Embedded Files
Topics
Storage Tanks
Boil Over: Hot oil entry in water containing tankers/ vessels/ tanks has resulted in serious injuries and fatalities. Water turns into steam, 1600 times volume. Overpressure, rupture and violent foaming/ spraying of hot oil. Check for cleaning water, water accumulation in tanks. BP
Boil over: #6 fuel oil. 55m diameter tank. During manual gauging, an explosion occurred, due to non-intrinsically safe lamps or static spark. Tank roof landed some distance away and severed a few product lines, igniting a bund fire. Tank was under a full surface fire. As the site was remote + tank was on a hilly terrain, firefighting was limited. The access road below the bund was on fire. The tank boiled over, with a 150 m diameter fire ball. The boil over pushed product over the top of the tank, creating a wave of burning liquid that went over the 6m high bund wall and travelled more than 400m downhill. This wave entered another bund and ignited a fuel oil tank. 160 killed and more than 500 injured. Destroyed a 500 MW and 1,200 MW power plants. Poor location of large inventory tank on a hill above the facility. BP
H2S: 2 operators investigating a level malfunction in a storage tank were killed
H2S: While sampling/ dipping a cargo tank, 3 persons were exposed to H2S released from a sour crude. Stabilized crudes may have different levels of H2S. Tank inert gas blanket (=lack of O2) may enhance H2S effect, especially if they had put their heads over the opening. BP
Tank Lifted Off: Pneumatic testing of tank piping with a leaking inlet valve. Positive isolation, a must
Tank Lifted off: Upon a fire caused by a truck hitting a nearby loading gantry, a 6m diameter x 30m high tank exploded and lifted off 90m. Difficult to provide weak roof-to-shell seams for small tanks. BP
Soil: Insulated tank bottom corroded. Spilled contents. Limit insulation to 200 mm above base. WWW
Soil: Electrical heater below liquified C3= tank failed. Ground froze. Uneven settlement. Leak. WWW
FRP Tanks: In Sulfuric Acid service failed under stress corrosion cracking. In Caustic Soda service failed when its PP lining leaked. WWW
Steaming Out: After steaming out, tank was quenched with water to shorten cooling time. Vent was unable to cope and tank collapsed
Welding: Floating roof tank. Dropped welding rod melted a hole on pontoon top plate. Solvent vapors from the previous day painting work ignited and explosion. Damaged roof plates. BP
Welding: Accidents continue to happen while welding “empty” tanks, with leaking valves (poor isolation) or not fully emptying light hydrocarbons or ignoring inter-connected tanks or ignoring high LEL readings. Flammable gas reached a tank under welding via a common overflow line without valves. Failure to follow Hot Work Permit procedures and/or purge (gas-free) before welding. Gas testing at the manhole alone NOT good enough. Test at top, middle, and bottom - at all levels and in all areas
Welding: Air educator on a manhole was unable to sweep thru welding area. 3m O2 monitoring wand held by an external watcher was far away to cover the welding area. BP
Welding: Workers cut away rusted parts and welded new steel plates. Leak from acetylene cylinders used for cutting and welding, ignited. Multiple fatalities from heat, smoke or asphyxiation. BP
Welding: Wind blew welding/grinding sparks to install a safety gate on a catwalk on tank top onto an adjacent tank pressure compensating valve. BP
Welding: Naphtha tank vapor freed by filling with water and emptied. No flammable gas test done before welding. Residual naphtha in nooks and crannies vaporized. Explosion.
Similar, tank bottom residues initially covered by water caught fire.
Small amount of acid left in an acid tank produced H2 that exploded when welding started.
Sulfuric Acid tank checked OK for explosive gas. H2 as a result of corrosion had accumulated on top. Exploded when a grinder was used to cut rusted bolts
Acid leak via a corroded steam coil produced H2 and explosion when 'steam’ line was welded.
