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Combustion Characteristics of High-Density
Briquettes Produced from Sawdust Admixture and
its Performance in Briquette Stove
Bello R. S & Onilude M. A.
University of Ibadan, Nigeria
ABSTRACT
Combustion characteristics of high-density briquettes produced from sawdust admixture at three moisture
contents of 12%, 10%, and 8% using screw press extruder was investigated in this work. The briquettes were
burnt in free air and developed briquette stove and the combustion characteristics data collected and
analyzed. The burn characteristics investigated include ignition time, total burning time, mass reduction,
normalized burn rate, the effects of density on briquette characteristics, and stove performance. The results
indicated that briquettes’ self-ignition time in open air and stove was slow, however, burns with a steady
flame. High density of the briquette was responsible for slow flame propagation resulting in a longer time to
burn out while lower density briquettes reach the burning phase faster than higher-density briquettes. The
normalized burn rate increases with an increase in briquette density. The stove performance characteristics
most depend on the quality of fuel material. There is an inverse relationship between specific fuel combustion
and thermal efficiency of the stove. The specific fuel consumption increases with decrease in moisture
content. From these results, the higher the briquettes particle moisture, the higher the specific fuel
combustion and the lower the stove thermal efficiency and vice versa.
Keywords: b
riquette, high-density, extruder, burn rate, normalized, thermal, efficiency.
Classification: FOR Code : 299902
Language: English
LJP Copyright ID: 925625
Print ISSN: 2631-8490
Online ISSN: 2631-8504
London Journal of Research in Science: Natural and Formal
Volume 20 | Issue 3 | Compilation 1.0
465U
© 2020. Bello R. S & Onilude M. A. This is a research/review paper, distributed under the terms of the Creative Commons
Attribution-Noncom-mercial 4.0 Unported License http://creativecommons.org/licenses/by-nc/4.0/), permitting all noncommercial use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Combustion Characteristics of High-Density
Briquettes Produced from Sawdust Admixture and its
Performance in Briquette Stove
Bello R. S. α
& Onilude M. A. σ
____________________________________________
Combustion characteristics of high-density
briquettes produced from a screw press extruder
using sawdust admixture at
three particle
moistures of 12%, 10%, and 8% was investigated
in this article. The briquettes produced were
burnt in free air and briquette stove while the
combustion data collected was analyzed. The
combustion characteristics investigated include
ignition time, total burning time, mass reduction,
and burn rates. The effects of particle moistures
and briquette density on stove performance were
also evaluated. The results show that self-ignition
time and flame propagation for each briquette in
open air and the stove was slow. Briquetes from
lower particle moisture reach the burning phase
faster than higher particle moisture briquettes.
The normalized burn rate for all briquettes
increased with an increase in density. The
specific
fuel consumption increases with
decrease in particle moisture. At higher particle
moisture, the specific fuel combustion reduces
and vice versa for all briquettes. This result is
indicative of an inverse relationship between
specific fuel combustion and stove thermal
efficiency.
Keywords: Briquette, high-density, extruder, burn
rate, normalized, thermal efficiency.
Author
α: Department of Agricultural &
Bioenvironmental Engineering Technology, Federal
College of Agriculture Ishiagu, Nigeria
σ: Department of Wood Products Engineering,
University of Ibadan, Nigeria
© 2020 London Journals Press
I.
INTRODUCTION
Among the several energy resources available,
fossil fuel remained the most exploited resource
in today’s technological world. Economic growth,
urbanization, population increase, and global
energy needs have led to overdependence and
increased demands on the use of fossil fuels,
which consequently had contributed to the
outrageous increases in fuel prices in developing
countries of Africa and Asia, especially in Nigeria.
This increasing trend of fossil fuel prices coupled
with worsening effects of global warming have
prompted the exploration of alternative sources of
energy such as wood and briquettes (Lim, 2007).
However, these resource-based materials are
under pressure from both human activities and
natural factors, including draught.
