Study On The Emission Characteristic Of Polycyclic Aromatic Hydrocarbons From Coal Pyrolysis

The environment problems caused by coal utilization have been paid widespread attention. It is very necessary to do some research on the formation, emission and control of PAHs during coal utilization,because trace PAHs is widely distributed , is generally difficult to decompose, is harmful with biological accumulation and three-cause tardy effects including carcinogenesis,aberration, mutation.Pyrolysis research, in particular, has gained considerable momentum because of its close connection to combustion,gasification and liquefaction.The results of scientific investigations of coal pyrolysis are the indispensable basis for technology in almost all areas of coal utilization. So the present paper focus on the emission of PAHs from coal pyrolysis.This study was carried out based on the full understanding of the coal pyrolysis process. In order to avoid the error that caused by isolation of particles on filters with subsequent analysis performed, the experiment used flash pyrolysis and Real-time analysis. The pyrolyzer can reach a heating rate as fast as 2×104℃/s and could pyrolyze the same sample at different temperature. PAHs emitted from 16 kinds of different rank Chinese coals during pyrolysis were studied from the internal factors and external factors. The internal factors contains volatile content, carbon content, oxygen content, sulfur content, ash content and maceral. The external factors contain temperature and heating rate. The results show that: the coal type has a remarkable influence on PAHs emission and the high volatile bituminous emit the most PAHs at the same pyrolysis condition. The emission of total PAHs increase with ash content increased. The oxygen and sulfur content has influence on PAHs emission. Maceral components of coal have influence on PAHs emission too, the higher of inertinite content in coal the more PAHs emited. Temperature is an important parameter in coal pyrolysis and with temperatre increased it shows a single peak at 800℃. The PAHs emission decreases with heating rate increasing.