CMA

27 of the Cement Sustainability Initiative (CSI), in which the largest worldwide cement companies are actively involved under the umbrella of the World Business Council for Sustainable Development. REVIEW OF ALTERNATIVE FUELS, MARKETS Although a variety of technical constraints limit the use of alternative fuels in cement plants, the range of wastes that potentially can be used in the cement sector is very broad. In addition to any processing limitations, the cement sector has developed international guidelines listing waste that is prohibited for use as alternative fuel, including radioactive waste, infectious waste, and explosives. The waste used by cement plants as alternative fuel can be classified into five broad categories, which generally are associated with specific regulations and/ or implementation constraints related to the materials • Municipal waste • Biomass • Non-hazardous industrial and commercial waste • Other unclassified alternative fuels. Both research and international experience suggest that no single alternative fuel can, by itself, meet the entire thermal demand of cement manufacturing. However, a mix of different alternative fuels can achieve that goal. AVAILABLE HAZARDOUS WASTE WHICH CAN BE USED AS PARTIAL FUEL IN CEMENT KILN • Organic residue from Pharmaceuticals and Pesticide industry • Spent solvent • Sludge from petrochemical / oil refinery • Slaughter House Waste • Waste Oil • Paint sludge • Effluent Treatment Plant Sludge • Spent Pot Lining from Aluminum Industry • Spent Carbon AFR’s can reduce input costs, but they can also adversely affect process stability and product performance due to their variable composition and undesirable levels of moisture, inert ballast and volatiles. Alternative fuels can also be difficult to ignite and usually need to be burned at higher oxygen levels to make sure calorific value variations do not cause intermittent reducing conditions in the kiln. These and other AFR material properties can work against stable kiln operation and when AFRs are used in large quantities some loss in capacity and product quality variation can usually be expected. Alternative fuels which can be used to increase thermal substitution rate (TSR) in cement industry (use of CV of waste as fuel in cement kiln) S No Fuel Calorific Value (kcal/kg) 1 RDF from Municipal Solid waste 2800-3800 2 Used Tires 6700-7700 3 Hazardous Waste 4000-9500 4 Industrial Plastic Waste 4070-6620 5 Biomass 2500-3800 6 Slaughter House Waste 700-1400 7 Poultry Litter 2700-3800 8 Dried Sewage Sludge 1700-1900 Source : Holtech & CPCB Alternative Raw Materials which can be used as blending material S No Alternative Raw material Available Quantity in million tonnes per annum 1 Fly Ash (cement blending material) 200.0 2 Blast Furnace Slag from Steel Industry 10.0 3 Lime Sludge (Paper, Carbide, Sugar Industry Sludge) 4.5 4 Red Mud from Aluminum Industry 3.75 5 Foundry Sludge / Sand - 6 Chrome Sludge as mineralizer - 7 Lead Zinc Slag 0.5 8 Phosphate Chalk - Source : Holtech Cement kilns have a number of characteristics which make them ideal installations for disposal of wastes through co processing route in an environmentally sound manner.