According to a 2010 report of the Energy
Commission of Nigeria, Nigeria, as of 2010, was
consuming about 43.4 x 109 kg of fuel-wood
annually (Ajiboye et al., 2016) with an average
daily consumption of about 0.5 to 1.0 kg of dry
fuel-wood per person (Olorunnisola, 2007). This
invariably made the demand for fuel wood to have
risen to about 213.4x103 metric tons, while the
supply would have decreased to about 28.4x103
metric tons by the year 2030 (Adegbulugbe,
1994). The complete reliance on the use of wood,
which, is on the increase on daily basis especially
in the less technologically developed countries of
the world as stated by Aremu and Agarry (2013),
for industrial and domestic cooking would not
solve the present energy crisis; rather it would
lead to deforestation or desertification resulting
in further scarcity of this resource (Salunkhe, et
Volume 20 | Issue 3 | Compilation 1.0 79
London Journal of Research in Science: Natural and Formal
ABSTRACT
London Journal of Research in Science: Natural and Formal
al, 2012). As noted by Olorunnisola, (2007), this
should, of necessity be characterized by a
departure from the present subsistence energy
usage levels, to more sustainable and diversified
energy options such as densification into
briquettes.
Different raw material properties produce
different conditions during the densification
process, and this causes differences in the final
quality of the products (Qian et al., 2013, Križan
et al., 2015). It is necessary, therefore, to
characterize these material properties to know out
their optimal factor for densification. It is equally
important to determine the impact of the
technological and material variables: raw material
parameters; technological process; and structural
variables (Križan et al., 2015), known to grossly
affect the final quality of the briquettes.
Variability in biomass materials and structural
requirements have made applicable technological
processes and machines used in high-density
briquette production defer. The utilization of
high-pressure technologies in the densification of
loose materials and their use in boiler furnace
chambers for remote industrial and domestic
heating are strong reasons to study their
combustion
characteristics
and
increased
applications (Risović et al., 2008).
Chin and Siddiqui, 2000 and Faizal et al, (2011)
gave a good review of research works on the
combustion characteristics of biomass. Husain et
al, (2002)
documented the combustion
characteristics
of
low-density
briquettes
containing fiber and shell residues in 60:40 ratio
using 10% starch (of the weight of residues) as
binding agent. Li (2003) investigated the ignition
temperature of coal briquette with plastic
(polyethylene) addition and found that the ignition
temperature decreased from 413 to 373°C when
plastic was added. Currently, there are relatively
few published works on the combustion
characteristics of high-density briquettes produced
from sawdust admixtures and its effect on
different property behaviours compared to its low
and medium-density briquettes. In producing high
quality
briquettes,
several
combustion
characteristics such as burning rate, fuel
consumption rate, smoke generation, flame
propagation, ignition time, gross calorific values,
and heat release values among others are required.
However, the majority of these studies were
extensively carried out and reported for low and
medium-density (using manual or piston press
technologies). However, the present level of
literature and data are not sufficient to fully
exploit the full potential of high-density briquettes
from sawdust admixture. Consequently, more
studies are required for its characterization. This
work investigates the
novel combustion
characteristics of briquettes produced from
composite
sawdust
under
steady-state
experimental conditions.
II.
MATERIALS AND METHOD
Briquette samples: In this study, samples of
high-density briquettes (Figure 1) produced from
sawdust admixture at 12%, 10%, and 8% particle
moistures using a screw press extruder.
Briquette stove: As noted by Bello et al., (2013),
the effects of smoke around the cooking
environment
make
existing
stoves
environmentally unfriendly and uncomfortable
during cooking. Therefore, a focused effort on
stove design and technology, and other factors
needed to deliver the health and climate benefits
associated with reducing the emissions and
improving the health of citizens and their
economic and social impacts (Bello et al., 2013)
necessitated the development and testing of an
updraft high-density briquette/ biomass stoves
(Bello et al., 2019).
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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III.
METHODOLOGY
A measured quantity of briquettes was burnt and
two recommended performance tests: (water
boiling test (WBT) and controlled cooking test
(CCT)) to evaluate quantitative and qualitative
information
about
the
fuel combustion
characteristics and stove performances(Stewart,
1987) .
Water boiling test (WBT): Dry weights of
experimental materials like pot and stove were
taken and recorded. The pot was filled with an
initial known weight of water and the same weight
was maintained throughout the course of the
experiment. The water temperature data was
recorded at intervals of five (5) minutes until the
moment the water came to a vigorous boil.
Controlled cooking test (CCT): Controlled
cooking test was carried out with rice and yam
and the performance characteristics of the
briquettes in the stove. When the cooking was
properly done, the mass of the cooked yam and
time to achieve cooking were recorded with the
aid of a stopwatch.
