ABSTRACT

Screening is an indispensable unit operation that is used extensively in many industries to separate particulate materials into different size fractions. A banana screen has high screening efficiency and is widely used for coal classification. In this study, the kinematic characteristics and velocity distribution of the banana screen surface during equal-thickness screening were investigated. High-speed dynamic test system results showed that the migration velocity and distance of different screen surface stages increase with running time from point 1 to point 5. Based on the experimental data and Box–Behnken response surface methodology results, the best screening effect occurred when the angle of eccentric blockψ was 100°, the excitation frequency f was 34 Hz and the feed rate Q was 3 kg/s. Furthermore, the sequence of influencing degree of various factors on screening efficiency η followed the order: f > ψ > Q. The actual screening efficiency was 92.993% when the operating conditions wereψ = 103°, f = 32 Hz, and Q = 3.5 kg/s, indicating a satisfactory screening performance of coal using a banana screen.

摘要

筛分是必不可少的单元操作，广泛用于许多行业，将颗粒材料分离成不同尺寸的部分。香蕉筛筛分效率高，广泛用于煤炭分级。本研究对香蕉筛面在等厚筛分过程中的运动学特性和速度分布进行了研究。高速动态测试系统结果表明，从第 1 点到第 5 点，不同筛面阶段的迁移速度和迁移距离随着运行时间的增加而增加。根据实验数据和 Box-Behnken 响应面方法学结果，最佳筛分效果出现在偏心块角度ψ为 100°，励磁频率f为 34 Hz，进给速度Q为 3 公斤/秒。此外，各因素对筛分效率η的影响程度依次为：f > ψ > Q。当运行条件为ψ =103°、f =32Hz、Q =3.5kg/s时，实际筛分效率为92.993%，表明香蕉筛对煤的筛分性能令人满意。