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List of Tables
Table no. Description Page no.
1 Availability of agricultural waste in India……………………… 6
2 Ash content of few types of biomass……………………………. 12
3 Traditional Energy Used in developing countries……………. 15
4 Consumption of biomass in selected Asian countries………….. 16
5 Estimated biomass saving potential…………………………...... 16
6 Parts of machine……………………………………………….. 28
1
List of FiguresFigure Title Page no.
1 screw press system…………………………………… 16
2 Piston press system……………………………………17
3 Crushing system……………………………………….29
4 Mixing system…………………………………………30
5 Extrusion system……………………………………....30
6 Complete assembly of briquetting machine…………... 33
2
ABBREVIATIONS
KMTNC King Mahindra Trust For Nature Conservation
CO2 Carbon Dioxide
NOX Nitrogen Oxide Compounds
SO2 Silicon Dioxide
EKCC Eastern Kentucky Coal Consultants
CDM Clean Development Mechanism
GHG Green House Gas
BETs Briquetting Energy Technologies
MPa Mega Pascal
t/h Tones per Hour
IREDA Indian Renewable Energy Development Agency
MNEs Ministry of Non-Conventional Energy Resource
USAID United States Agency for International Development
HP Horse Power
MT Metric tonne
3
NOMENCLATURE
Symbols Stand for
σ Tensile stress in N/m2
ρ Density in kg/mm3
V Velocity in m/sec
B Width of belt
t Thickness of pulley
P Power
N r.p.m
T Torque in Nm
WT Tangential load per arm
D Diameter of pulley
M Maximum bending moment
d1 Hub diameter
4
CHAPTER-1
INTRODUCTION
1.1 PROJECT BACKGROUND:-
Agriculture has for several years formed the backbone of India’s economy, contributing
approximating 30.2% of the gross domestic product employing over 77% of the
population above 10 years of age. Developing countries like India produce large
quantities of agro-residues such as rice husks, coffee husks, bagasse, groundnut shells,
cotton stalks, cow dung and sawdust as milling residue is also available in large
quantities, but they are used inefficiently causing extensive degradation to the
environment. Briquetting could solve this transportation, storage, handling and
environmental degradation problems associated with agro residues.
Briquetting is a mechanical compaction process for increasing the density of bulky
material. Briquettes are a good substitute to firewood and charcoal for domestic cooking
and agro-industrial operations, thereby reducing the high demand for both. Besides,
briquettes have advantages over fuel wood in terms of greater heat intensity, cleanliness,
convenience in use, and relatively smaller space requirement for storage. However,
Briquetting agro-residues need a Briquetting machine. The existing machines are scarcely
available to rural people, use electricity and the cost of fuel is high, bulky and expensive.
They need skilled man power to operate and maintain them.
Many people in India still adopt the traditional method of Briquetting using hands. This
method of Briquetting is associated with a number of problems; Time consuming,
Tedious, Accuracy is compromised, requires a great deal of skill and effort to briquette,
low production and wastage. This project seeks to come up with a fast briquetting
technique, which can be employed by those involved in briquette making. Fast
briquetting results into increased output per day to meet the briquette demand plus
minimized amount of hand working.
5
Table 1- Availability of agricultural waste in India
CROP RESIDUE AVAILABILITY
(MT/year)
REMARK
Coffee Fronds, husk, shell 560,000 5% used
commercially
Coconut Hull, husk, ground 100,000 8% used
commercially
Corn Cob, Stover, stalks,
leaves
120,000 2% used
commercially
Cotton Stalks 236,000 70% used
commercially
Nuts Hulls 50,000 12% used
commercially
Peanuts Shells 32,000 5.5% used
commercially
Rice Hull, Straw, stalks 210,215 No commercial use
Agriculture crops Mixed agricultural
crops, not limited to
crop waste
500,000 No commercial use
Mixed type Agricultural crops
and waste including
non-organic wastes
100,000 No commercial use
Sugarcane Bagasse 425,000 20% used
commercially
Animal Dung 515,000 No commercial use
6
1.2 PROBLEM STATEMENT
The available Briquetting machines are expensive, use electricity and require high
technology in terms of operation and maintenance, and yet most of the targeted
population (rural areas) have no electricity and cannot afford the available expensive
machines. The traditional way of making briquettes by hand is labor intensive and the
briquettes made are not uniform, as the pressure exerted on them by hand is not
uniformly distributed. Loose biomass is associated with low energy densities.
Combustion properties limit use of agro-residues as fuel. Deforestation and wood fuel
shortages are becoming pressing problems in India and as such, attention has to be paid to
other types of biomass fuel, which include agro-residues, but for effectiveness the agro
residues have to be compressed thus need for a briquetting machine.
1.3 JUSTIFICATION
If the local population accepts the prototype of the improved briquetting machine, the
benefits below shall be achieved;
a. The amount of briquettes made per unit time or per day shall be increased.
b. Since the machine shall use no fuel, no electricity, then no cost will be incurred
in paying the bills associated with the energy sources mentioned.
c. Less effort will be required to operate it. The machine will be affordable to the
local population, will not require skilled personnel to operate and maintain it, and
will produce uniform briquettes.
1.4 SCOPE
This project will be limited to the design of a briquetting machine. Briquettes mainly
composed of agricultural waste, charcoal dust and cow dung used in both rural and urban
areas. It’s designed to compact and compress the mentioned agro-residues to a cylindrical
briquette of 35mm.
