Crude oil fires

S. M. DeCorso, R. A. Symonds, and G. Vermes, Crude Oil Firing in the Utilif Gas Turbine, ASME 71-WA/GT-ll, American Society of Mechanical Engineers, New York, 1971. 

It may be mentioned that starting with ash and soot from crude oil-fired stations, the resulting metals are the same, but the main leaching residue is carbon. This residue is initially burned and the ash is leached again to increase the total yield of vanadium. In the same operation, the concentration of iron is reduced by precipitation of jarosite. During leaching, the redox potential is controlled by SO2 addition to keep vanadium in its IV-valent state. 

Another phenomenon associated with a crude oil fire is stopover. Basically, die same principles that are responsible for a boilover are the cause of a stopover. The fundamental difference is that in a stopover the reaction is from water that has entered the tank since the start of the fire. Usually this introduction is die result of firefighting activities. A slopover will occur at some point after the heat wave lias been formed. Eidier the water from the hose streams or, after the bubbles collapse, the water in the foam will sink into the oil, contacting the heat wave, where it is converted to steam, and die agitation of the liquid surface spills some amount of oil over the tank rim. 

BLEVE (Boiling Liquid Expanding Vapor Explosion) See Boilover the same phenomenon may occur in a pressurized container, resulting in an explosion or bursting of the tank or vessel in which a fire is occurring. The term is almost exclusively used to describe a disastrous effect from a crude oil fire. 

Most burns produce an abundance of particulate matter. Particulate matter at ground level is a health concern close to the fire and under the plume, although concentrations decline rapidly downwind from the fire. The greatest concern is the smaller or respirable particles that are 10 pm or less in size. Concentrations at ground level (1 m) can still be above normal health concern levels (150 pm/m ) as far downwind as 500 m from a small crude oil fire, such as from the amount of oil that could be contained in a 500-m long boom. 

Volatile oxygenated compounds are also formed when oil bums. These compounds are sometimes generally referred to as carbonyls or by their main constituents, aldehydes and ketones. Studies have shown that carbonyls from crude oil fires are at very low concentrations and are not a health concern even close to the fire. Carbonyls from diesel fires are slighdy higher but are still below health concern levels. 

Camera approach Visually observe the waterwall or refractory wall directly to be certain flames are not touching the walls, causing potentially catastrophic leaks at sites like crude oil (fired) heaters. Besides spotting flames contacting the external tube surface inside the firebox, the camera can also spot other signs of impingement like tubes with a cherry-red color or bulges in the tube walls [12]. 

The fuels consumed in the fire were treated wood, penta, and creosote (coal tars). Both are considered combustible liquids, with flash points above 160° F (CC). Vapor conditions within the headspaces of tanks can, however, reach explosive conditions, and the introduction of an ignition source resulted in spontaneous combustion. Under ideal conditions, creosote burns similar to crude oil, and in standard lab burn tests, has an average burn rate of 4 mm/min. There is no data on the burn rate of penta however, its vapors would have likely burned at much slower rates and a series of complex chemical transformations would have occurred. 

In addition to the distillation of crude oil coming into the refinery, stills of various designs are used in other types of service throughout the refinery. Cracked products are separated in distillation equipment which is very similar to an atmospheric crude pipe still. The principal difference is that these products are hot from the cracking operation, so that a fired heater is not required. 

Indirect fired heaters (sometimes called line heaters) heat the gas stream before and/or after the choke so that the gas is maintained above the hydrate temperature. Indirect fired heaters can also be used to heat crude oil for treating, heat a hot fluid circulating medium (heat medium) that is used to provide process heat, etc. 

Fire tubes, especially in heater treaters, where they can be immersed in crude oil, can become a source of ignition if the tube develops a leak, allowing crude oil to come in direct contact with the flame. Fire tubes can also be a source of ignition if the burner controls fail and the tube overheats or if the pilot is out and the burner turns on when there is a combustible mixture in the tubes. 

