The influence of water-soluble and acid-soluble inorganic matter on sulphur transformations during pyrolysis of low-rank coals
The influence of water-soluble and acid-soluble inorganic matter on sulphur transformations during pyrolysis of low-rank coals
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DOI：
10.1016/s0016-2361(01)00078-3
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发表时间：
2001-11-01
期刊：
影响因子：
7.4
通讯作者：
Zhang, DK
中科院分区：
文献类型：
--
作者：
Telfer, M;Zhang, DK
对南澳大利亚鲍曼煤制备的原煤、水洗煤、酸洗煤以及Ca++和Na+离子交换的酸洗煤进行了程序升温热解（TPP）实验，研究了物理吸附（水溶性）和有机结合（酸溶性）无机物对热解过程中硫转化的影响。根据澳大利亚标准（木炭的湿化学分析）监测了200至900度之间硫形态的变化。通过扫描电子显微镜（SEM）和能量色散x射线分析（EDX）来解释硫的转变。在TPP过程中，观察到鲍曼原煤在400至500度之间比处理过的煤产生更少的硫。水溶性硫酸盐比其他水溶性无机物更能抑制有机硫在同一温度区域的分解，从而有助于硫的保留。据观察，酸溶性无机物可使硫的保留率提高500至600度。化学分析没有检测到相应的硫化物的形成，这表明酸溶无机物的存在将有机硫的分解抑制在500到600度之间。在800度和900度下去除的TPP炭的SEM-EDX和iDXi x射线图显示，硫确实与有机结合的无机物相互作用。Na与二氧化硅相互作用，在热解过程中形成高浓度的碳颗粒成分。两种类型的包裹体都含有高浓度的硫。钙在炭中富集，引发有机硫的分解，在800 ~ 900℃之间制备的炭中形成硫化钙。2001爱思唯尔科学有限公司版权所有。
Temperature-programmed pyrolysis (TPP) experiments are conducted on several samples prepared from a South Australian Bowmans coal, viz. raw, water-washed, acid-washed and Ca++ and Na+ ion-exchanged acid-washed samples, to study the influence of the physically absorbed (water-soluble) and organically bound (acid-soluble) inorganic matter on sulphur transformations during pyrolysis. Changes in sulphur forms between 200 and 900 degreesC were monitored according to Australian Standards, wet chemical analysis of chars. Interpretation of sulphur transformation was aided by scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX). During TPP, raw Bowmans coal is observed to evolve less sulphur than the treated coals between 400 and 500 degreesC. Water-soluble sulphates above other water-soluble inorganics, are found to contribute to the sulphur retention by suppressing the decomposition of organic sulphur in the same temperature region. Acid-soluble inorganics are observed to increase the retention of sulphur between 500 and 600 degreesC. Chemical analysis did not detect a corresponding formation of sulphides, suggesting that the presence of acid-soluble inorganics suppressed the decomposition of organic sulphur between 500 and 600 degreesC. SEM-EDX and iDXi X-ray mapping of TPP chars removed at 800 and 900 degreesC revealed that sulphur does interact with the organically-bound inorganics. Na interacts with silica and forms highly concentrated constituents in char particles during pyrolysis. Both types of inclusions were found to contain highly concentrated areas of sulphur. Calcium becomes enriched in the char to initiate decomposition of organic sulphur and form calcium sulphide in the char prepared between 800 and 900 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.