7
CHAPTER-2
LITERATURE REVIEW
2.1 History
Briquetting is a mechanical compaction process for increasing the density of bulky
materials. This process can be utilized for forming fine or granular agro residues into a
designed shape. Briquetting improves the handling characteristics of the materials for
transport, storing etc and can help in expanding the use of biomass in energy production,
since densification improves the volumetric calorific value of a fuel, reduces the cost of
transport and can help in improving the fuel situation in rural areas. Raw materials for
Briquetting include waste from wood industries, loose biomass and other combustible
waste products.
Though inefficient, the burning of loose biomass created enough heat for cooking
purposes and keeping warm. The first commercial production plant was created in 1982
and produced almost 900 metric tons of biomass. In 1984, factories were constructed that
incorporated vast improvements on efficiency and the quality of briquettes. They used a
combination of rice husks and molasses. The King Mahindra Trust for Nature
Conservation (KMTNC)
In 1925, Japan independently started developing technology to harness the energy from
sawdust briquettes, known as "Ogalite". Between 1964 and 1969, Japan increased
production fourfold by incorporating screw press and piston press technology. The
member enterprise of 830 or more existed in the 1960's. The new compaction techniques
incorporated in these machines made briquettes of higher quality than those in Europe.
As a result, European countries bought the licensing agreements and now manufacture
Japanese designed machines.
2.2 Present Status
The use of biomass briquettes has been steadily increasing as industries realize the
benefits of decreasing pollution through the use of biomass briquettes. Briquettes provide
8
higher calorific value per dollar than coal when used for firing industrial boilers. Along
with higher calorific value, biomass briquettes on average saved 30–40% of boiler fuel
cost. But other sources suggest that cofiring is more expensive due to the widespread
availability of coal and its low cost. However, in the long run, briquettes can only limit
the use of coal to a small extent, but it is increasingly being pursued by industries and
factories all over the world. Both raw materials can be produced or mined domestically in
the United States, creating a fuel source that is free from foreign dependence and less
polluting than raw fossil fuel incineration.
Environmentally, the use of biomass briquettes produces much fewer greenhouse gases,
specifically, 13.8% to 41.7% CO2 and NOX. There was also a reduction from 11.1% to
38.5% in SO2 emissions when compared to coal from three different leading producers,
EKCC Coal, Decanter Coal, and Alden Coal. Biomass briquettes are also fairly resistant
to water degradation, an improvement over the difficulties encountered with the burning
of wet coal. However, the briquettes are best used only as a supplement to coal. The use
of cofiring creates an energy that is not as high as pure coal, but emits fewer pollutants
and cuts down on the release of previously sequestered carbon. The continuous release of
carbon and other greenhouse gasses into the atmosphere leads to an increase in global
temperatures. The use of cofiring does not stop this process but decreases the relative
emissions of coal power plants.
The Legacy Foundation has developed a set of techniques to produce biomass briquettes
through artisanal production in rural villages that can be used for heating and cooking.
These techniques were recently pioneered by Virunga National Park in
eastern Democratic Republic of Congo, following the massive destruction of
the Mountain Gorilla habitat for charcoal.
Pangani, Tanzania, is an area covered in coconut groves. After harvesting the meat of the
coconut, the indigenous people would litter the ground with the husks, believing them to
be useless. The husks later became a profit center after it was discovered that coconut
husks are well suited to be the main ingredient in bio briquettes. This alternative fuel
mixture burns incredibly efficiently and leaves little residue, making it a reliable source
for cooking in the undeveloped country. The developing world has always relied on the
burning biomass due it its low cost and availability anywhere there is organic material. 9
The briquette production only improves upon the ancient practice by increasing the
efficiency of pyrolysis.
Two major components of the developing world are China and India. The economies are
rapidly increasing due to cheap ways of harnessing electricity and emitting large amounts
of carbon dioxide. The Kyoto Protocol attempted to regulate the emissions of the three
different worlds, but there were disagreements as to which country should be penalized
for emissions based on its previous and future emissions. The United States has been the
largest emitter but China has recently become the largest per capita. The United States
had emitted a rigorous amount of carbon dioxide during its development and the
developing nations argue that they should not be forced to meet the requirements. At the
lower end, the undeveloped nations believe that they have little responsibility for what
has been done to the carbon dioxide levels. The major use of biomass briquettes in India
is in industrial applications usually to produce steam. A lot of conversions of boilers from
FO to biomass briquettes have happened over the past decade. A vast majority of those
projects are registered under CDM (Kyoto Protocol), which allows for users to get carbon
credits.
The use of biomass briquettes is strongly encouraged by issuing carbon credits. One
carbon credit is equal to one free ton of carbon dioxide to be emitted into the atmosphere.
India has started to replace charcoal with biomass briquettes in regards to boiler fuel,
especially in the southern parts of the country because the biomass briquettes can be
created domestically, depending on the availability of land. Therefore, constantly rising
fuel prices will be less influential in an economy if sources of fuel can be easily produced
domestically.
