In the synthesis of HNO 3 from NH 3 and air, the 10% NH 3 --air mixture is passe
ID: 1819834 • Letter: I
Question
In the synthesis of HNO3 from NH3 and air, the 10% NH3--air mixture is passed over a Pt-wire gauze (80 mesh) of 30 layers depth. Assuming the reaction to be totally controlled by gas-phase mass transfer, compute the NH3 conversion. The j factor of Satterfield-Cortez for gauzes is
j = 0.94 Re^-0.7 dw u/ = Re
and contact time is for n layers
(dw/u) *n 0
0
where = 0.5 is the void fraction and dw is the wire diameter. Assume (a) plug flow and (b) CSTR behavior. Finally for a bulk gas temperature of 800c calculate the surface temperature at the point of 50 percent conversion, the Reynolds number dw u/ is 30* Total pressure is 7 atm. The reaction is 2NH3 + 5/2 02 ----> 2N0 +3H20.
Explanation / Answer
Yes