Fluidized-bed gasification of waste tire powders

A laboratory-scale fluidized-bed gasifier was used to investigate the characteristics of tire powder gasification. Granulated tire powders were gasified with air at a temperature range of 350–900 °C. Results showed that the operational parameters [i.e., equivalence ratio (ER) and tire feed rate] and tire particle size have significant effects on various gasification results, including the bed temperature, secondary reaction temperature, product gas composition, gas yield, gas heating value, product (i.e., gas, tar, and char) distribution, volatile release ratio, fixed carbon conversion ratio, and energy recovery ratio. An optimum ER may exist for a fixed tire feed rate and tire particle size at which higher product gas yield, gas heating value, and energy recovery ratio can be achieved. A gaseous product, mainly containing CO, H2, CH4, C2H6, and longer-chain hydrocarbon with a calorific value of about 6 MJ/Nm3, can be generated at the highest yield rate of 11 Nm3/h under the optimum operation conditions achieved in this study. The char and oil yields were found to lie in the range of 24–37% and 0–37%, respectively, corresponding to over 90% and 18% of the volatile release and fixed carbon conversion. Under these conditions, the energy recovery was between 15% and 38%.