Coal is the largest carbon dioxide emitter per unit area when it comes to electricity
generation. It is also the most common ingredient in charcoal. There has been a recent
push to replace the burning of fossil fuels with biomass. The replacement of this
nonrenewable resource with biological waste would lower the carbon footprint of grill
owners and lower the overall pollution of the world. Citizens are also starting to
manufacture briquettes at home. The first machines would create briquettes for
homeowners out of compressed sawdust, however, current machines allow for briquette
production out of any sort of dried biomass. 10
Arizona has also taken initiative to turn waste biomass into a source of energy. Waste
cotton and pecan material used to provide a nesting ground for bugs that would destroy
the new crops in the spring. To stop this problem farmer buried the biomass, which
quickly led to soil degradation. These materials were discovered to be a very efficient
source of energy and took care of issues that had plagued farms.
The United States Department of Energy has financed several projects to test the viability
of biomass briquettes on a national scale. The scope of the projects is to increase the
efficiency of gasifies as well as produce plans for production facilities.
Biomass is composed of organic materials; therefore, large amounts of land are required
to produce the fuel. Critics argue that the use of this land should be utilized for food
distribution rather than crop degradation. Also, climate changes may cause a harsh
season, where the material extracted will need to be swapped for food rather than energy.
The assumption is that the production of biomass decreases the food supply, causing an
increase in world hunger by extracting the organic materials such as corn and soybeans
for fuel rather than food.
The cost of implementing a new technology such as biomass into the current
infrastructure is also high. The fixed costs with the production of biomass briquettes are
high due to the new undeveloped technologies that revolve around the extraction,
production and storage of the biomass. Technologies regarding extraction of oil and coal
have been developing for decades, becoming more efficient with each year. A new
undeveloped technology regarding fuel utilization that has no infrastructure built around
makes it nearly impossible to compete in the current market.
M.B Oumarou and Oluwole F.A [1] has presented the design and construction of a
suitable machine that can compress wood waste and agricultural waste materials into
briquette which can be used as fuel would therefore be a solution to the problem of
environmental resources conservation. Generally briquette processing machine are
relatively large, heavy and costly. What needed is a small, light, simple and cheap
press which can be constructed with local materials available locally. Considering the
fact that a manual operated press required the person, who pulls or pushes down the level
11
to exert a great force up to about twice every minute it became clear that gradual
exhaustion causes diminishing performance.
There is also a tendency to produce briquettes of irregular size or compaction, depending
on compressing system. If filling the mould is done manually, apart from producing
irregular sizes and low rate of production per machine it will require a number of
machines to achieve an output. Biomass residues normally have much lower ash content
(except for rice husk with 20% ash) but their ashes have a higher percentage of
alkaline minerals, reasonable especially potash. These constituents have a tendency
to devolatalise during combustion and condense on tubes, especially those of super
heaters. These constituents also lower the sintering temperature of ash, leading to
ash deposition on the boiler’s exposed surfaces.
Table2: Ash content of few types of biomass.
Biomass Ash content (%) Biomass Ash content (%)
Corn cub 1.2 Coffee husk 4.3
Jute stick 1.2 Cotton shells 4.6
Sawdust (mixed) 1.3 Tannin waste 4.8
Pine needle 1.5 Almond shell 4.8
Soya bean stalk 1.8 Areca nut shell 5.1
Bagasse 1.8 Castor stick 5.4
Coffee spent 1.9 Groundnut shell 6.0
Coconut shell 1.9 Coir pith 6.0
Sunflower stalk 3.1 Bagasse pith 8.0
Jowar straw 3.2 Bean straw 10.2
Olive pits 3.2 Barley straw 10.3
Arhar stalk 3.4 Paddy stalk 15.5
Lantana camara 3.5 Tobacco dust 19.1
Subabul leaves 3.6 Jute dust 19.1
Tea waste 3.8 Rice husk 22.4
Tamarind husk 4.2 Deoiled bran 28.4
12
S.C Bhattacharya [2] has presented that Global primary commercial energy consumption
has grown at an average annual rate of about 2% per year over the last two hundred
years; during 1990-2000, the consumption increased by 11%. Currently, conventional
commercial energy sources - coal, oil, natural gas, nuclear and hydropower - account for
85-90% of global primary energy consumption; fossil fuels account for approximately
ninety per cent of the conventional commercial energy consumption. Since developing
countries are at initial stages of industrialization, their energy consumption has been
growing at greater rates compared with developed countries. Thus, during 1990-2000,
conventional energy consumption of the developing countries of the Asia Pacific region
increased by 27 per cent compared with 11 per cent growth of the world consumption.
The trend of growth in global energy consumption is expected to continue in the future -
primarily because of the expected growth in world population and the expected economic
growth of the developing countries. It is likely that the current pattern of energy
consumption, which is characterized by continued growth and heavy dependence on
fossil fuels, cannot be sustained in the future because of two major constraints. One of
these is the environmental impact of using fossil fuels, particularly climate change and
the other is the depletion of the reserves of fossil fuels. Since the biggest source of
greenhouse gas (GHG) emission is the combustion of fossil fuels, one of the most
effective approaches to the mitigation of GHG emission would be reducing consumption
of these fuels through their substitution by renewable energy. The same approach is also
vital for reducing the rate of depletion of fossil fuels, particularly oil, the proved reserve
of which at the end of 2000 was about 40 years of consumption at the prevailing level.
