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R-1 E-1 MV-2 V-1 MV-3 SYNTHESIS SECTION SAIPEM PROCESS PRESENTED BY Prem Baboo National fertilizers Ltd. India. An Expert for www.ureaknowhow.com Fellow of Institution of Engineers India. Plant & Equipment's Designer
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Operation of urea fertilizers plant

Jan 23, 2018

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Page 1: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3

SYNTHESIS SECTION SAIPEM PROCESS

PRESENTED BY

Prem Baboo

National fertilizers Ltd. India.

� An Expert for

www.ureaknowhow.com

� Fellow of Institution of Engineers

India.

� Plant & Equipment's Designer

Page 2: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-32

POINTS TO DISCUSS

� START UP

� SHUT DOWN

� TROUBLE SHOOTINGS

Page 3: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-33

� Initial start up

� Cold start up

� Hot start up

Start Up

Page 4: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-34

Start Up

� Initial start up means:

– All the sections are depressurized and /or without process

fluids.

� Cold start up means:

– All the sections are pressurized with process fluids but HP

Reactor is empty and HP loop depressurized.

� Hot start up means:

– All the sections are pressurized with process fluids and HP

Reactor is full and HP loop pressurized.

Page 5: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-35

START UP

� CLEARANCE TO BE TAKEN FROM

1. MECHANICAL

2. ELECTRICAL

3. INSTRUMENT

� CLEARANCE TO BE TAKEN FROM

1. AMMONIA-II

2. UREA-I

Page 6: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-36

Start Up With Empty Reactor

General

� During this phase it has been assumed that all pre-

start operations have been completed together with

Mechanical check of the unit.

Page 7: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-37

Sealing Tests Of All Sections

� Purpose

– To eliminate leaks, if any, before charging process

fluids.

Page 8: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-38

Sealing Test

� Fluid

– Steam condensate.

� Temperature

– Ambient (cold test)

� Pressure

– Operating value

Page 9: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-39

Sealing Test Conceptual Procedure

� Admit the fluid from the lowest points and keep the

vent at highest points opened.

� Slowly increase the pressure to the test value.

� Check all flanges and connections in order to identify

leaks and eliminate them.

� If the pressure does not fall appreciably after 4 hours

the test can be considered satisfactory, otherwise it

will be necessary to look and to eliminate them and

then repeat the test.

Page 10: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-310

Very Important

� Keep the highest point vents in open position

during section emptying

� Reactor draining to be started after completion

of draining of Carbamate condenser. This is to

avoid bulging of reactor lining.

Page 11: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-311

Purging By N2 Of M.P. & L.P.Sections

� Purpose

� This operation must be carried out before

plant start-up in order to remove all the O2

present, avoiding any risk of explosive mixture

formation during ammonia charging.

Page 12: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-312

Purging By N2 - Conceptual Procedure

� Admit Nitrogen keeping the pressure controller in automatic mode.

� When N2 comes out from drain close block valves.

� Depressurize the system up to positive pressure of about 0.5 kg/cm2

� Analyze the gas outlet. If O2 content is 0.1% by vol. The purging is performed.

Page 13: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-313

Charging of Ammonia in MP Section

� Purpose

� To have a make-up of NH3 (Raw material)

� Pressurize the M.P.section

� Test H.P.NH3 pump

� Ammoniation

Page 14: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-314

Ammonia Solution Preparation in V-3

� Purpose

� Preparation of L.P.section to receive process

fluid

� The concentration of NH3 in V-3 solution is

about 30%

Page 15: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-315

Plant Heating Before Start Up

� Purpose

� Whenever start-up is to be performed with the unit emptyand at ambient temperature the equipment shall bepreviously heated in order to bring them to the bestconditions to feed the process fluids to the aboveequipment.

� This is to avoid:� Thermal stresses on the material

� Possibility of crystallization of products in cold piping and walls

Page 16: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-316

Plant Heating Before Start Up

� The section of High pressure synthesis shall be

heated up to the temperature of 150 ~ 160°C

before introducing the process fluids.

� Important

� The heating rate shall never exceed the values

recommended by the equipment manufacturers (~

30°C/hr)

Page 17: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-317

Conditions Before Ammoniation

� CO2 compressor ready to be started with high

pressure line heated up.

� Compressor will be put in running before

Ammoniation period.

� High pressure pumps ready to be started.

� High pressure section heated up and ready for

Ammoniation

Page 18: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-318

Conditions Before Ammoniation

� M.P. section charged and pressurized by ammonia with NH3

booster pump running in closed recycle to Ammoniareceiver.

� L.P. section charged with NH3 solution and M.P. carbonatesolution pump(P-3) running in circulation to Carbonatereceiver(V-3) through M.P. Absorber.

� Vacuum section ready to be taken in line.

� Prilling system ready to be started

� Waste water section in running condition.

Page 19: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-319

Ammoniation

Purpose

� To reach the best conditions to start the reactions

inside the reactor.

