Extraction of Liquid Fuel from Pyrolysis of Waste Tyres with Catalyst

Abstract

Bangladesh is a developing and most densely populated country in the world with a total population of about 156.6 million. Her per capita energy consumption is much below the world average. Energy consumption mix is estimated as: indigenous biomass 60%, natural gas 27.45%, oil 11.89%, coal 0.440/0 and hydro 0.23%. More than 770,'o of the countrvs population lives in rural areas and meeting most of their energy needs from traditional biomass fuels. Around 32% have access to electricity, while in rural areas the availability of electricity is only 22%. Only 3-4% of the households have connection of natural gas for cooking. About 2-3% households use kerosene for the same and the rest (over 90%) depend on biomass for their energy needs. Thus, it is crucial to find out alternative and sustainable resources to mitigate the energy crisis. Recent environmental issues and energy security have been emerged as public and political concern which led to alternative way of thinking and renewable energy sources may be an indigenous source of that kind of thinking. As energy demand is becoming acute day by day, scientists are giving efforts on the potentials of utilizing appropriate technologies to recover energy and useful by-products from domestic and industrial solid wastes. Researchers have been conducted for biodegradable and non-biodegradable waste materials. Rubber and plastic containing waste is non-biodegradable. About 20.50 million bicycle/rickshaw tyres become scrap every year and wait for disposal which is about 37% (wt) of total tyre waste production in Bangladesh. It is estimated that 30,750 tons bicycle/rickshaw tyres, 5160 tons motorcycle tyres, and 28,900 tons bus/truck tyres become scrap and are disposed of every year. Disposal of waste tyres causes typical problems for environment. Dumped scrap tyre. in massive stockpiles is one of the possible causes of ideal breeding grounds for disease carrying mosquitoes and other vermin with the aid of rain water deposited in the free space of tyre wall. On the other hand, tyres left in open air may result in significant disturbances and dangerous situations like risk of fire. Different means are available for disposal of waste tyres and one relatively effective way is pyrolysis of there. In the present work, waste bus-tyres were pyrolysed in a fixed bed reactor with catalyst and without catalyst. The objectives were to investigate the composition of derived oil from waste tyre and the effect on oil extraction in presence of catalyst. The influences of VI pyrolysis temperature, catalyst/tyre ratio (CT ratio), heating rate, operating time, sample size etc. oil yield were investigated. The pyrolysis of tyre was carried out within the temperature range of 300°C to 600°C. The optimum pyrolytic oil of 42.0 obtained for tyres pyrolysis and 36.67% (wt) for catalytic pyrolysis at 450°C. A higher temperature and smaller particle size increases the heating rate that resulting a decreased char yield. The cracking of hydrocarbons, resulting increased lI2 content in the gaseous product, is favored by a higher temperature and smaller particle size. The physical properties of the pyrolytic oil were examined. It showed that increase in catalytic temperature and CT ratio resulted in high yield of gas at the expense of oil yield. When CT ratio is increased from 0.13 to 0.30, the yield of gas increased from 13.33% to 15.33 % (wt), and oil yield decreased from 36.67% to 28.0% (wt) at temperature 450°C. High CT ratio favored to increase the concentration of light naphtha in the pyrolytic oil. Fractional distillation of 97% (wt) of the pyrolytic oil from catalytic pyrolysis below 350CC with CT ratio of 0.3 and pyrolysis temperature of 450°C shows that after proper treatment these oil can be used as substitute of alternative fuel or chemical feedstock to Naphtha.