The basic idea of all ESPs is to give the particles an electrostatic charge and then put them in an electrostatic field that drives them to a collecting wall. This is an inherently two-step process. In one type of esP, called a two-Stage precipitator charging and collecting are carried out in separate parts of the ESR. This type, widely used in building air conditioners, is sometimes called an electronic air filter. However. for most industrial applications the two separate steps are carried out simultaneously in the same part of the eSP
The basic idea of all ESPs is to give the particles an electrostatic charge and then put them in an electrostatic field that drives them to a collecting wall. This is an inherently two-step process. In one type of ESP, called a two-stage precipitator, charging and collecting are carried out in separate parts of the ESR. This type, widely used in building air conditioners, is sometimes called an electronic air filter. However, for most industrial applications the two separate steps are carried out simultaneously in the same part of the ESP
Figure 9.2 shows in simplified form a wire-and- plate ESP with two plates. The gas passes between the plates, which are electrically grounded (i.e voltage=0). Between the plates are rows of wires held at a voltage of typically -40 000 volts. The power is obtained by transforming ordinary alternating current to a high voltage and then rectifying it through some kind of solid-state rectifier On the plates the particles lose their charge and adhere to each other and the plate, forming a cake
Figure 9.2 shows in simplified form a wire-andplate ESP with two plates. The gas passes between the plates, which are electrically grounded (i.e., voltage = 0). Between the plates are rows of wires, held at a voltage of typically -40 000 volts. The power is obtained by transforming ordinary alternating current to a high voltage and then rectifying it through some kind of solid-state rectifier. On the plates the particles lose their charge and adhere to each other and the plate, forming a "cake
Solid cakes are removed by rapping the plates at regular time intervals with a mechanical or electromagnetic rapper that strikes a vertical or horizontal blow on the edge of the plate
Solid cakes are removed by rapping the plates at regular time intervals with a mechanical or electromagnetic rapper that strikes a vertical or horizontal blow on the edge of the plate
Some of the cake is always re-entrained thereby lowering the wastegas flowrate whereas enhancing the removal efficiency of the system If the collected particles are liquid, e.g., sulfuric acid mist, they run down the plate and drip off
Some of the cake is always re-entrained, thereby lowering the wastegas flowrate whereas enhancing the removal efficiency of the system. If the collected particles are liquid, e.g., sulfuric acid mist, they run down the plate and drip off
9.2 DIVIDING COLLECTION DEVICES Filters and scrubbers divide the flow into smaller parts where they can collect the particles Two types of filters, surface filters and depth filters, are commonly used in air pollution control
9.2 DIVIDING COLLECTION DEVICES Filters and scrubbers divide the flow into smaller parts where they can collect the particles. Two types of filters, surface filters and depth filters, are commonly used in air pollution control