120218212552_4_1_maaden

18th AFA Int’l Annual Fertilizer Forum & Exhibition Feb., 7-9-2012,

Sharm El-Sheikh , Egypt Maritim Jolie Ville Hotel

Commissioning Experience of a Large Scale Ammonia Plant

Mr. Sayer Al-Mufadhali,

Staff Production Eng, Ma’aden Phosphate Co.

Saudi Arabia

2/18/2012

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CommissioningExperience ofaLargeScale

AmmoniaPlant

Ma’adenPhosphateCompany

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CONTENTS

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Introduction to Ma’aden Phosphate Company

Project Highlights

Features of Ammonia Plant

Commissioning Experience

Conclusion

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MA’ADEN PHOSPHATE COMPANY

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Joint venture between the Saudi Arabian Mining Company (Ma'aden) and Saudi Basic Industries Corporation (SABIC)

Fully integrated Phosphatic Fertilizer Complex based on phosphate deposits at Al Jalamid to manufacture Diammonium Phosphate

Natural gas and Sulfur from ARAMCO

Al Jalamid mine in the north of the Kingdom comprises of a phosphate mine and a beneficiation plant

The phosphate concentrate transported by rail to Ras Al Khair through a distance of 1400 KMs

Ras Al Khair on the eastern coast of the Arabian Gulf 130 km north of Jubail has Ammonia, Sulfuric Acid, Phosphoric Acid and DAP plants

Ras Al Khair also has exclusive port facilities to export Ammonia and DAP

MA’ADEN PHOSPHATE COMPANY

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Production capacities at Ras Al Khair are as follows:

Ammonia: 3300 TPD

Sulfuric Acid: 3 streams each of 4500 TPD

Phosphoric Acid: 3 streams each of 1460 TPD

DAP: 4 streams each of 2250 TPD

Power Generation: 150 MW

Desalinated Water: 40000 M3/Day

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OVERVIEW OF THE INTEGRATED COMPLEX

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BENEFICIATION PLANT

PHOSPHORIC ACID PLANT

SULFURIC ACID PLANT

DAP PLANT

AMMONIA PLANT

PROJECT HIGHLIGHTS

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Project Execution

Samsung Engineering Company Limited as EPCcontractor on LSTK basis

Worley Parson as Project Management Consultant(PMC)

Uhde on advisory services to Samsung during projectstage and for supply of the critical equipments

Project kick started with EDC in May 2007 andperformance test completed in May 2011

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PROJECT MILESTONES

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Major Events Date Effective Date of Contract 28.05.2007Basic Engineering Commencement 30.10.2007Detailed Engineering Completion 26.05.2009Mechanical Completion 24.08.2010Lighting of Primary Reformer 29.12.2010Natural Gas Feed 07.01.2011Completion of LTS Catalyst Reduction 24.01.2011Methanator Catalyst Reduction 26.01.2011First Ammonia Production 11.02.2011Trial Test |Completion & Achievement of 100% Load 27.04.2011Completion of Performance Test 03.05.2011

PROJECT MILESTONES

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Performance Test Results

Consumption of Raw Materials & Utilities

Description Unit Expected FigureEnergy Consumption GJ/MT of NH3 31.078

Desalinated Water M3/MT of NH3 0.884Sea Water (DT=10°C) M3/MT of NH3 285.000

Description Unit Test Result

Energy ConsumptionGJ/MT of

NH328.283

Nox (NO2) Level, Primary Reformer Stack (Maximum 150)

Mg/Nm3 91.785

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AMMONIA PLANT LAYOUT

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FEATURES OF AMMONIA PLANT

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The Ammonia Plant is based on Uhde Standard Dual Pressure Concept (USDPC) process to produce 3,300 MT/day of anhydrous Ammonia in a single stream with purity of 99.8 % (min)

Desulfurization Unit: OneHydotreater reactor and twoZnO Reactors working inlead/lag/parallel operation

Primary Reformer: Top firedbox type furnace with 408tubes in 8 rows/combustionair fan with dual drive, 189burners (Low Nox)/ColdOutlet Manifold System

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FEATURES OF AMMONIA PLANT

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Removal of CO2 by absorption withaMDEA solution

Synthesis Gas Drying Unit: TwoMS adsorber vessels in parallel/three filters in parallel/oneregeneration gas heater

Ammonia Synthesis: Uhde DualPressure Process with TwoSynthesis SectionsOnce through Synthesis @ 110.0bar (Approximately 1000 MTPD)and Loop Synthesis @ 204.0 bar(Approximately 2300 MTPD)

