5.17 An ESP is treating the flue gas from a coal combustion unit and

achieving a 97% PM removal efficiency. Suddenly the efficiency

drops to 92%, but the gas flow rate has remained exactly the same.

a. Estimate the ratio of the new effective drift, velocity (w.) to the

old we

b. Under the old conditions (while achieving 97% efficiency), the

fly-ash resistivity was measured at 3.16 (10)10 ohm-cm. Esti-

mate the value of the new drift velocity, m/min.