3.1. Oil palm biomass
Oil palm trees are cultivated in all tropical countries of the
world, originally from South Africa. The fruits of oil palm tree
which are grown in a large bunches (named fresh fruit bunches
(FFB) with around 10–40 kg weight) are used for edible oil production.
Inside the reddish palm fruit, a soft pulp surrounds the seed
known palm kernel. The edible palm oil which is extracted from
the pulp is suitable for cooking, while the kernel oil is employed
in soap production. The fruits of oil palm trees could be harvested
after three years from planting, after 12–13th year the maximum
yield is obtained and then gradually decreases until the end of
the 25th year [51]. Malaysia, located in South East Asia, is a tropical
country with minor fluctuation in the weather temperature due to
its equatorial climate. The annual rainfall in Malaysia (200–
250 cm) is excellent for agricultural activities [52]. Due to these
unique environmental circumstance, Malaysia has become the largest
producer and exporter of the crude palm oil (CPO) in the
world. In 2012, the land area committed to the oil palm plantation
was reported approximately 5 million hectares [53] and it has been
projected that oil palm cultivation would increase to about 5.2
million hectares by the year 2020 [54]. Oil palm biomass as one of
the topped ranked produced fruit crops in the world has great
capability to be employed as the hydrogen feedstock. Its potentiality
is more highlighted by the fact that just 10% of the palm production
is edible oil and the rest 90% is biomass. FFB contains only
21% palm oil, while the rest 23% empty fruit bunches (EFB), 14–15%
fibre, 6–7% palm kernel and 6–7% shell are left as biomass [55]. The
most important residues of oil palm industry is demonstrated in
Fig. 3.
Dedication of around 13% of country’s land to oil palm plantation,
introduced Malaysia as one of the largest producer of palm
oil in the world. The amount of palm solid residue (PSR) fromplantation of oil palm is much larger than other types of produced
biomass in Malaysia. Approximately, 21.625 tonnes PSR is generated
from one hectare of oil palm plantation per annum. This abundant
PSR could be an excellent feedstock for hydrogen production
through thermochemical process. Fig. 4 demonstrates the distribution
of different types of PSR during cultivation and production of
oil palm in Malaysia [56].