Fig. 1. The experiment in this study.
there are 5 holes to insert temperature probes as in
Fig.2.
The study was started by heating 4 kilograms of
biomass with burning charcoal until the average
temperature of gasifier reached 600 ºC. Then 15
kilograms of biomass were top loaded to the gasifier and
the lid was closed. Volume of air entered into the system
was measured by air flow meter, hot wire type. Once the
gas flew out to burner head, which was tested by flame,
wait until the temperature of gasifier was steady then the
gas was sampling and analyzed with gas chromatography.
C. Equations
The equivalence ratio is defined to reflect the
combined effect of airflow rate, rate of Napier Pakchong1
pellet supply and duration of the run.The equivalence
ratio for each run is calculated by[4].
ER =
air
fuel
Actual
air
fuel
tric
Stoichiome
(1)
The stoichiometric calculated from ultimate analysis
is 4.467 kg air/kg Napier Pakchong1 pellet.
The higher heating value of produced gas was
calculated
by
substituting
the
percentage
volumecomposition of CO, H
2
and CH
4
in standard
temperature and pressure (STP
). [5]
HHV (
3
) = (
)13.1 + (
2
)13.2 + (
4
)41.2
(2)
Fig. 2. Schematic diagram of an Imbert downdraft biomass gasifier.
R
ESULTS AND
D
ISCUSSION
A. Biomass characteristics
Fig.3 shows photograph of Napier Pakchong1 grass
pellets. Table II shows result of proximate and ultimate
analysis [6] of produced pellets. There is a relation
between humidity of biomass pellets and volatile
substances. The lower humidity effects higher volatile
content or in other words biomass is more flammable. If
the volume of ash is high, it effects the running process of
gasifier. Table III shows pellets comparison gross caloric
value (HHV). The HHV of Napier Pakchong1 grass
pellets is 18 MJ/kg, which is greater than commonly used
biomass, rice husk, in Thailand.
Fig. 3 Picture of Napier Pakchong1 grass pellet.
TABLE II
PROXIMATE, ULTIMATE AND HIGHER HEATING VALUE ANALYSIS OF NAPIER PAKCHONG1 GRASS PELLET.
Proximate Analysis (% by weight by basis)
Moisture
Ash
Volatile matter
Fixed carbon
HHV (MJ/kg)
7.72±0.14
8.34±0.17
74.78±0.98
9.15±0.93
18.31
Ultimate Analysis (% by weight by basis)
Carbon
Hydrogen
Oxygen
Nitrogen
Sulphur
38.94
4.80
0.73
47.45
0.08
TABLE III
COMPARISON GROSS CALORIC VALUE OF PELLETS FROM
DIFFERENT SOURCES
2013 International Conference on Alternative Energy in Developing Countries and Emerging Economies
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