Conceptual procedure

� It consists in the pressurization of H.P.loop with

ammonia vapors up to 90 kg/cm2

� The “Ammoniation” operation requires about 3 hours

and then the unit can be fed by NH3 and CO2 to Urea

Reactor.

Page 20: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-320

Ammoniation

� The main steps are:

1. Start the pressurization of the Synthesissystem by sending NH3 via Ammonia booster(P-5) to Start-up line, leaving opened thesuction and delivery valves of H.P.Ammoniapump (P-1).the NH3 is vaporized in the jacketline.

2. Control that the NH3 vapor temp is over140°C.

Page 21: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-321

Ammoniation

3. When the H.P.system reaches the value of

Booster pump delivery pressure, start the

H.P.Ammonia pump(P-1) in recycle to

Ammonia Receiver (By opening the relevant

valves) and adjust the ammonia rate by

feeding a small flow to start-up line, so to

gradually increase the pressure of the system

up to about 90 kg/cm2g.

Page 22: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-322

Ammoniation

4. When the set value of pressure is reached (90kg/cm2),stop

NH3 feeding to Start-up line by closing the inlet valves and

simultaneously stop P1pump then proceed to close steam

to jacket of start-up line and wash this line by KW for a few

minutes.

5. The speed of pressure increasing on H.P.section (PIC-7)

has to be maintained at 30 kg/cm2 / hour to arrive at the

set of 90 kg/cm2g.

Page 23: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-323

Plant Preparation for Start Up(section by section)

� M.P. & L.P. section preparation

� Ammonia has been fed into NH3 receiver andboth sections (M.P. & L.P.section) arepressurized with ammonia vapors at 15kg/cm2g and 3 kg/cm2g respectively.

� MP carbonate solution pump (P-3) is runningwith a weak ammonia solution in recycle toCarbonate solution accumulator (via MPcondenser & MP absorber).

Page 24: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-324

Plant Preparation for Start Up(section by section)

� M.P. & L.P. section preparation

� To increase the ammonia content into thissolution, feed a small reflux flow to MPabsorber keeping the MP carbonate solutionpump (P-3) running in recycle.

� Stop the ammonia reflux to MP absorber (C-1)top only when the Carbonate solutionaccumulator analysis indicates an ammoniacontent of 35% by wt.

Page 25: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-325

Plant Preparation for Start Up(section by section)

� M.P. & L.P. section preparation

� Feed steam into shell sides of the M.P. andL.P.decomposers by opening the relevantcontrol valves of the 10 – 15 % and heat upthese equipment's by sending HW/LW at theinlet. Keep a level on the M.P. & L.P.decomposer holders.

� Put the steam tracing in service in all theprocess lines.

Page 26: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-326

Plant Preparation for Start Up(section by section)

� Vacuum evaporation section

� The evaporation section is to be put in water

recirculation to the urea solution tank via

vacuum concentrator/separator/urea solution

pump (P-8).

Page 27: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-327

Plant Preparation for Start Up(section by section)

� Process water treatment section

� The process water treatment section is running

water that from distillation tower (C-2)

Page 28: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-328

Plant Preparation for Start Up(section by section)

� CO2 compressor and passivation air system

� Start and load the CO2 compressor and stabilize it

venting the CO2 to the atmosphere from final

discharge vent (pressure control valve) in auto.

� Open the passivation air flow and put in service

the O2 analyzer.

Page 29: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-329

Initial Start Up (Feed in)

� Following action to be taken for Feed in

– Send condensate to Reactor for 10 minutes.

– Feed NH3 for about 15 minutes.

– Feed CO2 to Reactor

– Feed Carbamate at Reactor overflow

– Start passivation air injection (K-3)

– Parameter stabilization and production started

Page 30: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-330

NH3 and CO2 Feed in

� Send condensate to

– Reactor (R-1)

– Carbamate condenser (E-5)

� for about 10 minutes by means of H.P. flushing pump (KW

injection points) and after that close the valves and close

HV1(CO2 to R1).

� The NH3 present in the Reactor dissolves in the water

releasing heat and causing a temperature increase at the

Reactor bottom.

Page 31: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-331

NH3 and CO2 Feed in

� When the NH3 & H2O solution reaches the saturation and

this is shown by Reactor bottom temperature that stops to

increase (After about 10 minutes), proceed to open block

valve and motorized valve on NH3 discharge line and close

Carbonate recycle valve from H.P. Separator.

� Then start feeding Ammonia to the Reactor. The NH3

feeding flow rate must be about 50 rpm of P-1 ammonia

feed pump.

Page 32: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-332

NH3 and CO2 Feed in

� After about 10 minutes from introduction of

NH3,proceed to open the valves on CO2 to Reactor,

controlling the reactor bottom temperature.

� Before feeding CO2 to Reactor, be sure to inject the

passivation air in CO2 stream

Page 33: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-333

NH3 and CO2 Feed in

� At the overflow (after about 2 hours since reactor

feed in) of the reactor,

– open Carbamate recycle valve HV-2 from H.P. Separator,

– start sending the H.P.Carbamate solution to the

Carbamate condenser by opening the relevant valves

(HV-6).

