An experimental investigation into the formation of polycyclic-aromatic hydrocarbons (PAH) from pyrolysis of biomass materials

The formation of polycyclic-aromatic hydrocarbons (PAH) from the pyrolysis of cellulose, pectin, and chlorogenic acid was studied. The primary product, mostly primary volatile tar, was exposed to a higher thermal severity, i.e. high temperatures and long residence times. The reactor setup consisted of a quartz tube with two zones, zone I and II, each heated and controlled separately. Zone I was used to first pyrolyze the substrate at 300 degreesC to produce a low temperature tar (LTT) as well as to pyrolyze the product char at 600 degreesC to produce a high temperature tar (HTT). The LTT and HTT were then subjected to a high thermal severity in the second zone (zone II) where the temperature was varied between 700 and 850 degreesC. The residence time of the volatiles in zone II was varied between ca. 90 and 1400 ms (calculated at 800 degreesC). The results showed that the yield of most PAHs increased with temperature, except in a few cases where the yield of two- and three-ring PAHs exhibited a maximum. PAHs yields also generally increased as the residence time was increased from 90 to 1400 ms at 800 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.