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某些天然矿物质对煤液化催化加氢活性的研究 总被引:2,自引:0,他引:2
对中国某些天然矿物质以及一些冶金企业的精矿、尾矿和废渣的煤液化催化和加氢活性及其影响因素进行研究和探讨;并把它们与催化加氢活性较好的人工合成FeS2进行了比较,以寻找适合于中国今后实现煤炭直接液化工业化可用的催化剂资源。 相似文献
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煤的一段加氢液化使用的催化剂有可弃性催化剂,铁和钼氧化物及溶于水或油的催化剂和浸渍催化剂,其中以Co-Mo/Al_2O_3,Ni-Mo/Al_2O_3和钼酸铵为最广泛;黄铁矿能促进煤向油的转化,但却降低了脱硫率:Fe(OH)3-MoO_3-S在较低和较高温度下都是一种较活泼的催化剂;SnMo混合物明显优于纯SnO_2或无助催化剂的MoO_3/Al_2O_3;硫化的Mo(CO)_6是一种性能很好的煤加氢液化催化剂。 相似文献
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以硫酸亚铁为铁源,硫化钠为沉淀剂,采用液相沉淀法合成了超细FeS催化剂。以四氢萘为溶剂,反应温度430℃、氢初压6.0 MPa、反应时间60 min、溶煤比2∶1条件下,探讨超细FeS催化剂对五彩湾煤直接液化性能的影响。结果表明:硫酸亚铁基超细FeS粒子形貌均一,呈细棒状;五彩湾煤直接液化实验的油产率、液化率和转化率,以2.0%(wt,以活性金属元素计,相对于干燥无灰煤,下同)超细FeS为催化剂的实验分别达到56.15、73.29和81.21%(wt,相对于干燥无灰煤,下同),高于相同条件下,以3.0%分析纯Fe2O3为催化剂的实验产率(分别是44.00、49.33和62.05%)。 相似文献
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煤中矿物质在煤气化中的作用 总被引:4,自引:0,他引:4
本文以文献为基础,讨论了煤中矿物质对煤气化的催化作用、抑制作用、矿物质之间以及矿物质与外加催化剂的相互作用,提出在这一领域值得进一步研究的问题。 相似文献
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High- and low-temperature ashes from feed coal, coal extract solution and filter cake from a two-stage coal liquefaction process have been studied by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray fluorescence (SEM/EDX). Hydrocracking experiments using alumina support only, in place of the active Ni/Mo catalyst on alumina, were also carried out, with trace metal analysis of the coal extract solution feed and hydrocracked extracts using atomic absorption and emission spectroscopy. The major mineral transformations occurring were of pyrite to pyrrhotite and the fixation of organic sulphur by calcium carbonate. Mineral particles were not observed in the coal extract solution ashes, even under high magnification, and the study indicated that size alone was not a determining factor as to whether a coal mineral was to be found in a coal-derived liquid. None of the trace metals was deposited on the alumina support under hydrocracking conditions, in marked contrast to the results obtained with the normal Ni/Mo catalyst. These results lead to the conclusion that for the deposition of trace elements to occur a reaction must take place and hence the trace elements must be chemically bound in some form. 相似文献
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Previous work showed that the solvent extraction yield of coal increased as a result of chemical reactions such as formylation, reductive acylation, acylation, amidomethylation, alkylation, reduction and depolymerization. In the work described in this Paper, dmmf coal obtained after demineralization with mixed HF-HCI acids was used for solvolytic extraction studies after depolymerization, alkylation, acylation, amidomethylation, reductive acylation and reduction reactions. In comparison with the original coal, mineral matter free coal showed less increase in extractability as a result of these reactions indicating that mineral matter present in the original coal was acting as a promoter for these reactions. 相似文献
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The fine-scale mineral matter in three US coals has been analysed via scanning transmission electron microscopy (STEM). The samples observed were a North Dakota lignite, a Kentucky bituminous, and a Pennsylvania semi-anthracite. Specific mineral types, differing among the three coals examined, appear to predominate at this fine size scale (particles ? 200 nm in diameter). Fe-rich and Ba-rich minerals in the lignite, a Ti-rich mineral in the bituminous and Ca-rich and Ti-rich minerals in the semianthracite were the predominant species found. The inherent mineral content in the observed organic background also differed from coal to coal. The distributions of mineral species in the size range ? 200 nm reported herein do not reflect the distributions in the larger size ranges obtained by more macroscopic techniques. 相似文献
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Magnetic separation and thermo-magneto-chemical properties of coal liquefaction mineral participates