– Monitor pump amperage

� (pump P-2 already running in circulation to C-1).

Page 34: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-334

NH3 and CO2 Feed in

� At reactor overflow,

� start opening the motorized valve (HV-5) at Stripper outlet line and regulate the stripper level controller (LV-2) in Manual mode.

� On manual mode adjust the opening of the MS steam pressure control valve (PV-14) admitting steam to shell side of Stripper, checking that the bottom temperature never exceeds 207°C.

Page 35: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-335

NH3 and CO2 Feed in

� The bottom pressure and temperature of reactor

shall be increased and maintained at about 179°C

and 155~160 kg/cm2. respectively.

� As a corrective action the flow rates of NH3 and CO2

can be reduced or increased in order to adjust

temperature and pressure of reactor.

Page 36: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-336

NH3 and CO2 Feed in

� Temperature increase:

– The NH3/CO2 ratio is decreasing, with consequent

pressure reduction in the system, it is necessary to

increase NH3.

� Temperature decrease:

– The NH3/CO2 ratio is increasing, the pressure will

tend to rise, it is necessary to decrease NH3 or

increase CO2.

Page 37: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-337

NH3 and CO2 Feed in

� As a guide, the weight ratio NH3/CO2 to

reactor should be around 1.15~1.2 during this

phase.

� The M.P. section is going to receive urea

solution.

Page 38: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-338

M.P./L.P. sections going to receive urea solution

� As soon as urea from R-1 enters the E-1, a decreasein steam pressure in the shell will be noticed.Adjust the MS flow to E-1 according to E-1 bottomtemperature.

� Feed Carbamate to R-1

� Urea solution from E-1 bottom passes to MPdecomposer, then to LP decomposer and initiallyto V-5 ( after stabilization, passes to vacuumsection).

Page 39: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-339

� Slightly open manually FV-102 sending NH3 to thetop of the C-1 and keep recirculation of carbonatesolution from V-3 to C-1 controlling bottom leveland temperature.

� Send condensate to top of C-3 so as to absorb NH3

present in the inert gas when level is establishedat the E-11 bottom start P-7 and send sol. to C-1and control the level.

M.P./L.P. sections going to receive urea solution

Page 40: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-340

� Maintain MP/ LP urea holder temperature

� Maintain MP /LP section pressure By putting PIC-

108 / PIC-133 on auto mode

� Pre concentrator level and start the pump

Preconcentrator pump(P-50) and ww water

pump(P-52).Vacuum ejectors also to be taken in

line

M.P./L.P. sections going to receive urea solution

Page 41: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-341

NH3 and CO2 Feed in

H.P. loop heating (including hot

bolting)5 to 8 hours

Condensate draining before

pressurization½ hour

Pressurization with NH3 Via start

up line3½ hours

NH3 and CO2 to reactor until

overflow occurs2 to 3 hours

Stabilization of running condition 1 hour

Page 42: Operation of urea fertilizers plant

UREA REACTOR AND HP SEPERATOR

Page 43: Operation of urea fertilizers plant

STRIPPER AND HP CONDENSER

Page 44: Operation of urea fertilizers plant

AMMONIA START UP LINE

HIC4

Page 45: Operation of urea fertilizers plant

MP DECOMPOSER & AMMONIA ABSORBER

Page 46: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-346

Page 47: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3

Page 48: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-348

Page 49: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-349

Page 50: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-350

Page 51: Operation of urea fertilizers plant

AMMONIA RECEIVER

Page 52: Operation of urea fertilizers plant

LP SECTION

Page 53: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-353

Shut Down

� Flushing

� Short shut down

� Long shut down

� Emergency shutdown

Page 54: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-354

Flushing system

� Urea plant shutdown main hazard is choking

� First and foremost priority is proper flushing

of the lines and vessels.

� There are three tier flushing system

– High pressure system

– Medium pressure system

– Low pressure system

Page 55: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-355

HP Flushing system

� Pump is a reciprocating one (P-11). It takes suction

from medium pressure pump discharge and

discharge water to different high pressure loop

washing point.

� Before starting KW washing, the pump discharge

pressure has to be set at 30Kg/cm2 more than that

of high pressure loop pressure.

Page 56: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-356

HP Flushing system

� Before injecting flushing water confirm V-2 temp>60-70oC and drain the water first to make theflowing water hot.

� Close the drain tightly and inject water.

� Check the KW pressure.

� Check if pressure has dropped or not. If pressurehas dropped that means line is clear.

Page 57: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-357

HP Flushing system

� If pressure has not dropped it means flushing hasnot taken place.

� De-choke the line immediately and then do theflushing.

� During HP loop flushing remember one thing

– Do not open water simultaneously at numerous points.

– Do flushing at one point at a time.

Page 58: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-358

MP Flushing system

� Pressure 36 kg.cm2 – a centrifugal pump(P-6).

