Oxidation of Ammonia by Air

​
outlet temperature in °C
700
Ammonia is oxidized by air to form nitric oxide, as the first step in the production of nitric acid. The two principal reactions that occur are
4
NH
3
(g)+5
O
2
(g)→4NO(g)+6
H
2
O(v)
(reaction R1) and
2
NH
3
(g)+
3
2
O
2
(g)→
N
2
(g)+3
H
2
O(v)
(reaction R2). The inlet and outlet conditions are given in the reactor's flowchart. You can set the temperature of the outlet stream. The extent of reaction R1 is

ξ
1
=22.5mol/min
, while the extent of reaction R2 is

ξ
2
=5.0mol/min
.
The standard enthalpies of reactions R1 and R2 are
Δ
0

H
r,1
=-904.74kJ/mol
and
Δ
0

H
r,2
=-633.11kJ/mol
, respectively. All of the heat requirements for the formations are obtained from[1, Appendix B1].
This Demonstration computes the heat added to the reactor

Q
in kW. For this purpose, we make use of the energy balance equation for reactive systems:

Q
=Δ

H
=

ξ
1
Δ
0

H
r,1
+

ξ
2
Δ
0

H
r,2
+
∑
i
out


n
i

H
i

-
∑
i
in


n
i

H
i

(i.e. the heat of reaction method). The specific enthalpies of all components are computed using the temperature-dependent expressions of the constant-pressure heat capacities given in[1, Appendix B2]. In addition, we chose as reference states the molecular species
Air(g)
,
N
2
(g)
,
O
2
(g)
,
NH
3
(g)
,
NO(g)
and
H
2
O(v)
at 25 °C and 1 atm.

References

[1] R. M. Felder and R. W. Rousseau, Elementary Principles of Chemical Processes, 3rd ed., New York: John Wiley & Sons, 2004.

Permanent Citation

Housam Binous, Ahmed Bellagi
​
​"Oxidation of Ammonia by Air"​
​http://demonstrations.wolfram.com/OxidationOfAmmoniaByAir/​
​Wolfram Demonstrations Project​
​Published: September 13, 2016