Statistical analysis tools and models: Statistical
analysis was carried out to verify the significance
of the variations in the selected briquettes. The
model parameters were estimated using SPSS
16.0 program (Release 16.0.0 for Windows) and
Excel (Microsoft Corp., 2003) software to
establish relationships between briquette burn
characteristics. The effects of briquette density
and moisture content on the burn characteristics
of the briquette was done to determine the level of
significance of each parameter on measured
variables.
Correlation analysis was used to examine the
relationship among the variables to provide a
standard index of variability between the
correlation coefficients. Regression analysis was
also carried out to establish the relative
contributions of briquette density, and material
moisture in the prediction of the combustion
characteristics of each briquette. The results of the
unstandardized (β) and standardized Beta (B)
regression coefficients, multiple correlation
coefficient (R), adjusted R2, and its associated p
values for each of the variables that suggest
whether the generated regression model is a good
predictor of briquettes’ properties or not
013) were determined.
(Mitchual et al., 2
London Journal of Research in Science: Natural and Formal
Figure 1: Briquette samples and stove used for the test
Performance test variables and equations: The
variables used in the calculation of stove and
briquette parameters were based on the approach
used by FAO (1990), Ahuja et al. (1997) and
Olorunisola (1999). Four sets of variables used in
the evaluation of test procedures are as follows:
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
Briquette Stove
© 2020 London Journals Press
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81
i.
Briquette burn rate: The procedure for the determination of briquette burn rate employed by
Onuegbu et al. (2012) and Bello et al. (2015) was adopted in the experiment. Briquette sample of
known weight was ignited with a burner and the weight loss measured every 10 seconds throughout
the combustion process using a stopwatch until constant burnt weight was obtained. The weight
loss at specific time was computed from the expression:
Burn rate = Total weigℎt of burnt briquette (kg)/Total time taken (hr)
1
London Journal of Research in Science: Natural and Formal
ii Time spent in cooking per kilogram of cooked food (Ts):
Ratio of time spent in actual cooking to
the total weight of the cooked food.
Ts = Total time spent in cooking (hr)/Total weight of cooked food (kg) (hr/kg)
2
iii Specific fuel consumption: Specific fuel consumption is defined as the amount of solid fuel
equivalent used in achieving a defined task divided by the weight of the task. It can be expressed as:
P HU = M ass of f uel consumed/T otal mass of cooked f ood
3
iv Thermal efficiency ( η ): Thermal efficiency is a measure of the proportion of the total energy which
is gainfully employed in any thermody-namic system. This is a ratio of the work done by heating and
evaporating water to the energy consumed by burning wood. According to Clarke (1985) the thermal
efficiency of a cooking stove depends largely on how well the heat generated is transferred from hot gas
fuel line to the pot or vessel on the stove (convective heat transfer). Thermal efficiency is calculated
from the percentage heat utilized (PHU) given by:
4
ηth(100%) = B urn rate x P HU
IV.
RESULTS
4.1 Briquette burning characteristics
Free air and stove combustion tests were used to
determine the briquettes burn characteristics.
Each briquette was ignited by lighter and
supplemental fuel (kerosene) enough to ensure
the whole of the surface of the briquette was
ignited simultaneously. Figure 2 shows the
different stages of combustion processes from
ignition to burnout. Figure 2(a) is the ignition
phase, fire establishment can be observed burning
around the briquette, Figure 2(b) & (c) are phases
in the flaming combustion stage (d), is at the end
of flaming combustion (burnout), and finally, in
stage (e), there is no flame and the briquette
decomposes purely by char combustion.
Figure 2: Flame propagation of briquette in stove combustion chamber
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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After igniting the lighter was removed, the
combustion proceeded with flame heights of up to
46 cm. From this preliminary observation, it was
evident that the designed combustion chamber
could contain the flame height within the
chamber as seen from Figure 2.
.2 Briquette mass reduction rate
4
Table 1 shows the rate of each briquette reduction
by mass consumed during burning. Mass loss was
recorded for each briquette burnt at intervals until
the mass of the briquette was 5% of its initial mass
(Chaney, 2010).
