Shell粉煤气化炉大渣块形成机理探讨

摘要

为了弄清实际生产过程中Shell粉煤气化炉大块渣的形成机理,文章运用XRD、SEM-EDX技术,对比分析气化炉稳定运行期间排出的灰渣和堵渣停车期间采集的大块渣的矿物组成、表观形貌及微区化学组成。结果表明：在Shell气化炉内大块渣形成期间,煤中含铁和含钙矿物存在明显的富集和析晶现象,在高温还原气氛下含钙矿物与石英形成大量低温共熔物—钙长石,钙长石在熔融状态下易吸附小块渣样,从而使渣块增长变大;含铁矿物质在气化炉里逐渐演变成（Fe-S-O）共熔体,这种物质具有很强的吸附粘结性,从而使渣块迅速增长变大。%In order to make clear the formation mechanism of large slag in Shell gasifier during the practical production,mineral composition,surface morphologics and micro-chemical composition were analysed by XRD and SEM-EDX compared slags of the stable operation with large slags during the parking due to slag-blocking.The results showed that iron-bearing minerals and calcium-bearing minerals in coal had obvious enrichment and crystallization phenomenon during large slags formation in the Shell gasifier.In the high temperature and reducing atmosphere,calcium-containing minerals and quartz formed lots of eutectic mixture known as anorthite which could absorb small slags in molten state,so that made slag grow bigger.Iron-bearing minerals gradually evolved into（Fe-S-O） eutectics which had a strong ability to absorb and adhere small slags,so that made slag grow bigger rapidly.