� Water goes to :

– MP section,

– PV-07A D/S pipe

– HV-05 D/S pipe

– P-3 discharge

– P-2 suction

– P-8 discharge

Page 59: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-359

LP Flushing system

� Normally low pressure flushing pump (P-10) is

always in line. it is a centrifugal pump with

discharge pressure 15 kg/cm2.

� Water goes to:

– LP section, Vacuum section, C-2 and LTs’ flushing.

� Remember P-8 discharge is having MP flushing.

Page 60: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-360

Plant shutdown

1. Short shutdown means:– HP loop hold up.

2. Long shutdown means:– Necessitating HP loop draining.

3. Emergency shutdown– Due to power failure.

– Due to cooling water failure.

– Due to instrument air failure.

– Due to steam failure.

Page 61: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-361

Short Shutdown Procedure

� As soon as CO2 compressor trips HV-1 gets closed.PV-03 gets open. Close HV-08 and its I/V.

� If P-1 pump has not tripped, give Ammonia to Reactor for10 minutes then stop P-1.

� Close HV-7 and I/V after P-1 has stopped.

� Close 2nd discharge valve of P-1A or B (which ever is inline).

� Close HV-2.

� Stop P-2 (Carbamate pump).

� Close HV-6 & its I/V. Open FV-34.

Page 62: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-362

Short Shutdown Procedure

� Close PV-7A (if pressure is not getting hold, closeits I/V ).

� Close LV-02 & HV-05 after bringing down stripperlevel to minimum.

� Increase HV-03 opening.

� Check P-10, P-6, P-11 (flushing pumps) arerunning.

– P-11 discharge pressure 170Kg/cm2.

Page 63: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-363

Short Shutdown Procedure

� Divert prilling to V-5 via HV-132.immediatelyafter feed cut .

� Open PIC-140 & 141 first & second vacuumpressure control valves.

� Divert ME-3 to E-14 (HV-140) towards V-5.

� Open LP flushing water at E-14 inlet.

� Open HW at P-8 discharge to displace the Ureasolution in the vertical line.

Page 64: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-364

Short Shutdown Procedure

� Run P-8 on water for at least 5min. on load.

� Be careful enough so that LV-138 at P-8 discharge

should not get closed fully.

� P-8 discharge is not having any NRV so that hold

up solution in the vertical line gets drained to MV-7

easily if LV-138 is open.

Page 65: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-365

Short Shutdown Procedure

� Close ME-2 level control valve after ME-2 level is minimum.

� Check C-1 level. If required drain to V-3 via HV-102. Close

LIC-102.

� Reduce pure Ammonia reflux to C-1 according to the temp.

of C-1 top.

� Open P-3 recycle valve so that P-3 can have enough recycle

flow as auto recycle valve is not there.

Page 66: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-366

Short Shutdown Procedure

� Wash CO2 line towards reactor. Check KW pressure has

reduced to confirm flushing.

� Check physically that HV-1 has opened in field during

flushing.

� Flush ammonia line D/S of HV-7 to reactor.

� Flush HV-2 up stream & down stream.

� Flush LV-2 towards E-1 through the flushing line between

LV-2 & HV-5. Then flush through HV-5 by closing LV-2.

Page 67: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-367

Short Shutdown Procedure

� Flush PV-07A open KW between I/V & control valve.

� Flush towards MV-1 then flush through PV-7A by closingisolation valve & opening PV-7A.

� After flushing close PV-7A control valve.

� Flush HV-6 towards E-5 (Carbamate condenser) by openingisolation valve of HV06.

� Flush P-2 discharge line down stream of NRV with KW.First flush through FV-34 then close FV-34. Let the line getpressurized open HV-6 check pressure has come down toconfirm flushing to E-5.

Page 68: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-368

Short Shutdown Procedure

� Open HW (MP flushing water) to LV-101 up stream & down stream.

� Open HW to MV-2 from HV-5 D/S.

� Open HW to PV-7A D/S.

� Open HW in P-3 discharge & flush through LIC-102 to E-7.

� Flush HIC-102 line if C-1 draining is over.

� Open LW (LP flushing water) through ME-3 down stream line to V-5.

� Open HW in C-1 to P-2 line.

� Flush P-2 (Carbamate pump) from suction thoroughly. Check in opendrain that water is clear of Carbamate.

Page 69: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-369

Short Shutdown Procedure

� Flush and fill MV-8 (CO2 discharge drum) thoroughly after de-pressurizing vessel.

� Reduce the steam to stripper, MP & LP decomposer.

� Close PV-14, TIC-102 & its by-pass, TIC-131 & LV-03.

� Shut the reflux to C-1.

� Stop condensate to C-3 & C-4.

� Stop P-7 after E-11 level is minimum.

Page 70: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-370

Short Shutdown Procedure

PLEASE REMEMBER :

� Open KW only one point at a time.

� Confirm KW flushing by checking reduction in KWpressure.

� Close the process isolation valve first & then thewater injection valve.

� HW & LW can be opened at various pointsimultaneously.

