煤热解过程中冠醚对砷变迁行为的影响
首发时间:2012-06-01
摘要:运用真空管式炉热解装置考察煤热解过程中超分子化合物18-冠-6及二苯并-18-冠-6的添加对砷脱除率的影响,并结合逐级化学提取、密度分离、脱灰脱黄铁矿处理等实验方法,研究冠醚在煤热解过程中对砷变迁行为的影响。结果表明,在煤热解过程中不论是添加18-冠-6还是二苯并18-冠-6,随着热解温度的升高,砷的脱除率均高于团柏原煤热解时砷的脱除率,且添加二苯并-18-冠-6砷的脱除率高于添加18-冠-6时砷的脱除率。当热解温度为850℃,停留时间为30min时,原煤热解时砷的脱除率为30.63%,在煤热解过程中添加18-冠-6时砷的脱除率为33.21%,略高于原煤热解时砷的脱除率;添加二苯并-18-冠-6后砷的脱除率高达67.41%,明显高于原煤热解时砷的脱除率。逐级化学提取结果表明加入冠醚热解更有利于以硫酸盐和单硫化物结合态及稳定态形式存在的砷的挥发。
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Study on the influence of crown on arsenic behaviors during coal pyrolysis
Abstract:The influence of crown on behaviors of As at different temperatures and residence times were investigated during the pyrolysis of Tuanbo (TB) coal. The modes of occurrence of As were determined by sequential chemical extraction, density fractionation and demineralization. The results indicated that at the same temperatures and residence times, the arsenic removal adding dibenzo-18-crown-6 is higher than that when adding 18-crown-6, and are all higher than that of TB coal during slow-heating pyrolysis. When temperature is 850℃ and residence time is 30min, the arsenic removal of TB coal is 30.63%. At the same conditions, the arsenic removal adding 18-crown-6 is 33.21%, higher than TB coal; and the arsenic removal adding dibenzo -18-crown-6 is 67.41%, significantly higher than that of TB coal. From the results, we can see that adding crown can improve the arsenic removal during slow-heating pyrolysis, and especially more conducive to the arsenic which is mainly associated with sulfates & monosulfides and that in stable forms.
Keywords: coal slow-heating pyrolysis crown arsenic removal
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No.4479757607475133****
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