This research was conducted for a cleaner densified biomass solid fuel to reduce the dependency on woodland which is increasingly becoming critical due to rural cooking. In this paper study was conducted to determine the optimum mixing ratio of coal dust (CD) to saw dust (SD) to produce a solid fuel-CSB (Coal Saw Briquette). Mixing inefficiency shows starch and water are also required for adequate strength of CSB. Objective of the study was to investigate PHU, emission analysis and cost factor. From research, it was concluded that CD to SD of ratio 70:30 is suitable for production and usability. Absence of critical particulate emission (like carbon monoxide) and higher calorific value promotes it as an alternative sustainable fuel in rural society. CSB not only reduce the use of wood energy but also decreases the statistic for premature death due to indoor air pollution caused from cooking with biomass.

1. 1
Proceedings of the 23rd National Heat and Mass Transfer Conference and
1st International ISHMT-ASTFE Heat and Mass Transfer Conference
IHMTC2015
17-20 December, 2015, Thiruvananthapuram, India
IHMTC2015-49
PREPARATION OF BRIQUETTE IN AN INNOVATIVE AND COST
EFFECTIVE WAY AND ITS TESTING FOR RURAL HOUSEHOLD APPLICATION IN EASTERN
INDIA
Bibhuti B. Samantaray
School of Mechanical
Engineering, KIIT University
Bhubaneswar, Odisha, 751024, India
bbsr.comofficial@gmail.com
Chinmay K. Mohanta
Department of Mechanical
Engineering, Gandhi Engineering
College, Bhubaneswar, Odisha, India
Chinmaymohanta551@gmail.com
ABSTRACT
This research was conducted for a cleaner
densified biomass solid fuel to reduce the dependency on
woodland which is increasingly becoming critical due to
rural cooking. In this paper study was conducted to
determine the optimum mixing ratio of coal dust (CD) to
saw dust (SD) to produce a solid fuel-CSB (Coal Saw
Briquette). Mixing inefficiency shows starch and water are
also required for adequate strength of CSB. Objective of
the study was to investigate PHU, emission analysis and
cost factor. From research, it was concluded that CD to SD
of ratio 70:30 is suitable for production and usability.
Absence of critical particulate emission (like carbon
monoxide) and higher calorific value promotes it as an
alternative sustainable fuel in rural society. CSB not only
reduce the use of wood energy but also decreases the
statistic for premature death due to indoor air pollution
caused from cooking with biomass.
Keywords: Briquette, Innovative, Rural household, Cost
effective
INTRODUCTION
In India 2.5 billion i.e. 52% of population residing
in rural belt rely every day for cooking on biomass as their
primary fuel i.e. fuelwood, charcoal, agri waste, animal
dung. In absence of norms and policies number of people
attributing for biomass increases to over 2.6 billion by
2015 and over 2.7 billion by 2030 due to vigorous and
concerted population growth [1]. Massive use of biomass is
not itself a cause of concern but when resources are
harvested unsustainably along with inefficient energy
conversion technologies it impairs health and has negative
economic and environmental impacts.
Biomass, roots, charcoal produce high emission of
carbon monoxide, hydrocarbon and particulate matter
which results in the death of 1.3 million People
prematurely every year because of exposure to indoor air
pollution. It is estimated that indoor air pollution causes
36% of lower respiratory infection and 22 % of chronic
respiratory diseases. There is evidence which link indoor
smoke to low birth weight, infant mortality, tuberculosis,
cataracts, asthma. Indoor air pollution have direct effects
on health as it worsen the suffering and shorten the lives
hence increases the statistics of premature death due to the
use of biomass for cooking. Yue Wang et al. [2]
At present wood and coal are combusted directly
without optimization of energy efficiency nor control of
particulate emission. Bhattacharya et al [3] and Tumuluru
et al. [4] studied numerous strategies to convert various
types of biomass into fuel having better characteristics.
Among these one is biomass densification i.e. the
compaction of raw fuel into a briquette of up to 10 time’s
higher density than parent one.
Such processing of densification leads to the
reduction of particulate emission per unit volume and
storage requirement by the increase in bulk and energy per
unit volume. The blend of coal dust with wood saw

2. 2
particles will result in the formation of a solid fuel
briquette with a lower ash content which is a strong
direction towards improvised utilization of coal and wood
in future development. To improve briquette characteristics
starch, a polysaccharide i.e. maize flour is mixed with
water which not only has a high energy content but also is
the best binding agent due to its structural and chemical
properties. Satin et al [5] studied about this in his study.
Swelling develops between the components of starch
granules with the gradual addition of water to the mixture.
