Analysis of Residual Biomass fast pyrolysis at laboratory scale: experimental and numerical evaluation of spent coffee powders energy content

The thermochemical pyrolysis process is one of the key intermediate processes to flexibly produce electric/thermal power output. In this paper, experimental results of a small externally heated biomass screw reactor are presented. This paper aims at validating a 1D-DAEM model with experimental data collected by varying maximum temperature in fast pyrolysis conditions. The experimental system, here used for the spent coffee conversion, has been specifically designed for allothermic processes, allowing for controlling heating and mass flow rates. A comparison with pellet has been performed to refer the observed yields to literature available data. The implemented four parallel reaction framework coupled with a DAEM model, is able to give results in very good agreement with the bio-oil experimental data yields, showing in any case prediction errors lower than 4.5%. The maximum bio-oil production has been observed at 500 degrees C, both for the pellet and the spent coffee with yields respectively of 66% and 56%.