Visual liquefaction process of biomass pyrolysis vapors during indirect heat exchange: Experimental description, prediction, and verification

The present investigation proposed an experimental method combining bio-oil segmental recovery, vapor composition inversion, and function fitting, to describe the vapor evolution curves and heat maps of water, acetic acid, furfural, phenol, MCP, guaiacol and its derivatives in the indirect condensing field regulated by continuous water bath temperatures within 280–364 K. Under 280 K water bath, the recovery proportion of water exceeded 50 % after pyrolysis vapors moved 8 cm from inlet, and soon surpassed 90 % after 12.5 cm. At 337 K, 50 % recovery proportion of water required the vapors to move 20 cm, while guaiacol required only 10 cm for the same proportion. Half of the evolution description data were sampled and utilized to fit the prediction curves of vapor evolution with increasing bath temperature, and another half were used to verify these prediction curves. The overall prediction accuracy of the representative components remained at 70 %, despite the local accuracies less than 50 % within 280–300 K and 355–364 K. These findings provided a visual description and prediction method for the selective condensation of pyrolysis vapors. The cycle from research to application of selective condensation was effectively shortened by the prediction of vapor evolution under water bath based on sampling experiments.