Precipitation, electrostatic industrial data

The electrostatic precipitator in Example 2.2 is typical of industrial processes the operation of most process equipment is so complicated that application of fundamental physical laws may not produce a suitable model. For example, thermodynamic or chemical kinetics data may be required in such a model but may not be available. On the other hand, although the development of black box models may require less effort and the resulting models may be simpler in form, empirical models are usually only relevant for restricted ranges of operation and scale-up. Thus, a model such as ESP model 1 might need to be completely reformulated for a different size range of particulate matter or for a different type of coal. You might have to use a series of black box models to achieve suitable accuracy for different operating conditions. 

Fig. 4.3. Schematic of dry rod and plate electrostatic precipitator (after Oglesby and Nichols, 1978). The rods have sharp horizontal protrusions (nails) which promote corona formation. Dusty gas flows between the plates and around the rods. A large electrical potential (60 000 V) is applied between the rods and plates. This negatively charges the dust particles - causing them to approach and adhere to the positive collection plates. The dust is gathered by periodically rapping the plates, causing sheets of dust to fall into dust bins below, Fig. 4.4. Table 4.2 gives industrial precipitation data.

The results of Fig. 2.7 indicate that a significant fraction of particles in the nanometer size range will escape from electrostatic precipitator. for /i/oot values of the order of 10 ion sec cm . Such particles tend to form in high-temperature processes such as coal combustion, incineration, and the smelting of ores. Data are lacking on nanoparticle emissions from industrial electrostatic precipitators treating gases from coal-fired power plants or smelters. 

While. H. J. (1963) Industrial Electrostatic Precipitation, Addison-Wesley, Reading, MA. This highly readable monograph contains much practical operating data as well as discussions of fundamentals. 

---