Electrostatic deposition-precipitation

Microcapsules are non-dense spherical shaped volumes. They are formed by a shell (polymeric wall in this case) with an empty volume inside that can be used to encapsulate compounds. The structure of the shell (a thin, dense layer, or a thick, porous layer, etc.), together with its nature (chemistry, material), determines the release rate of the encapsulated compound. There are several ways to obtain microcapsules. Some of these methods are based only on physical phenomena, certain are based on polymerization reactions and others combine both physical and chemical procedures. Most authors agree in classifying them all in two different groups chemical processes (like in-situ polymerization or desolvation in liquid media) and mechanical processes (e.g. spray drying or electrostatic deposition) [44]. A novel technology for microcapsule production, based on the employment of microdevices in continuous mode, has been presented [45]. Immersion precipitation is used in this case, in a way similar to that explained for flat membranes. 

Air cleaning systems are often used to remove dust or vapors from plant or process exhaust streams. Dust collecting systems such as filters or electrostatic precipitators that handle heavy loads of dust are usually designed to be self-cleaning, but it is stiU. necessary to enter the air cleaner periodically for inspection or repair. Dust deposits inside the equipment are likely to be stirred up and inhaled by unprotected workers. Baghouses are particularly likely to cause exposure because large amounts of dust may be retained in the cloth and released when the bags are handled. 

Wet electrostatic precipitators (WESP) are used for removal of liquid contaminants such as sulfuric acid mist, aerosols, and particulate matter. The acid mist and aerosols are typically formed in a WGS by condensation of SO3. Unlike dry precipitators, wet precipitators do not require rapping to remove the dust. The collected mist and particulate matter form a liquid film that runs down a vertical collecting plate. In some cases, a continuous spray of liquid is used to prevent solids deposition on the collecting plates. 

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