错流碟片旋转超重力场中液膜体积分率的实验研究

Experiments of Liquid-Film Volume Ratio in Cross-Current Rotating Discs Packed Bed

错流碟片旋转填充床反应器可有效脱除燃煤烟道气中的二氧化碳和其它有害成分,但液体分布状态对反应速率有很大影响,研究液膜的体积分率可为该类型反应器的设计提供有效的依据参数;实验研究了碟片转速、液体流量、气体流量、碟片间距和碟片开孔率与液膜体积分率的关系,用每张碟片底部对应液体收集器储存并测量碟片表面液膜的体积流量,用高速摄像机记录不同条件下液膜的存在状态和变化规律。研究表明随碟片转速增加液膜分率降低,增强的离心力促使液膜破裂,但液滴的甩出速率增加,促使液滴二次聚并,有不连续液丝产生。增大入口液体流量,液膜分率减小,液膜厚度变化缓慢,空间液滴增大。增大气体流量,液膜分率减小,厚度变薄,碟片表面附着液膜被吹散,促使液体雾化。液膜分率随碟片间距增加减小,提高碟片间距可有效减少液滴二次聚并;碟片开孔率增大液膜分率减小,提高碟片开孔率可有效降低碟片表面液膜的连续性,促使液膜分裂。

Cross-current rotary discs packed bed reactors have the ability of effectively removing the carbon dioxide and harmful components in flue gas of coal combustion. Since in the rotating bed the contact surface between liquid and gas affects the chemical reaction rate of removing harmful gases seriously, the study of liquid-film volume ratio of the reactor can provide the basic information for the design of rotary discs packed bed reactor. Therefore the relations between liquid-film volume ratio and rotary speed, liquid and gas input flowrate, discs interval distance and disc surface drilling ratio were investigated respectively. The situation and variation of the liquid-film was recorded by a high-speed video camera and the data were treated with a processing unit connected with a computer; the liquid-film volume attaching to the discs surface was measured by collection-container settled beneath each disc. The experiment results show that, with increasing the rotation speed of the rotary discs, the liquid-film volume ratio decreases, some droplets will collide together once again, and a bit of discontinuous liquid-wires occur. On the other hand, with the increase of input liquid flowrate, the liquid-film volume ratio decreases, the liquid-film thickness almost keeps unchanged, and the droplet diameter increases obviously. It was also found that, with increasing the input gas flowrate, the liquid-film volume ratio and the liquid-film thickness decrease; the continuity of the liquid-film on the disc can be decreased effectively by increasing the drilling ratio of the disc surface.