Page 71: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-371

Long Shutdown Procedure (HP loop draining)

� IF SHUTDOWN IS PRE-PLANNED

– CHECK R-1 DRAIN LINE PRIOR TO FEED CUT.

� Checking of R-1 drain line� Check KW pressure is about 180Kg/cm2.

� Inject KW through R-1 drain line injection towards HV-4.

� Be careful that R-1 open drain & close drain valves are tightly closed.

� Open HV-4 & let KW to flow through HV-4 & HV-5 towards MV-2.

� Check KW pressure has dropped to about 50Kg/cm2 to confirm drainline is clear.

Page 72: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-372

Long Shutdown Procedure (HP loop draining)

� If pressure has not dropped, line is in choked condition.

� Do external steam heating U/S of HV-4.

� Do pressurization & de-pressurization of line up to HV-4

repeatedly by keeping HV-4 close.

� Check again if drain line has got cleared in the previous

method.

� If drain line is clear, start reactor draining.

Page 73: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-373

Long Shutdown Procedure (HP loop draining)

� Keep the following valves conditions as follows;

� I/Vs of HV-6,HV-7and HV-8 close

� LV-2 close.

� HV-2 close

� LV-3 ~10% open.

� I/V of HV-102 open.

� PV-7A I/V close.

� HV-140 and its I/V open.

Page 74: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-374

Long Shutdown Procedure (HP loop draining)

� Open Reactor drain I/V towards HV-4.

� Open HV-4 & HV-5.

� Open HV-1 (HV-1 inter lock to be by-passed from I-

1 on ESD)

� Feel the sound of flow.

Page 75: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-375

Long Shutdown Procedure (HP loop draining)

� Check level has come in ME-2 in Control Room &

physically in side glass.

� Control the Reactor draining rate to MP section

using HIC-4 & HIC-1.

Page 76: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-376

Long Shutdown Procedure (HP loop draining)

� Maintain Ammonia reflux to C-1 from P-5 to

maintain C-1 temperature.

� Maintain E-7 outlet temp. with LIC-102 minimum

30% open & with TIC-101 on auto.

� Maintain C-1 level by draining through HIC-102

to V-3.

Page 77: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-377

Long Shutdown Procedure (HP loop draining)

� Use greater amount of steam to E-2 without over

loading C-1 so that to recover a greater amount of

Ammonia to V-1.

� Check pressure drop is at a rate not more than

30Kg/cm2 per hour.

Page 78: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-378

� The temperature and pressure decline in the

synthesis system is controlled by adjusting the

reactor drain rate. The adjustment is made with

HIC-4 on manual control.

Long Shutdown Procedure (HP loop draining)

Page 79: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-379

� Check the temperature in the low pressure

decomposer in view of getting the maximum

concentration of urea solution and avoiding and

excessive quantity of ammonia being delivered to

the vacuum concentration system.

Long Shutdown Procedure (HP loop draining)

Page 80: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-380

Long Shutdown Procedure (HP loop draining)

� When no solution is coming out from reactor at a pressure

of about ~40Kg/cm2 drain Carbamate condenser to MV-2

through HV-4.

� Open HIC-2 and drain MV-1 to MV-2 thru’ HV-4

� After feed cut and before depressurization of HP loop close

air to reactor weep holes

� Confirm that draining is over, when LV-101 & LV-131 gets

almost closed.

Page 81: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-381

Long Shutdown Procedure (HP Loop Draining)

� When the synthesis loop pressure and the pressure of themedium pressure section are equal:

� Cut HP loop from MP by closing HV-1, HV-4, HV-5. and washall lines and equipment of the high pressure sectiondraining to the closed drain.

� Start depressurization of HP loop to BD header through PV-7B.

� Shut the steam to the decomposers, open the washing onthe outlet line bottom solution stripper, bottomdecomposer M.P. and L.P. and flush together with 2decomposers.

Page 82: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-382

Long Shutdown Procedure (HP loop draining)

� Close the delivery valve and stop P-3A/B.

� Stop NH3 at the top of C-1 by FIC-102 in manual

control.

Page 83: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-383

Long Shutdown Procedure (HP loop draining)

� Stop the ammonia booster pump and close the suction anddelivery valves.

� Send washing water to the top of C-1 for few minutes.

� Drain the liquid of the C-1 to the carbonate tank throughHV-102 when washing is finished. Shut off the water anddrain the column to the closed drain.

� Isolate the NH3 tank and absorber from the other mediumpressure equipment, leaving the pressure control inautomatic position.

Page 84: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-384

Long Shutdown Procedure (HP loop draining)

� Gradually depressurize the absorption column and the

medium pressure decomposer through LV-101.

� Take care not to pressurize the low pressure decomposer.

� Shut the steam to the decomposers E-3.

� Isolate the carbonate tank V-3 from C-1 leaving pressure

controller PRC-133 on auto.

� Dilute MP condenser E-7 and condenser E-11 solutions and

drain them out.

