Hno3 lecture
- 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.