Size an afterburner and specify the flow rate of methane needed to control 500 m3 min-1 of air from a rendering plant. The exhaust gasses are available at 200°C, and must be raised to 700°C and held for 0.8 sec to reduce emissions of odorous compounds. The burner requires ambient air at a mass ratio of 14:1.

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?