Study on the effect of fractional composition and ash particle diameter on ash collection efficiency at the electrostatic precipitator
Chemical Industry and Chemical Engineering Quarterly
The goal of experimental investigations shown in this paper is to estimate the operating efficiency degree of the electrostatic precipitator on a real industrial plant (a the thermal power plant "Gacko" with the electric power of 310 MW, Bosnia & Herzegovina) and to use the obtained results as a base of periodical engineering or continual measurement and compare them with the investigations of other investigators. The investigation of the electrostatic precipitator performance was done
... to BAS ISO 9096:2003. In this paper, the electrostatic precipitator efficiency during the ash particle removal with a wide range of particle sizes from 1 to 250 μm is evaluated. The exploitational experience points out that electrostatic precipitators are efficient for the coals of different quality (coal particles with diameters bigger than 1 μm) and that they could be optimized during the exploitation itself and for some following processes (e.g., flue gas desulphurization). Within the measurement plane, the measurements were made on 20 points per section. It has been noticed that ash removal degrees obtained experimentally (3 investigations) have approximately equal value (95.93 to 97.78%). The best concordance with the results of experimental investigation shows the Deutsch equation, while theoretical models of Zhibin-Guoquan and Nobrega-Falaguasta-Coury do not correspond well to the results of experimental investigations. For the ash particles with the diameters less than 17.5 μm there is no good correlation between investigated theoretical models. The highest deviation of the model for ash particles with diameters less than 17.5 μm is notable in the case of using the Deutsch equation. Key words: electrostatic precipitator; collection efficiency; ash particles dimensions; velocity of flue gas; migration velocity of ash particle. The electrostatic removal of solid particles from flue gases has a wide application in the range of the industrial processes. The electrostatic removal of solid particles from flue gases operating is based on the principle that the gas is allowed to pass between two electrodes one of which is grounded (plate collecting electrode), and the other which is connected to the negative pole of high-voltage current (coronary electrode). The particles in the gas stream are electrically charged and separated from the flue gas under the influence of electric field. Flue gas process parameters (volume flow, temperature, velocity) and the parameters of the electrostatic precipitator (the length of the electric field, migration velocity of the ash particle, particle size distribution and the distance between plate collecting electrodes) have a big influence on the collection efficiency in an electrostatic precipitator. Many researchers [1-7] analyze the influence of these parameters on the particle collection efficiency in the electrostatic precipitators and often give contradictory conclusions. Different mathematical models were used in order to show that geometric characteristics of the electrostatic precipitators (length of collecting electrodes, the distance between collecting electrodes, migration velocity) have influence on their collection efficiency.