Itsaso Barbarias

Hydrogen production from biomass by continuous fast pyrolysis and in-line steam reforming

The continuous fast pyrolysis (500 °C) of pine wood sawdust has been studied in a conical spouted bed reactor (CSBR) followed by in-line steam reforming of the pyrolysis vapours in a fluidised bed reactor on a Ni commercial catalyst. An analysis has been carried out on the effect reforming temperature in the 550–700 °C range, space time from 2.5 to 30 gcat min gvolatiles−1 and steam/biomass ratio between 2 and 5 have on the pyrolysis volatile conversion, H2 yield and gaseous stream composition. The continuous pyrolysis-reforming process has shown great potential for H2 production from biomass, with no operational problems and allowing for full conversion of pyrolysis vapours. Thus, a maximum H2 yield of 117 g per kg of biomass was obtained at 600 °C, at the highest space time studied (30 gcat min gvolatiles−1) and for a S/B ratio of 4. This yield is higher than those obtained by other alternatives, such as direct steam gasification or bio-oil reforming. Moreover, the char produced in the pyrolysis step has been continuously removed from the conical spouted bed reactor in order to be upgraded following promising valorisation alternatives.

Styrene recovery from polystyrene by flash pyrolysis in a conical spouted bed reactor.

Continuous pyrolysis of polystyrene has been studied in a conical spouted bed reactor with the main aim of enhancing styrene monomer recovery. Thermal degradation in a thermogravimetric analyser was conducted as a preliminary study in order to apply this information in the pyrolysis in the conical spouted bed reactor. The effects of temperature and gas flow rate in the conical spouted bed reactor on product yield and composition have been determined in the 450-600°C range by using a spouting velocity from 1.25 to 3.5 times the minimum one. Styrene yield is strongly influenced by both temperature and gas flow rate, with the maximum yield being 70.6 wt% at 500°C and a gas velocity twice the minimum one.