NACE_Standard_Application_Example for Sulfuric Acid Storage

Presented to TX LA NACE Chapter

Presented by

Carl Matherne - Engineer, BASF Port Arthur

Application of NACE Standards for Sulfuric Acid Storage and Delivery – Tanks and Piping

June 15, 2010 – NACE

BASF FINA Petrochemicals Limited PartnershipBASF FINA Petrochemicals Limited Partnership

Background

93-98% Sulfuric Tank Storage and Delivery at Facility

Storage Capacity 2035 ft^3( 13,200 gallons)

Shell Construction 3/8(0.375)inch with 1/8(0.1875)inch corrosion allowance

Built in 1999


Background

Maintenance Issues

Storage tank observed numerous leaks

Venting of gas from roof vent common during loading

Accelerated corrosion band noted in tank during on stream monitoring of tank thickness

General area in disrepair

Operators regard area as hazardous

Numerous leaks reported annually

Tank identified for nozzle repair and clamp removal during turnaround and tank internal inspection


Findings

Tank entered for inspectionBand of corrosion verified at top of liquid to inert pad interface Pump recirculation or minimum flow nozzle severely corroded – noted for replacementPump suction nozzle corrosion erosion notedFloor scanned for integrity – nominal wall found


Damage Photo Findings – Min Flow Return (Clamped and Stainless Liner)


Damage Photo Findings – Shell Damage

0.100 INCH WALL LOSSES FOUND


Damage Photo Findings – Tank Fill Nozzle

DAMAGE TO HEAT AFFECTED ZONE


Damage Photo Findings – Pump Suction

0.110 INCH WALL LOSSES FOUND


Data Mining Results

Contacted Sulfuric Acid Vendor for RecommendationsRecommended NACE Standards– SP0294-2006(formerly RP0294-94) – Design,

Fabrication, and Inspection for Sulfuric at Ambient Temperatures

– RP0391-2001 – Materials for Sulfuric Acid

Received copies of suppliers specifications for different concentrations – corresponded to NACE recommendations

Contacted internal technical engineers

Recommended rule of reduced velocity <2 ft/sec Carbon


Tank Changes Made During Outage

Initiated Management of Change to change return and suction nozzles to conform to RP0294

Pump suction to change from 4" A-53-B to 4" SCH80 A20 SB464 Min flow recirculation line change from 2" sch 80 A-53-B to 2" sch 80 A20 SB464Modify recirculation line to direct flow to below tank liquid level using extension into tank at recirculation Add wear plate at pump suction and returnAdd positioning stabilizer to return line

Repairs as noted per API 653(API 650)Weld repairs to tank sumpWeld repairs to nozzle heat affected zones


Schematic of Recommended Design


Schematic of Nozzle Liners


Schematic of Suction Return Design


Schematic of Top Return Design


Field Modifications – Tank Return

RETURN LINE TOP PENETRATION INSERT


Field Modifications – Tank Suction Return

SUCTION RETURN MODIFICATION


Conclusion

Recommendations:

Check for applicable NACE standards

Check velocities of streams for materials

Monitor storage vessels with accelerated corrosion risk

Reference applicable standards

Contact material suppliers for recommendations


Questions

Thank you for your time!

NACE_Standard_Application_Example for Sulfuric Acid Storage

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