The first objective of this book is the analysis of the dominant mechanisms involved in the removal of particles using a Sieving Electrostatic Precipitator (SEP). The second objective concerns the study of the SEP pressure drop. The main collecting mechanisms in the SEP prevent the release of the bulk of the toxic substances passing through it into the ambient air. The influence of those mechanisms is studied separately in this thesis. This is accomplished by calculating the effect of Coulomb forces on the particle coagulation rate, collision frequency for particles in the laminar shear flow, collision frequency for particles in Brownian motion, and the collection of particles on a cylindrical obstacle. An important feature of this dust removal device, pressure drop, is simulated and analyzed for different screen configurations and different inlet velocities. This is carried out by utilizing the software FLUENT. In addition, user defined function (UDF) is used to enhance the FLUENT simulation resulting in more realistic results.