Biomass
Biomass is organic material, which has stored solar energy from sunlight in the
form of chemical in the plants through the process called photosynthesis. Biomass
fuels include Agricultural Wastes, Crop Residues, Wood, Woody Wastes & Organic Wastes
etc. Unless like fossil fuels Biomass does not add carbon dioxide to the atmosphere
as it absorbs the same amount of carbon while growing. It is the cheapest, eco-friendly,
renewable source of energy.
Biomass Gasification converts solid biomass into more convenient gaseous form. The
ratio of air-to-fuel required for the complete combustion of the biomass is 6:1
to 6.5:1, which defined as stoichiometric combustion with the end products being
CO2 and H2O. In gasification the combustion is carried at sub-stoichiometric conditions
with air-to-fuel ratio being 1.5:1 to 1.8:1. The gas so obtained is called Producer
gas, which is combustible having a calorific value of 4.5-5.0 MJ/kg, with an average
composition of CO : 20 + 1%; CH4 : 3 + 1%, H2 : 20 + 1%, CO2 : 12 + 1% and rest,
N2. This process is made possible in a device called biomass gasifier. A biomass
gasifier system mainly comprises of a reactor, where the combustible gas is generated
and the gas is made available for power generation / thermal application after the
required cleaning and cooling process.
Using the gas obtained from biomass fuel, it is possible to operate a diesel engine
on Dual Fuel Mode with marginal changes to the air inlet or in a 100% Producer Gas
Engine. In dual fuel mode, diesel substitution of the order of 80 to 85% can be
obtained at nominal loads. The recent developments have made possible the operations
of Spark ignited gas engine using gas obtained from biomass fuel alone. The mechanical
energy thus derived can be used directly to energizing mechanical device or by coupling
with an alternator for electrical power generation, either for local consumption
or for grid synchronization.
Thermal Applications utlizing biomass technology
For processes, which require thermal energy, biomass gasifiers can be a good option
as a gas generator, and retrofitted with existing devices. Producer Gas has the
advantage of better and finer power control, more efficient and environment friendly
when compared to that of solid fuels. Burning of 1 m3 of gas obtained
from biomass fuel in the burner will release thermal energy of the order of 4.5
to 5.0 MJ. Flame temperatures as high as 12000 C can be obtained by optimal
pre-mixing of air with the gas obtained through biomass gasification.
Few of the applications where retrofit is possible are:
- Dryers: Drying is the most essential process in industry like tea, rubber,
cardamom etc. It requires hot gases in the range of 1200-1300
C. In this case biomass gasifier could be an ideal solution, where hot gas after
combustion can be diluted with the required quantity of secondary air, so as to
lower its temperature to the desired level for operation.
- Kilns: Baking of tiles, potteries require temperature range of 8000
- 9500 C. In conventional practices they burn large quantities of wood
in an inefficient manner. Biomass gasifier could be suitable for such applications,
which provides a better control of temperature with smokeless operation thereby
enhancing the product quality.
Cogeneration / Combine Cycle
Through Biomass Gasifier is in itself can generate cheaper power and also the heat
energy from the engine exhaust gas can be effectively utilzed to make the power
generation cost to almost nil. The engine exhaust can be used in applications like
drier, steam / hot water / hot air generator, thermic fluid heaters, Vaour Absorption
Chillers and any thermal applications. This makes the biomass gasifier based power
plants still more attractive.
We will be getting around 6-7% of partially activated Charcoal as byproduct from
our biomass gasifier, which can be sold in the market and will generate additional
revenue. Also we have 80% accelerated depreciation benefit for Biomass Gasifier
based projects since this being renewable source of energy. Apart from this we can
avail CDM benefits for these projects. Without increasing your production or compromising
your quality, you can reduce your production cost and increase your profitability
by reducing your energy cost.