General In an engineering report prepared for the API in 1961 by the University of Cincinnati@l. the function of an ~Iectrostatic precipitator is described as removing particles (solid or liquid) from gaseous streams. This is achieved by passing the gas between a pair of electrodes- a discharge electrode at a high potential and an electrically grounded collecting electrode. The potential difference must be great enough so that a corona discharge surrounds the discharge electrode. Under the action of the electrical field@ gas ions formed in the corona move rapidly toward the collecting electrode and transfer their charge to the particles by collision with them. The electrical field interacting with the charge on the particles then causes them to migrate (drift) toward@ and be deposited on@ the collecting electrode. When the particles are solids@ the dust layer that forms on the colIecting electrode is removed by intermittent rapping that causes the deposit to break loose from the electrode. In effect. this returns the dust to the gas stream but not in its original finely divided state. As a result of cohesive forces developed among the particles deposited on the electrode@ the dust is returned as agglomerates which are large enough for gravity to cause them to fall into dust hoppers below the electrodes. Reduced to its essentials@ the electrostatic precipitator acts as a particle agglomerator combined with a gravity settling chamber. The electrical mechanisms required for precipitation of particles are: (l) addition of an electrical charge to the particles and (2) application of an electrostatic force that causes the charged particles to migrate (drift) toward the collecting electrode. In the usual industrial electrostatic precipitators@ both are supplied simultaneously@ and the precipitator acts as a single-stage unit. A typical industrial precipitator is diagrammed in Figure 12-1. The Appendix defines typical terminology for precipitators. *REFERENCES on page 12-12.
API PUBL 931 C12-1974 history
1974API PUBL 931 C12-1974 MANUAL ON DISPOSAL OF REFINERY WASTES VOLUME ON ATMOSPHERIC EMISSIONS CHAPTER 12 - ELECTROSTATIC PRECIPITATORS