Installation of Green boiler is an initiative to replace one of a coal fired boiler with a biomass residue fired boiler for steam generation. Boiler is designed to fire biomass residues (wood bark, tops and lops) from the plantations of pulpwood as the major fuel (90% of the total biomass residue used), along with agricultural crop residue from paddy, cotton, chilly, maize, red gram. A small amount of chip dust will also be fired in the boiler which is a biomass derived as by-product of the process of chipping of wood in the paper plant.
Green boiler utilizes the biomass in absence of which the equivalent amount of biomass residue would have been burnt in an uncontrolled manner without utilizing them for energy purposes.
Boiler: Installation of boiler, designed to fire fuel mix of biomass and F grade coal at 70:30 ratio.
The green boiler contributes to the generation of green energy, which prevents the firing of coal which would have been used in the absence of the boiler. Coal will be used to the extent of 30% of energy needs to support the combustion.
Green boiler will also help to avoid the methane emission which would have happened due to decay of biomass residues in the plantation sites. The biomass for the steam generation in the boiler will be obtained from the following sources:
a) Tree barks from the ITC’s plantation
b) Lops and tops from ITC’s plantation.
c) Chip dust from the ITC’s in-house wood chipping unit.
d) Rice husk from nearby agricultural fields.
e) Cotton stalk from the nearby agricultural fields.
f) Chilly stalk from the nearby agricultural fields.
The above biomass used in the project boiler (obtained from the agricultural fields and plantation sites) otherwise would have been dumped or left to decay under clearly anaerobic conditions.
Besides other points, it has been stated that the project technology (i.e. Biomass residue fired boiler) would result in better fuel combustion and would result in lesser ash generation as the ash content in biomass is less than the ash content in coal.
COAL: Coal savings through fuel switch
CDM: Reduction in CO2 emission due to saving coal generates more then 73,000 CER per annum through CDM
Utilization of available biomass improves the biomass component in the unit’s primary fuel mix. Unit Bhadrachalam has fuel mix of 55% fossil and 45% carbon neutral (biomass) after commissioning of pinnacle and PM6.
Installation of biomass fired boiler significantly improves the biomass component, reducing carbon foot print.
As total steam generation remains same before and after Green Boiler and due to usage of biomass in place of coal, fly ash generation will reduce,. nearly 20,000TPA of fly ash generation will be reduced resulting in reduction of solid waste generation.
ENVIRONMENTAL IMPACT OF THE PROJECT
As general rule, considering surface moisture & lower GCV, 1 MT of coal is replaced by 2 MT of biomass consumption. Hence, consumption of every 1MT of biomass reduced coal consumption by 0.5MT, resulting
Social Benefit: Source of revenue for farmer by selling the biomass from their fields which otherwise is burnt without realizing the energy value.
Environmental Benefit: Lower GHG emissions in manufacturing pulp & paper resulting lower carbon footprint
Economic Benefit: Lower ash generation means lesser handling cost.
Ash: Biomass has ash content less than 10% compared to 55% in F grade coal, under normal operation, 55% of the steam is generated by biomass and balance 45% by coal to meet CDM requirement, thus reducing the fly ash generation.
Emission Reduction: GHG emission is reduced to the extent of fossil fuel replacement by biomass.
Liquid waste: Liquid effluent remains same with and without project as CFB6 is stopped as standby boiler.
Dust emission: Biomass preparation plant is proposed outside the mill premises with dust extraction system to recover and utilize the dust for boiler. Sized biomass shall be conveyed by closed belt conveyors to boiler to avoid spill over and dust.