【作者】 王萍；

【导师】 胡浩权； 靳立军；

【作者基本信息】 大连理工大学 ， 化学工艺， 2013， 硕士

【摘要】 煤热解是煤化工中最重要的反应之一,是煤加氢、燃烧及气化的基础反应,热解始终伴随着这些反应过程。煤炭通过热解过程可获得焦炭、焦油及煤气等产品,低温热解可以提高煤转化过程中的经济性。在热解过程中引入催化剂,可影响煤热解过程及产品分布。本文以神木煤、脱矿物质神木煤及添加矿石煤样(煤／矿石=10：1)为实验用煤,在固定床反应器上考察了热解气氛、热解温度对神木煤热解行为的影响及添加不同矿石煤样在氢气气氛下的半焦产率及焦油产率的变化规律；并借助气相色谱(GC)对煤热解焦油的组分进行分析；在热重分析仪上研究了内在矿物质及外加矿石对神木煤热解及燃烧行为的差异性影响；利用热重-质谱联用(TG-MS)技术,研究了矿物质对煤热解过程中气体逸出规律的影响；通过对脱矿物质煤样及外加矿石煤样燃烧动力学的分析,讨论了矿物质对神木煤燃烧作用的机理。1)不同热解气氛(氢气、氮气、混合气(10%CO,25%CO2,25%CH4,40%H2)及温度下神木煤热解结果显示：热解温度和气氛会显著影响半焦产率和焦油收率。相同温度下,不同热解气氛所得半焦产率及焦油产率各有差异,半焦产率由高到低依次为：N2>混合气>H2,焦油产率随着温度的升高呈现出先增加后降低趋势。2)热重分析结果表明,煤中内在矿物质对神木煤热解及燃烧行为有着明显影响。脱矿物质煤样热解的最终转化率低于原煤,最大失重速率小于原煤,说明内在矿物质对煤热解过程具有促进作用；脱矿物质煤样最大燃烧速率所对应的温度比原煤降低了约26℃,表明内在矿物质抑制煤燃烧过程。3)外加矿石对神木煤热解产物、焦油组成及燃烧行为影响显著。氢气气氛下,添加矿石煤样的半焦产率及焦油产率均小于原煤,这可能是由于矿石催化焦油进一步发生裂解,生成气体分子。不同矿石对焦油产率影响不同。含有FeO(OH)的1#矿石可使煤的挥发分产率提高1.88wt.%。从热解焦油组成来看,外加矿石煤样热解所得焦油中烯烃和烷烃总含量明显减少,而苯、甲苯和苯酚等轻质芳香类化合物含量显著增加；1#矿石对燃烧的促进作用最为显著,添加1#矿石煤样最大失重速率所对应的温度比原煤降低了约25℃。4)通过对脱矿物质煤样及添加矿石煤样燃烧动力学的分析可以看出：在最大燃烧速率所对应的温度与燃尽温度间,煤燃烧均属于一级反应；脱除煤的内在矿物质可以有效降低其燃烧反应的活化能；不同矿石对煤燃烧反应表现出不同的作用：1#矿石促进煤的燃烧,2#矿石的作用不明显,3#矿石则抑制燃烧过程。更多还原

【Abstract】 Pyrolysis is the most important reaction in coal technology since it is the basic process for the manufacture of coke, tar and gases from coal and the initial and accompanying reaction of coal hydrogenation, combustion and gasification. Much milder reaction conditions are needed to meet the demand for energy saving and economical coal conversion processes. The catalysts are generally effective in coal pyrolysis and product distribution.Raw, demineralized and with additive of ores(coal/ore=10/1) Shenmu coal samples were used in this work. The effect of atmosphere, temperature and ores on pyrolysis of coal samples was studied in a fixed-bed, and tar compositions from pyrolysis of coal with different ores were analyzed by GC. Thermal gravimetric analysis (TGA) was used to investigate the effect of inherent-mineral and additive ores on coal pyrolysis and combustion characteristics. The effects of ores on gas evolution during pyrolysis were detected by TG-MS, and the kinetic parameters of coal combustion were determined.1) Pyrolysis atmosphere and temperature have great influence on coal pyrolysis. At the same pyrolysis temperature, active atmosphere could promote the pyrolysis reaction, and the relative sequence of char yield as follows:N2>Mix Gas(10%CO,25%CO2,25%CH4,40%H2)>H2. With the increasing temperature tar yield increases, but too high temperature resulted in the decrease of tar yield.2) The TGA study indicated that inherent minerals could promote coal pyrolysis, while inhibit coal combustion activity. The final pyrolysis conversion and the maximum rate of weight loss of demineralized coal are lower than those of raw coal, while the temperature with the maximum combustion rate of demineralized coal is about26℃lower than that of raw coal.3) Ores have great influence on coal pyrolysis and combustion behavior. Char and tar yields of coal with ores are lower than those of raw coal at the same temperature in H2. The low tar yield may belong to the catalysis effect of ores and lead to the tar into small molecular gas. Among three kinds of ores, No.1ore (main composition is FeO(OH)) could improve the volatile yield of coal pyrolysis, which increases by1.88wt.%(daf) compared to that without addition of ore. The GC analysis of tar indicated that the total content of olefin and alkane in tar from coal samples with ores decreases obviously, and the content of light aromatic compounds, such as benzene, toluene and xylene, increases. The No.1ore is the best additive in promoting coal combustion among three ores, which made the temperature of the maximum combustion rate decrease about25℃.4) The research on the effects of inherent-mineral and ores on coal combustion and the kinetic study indicated that the combustion kinetic can be described with a one-order reaction equation, and the demineralized coal has lower activation energy. Different ores have different effects on coal combustion. The No.1ore could promote coal combustion activity, and the effect of No.2ore is not obviously, and the No.3ore could inhibit coal combustion.更多还原