Table 1: Mass of materials consumed in stove and normalized mass
Mass of Fuel (kg)
Normalized Mass
Briquette Length (m)
12%
10%
8%
12%
10%
8%
12%
10%
8%
0.00
1.05
1.09
1.60
1.00
1.00
1.00
0.90
0.90
0.90
0.17
0.96
1.01
1.49
0.91
0.93
0.93
0.78
0.74
0.70
0.33
0.88
0.90
1.40
0.84
0.83
0.88
0.67
0.62
0.59
0.50
0.76
0.78
1.27
0.72
0.72
0.80
0.52
0.47
0.45
0.67
0.62
0.66
1.16
0.50
0.61
0.73
0.47
0.38
0.32
0.84
0.47
0.57
1.08
0.45
0.52
0.68
0.38
0.27
0.21
1.01
0.34
0.45
1.0
0.32
0.41
0.63
0.28
0.22
0.15
4. 3 Effect of density on NBR
The impact of mass-volume reduction on density is shown in Table 3 to find relationships between
reduced mass and density of all test samples.
Table 3: Effect of mass-volume reduction on briquette density
Time (hr)
Mass of fuel (kg)
12%
Reduced volume of briquette
10%
8%
12%
London Journal of Research in Science: Natural and Formal
Time
(hr)
Reduced density of briquette
10%
8%
12%
10%
8%
0.00
1.00
1.00
1.00
1.49
1.49
1.49
0.71
0.73
1.07
0.17
0.91
0.93
0.93
1.29
1.22
1.16
0.74
0.83
1.29
0.33
0.84
0.83
0.88
1.11
1.02
0.97
0.79
0.88
1.44
0.50
0.72
0.72
0.80
0.98
0.78
0.74
0.78
1.00
1.72
0.67
0.50
0.61
0.73
0.82
0.63
0.53
0.76
1.05
2.19
0.84
0.45
0.52
0.68
0.63
0.45
0.45
0.75
1.27
2.40
1.01
0.32
0.41
0.63
0.46
0.36
0.25
0.74
1.25
4.00
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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4.4 Briquette performance characteristics in stove
London Journal of Research in Science: Natural and Formal
The briquette was tested in a special briquette
stove to determine the variations in time required
to raise water temperature to 100 ° C in water
boiling test (WBT) and time taken to boil specific
quantity of food in controlled cooking test (CCT)
Figure 3: Water boiling and cooking test setups
4.5 Briquette burn rate determination in boiling water (WBT)
The summary of results of water boiling test (WBT) and controlled cooking tests (CCT) using each
briquette sample in order to determine briquette consumption (burn rate) in briquette stove is
presented below in Table 4 and 5. The controlled cooking tests (CCT) were conducted under various
conditions for two varieties of food; rice and yam, respectively were presented in Table 5.
Table 4: Water boiling test (WBT) performance results
Parameter
12%
10%
8%
Time before fuel reaches steady burning (min)
3.35
7.23
2.32
Time spent to boil 1.5kg of water to 100 ⁰ C (hr)
0.14
0.09
0.07
Total time spent for total fuel combustion (hr)
0.69
0.90
Mass of consumed fuel (kg)
1.62
0.78
1.09
Burn Rate (kg/hr)
2.35
1.34
1.17
1.05
Table 5: Controlled cooking test (CCT) performance results with rice and yam
Parameters
Initial mass of raw food (kg)
12%
1.00(1.00)
10%
1.00(1.00)
8%
1.00(1.00)
Final mass of cooked food (kg)
2.39(2.33)
2.38(2.45)
2.40(2.35)
Initial mass of fuel before cooking (kg)
1.60(1.60)
1.09(1.09)
1.05(1.06)
Final mass of fuel after cooking (kg)
0.60(1.04)
0.40(0.40)
0.71(0.43)
Mass of consumed fuel (kg)
1.00(0.56)
0.69(0.69)
0.34(0.62)
Total time spent for cooking (hrs)
0.66(0.39)
0.62(0.34)
0.54(0.31)
Burn Rate (kg/hr)
1.52(1.44)
1.11(2.03)
0.6(2.00)
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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84 Volume 20 | Issue 2 | Compilation 1.0
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The briquette was tested in a special briquette
stove to determine the variations in time required
to raise water temperature to 100 ° C in water
boiling test (WBT) and time taken to boil specific
quantity of food in controlled cooking test (CCT)
Figure 3: Water boiling and cooking test setups
4.5 Briquette burn rate determination in boiling water (WBT)
The summary of results of water boiling test (WBT) and controlled cooking tests (CCT) using each
briquette sample in order to determine briquette consumption (burn rate) in briquette stove is
presented below in Table 4 and 5. The controlled cooking tests (CCT) were conducted under various
conditions for two varieties of food; rice and yam, respectively were presented in Table 5.