Tako et al [6] mentioned in his study that the amylose and
amylopectin component shred their individual crystalline
structure which forms a viscous solution to increase the
shear and tensile strength of briquette. This viscosity
allows the solution to occupy the void spaces present
within and between particles in briquette.
Pressure plays a major role as it gives the shape as
well as close the void spaces promoting plastic and elastic
deformation. Cross ward and statistical analysis such as
time-temperature study, PHU, thermal efficiency of the
stove and emission tests are done. Being affordable and
less pollutant, it has got its high rise demand in nearby
future.
EXPERIMENTATION
Sourcing and Preparation of Raw Materials
Two bulk samples of dried saw powder (from
carpentry shops and sawmills) and coal dust (from coal
mines or waste coal dump yards) were sourced and
collected. Maize Starch which is a polysaccharide is widely
available, act as a binder in briquetting. The grindability of
the coal is the measure of its burning. More is the crushed,
fine and pulverized particles more effective is the
combustion. Studies shows that if nearly 80% of coal load
passed through a 30 mesh sieve of screen opening 74
micrometers or 0.003 inch, then the coal is suitable for
preparation Britannica 2015 [7]. On gradual stages, saw
dust is taken and fermented in water for nearly 4 days so as
to carbonize properly. After carbonization it would produce
less amount of smoke as compared to its parent stage.
Characterization of the briquette include determination of
bulk density by BS EN 15103 [8], moisture content by BS
EN 14774-2 [9], and water absorption by BS EN 772-21
[10]. Fine maize starch powder was converted into the
binder paste by mixing with water at a mass ratio of 1.5: 3.
Table 1: COMPOSITION OF MATERIAL ANALYSIS
OF FEED COAL
Material Dried percentage of
composition
1. Ash 19.21
2. Volatile matter 10.93
3. Fixed carbon 69.86
Table 2: COMPOSITION OF CHEMICAL ANALYSIS
OF FEED COAL
Material Percentage of composition
1. Carbon 89.37
2. Hydrogen 4.58
3. Nitrogen 3.97
4. Sulphur 1.63
5. Oxygen 0.45
Table 3: COMPOSITION OF MATERIAL ANALYSIS OF
SAW DUST
Material Percentage of composition
1. Volatile matter 67.43
2. Carbon 19.71
3. Calorific value 3425
4. Sulphur 0.56
5. Moisture 6.74
Table 4: COMPOSITION OF CHEMICAL ANALYSIS
OF SAW DUST
Material Dried percentage of
composition
1. Carbon 47.2
2. Hydrogen 6.5
3. Nitrogen 0.3
4. Sulphur 0.3
5. Oxygen 44.9
Table 1 shows the material analysis of the composition
present in the feed coal. This allows us to get a rough idea
on its composition. Table 2 shows the chemical analysis of
the feed coal which helps us to analyze the emission result.
Similarly table 3 shows the material analysis of the
composition in saw dust. Table 4 shows the chemical
analysis of the saw dust.
Experimental Design and Setup
A schematic graphical interface of the whole
experimental set up is shown in the Fig.1. The
experimental setup is a very simple yet sophisticated with
the use of a rural stove “CHULLAH” fitted with a blower,
4 k-type thermocouples, a data acquisition system, a hot
wire anemometer, a computer and a flue gas analyzer. All
the experiment are conducted in the controlled condition
with closed environment and at normal room temperature.
The traditional stove or CHULLAH is a normal cooking
stove generally used in rural India. The CSB is designed
and manufactured by keeping in mind the configuration of
the CHULLAH.

3. 3
FIGURE 1. SCHEMATIC DIAGRAM OF THE
EXPERIMENTAL SETUP
The main function of air blower is to supply required
amount of air to the combustion chamber as we know the
air plays a very vital role in the combustion so we have
conducted the test at three different air flow velocity i.e. 0
m/s, 1.5 m/s and 3m/s. The air flow was measured by the
hot wire anemometer. The k-type thermocouples are
arranged in horizontal and vertical manner to record the
time dependent temperature data. Out of 4 thermocouple
two are arranged in vertically as Thermocouple-1 and
Thermocouple-2 similarly other two Thermocouples-3 and
Thermocouples-4 are arranged horizontally.
Thermocouple-1 is 35mm away from the surface of the
stove while thermocouples-2 is 70 mm away from the
surface of the stove. Similarly Thermocouple-3 positioned
in the middle point of the radius of the stove while the
Thermocouple-4 is positioned just in the periphery of the
flame. All the four thermocouples are connected to the data
acquisition system, which is connected to a computer for
live data analysis. Also an IR camera is used to take the
static thermal images for further analysis if necessary.
