Hydrogen and methane production within the concept of "waste-to- energy": An innovative approach to metal recycling from mill scale

In this study, it was aimed to provide a new approach to the concept of waste-to-energy by obtaining gaseous products rich in hydrogen and methane by pyrolysis of end-of-life tire (ELT), plastic and paper industry process wastes, and to reduce the mill scale formed in high amounts as a result of the production activities of this gas product in the iron and steel industry. In order to recycle metallic iron from waste (iron oxide layer), its evaluation as an alternative has been investigated. Within the scope of the study, two reactor types, horizontal and vertical flow, were studied, the energy content of the gas products formed was calculated and scale reduction studies were carried out. H2 and CH4 gases have high efficiency in reduction reactions, and the total H2 (%44) and CH4 (%20) contents of the gas products obtained in the pyrolysis step carried out in the horizontal flow reactor were determined as maximum 64% and the calorific value was calculated as maximum 4079 kcal/m3. It has been determined that the horizontal flow reactor provides more efficient results compared to the vertical flow reactor. As a result of the research, the complete recycling of mill scale into metallic iron was achieved with the horizontal flow reactor.