Biomass is the fourth largest source of energy worldwide and provides basic energy
requirements for cooking and heating of rural households in developing countries. Use of
biomass fuels is also well established in certain commercial establishments and
industries. In developed countries, biomass energy use in developed countries is mainly
for space heating and power generation. The biomass fuels could potentially provide a
much more extensive energy service than at present if these were used efficiently.
Besides efficiency improvements of existing energy systems, putting huge quantities of
biomass, mostly in the form of agricultural residues and wastes, which are currently
disposed by burning or dumping, could potentially increase the energy supply from
13
biomass substantially. Significant additional increase in biomass energy supplies should
be possible through energy plantation. Utilization of biomass residues and wastes is often
difficult due to their uneven and troublesome characteristics. This drawback can be
overcome by means of densification, i.e. compaction of the residues into products of high
density and regular shape. Densification has aroused a great deal of interest worldwide in
recent years as a technique of beneficiation of residues for utilization as energy source.
A number of modern BETs are still in early stages of development and
commercialization. Most of these face a wide range of barriers, which must be removed
for promoting and facilitating their commercialization. The prevailing low price of oil in
the international market has seriously eroded the financial viability of many RE systems.
In fact, this has already adversely affected many on-going renewable energy programs,
resulting in significant scaling down in some cases, for example, the ethanol program in
Brazil. The situation is further aggravated by subsidy given to fossil fuels in many
countries. It has been pointed out those worldwide government subsidies for conventional
energy was US$ 250-300 billion per year in the mid-1990s (de Moor and Calamai, 1997).
In India, the Government spent about US$ 1.5 billion annually for subsidizing kerosene
in the late 1990s (Forsyth, 1998). Subsidy for fossil fuels distorts market in favour of
these fuels; for example, this gives diesel generators an unfair advantage over gasifier
engine systems.
The major barriers to biomass energy in developing countries appear to include:
1. Information - since there is a lack of understanding of using biomass for energy in
many countries;
2. Risk - mainly those associated with unproven fuel supply and conversion
technologies;
3. Financial - since the cost of energy from biomass is normally higher compared
with fossil fuels;
4. Market characteristics -mainly arising out the network involving farming/forestry
communities and power producers; and
5. Insufficient policy support for energy crops.
14
The pace of commercialization of biomass energy technologies and future use of biomass
energy will depend on action taken to remove the barriers as mentioned above. In
developing countries, future biomass energy use is likely to be characterized by
improvements in efficiency and environmental performance of traditional energy devices.
Some of the traditional biomass energy users are likely to switch over to commercial
energy, particularly for cooking. On the other hand, climate change and other
environmental concerns and related developments are expected to promote utilization of
cheap biomass, particularly wood- and agro-processing residues. Further utilization of
these as well as plantation biomass is likely as the climate change debate intensifies
and/or the prices of fossil fuels show signs of escalation.
Table 3: Traditional Energy Used in developing countries
Country Traditional fuel
(% of total energy use)
Estimated increase in
traditional energy
consumption between
(In %)
1980 1998
Brazil 35.5 28.7 15.0
China 8.4 5.7 14.6
India 31.5 20.7 11.3
Malaysia 15.7 5.5 11.6
Nicaragua 49.2 42.2 27.6
Peru 15.2 24.6 124.0
Philippines 37 26.9 13.2
Sri Lanka 53.5 46.5 21.6
Sudan 86.9 75.1 19.4
Tanzania 92.0 91.4 31.8
Source of data: World Bank (2002)
Table 4: Consumption of biomass in selected Asian countries 15
(Bhattacharya and Salam,2002 )
Country Base year Domestic sector Industrial and
commercial sector
Amount
(Mt)
Percentage
%
Amount
(Mt)
Percentage
%
China 1993 458.0 94 29.4 6
India 1991 231.5 78 65.9 22
Nepal 1993 15.1 98 0.3 2
Pakistan 1991 48.5 78 14 22
Philippines 1995 18.6 70 8.1 30
Sri Lanka 1993 10.0 87 1.5 13
Vietnam 1991 29.1 91 2.9 9
Table5: Estimated biomass saving potential (Million tonnes year) through efficiency
improvements in the selected countries (Bhattacharya, 1999).
Country Base year Type of biomass
Fuel wood Agri-
residues
Animal
dung
Charcoal
China 1993 51.6 77.2 2.9 -
India 1991 69.5 20.8 32.3 0.5
Nepal 1993 3.1 1.2 0.8 -
Pakistan 1991 17.5 7.3 8.3 -
Philippines 1995 7.6 2.3 - 0.3
Sri Lanka 1993 2.6 0.5 - -
Vietnam 1991 15.8 3.9 - 0.1
Total 167.7 113.2 44.3 0.9
CHAPTER 3
16
THEORY
3.1 DIE PRESSURE RANGES OF BRIQUETTING MACHINES
There are three die pressure ranges of briquetting machines namely;
a) The high-pressure machine where the pressure reaches values more than 100
MPa. This type is suitable for the residues of good lignin content. At this high pressure
the temperature rises to about 200- 250°C, which is sufficient to fuse the lignin content of
the residue, which acts as a binder and so, no need of any additional binding material.
b) The medium pressure machine, with a pressure ranges between 5 MPa to 100
MPa, which results in lower heat generation. This type of machines requires in most of
the cases the use of an additional heat source to melt the internal lignin content of the
feedstock and eliminate the use of an additional binder.
c) The low-pressure machine that work at pressure less than 5 MPa and room
temperature. This type of machines requires the addition of binding materials, and is
considered to be the most suitable type for the carbonized materials due to the lack of the
lignin material due to the carbonization process and the low energy requirement for this
type of machines.