Page 85: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-385

Long Shutdown Procedure (HP loop draining)

� Stop the vacuum section circulation after MV-7 level comesto minimum & after confirming proper flushing and PIC-140 & 141 open.

� Stop flushing water to E-14 & other points.

� Cut steams to E-14 & E-15.

� Cut the condensate outlet to condensate tank.

� Cut steam to ejectors.

� Cut cooling water to condensers, if required.

� Stop V-9 transfer to V-6 by stopping P-21, if required.

Page 86: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-386

Long Shutdown Procedure (HP loop draining)

� After depressurization and close draining of HP loop is overopen LP steam to reactor for 3-4 hrs.

� Cut steam to reactor/HP loop.

� Open MP washing water to HP loop through 3” quick fillingline at reactor bottom with HV-1 open PV-7B open, HV-3sample point drain open and HV-2 close.

� Filling completion of reactor is indicated by water comingout from HV-3 sample point, close it.

� Filling completion of HP loop total is indicated by rise inPV-7B pressure.

Page 87: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-387

Long Shutdown Procedure (HP loop draining)

� If vessel man entry is to be permitted then overflow HPloop through PV-7B for 7-8 hrs. Other wise 3-4 hrsoverflow will do.

� Stop filling water, start draining HP loop from E-1 drain,from LV-2 sample point drain, from E-5 sample point drain& HV-3 sample point drain.

� When water stops coming out from HV-3 sample pointdrain, open reactor drain through HV-1 I/V gradually to fullopen condition.

� Total draining normally takes 8-10 hrs.

Page 88: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-388

Long Shutdown Procedure (HP loop draining)

� During HP loop draining, PV-7B should be open,HV-2 should be close.

� During filling of HP loop E-5 shell side should bedepressurized & drained to enhance cooling.

� Either steam circuit should be depressurized or alltracing / jacket steam should be closed andstripper shell side should be depressurized.

Page 89: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-389

Long Shutdown Procedure (HP loop draining)

� When water stops coming out from HV-3 sample

point reactor top manhole cover should be opened

to enhance draining & cooling.

� When water stops coming out from HV-3 sample

point, HV-3 may be handed over to maintenance, if

required.

Page 90: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-390

Long Shutdown Procedure (HP loop draining)

� When water stops coming out from E-5 or

E-1 bottom drains, E-5 or E-1 may be

handed over.

� During condensate draining smell the drain

water for ammonia to have an idea of

atmosphere inside HP loop vessels.

Page 91: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-391

EMERGENCY SHUT DOWN

� The emergency situations which are likely to arise

are several and extremely variable as to duration

and seriousness.

Page 92: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-392

EMERGENCY SHUT DOWN

� Principal causes:

1. Process reasons:

� Considerable pressure and / or temperature increases

� Pipe line clogging because of crystallization

2. Sudden failure of services

3. Fires, and / or ruptures with uncontrollable losses of

toxic gasses.

Page 93: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-393

EMERGENCY SHUT DOWN Safety interlocks

� Based on the above emergency causes, an interlock

trip system has been provided for the protection of

personal and equipment initiating an automatic

shut down system

Page 94: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-394

EMERGENCY SHUT DOWN Safety interlocks

� For point No. 3 (if occur) push buttons are

provided on urea desk to stop the principal

machines. The valves which isolate the synthesis

loop & NH3 to P-1will than be closed.

Page 95: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-395

� The evaluation of the seriousness of an emergency

situation and there fore the decision of how to shut

the plant down is a matter of the operators’

experience. He should take prompt and corrective

action.

� However, the inter lock system is designed to

minimize the number of manual operations.

EMERGENCY SHUT DOWN

Page 96: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-396

� Should the point no. 1 occur lines and equipment

should be washed, the trip causes eliminated

EMERGENCY SHUT DOWN

Page 97: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-397

Electric Failure

� Should a total failure of electric power occur,

the CO2 compressor and all the pumps of the

unit will stop.

� In this case restart the plant, locally starting

up the machines not re-accelerated.

Page 98: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-398

Electric Failure

� If on the contrary, the power failure is more

than momentary, only the pumps of

emergency network will restart automatically.

But, in this case, the cooling water will be

missing and, as a consequence a pressure

increase will occur in the medium and low

pressure sections and vacuum will be lost in

the evaporation section.

Page 99: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-399

Electric Failure

� Then the plant must be stopped following theinstructions shown here under. Introducewashing water to the following points :

� Introduce washing water to the followingpoints :1. Inlet to the concentrator E-14.

2. Bottom outlet stripper and outlet of the medium and low pressure decomposers.

3. P-3A/B delivery line and C-1 trays.

Page 100: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3100

4. High pressure Carbamate pump suction and

delivery lines.

5. CO2 and NH3 lines to reactor Carbamate to

ejector HV-2 (up streams and down stream).

Electric Failure

Page 101: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3101

� Now proceed as described for normal

shutdown.

Electric Failure

Page 102: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3102

� The plant uses steam at 23 kg/cm2g in

stripper E-1.

