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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

Commissioning Experience of a Large Scale Ammonia Plant

Ma’aden Phosphate Company 1

CONTENTS

 Introduction to Ma’aden Phosphate Company  Project Highlights  Features of Ammonia Plant  Commissioning Experience  Conclusion

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MA’ADEN PHOSPHATE COMPANY  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 3

MA’ADEN PHOSPHATE COMPANY 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 4

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OVERVIEW OF THE INTEGRATED COMPLEX

BENEFICIATION PLANT

PHOSPHORIC ACID PLANT

SULFURIC ACID PLANT

DAP PLANT

AMMONIA PLANT 5

PROJECT HIGHLIGHTS Project Execution  Samsung Engineering Company contractor on LSTK basis

Limited

as

EPC

 Worley Parson as Project Management Consultant (PMC)  Uhde on advisory services to Samsung during project stage and for supply of the critical equipments  Project kick started with EDC in May 2007 and performance test completed in May 2011 6

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PROJECT MILESTONES Major Events Effective Date of Contract Basic Engineering Commencement Detailed Engineering Completion Mechanical Completion Lighting of Primary Reformer Natural Gas Feed Completion of LTS Catalyst Reduction Methanator Catalyst Reduction First Ammonia Production Trial Test |Completion & Achievement of 100% Load Completion of Performance Test

Date 28.05.2007 30.10.2007 26.05.2009 24.08.2010 29.12.2010 07.01.2011 24.01.2011 26.01.2011 11.02.2011 27.04.2011 03.05.2011

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PROJECT MILESTONES Consumption of Raw Materials & Utilities Description Energy Consumption Desalinated Water Sea Water (DT=10째C)

Unit Expected Figure 31.078 GJ/MT of NH3 M3/MT of NH3 0.884 3 M /MT of NH3 285.000

Performance Test Results Description Energy Consumption Nox (NO2) Level, Primary Reformer Stack (Maximum 150)

Unit Test Result GJ/MT of 28.283 NH3 Mg/Nm3

91.785

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AMMONIA PLANT LAYOUT

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FEATURES OF AMMONIA PLANT 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: One Hydotreater reactor and two ZnO Reactors working in lead/lag/parallel operation  Primary Reformer: Top fired box type furnace with 408 tubes in 8 rows/combustion air fan with dual drive, 189 burners (Low Nox)/Cold Outlet Manifold System 10

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FEATURES OF AMMONIA PLANT  Removal of CO2 by absorption with aMDEA solution  Synthesis Gas Drying Unit: Two MS adsorber vessels in parallel/ three filters in parallel/one regeneration gas heater  Ammonia Synthesis: Uhde Dual Pressure Process with Two Synthesis Sections Once through Synthesis @ 110.0 bar (Approximately 1000 MTPD) and Loop Synthesis @ 204.0 bar (Approximately 2300 MTPD)

Outlet Manifold System

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COMMISSIONING EXPERIENCE Leaks During Tightness Test for Primary Reformer Tubes  Pressure test of the system at 40 bar  340 flanges out of 408 had leaks  All gaskets replaced and less torque applied for tightening  During retesting, 102 flanges found to have leaks  All the gaskets replaced with torque of 300 Nm Thereafter, no more leaks were observed 12

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COMMISSIONING EXPERIENCE 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 13

COMMISSIONING EXPERIENCE 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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COMMISSIONING EXPERIENCE 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 essential All dead zones in the system to be included while rinsing

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COMMISSIONING EXPERIENCE Heavy Wear of Worm Gear for Turning Device The Worm Gears for the turning device of NG, SG, RF, PA Compressor Turbines and Generator Turbine were found to have undergone severe wear

MHI Experience (Wear)  Ferrite content to be <5% as excess ferrite causes reduction in wear resistance  Application of surface treatment by nitriding and lubricant coating of the hardened worm gear to reduce the friction force on the Overview and Damaged Condition of the Worm Gear sliding surface 16

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COMMISSIONING EXPERIENCE Heavy Wear of Worm Gear for Turning Device 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 17

COMMISSIONING EXPERIENCE Heavy Wear of Worm Gear for Turning Device 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 18

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COMMISSIONING EXPERIENCE Heavy Wear of Worm Gear for Turning Device 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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COMMISSIONING EXPERIENCE Heavy Wear of Worm Gear for Turning Device Recommendation Temporary 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 20

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COMMISSIONING EXPERIENCE HP Steam Superheater  HP steam superheater could not superheat saturated steam  Less heat only available in the convection box  The temperature of the HT shift converter was going up. Desulfurization Section temperature came down  It was decided to stop the plant and inspect the HP Superheater

HP Steam Superheater

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COMMISSIONING EXPERIENCE HP Steam Superheater

Steam Side Schematic of the Superheater

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COMMISSIONING EXPERIENCE 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

Cover Plate Lifted-up and Bent

 Gasket material found on top of tube sheet  Gasket blown-out and gap between shell and expansion bellow found increased

Sheared-off Bolts

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COMMISSIONING EXPERIENCE HP Steam Superheater 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 or synthesis gas waste heat boiler system  Accumulation and sudden evaporation of BFW from attemperators u/s convection bank  Improper installation of top cover after removing internal bypass during chemical 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 24

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COMMISSIONING EXPERIENCE HP Steam Superheater Analysis  During startup, no positive flow of steam through the super heater coil  Steam venting through the start up vent at the steam drum itself  Entry of water and sudden generation of steam exceeding the allowable pressure difference across the super heater

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COMMISSIONING EXPERIENCE HP Steam Superheater Modified Start Up Procedure  Gradual transfer of steam venting to start up vent downstream of the super heater establishing a positive flow of steam and not allowing any residual heat  Establishing adequate circulation in the WHB system through start up steam  Lining up block valves of attemperator only when the skin temperature of the coils reaches 480°C  Monitoring the differential pressure across the steam super heater during start up With this revised procedure, the plant was successfully started without any problem 26

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COMMISSIONING EXPERIENCE 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 27

COMMISSIONING EXPERIENCE Problem in Natural Gas Pressure Control System 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 28

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COMMISSIONING EXPERIENCE Problem in Natural Gas Pressure Control System 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 29

COMMISSIONING EXPERIENCE 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 30

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COMMISSIONING EXPERIENCE Impact of Fluctuation in NG Composition Impact 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 31

COMMISSIONING EXPERIENCE 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 32

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COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section

View of the Gap being Filled Between the Ceramic Modules Downstream of Transition Duct 33

COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section 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 34

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COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section

Transition Duct 35

COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section

Closeâ&#x20AC;?Up View of the Tunnel Bricks to Transition Duct

Connection of Tunnel Bricks to the 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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COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section

Connection of Tunnel Bricks to the Transition Duct Close-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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COMMISSIONING EXPERIENCE Hot Spot in Reformer Convection Section Action Taken  Steam sparger provided as a temporary solution  The permanent solution is to overcome the movement of the tunnel bricks during expansion and contraction of the furnace during plant upsets  Recommendations from Kareena and Uhde are awaited

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CONCLUSION  Commissioning of MPC’s Ammonia Plant was smooth  First production within 7 weeks from the time reformer was lighted and within 5 weeks after introduction of feedstock  Problems faced during commissioning of the plant handled successfully and the plant throughput increased to the rated capacity successfully  Having successfully stabilized the operations, MPC is embarking upon taking up the plant load further 39

Thank You 40

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