Dust Removal Spray Tower; FPT Ch14 Q5

Worked solution for Question 5, Chapter 14 (available as free download at www.particles....) in Fundamentals of Particle Technology. The question asks for the single target efficiency of the drops within a spray tower, used to remove dust from a gas stream. Initially the overall collection efficiency is calculated, and then the single target efficiency from a rearranged form of the efficiency calculation. It is shown that the 150 micron water drops only has 30% target efficiency. This could be increased considerably by using larger water drops, the most efficient drop size being 600 to 1000 microns. This would lead to an improved spray tower collection overall efficiency. Thus this type of analysis can be performed on an existing system, to determine how an equipment performance increase can be made with a quantifiable estimate. In the second part of the video, for equation derivation, please note that at 25 minutes and 40 seconds dx is used when dz should have been used. The term dz being a small increment in tower height, hence Adz is the volume of that increment.