Role of Temperature in the Biomass Steam Pyrolysis in a Conical Spouted Bed Reactor

Abstract

The steam pyrolysis of pinewood sawdust has been conducted in a bench scale plant provided with a conical spouted bed reactor (CSBR). This process is of uttermost relevance for the in-line valorisation of pyrolysis volatiles, specifically for their catalytic steam reforming for hydrogen production. The influence temperature in the 500-800 oC range has on the product yields has been analysed. A detailed analysis of the gaseous streamhas been carried out by chromatographic techniques, and the char samples have been characterized by several techniques.A high bio-oil yield was obtained at 500 oC (75.4 wt.%), which is evidence of the suitable features of the CSBR for this process. As temperature was increased, higher gas and lower liquid and char yields were obtained. Steam was fully inert at low pyrolysis temperatures (500-600oC), and only had a little influence at 700oC due to the low gas residence time in the CSBR. At 800 oC, the reaction mechanism was controlled by gasification reactions.The composition of the liquid fraction was considerably influenced by pyrolysis temperature, with a less oxygenated stream as temperature was increased. The char obtained in the whole temperature range can be further used as active carbon or energy source.