Simulation and optimization of tyre-based steam activated carbons production for gas-phase polycyclic aromatic hydrocarbons abatement

Abstract

In this work, technical solutions for two remarkable environmental problems are undertaken: waste tyres (WT) valorisation by producing steam activated carbons (AC), and gas-phase polycyclic aromatic hydrocarbons (PAH) abatement, by adsorption on those solids. Firstly, the AC production process in a fixed bed reactor was modelled. For this purpose, the random pore model (RPM) was successfully applied, to model the solid evolution throughout the steam activation of WT. The model showed the capability of predicting with a high degree of accuracy both the conversion and the solid properties evolution, depending on the operational variables (i.e. temperature, steam concentration and time). The experimental results obtained in a lab-scale activation system allowed the model validation. Afterwards, the performance of the AC on the cyclic adsorption of naphthalene on gas phase was evaluated and related to the physical properties of the AC. These experiments confirmed the optima AC characteristics for naphthalene abatement. Since the physical properties of the AC can be accurately predicted with the proposed model, the activation process was optimized to enhance the final PAH adsorption capacity of the sorbents. Therefore, in this work, a useful tool for simulation and optimization of the AC production process for the specific application of PAH abatement has been developed.