Influence of Mg and Co addition on Fe based catalyst for in-situ biomass pyrolysis

Abstract

In this work, the effect of Mg and Co on Fe based catalyst for biomass in-situ pyrolysis was investigated in a fixed-bed reactor. The yields of hydrogen and light aromatics could be improved with Fe-Mg/Co catalyst. The maximum H2 yield of 113.48 mL/g was obtained with the 15Fe0.8Mg catalyst at 700 ℃. Fe-Mg/Co not only promoted cracking and restructuring of bio-oil but also enhanced the thermal decomposition of the heavier bio-oil at the higher temperature, which resulted in the improvement of BTX (benzene, toluene, xylene), PCN (phenol, cresol, naphthalene) yields. The best conditions for the formation of BTX, PC and naphthalene are 15Fe0.8Mg0.7Co at 700 ℃. The surface characteristics of Fe-Mg/Co catalyst were analyzed with TEM, XRD and H2-TPR, SEM, Raman, FT-IR, XPS. TEM result showed that the size of particle changed from 16.23 to 6.73 and 6.43 nm by adding the Mg and Mg-Co, respectively. Meanwhile, XRD and XPS results indicated that Fe2O3 was transformed into Fe. Comparing the spherical particles in the SEM, change in particle size can be clearly observed, 15Fe> 15Fe0.8Mg> 15Fe0.8Mg0.7Co. Mg and Co promoted Fe catalyst activity to form highly active sites and then further promoted the steam reforming reaction.