Manufacturing process of n ox, hno3 BY OSTWALDS PROCESS,AMOINIUM NITRATE BY STENGELE METHOD,AMONIUM SULPHATE FROM GYPSUM,AMONIUM PHOSPHATE

1. Manufacturing process of NOx,
HNO3 and NH4 salts
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2. Presented by
Group 4
Arifa khanom-170512
Mafia aktary-170513
Souvik biswas soumma-170514
Dipta das-170541
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3. NOx compounds
In atmospheric chemistry, NO x is a generic term for the nitrogen
oxides that are most relevant for air pollution, namely nitric oxide and
nitrogen dioxide. These gases contribute to the formation of smog and
acid rain, as well as affecting tropospheric ozone.
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4. Formation of nitrogen oxides compound
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5. Manufacture of HNO3 by Ostwald’s Method
Principle
• The conversion of ammonia to nitric acid simply occurs as a result of
oxidation.
• This particular oxidation reaction gives us the corresponding nitric
oxide.
• Further, when the nitric oxide is oxidized nitrous gases are formed
and those gases can trap water molecule.
• As a result, we obtain nitric acid.
• Catalytic oxidation involving 02 is used where ammonia will give rise
to the product.
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6. Manufacture of HNO3 by Ostwald’s Method
Raw materials
• Ammonia
• Water
• Air
• Catalyst (platinum-rhodium gas)
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7. Manufacture of HNO3 by Ostwald’s Method
STEPS IN THE PRODUCTION
• Oxidation of ammonia NH3
• Oxidation of nitric oxide
• Absorption of NO2
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8. Manufacture of HNO3 by Ostwald’s Method
• Ammonia, prepared by Haber's process is scrubbed with sodium
hydroxide and then freed from water by refrigeration. Ammonia, is
purified from oil and Fe203.
• Purified ammonia is vaporized in a continuous steam evaporator.
• Air is compressed to 6.8 atmospheres, filtered and preheated to
about 300 °C by passing through a heat exchanger.
• Ammonia is mixed with purified and preheated air in the proportion
1:10 by volume.
• The mixture of gases (NH3,air) is compressed to a pressure of 100 psi.
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9. Manufacture of HNO3 by Ostwald’s Method
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NH3-air
Oxidation
tower

10. Manufacture of HNO3 by Ostwald’s Method
Primary oxidation (formation of nitric acid):
Oxidation of nitric acid is carried out in catalyst chamber in which one part of
ammonia and eight parts of oxygen by volume are introduced. The
temperature of chamber is about 800°C. This chamber contains a platinum
gauze which serves as a catalyst.
Chemistry of primary oxidation:
Oxidation of ammonia is reversible and exothermic process. Therefore
according to Le-Chateliars principle, decrease in temperature favors the
reaction in forward direction. In primary oxidation, 95% of ammonia is
converted to nitric oxide(NO).
4NH3 + 5O2 4NO + 6H2O
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11. Manufacture of HNO3 by Ostwald’s Method
Secondary oxidation (formation of nitrogen dioxide)
• Nitric oxide gas obtained by the oxidation of ammonia, is very hot. In
order to reduce its temperature, it is passed through a heat
exchanger where the temperature of nitric oxide is reduce to 150°C.
Nitric oxide after the cooling, is transferred to another oxidizing tower
where at about 50°C, it is oxidizing to NO2
2NO + O2 2NO2
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12. Manufacture of HNO3 by Ostwald’s Method
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NH3-air
Oxidation
tower

