Experimental and theoretical studies on the conversion of biomass pyrolysis tar under the effect of steam

The removal of tar is conducive for improving the energy efficiency of equipment and reducing the damage caused to it. A two-stage continuous feeding apparatus was applied to examine the homogeneous conversion characteristic of biomass pyrolysis tar under the effect of steam. The tar yield could be effectively reduced from 6.68 to 2.30% by increasing steam and feedstock mass ratio (S/F) from 0 to 1.6. Furthermore, given that steam significantly affects phenyl formate (PF) cracking, Gaussian was employed to analyze its reaction mechanism. Rising the temperature from 600 to 1000 °C can improve the pyrolysis rate constant of PF by five to six orders of magnitude, and its primary products are phenol and CO. When PF reacts with H or OH radicals, the most crucial route is these radicals abstract H atom, following by releasing CO from the intermediate products. H radicals can also promote PF craking by combining with C\O atom in oxygen-containing group; among them, H radicals easily bond with the C atom.