Nfl nangal urea plant (1)

Urea Process description of Nangal Plant

1. R-1LPR-2
1
NFL NANGAL & BATHINDA
Urea Plant
Presented By
Prem Baboo
Sr. Manager(Prod)
National Fertilizers Ltd, India

2. R-1LPR-2 2
Urea Processes used in NFL units
NANGAL: TechnimontTotal Recycle
Process.
BATHINDA & PANIPAT: MitsutoatsuC
Improved Process.
VIJAIPUR: Snamprogettiammonia stripping
process.

3. R-1LPR-2 3
NANGAL UREA PROCESS
BRIEF DESCRIPTION:
It is a Montedisontotal recycle process.
Plant is installed in April,1978.
Plant capacity is 1450 Te/day.
Commercial production after revamping started on
Feb 1
st
,2001.
Before revamping its capacity was 1000 Te/day.

4. R-1LPR-2 4
Plant Description
CO
2Compressor & H.P.Pumps
Urea synthesis.
Urea separation.
Recovery section.
Vacuum section.
Prilling section.
Waste water section.

5. R-1LPR-2 5
Specification Sheet
Ammonia at B/L
NH
3 99.5% by weight
Water 0.5% by weight
Carbon Dioxide at B/L
CO
2 98.99% (Vol.)
H
2 0.6 to 1.5% (Vol.)
CH
4 0.1 to 0.15% (Vol.)
H
2S 0.65 ppm (Vol.)
CH
3OH 6.00 ppm (Vol.) for old compressor
CH
3OH 1000 ppm (Vol.) for new compressor

6. R-1LPR-2 6
Specific Consumption
Ammonia 0.574Te/Te of urea
Carbon dioxide0.745 Te/Te of urea
Steam 30ata 1.23 Te/Te of urea
Power 135 kwh

7. R-1LPR-2 7
CO
2Compressor
There are two motor drivenreciprocating compressors
Old Compressor
No. of Stages 3
Capacity 17510 Nm
3
/hr.
Suction/Discharge press. 11/220 Kg
RPM 300
Motor Power 2250KW
Oxygen content maintained 2200ppm

8. R-1LPR-2 8
NEW COMPRESSOR:
No. of Stages 4
Capacity 9500 Nm
3
/hr.
Suction/Discharge press. 1.5/220 Kg
RPM 350
Motor Power 2400KW
Oxygen content 3500ppm

9. R-1LPR-2 9
Ammonia feed pumps
There are three reciprocating plunger pumps
Make Peroni
No. of plungers 5
Pulsation dampener nil
Capacity 53NM
3
/hr. each
Suction pressure. 30Kg/cm
2
Discharge pressure 220 Kg/cm
2

10. R-1LPR-2 10
Ammonia feed pump
One no. ammonia pump (New) having less
capacity 25NM
3
/hr.
Two ammonia pumps run at 100% load.
Ammonia is directly taken from ammonia
plant at 30 kg & fed to reactors at
220kg.Before feeding to reactors it is pre
heated up to 80°C.

11. R-1LPR-2 11
Carbamate feed pumps
There are four reciprocating plunger pumps
Make Peroni
No. of plungers5 in old & 3 in new
Pulsation dampeneronly in new pump
Capacity 53M
3
/hr. each
Suction pressure.70Kg/cm
2
Discharge pressure 220 Kg/cm
2
Three pump run at 100% load.

12. R-1LPR-2 12
Urea Synthesis
Urea reactor {Old}
Volume 50M
3
No. of trays 14
Type of traysHigh eff. Casaletrays.
Temp. Bott./Top184/196
O
C
Pressure 220Kg/cm
2
Liner SS 316 L
Thickness 12mm

13. R-1LPR-2 13
Urea Synthesis
Urea reactor {New}
Volume 33M
3
No. of trays 9
Type of traysHigh eff. Casaletrays.
Temp. Bott./Top184/198
O
C
Pressure 220Kg/cm
2
Liner 2RE69
Thickness 6mm

14. R-1LPR-2 14
New Reactor
Fresh ammonia & carbon dioxide are fed to
mixer, then to carbamatecondenser, where
ammonium carbamateis formed. Heat of
reaction is taken out in the form of 6 .0 ata
steam generation. The hot carbamateflows to
reactor R-2 where residence time is enough
to get 69% conversion.Itis once through
reactor, no carbamatesolution is fed to it.

15. R-1LPR-2 15
Old Reactor
The rest of CO2 & NH3 are fed to old
reactor. All the carbamatesol. of the plant
fed to old reactor.
Both reactor outlet joins & pr. Is controlled
by PRC-1 at 220kg.

