Task $1$: Electrostatic Precipitators $(4$P$)$

An electrostatic precipitator should be designed for removal of fly ash from a power plant. The

emitted particles are assumed to have a diameter of $x=30m,$ the number concentration is given by

$2*{10}^{12}\frac{1}{m^3}$ and the particle relative permittivity is $2\mathrm{.}8.$ The field strength at the collection electrode

is $0,6M\frac{V}{m}.99,9\%$ of these particles are to be removed from the gas.

Field charge limit: $Q_{\text{f}\text{i}\text{e}\text{l}\text{d}\text{,}\text{m}\text{a}\text{x}}={}_0{x}^{2}E(1+\frac{2{}_p-2}{{}_p+2})$

Deutsch$-$equation: $,T(x)=1-$exp$\{-w(x)\frac{A}{(V^{})}\}$

Calculate the particles charge as the field charge limit and assume Stokes regime for settling!

c$)$ Which is the required collection electrode area to achieve the requested cleaning efficiency for a

volumetric flow rate of $1000000\frac{m^3}{h}.(2)$

Data:

Viscosity of air: $18$ PPas, vacuum permittivity: $8\mathrm{.}85*{10}^{-12}A\frac{s}{V}m,$

elementary charge: $1\mathrm{.}6*{10}^{-19}$ As$/$electron

d$)$ Problems may arise from low dust resistivity in dry electrostatic precipitators. Explain the

processes at the collecting electrode in case that low dust conductivity causes problems. Which

is the technical term for this phenomenon. Give a sketch of a current,voltage$-$diagram of under

these conditions! $(2)$