Fire tubes can lead to fire or explosion if there is a leak of crude oil into the tubes or failure of the burner controls. An explosion could be sudden and lead directly to injury. Therefore, a high level of safety is required. 

The oil for an oil-base mud can be diesel oil, kerosene, fuel oil, selected crude oil, or mineral oil. There are several requirements for the oil (1) API gravity = 36° - 37°. (2) flash point = 180°F or above, (3) fire point = 200°F or above, and (4) aniline point = 140°F or above. Emulsifiers are more important in oil-base mud than in water-base mud because contamination on the drilling rig is very likely, and it is very detrimental to oil mud. Thinners, on the other hand, are far more important in water-base mud than in oil-base mud oil is dielectric, so there are no interparticle electric forces to be nullified. 

The moist sulfide readily oxidises in air exothermally, and may reach incandescence. Grinding in a mortar hastens this [1]. The impure sulfide formed when steel processing equipment is used with materials containing hydrogen sulfide or volatile sulfur compounds is pyrophoric, and has caused many fires and explosions when such equipment is opened without effective purging. Various methods of purging are discussed [2], Formation of pyrophoric FeS in bitumen tanks is considered as a cause of spontaneous ignition and explosion in the head space [3], A detailed study of formation of possibly pyrophoric sulphides from rust in crude oil tankers has been made [4],... 

The monoaromatic compounds benzene, toluene, ethylbenzene and xylene, commonly found in crude oil, are often jointly called BTEX compounds. The most harmful of these compounds is benzene, which is a known carcinogen. BTEX compounds occur naturally near natural gas and petroleum deposits and are detected in the fumes of forest fires. Most of the highly volatile BTEX compounds released by human activity originate from fuel use and end up as pollutants in the air. Inhaling BTEX-polluted air is also the greatest hazard to humans by these compounds. BTEX compounds are water-soluble, and therefore, improper handling can also cause groundwater contamination. 

One accident mitigation procedure is called emergency material transfer, in which the material is transported away from the accident site before it becomes involved. We plan on mitigating a crude oil tank fire scenario by pumping the tank empty in 1 hr total time. 

A pump roller bearing failure in a crude oil refinery initiated the fracture of the motor shaft and the pump bearing bracket. The pump casing then broke, releasing hot oil, which au-toignited. Secondary pipe and flange failures contributed fuel to the fire. Plant damage totaled over 15 million. 

Philadelphia, PA, USA, Tanker, Explosion/Fire Incident occurred during unloading of crude oil. 8,10(1,000 loss... 

Two crude oil supertankers (each 330,000 dwt.) collided and fire occurred. 

Structural failure of 121,000 dwt. Crude oil tanker during incorrect ballasting led to a release of contents resulting in explosions and fires. 

Caribbean Ocean, Supertanker, Collision/Fire Two fully loaded crude oil supertankers collide 1 fatality, Loss estimated at 150 million... 

Geelong, Australia, Refinery, Fire Pump bearing failure released crude oil... 

The provisions for spacings are based on the commodity stored, pressure, temperature, and fire protection measures afforded to each tank. Each parameter adjusts the minimum requirements. For large tanks and those containing crude oil, heated oil, slop oil or emulsion breading materials additional spacing requirements should be considered. These include the following ... 

Floating exploration and production facilities are sometimes provided on jackup rigs, semi-submersible vessels or ex-crude oil shipping tankers converted to production treatment vessels. These facilities are essentially the same as fixed offshore platform or installations except they are moored in place or provided with a temporary support structure instead of provided with fixed supports to the seabed. The major process fire and explosion risks are identical to the risks produced on offshore platforms. They have one addition major facility risk, that is the maintenance of buoyancy of the installation. Should fire or explosion effects cause a loss of buoyancy (or even stability) the entire facility is at risk of submergence. Adequate compartimization and integrity assurances must be implemented in these instances. 

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