Removal of micron‐size particles from gases by turbulent deposition and diffusiophoresis

Abstract

When one gaseous or vapour component diffuses across a space occupied by another component, there is a tendency to entrain and remove particles in the micron size range suspended in that space. This phenomena is called diffusiophoresis. The object of this work was to study the application of this phenomenon as a means of air pollution control when pollutant particles are suspended in a gas stream in turbulent flow. Under these conditions turbulent deposition also results in removal of particles from the gas stream. The test system chosen for study was sulfuric acid droplets suspended in air, with water vapour as the diffusing component. A concentration gradient was established by passing the mixture through a vertical tube whose walls were cooled. Experimental particle collection efficiencies agreed with efficiencies calculated from a theoretical model of the system. The energy requirement of this pollution control technique was analyzed.