PRODUCTION OF UREA
• Urea is a white dry organic compound and a
crystalline substance and has minimum of 46%
Nitrogen calculated in dry state.
M.P: 132 deg C.
• Urea is made by reacting carbon dioxide (CO2) with
anhydrous ammonia (NH3) under pressure of 208
atm and temperatures of around 176.6 0C.
• Water is removed during processing and the molten
matter is either converted to prills or into granules.
• Urea can be produced as prills, granules, flakes,
pellets, crystals and solutions.
USES
• 1. Urea is highly soluble in water and is therefore
also very suitable for use in fertilizer solutions (in
combination with ammonium nitrate: UAN) and
as animal feed.
• 2. For the manufacture of plastics specifically,
urea-formaldehyde resin(Plywood adhesiveFevicol)
• 3. For the manufacture of various glues (ureaformaldehyde or urea-melamine-formaldehyde).
The latter is waterproof and is used for marine
plywood
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Specifications for Prilled Urea 46%N:
Nitrogen:46.0% min.
Moisture:0.3% max.
Biuret:1.0% max.
Granulation:1 – 4 mm 90-94% min.
Melting Point: 132 Degrees Celsius
Colour: Pure White Prilled
Free Flowing, Treated against caking, 100%
free from harmful substances.
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Specifications for Granular Urea 46%N:
Nitrogen:46.0% min.
Moisture:0.5 % max.
Biuret:1.4% max.
Granulation:2 – 4 mm 90-94% min.
MeltingPoint:132DegreesCelsius
Colour: Standard White or Pure.
Free Flowing, Treated against caking, 100% free
from harmful substances.
Market grades
• 1. Technical grade: 46% Nitrogen
• 2. Fertilizer grade: Coated with Nonhygroscopic dust such as Phosphate
rock/Lime stone, containing 40-42%
Nitrogen
• 3. Liquor: Mixtures of Urea in Ammonia
Solution
Principle raw materials:
1) CO2 from synthesis gas
2) NH3
• Process description:
• 1. Ammonia and CO2 are compressed separately
and added to the high pressure autoclave.
• 2. The Reactor is water-cooled due to the highly
exothermic nature of the reaction.
• 3. The Reactor is operated on a continuous basis; A
mixture of Urea, Ammonium Carbamate, Water and
unreacted NH3+ CO2 results.
Process description
• This liquid effluent is let down to 27 atms. and
fed to a flash-evaporator containing a gas-liquid
separator and condenser.
• Unreacted NH3, CO2 and H2O as a solution are
thus removed and recycled (in case of partial
recycle option).
• An aqueous solution of carbamate-urea is passed
to the atmospheric flash drum, where further
decomposition of carbamate takes place.
Process description
• The off-gases from this step can either be
recycled or sent to NH3 processes for making
chemical fertilizer.
• The 80% aqueous Urea solution can be used
as is, or sent to a vacuum evaporator to
obtain molten Urea containing less than 1%
water.
The molten mass is then sprayed into a prillng
or granular solidification tower.
Process description
• To avoid formation of bi-uret in percentages
greater than1%, the temp. must be kept just
above the Melting Point for processing times
of 1-2 sec. in this phase of the operation.