Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal＇s petrologic characteristics and its maceral distribution to determine the maceral＇s contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin＇s unique depo- sitional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petro- graphic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos＇ coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good physical conditions so that pore water can maintain a long-term s
减缓以至最终有效控制能源生产利用过程中二氧化碳的排放,是中国能源生产面临的重大挑战。文章从提高能源利用效率和转化效率以及二氧化碳的捕集、分离和利用等方面介绍了中国二氧化碳减排的各种技术现状,并对二氧化碳减排技术的发展方向作了初步探讨,为中国二氧化碳减排及利用前景提供了一定的参考。燃煤过程中二氧化碳的减排是关键,洗煤技术、高效清洁煤技术等都可有效减少二氧化碳排放;分离捕集二氧化碳可利用燃前捕获、化学链燃烧技术、吸收分离法等。二氧化碳地质埋存包括油气藏埋存、深部盐水层埋存、煤层埋存和深海埋存。其中在油气藏埋存的同时进行EOR(Enhanced O il Recovery)是二氧化碳地质埋存的最佳方式。随着各项技术的完善,中国二氧化碳减排必将取得显著成效。
Based on analysis on X-ray diffraction, the metamorphic grade of coal in southeast Qinshui Basin was discussed, and a precise evaluation of coal rank through XRD analysis was made, in addition, the correlation of coal rank and vitrinite reflectance （Ro） was compared. XRD spectra of coal shows （002）-band and γ-band, and based on fitting calculation and multi-peak separation methods, the values of 2θ002 and 2θγ can be obtained, as well as corresponding intensities I002 and Iγ, consequently the coal rank can be quantized as the ratio of I002 and Iγ, that is coal rank=I002/Iγ. The research shows that the values of θ002 and θγ increase with the metamorphic grade, and a very good linear positive correlation exists between calculated Coal Rank and Ro.
Hao LIUWen-Hui HUANGWei-Hua AOCheng-Peng TANGuang-Lei RENXiao-Xia LUHuan WANEr-Ping FAN
