Upgrading of refuse derived fuel through torrefaction and carbonization: Evaluation of RDF char fuel properties

Refuse derived fuel (RDF) is produced in large amounts but its heterogeneous nature and low calorific value reduce the potential for energetic valorization of this material. In this work, the torrefaction and carbonization of RDF was studied in a temperature range of 200-400 degrees C and residence times from 15 to 60 min, yielding chars with increased density, high heating value (HHV), carbon content, ash content and fixed carbon. Leaching experiments showed that some inorganic components like calcium or chlorine could be removed from the RDF char, upgrading its fuel quality. For temperatures in the torrefaction range (200 degrees C and 250 degrees C), energy yields were higher than 96.3% and process energy efficiencies were higher than 85%, but the HHV of the RDF chars were lower than 19.4 MJ kg(-1). In the carbonization range (300 degrees C to 400 degrees C) it was possible to obtain RDF chars with HHV in the range of 20.1-26.2 MJ kg(-1), with energy yields from 84.5 to 91.7% and process energy efficiencies from 70.8 to 79.2%. The obtained results showed that thermochemical processing can be used to upgrade RDF thus promoting sustainable solutions for its management and valorization. (C) 2019 Elsevier Ltd. All rights reserved.