Elaborate the process description of urea production.

1. PREPARED BY-
UTKARSH GUPTA
CHEMICAL ENGINEERING
0904351031

2. IFFCO has four fertilizer plants in India:
 At Phulpur in Uttar Pradesh
 At Kalol in Gujarat
 At Kandla In Gujarat
 At Aonla in Uttar Pradesh

3.  IFFCO has completed conversion in its largest naphtha based
ammonia urea complex at Phulpur into a gas based unit.
 IFFCO lead to enter an agreement with GAIL in 2004 for
supply of Reliquified Natural Gas (R-LNG).
 IFFCO’s urea is a major source of 46% of nutrients nitrogen
for crops.
 Urea also used as cattle feed supplement.
 It also has numerous industrial uses, as for production of
plastics.

4. PRODUCT CAPACITY PROCESS
Urea 2380 MT/Day Snam Progetti , Italy
Ammonia 1255 MT/Day Kellogg's, U.S.A

5. • Power generation plant
• Ammonia synthesis plant
• urea plant
• offsite plant
 reverse osmosis plant
 demineralization plant
 water softening plant

6.  R-LNG received from pipelines cracked by
Kellogg's process.
 Ammonia and Carbon Di-Oxide from the ammonia
plant, moved to the Urea plant.
 Steam generated in Ammonia plant is also used in
Urea plant.
3H2 + N2 2NH3 + Heat

7. Urea Plant consist following sections:
 H.P Section (32%)
 M.P Section(62%)
 L.P Section(72%)
 Vacuum Section(99.8%)
 Prilling Section

9.  NH3(l)and CO2(g)from the Ammonia plant fed
to a reactor at temperature of 168-170°C and a
pressure of 155 Kg/cm2.
2NH3 + CO2 NH2COO NH4 + 38.1K.cal/g.mol
NH2COONH4 NH2CONH2 + H2O
-7.1 K.cal/g.mol
 Carbamate recycled and attain a concentration
of 32%.

10.  A mixture of Carbamate, Urea, Ammonia and
CO2 send to the medium pressure(MP)
decomposer and in this section the
concentration of urea gain 62%.
 Low pressure section consist CO2 Absorber,
because we did not leave the CO2 in this form
into the environment.
 In this low pressure section the concentration
of Urea increase to the 72%.

11.  In vacuum section solution brings in 1st
vacuum at 0.3 atmospheric pressure and in 2nd
vacuum at 0.03 atmospheric pressure.
 In vacuum section concentration of urea
increase to 99.8%.
 With the help of molten urea pumps urea send
to the top of the Prilling tower.

12.  Urea has a melting point of 132.6 °C.
 Air by natural draft flows upward and counter
currently and cools and solidify Urea droplets.
 Solid prills fall to the bottom and sent on to a
belt conveyor by means of a rotating scrapper,
urea prills are then transported to bagging
plants through belt conveyor.

13. Moisture % by weight, maximum 1.0
Total N % by weight (on dry basis) minimum 46.0
Biuret % by weight, maximum 1.5
Particle size 90% of the material shall pass
through 2.8 mm IS sieve and
not less than 80% by weight
shall be retained on 1 mm IS
sieve.

14.  Corrosion
 Biuret Formation:
2 NH2CONH2 NH2 CO NH CO NH2 + NH3
(Urea) (Biuret )
 The formation of biuret is favored by higher
temperature, higher concentration of urea solution, low
NH3 content and higher residence time.