Profiles and TEQ Concentrations of PAHs Emission From Fluidized Bed Coal Gasification

Abstract

More growing particular attentions are being paid to polycyclic aromatic hydrocarbons (PAHs) generated from coal gasification due to their high mutagenic and carcinogenic. Fluidized bed air and steam gasification of three different rank coals were studied in a bench-scale atmospheric fluidized bed test facility. An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 PAHs specified by US EPA in raw coal, slag, bag house char, cyclone char and fuel gas. The profiles and TEQ concentrations of PAHs emission from fluidized bed coal gasification were discussed. The results indicated that there were mainly three- and four-ringed PAHs in raw coal and fuel gas, but the total PAHs in bag house char and cyclone char were dominated by three-, four- and five-ringed PAHs. The concentrations of three-ringed PAHs in fuel gas were higher than those of four-ringed PAHs, but a reverse phenomenon occurred in bag house char and cyclone char. No PAHs were measured in slag during coal gasification. The total TEQ concentration of five-ringed PAHs mainly dominated in raw coal, fuel gas, bag house char, and cyclone char, and their percentages were about 75–96% by weight. Benzo(a)pyrene (BaP) was the main contributor of TEQ concentration in raw coal and gasified products. In addition, the concentration of PAHs in raw coal increased with the rise of coal rank, and there was not an obvious variation about the concentration of PAHs in gasified products.