高灰熔点煤加压气流床气化特性

Gasification Characteristics of Coal with High Ash Fusion Temperature in Lab-Scale Down-Flow Gasifier

在25kg／h规模的沉降式加压气流床气化实验装置上，研究了高灰熔点煤种在固态排渣温度范围内的气化特性及灰渣熔融特性．结果表明，气化温度、碳转化率均随O／C物质的量比的增加而增加，冷煤气效率则随O／C物质的量比的增加呈现先增大后减小的变换规律；本实验条件下，最佳O／C物质的量比在1．0—1．2之间，此时冷煤气效率达最大值（42％左右），相应碳转化率为90％；对最佳工况下气化炉底部、旋风分离器和布袋除尘器内的灰渣进行SEM分析表明，该工况下气化炉底部、旋风分离器内的灰渣在整体上仍以固态形式存在，只是有部分低熔融成分发生熔融，其熔融部分的粒径在数微米左右，而布袋除尘器内的灰渣没有发生熔融现象．

Gasification characteristics and slagging behavior of high ash fusion temperature coal were studied in a 25 kg/h lab-scale down-flow gasifier with a temperature range from 1 300℃ to bellowing ash fusion temperature which is suitable for dry ash extraction. The results show that both gasification temperature and carbon-to-gas conversion increase with the increase of O/C molar ratio. Cold gas efficiency gradually increases as O/C molar ratio rises until it reaches around 1.0 - 1.2, and then cold gas efficiency will decrease at higher O/C molar ratios. Under this experimental condition, the optimal O/C molar ratio ranges from 1.0 to 1.2, and the corresponding cold gas efficiency and carbon-to-gas conversion are 42% and 90% respectively. SEM photos of slag on the bottom of the gasifier, and in the cyclone and the bag filter were also studied. The slag on the bottom of the gasifier and in the cyclone exist, on the whole, as solid except that some small parts of the size of several μm melt, while the slag in the bag filter remain unmelted.