Fly-Ash Scrubbing in a Tapered Bubble Column Scrubber

The wet scrubber offers great advantages over other devices as a particulate control device since the regulations for the particulate emissions from various sources are being tightened. This paper presents the scrubbing of fly-ash in a tapered bubble column scrubber using water. Experiments were carried out for studying the behaviour of the system in terms of various pertinent variables. Experimental results show that a very high removal efficiency of fly-ash can be achieved in the present system. Electrostatic effect was found to have an insignificant influence over the efficiency of collection studied. However, many other physical interactions are found to play vital roles in the collection efficiency. It was observed through experimentation that the system efficiently collected particles up to 20 μm size. Finer particles (<20 μm) could be collected by augmenting the system with further stages of operation. The present tapered bubble column has achieved 94% collection efficiency at a QL. QG−1 ratio of 5.0 m3 per 1000 ACM (actual cubic meter) as against 50–65% collection efficiency achievable in a standard bubble column with some modification in a single stage at a QL. QG−1 ratio of 10.17 m3 per 1000 ACM. Selection of any particulate control device is based on the performance of the system. In the light of this consideration a correlation is put forward for the prediction of the performance of the scrubber in terms of various pertinent variables of the system. The experimental values agree excellently well with the predicted values (within ±2.5% deviation). The tapered bubble column developed is found to be hydro dynamically, energetically and efficiency-wise much better than a standard bubble column.