Environmental Engineering Reference
In-Depth Information
taBle 17.7
Fuel characteristics of cPo, mFo, and Blends of cPo/mFo
method
astm
cPo/mFo
(50:50)
Property
unit
mFo
cPo
Gross heat of combustion
D 240
Btu/lb
kJ/kg
18,350 min
42,680 min
17,064
39,690
17,692
41,150
Sulfur
D 4294
Wt %
3.5 max
0.03
1.55
Viscosity at 50°C
D 445
mm
2
/s
180 max
25.6
67.3
Flash point
D 93
°C
66 min
268
99
Ash
D 482
wt %
0.1 max
NA
0.012
Pour point
D 97
°C
21 max
21.0
-6
Carbon residue
D 4530
wt %
13.0 max
8.5
7.0
Density at 15°C
D 1298
kg/L
0.98 max
0.9140
0.9408
Sediment by extraction
D 473
wt %
0.10 max
NA
0.02
Water by distillation
D 95
vol %
0.5 max
NA
0.25
NA, not available.
These will give rise to coking on the injectors, carbon deposits, oil ring sticking, and thickening and
gelling of the lubricating oil as a result of contamination with vegetable oil.
It is possible to reduce the viscosity of the vegetable oil by incorporating a heating device to the
diesel engine as has been successfully demonstrated by the engine manufacturer, Elsbett (Basiron
and Hitam 1992; Hitam and Jahis 1998). Other factors that may have long-term effects on the
engine are free fatty acids and gummy substances which are found in the crude vegetable oils.
Incomplete combustion residues may cause undesirable deposits on the engine components whereas
the gummy substances may cause filter plugging problems. This will call for more regular and
frequent servicing and maintenance of the engine.
Various blends of crude palm oil (CPO) and palm oil products such as refined, bleached, and
deodorized palm oil (RBDPO); refined, bleached, and deodorized palm olein (RBDPOo) with
medium fuel oil (MFO); and petroleum diesel have been evaluated as boiler fuel and a diesel substitute
(Hitam et al.
2004). CPO was blended with MFO whereas RBDPOo and RBDPO were blended with
petroleum diesel, each at various ratios by volume. The resultant fuel blends, CPO/MFO, RBDPO/
petroleum diesel, and RBDPO/petroleum diesel exhibit superior fuel characteristics compared with
those of the individual blend components (Tables 17.7-17.9) (Basiron and Choo 2004).
Evaluation of CPO/MPO blended fuel for power generation was conducted at the Tenaga Nasional
Berhad (TNB) power station at Prai, Penang. A blend of 20% CPO and 80% MFO was evaluated.
During testing, the boiler hopper area, the flame characteristics, the air heater elements, and flue gas
emissions appeared normal. However, the emission of CO, SO
x
, and NO
x
were reduced. On the basis
of trials and commercial runs using blended CPO and MFO fuels for power generation and steam
production, there are no technical difficulties in boiler operation using these blended fuels. Additionally,
blended fuels were found to be less viscous and thus easier for fuel flow (Basiron and Choo 2004).
Field trials using 19 Malaysian Palm Oil Board vehicles (of various makes) were conducted to
evaluate blends of RBDPOo/petroleum diesel (up to 10% RBDPOo) and RBDPO/petroleum diesel
(up to 5% RBDPO) as a diesel substitute. The highest mileage per vehicle of 400,000 km was
recorded, and no technical problems were reported.
17.14 Palm oIl methyl esters as dIesel suBstItute
Biodiesel has gained much attention in recent years because of increasing environmental awareness.
Biodiesel is produced from renewable resources, and, more importantly, it is a clean-burning fuel