Outlet Manifold System

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Leaks During Tightness Test for Primary Reformer Tubes

Pressure test of thesystem at 40 bar

340 flanges out of 408had leaks

All gaskets replacedand less torque appliedfor tightening

During retesting, 102flanges found to haveleaks

All the gaskets replacedwith torque of 300 NmThereafter, no moreleaks were observed

COMMISSIONING EXPERIENCE

2/18/2012

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Leaks During Tightness Test for Primary Reformer Tubes

Conclusion Excess torque resulted in gasket inner ring damage and bending of

outer ring 300-350 Nm found to give the required torque for tightness without leak


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Damage to Demisters in the Steam Drum

During chemical cleaning, demisters were removed and reinstalled

System pressurized by steam to 50 barg to test the integrity

When opened for preparation of alkali boil out, 7 out of 13 demisters were found damaged Damaged Drum Demister

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Damage to the Demisters in Steam Drum

Analysis Chemical cleaning had four

stages of cleaning namely degreasing, acid pickling, neutralization and passivation

HCl used to correct the pH of the contents in the holding tank of the system

Migration of residual chlorides from the steam header during pressure test

The damage to the demisters caused by Chloride Stress Corrosion Cracking

Conclusion: Thorough rinsing essentialAll dead zones in the system to beincluded while rinsing


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Heavy Wear of Worm Gear for Turning Device

The Worm Gears for the turning deviceof NG, SG, RF, PA CompressorTurbines and Generator Turbine werefound to have undergone severe wear

Overview and Damaged Condition of the Worm Gear

MHI Experience (Wear) Ferrite content to be <5% as

excess ferrite causes reduction inwear resistance

Application of surface treatmentby nitriding and lubricant coatingof the hardened worm gear toreduce the friction force on thesliding surface

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Possible Causes

Oil supply

Oil supply temperature, pressure and quality

Turning torque

Teeth contact of worm gear

Turning motor electric current

Worm gear strength

Hardness and ferrite content



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Results Oil supply check found to be satisfactory

Oil Supply temperature, pressure and quality within acceptable limits

No heavy contact of internal parts as manual turning can be done

Actual current of turning gear higher than expected for SG Compressor turbine. Rated current is 2.90A versus measured current of 2.75A

Worm gear strength found to be satisfactory

Hardness and ferrite content found to be satisfactory


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Conclusion

The actual required turning torque was above the design because of unknown condition due to increase in internal friction force

Hence, the existing worm gear has less safety margin for wear resistance

MHI to offer improved material


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RecommendationTemporary Action (Material change of worm gear)

MHI have two materials for worm gears (Cast Iron & Copper Based Alloy) The wear resistance of copper alloy is higher than cast iron Recommended to replace cast iron type with copper alloy type

Permanent Action

The existing worm gear does not have sufficient wear resistance against unknown operating condition MHI is looking to introduce a new wear resistant material



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HP Steam Superheater

HP steam superheater could notsuperheat saturated steam

Less heat only available in theconvection box

The temperature of the HT shiftconverter was going up.Desulfurization Sectiontemperature came down

It was decided to stop the plantand inspect the HP Superheater



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Steam Side Schematic of the Superheater

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HP Steam Superheater Observations

Cover plate of shroud dividing saturated steam inlet from superheated steam outlet found lifted and bent

All 32 bolts holding the cover plate on top of the shroud found sheared off. The material of 4 of the 32 bolts found to be different

Gasket material found on top of tube sheet

Gasket blown-out and gap between shell and expansion bellow found increased

Cover Plate Lifted-up and Bent

Sheared-off Bolts


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Possible Causes

Possible damage during steam blowing through internals

Improper operation of plant during start-up/shut-down

Carry-over to HP steam super heater either from steam drum orsynthesis gas waste heat boiler system

Accumulation and sudden evaporation of BFW from attemperators u/sconvection bank

Improper installation of top cover after removing internal bypass duringchemical cleaning and steam blowing during pre-commissioning

Improper tightening of bolts/wrong bolt material

Improper tack welding of nuts leading to high stress of bolts

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Analysis During startup, no positive flow of steam through the super

heater coil

Steam venting through the start up vent at the steam drumitself

Entry of water and sudden generation of steam exceedingthe allowable pressure difference across the super heater


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HP Steam SuperheaterModified Start Up Procedure

Gradual transfer of steam venting to start up vent downstream of thesuper heater establishing a positive flow of steam and not allowing anyresidual heat

Establishing adequate circulation in the WHB system through start upsteam

Lining up block valves of attemperator only when the skin temperature ofthe coils reaches 480°C