3.2 BRIQUETTING TECHNOLOGIES
There are two common types of Briquetting presses (technologies) employed in
developing countries screw press and piston press technologies.
a) SCREW PRESS TECHNOLOGY
In the screw-presses, pressure is applied continuously by passing the material through a
screw with diminishing volume. There are cylindrical screws with or without external
heating of the die and conical screws. However, if the die is not heated then temperatures
may not rise sufficiently to cause lignin flow and a binding material may have to be
added. This can be molasses, starch or some other cheap organic material. It is also 17
possible to briquette carbonized material in a screw-press and in this, as lignin have been
destroyed; a binder has to be employed. Some low-pressure piston machines may also
require the use of binders though this is unusual. If the die is heated then the temperature
is normally raised to 250-300 °C, which produces a good quality briquette from virtually
all organic feeds provided the initial moisture is below about 15%. The briquettes from
screw machines are often of higher quality than from piston units being harder and less
likely to break along natural fracture lines. Screw presses are usually sized in the range
75-250 kg/in though larger machines are available. The capital costs of screw machines
may be a little less than piston units though because of size differences it is difficult to
make direct comparisons. However, their maintenance costs are usually much higher
because of the considerable wear on the screws, which have to be re-built rather
frequently. They also have a higher specific energy demand than piston machines.
Fig.1: Screw press system
The merits and demerits of this technology are:
a. The output is continuous and the briquette is uniform in size.
b. The outer surface of the briquette is partially carbonized facilitating easy
ignition and combustion. This also protects the briquettes from ambient moisture.
c. A concentric hole in the briquette helps in combustion because of sufficient
circulation of air.
18
d. The machine is light compared to the piston press because of the absence of
reciprocating parts and flywheel.
e. The machine parts and the oil used in the machine are free from dust or raw
material contamination.
f. The power requirement of the machine is high compared to that of piston press.
b) PISTON PRESS TECHNOLOGY
In the piston press, pressure is applied discontinuously by the action of a piston on
material packed into a cylinder. Piston-presses can be driven either by mechanical means
from a massive flywheel via a crankshaft or hydraulically. The mechanical machines are
usually larger, ranging in size from 0.15 to 0.3t/h, whilst hydraulic machines normally
range up to 0.25t/h though some models are somewhat larger. Mechanical presses
generally produce hard and dense briquettes from most materials whilst hydraulic
presses, which work at lower pressures, give briquettes, which are less dense and are
sometimes soft and friable. Hydraulic piston press is different from the mechanical piston
press in that the energy to the piston is transmitted from an electric motor via a high-
pressure hydraulic oil system. This machine is compact and light. Because of the slower
press cylinder compared to that of the mechanical machine, it results in lower outputs.
Piston presses are reliable, once they have been installed properly with dies shaped
correctly for the raw materials used. Problems arise if the die has not been shaped
correctly or if the feeding mechanism has not been sized for the material to be used.
Below are the advantages and disadvantages of the piston press technology.
a. There is less relative motion between the ram and the biomass hence, the wear of
the ram is considerably reduced.
b. It is the most cost-effective technology. Some operational experience has now
been gained using different types of biomass.
c. The moisture content of the raw material should be less than 12% for the best
results.
d. The quality of the briquettes goes down with an increase in production for the
same power.
19
e. Carbonization of the outer layer is not possible. Briquettes are somewhat brittle.
Fig.2: Piston press system
3.3 BIOMASS DENSIFICATION
Utilization of agricultural and forestry residues is often difficult due to their uneven and
troublesome characteristics. This drawback can be overcome by means of densification,
i.e. compaction of the residues into products of high density and regular shape.
Densification has aroused a great deal of interest worldwide in recent years as a technique
of beneficiation of residues for utilization as energy source. Depending on the type of
equipment used, densified biomass can be categorized into two main types: briquettes
and pellets. Briquettes are of relatively large size (typically 5-6 cm in diameter and 30-40
cm in length) while pellets are small in size (about 1 cm in diameter and 2-4 cm in
length). Densified biomass produced in developing countries is mostly in the form of
briquettes, which are used directly to substitute fuel wood or for carbonizing to produce
briquetted charcoal; use of pellets so far appears to be insignificant. Because of small and
uniform size, pellets are particularly suitable for automatic auger-fed combustion
systems; densified biomass used in developed countries is mostly in the form of pellets.
