With the phenomenal increase in number of automobiles in India during recent years the demand of tyres as original equipment and as replacement has also increased. As every new tyre produced is destined to go to waste stream for disposal or recycling or reclamation, despite its passage through retreading process, the number of used tyres being discarded is going to increase significantly. Timely action regarding recycling of used tyres is necessary in view to solve the problem of disposal of used tyres keeping in view the increasing cost of raw material, resource constraints and environmental problems including fire and health hazards associated with the stockpiles of the used tyres. The world generates about 1.5 billion waste tyres annually, 40 percent of them in emerging markets such as China, India, South America, Southeast Asia, South Africa and Eastern Europe. In India, all new vehicles have radial tyres, so now there are piles of radial tyres here. Analysis indicates that 0.6 Million Tons of tyres scrap is generated in the country annually. It is commonly accepted in the tyre industry that about one tyre per person per year is discarded. Since there is no industry group or governmental agency that monitors tyre disposal in the country, the best estimates that can be made are based on tyre production. So supply situation of scrap tyres is only going to improve in years to come as a result of growing vehicle population in India. Mandatory scrapping of all ELV (End of Life Vehicles), in metros by 2010-11 and across India by 2012-13 is also likely to ensure large scale availability of scrap tyres at select locations there by encouraging organized players. The management of scrap tyres has become a growing problem in recent years. Scrap tyres represent one of several special wastes that are difficult for municipalities to handle. Whole tyres are difficult to landfill because they tend to float to the surface. These stockpiles are also direct loss of energy and resources in addition to fire & health hazard and other environmental issues. The main constituent of a tyre is rubber and the largest single application of rubber is vehicle tyres. Also the requirement of tyre is directly related to growth of automobile. The production of automobiles is forecast to continue to rise and is indicative of buoyant economic conditions for tyre industry, but at the same time guarantee and annual discarded scrap tyre volume growing at the same rate as new tyre manufacture. Waste represents a threat to the environment and human health if not handled or disposed of properly. According to this hierarchy, the priority of any country should be to extract the maximum practical benefits from products and prevent and minimize the waste that is generated. Thus, strategies for waste disposal should focus on waste prevention and minimization through the ‘3 Rs’ - Reduce, Reuse and Recycle. Gasification/Pyrolysis are two related forms of thermal treatment where Waste materials are heated to high temperatures with limited oxygen availability. Tyre to Energy Alternatives Tyres have a fuel value of 12,000 to 16,000 Btu per pound, slightly higher than that of coal. With existing technology, tyre combustion can meet environmental requirements. Combustion facilities currently using tyres as fuel include: Power plants, Tyre manufacturing plants, Cement kilns, Pulp and paper plants & Small package steam generators etc. Waste Tyre Pyrolysis: Pyrolysis of tyres involves the application of heat to produce chemical changes and derive various products such as carbon black, fuel oil, steel wires and combustible gases. The history of tyre pyrolysis projects to date indicates that the problems blocking them have been technical and economic. These include the problems of upgrading the carbon black by-product while keeping down the operating cost of the process and the capital cost of the plant. Recently, there has been a technical advance in char upgrading which have helped tyre pyrolysis economically feasible. Given below is the Input to Output ratio: Input Material: Waste Tyre Input : 1000 Kgs Output - 450 lit of Industrial Fuel oil - 125 Kg of Petroleum Gas - 330 Kg of Carbon Black - Up to 110 Kg of Steel wires Output is fuel oil which is mixture of petrol, diesel and kerosene. This Fuel oil can be directly used in boilers, generators, thermic fluid heaters, hot air generators, hot water generators, Furnace etc. Economics A preliminary cost analysis for a proposed tyre reprocessing unit is done on the following formula which is used to evaluate process economics. The process is highly profitable even for a small to larger unit capacity. The following formula is used to evaluate the process economics: P=F+R-C-T-S-D Where P is the profit, F is the tipping fee collected for tyre disposal, R is the revenue received from the sale of products, C is the processing cost of transportation of tyres, S is the cost of tyre cutting or shredding, and D is the cost of disposal of waste products. A small unit for tyre pyrolysis can cost from Rs 3.5 Crores to Rs 4.0 Crores depending on the capacity of the unit. This capital cost of investment will increase as the capacity of the unit increases. Conclusion Tyres should be utilized to minimize environmental impact and maximize conservation of natural resources. The management of scrap tyres has become a growing problem in recent years. But the pyrolysis technology has a great potential for using a major portion of scrap tyres generated each year, and actually reducing the tyre stockpiles that is in other words to convert waste stream of tyres into marketable products. Waste tyre pyrolysis has indeed identified existing and potential source reduction and utilization methods which will be effective in solving the tyre problem in the coming years.
