Solar Biomass Pyrolysis with Latent Heat Ballast

HUILI ZHANG; JAN BAEYENS; RAF DEWIL; SHUO LI; YIMIN DENG; ANDRÉS REYES URRUTIA; CÉSAR M. VENIER; GERMÁN MAZZA

Xiamen

Conferencia; 5th International Conference on Power and Energy Engineering (ICPEE 2021); 2021

Hong Kong Chemical, Biological & Environmental Engineering Society

The concentratedsolar-driven pyrolysis of biomass (sawdust) was examined in a fluidized bedreactor with 0.15 m I.D. and 0.3 m bed height, using cristobalite sand as bedmaterial. The fluidized bed reactor was fitted with in-bed tubes filled with aphase change material with phase change temperature of 450 to 475 °C. Four, 5and 9 tube-inserts were examined. The solution with 5 tube-insert wasexperimentally demonstrated to considerably influence the bubble sizes andfrequencies in the reactor, leading to an enhanced heat transfer from theirradiated reactor wall to the fluidized bed, and from the fluidized bed to thein-bed tubes. The steam-assisted pyrolysis produced between 40 and 55 wt% of high-qualitybiochar (BET >> 100 m²/g), about 20 to 25 wt% of oxygenated bio-oil, andthe balance as syngas. The operation at moderate temperature and with steaminjection drives the pyrolysis reactor towards biochar production. In using thePCM-ballasted inserts, the temperature could be narrowly controlled within theselected operation range, whereas it was also possible to maintain thetemperature at the required level for 15 to 20 minutes during non-sun periods.CFD simulations of the fluidized bed behavior were performed under OpenFOAM andANSYS-Fluent platforms.