Briquette Production
The pulverized coal from hammer crusher and
sieved saw dust were collected and mixed up in a limited
air vessel. The times required to carbonize both raw
material are 2 and 4 days respectively. Maize starch of 15%
wt. was added as binder. Slight amount of lime stone or
calcium carbonate is added with the mixture for better and
progressive combustion so that it could yield white ash as
residue.
Hydrated lime or sorbent is added in 2-3% to
convert the Sulphur gas to solid ash formed during
combustion. All the feed materials were stirred for 15 mins.
After these components were fully mixed, water was
introduced to give a moisture content up to 12% to the
briquettes. Molten liquid bituminous III is added at the last
process so to provide the initial ignition temperature. Slight
amount of borax powder is used to diminish the sticking
property during pressing or molding of mixture. The
briquette mixture is then densified using a hand held steel
mold with an inner diameter 30mm, length 100mm, outer
diameter 50mm. Based on research by some authors , a
hold time f 40 sec for compression with 30 MPa pressure
has a little effect on briquette C.O. Chin et al. [11],
M.L.Al-widyan et.al[12]. Hence in this case 30 MPa with
60 sec hold time is done to get the desired compaction and
then extruded from the hole shown on right side. All
produced samples are cured for 24 hr at 23±2 ˚C and
relative humidity of 45±5 % before testing so as to get the
unconfined optimum result.
Table 5: Composition of Sample
Coal
(in gm)
Saw
Dust
(in gm)
Maida
(in
gm)
Lime
powder
(in gm)
Total
Weight
(in gm)
Sample 19.88 9.99 3 1.5 35
Procedure for PHU testing
The percent heat utilization test, otherwise called
as PHU test is used to find thermal efficiency of the stove.
Generally, PHU is a ratio of the useful heat (i.e. the heat
delivered to the cooking utensil from stove) to the total
heat content of the fuel supplied. PHU is calculated as
follows
PHU = [Heat gained by water in the pans (x)/Heat supplied
by the combustion of fuel (v)]* 100
Where, x = [(quantity of water used) * (rise in temperature)
* (specific heat of water)] + [(weight of evaporated water)
* (latent heat of water)]
And y = (weight of fuel used) * (calorific value).
The PHU test was done for the given fuel device
combination. The procedure followed is similar to the
VITA protocol; details are given in an earlier study by
Lokras et al., [13]. PHU is a good measure of the thermal
efficiency of stoves though it may not reflect the results of
actual cooking procedures that do not involve boiling or
where the heat supply varies.
FIGURE 2. REAL IMAGE OF PRODUCED
BRIQUETTE

4. 4
34
37
50.4
0
10
20
30
40
50
60
Kerosene Wood CSB
Thermal Efficiency, %
Different Fuels
0.45 0.59 0.67
17
34
47
0
5
10
15
20
25
30
35
40
45
50
0 1.5 3
NOX, CO EMISSION, PPM, %
AIR FLOW RATE, M/S
CO NOx
Procedure for Emission Test:
The experimental setup is designed in such a way
that it can be closed after the combustion initiates. For
emission test whole experiment is being conducted as such.
The briquette is burnt inside a closed chamber with a small
exhaust outlet. The probe of the flue gas analyser is
inserted in the exhaust outlet of the hood. The flue gas
analyser shows the different emission value automatically
such as hydrocarbon and carbon monoxide percentage. The
flue gas analyser is AVL DIATEST-DIAGAS 444 model
used for testing various particulate emission.
FIGURE 4: IMAGE OF BRIQUETTE-COMBUSTION
DURING EMISSION TEST
RESULT AND DISCUSSION
The use of direct wood and coal has serious
adverse consequences on health. Generally women and
children are more prone to premature death as they used to
spend more hours for indoor cooking. But In CSB the
amount of particulate emission decreased to a high extent
due to the carbonization and mixing of starch granules.
Hydrated lime, available in market as thin sheets, are added
to capture the Sulphur gas and convert them into solid ash.
Carbonization decreased the production of hydrocarbon as
well as black smoke during initial combustion.
PHU Result
The PHU was calculated as mentioned in the working
procedure. The PHU of the taken sample was found to be
around 45%. Though it is not in the higher side but it is
still encouraging as it is being produced totally form the
waste. Also it was observed that the PHU result was better
in the summer time and can even go up to 46-47% on some
certain conditions while it was on the lesser side in the
winter conditions. It was also noted that varying the
process parameters the PHU value fluctuates in the same
range of 44-45%.