Table 4: Water boiling test (WBT) performance results
Parameter
12%
10%
8%
Time before fuel reaches steady burning (min)
3.35
7.23
2.32
Time spent to boil 1.5kg of water to 100 ⁰ C (hr)
0.14
0.09
0.07
Total time spent for total fuel combustion (hr)
0.69
0.78
0.90
Mass of consumed fuel (kg)
1.62
1.09
1.05
Burn Rate (kg/hr)
2.35
1.34
1.17
London Journal of Research in Science: Natural and Formal
4.4 Briquette performance characteristics in stove
Table 5: Controlled cooking test (CCT) performance results with rice and yam
Parameters
Initial mass of raw food (kg)
12%
1.00(1.00)
10%
1.00(1.00)
8%
1.00(1.00)
Final mass of cooked food (kg)
2.39(2.33)
2.38(2.45)
2.40(2.35)
Initial mass of fuel before cooking (kg)
1.60(1.60)
1.09(1.09)
1.05(1.06)
Final mass of fuel after cooking (kg)
0.60(1.04)
0.40(0.40)
0.71(0.43)
Mass of consumed fuel (kg)
1.00(0.56)
0.69(0.69)
0.34(0.62)
Total time spent for cooking (hrs)
0.66(0.39)
0.62(0.34)
0.54(0.31)
Burn Rate (kg/hr)
1.52(1.44)
1.11(2.03)
0.6(2.00)
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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5.6 Stove performance evaluation
The performance of the stove was evaluated by determining its specific fuel consumption (SFC)
and thermal efficiency and the result presented in Table 6.
Table 6: Performance evaluation of each briquette parameters
Parameters
London Journal of Research in Science: Natural and Formal
IIV.
12%
10%
10%
Specific fuel consumption (SFC)
0.75
0.68
0.61
Thermal Efficiency (TE) (%)
34.56
52.64
64.38
DISCUSSIONS
Briquette burning characteristics: Briquette
self-ignition time in open air and stove was low,
but when supported with little quantity of
kerosene, it burns with a steady flame. Each
briquette retained its shape during burning and
did not expand, hence lasts significantly longer
compared to medium or low-density briquettes.
The flame characteristics of the burning briquette
revealed a progressive smoldering within the
briquette hole, followed by a growing yellow flame
at the periphery and simultaneous blue flame
within the center hole. This flame propagates into
high yellow flame with a brilliant white flame at
the center and glowing flame at the surrounding.
As the briquette burns out, the flame degenerates
and gradually dies off as char combustion set-in.
Briquette mass reduction rate: Briquettes with
lower burn rates have better performance than
those of high burn rates which burn out within a
short time.
The gradients of the steady-state combustion
phase for each briquette were plotted to nd the
normalized burn rate (NBR) for each briquette
according to equation 5 is shown in Figure 4.
NBR = Be–þX
5
Where
x = the density in kg/m3
B = exponential frequency factor is a function of
briquette burn time in hours.
þ= constant determined for briquette by a
least-squares t of Equation 5.
The exponential equations for each of the lines
are: For 12%, 10% and 8% MC briquettes
respectively:
NBR = 1.1003e–1.128s
NBR=1.0924e–0.938s
NBR = 1.02775e–0.526s
6
7
8
An exponential function for each curve shows that
the least-squares t line is satisfactory.
To determine the values of B and β for each of the
three normalized burn rates of briquette, the
mean value for the constant β was determined for
each briquette samples as shown in Table 7 which
gives a mean of 0.864±0.002 for the sawdust
briquettes burnt and the normalized burn rate
(NBR) for the briquette expressed as:
NBR = 1.0632e–0.864s
9
Table 7: Values of B and β for briquette moisture
on NBR
B(hr-1)
β
1.1003
1.128
10
1.0624
0.938
8
1.0275
0.526
Mean
1.0632
0.864
MC (%)
12
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Effect of density on NBR: The relative importance
of density on the normalized burn rate is required
to understand the degree to which each factor is
needed to be controlled in briquette manufacture.
