Fractional condensation of pyrolysis oil from fast pyrolysis of food waste digestate for enrichment of high value-added nitrogen-containing components

Abstract

Fast pyrolysis over CaO coupled with fractional condensation was proposed to facilitate the efficient utilization of food waste digestate (FD) and upgrading py-oil. The three-stage fractional condensation temperature was optimized and the effect of CaO catalytic pyrolysis as well as the fractional condensation behavior for enrichment of high value-added nitrogen-containing components (NCCs) were evaluated. The results indicated that fractional condensation temperature was set to 0 °C, 60 °C and 120 °C, which were suitable for enriching NCCs, water and phenols, respectively. In addition, the application of CaO inhibited the production of water during the pyrolysis process of FD and increased the lower heating values of py-oil. Fast pyrolysis over CaO coupled with fractional condensation decreased the content of oxygen-containing compounds (OCCs) and promoted the enrichment of NCCs (71.14 %) in the low-temperature condensation stage, especially the pyrroles (29.03 %). In addition, the formation path of pyrroles and the effect of CaO on the process evolution were proposed.