The observed increase of the pollutants SOX, NOX and CO2 concentrations in the atmosphere, with its negative effect on the global climate, is predominantly caused by the combustion of fossil fuels. Fossil fuels are the major source of energy in the world and will continue to be so for the foreseeable future. Major efforts are therefore being invested in making use of these fuels more efficiently and environmentally acceptable As industrialization increases, so will the amount of waste materials and the environmental problems associated with their disposal. Waste generation in ever increasing quantities is an important issue facing the world.. As regards to India, agricultural wastes like biomass, cane trash, rice husk is being used for firing in harvest season when they are abundantly available by some industries just to utilize them. They have not been fired along with coal. The above mentioned problems of increasing pollution and waste generation can be tackled by using coal waste Co-firing technology which can offer an environmentally sound, economic approval to both waste remediation and energy production. Co-firing of coal with agricultural wastes has been shown to be the lowest cost method for generating GREEN POWER and at the same time reducing the emissions in to the atmosphere. This paper discusses the results of the experiments conducted in a 18.68 MW power plant in Tamilnadu, with a tangentially fired travelling grate boiler. The `gaseous emission characteristics namelyNOXand SO2 were studied, when biomass was co-fired with bituminous coal in 3 proportions of 20%, 40% and 60% by mass. Bagasse, wood chips (Julia flora), sugarcane trash and coconut shell are the biomass fuels co-fired with coal in this study. The air quality status in the vicinity of the plant was assessed when co-firing was done on the basis of the air pollutants namely SPM, SOx, NOx and compared with that when only coal was fired. The ambient air Quality status data obtained from experiments was also validated with SCREEN 3 and ISCST 3 air Modeling software. It was seen that the emission concentrations are higher using SCREEN 3 model, since it predicts the maximum incremental value under the worst case scenario to arrive at most optimum fuel combination. The values obtained from Industrial Source Complex Short Term (ISCST3) modelling software indicates minimum impact if 80/20 combination of biomass/coal is used and these results match well with the experimental results, thus justifying the use of co-firing in sugar mills in India.

Key words: Co-firing, biomass,NO_x, SO₂ andCO₂