� Failure of this service also involves the

failure of the condensate from the stripper

which feed the MP decomposer E-2 &

subsequently the Carbamate condensers

E-5.

Steam Failure

Page 103: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3103

� The main plant and the ammonical water

treatment section should be shutdown since

there will be no steam production at

4.5kg/cm2g.

Steam Failure

Page 104: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3104

� The main machines must immediately betripped :

1. CO2 compressor,

2. P-1A/B NH3pump, and

3. P-2A/B Carbamate pump.

� Column C-1 shall be recycled to V-3 anddiluted, sending water to P-3A/B deliveryline. Wash and dilute all lines of the highpressure section.

Steam Failure

Page 105: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3105

� Wash the medium and low pressure

decomposers outlet lines to avoid

crystallizations.

� Stop and dilute the vacuum evaporation

section following the procedure described

for normal shutdown.

Steam Failure

Page 106: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3106

� The plant is thus in a safe shutdown

condition and ready to restart following the

usual restarting procedure, in case of steam

failure and/or long plant shutdown, it is

necessary to further dilute the solution

contained in tanks and apparatuses

recovering it as soon as the steam

availability is assured.

Steam Failure

Page 107: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3107

Cooling Water Failure

� The plant equipment employing coolingwater. Principal users are:– CO2 compressor (inter-stage cooler)

– Condensers , coolers and the pump coolers.

� Lack of this service causes a pressureincreases in the medium and low pressuresystem for lack of condensation in therespective condensers and vacuum loss inthe vacuum evaporation section.

Page 108: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3108

Cooling Water Failure

� Proceed as follows :

– Open E-41,E-9,E-7 top cooling water vents

– Stop feeding to the reactor. Trip compressor,

P-1,P-2 and all the pumps except for the washing

pumps must be stopped.

– Close LV-2,HV-5 and closing the steam valve

(PV-14) to the stripper

Page 109: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3109

Cooling Water Failure

– Close the steam valve to the E-2,E-3,to both

vacuum evaporators and to the column C-2 and

the ejectors.

– Send washing water to the delivery line of P-3A/B

to the trays of column C-1 to the condensers E-11

and E-8 absorb NH3 thus reducing the pressure,

Now, proceed as described for short shutdown.

Page 110: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3110

Instrument Air Failure

� In case off instrument air failure, the control

valves assume such positions as to ensure

the plant safety without the immediate

intervention of the operators, who however,

must be will aware of the general view of

these positions.

Page 111: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3111

Instrument Air Failure

� As soon as the instrument air is lacking, the

operator must switch to manual control all

instruments on DCS at zero signal position.

So that, when air gets in again, the valves do

not move.

Page 112: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3112

Instrument Air Failure

� The synthesis loop gets blocked and

automatically is isolated from the rest of the

plant. Shutdown must be actuated following

the same procedure as That described for

the electric power failure.

Page 113: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3113

Important Checks

Communicate to the followings before S/D:

urea-I

Ammonia-II

Bagging

Check reverse rotation if any, for K-1.

Before shut down keep V-1, V-3 level at

minimum.

Page 114: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3114

Important Checks

Check both P-11 are available.

Keep P-11 running before feed cut.

Before shutdown R-1 drain line & E-5 drainlines to be checked for any choking, clearthese lines if found choked.

Before shutdown HIC-102 line to be checkedfor any choking, clear these lines if foundchoked

Page 115: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3115

Important Checks

After shutdown do proper flushing of HP, MP

& LP lines.

After S/D do proper flushing of vacuum

section with LW at E-14, P-8 circulation.

Confirm P-8 is taking load. Double confirm

vacuum section flushing.

Page 116: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3116

Important Checks

After feed cut and before depressurization of

HP loop close air to reactor weep holes.

Page 117: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3117

Important Checks

Keep close check on P-33 level.

Put a fire hose without coupling in R-1 drain

line. Closely monitor B/L analysis.

Isolate MV-8 and depressurize MV-8 after

compressor tripping. Flush MV-8.

Page 118: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3118

� Depressurize MP loop

– E-9 should be kept isolated from V-1.

– MV-2, E-7, C-1 & E-9 through 2” BD header on

C-1.

– HP loop should be kept isolated from MP loop.

– Steam / MP steam condensate should be cut to

E-2.

MP Loop Hand Over

Page 119: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3119

� After depressurization is complete start filling

water from bottom of vessels with C-1 BD

header valve open and also open vent

isolation valve on MV-2 vapor line open.

� When water starts coming out from MV-2

vent & C-1 BD header let the overflow

continue till the water gets almost clear of

ammonia or for 1-2 hrs.

MP Loop Hand Over

Page 120: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3120

� Then stop filling and start draining from all drain

points.

� BD vent and open to atmosphere vent should be

open during draining.

� After the draining is over the MP loop vessels barring

V-1, E-11 & C-3 can be handed over for opening to

maintenance.

� Cooling water to E-7 and E-9 should be cut only

after depressurization is completed.

