Formation of PAH and soot during acetylene pyrolysis at different gas residence times and reaction temperatures

The formation of polycyclic aromatic hydrocarbons (PAH)1 and soot from the pyrolysis of acetylene was studied, taking into account the influence of the operating conditions, such as gas residence time and temperature. The influence of gas residence time was considered between 1.28 and 3.88 s for the experiments carried out under different temperatures from 1073 to 1223 K. The total PAH was calculated as the addition of PAH concentration found in different locations, namely adsorbed on soot and on the reactor walls, and at the outlet gas stream. The relationship between the PAH concentrations and their carcinogenic equivalence sum (KE) 2 was also evaluated. The results obtained showed that temperature and residence time have a high influence on pyrolysis products, especially on the PAH concentration adsorbed on soot, which exhibited the highest KE in all cases studied.

► This study analyses the influence of gas residence time and reaction temperature on PAH and soot formation.
► The present work develops an analytical method for PAH-priorities quantification.
► A major amount of PAH adsorbed on soot is found under every evaluated condition.
► High PAH concentration does not necessarily involve more dangerous effects.