Monitoring the differential pressure across the steam super heaterduring start up

With this revised procedure, the plant was successfully startedwithout any problem

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Problem in Natural Gas Pressure Control System

Shutdown due to failure in managing two control valves in parallel in natural gas line

The 16” butterfly valve suddenly closed to “full close position” and the plant tripped

On another occasion, the valve suddenly started opening and closing repeatedly causing severe hunting of flow and plant tripping

In both cases, 16” butterfly valve was in auto mode and NG pressure at battery limit suddenly started hunting in a very unstable manner

Observations

There were common conditions on both occasion

Upstream pressure gone to 40 barg

Downstream pressure was 20 barg and there was a sudden surge of 3~4 bar

Controller command forced the valve to be fully closed within one minute


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Possible Reason for Sudden Pressure surge

Pressure surges appeared when the upstream pressure was 40 barg and downstream pressure was around 20 barg

Differential pressure across the valve became greater than the critical pressure ratio possibly making shock waves downstream near the throat of the valve

When there is a high pressure drop across the valve (P up/P down >1.8), the flow characteristic through the valve are changed from sub-sonic flow to sonic (choked) flow

This supersonic flow in turn could generate shock waves downstream of the throat (valve) forming a localized pressure build-up

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Conclusion

Localized shock waves due to high delta pressure could be the reason

Not recommended to have aggressive action of the valve especially choked flow condition. The proportional band adjusted

Decided to keep the 16” Butterfly control valve on manual with constant opening and to keep the 6” Globe valve on auto to take care of pressure fluctuations


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Impact of Fluctuation in NG Composition

Changes in gas composition at times very rapid

Could lead to plant trip sometimes

Observations Since plant commissioning,

varying composition of gas has been observed

Natural gas generally heavier Heavier hydro-carbons showing

heavy fluctuations within short span of time in the composition

Natural Gas Composition

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Impact of Fluctuation in NG CompositionImpact on Process

Process steam flow adjusted to maintain overall steam-carbon ratio of 3.0

High fluctuations and high carbon number in feed gas composition results in additional load on CO2 removal unit leading to higher CO2

slip

Action Taken

Close monitoring of plant parameters during fluctuations by adjustment of gas flow rate and/or process steam flow rate

Regular interaction between MPC and supplier to improve the natural gas quality and advance communication when there is any change in natural gas compositions


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Hot Spot in Reformer Convection Section

Sequence of Events

Hot spot observed downstream of the Transition Duct

During a shutdown opportunity, the convection bank was opened and inspected

Gap observed between the ceramic fiber modules on the top and east side

Gap filled with ceramic fiber

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View of the Gap being Filled Between the Ceramic Modules Downstream of Transition Duct


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Sequence of Events During inspection, gaps were also observed upstream of the

transition duct where the connection of the tunnel bricks exists with the ceramic fiber modules and in particular the castable lining behind the tunnel bricks

New fiber blankets fitted into the gaps and the tunnel bricks moved back into position

After a period of few months, hot spots observed upstream of the transition duct along the entire length

Channeling of hot gases through the gaps generated these hot spots

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Transition Duct


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ConnectionofTunnelBrickstotheTransitionDuct

Close‐UpViewoftheTunnelBrickstoTransition Duct

Gaps Observed Between the Tunnel Bricks & Transition Duct Modules

View of the Cast Lining between the Tunnel Bricks and Insulation Modules

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Connection of Tunnel Bricks to the Transition DuctClose-Up View of the Tunnel Bricks to Transition Duct

Gaps Observed Between the Tunnel Bricks & Transition Duct Modules

View of the Cast Lining between the Tunnel Bricks and Insulation Modules


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Action Taken

Steam sparger provided as a temporary solution

The permanent solution is to overcome the movement ofthe tunnel bricks during expansion and contraction of thefurnace during plant upsets

Recommendations from Kareena and Uhde are awaited

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CONCLUSION

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Commissioning of MPC’s Ammonia Plant was smooth

First production within 7 weeks from the time reformer waslighted and within 5 weeks after introduction of feedstock

Problems faced during commissioning of the plant handledsuccessfully and the plant throughput increased to therated capacity successfully

Having successfully stabilized the operations, MPC isembarking upon taking up the plant load further

Thank You40

120218212552_4_1_maaden

Documents

ammonia production

ammonia plant layout

phosphate deposits

large scale ammonia

mtday of anhydrous ammonia

kms ras al khair

tpd phosphoric acid

tpd sulfuric acid