Recycling And Optimization Of Waste Tyre Using Pyrolysis:- Nwahiri, Kingsley N

ABSTRACT ix The potential ofwaste conversion to energy can be exploited to relieve the burden ofenergy supply from fossil fuels and ease environmental problems. Therefore, the pyrolysis of waste tire is an exciting technique of converting waste materials into useful products by thermal decomposition at elevated temperature under inert conditions. This research study presents a simulation flowsheet model of a waste tire pyrolysis process with feed capacity of 150 kg/h. Aspen HYSYS VI0 was used to develop a computational steady-state model to simulate the pyrolysis of waste tire and analyze its performance. The Peng-Robinson fluid package was used for the simulation. The pyrolysis reaction was modeled by a combination ofthe yield-shift reactor and the Gibbs reactor. The conversion of hypothetical raw materials (waste tire) to conventional components is done in the yield shift reactor. The Gibbs reactor then calculates the chemical and phase equilibria, predicting the composition of the end product (by minimization of Gibbs free energy). The simulation model was analyzed by varying the process temperature from 400 - 800 °C. At a pyrolysis temperature of 650 °C and atmospheric pressure, 82% liquid oil yield was obtained. The product composition and chemical properties of the pyrolysis oil were also predicted by the simulation and are in good agreement with experimental results. The simulation findings clearly show that the heavy hydrocarbon chains C7-C14 increase at higher temperatures; this is attributed to the extensive cracking ofthe larger hydrocarbon chains at higher temperatures. This has proved that pyrolysis of Waste tire can give a very good yield of liquid product and is a viable recycling technique. This simulation model can thus serve as a robust tool to respond to market conditions that dictate fuel demand and prices while at the same time identifying optimum process conditions (e.g. temperature) driven by process economics.