The effect of the oxygen fraction on volatile organic compound emissions from waste combustion

Abstract

Volatile organic compound (VOC) emissions from the combustion of household refuse were investigated in a 20 kW experimental boiler with a stationary grate. Swedish household refuse from kitchens was manually fed into the combustion chamber. The oxygen fraction ranged from 0.068 to 0.136 on dry basis. The gas temperature in the chamber center ranged from 860 to 980 K. The measurements made included volatile organic compounds (VOCs), carbon monoxide and carbon dioxide. The identification and analysis of organic pollutants were performed by thermal desorption Gas Chromatography and Mass Spectrometry (GC/MS) with a Tenax sampling train. The major organic emissions identified were toluene and various benzenes. Total volatile organic compound (TVOC) emissions were between 2.85 and 8.31 mg/Nm3. The concentration of toluene was up to 93.82 μg/Nm3, which corresponded to the lowest oxygen fraction, 0.068, and highest carbon monoxide emission, 606 mg/Nm3 on average. In general, the emissions of organic pollutants increase with the decrease in oxygen fraction. This may have been due to oxygen deficiency which results in incomplete combustion. For naphthalene and phenol, the concentration were very low, in a range between 0.12 and 0.60 μg/Nm3. The emission pattern was not so clear and more data are needed.