Sulfuric Acid Storage Tanks

A brief history of SATCO’s tank failures and repairs.

Terminal OverviewTerminal Overview

• Three tanks built in 1979 by GATX CorpThree tanks built in 1979 by GATX Corp. for Texas Gulf Sulfur.

• Tanks are pile supported with an elevated• Tanks are pile supported with an elevated concrete pile cap and 3” sand cushion.T i l ti d i d t• Terminal operations were designed to receive by vessel and ship out by truck.

• In 1989 the terminal was purchased and converted to sulfuric acid.

Conversion from Molten SulfurConversion from Molten Sulfur

• Tanks were cleaned of sulfurTanks were cleaned of sulfur• Steam & condensate lines were cut and

capped on outside of tankcapped on outside of tank.• Vessel discharge lines relocated to roof.• Tanks were converted in this manner as

an option to return to sulfur service.

November 2001 Tank 3 LeakNovember 2001 Tank 3 Leak

• A small trickle of acid was discoveredA small trickle of acid was discovered coming from between the floor and the concrete pile capconcrete pile cap.

• Tank was evacuated, cleaned, and neutralizedneutralized.

• Location of the leak was determined.• Cause of the leak was determined.

Underside of tank 3 floorUnderside of tank 3 floor

November 2001 Tank 3 RepairsNovember 2001 Tank 3 Repairs

• Insulation was removed from shell & roof.Insulation was removed from shell & roof.• Steam & condensate lines were removed.• Roof support columns were purgedRoof support columns were purged.• New ⅝” carbon steel butt-welded floor w/backing

bars installedbars installed.• New ¼” carbon steel lap-welded roof installed.• New 10” SCH80 carbon steel nozzle installed• New 10 SCH80 carbon steel nozzle installed.• Construction was repeated for tanks 1 & 2.

November 2008 Tank 2 LeakNovember 2008 Tank 2 Leak

• A small trickle of acid was discoveredA small trickle of acid was discovered coming from between the floor and the concrete pile capconcrete pile cap.

• Tank was evacuated, cleaned, and neutralizedneutralized.

• Location of the leak was determined.• Cause of the leak was determined.

Recovery of acidRecovery of acid

Pin hole in t-joint weldPin hole in t joint weld

November 2008 Tank 2 RepairsNovember 2008 Tank 2 Repairs

• T-Joint was arc gouged 12” in eachT Joint was arc gouged 12 in each direction, re-welded, & tested per API 653.

• Shear wave testing was performed on• Shear wave testing was performed on 25% of remaining t-joints.F ll API 653 t f i i ti• Full API 653 out of service inspection performed.

• Tank was returned to service.

Slag inclusions & cracksSlag inclusions & cracks

January 2009 Tank 2 LeakJanuary 2009 Tank 2 Leak

• A small trickle of acid was discoveredA small trickle of acid was discovered coming from between the floor and the concrete pile capconcrete pile cap.

• Tank was evacuated, cleaned, and neutralizedneutralized.

• Location of the leak was determined.• Cause of the leak was determined.• Extensive NDE performed on floor welds.p

½” crack in t-joint weld½ crack in t joint weld

FMT of t-joint crackFMT of t joint crack

Slag InclusionsSlag Inclusions

Backing bar not attachedBacking bar not attached

Slag InclusionsSlag Inclusions

January 2009 Tank 2 RepairsJanuary 2009 Tank 2 Repairs

• New ⅝” carbon steel butt-welded floorNew ⅝ carbon steel butt welded floor w/backing bars installed.

• New 8” SCH80 roof columns installed• New 8 SCH80 roof columns installed.• New 10” SCH80 low/high suction nozzle

t t t API t d darrangement to meet API standards.

New High/Low Suction NozzlesNew High/Low Suction Nozzles

What went wrong in 2002What went wrong in 2002

• State of Florida licensed engineer wasState of Florida licensed engineer was hired to design repairs, bid jobs, and oversee constructionoversee construction.

• All required NDE was performed.N CWI d• No CWI used

What should be doneWhat should be done

• Tank contractor submits constructionTank contractor submits construction procedures, mill test reports (MTR), welding procedure specifications (WPS), g p p ( )procedure qualification records (PQR), and individual welder certifications for

lapproval.• Certified Welding Inspector (CWI) with API

tifi ti d t if b dcertification used to verify above and watch over throughout construction.