Acid under gas pressure sprayed out when pipe joints were broken. WWW
Welding: Impossible to completely vapor free pipes, vessels and tanks that contained heavy oils or polymers. Tanks assumed clean have erupted in fire or exploded when welding torch heat vaporized oil ‘hidden’ in crevices or weld laps. WWW
Diesel engine pump placed inside a water tank to empty it. CO and CO2. 2 workers asphyxiated. BP
Cleaning: MTBE Tank was cleaned. Purge N2 was sucked out. Vacuum and air entry. Explosion. BP
Cleaning: Crude tank. Vented vapors ignited by a redundant 300v DC line of an ultrasonic level sensor no longer in service. Tank lifted off and roof opened. BP
Cleaning: Nitric acid and hydrochloric acid used for cleaning. Inadvertent mix-up in a tanker. Tanker exploded with toxic orange cloud of Chlorine and Nitrogen Dioxide
Hot Work: Water tank exploded and blasted off 115m. Tank had turpentine. Caution: Even small quantities of organic liquids float on water and can form explosive mixture
Hot Work: Tank with spent H2SO4 + HC. HC via corroded shell + roof holes ignited
Explosion: Operator forgot to close steam heater valve in a mixing tank (heptane + propyl alcohol). No TAH/ TAHH. Vapor built up in the building and exploded
Bacterial Action: Anaerobic bacterial decomposition of organic matter in empty tanks can produce flammable gas that accumulate and explode
Bacterial Action: River water was used as a water layer in a Kerosene. Bacterial decomposition produced Methane that exploded. WWW
Leaking Valve: Flush water leaked thru a valve. Catastrophic reaction with chemical in tank. MIC release and fatality. (1) System to cool liquid MIC was off (2) Connecting pipe to flare was removed for maintenance and (3) Scrubber to detoxify the MIC gas was off. BP
Caution while walking on tank roof. Corroded roof plates may yield. Icing can cause slip and fall, especially on cone roof. Have caused fatal fall/ drowning
LT Failure: LAHH failure have led to overflow and fire. For volatile and flammable liquids, bunds around tanks are of no value, as the vapor quickly overflows the bund wall. LTs of control and trip should track each other and give discrepancy alarm, to detect latent failures. DCS also can estimate time to fill a tank based on initial level and pumping rate. 4 similar accidents
LT Failure: Failed float and tape measurement led operators manually calculate likely fill time for a gasoline tank fed from a ship. No LAH/ LAHH. Resulting overflow led to VCE
LT Failure: While transferring oil from one tank to another, a third tank overflowed, whose inlet valve was left open after a previous transfer. Its LT had failed and LAH was from the same LT. BP
LT Failure: Frozen water in LT. Overfilling. BLEVE in 3 storage columns in a liquid CO2 plant
Static Electricity: Oil & Gas Storage and Transportation Electrostatic Accidents https://iopscience.iop.org/article/10.1088/1742-6596/418/1/012037/pdf
Static Electricity: High inlet piping velocity with sensitive stock like naphtha results in static electricity build up spark and fire. Static electricity is also triggered by splashing in tanks. Dry air is slow to dissipate electricity. . Air in empty tanks forms explosive mixture. Light ends with low electrical conductivity + flash point <20°C, are hazardous. Uncommon in volatile gasoline as it produces a rich mixture. Less volatile naphtha, C6, C7 and BTX produce flammable mixture. Normal earthing may not be enough
Static Electricity: Explosion, while loading a barge tanker with Kerosene. Steel pipes used as dead weight at the filling hose have sparked
Static Electricity: Condensate stored in crude tank. Leak and vapor cloud. Fire hose deployed for ‘water sweep’ triggered static electricity and ignition
Static Electricity: Naphtha filling. Filling hose got switched from one tanker to another. Air was routed and accumulated on tank top. A metallic float measuring the level, while oscillating broke the earthing. Spark and explosion. Tank farm destroyed. Avoid loose metal floats
Page updated
Google Sites
Report abuse