13. Manufacture of HNO3 by Ostwald’s Method
Absorption of NO2 ( formation of HNO3 ):
• Nitrogen dioxide from secondary oxidation chamber is introduced
into special absorption tower.
• NO2 gas passed through the tower and water is showered over it. By
the absorption, nitric acid is obtained.
3NO2 + H2O 2HNO3 + NO
• Nitric acid obtained is very dilute. It is recycled in absorption tower so
that more and more NO2 get absorbed. HNO3 after recycle becomes
about 60% concentrated.
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14. Manufacture of HNO3 by Ostwald’s Method
Concentration:
• Nitric acid cannot be concentrated merely by boiling because it forms
constant boiling mixture. Concentration of nitric acid is done by
following methods.
• Concentration of HNO3 by H2SO4 : In this process, concentrated
sulphuric acid (93%) is fed to the top of silicon-iron or stoneware
tower and 61-65 % nitric acid is fed just below the top. The vapors
leaving the tower are 90% HNO3.The H2SO4(70%) obtained at the
bottom is re-evapourated to 93 % or used as such elsewhere in the
plant.
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15. Manufacture of ammonium salts
There are three kinds of ammonium salts
• Ammonium nitrate
• ammonium sulphate
• ammonium phosphate
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16. Manufacture of NH4NO3 by Stengel method
Principle:
• Ammonium nitrate plants are operated in conjugation with NH3 and
HNO3 plant, which are the raw materials for its manufacturing.
Raw materials:
• Ammonia NH3 (Haber's Process)
• Nitric acid HNO3 ( Oxidation of ammonia)
Chemical reaction:
HNO3 + NH3 NH4NO3
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17. Manufacture of NH4NO3 by Stengel method
Process flow chart:
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Prills are Dried, Coated (by clay) and taken to packing plant for Packing.
Cooler (used to solidify )
Air is blown through melt (so water is removed and melt containing only0.25%
moisture produce directly)
Passed into a cyclone(separate steam and solution quickly)
React in packed tower
Super heated NH3 vapor (145°C) + Preheated conc HNO3(60%)(165°C)

18. Manufacture of NH4NO3 by Stengel method
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19. MANUFACTURE OF (NH4)2SO4 FROM GYPSUM
Raw Materials :
• Ammonia
• Carbon Dioxide
• Gypsum
Chemical reaction:
2NH3 + H20 + CO2 (NH4)2CO3
(NH4)2CO3+ CaSO4 (NH4)2SO4+ CaCO3
CaCO3 CaO + CO2
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20. MANUFACTURE OF (NH4)2SO4 FROM GYPSUM
Process flow chart:
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CaCO3 obtained as by product is used as a raw material for the
dried in a rotary drier at 1500oC to get ammonium sulphate crystal
The solution is evaporated and the crystals are centrifuged
The slurry produced is vacuum filtered and the calcium carbonate cake
washed and dewatered
finely ground gypsum or anhydrite is fed into the aqueous solution of ammonium
carbonate in large reactor,
Liquid ammonia and CO2 is absorbed in absorbing tower and form ammonium carbonate

21. MANUFACTURE OF (NH4)2SO4 FROM GYPSUM
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22. Manufacture of AMMONIUM PHOSPHATE
• Monoammonium phosphate (MAP):
Anhydrous ammonia added to liquid phosphoric acid gives
monoammonium phosphate (MAP). It is a fertilizer or fertilizer
intermediate with high P2O5 content of about 55% and nitrogen
content 11-12%.
• Diammonium phosphate (DAP) :
With more ammonia, technical grade diammonium phosphate (DAP)
containing 16 to 18% nitrogen and 20 to 21 % phosphorus (46% P2O5 )
is formed
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23. Manufacture of AMMONIUM PHOSPHATE
Raw Materials Basis:
• Diammonium phosphate
• Ammonia
• Phosphoric
Reactions:
NH3 + H3PO4 NH4H2PO4
NH3 + NH4H2PO4 (NH4 )2HPO4
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24. Manufacture of AMMONIUM PHOSPHATE
Process flow chart:
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Dried ammonium phosphate is screened and send to storage
Granules of ammonium phosphate dried in a dryer
Product mixture containing ammonium phosphate mixed with KCl which feed to the
granulator
Neutralization reactions take place in reactors
Excess quantity of ammonia is collected from top of the reactor and recycled to before
reactor
In case of production DAP ammonia is feed through 2nd and 3rd reactor
Liquor ammonia is feed through bottom of reactor + phosphoric acid is feed from top

25. Manufacture of AMMONIUM PHOSPHATE
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26. Thanks to all
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