Sulphide solid particulates have been successfully separated from solvent-refined coal (SRC) liquid streams by high-gradient magnetic separation (HGMS) preceded by a sulphidation pretreatment in an H2S-rich gaseous atmosphere. This pretreatment is derived from studies of the properties of dry sulphide residual liquefaction solids, treated in an atmosphere of various H2/H2S compositions. Procedures have been devised for promoting rapid conversion of the weakly magnetic hexagonal pyrrhotites to the more strongly magnetic monoclinic form at a temperature intermediate to those of the SRC dissolver and the magnetic separation stage. 相似文献
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The sulphur distribution among the char, oil and gas obtained after hydropyrolysis of a high-sulphur (4.3 wt%) and high-calcite (7.3 wt%) coal has been investigated. The chars were examined by scanning electron microscopy coupled with an energy dispersion analyser and by X-ray diffraction. The proportion of the combustible and non-combustible sulphur in the char has been determined. Hydrogen pressure promotes reaction with sulphur but the sulphur content of the chars increases from 3 to 4.5 wt% when the temperature is increased from 616 to 845 °C. This increase in sulphur is a consequence of the reaction between hydrogen sulphide, produced during hydropyrolysis of coal, with the alkaline-earth mineral matter to produce alkaline-earth sulphide. The SEM and X-ray diffraction images show that in the char formed at 780 °C the sulphur, calcium and magnesium are localized in the same compounds. This is not the case when hydropyrolysis is performed at lower temperature. Combustion of the chars produces only <0.6 S02 MJ?1 compared to 2.2 g S02 MJ?1 for untreated coal. X-ray diffraction has shown that the sulphur in the char is oxidized and fixed in the ashes mainly as CaS04 and also some as MgS04. Although sulphur remains partly in the chars after hydropyrolysis, 75% of it is non-combustible. The hydropyrolysis of a high-sulphur coal containing calcite, produces a char which may be used as a clean fuel. 相似文献
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The transformation of pyrite to pyrrhotite and gypsum to anhydrite is well known during coal liquefaction. Most coals, except extremely fresh ones, contain various iron sulphates resulting from the oxidation of pyrite and marcasite. The reduction of iron sulphates to pyrrhotite during liquefaction is shown with the degree of reduction being temperature dependent. The formation of pyrrhotite from the iron sulphates is important because pyrrhotite is considered to catalyse hydrogénation reactions. 相似文献
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The effects of minerals on product compositions from rapid pyrolysis of a Pittsburgh Seam bituminous coal were investigated. Whole, demineralized, and mineral treated samples of pulverized coal were heated in 100 KPa helium or 6.9 MPa hydrogen at 1000 K s?1 to temperatures of up to 1300 K. Yields of char, tar and individual gaseous products were determined as a function of time-temperature conditions. Clays, iron-sulphur minerals, and quartz had few effects on pyrolysis in helium. Calcium minerals decreased yields of hydrocarbon products and increased yields of CO in helium pyrolysis. Calcite and clays decreased yields of CH4 from hydropyrolysis, whereas iron-sulphur minerals had little effect on pyrolysis at 6.9 MPa H2. Whole coal results were similar to demineralized coal results under all conditions. 相似文献
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在高温沉降炉上,进行了高氯高碱准东煤、低氯低碱准东煤和由低氯准东煤处理制得的调质准东煤在含不同浓度HCl的模拟空气中的燃烧实验。利用DLPI进行了颗粒物的分级收集,对其质量粒径分布和矿物元素分布特性进行了讨论分析。结果表明,高氯高碱准东煤的超细模态颗粒物生成量和峰值粒径均明显大于其他两种煤,其主要成分为Na和Cl。Ca的迁移特性与其形态密切相关,原煤中的Ca主要以无机矿物形式存在,主要迁移进入粗颗粒物而对超细颗粒物生成贡献较小。气氛中加入不同浓度HCl气体后,低钠煤和调质煤产生细颗粒物中Cl含量均升高,但生成量无显著变化。表明HCl并未显著促进矿物的气化,但会促进NaCl形式矿物蒸气的形成,进而促进成核形成超细颗粒物。 相似文献
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Low temperature ash (LTA) samples prepared from nine US coals were characterized by X-ray diffraction. X-ray fluorescence, and surface area analyses. The results showed that illite, kaolinite, quartz and pyrite are major components in LTAs and that ratios of some LTAs decreased significantly after H2 treatment implying the occurrence of a partial reduction of pyrite during this treatment. Surface areas of LTAs increased drastically on H2 treatment but decreased after exposure to sulphur and nitrogen compounds in activity testing. Correlations for the surface areas of LTAs before and after H2 treatment were found in terms of clay content and element concentrations. 相似文献