Coal tar, also known as tar, is produced by the pyrolysis of coal and is one of the by-products of the coking industry. Its output is about 3%-4% of the amount of coal produced by the furnace. At normal temperature, coal tar exists as a black liquid, and the density is usually between 0.95-1.10 g/cm3. Coal tar is mainly composed of polycyclic aromatic compounds, with more than 20,000 species, of which 13 kinds account for more than 1%, are: 1-methylnaphthalene, 2-methylnaphthalene, acenaphthene, fluorene Oxyfluorene, anthracene, phenanthrene, carbazole, fluoranthene, quinoline, pyrene, cresol, naphthalene. At present, there are more than 500 single compounds separated and identified from coal tar, but simple separation and extraction have little effect on improving the economic benefits of coal tar. The domestic and international optimism is the application of its deep-processed refined products. This is also the current trend of investment and technological research and development in the coal chemical industry.
