Green Coal Project
Bio fuel is made from food and agro waste and is essentially compressed block which has higher calorific value and bulk density than the original bio waste from which it is made. Thus it becomes easier & cheaper to handle and transport.
Green Coal is Torrefied Bio Fuel in Pellet or briquette form.
During Torrefication at 250-300 Deg C, with control of heating and atmosphere, leads to total loss of moisture and partial (20%) loss of volatile matter, where most of the oxygen in biomass is removed This results in brittle, hydrophobic and higher calorific value green coal material.
The hydrophobic Bio fuel, i.e., green coal, can be stored in open atmosphere without any special protection –
Green coal in pellet form has characteristics compatible with Coal (ie. Heating Value, Grind ability, Bulk Energy density, Hydrophobic, easy transportation, Co-firing in a pulverised coal fired Power Plant, cement kilns, Coke and Steel Industry (for charred Biomass)
Green Coal has improved combustion which is important when used as a heating fuel.
Combustion Quality as achieved when burning a certain fuel is measured by different factors such as : Heating Value ,moisture content, reactivity, particle size and importantly ash content.
Green coal has a higher reactivity, largely due to high amounts of volatile matter (55-65% as compared to 10-12% for Coal. So, it can work as smokeless fuel.
The driving force is lowering Green House Gases.
Main commercial applications for Torrefied Biomass can be found in
1) Co-firing in coal fired power plants ,
2) Industrial Heating as in Combustion ,
3) Domestic Heating in Cooking stove and Boilers for Hot water etc.
It would be smoke less, generate far less ash and provide heat comparable to coal
without having its disadvantages.
4) Small scale Domestic Boilers used for heating water or space in
residential and commercial buildings can be an application because of
higher Energy & Bulk Density.
5) Can also be used in Steel Plant Blast Furnaces and Cement kilns.
Green coal has higher calorific value as follows:
1) Wood – 9-12 MJ/kg
2) Wood Pellet - 15-18 MJ/kg
3) Green Coal 21-24 MJ/kg),
4) Coal 23-28MJ/kg
Green coal has has higher Density (kg/m3)
1) Wood 0.20-0.25
2) Wood pellet 0.55-0.75
3) Green Coal . 0.75-0.85
4) Coal 0.80-0.85
Green coal has higher Energy Density (GJ/m3)
1) Wood 2.0-3.0
2) Wood Pellet 7.5-10.4
3) Green coal 15.0-18.7
4) Coal 18.4-23.8
The commercial market is rapidly developing for green coal and from the trend in Europe, pellet requirement as a partial substitute for coal is exploding.
The main reason is to contain greenhouse gases.
At present 5 Million tons/yr is the actual export of wood pellets from Canada to Europe, and is going up to 20 M tons by 2020. This is the forecast.
If just a fraction of this is Torrefied, it will be huge quantity and a justification for Indian market to produce green coal and not just stop with white pellets.
Conversion of bio waste into green coal has additional advantage of getting the best bio fuel without exploiting wood. A highly profitable commercial venture with double social and environmental advantage of disposing off the waste and of also reducing the green house effects.
Vegetable waste along with the left over foods from air lines, hotels and restaurants will be fed into hopper of a suitable conveyor which would lead these into a particle size reduction system.
The feed would be reduced to a size less than 1 mm. This would then be filtered for removing excessive moisture, dried in a Continuous Conductive Dryer ( CCD ) and compressed to form pellets of solid bio fuel of required sizes of 10 – 12 % moisture. This compressed & dried bio mass can converted, if desired, into green coal of 0 % moisture in a torrefactor.