Question

Problem 3. (ESP) A single stage ESP operates with a voltage of 22 kV. The spacing between the collection electrodes of this single channel ESP is 10.0 cm and the anode-cathode spacing for the ESP is 5.0 cm. a) Calculate the electric migration velocity (wp) in m/s at 25°C in air for particles with the diameter 0.05 um, 0.5 µm and 5 µm. Assume the dielectric constant of the particles. Dp². is 10. Pressure is 1 atm. b) What assumption was made in the derivation of the equation for that may not be valid in for the calculation of the solution in a)? How would the calculated wp for the 0.05 µm particles change if we did not use that assumption? No need to calculate the value of wp. just describe the direction of its change (e.g., increases or decreases). c) Assuming the collection plates of the ESP are 3 m tall and 1 m long in the direction of gas flow and the gas velocity is 1.2 m/s. What is the graded collection efficiency of this ESP for the particle diameters in question a)? d) There are several modifications we could make to the ESP design to improve its collection efficiency. List one of those modifications and one tradeoff for implementing that change. (Multiple answers can be correct as long as you justify them). Solution hints -Capo K Ech Eco (Equ. 10 in reading notes) and follow the steps as in 3μ a) Use equation w = similar solved example problem (week 5). b) Check Rec and then calculate collection efficiency accordingly.