Pyrolysis of Biomass

PATRICIA V. LÓPEZ RIVILLI, JORGE DANIEL PEREZ

The 7th Annual ACS Summer School on Sustainability and Green Chemistry

Workshop; The 7th Annual ACS Summer School on Sustainability and Green Chemistry; 2009

ACS American Chemical Society

Se It is already known that use of biomass for different purposes such as energy production is one of the challenges since many years ago. The fact that fossil fuels sources are limited and the environmental pollution caused by combustion or petrochemical uses of these fuels are among the most important reasons for this research. Many efforts were done in this area which is reflected in plants producing bio-oil all around the world and numerous publications and patents in this field [1]. It is well known that bio-oil is an interesting source of several interesting chemicals; nevertheless most of references are directed to renewable energy sources more than experimental conditions appropriate to obtain enriched mixtures useful for their further separation. Fast pyrolysis of wood produces solid char, liquid (bio-oil) and a gaseous fraction. The liquid products have been reported to be of low viscosity and chemically very complex, containing hundreds of different compounds [2]. In an attempt to do a quantification of some of the components present in bio-oil, Branca et. al. selected forty of them from the liquid fraction and carried out GC/MS of samples from different origins. The aim of this study was to establish the correspondence of yields of these compounds with reaction temperature and heating rates conditions. The identified compounds are almost the same than the ones described in the literature [3]. According with reported experimental and theoretical kinetic studies on pyrolysis of several kinds of biomass including reference studies on synthetic biomass; cellulose, hemicelluloses and lignin react independently even in natural samples giving a characteristic pattern of products derived from primary and secondary reactions of intermediates. For instance, phenol derivatives, i.e. phenol, guaiacols, catecols, syringols, vanillins are mainly derived from lignin whereas levoglucosan, furfural and furans are formed from cellulose and hemicelluloses. Therefore we decided to carry out systematic efforts to find pyrolytic conditions appropriate to obtain chemicals from biomass in a practical way. In this report we describe stepwise isothermal fast pyrolysis (SIFP) of pine wood sawdust between 200 and 600°C with nitrogen as carrier gas.