| 摘要: | 煤是一種混合物，包含了有機質、無機質、揮發份、水份等，藉由分離來富集所需成份有助於了解煤素質特性。煤素質的分離是利用各煤素質比重不同的原理，調製比重分離液並配合離心機進行分離。本研究欲了解煤素質分離後的熱裂分析特性，而在此之前須對分離液於熱裂分析中的影響進行試驗。並期日後能建立煤素質組成與熱裂分析的相對關係。 選擇三種無機化合物作為分離液的材料：溴化鋅、氯化鋅、碘化鉀，分別配置不同比重的溶液，將煤樣浸泡其中，再水洗及直接烘乾後進行熱裂分析。發現水洗過的樣本在各參數上都能回復至平均值；浸泡樣本部份則會因分離液材料熔點較低產生的包覆作用使Tmax提前、S2參數值降低，且分離液的比重愈大影響愈明顯。浸泡分離液對TOC的影響則是因分析樣品淨量不同所導致，水洗後亦可回復。綜合三種分離液的影響，以溴化鋅浸泡樣最接近線性行為，且水洗效果良好、價格低廉，故選用溴化鋅為分離液。 分離煤素質使用的煤樣是台灣中新世石底層之高揮發份煙煤，採自台北縣三峽鎮裕峰煤礦。選擇了三個分離區間：比重<1.22的部份可富集40%的膜煤素，約為原樣的三倍；比重1.30-1.35則以鏡煤素為主，又含少量的膜煤素；比重>1.35的部份由於膜煤素減少，使鏡煤素所佔比例提高。熱裂分析的結果發現，經過富集的煤素質組成可表現出煤素質的特性。在比重<1.22的煤樣中，Tmax、S3較低、S2則較大，表示具有較多碳氫化合物；比重>1.35的趨勢則相反，Tmax、S3較高、S2則較小，可能是由於比較上含較多曾受氧化的有機物；至於比重1.30-1.35的部份則在各參數上的數值皆居前兩者之間。在S1上則看不出有顯著隨比重變化的趨勢。但S1較易受到水洗的影響而流失，容易被低估，是需要注意的地方。 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. |
