Study On Extraction Phenols Of The Medium And Low Temperature Coal Tar From North Shaanxi

The medium and low temperature coal tar is one of the by-products of the processing to produce semicoke and gas from carbonization of coal. It includes many kinds of complex compounds especially phenols. The phenols are hazardous substances as they can increase the carbon residual, foul smell, discoloration, corrosion, bad combustion conditions and other negative effects for fuel oil from medium and low temperature coal tar, but it is valuable to be as chemical raw materials if we extract it from the medium and low temperature coal tar. As raw material, phenols can produce many kinds of products such as plastics, adhesives, pesticides, disinfectants, surfactants, tanning agents and so on, as well as to improve the quality of fuel products. With the rapid development of industry, the demand of the phenols also increased significantly. Therefore, extraction of phenols from medium and low temperature coal tar is an effective way of comprehensive utilization for coal tar.The city Yulin in north Shaanxi Province produces thousands of tons of medium and low temperature coal tar per day. However, due to a lack of knowledge on the use of low temperature coal tar and the bad color and odor, the people there only pay more attention on selling coal, coke and semicoke, which creates enormous waste to the resources.The typical medium and low temperature coal-tar samples(light and heavy tar) was taken form Fugu as the objects of study, the acid-alkali decomposition method to extract phenols was researched in this article. We determinated the basic nature of the heavy tar and light tar such as density, viscosity, moisture, ash, toluene insoluble and elemental analysis, and distill them into four fractions:before 210℃,210℃-230℃,230℃-270℃and 270℃-300℃.We also determined the phenol content, minimum soda-oil ratio, minimum water-oil ratio and the best process condition (including soda-wash and acid wash conditions) through orthogonal experiments of the four fractions, Thus it provides the reference for the phenols extraction processing for medium and low temperature coal tar. At last we used GC-MS analyse method to detect the crude phenols which was extracted from distill partitions by benzene, from the detection results we know that the lower-grade phenols in coal tar is much more than the higher-grade phenols. Therefore, it will be largely increased the economic, environmental and social benefits of coal tar to extract the lower-grade phenols from the medium and low temperature coal-tar.