离心力场中瘦煤水煤浆的沉降失稳特性

将离心加速沉降和Turbiscan背散射光稳定性检测技术联合用于水煤浆稳定性分析,研究了一种瘦煤水煤浆经不同离心转速和离心时间处理后的沉降失稳特性。研究结果表明,水煤浆在静置状态下的失稳过程表现出显著的分层特征,而离心状态下主要表现出体系压缩过程而没有显著分层现象。但无论是静置还是离心处理,主导水煤浆失稳的核心因素均是颗粒的聚并和体系沉降。其中,颗粒的聚并主导了中部沉降区和底部沉淀区的演化过程,而体系的整体沉降则主导了表层的析水过程。研究发现,通过分析样品底部5 mm区域的稳定性指标可以辨析样品出现软沉淀的时刻及其演化期,以及硬沉淀开始生成的时间。这个发现为快速、定量和准确表征水煤浆稳定性提供了参考。

Sedimentation of lean coal water slurry in centrifugal field

A novel method combining centrifugation and backscattering technology was applied to analyze the stability of coal water slurry(CWS). The sedimentation behaviors of CWS prepared with a lean coal treated at different centrifugal speeds and centrifugal times were studied. The results indicate that the sedimentation of CWS in standing condition showed a significant delamination characteristic,while in centrifugal condition it mainly showed a system-compression characteristic with no significant delamination phenomenon. However,whether it was in static or centrifugal treatment, the core factors that lead to the CWS instability were particles coalescence and system subsidence. The particles coalescence dominated the evolution of CWS instability of the sedimentation area at the middle as well as the settling area at the bottom,while the system subsidence dominated the water liberation at the supernatant. It was found that the stability index at the bottom 5 mm of the sample,whether in the static or centrifugal condition,could be used to identify the occurrence time and the evolution period of the soft deposition,and the time when the hard settling began to generate. This finding provided a valuable reference for the rapid,quantitative and accurate characterization of coal water slurry stability.