20
a) DENSIFICATION TECHNOLOGIES
Two common types of briquetting presses employed in developing countries are heated
die screw press and piston press. It appears that heated-die screw press technology was
invented in Japan in mid-1940s. By now, the technology has spread to most of its
neighboring and nearby countries, particularly Korea, China, Taiwan, Vietnam, Thailand,
Malaysia, Philippines, Bangladesh, etc. where heated-die screw-press briquetting
machines are used almost exclusively. Also, the design of screw-press briquetting
machines appears to have evolved and been adapted to suit local conditions in different
countries. The piston press technology is the dominant technology in India, Brazil and
Africa. While these are locally made in India and Brazil, the African machines appear to
be mostly imported. Compared to piston-press machines, heated-die screw press
machines have smaller capacity but produce stronger and denser briquettes. Screw press
technology is therefore more suitable if the briquettes are to be carbonized to obtain
briquetted charcoal. Besides, conventional binder less briquetting, low-pressure cold
briquetting using binder has also been tried in some places. Most noteworthy among
these is the carbonization-briquetting process, in which biomass is first carbonized and
the resulting charcoal is briquetted using a suitable binder. The process has been tried for
cotton stalk in Sudan and coffee husks in Kenya; limited use of this technique has been
reported in India and Nepal. Briquetting of bagasse using molasses as binder has been
reported to have had limited success in Sudan. Another low-pressure binder less
briquetting process involves mixing pulverized chopped and decomposed biomass with
water into a pulp. The pulp is pressed inside a perforated pipe to get 4-inch diameter
cakes, which are sun-dried to get briquettes (Stanley, 2002). The basic press is made on
site and the product is normally of lower density compared with conventional briquettes.
A non-profit organization, Legacy Foundation, is currently involved in dissemination of
the technology. Briquette made from a mixture of pulverized coal, biomass and slaked
lime has been introduced by a Japanese company in two Asian countries, China and
Indonesia. The briquettes, called coal-biomass briquettes are produced by using a roll-
press. It is claimed that the use of the desulfurizing agent (slaked lime) and biomass
results in cleaner combustion of the briquettes in stoves and less of ash compared with
coal or coal briquettes (Kobayashi, 2002). As indicated earlier, pelletizing is the major
21
densification technology employed in developed countries. Capacity of these plants is
much larger, being in the range 1-30 tons per hour.
b) RAW MATERIALS FOR BIOMASS DENSIFICATION
The most common raw materials for heated-die screw-press briquetting machines are
saw dust and rice husk. Some other raw materials, e.g., coffee husk, tamarind seeds,
tobacco stems, coir pith and spice waste have also been used in India (Vempaty, 2002).
Sawdust is practically the only raw material used for producing briquettes, which are
subsequently carbonized; it is the dominant raw material in Malaysia, Philippines,
Thailand, and Korea. On the other hand, rice husk is the only raw material used in
Bangladesh. Piston press briquetting machines use a wide range of pulverized raw
materials; in India, these include saw dust, ground nut shell, coffee husk sugar cane
bagasse, cotton stalks, sun flower stalks, spent coffee waste etc. Peanut shell and cotton
stalk appear to the most important raw materials in Africa. The raw material mostly used
in developed countries is sawdust and wood wastes.
c) STATUS OF BIOMASS DENSIFICATION IN INDIA
About 70 biomass briquetting machines were installed in India by 1995; since then
briquetting has been gaining acceptance slowly but steadily. Two types of briquetting
presses are common in India, piston presses and heated-die screw presses. The capacity
of piston presses normally lies in the range 400-2000 kg/hr (Vempathy, 2002); the
number of machines of this type installed so far is about 150. Heated-die screw-press
briquetting machines are also available commercially; the number of machines of this
type installed so far is about 60. One manufacturer offers preheated biomass briquetting
systems.
Indian Renewable Energy Development Agency Limited (IREDA) is a Public Limited
Government Company established in 1987, under the administrative control of Ministry
of Non-Conventional Energy Sources (MNES) to promote, develop and extend financial
assistance for renewable energy and energy efficiency/conservation projects. IREDA
support for briquetting in the form of loans since its inception till March 2001 was INR
174 million (47 INR ~ I USD). The largest plant financed by IREDA has a capacity of
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12.2 tonnes per hour. With assistance of USAID, three briquetting plants have been set in
Rajasthan state of India. These plants use mustard stalk as the raw material and combined
capacity of about 45,000 tonnes per year; 12-14 briquetting factories with a capacity to
produce 200,000 tons per year are being planned.
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CHAPTER-4
METHODOLOGY
Briquetting process is a process of compaction of residues into a product of higher density
than the original raw material. In developing countries such as Malaysia, Philippines, and
Thailand, biomass briquettes are mostly carbonized to obtain briquetted charcoal. The
briquette carbonization production process consists of a carbonization stage and a
compaction stage. In the carbonization stage, a biomass material such as wood is heated
(Approximately 450 c) but is not given enough oxygen for the material to burn. This
stage produces charcoal. In compaction stage, the charcoal is crushed into very small size
as a carbonized powder. Then the powder and some binder are completely mixed at a
predetermined mixing ratio. After that the mixture is brought into the molding machine to
form the briquettes.
The briquettes are dried and cooled. Each step of the process is detailed as follows:
Carbonizing: The raw material is carbonized by less air combustion in
carbonization furnace with low temperature approximately 450c
Crushing: Carbonized material is crushed into very small size by using crushing
into very small size by using crushing machine.
Mixing: Approximate proportions of raw materials and binder are mixed
thoroughly into the mixing container
Briquetting: The mixture is pressed or produced into finished products.
Briquetting machine is used for briquetting charcoal fine into charcoal briquettes.
Drying: The briquettes were dried under sunlight
The important manufacturing process of the charcoal briquette production is crushing,
mixing and briquetting, which requires three machines in the production process. This
research is to develop a biomass briquetting machine which includes crushing, mixing
and briquetting process in a machine. In this way, production area and production cost of
biomass briquettes can be reduced by using the newly designed machine. It is a simple
energy and money saving device made out of locally available materials. There are
several methods available for briquetting biomass. In developing countries, the well-
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known briquetting method that is suitable for small-scale applications is the screw-press
briquetting. The raw material from the hopper is conveyed and compressed by a screw in
the briquetting machine. This process can produce denser and stronger briquettes
compared with piston presses.
