp
oil, 25 % nuts (comprising 5 % kernels, 13 % fiber, and 7 % shell), and 23 %
empty fruit bunches. The kernels also contain around 55 % oil and 8 % protein
(Corley and Tinker 2003; Møller et al. 2000).
The oil palm industry now focuses on genetic means of improving the oil yield,
palm disease tolerance, and the height of the tree (breeding dwarf palms in order to
prolong the economic cropping cycle). Corley and Lee (1992) and Pushparajah
(2002) have reported the possibility of commercializing genetically bred oil palms
for the next 15–40 years. However, currently, transgenically high oleic acid palms
have been field tested and proven to give high yields (Ravigadevi et al. 2002).

2 Biodiesel Production from Palm Oil: Process Description

2.1 Oil Palm Cultivation and Harvesting

The production of FFB involves six (6) main processes which are summarized in
Fig. 2. The planning stage involves the feasibility studies of the proposed area for
plantation. Usually, environment impact assessment (EIA) forms part of the
planning stage and the implementation of management measures to assuage the
adverse effects of some social and environmental practices are also considered. Oil
palm nursery proceeds after confirmation of the suitability of area for plantation
which is normally endorsed by respective bodies for development. The seedlings
are raised in polybags as nursery for about a year with adequate irrigation with
manuring, etc. The land for the oil palm plantation is then cleared of vegetation.
Creation of road or paths, water drainage systems, and other soil conservation
measures are put in place before the actual transplant. Most often the vegetation is
cleared by burning which affects the environment negatively. In order to control
soil erosion after the seedlings transplant, leguminous crops are interspersed with
the oil palm trees which further fix nitrogen into the soil. Other field maintenance
practices include pruning, pest and disease control, and mulching. After
24–30 months of transplanting depending on the nutritious value of the soil,
harvesting of FFB may be due (Corley and Tinker 2003). Normally, harvesting is
done manually with chisels and sickles mounted on bamboo or aluminum poles.
The FFB are then transported to the oil mill for oil extraction. In order to ensure
minimal amount of free fatty acid (FFA) content of the oil, handling of FFB after
harvesting must be done in a way to reduce bruises on the fruits. Also, since the
quality of the oil produced depends on the time interval between harvesting and