Storage tank damage

Brick buildings severely damaged, 75% external wall collapse. Fired heaters badly damaged. Storage tanks leak from base. Threshold for eardrum damage to people. Domino or knock-on radius. Pipe bridges may move. 

No item of equipment is involved in more accidents than the storage tank, probably because storage tanks are fragile and easily damaged by slight overpressure or vacuum. Fortunately, the majority of accidents involving tanks do not cause injury, but they do cause damage, loss of material, and interruption of production. 

Low-pressure storage tanks are much more fragile than pressure vessels. They are therefore more easily damaged. Some failures are described in Chapter 5. 

A more serious incident occurred at a plant in which ethylene oxide and aqueous ammonia were reacted to produce ethanolamine. Some ammonia got back into the ethylene oxide storage tank, past several check valves in series and a positive pump. It got past the pump through the relief valve, which discharged into the pump suction line. The ammonia reacted with 30 m of ethylene oxide in the storage tank. There w as a violent rupture of the tank, followed by an explosion of the vapor cloud, which caused damage and destruction over a wide area [4],... 

Flame arrester pressure drops mnst he taken into consideration when selecting and specifying them, especially when they are installed on vent systems of low pressure storage tanks, snch as API-type tanks. If the total system pressure drop exceeds the design pressure of the tank, the tank will he overpressnred and may he strnctnrally damaged. Refer to Section 6.1 for additional discnssion of this topic. 

It begins with the release of a large quantity of flammable vaporizing liquid or gas from a storage tank, process or transport vessel, or pipeline. Generally speaking, several features need to be present for a vapor cloud explosion with damaging overpressure to occur. 

A vent pipe must be fitted at the highest point of every storage tank. Wherever possible, it should be visible from the filling point and terminate in the open air, in a position where any oil vapor will not be objectionable and, in the event of an overflow, there will be no damage to property, fire risk of contamination of drains. 

Where overfilling or leakage from the tank would contribute to a fire hazard, cause damage to property or contaminate drains or sewers, a bund wall should be constructed around the tank. This should be of brick or concrete with an oil-tight lining, and sealed to the concrete base under the tank supports. The capacity of the bunded area should be at least 10 per cent greater than that of the storage tanks contained within it. 

In the production of TNT from the reaction between toluene and mixed acids (nitric/sulfuric), TeNMe forms in amounts between 0.2—0.4% of the total wt of TNT. This TeNMe has been held responsible for several expins which have occurred in TNT plants, causing fatal injuries to personnel and severe damage to facilities. These expins were attributed to the presence of TeNMe in the acid fume lines and the acid storage tanks. Mixts of TeNMe and readily oxidizable materials are known to form very powerful and sensitive expl mixts. Since TeNMe is also isolated from the nitration of Nitrobenzene (NB), the TeNMe formed in the nitration of toluene may arise from the oxidation of the aromatic ring and/or methyl group. In an effort to gain more informa-. tion on the origin of TeNMe from TNT production, radioactive carbon-14 (14C) was used as a tracer to determine the extent to which each of the carbon atoms in the toluene skeleton of the various nitro-substituted isomers contributes to... 

Initial hydrolysis would therefore lead to further hydrolysis and pH drop in storage tanks, resulting in a product that is difficult to recover and may cause irreparable damage (corrosion) in tanks, pipelines, and pumps. Therefore the pH must be kept high (9-11) to avoid acid material entering bulk storage (steep titration curve). If for product formulation requirements a product of pH 6-7 is essential, the use of buffers, e.g., phosphoric acid or citric acid, is recommended. 

A relatively small pressure can result in a very large force if it is applied over a large area. Inadequately vented atmospheric storage tanks may therefore rupture if, for some reason, e.g. a high inflow, they are subjected to a relatively low internal pressure. Large side-on structures, windows, etc. are particularly prone to damage from an explosion even at a significant distance from the epicentre. 

A temperature of 30-40 C and a moderate pressure are enough to cause a violent polymerisation, which can increase the pressure in the reactor to 1000 -1200 bar. In storage, a low polymerisation can also be dangerous for a different reason. In this case, polymer precipitates in the form of flakes causing the volume to rise, which can eventually cause the storage tanks to detonate. Butadiene can only be stored if it contains a poiymerisation inhibitor, which also plays the role of an oxidation inhibitor. Tert-butylcatechol concentrated at 0.2% is perfect for this use, but rust and water can damage the inhibitor. 

Removal of a leaking storage tank can limit liability and environmental damage. The following steps may be followed38,39 ... 

A process storage tank contained 6500 gal of ethylene oxide. It was accidentally contaminated with ammonia. The tank ruptured and dispersed ethylene oxide into the air. A vapor cloud was formed and almost immediately exploded. It created an explosive force equivalent to 18 tons of TNT, as evidenced by the damage. The events happened so rapidly that personnel could not take appropriate cover. One person was killed and nine were injured property losses exceeded 16.5 million. 

Introduction Storage tanks and many other equipment items often have a relatively low resistance to the damage that can be caused... 

More than two years later a similar accident occurred in the same company, again the pump bearing overheated but on this occasion it was not the pump which exploded but a tanker refilling at a storage tank. The explosive decomposition had not been stopped by the cold transportation hose, as in 1999, which allowed it to enter the vehicle s tank and explode. The explosion caused injury to 11 people and severe damage to the immediate surroundings. 

A heat flux rate is commonly specified during consequent modeling of hydrocarbon fires. Heat flux is considered the more appropriate measure by which to examine the radiation effects from a fire. A radiant heat flux of 4.7 kw/m (1,469 Btu/ft. ) will cause pain on exposed skin, a flux density of 12.6 kw/rrfl (3,938 Btu/ft.2) or more may cause secondary fires and a flux density of 37.8 kw/m (11,813 Btu/ft. ) will cause major damage to a process plant and storage tanks. 

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