Fig.3: Process overview
4.2 Developing machine
The compact briquetting machine has been designed with the aim of eliminating
individual machines, reducing material handling, manpower and space, and improving
productivity. The important matter is that the obtained briquette quality should be in an
acceptable range. We design the compact screw-press biomass briquetting system which
combines three functions including crushing, mixing and briquetting in a single unit. The
briquetting machine designed has a capacity of about 90 kg/hr and is driven by a 0.5 HP
electrical motor.
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The briquetting system as the proposed design (a compact machine and one worker):
carbonized material is transferred to a compact machine and then the binder is added into
the mixing container. Briquettes are extruded out at the die exit. Finally, the briquettes
are then cut and dried before sending to its store. In doing so, it helps to reduce worker,
material handling, transfer time, space and production time. That leads to improve its
productivity.
a) Crushing system: hammer mill is used to crush carbonized material into
carbonized powder. Carbonized powder is then sieved during grinding, at 1.13
kg/min. Size of carbonized powder obtained from this system is less than 1.7 mm.
Fig.3 crushing system
b) Mixing System: Carbonized powder and cassava starch as a binder are mixed
homogeneously by rotating stirrer in a container. After that, the mixed material is
then sent into a briquetting process.
Fig.4: mixing system
c) Extrusion system: In a briquetting process, the mixed material is extruded by a
screw extruder which acts as a continuous feeder and driven by motor. The 26
volume of the material is decreased as it is transferred from the hopper to the die
exit. This is achieved by decreasing the diameter of the threaded shaft and
cylinder gradually starting with a uniform diameter at the feeding position and
decrease gradually to a minimum value at the die position. Figure shows the
design of the screw.
Fig.5 extrusion system
After finishing the development of such a machine, the capacity and functional testing of
the machine are performed. In testing, the briquettes are produced continually by the
machine fabricated at full capacity and an appropriate ingredient ratio of the mixture is
50% carbonized powder, 40% cassava starch and 10% water. It is found that the machine
can produce the briquettes at high production rate. It is also found that the machine can
work appropriately as designed.
Fig.6: Complete assembly of briquetting machine
Table 6: PARTS OF MACHINE
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Serial no. Part Name Amount Serial no. Part Name Amount
1. Structure 1 9. Mixing
handle
1
2. Crushing sys 1 10. Motor 1
3. Bearing 7 11. Mixing
container
1
4. Charcoal
fine chamber
1 12. Crushing
pulley
1
5. Mix. cover 1 13. Pulley 2
6. Cylinder 1 14. Pulley 1
7. Feeder 1 15. Mix. Pulley 1
8. Extruder 1 16. Pulley 1
d) Characterizing property of the briquettesHeating value: According to the ingredient ratio it is assumed that our machine
will give approximately 2000-3000 calories per gram.
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CHAPTER 5
DESIGNING
List of component
S.No. Name No. off
1 Frame 1
2 Crusher Cover 1
3 Hammer mill 1
4 Siever 1
5 Mixing chamber 1
6 Stirrer 1
7 Hopper 1
8 Extruder cover 1
9 Extruder 1
10 Shaft 4
11 Pulley 5
12 Bearing 8
13 Motor 1
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1. FRAME: For any machine it is very important to have a solid and firm base. For our machine we
have taken Cast Iron as a frame material and ‘L’ section of thickness 5 mm and width 30
mm.
Material: Cast Iron
Section: ‘L’ Type
Thickness: 5 mm
Width: 30 mm
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CRUSHER COVER:
Sheet: steel
Thickness: 3 mm
HAMMER MILL:
Blade material: steel
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SIEVER:
Material: steel
Sheet thickness: 2 mm
FINE CHAMBER:
Material: tin
32
MIXING CHAMBER:
Material: tin
Thickness: 3 mm
STIRRER:
Material: Cast Iron
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HOPPER:
Material: Tin
EXTRUDER COVER:
Material: tin34
EXTRUDER:
Material: Aluminum
Fabrication: casting
PULLEY 1:
a) Diameter = 100 mm
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Fabrication: casting
Dimensions of pulley:
σ t =ρv2
=7200*(πDN /60)2
=7200 * (π*0.1* 1500/60)2
=444132.2 N/m2
Width of belt (b) = 20 mm
Face of Pulley = 1.25b = 1.25*20 =25mm
Thickness of Pulley (t) = (D/300) + 2 mm to (D/200) +3 mm
=2.91 mm
No. of arms = Solid
P= power = (2πNT /60)
Let P =1.5 Hp
T = (1.5 *60) / 2π*1500
T=7.12 Nm
WT= 2T/R = 284.8 N
M = 2T =14.24 Nm
Dimensions of Hub –