MP Loop Hand Over

Page 121: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3121

� V-1 should be tightly isolated from rest MP

loop before MV-2 to E-9 depressurization.

� Continue vaporizing ammonia till P-5 is

taking load.

� Stop P-5 when V-1 is empty. Close P-5

discharge valve tightly.

V-1 Handing Over

Page 122: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3122

� E-11 cooling water should be open during

depressurization.

� Open close drain of V-1 & C-3/E-11.

� Simultaneously depressurize V-1, C-3/E-11

through PV-108 to BD header.

� When depressurization is completed, start

filling water to V-1, C-3/E-11.

V-1 Handing Over

Page 123: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3123

� PV-108 should be open full during filling.

� Allow the water to over flow through PV-108for some time.

� Stop filling, start draining through all drainsincluding P-5 suction strainer flange.

� After draining is completed, V-1& C-3/E-11can be handed over to maintenance foropening.

V-1 Handing Over

Page 124: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3124

� Keep V-3 level minimum before feed cut.

� After reactor draining through MP & LP is over, flushthe LP section thoroughly.

� Isolate V-3 from E-8(liquid & vapor line both) if V-3 isnot to be opened.

� Depressurize and drain ME-3-E-3-MV-3 & E-8completely through the open to atmosphere vent.

� Fill flush overflow & drain the system.

� During draining vent should be confirmed to be opento atmosphere.

L P Loop Handing Over

Page 125: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3125

E-1 Handing Over

� After filling and draining twice check for

ammonia in E-1 drain and skin temperature.

� While draining 2nd time give SWP to open

alternate bolts.

� If NH3 in the drain sample in too high further

fill E-1 only and drain it.

Page 126: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3126

E-1 Handing Over

� If NH3 is not there in drain sample give SWP

to open man holes HV-3, LV-2, E-1 LT

tapping /thermocouple are to be removed.

� Put DM water hose at the top after E-1 top &

bottom cover is opened.

� Put air hose at bottom through LV-2 after it

gets opened.

Page 127: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3127

� Slip plate E-1 vapor line to E-5 (8” flange).

� Check whether MV-4 has been

depressurized and drained.

E-1 Handing Over

Page 128: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3128

� For E-1 shell side pressure testing give SWPto blind following points, check steam circuitto MV-4 has been depressurized anddrained.

�MS steam inlet flange -10”.

�Condensate outlet flange to MV-4 -6”.

�MV-4 balance line- 2”.

�PSV-5 flange- 6”.

E-1 Handing Over

Page 129: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3129

� Check E-5 is isolated depressurized anddrained from shell side.

� After filling tube side and draining E-5second time with water check ammonia indrain sample.

� Check start-up line both E-1 side valvesclosed.

� E-1 vapor line to E-5 is also blinded.

E-5 Handing Over

Page 130: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3130

� Confirm first steam system is in

depressurized condition.

� Give SWP for blinds in following points.

1. Export condensate flange-4”

2. Import line NRV flange-2”

3. LG tapping – upper one LG auxiliaries should be

removed by instrumentation.

E-5 Handing Over

Page 131: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3131

4. Line from

1. MV-4 –6”

2. Steam outlet flange 2 no.-20”

5. PSV flanges

1. 2 no. –6”.

2. E-5 shell side drain one no. 3”

� Total 8 blinds. LT tapping 2no.

E-5 Handing Over

Page 132: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3132

Lower LG tapping flange should be

connected with a flanged ½” nipple with

isolation valve for air injection.

� Simultaneously give SWP to open E-5, ME-1

after confirming no ammonia in drain.

– E-5 manhole is to be opened.

– E-5 bottom and top flanges are to be gapped so

that air circulation can take place in E-5.

E-5 Handing Over

Page 133: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3133

� As soon as HV-1, HV-2 are opened put air

hose through the gap in the reactor.

� While giving SWP to open HV-1, HV-2 &

PRC-12.

R-1 Handing Over

Page 134: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3134

� Check –

1. R-1 open drains are in open condition.

2. R-1 CD are in closed position HV-4 close.

3. MV-8 is depressurized condition.

4. Confirm all the injections are closed.

5. Confirm P-11 is not running.

6. No water is coming out of HV-2 up streamdrain. Check HV-3 is removed

R-1 Handing Over

Page 135: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3135

7. P-1 to HV-7 is in depressurized and flushed

condition.

8. HV-7 isolation valve is in closed condition.

9. P-1 discharge valve is in closed condition.

10. PV-7A isolation valve is in closed condition.

R-1 Handing Over

Page 136: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3136

11. Tracing drains are open. Steam of circuit is

in depressurized condition.

12. Arrange to get R-1 top sample analyzed

with a blower and PVC piping arrangement.

R-1 Handing Over

Page 137: Operation of urea fertilizers plant

R-1E-1 MV-2 V-1 MV-3137

For any type of queries

Please contact to

Prem Baboo

Mob-+919425735974

+918718870316

[email protected]

[email protected]