绝缘粉体在流化床中摩擦起电产生严重的危害。静电流态化工程利用外加电场的作用使带静电颗粒均匀稳定地流态化，是煤气化、合成树脂等重要化工过程强化热质传递、消除静电危害的新途径。本申请课题以新型的气相法聚乙烯流化床反应器为研究与应用背景，利用XPS、Faraday筒、精密天平、以及动态粉体静电-声发射在线联合测量等手段和CFD模拟计算手段，探索静电荷在粒径分散的同质聚合物粉体中的转移、分布的规律，以及化学吸附质对动态粉体静电增强或抑制的调变规律；研究新的受力环境下颗粒分类、流型转变、气泡运动规律及其受外加直流/交流电场的影响规律；研究壁面边界层静电场的调变规律，指导壁面防颗粒静电团聚技术的开发；研究外加电场控制的高荷质比细粉均匀分散悬浮机制与流体力学控制的低荷质比的粗颗粒流态化机制之间的协调，提高流化床稳定性和可调控性。为静电特性利用、新工艺开发提供普适性的科学理论指导。

Frictional electrification of the insulating particles can represent a serious problem for gas-solids fluidized bed reactors at very low humidity. Since electrostatic fluidization can be stabilized by the presence of an imposed electric field, which is of great importance to intensification of heat and mass transfer and prevention of electrostatic hazard for many highly important processes, such as, coal gasification and synthetic resin production. Toward to innovation of new process for gas phase ethylene polymerization fluidized bed, the objective of this work is to tackle three important problems experimentally by means of XPS, Faraday cages, high precise balance, electrostatic probes and acoustic emission measurement, and theoretically by CFD simulation. Firstly charge segregation dependence on particle size will be obtained for triboelectrically charged powder material in consideration of adsorption on particle surface in order to enlarge or alleviate electrostatic charge artificially. Secondly, under the new circumstance of hydro- and electro-dynamics, criterion of fluidized particle classification, flow pattern transition, bubble movement will be re-examined comparably with and without imposed DC/AC electric fields. Effect of imposed field on the agglomeration of fines near the wall region of fluidized beds will be mainly focused on with aim for problem solving. Finally, a methodology will be conceived to approach a possibility for electrostatic fluidization of a powder system with broader size distribution, the coarser particles having lower charge-to-mass ratios are mainly controlled by bubbling fluidization, meanwhile fines having higher charge-to-mass ratios are controlled by electro-mechanics within one fluidized bed. Based on the cooperation of these two mechanisms, stabilization and adjustability of electrostatic fluidized bed are needed to be illustrated quantitatively in this work to give a theoretical basis for process intensification in electrostatic fluidized bed. The success of this work will advance our fundamental understanding and provide direct evidence for utilization of electrostatics and innovation of new processes with highly efficiency.