Pyrolysis Characteristics of Lignite in a Fluidized Bed: Influence of Pyrolysis Temperature

Coal pyrolysis to produce liquid fuel is one of promising way to convert coal. The fast pyrolysis of lignite at different temperatures (450°C, 500°C, 550°C, 600°C, 650°C) in a fluidized bed reactor was studied in this paper. The yield of tar, gas, and semi-coke was investigated at different pyrolysis temperatures. At the same time, the gas and liquid products were analyzed by GC-TCD and gas chromatography-mass spectrometry (GC-MS). The results showed that pyrolysis temperature has a great influence on the tar, gas and char yield. There is a maximum tar yield at temperature 600°C, while the gas yield has the same trend with temperature. However, semi-coke has the opposite trend with increasing temperature. Pyrolysis tar contains a large number of chemical substances which are very good chemical raw materials. Phenols content is the highest in coal tar. The composition of coal tar is also strongly influenced by temperature.