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 adhesive-Fevicol)

• 3. For the manufacture of various glues (urea-formaldehyde or urea-melamine-formaldehyde). The latter is waterproof and is used for marine plywood

• 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.

• 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 Non-

hygroscopic 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.