Catalytic conversion characteristics of tar at different temperatures during circulating fluidized bed gasification

Char catalytic conversion of tar at different temperatures was carried out on a laboratory-scale circulating fluidized bed to providing theoretical support for the removal of tar. Various modern detection techniques were used to analyze the gas, tar and char, such as the gas chromatograph, the specific surface area analyzer and the gas chromatograph mass spectroscopy (GC-MS). The efficiency of tar conversion (ETC) could be effectively improved by the increasing temperature, while transformation characteristics of the organic compounds of the used tar also changed. When the temperature increased from 850 °C to 900 °C, the catalytic capability of char was improved, resulting a reducing of the heavy polycyclic aromatic hydrocarbon compounds (heavy PAH compounds) of the produced tar. When the temperature increased from 900 °C to 950 °C, the catalytic capability of char weakened, so the heavy PAH compounds increased, caused by the intensifying of tar thermal cracking. At the tested temperature (850–950 °C), the conversion of naphthalene, the most abundant organic compound in the used tar, has not been seem a significant change, showing a selectivity of the char catalyst. •The tests were carried out in a CFB gasifier during char gasification.•The real tar was introduced into the circulating fluidized bed gasifier by pre-mixing of the tar and char.•The effect of temperature on the different components reforming of the tar was investigated.