Operation examples of emission control systems Thus, from an economical perspective industry practice is to provide electrode spacing of the order of 300/350/400/450/500 mm. To meet today’s stringent pollution control regulations, the efficiency of an ESP has to be very high, about 99.98% or more, for handling high resistivity ash. A decrease in electrode spacing would result in lower migration velocity, resulting in higher capital expenditure. 14.9 thus the total capital expenditure gets reduced. As a result, the total collection area is reduced substantially to achieve the desired collection efficiency, which is obvious from Eq. For constant current density and field strength, an increase in electrode spacing facilitates choosing a higher migration velocity as is clear from Table 14.6. The electrode spacing considerably influences the migration velocity. Sarkar, in Thermal Power Plant, 2015 14.2.10 Electrode spacingĮlectrode spacing is double the gap between discharge electrodes and collecting electrodes, which means the gap between two parallel collecting electrodes. Dry ESPs typically have a minimum collection efficiency with particles in the 0.5–1.0 μm size range. For extremely small particles, below 0.1 μm, Brownian motion assists in both charging and migration, which results in improved capture of smaller particles. As particle size decreases, the charging mechanism changes to diffusion charging, that is as the ions pass near the particles they induce a charge on them. The charging mechanism for particles greater than 2 μm in diameter is by field charging, which is collision between the corona ions and the particles ( Zhu, 2003). The amount of charge that can be placed on a particle is proportional to the surface area of the particle, with the larger particles requiring less energy for charging and being more readily precipitated than the smaller ones. The fine particles are then charged through collisions with the negatively-charged gas ions resulting in the particles becoming negatively charged. The gas is heavily ionized in the vicinity of the electrodes resulting in a visible blue corona effect. These gas molecules, with electrons attached, form negative ions. The electrodes discharge electrons into the flue gas stream, ionizing the gas molecules. Miller, in Advanced Power Plant Materials, Design and Technology, 2010 8.3.2 Particle charging (obsolete, Scotland) To prohibit to forbid.Advanced flue gas dedusting systems and filters for ash and particulate emissions control in power plantsī.G.To let fly to give expression to to utter.
#Discharge or electroweb free
To free of a debt, claim, obligation, responsibility, accusation, etc.* 1610, , act 3 scene 1 O most dear mistress, / The sun will set before I shall discharge / What I must strive to do.To accomplish or complete, as an obligation.
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