The normalized burn rate was determined and a
least-squares t of the normalized mass was
plotted against the density (Figure 5a).
London Journal of Research in Science: Natural and Formal
Figure 4: Plot of phase burning of each briquette and burn rate
Figure 5: Effects of briquette density on a) NBR and b) total burning time (TBT)
The trend in Figure 5(a) indicates that normalized
burn rate increases with an increase in briquette
density. After an exponential fit on the scattered
plot of NBR versus density, values of constants B
and β
were estimated for the curve by regression
analysis as B=0.501 and β
= −0.001 the NBR
equation for the exponential curve is:
NBR = 0.501e–0.001s
10
From the equations, the NBR shows a clear
tendency to decrease as the density increases, as
predicted from literature (Chaney, 2010). The
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
Briquette Stove
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London Journal of Research in Science: Natural and Formal
result shows the significance of density on
normalized burn rate; higher density briquettes
have a lower normalized burn rate.
Effect of density on briquette total burning time:
Considering the total time taken to burn the whole
briquette starting from the initial mass to the
maximum mass loss (approximately 5% of initial
mass (Mandal et al., 2012) to determine the total
burning time (TBT), a plot of time against density
(Figure 5b) gives a good estimation of (TBT). An
exponential regression analysis provided the best
fit curve with the regression equation (11)
predicting the total burning time at a given
density:
TBT = 0.002e–0.008s
11
The result indicates that high briquette density
was responsible for slow flame propagation
resulting in longer burning time. By implication,
the higher density briquette takes more time to
burn out while a lower density briquettes took
shorter time but reach burning phase 2 faster than
higher density briquettes.
Effect of briquette density on burn rate: It is
equally significantly important to note that the
density of briquette increases as the mass to
volume ratio reduces. The impact of mass-volume
reduction on density is graphically illustrated for
briquette samples in Figure 6 and these show
some inverse relationships between reduced mass
and density of all test samples with significant
correlations in lower moisture briquettes:
(0.0413, 0.969 and 0.948) for 12%, 10%, and 8%
briquettes respectively.
Briquette burn rate in boiling water (WBT) and
control cooking tests (CCT): From Table 4, it
takes a shorter time (0.07hrs), to boil 1.50kg of
water with 8% moisture content briquette, and
consuming 1.05kg of fuel, while it takes longer
time (0.9<0.78<0.07) hrs to consume the
relatively same quantity of fuel for other
briquettes.
Figure 6: Effect of burn rate on mass reduction and density of 12%, 10% and 8% briquette
Combustion Characteristics of High-Density Briquettes Produced from Sawdust Admixture and its performance in
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Stove performance evaluation: from the results,
the stove has different thermal efficiencies and
specific fuel consumption (SFC) when tested with
different briquette samples. The result of the
thermal efficiency and the average specific fuel
consumption of the stove obtained from the
experiment are (64.38%, 52.64% and 34.56%),
and (0.6, 0.68, 0.75) kg/hr. for 12%, 10% and 8%
briquette samples respectively. The thermal
efficiency of the stove increases with an increase
in briquette material moisture content while the
specific fuel consumption increases with a
decrease in moisture content. This result implies
that stove performance characteristics are largely
dependent on fuel material quality. Equally, from
the result, it is evident that the fuel burn rate has
a significant effect on the stove’s thermal
performances. The ability to control fuel burn rate
is therefore essential if thermal stove
performances are to be optimized and that there is
an optimum fuel burn rate that could give
maximum stove efficiency for a given
configuration (Kandpal et al., 1994).
IIIV.
CONCLUSION
Form the experimental considerations; the
briquette burn characteristics improves with
increase in briquette quality. Burn rate increased
for briquettes produced at lower moisture
content, and reduced for higher density
briquettes. Briquette combustion characteristics
are dependent on the environmental conditions
under which it is burned and also on the medium
in which they are burned. Briquette burn rates
vary from open-air burning, to controlled air
(stove) burning. The briquette stove’s thermal
efficiency is dependent on the quality of fuel.
There is an inverse relationship between specific
fuel combustion and thermal efficiency of the
stove. The higher the briquettes particle moisture,
the higher the specific fuel combustion and the
lower the stove thermal efficiency and vice versa.
Conflict of Interests
The authors declared that there is no conflict of
interests regarding the publication of the article..
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