5. Biomass Potential in India
• Biomass energy has been attracting attention as an
energy source since zero net carbon dioxide
accumulation in the atmosphere
• Among several kinds of biomass, agro residues have
become one of most promising choices
• It is estimated that around 650-700 mt of agricultural
residues produced in a year
• Of which 350 mt of residues are surplus - burnt in open
field
• These residues can yield huge amount of energy
containing fuel if it is used appropriately
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
6. Necessity of Briquetting
• Compaction of biomass in the form of solid fuels has
yielded a simple solution
• Complex problems in the biomass are
• low density, high volume and expensive handling,
transportation and storage
• Compacted fuel is more or less similar to coal
• Potential to replace the conventional solid fuels and even
diesel to meet the local energy needs of various sectors
• Briquettes burns as good as coal,
• leave less ash content
• emit less or no smoke and
• have low ignition point
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
7. Biomass materials suitable for densification
• Commonly used raw materials for briquetting in India
• Agro residues such as saw dust, rice husk, tapioca waste,
groundnut shell, cotton stalks, pigeon pea stalks, soybean
stalks, coir pith, mustard stalks, sugar cane bagasse, wood
chips, tamarind pod, castor husk, coffee husk, dried tapioca
stick, coconut shell powder
• Factors influence on the selection of raw materials are -
moisture content, particle size
• flow characteristics, ash content and
• availability in the locality
• Moisture content in the range of 10-15% is preferred
• Ash content (4%) preferred of biomass affects its slagging
behavior
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
8. Densification
• Biomass densification may be defined as compression or compaction to
remove inter and intra-particle voids
• 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.
• Five commercial processes
• Baling
• Pelleting
• Cubing
• Briquetting
• Extrusion
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
9. Compression baling process
• Reduce biomass volume to one-fifth its loose bulk.
• Useful for agricultural biomass and certain types of forest
biomass. e.g. crops from energy plantations, logging residues.
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
11. Densification Technique
1. High pressure compaction
2. Medium pressure compaction with a heating device
3. Low pressure compaction with a binder
Piston press densification
Screw Press densification
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
12. Advantages of Briquetting
• Increases the net calorific value of material per unit volume
• End product is easy to transport and store
• Fuel produce is uniform in size and quality
• It helps solve the problem of residue disposal
• It helps to reduce deforestation by providing a substitute for
fuel wood.
• Eliminates the possibility of spontaneous combustion waste
• Reduces biodegradation of residues
Disadvantages
• High investment cost and energy input to the process
• Undesirable combustion characteristics such as poor
ignitability, smoking, etc are often observed.
• Tendency of briquettes to loosen when exposed to water or
even high humidity weather
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
13. Piston press densification
• A reciprocating piston pushes the material into a tapered die
• A controlled expansion and cooling of the continuous briquette
is allowed in a section following the actual die
• Most common type - cylindrical piston and die dia 20-125 mm
• Biomass feedstock is a key factor in determining the
functioning of the process and briquette quality
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
19. Biomass Husk for combustor
feedstock for drying coconut
Dr.Mahendiran
TNAU
@
Kavaratti
UTL
Feb
2020
20. Brequetteas fuel for BiomassCombustor
Dr.Mahendiran
TNAU
@
Kavaratti
UTL
Feb
2020
21. Screw Press densification
• Screw through a taper die which is heated externally to reduce
the friction
• Material is fed continuously into a screw which forces the
material into a cylindrical die
• heated to 250-300 °C to raise the temperature to the point
where lignin starts flowing and pressure builds up smoothly
• High quality briquettes than piston-press unit
• Power requirement per tonne of briquette produced is high
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
22. Comparison of piston press and
screw press densification
Parameters Piston press Screw Press
Optimum moisture content of
raw material (%) 10-15 8-9
Wear of contact parts low in case of ram and die high in case of screw
Output from the machine In strokes Continuous
Power
consumption(kWh/ton)
50 60
Density of briquette(gm/cm³) 1-1.2 1-1.4
Maintenance High Low
Combustion performance of
briquettes
not so good very good
Carbonization to charcoal not possible makes good charcoal
Suitability in gasifiers not suitable Suitable
Homogeneity of briquettes non-homogeneous Homogeneous
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
23. Briquette Analysis
• Détermination of Combustion properties
• Heating Value
• Determination of bulk density
• Determination of water content
• Measurement of strength and durability
• Water resistance
• Impact resistance
• Water stability test
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
24. Utilization of briquetted fuel
• Replacement for conventional fuel
• Wood, coal, dung, cake, LPG and kerosene – mostly
used fuels for domestic cooking
• For domestic cook stoves 12-25 mm dia briquettes are
more suitable.
• Used in boilers, gasifiers, furnaces for thermal
applications, 50-60 mm size preferred
• 60-90 mm size are being used in big boilers and
gasifiers
• Briquette based gasifiers can be used for running 100%
producer gas operated electric generating sets.
• Ave. 1 kg biomass briquette can produce 1 kWh of
power.
ERG
211
Lect-5
Biomass
Briquetting
Dr.RM
