An experiment investigation of particle collection efficiency in a fixed valve tray washing column

The collection efficiency is one of the key parameters to evaluate the performance of washing columns, and the gas–liquid flow characteristic is an important factor affecting collection efficiency. In this work, the gas–liquid flow characteristic and its effect on collection efficiency in a fixed valve column have been investigated. The experimental results show that the fixed valve washing column is capable of generating higher gas holdup than a standard bubble column under similar situations. For different particle sizes, with increasing gas holdup, the changes of the trends in collection efficiency are different. For particles larger than 1 μm, the collection efficiency increases with gas holdup while for particles finer than 1 μm, the collection efficiency either decreases (0.5–1 μm) or decreases initially and then increases again (0.3–0.5 μm). The collection efficiency increases with liquid-to-gas ratio but decreases with bubble size, bubble velocity and particle loading. The contribution of each tray to the collection efficiency is different. A correlation is developed for predicting the collection efficiency of particles and the experimental values agree well with the predicted values.