RECOVERING OF LIQUID FUEL FROM THE SMOLDERING COMBUSTION OF OLD TIRES

摘要

The disposal of products at the end of their life remains a challenging problem. It is particularly the case for used tires, most of them being not reusable. A promising alternative to conventional incineration is one in which the solid material smolders, producing exhaust gases containing combustible vapors which are then condensed. In this work, an experimental study on the forward combustion of a bed of shredded tires is presented. It offers an interesting potential: assure the transformation into a usable fuel and energy while meeting standards on toxic emissions. After ignition, a self-sustained smoldering combustion reaction front is allowed to propagate through porous media consisting of pieces of tires and refractory briquettes. The experimental apparatus consists of the smoldering reactor, a fan, a collection bucket, and an afterburner and post-combustion chamber to ensure the destruction of all toxic emissions. The results show that air flow and tire concentration define different modes of combustion. The smolder reaction generates the potential recovery of pyrolysis products. As the reaction front propagates, cooling of these products result in the collection of condensed hydrocarbons. This is an important part of the process because it allows recovering of significantfraction of the tires (till 35% in mass). The heat of combustion of this oil is of the order 40-43 kJ/kg; thus it could be potentially used as fuel. Its chemical composition is also determined. This study evidences a promising methodology to convert discarded tires into usable fuel, while significantly reducing the mass of residue.