16. R-1LPR-2 16
Reactor feeds
The expected best operating condition are:
New sec. Old sec.
Capacity (TPD) 600 1050
Pr. (ata) 220 220
Temp. (ºc) 196 196
N/C 2.9 2.75
H/C 0 0.7
Conversion (%) 69 55

17. R-1LPR-2 17
Conventional Process
Decomposition:
NH4COONH2 +Heat=2NH3 + CO2

18. R-1LPR-2 18
Urea Separation.
1
st
stage
Pressure 70 Kg/cm
2
Temperature 185
O
C
Urea conc. 54.5%
2
nd
stage
Pressure 12 Kg/cm
2
Temperature 150
O
C
Urea conc. 65%
3
rd
stage
Pressure 3 Kg/cm
2
Temperature 130
O
C
Urea conc. 72%

19. R-1LPR-2 19
Recovery Section
Pressure 1.5 Kg/cm
2
Temperature 125
O
C
Outlet conditions
NH
3 0.04%
Urea 1.0%

20. R-1LPR-2 20
Vacuum Section
1
st
stage vacuum system
Pressure 0.35 ata
Temperature 128
O
C
Urea conc. 95%
2
nd
stage vacuum system
Pressure 0.04 ata
Temperature 138
O
C
Urea conc. 99.6%

21. R-1LPR-2 21
Prilling Section
Tower
Height 104.5mtr
Free fall ht. 80mtr
Diameter 22mtr
Air flow 8,00,000 nm
3
/hr
Urea in emission 40mg/nm
3
.
Scrapper type conical
Bucket
Make Tuttle/Simco
Number TX-267, 268 & 130

22. R-1LPR-2 22
Product Quality
Total Nitrogen 46.5%
Moisture 0.35%
Biuret 0.8-0.9%
Mean prill dia 1.75mm
Sieve analysis
Over size nil
Proper size 98.5%
Under size 1.5%

23. R-1LPR-2 23
Waste Water Section
Feed at 100% load35m
3
/hr
Feed water analysis
NH
3 3.00%
UREA 1.2%
Hydrolyser pr. 20Kg/cm
2
Hydrolyser temp. 198
0
C

24. R-1LPR-2 24
Waste Water Section
Distillation tower
Pressure top 4.5Kg/cm
2
Pressure bottom 5.5 Kg/cm
2
No. of trays 33+12
Outlet water analysis
NH
3 40 ppm
Urea 35 ppm

25. R-1LPR-2 27
Plant Start up
Reactor is filled with dilute solution.
In case of empty reactor, it is to be filled with
start up solution.
In case of cold start up, reactor solution is
first heated up to 125
O
C .
First stage{70ata} remain by passed.

26. R-1LPR-2 28
Plant is started in once through operation.
Once through operation means the solution is
send to urea solution tank and Carbamate is
send to start up solution tank from 2
nd
stage.
Ammonia feed to reactor and pressure is
maintained at 150ata for 5 minutes and then
CO
2is send to reactor.
Plant Start up

27. R-1LPR-2 29
Reactor pressure will increase according to the
temperature and feed ratio.
As the temperature and pressure reaches to the
desired condition then the Carbamate from 2
nd
stage
is diverted to the 1
st
stage.
As the level of 1
st
stage condenser increases, start
the Carbamate pump and feed Carbamate to the
reactor.{known as total recycle}.
Plant Start up

28. R-1LPR-2 30
After total recycle, temperature and pressure
of each stage are maintained.
The urea solution is sent to vacuum section.
After normalizing vacuum section, melt urea
diverted towards bucket.
Plant Start up

29. R-1LPR-2 31
Objective of revamping
Optimum utilization of ammonia plant capacity.
Increase in urea plant capacity by 450 MTPD.
Improvement in urea prills quality.
Reduction in specific energy consumption for urea
from 10.26 G cal. To 9.4G cal. Per MT of urea.
Reduction in dust emission.

30. R-1LPR-2 32
Revamping
Project Cost; Rs.161Crores
Project executed by;M/s. Urea Casale
Switzerland.

31. R-1LPR-2 33
Major equipment added:
CO
2 compressor.
NH3 pump.
Carbamate pump.
Urea reactor.
Methanol scrubber.
Urea melt pump
New vacuum distiller {HE9}

32. R-1LPR-2 34
Additional vacuum condenser.
New circular Prilling tower.
High efficiency trays in old urea reactor.
Major equipment added:

33. R-1LPR-2 36
Urea Quality After Revamping
Over size reduced to nil.
Temperature in summer reduced from 90
O
C
to 55
O
C.
Crushing strength increases from 350
gm/prill to 650 gm/ prill.
Urea dust emission reduced . Now it is
< 50mg/nm³.

34. R-1LPR-2
Urea casale’shigh efficiency tray

35. R-1LPR-2