Study On Co-pyrolysis Of Shenfu Coal And Asphalt Shale, Natural Asphalt And Middling Coal Of Coking Coal

Pyrolysis is one of Shenfu coal grading effective utilization technologies. With Extension and Application of low-temperature pyrolysis technology, there appear many key problems, such as how to enhance the quality and increase yields of tar or gas and how to efficiently use Shenfu char. In order to gain breakthrough development for low temperature pyrolysis technology of Shenfu coal, one of the effective methods is to seek some carbonous materials, and cheap high-effective catalysts for co-pyrolysis with Shenfu coal. Therefore, the thesis focus on the co-pyrolysis characteristics of Shenfu coal with asphalt shale, natural asphalt or middling coal of coking coal using aluminium retort method. Effect of the ratio of Shenfu coal and carbonous materials on the yield, composition and structure of co-pyrolysis products was investigated. Furthermore, pyrolysis dynamics of Shenfu coal, asphalt shale, natural asphalt and middling coal of coking coal and co-pyrolysis dynamics of Shenfu coal with asphalt shale, natural asphalt or middling coal of coking coal were established by thermogravimetric analysis, respectively.Co-pyrolysis of Shenfu coal with Qingchuan asphalt shale showed that when pyrolysis terminal temperature was at 520℃and the ratio of Shenfu coal and asphalt shale was equal to 80:20, the tar yield reached 13.7% ,while the tar yield was only 9.2% from pyrolysis of Shenfu coal alone. Compared with the pyrolysis tar of Shenfu coal, the content of aromatic and polarity component decreased and that of aliphatic component increased for co-pyrolysis tar. Gray-King assay coke type of co-pyrolysis char enhanced from A type to C type . After removing minerals of asphalt shale by HCl/HF mixing acids, the conversion ratio increased and tar yield reached 14.4%. The results showed that minerals had negative effect on co-pyrolysis and could promote the decomposition of tar. Thermogravimetric analysis indicated that pyrolysis activation energy of asphalt shale was higher than that of Shenfu coal. Co-pyrolysis activation energy increased with the proportion of asphalt shale, in addition, co-pyrolysis activation energy also increased after removing minerals from asphalt shale.As for co-pyrolysis of Shenfu coal with natural asphalt, under the terminal temperature 520℃, and the ratio of Shenfu coal and asphalt shale at 80:20, the tar yield increased to 14.8%. Compared with the pyrolysis tar of Shenfu coal, the content of aromatic and polarity component reduced, and that of aliphatic component increased for co-pyrolysis tar.Gray-King assay coke type of co-pyrolysis char enhanced from A to C. After removing minerals of natural asphalt by HCl/HF acids, the conversion decreased and tar yield increased as well. So minerals of natural asphalt had certain catalysis on the second decomposition of tar. Thermogravimetric analysis indicated that pyrolysis activation energy of natural asphalt was higher than that of shenfu coal. The activation energy of co-pyrolysis was higher than that of shenfu coal, but lower than that of asphalt shale.Under the terminal temperature 520℃and the ratio of Shenfu coal and middling coal of coking coal at 80:20, the yield of co-pyrolysis tar reduced to 7.9%. Compared with pyrolysis tar of Shenfu coal, the content of aromatic and polarity component increased and that of aliphatic component reduced slightly for co-pyrolysis tar; Gray-King assay coke type of co-pyrolysis char enhanced to C.In conclusion, with co-pyrolysis of Shenfu coal and asphalt shale,the tar yield increased. Gray-King assay coke type was improved for co-pyrolysis of Shenfu coal with asphalt shale ,Natural asphalt and middle coal of coking coal . Co-pyrolysis activation energy of Shenfu coal and other three carboneous matters were higher than that of Shenfu coal during pyrolysis. Activation energy of the four crbonous materials ranked as natural asphalt > asphalt shale >middlings coal >shenfu coal.