Study on the influence of residence time on the componential evolution of biomass pyrolysis vapors during indirect heat exchange process through a combining method of bio-oil composition inversion and function fitting

Abstract

A novel and effective experimental method for describing the evolution curves and hot maps of biomass pyrolysis vapors with the adjustment of sweeping gas flow rate was developed during condensation. The composition proportion of pyrolysis vapors was inverted from the composition quantification of segmental bio-oil recovered by the specific condenser with two flumes. The mathematical relationship between location and vapor composition was fitted by Slogistic function. The condensable proportion of water decreased from 85% to 60% as N2 flow rate increased from 100 mL/min to 500 mL/min under 340 K water bath. But 500 mL/min N2 flow rate accelerated the disturbance of condensing field and improved the recoveries of components with stronger condensing abilities than water. The condensable proportion of guaiacol and its derivatives decreased from 60% to 40% under 300 mL/min but increased to 55% under 500 mL/min. Furthermore, the evolution difference between high-proportion and low-proportion components in pyrolysis vapors in the condensing field was also discussed as well as the unique evolution of components with azeotrope phenomenon or special solubility. For the first time, the adjustment mechanism of constant non-condensable components on the evolution of condensable components was clarified during water bath condensation, which would remarkably improve the comprehension for the complex phase transition process during the selective condensation of biomass pyrolysis vapors.

Keywords

• Biomass pyrolysis
• Selective condensation
• Vapor evolution
• Non-condensable gasses
• Function fitting