The document discusses nitric acid manufacturing, highlighting its properties, such as being transparent, yellowish, hygroscopic, and corrosive. It outlines various production methods including reactions with Chile saltpeter, electric oxidation of air, and high-pressure techniques used in single and dual pressure plants. Additionally, it describes the role of catalysts and the concentration methods for nitric acid, stressing the competitive costs of different plant types.

1. Nitric Acid Manufacturing
Class Lecture By
Engr. Ghulam Abbas

2. Nitric Acid
• Transparent
• Yellowish colour(due to NO2 emission)
• Hygroscopic
• Corrosive and attack all metals
• 78 C boiling point and -42C its freezing
point
• 100 % HNO3 only stable at below 0C

3. Manufacturing methods
• From Chile Saltpeter
• NaNO3 and H2SO4 react to produce
NaHSO4 and HNO3
• Electric Oxidation of Air (N2 & O2)
• N2 & O2 react (in the presence of
electricity) to form NO and more O2
produces NO2 and this is then mixed with
H2O to produce HNO3

4. By Catalytic Oxidation of NH3
• HNO3 is produced by High pressure
method (Dupont Plant or American Plant)
Raw Materials
• Liq NH3
• Air
• H2O

5. Conti..
• NH3 is produced by reaction
• N2+3H2 to 2NH3 at 500C and 200 Atm
and Iron oxide act as catalyst.
• N2 is obtained by fixation and H2 through
processing of Natural gas
• Air consists of 79%N and 21% O2
• H2O for absorption of Nitrogen per oxide
and for raising steam

6. Catlayst
• Platinum, Rhodium alloy composed of
90% Pt and 10%Rh
• Rhodium promotes catalytic actvity of Pt
and called as promoter.
• Rh also act as erosion resister
• Catalyst is in the form of 80 mesh gauze

7. Types of Plant
• Two types
• Single pressure Plant (American / Dupont
plants)
• Dual pressure plants also called European
Plants.
• Earlier,oxidation-absorption,reoxidation-
reabsorption process was operated at
Atmopheric pressure but it was expesive
as equipment was large. And HNO3 conc
55-55%

8. Conti..
• Single pressure plants have lower capital
cost and produced more steam
• Dual pressure unit has lower catalyst cost
and a slight higher yield.
• But overall costs are almost competitive

11. HNO3 Concentration
• 61-65% HNO3 by this method
• Distillation can be used for higher conc
upto 68.8% but not more than this as
azeorope is formed
• Distillation in the presence of
H2SO4(dehydrating agent) to give 70-75
% HNO3.