Reactivity of brazilian coal, charcoal, imported coal and blends aiming to their injection into blast furnaces

For about 10 years the steel industry in Brazil has used pulverized coal injection (PCI) technology in the blast furnaces based on imported coals. In order to decrease the dependence on imported coals, Brazilian coal, which has limited use due to high ash content, was suggested to be mixed with imported coal and charcoal. The aim was to examine the reactivity of the samples. The charcoal use in the steel industry contributes to the CO2 emission reduction, since it represents a renewable source of energy. The reactivity of the coals, charcoal and mixtures was evaluated through simultaneous thermal analyses. Results of this study are presented and discussed

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 °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 °C and 250 °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 °C to 400 °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.This work was supported by the CITRI, S.A. project I&DT nº 24878; and by the Portuguese Foundation for Science and Technology (grant no. SFRH/BD/111956/2015), co-financed by the Operational Program Human Potential and the European Social Fund-European Union