Efeito catalítico de zeólita ZSM-5 e ácido nióbico HY-340 na pirólise e hidropirólise de ligninas kraft industriais.

Abstract

The continued dependence of petroleum for the production of energy and various materials has increased every day. Biomass is a renewable energy source that could partially replace fossil sources for the production of chemicals and energy. Large amounts of lignin are produced in the pulp and paper industry and are not used in a more valuable way. Lignin has a great potential as a renewable raw material for energy and high value chemicals. This work aimed to study the analytical pyrolysis and hydropyrolysis process of industrial Kraft lignins evaluating the influence of the operating temperature and the addition of two acid catalysts: a commercially known zeolite (ZSM-5) and a relatively acidic catalyst (HY-340) which has desirable properties, and has 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 and hydropyrolysis reactions of both lignins promotes the formation of aromatic hydrocarbons. In analytical pyrolysis this increase in the selectivity for hydrocarbons reached a maximum of 91% of area for lignin 1 and 89% for lignin 2, whereas in the hydropyrolysis the selectivity reached a maximum area of 98% area for lignin 1 and 99% for lignin 2. The addition of HY-340 in the pyrolysis and hydropyolysis reactions resulted in an increase in the selectivity of hydrocarbons, mainly alkanes, which reached a maximum of 92% of area for lignin 1 and 82% for lignin 2, whereas in hydropyrolysis the selectivity reached a maximum of 93% area for lignin 1 and 92% for lignin 2.