Transformations of sodium during gasification of low-rank coal
Transformations of sodium during gasification of low-rank coal
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DOI：
10.1016/j.fuproc.2005.06.006
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发表时间：
2006-11
影响因子：
7.5
通讯作者：
A. Kosminski;D. Ross;J. Agnew
中科院分区：
文献类型：
--
作者：
A. Kosminski;D. Ross;J. Agnew
研究了含有两种形式钠的高硫南澳褐煤的特殊制备形式;作为羧酸盐，形成煤有机物的一部分或作为可溶性盐（NaCl）。研究了气化环境（气体类型、温度和时间）对钠的转化和气化程度的影响。与煤中存在的高水平硫的理论平衡计算相反，在羧酸钠转化时没有发现硫化钠形成。实验证实，而在富硫煤的气化或热解过程中形成碳酸钠。钠被发现蒸发，与钠释放较高的气化过程中在蒸汽或二氧化碳比在氮气中热解。含氯化钠的煤中钠和氯的释放不成比例。几乎所有的氯都是在850 °C的气化和热解过程中释放出来的。钠的释放量几乎是氯的一半，推测是以氯化钠蒸气的形式。残余热解炭中碳酸钠的鉴定证实了氯化钠与来自煤羧酸基团的氢的反应。在含有氯化钠的煤的焦炭中既没有发现硫化钠也没有发现氢氧化钠。
Specially prepared forms of a high-sulphur South Australian lignite containing sodium in two forms; as a carboxylate, forming a part of the coal organic matter or as soluble salt (NaCl) were investigated. The influence of gasification environment (gas type, temperature and time) on the transformations of sodium and the extent of vaporisation were studied. Contrary to theoretical equilibrium calculations for the high levels of sulphur present in the coal, no sodium sulphide formation was found upon the transformation of carboxylate sodium. Experiments confirmed rather the formation of sodium carbonate during gasification or pyrolysis of the sulphur-rich coal. Sodium was found to evaporate, with sodium release higher during gasification in steam or carbon dioxide than for pyrolysis in nitrogen. The release of sodium and chlorine from coal containing sodium chloride was disproportionate. Almost all of the chlorine was measured to have been released during gasification and pyrolysis by 850 °C. The release of sodium was nearly half of that of chlorine and inferred to be in the form of sodium chloride vapour. Identification of sodium carbonate in the residual pyrolysed char confirms the reaction of sodium chloride with hydrogen from coal carboxylic acid groups. Neither sodium sulphide nor sodium hydroxide was identified in char for coal containing sodium chloride.