基于低场核磁共振技术的水煤浆水分状态与定量分析

Quantitative analysis on water status in coal-water slurry based on low field nuclear magnetic resonance technology

水煤浆中水分状态与含量的变化是产生其宏观流变特性变化的根本原因,研究水分状态的迁移变化有助于从微观机理上阐释水煤浆流变特性的变化规律,进而为管道输煤系统工艺参数设计和优化提供依据。利用低场核磁共振技术,研究了不同粒径、不同浓度水煤浆中的水分状态及其迁移变化。研究结论表明：通过T2谱图辨别了水煤浆中吸附水、间隙水和自由水三种不同状态水分;三种水分会随着颗粒粒径和浓度的变化而发生迁移,即在一定粒径下,吸附水含量与浓度无关,间隙水的含量随着浓度的增大而增多,自由水的含量则随浓度的增大而减少;在一定浓度下,吸附水和间隙水量与粒径呈负相关,自由水量与粒径呈正相关;分析了吸附水、间隙水和自由水含量随浓度和粒径的变化规律,为相似条件下流变特性微观机理的认识提供参考。

Variation of water status and its content in coal-water slurry is the basic cause of rheological properties changes in slurry. Studies on water status can help to explain the change law of rheological properties from microscopic mechanism,and to provide the basis for the design and optimize of pipeline system. Based on low field nuclear magnetic resonance technology,the water status changes in slurries under different concentrations and particle sizes have been studied. Results show that： T2 spectra shows that there are three different water statuses mainly existed in coal-water slurry,which is adsorption water,interstitial water and free water. Contents of three water change with the different particle sizes and concentrations,namely under a certain particle size,adsorption water has no connection with concentration,interstitial water increase with the increase of concentration,and free water decrease with the increase of concentration. Under the same concentration,adsorption water and interstitial water negatively correlated with particle size,and free water and particle size were positively correlated. The change law of adsorption water,interstitial water and free water content with different concentrations and particle sizes are obtained to provide a reference for analysis of microscopic mechanism of rheological properties under the similar condition.