Abstract
The high level of waste tyres in stockpiles has contributed tremendously to environmental pollution and global warming on daily basis. These tyres have also been known to serve as breeding sites for mosquitoes and other disease-causing microbes. Gasification has been identified as one of the alternate pathways that can be used to recover energy from waste tyres. In addition to the gaseous products (syngas), high-value solid products like carbon black, activated carbon and carbon nanotubes can also be obtained from the gasification of waste tyres. This study has evaluated the simultaneous production of syngas and solid carbon (activated carbon) in three different reactor configurations namely; fluidized bed, fixed bed and rotary kiln. A single stage gasification and activation process was employed in the production process by using Aspen Plus® software. This study also evaluated the effects of gasification parameters like the equivalence ratio (ER), the steam-to-fuel ratio (SFR) and the gasifier temperature (GT) on the gasification products from the three reactor configurations. The ER was varied from 0.18 to 0.38, the SFR from 0.1 to 0.25 and the GT from 700 oC to 1000 oC. BET analysis was used in the determination of the surface area of the activated carbon formed at the end of the char activation stage. The optimum conditions for the co-production process in the fluidized bed gasifier occurred at ER of 0.3, SFR of 0.2 and GT of 800 oC. At this condition, the fluidized bed gasifier has a syngas (CO + H2) composition of 50.2%, gas yield of 4.81 Nm3/kg, gas LHV of 6.29 MJ/kg, cold gas efficiency of 84.8%, 89.2 kg (2.02% AC to carbon in feedstock ratio) with BET surface area of 2236 m2/g and carbon conversion ratio of 97.8%...
M.Tech. (Chemical Engineering)