The influence of maceral composition on Rock-Eval Pyrolysis

• Main Authors: Pin —Ju Su, 蘇品如
• Other Authors: Louis L. Tsai
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/55847167699041388701

碩士 === 國立中央大學 === 應用地質研究所 === 89 === ABSTRACT In order to understand better the properties of coal, macerals were separated by density liquid due to their difference in specific gravity. The purpose of this research is to know the properties of macerals in Rock-Eval pyrolysis. This study started from examining the influence of density liquid in pyrolysis, so as to choose the most suitable liquid for separation. Three chemical compounds, zinc bromide, zinc chloride, and potassium iodide, were chosen as density liquids. Coal samples were soaked in different density liquid, then washed and dried for pyrolysis. It revealed that pyrolytic parameters could be resumed back to their original values after washing. Furthermore, chemical compounds with low melting point were expected to wrap the coal particles and causing Tmax advanced, and S2 decreased. This influence is more conspicuous when higher density liquid is prepared. As for the effect of TOC is attributed to the inclusion of chemical compounds. Based on the overall effect of density liquid in pyrolysis, zinc bromide is finally chosen as the density liquid for separation because of its better linear correlation, low price, and cleanness after washing. The sample used is high volatile bituminous coal form Miocene Shihti Formation in Taiwan, collected from Yu-Feng mine near Sanshia, Taipei County. Three maceral mixtures were prepared after specific gravity 1.22, 1.30, 1.35 were chosen as thresholds for separation. The separation results indicate that the macerals with specific gravity <1.22 had 40% exinite about triple enrichment of the original sample; macerals with specific gravity 1.30-1.35 were primary vitrinite and some limited exinite; macerals with specific gravity >1.35, contained very few exinite. In the pyrolysis, the macerals with specific gravity <1.22 exhibit lower Tmax and S3, and higher S2. On the other hand, macerals with specific gravity >1.35 exhibit higher Tmax, S3, and lower S2. As for the parameters of macerals with specific gravity 1.30-1.35 were in between of the previous two maceral mixtures. Finally, there was no notable variation in S1 with specific gravity. However, it is noticed that S1 might be underestimated after washing.