粉煤气化工业装置煤粉黏附力表征及其流动性评价

摘要

In the process of pressurized entrained-flow pulverized coal gasification,pulverized coals often form arching-bridge phenomenon in the lock hopper feeding unit due to the small particle size,the large specific surface area,and the resulting cohesive force among particles.In this paper,by using the industrial demonstration unit of SE (Sinopec-ECUST)-Gasifier pulverized coal gasification as the background,pulverized coal samples with different particle sizes as the research materials,and a combination of a continuum medium approach and a model of particle-particle interaction as the analytical method,a model to predict the cohesive force was built.By comparing the flow properties,the interparticle force as well as its relationship with the gravity of different samples,the effects of mean particle size and fine particle content on the flowability and the discharge process of pulverized coal were revealed.The results predicted by the model were also verified by the visualization platform in the lab and the industrial unit.The research results indicate,as the mean particle size decreases and the fine particle content increases,the flowability of pulverized coal becomes weaker and there is a transition from arching-bridge to arching-free flow during the discharge.The research work can provide a useful reference for improving the flowability of feeding pulverized coal and enhancing the stability of pulverized coal feeding system.%气流床粉煤加压气化工艺中,煤粉颗粒粒径小、比表面积大,受颗粒间黏附力影响,煤粉在锁斗下料单元经常出现结拱架桥现象.本文以SE(Sinopec-ECUST)-东方炉气流床粉煤加压气化工艺为工业应用背景,以典型粒径特征的煤粉样品为研究对象,采用连续介质模型与颗粒间作用力分析相结合的方法,建模求解煤粉颗粒间的黏附力.通过对比不同样品的流动参数、颗粒间作用力及其与重力的相互关系,揭示了平均粒径及细颗粒含量对煤粉流动性和下料过程的影响,并在实验室可视化下料平台和工业装置下料单元对上述结果进行了验证.研究结果表明,随着平均粒径降低、细颗粒含量增加,煤粉流动性减弱,下料逐渐从结拱架桥过渡至无拱自由流.本文为改善入炉煤粉流动性、提高煤粉供料系统运行稳定性提供了有效的参考.