Combustion properties and toxicity analysis of coal gasification tar residue

Coal gasification tar residue (CGTR) is a kind of solid waste from coal gasification, especially in fixed-bed technology. With high fixed carbon and caloric value, it can be used as an organic feedstock and/or fuel. The combustion properties of CGTR before and after extracted by ethyl acetate were investigated. The toxicity of extract and emissions during combustion was analyzed by gas chromatography (GC) and gas chromatography and mass spectrometer (GC-MS). Experiments show that CGTR can volatilize toxic matter such as alkyl-substituted phenols, amides, and polycyclic aromatic hydrocarbons (PAHs), etc., during pyrolysis at temperature below 400 °C. After CGTR was extracted with ethyl acetate, the separated solid residues were more stable and environmentally friendly than CGTR if used as fuel. Very few toxic emissions are from the residue extracted from CGTR at temperature below 400 °C. Much heat can release when the extracted residue combusts from 400 °C to 700 °C.