Emission result
The emission test was conducted while
conducting the thermal efficiency test in a confined
environment with three different air flow rate i.e. 0 m/s, 1.5
m/s, 3 m/s. So the values of CO and NOx also varied along
with the change of the flow rate. The value of CO was in
the range 0.45-0.67 % while the values of the NOx was in
the range of 17-47 ppm (Fig.5). The emission values of CO
and NOx was well within the range of the other
Conventional fuel used for rural cooking. Here in the air
flow rate of 1.5 m/s we also obtained the average emission
value which shows a good agreement as that is the desired
air flow rate.
FIGURE 5: COMPARISON OF THERMAL
EFFICIENCY WITH OTHER RURAL COOKING FUEL
FIGURE 6: AIR FLOW RATE-EMISSION GRAPH
Cost analysis
Cost of briquette plays a relevant role in the usage
of briquette as the rural households earn to eat. If the price

5. 5
6
9
11
5.5
9.5 9
13
7
0
5
10
15
COST IN RS PER KWH
FUELS USED IN RURAL SECTOR
Effective cost of
household fuels
of fuel should be relevant enough for them then the
demand will increase result a path towards a green and
cleaner future. With the combination of coal and saw dust,
the briquette formed needs a cost of Rs 5 per KWh. This is
the most cheaply available fuel with minimum emission of
particulate matter from it.
Future scope
Now a days fossil fuels have become very
FIGURE 7: COMPARISON OF BRIQUETTE COST
expensive and spread lot of pollution. They are not counted
as a cleaner sustainable source of energy. Hence
briquetting technology is being followed all over the world.
Briquetting is rapidly growing due to its biodegradable,
less emission and economical feature. Now a days more
preference is given to Eco friendly and cheaper fuels which
is the CSB. If CSB is taken into serious account then the
day is not far when rural as well as urban fellow will grant
CSB as their primary fuel for cooking. This will move
India towards a new era of future development.
Conclusion
This study has demonstrated that high efficiency
and low particulate emission briquette of consistent quality
can be produced from the blend of coal dust with saw
powder along with required raw materials. The source of
feed materials did not affect the briquette strength but have
positive effect on densification and green density. Higher
compaction pressure resulted in formation of briquette with
less void space and remain compacted and durable. So by
using CSB for cooking it can save the deforestation to
some extent while utilizing the coal dust which has
practically no notable use except air pollution. The
economics of the CSB is also on the very lower side so it
will not affect the people who want to make it as their
primary fuel for cooking.
REFERENCES
[1] “ENERGY FOR COOKING IN DEVELOPING
COUNTRIES”,2006 OECD/IEA, see also
https://www.iea.org/publications/freepublication/publ
ication/cooking.pdf
[2] Yue Wang and Xiangfei Bai, 2015, “Optical
microscopy analysis of briquette binders”, Int J Coal
Sci Technol DOI 10.1007/s40789-015-0051-8
[3] S.C.Bhattacharya, L.M.Augustus and R.M.Mizanur,
1996, “A study on improved biomass briquetting”,
energy program, school of environment, resources and
development Asian institute of technology, pp 1-2.
[4] J.S.Tumuluru, C.T.Wright, J.R. Hess and K.J, Kenney,
2011, “A Review of biomass densification systems to
develop uniform feedstock commodities for bio energy
application”, biofuels,bioproducts and biorefining (5)
pp 683-707.
[5] M.Satin , 1998, “Functional Properties Of Starches” ,
Agricultural and food engineering technologies
services, food and Agricultural organization (FAO).
[6] M.Tako and S.Hizukuri , 2002, Gelatinization
mechanism of Potato starch ,Carbohydrate polymers
(48),pp 397-401.
[7] Morley RJ , 2015, “Coal utilization”. Encyclopedia
Britannica. See also
http://www.britannica.com/EBchecked/topic/122944/c
oal-utilization
[8] BS EN 15103, 2009, “Solid Biofuels – Determination
of bulk density”.
[9] BS EN 14774-2, 2009, “Solid fuels – determination of
moisture content, part 2: Total Moisture – simplified
method”.
[10] BS EN 772-21, 2011, “Methods of test for masonry
units part 21: Determination of water absorption of
clay and calcium silicate masonry units by cold water
absorption”.
[11] C.O.Chin and K.M.Siddiqui,2000, “Characteristics of
some briquettes prepared under modest die pressures”,
Biomass and Bioenergy (18) pp 223-228.
[12] M.I. Al-Widyan, H.F.Al-Jilal, M.M.Alxi –Zreig and
N.H.Abu-Hamdeh, 2002, “physical durability and
stability of olive cake briquettes”, Canadian Biosystem
Engineering (44), pp 341-345.
[13]Lokras, S. S., Babu, S. S., Bhogle. S., Jagadish, K. S.
and Kumar R, 1983, “Development of a three pan
cookstove” Changing Villages 5 (5).