Catalytic effect of ZSM-5 zeolite and HY-340 niobic acid on the pyrolysis of industrial kraft lignins

Abstract Catalytic pyrolysis studies of industrial Kraft lignins were performed using two acid catalysts: a widely known commercial zeolite (ZSM-5) and a relatively unexplored acid catalyst (HY-340) which has desirable properties, besides having a low cost compared to traditional pyrolysis catalysts. Vapor composition data were determined by a micropyrolyzer coupled to a gas chromatograph and a mass spectrometer (Py-GC/MS). The effects of operational parameters such as pyrolysis temperature and concentration of the catalyst added to the two lignins were also investigated. In addition, for a better understanding of the thermal decomposition kinetics of the studied biomasses, thermogravimetric analyses were also carried out at different heating rates. The results obtained showed that the use of ZSM-5 as a catalyst in the pyrolysis reaction of both lignins promotes the formation of aromatic hydrocarbons. This increase in the selectivity for hydrocarbons reached a maximum area of 91% for lignin 1 and 89% for lignin 2. Whereas the use of HY-340 resulted in an increase in the selectivity for hydrocarbons, mainly alkanes, which reached a maximum area of 92% for lignin 1 and 82% for lignin 2.