Properties of Biochars Obtained from RDF by Carbonization: Influences of Devolatilization Severity

This paper criticizes the effectiveness of carbonization as a thermal method to upgrade the fuel properties of refuse derived fuel (RDF). For this purpose, RDF was subjected to carbonization at temperatures between 400 and 900 °C to monitor the changes in organic and inorganic portions of RDF, and its burning characteristics. The obtained biochars were characterized by proximate and ultimate analyses, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and thermal analysis (TG, DSC) methods. It can be concluded that carbonization is able to improve the calorific value of RDF only when this process is applied at 400 °C since serious losses took place in organic part at higher temperatures and increase in the ash yield overtook the improvement in the fixed carbon content. Besides, carbonization led to important reductions in the burning reactivity and the obtained biochars showed more reasonable burning characteristics in comparison to untreated RDF.