旋转摩擦电选对电站粉煤灰高效脱碳基础研究

Fly ash decarbonization to convert fly ash from an industrial solid waste to a high value added resource will have substantial economic, environmental, and social benefits by mitigating its environmental pollution and facilitating its widespread utilization. A study of the innovative rotary triboelectric separation process provides a new and more effective process for fly ash decarbonization by enhancing particle charging uniformity and efficiency. Research topics include: (1) uniform charging mechanisms of fly ash particles in the rotary tribocharging chamber; the motion trajectory and separation mechanisms of fly ash particles of different components in the continuous gas-solid flow field; (2) synergistic effects of process parameters in generation of premium fly ash products with less than 2% carbon; (3) relative velocity profile of gas, velocity profile of particles, and particle motion trajectory distribution in the separation chamber; mathematic models for fly ash particle motion and separation in the external electric field; (4) independent control and optimization of the charging and separation process; (5) design a 2.1×2.8×1.0 m continuous separation testing system from the experimental data to provide guidelines for commercialization of the technology.

对火电厂粉煤灰进行脱碳研究，旨在把粉煤灰由固体工业废物变成可高附加值利用的宝贵资源，对减少环境污染及推动粉煤灰资源化综合利用将产生重大经济、环境和社会效益。基于旋转摩擦充电方式下的粉煤灰电选脱碳研究，对提高矿物颗粒群充电的均匀性，为粉煤灰干法高效脱碳提供新的方法。.研究内容：（1）粉煤灰矿物颗粒在旋转摩擦充电器内的均匀带电机理，多组分粉煤灰物料在连续气固流场内运动、分离规律。（2）基于烧失量小于2% 的超级优质粉煤灰产品的电选过程参数的协同优化；（3）静电分选区内气体相对速度场、颗粒速度场、颗粒运动轨迹的分布情况；粉煤灰颗粒在静电力场中的运移、分离规律，建立相关数学模型；（4）充电和分选过程的独立控制技术和工艺最佳化。（5）基于实验结果，设计 2.1×2.8×1.0 m 连续分选试验系统，为工业化提供理论基础。

课题以电厂粉煤灰为研究对象，详细分析了其在旋转摩擦电选机内的运动规律。借助Fluent软件模拟了旋转摩擦室内的气固两相流场，结果表明：摩擦轮转速及进风气流显著影响旋转摩擦室内气流分布；通过Fluent-EDEM耦合揭示了颗粒碰撞次数、电荷量与的关系，确定了粉煤灰颗粒荷电量最大化的参数，并确定了粉煤灰高效摩擦起电区域；建立了电场力作用下的颗粒运动动力学方程；通过单因素试验揭示了影响粉煤灰分选效果的主导因素：摩擦轮转速、极板电压、给料速度，并设计了BBD正交试验，确定了主导因素及交互作用对粉煤灰烧失量的影响，得到了烧失量为5%，-45μm筛余10.6%的符合一级粉煤灰标准的优质粉煤灰，最终形成了一套粉煤灰高效分选技术原型，具有一定的实践指导和广泛推广意义。