Use of a reforming catalyst for hydrogen production in the carbonization process of torrefied biomass

The utilization of charcoal from woody biomass is an efficient way to reduce CO₂ emissions from the metallurgical industry. The main aim of this work is to study the charcoal production process from torrefied biomass. For this purpose, torrefaction (3^◦C min⁻¹, 250^◦C, 30 min) and carbonization (3^◦C min⁻¹, 750^◦C, 30 min) experiments of eucalyptus wood were carried out in a 3.5 L tank reactor. In the carbonization experiments, a thermo-catalytic treatment of the vaporized phase was also performed, with the objective of producing less condensates and H₂-rich gases. The results show that the torrefaction pre-treatment does not affect the chemical properties of charcoal but significantly improves the performance of the carbonization process, where more than 50 wt% of charcoal is obtained. In addition, the thermal and thermo-catalytic treatment of the vaporized phase during the carbonization of torrefied biomass yields better results than in the case of fresh biomass. When torrefied biomass is used as raw material and the reforming catalyst is employed to treat the vapors and gases, a proportion of 71 vol% of H₂ in the gases is achieved, together with very low quantities of condensates (8.0 wt%). This allows designing a carbonization process in which, in addition to charcoal, pure H₂ can also be produced.