Diameter of Hub (d1) =1.5 d +25mm = 62.5 mm
Or d1=2d =50 mm
Length of Hub (L) =π d2 = 39.275mm
PULLEY 2:
Diameter: 160 mm
Fabrication: casting36
Dimensions of pulley:
σ t =ρv2
=7200*(πDN /60)2
=7200 * (π*0.16* 1000/60)2
=505323.745 N/m2
Width of belt (b) = 20 mm
Face of Pulley = 1.25b = 1.25*20 =25mm
Thickness of Pulley (t) = (D/300) + 2 mm to (D/200) +3 mm
=3.165 mm
No. of arms = Solid
P= power = (2πNT /60)
Let P =1.5 Hp
T = (1.5 *60) / 2π*1000
T=10.68 Nm37
WT= 2T/R = 854.4 N
M = 2T =21.36 Nm
Dimensions of Hub –
Diameter of Hub (d1) =1.5 d +25mm = 62.5 mm
Or d1=2d =50 mm
Length of Hub (L) =π d2 = 39.275mm
PULLEY 3:
Diameter =60 mm
Fabrication: casting
Dimensions of pulley:
σ t =ρv2
=7200*(πDN /60)2
=7200 * (π*0.06* 1000/60)2
=71061.15 N/m2
Width of belt (b) = 20 mm
Face of Pulley = 1.25b = 1.25*20 =25mm
Thickness of Pulley (t) = (D/300) + 2 mm to (D/200) +3 mm
=2.75 mm
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No. of arms = Solid
P= power = (2πNT /60)
Let P =1.5 Hp
T = (1.5 *60) / 2π*1000
T=10.68 Nm
WT= 2T/R = 854.4 N
M = 2T =21.36 Nm
Dimensions of Hub –
Diameter of Hub (d1) =1.5 d +25mm = 62.5 mm
Or d1=2d =50 mm
Length of Hub (L) =π d2 = 39.275mm
39
PULLEY 4:
Diameter= 200 mm
Fabrication: casting
Dimensions of pulley:
σ t =ρv2
=7200*(πDN /60)2
=7200 * (π*0.2*250/60)2
=49348.02 N/m2
Width of belt (b) = 20 mm
Face of Pulley = 1.25b = 1.25*20 =25mm
Thickness of Pulley (t) = (D/300) + 2 mm to (D/200) +3 mm
=3.33 mm
No. of arms = 440
P= power = (2πNT /60)
Let P =1.5 Hp
T = (1.5 *60) / 2π*250
T=42.73 Nm
WT= 2T/R = 213.65 N
M = 2T/n =21.365 Nm
Dimensions of Hub –
Diameter of Hub (d1) =1.5 d +25mm = 62.5 mm
Or d1=2d =50 mm
Length of Hub (L) =π d2 = 39.275mm
PULLEY 5:
Diameter= 315 mm
Fabrication: casting
41
Dimensions of pulley:
σ t =ρv2
=7200*(πDN /60)2
=7200 * (π*0.315*166/60)2
=53985.8 N/m2
Width of belt (b) = 20 mm
Face of Pulley = 1.25b = 1.25*20 =25mm
Thickness of Pulley (t) = (D/300) + 2 mm to (D/200) +3 mm
=3.812 mm
No. of arms = 4
P= power = (2πNT /60)
Let P =1.5 Hp
T = (1.5 *60) / 2π*166
T=64.36 Nm
WT= 2T/R = 204.32 N
M = 2T/n =32.18 Nm
Dimensions of Hub –
Diameter of Hub (d1) =1.5 d +25mm = 62.5 mm
Or d1=2d =50 mm
Length of Hub (L) =π d2 = 39.275mm
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FUTURE SCOPE
Our machine which combines three functions including crushing, mixing and briquetting in a single unit is able to improve the production cost and productivity. A small light weight fuel briquette machine has been successfully designed and we are expecting to produce 200 briquettes per hour and it will reduce the cutting down of trees for fuel-wood purposes, thereby preventing deforestation and erosion.
The product (briquette) which we will obtain from the machine can be used as alternate to fuel-wood in domestic cooking and small-scale industries. The machine will enable agricultural waste to be removed from the environment, thereby preventing environmental pollution.
Due to availability of limited resources we have used extra material for more factor of safety which will cost us more but our design is as safe as any other already existing in market and expecting to be more efficient.
In India briquetting technology was introduced in late 80’s thereafter there is very slow and study development in this field. This is only due to lack of knowledge of the citizen of India. But now the time has come to take it seriously if we want to save our valuable natural resources.
Our machine is expecting to be capable of producing highly intensified and pressurized briquettes which will be very efficient in terms of energy.
Further modification can be done on the basis of load used and the size of the briquettes being manufactured.
Binder is very important for efficiency improvement and for densification of the briquettes so for effective improvement the effect of the binder content on the combustion potentials of the briquette needs to be investigated further.
43
REFERENCE
1. M.B Oumarou and Oluwole F.A [1]Mechanical Engineering Department, University of Maiduguri, Bornu State
2. Bhattacharya, S.C. (2002).[2] A Global Review with Emphasis on Developing Countries, paper presented in First World Pellets Conference, Stockholm, Sweden.
3. Bhattacharya, S. C. Augustus, L. M. and Rahman Md. M. (2002). A Study on Improved Biomass Briquetting, combines three functions including crushing, vol.6 (2), 2002.
4. P.D. Grover & S.K. Mishra et al April 19969- biomass Briquetting: technology and practices.
5. https://www.google.com/briquettingmachine /6. http://www.tnau.ac.in/ 7. http://en.wikipedia.org/wiki/briquetting machine/
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APPENDIX1. Complete views of briquetting machine
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