Every year millions of tons of agricultural wastes and forest residues are generated. These are either wasted or burnt inefficiently in their loose form causing air pollution. Handing and transportation of these materials is difficult due to their low bulk density. These wastes can provide renewable source of energy by converting in to high density fuel briquettes with out addition of any binder

Briquettes have high specific density (1200kg/m3) and bulk density( 800kg/m3) compared to 60 to 180 kg/m3 of loose bio mass. These can stand the ardors of long distance transport. Loading/ unloading and transportation cost are much less and storage requirements is drastically reduced. Compared to firewood or loose bio- mass, briquettes give much higher boiler efficiency because of low moisture and density


Briquettes produced from briquetting of biomass are fairly good substitute for coal, lignite, firewood and offer numerous advantages.



  • Briquettes are cheaper than coal
  • Oil,coal or lignite once used can´t be replaced
  • High sulfur content of oil and coal, when burnt, pollutes the environment. There is no sulfur in briquettes.
  • Bio mass briquettes have a higher practical thermal value and much lower ash content(2-10% compare to 20-40% in coal).
  • There is no fly ash in burning briquettes
  • Briquettes have a consistent quality, have high burning efficiency are ideally sized for complete combustion. Combustion is more uniform compared to coal and boiler response to changes in steam requirements is faster due to higher quantity of volatile matter in briquettes.
  • Briquettes are clean to handle and can be packed in bags for ease of handling and storage.
  • Briquettes are usually produced near the consumption centers and supplies don´t depend on erratic transport from long distances.


Briquetted fuel has some shortcoming also:

It can´t withstand direct contact with water hence storage facility for keep briquettes required. Maximum attainable temperature is 1000`C due low carbon content. Burning capacity per unit volume of furnace is low compared to coal.



The demand of fuel briquettes is increasing as the use of the briquettes is spreading and people becoming aware of its availability and advantages. Briquetted fuel can be used as a substitute of coal or firewood. At present it is being used in the following areas.

1.Tyre Retrading units
2.Tea processing units
3.Boiler for raising steam in chemical, Textile processing industries
4.Hotels and restaurants for raising steam
5.Dryers and ovens for generation of hot air and many areas where firewood, Leco and coal used.

We agni agro industries having three briquetting plants situated in tamilnadu in the district of erode and coimbatore to cater the demands of industries locally.




Sl. No.
Fire wood
Coal B
1. Calorific value 2500 to 3000 4200 to 4500 4500 to 6000
2. Ash 20 to 28 % 0.5 to 6 % 25 to 50%
3. Pollution,Poisonous
effluent Smoke
Smoke No Smoke
No Sulphur
phosphorous fumes
4. Moisture 25 to 35 % 8 % 10%
5. Cost Rs. 3.5 /kg Rs.5.5 /Kg Rs. 7 /kg
6. Efficiency 50% 75% 70%
7. Wastages 20% 10% 15%
8. Labour usage Require maximum persons in handling and cutting Single person is enough Require two persons
9.. Boiler efficy Require regular maintainance normal Fly ash deposit on tubes high wear & tear
10. Handling Tough require more areas Easy because of packed material Tough


Agro waste briquettes have certain benefits over coal like

  • Easy handling, packing and transportation of briquettes can be made in any conventional length and diameter.
  • Low ash content( below 10%) in comparison to coal( 25 to 40%) resulting least boiler ash disposal problems.
  • Regular supply of briquettes do not suffer from transportation bottle necks as the plant can be set up near raw material source and selling areas.
  • There will be no corrosion effect on boiler equipments resulting in negligible maintenance cost. Coal on the other hand produces sulpher dioxide, which on mixing with moisture produces sulphuric acid an corrosive acid.
  • Compare with coal even in terms of cal. Value per rupee
  • It has low ignition point, when compared to leco and coal
  • It gives sustained combustion and more efficient combustion then loose agro wastes
  • It is a clean fuel.
  • No gas and effluents like coal. So no health hazards.
  • Easy handling compared to loose husk and fire wood.
  • Low ash content. So less ash handling.
  • Can be mixed with coal and fire wood of inferior quality which improves burning.
  • Prevents environmental destruction due cutting off trees.

Proximate analysis of AGNI briquettes
Ultimate analysis of AGNI briquettes
Moisture 7.20 to 8 % Carbon 47.10 %
Volatile matter 62 to 68 % Ash content 6.78 %
Ash content 6 to 8 % Nitrogen 1.87 %
Fixed carbon 20 to 26 % Sulphur 0.26 %
    Oxygen ( by differ) 38.86 %