Explosions, in chemical plants

Fllxborough, UK Vapor Cloud Explosion in Chemical Plant... 

Two incidents of pump explosions in chemical plants are reported, both occasioned by nitric acid reaching parts of a pump it should not and there corroding metal or contacting electrics. Proper pump selection, installation and maintenance would have avoided these incidents. 

Introduction Fire and explosions in chemical plants and refineries are rare, but when they do occur, they are very dramatic. 

TCDD and other chlorinated dibenzo-J -di-oxins are released during the combustion of many polychlorophenols and also occur as contaminants in various chemicals such as the herbicide 2,4,5-trichlorophenoxyacetic acid. Most high-level exposure to 2,3,7,8-TCDD and other dioxins results from accidental releases or explosions in chemical plants or storage facilities for dioxin-containing chemicals. Because of the persistence of dioxin congeners in the environment and their potential for bioaccumulation, exposure may occur via the soil, air (especially when dioxins occur as combustion products), or water. When bound to components of the soil, the health hazard from 2,3,7,8-TCDD is reduced compared to ingestion of the pure compound. However, its bioavailability varies with the specific media in which it occurs. 

Lloyd, F.C., 1989, Hazards of fire and explosion in chemical plant operations. Hazards X Process Safety in Fine and Speciality Chemical Plants. Symposium Series No. 115. 207-222 (IChemE. Rugby. UK),... 

Conversely, the absence of such a plan can detract from enterprise value. Consider for a moment, the impact on a company s market value from indusUial incidents. A 2009 research study titled How Does the Stock Market Respond to Chemical Disasters by Gunther Capelle-Blancardy and Marie-Aude Lagunaz, examined 64 explosions in chemical plants and refineries worldwide between 1990 and 2005 and found that, on average, petrochemical firms experience a drop in market value of... 

In selec ting the machines of choice, the use of specific speed and diameter best describe the flow. Figure 10-67 shows the characteristics of the three types of compressors. Other considerations in chemical plant service such as problems with gases which may be corrosive or have abrasive solids in suspension must be dealt with. Gases at elevated temperatures may create a potential explosion hazard, while air at the same temperatures may be handled qmte normally minute amounts of lubricating oil or water may contaminate the process gas and so may not be permissible, and for continuous-process use, a high degree of equipment rehability is required, since frequent shutdowns for inspec tion or maintenance cannot be tolerated. 

X T. M-ost accidents in chemical plants result in spills of toxic, flammable, and explosive materials. 

The data in Figure 6-23 are valid only for TNT explosions occurring on a flat surface. For explosions occurring in the open air, well above the ground, the resulting overpressures from Figure 6-23 are multiplied by 0.5. Most explosions occurring in chemical plants are considered... 

There have been occasions in which relatively large quantities of dioxins were released as the result of chemical or industrial accidents. Explosions at chemical plants in Seveso, Italy, in 1976 and at Bhopal, India, in 1984 are examples of such incidents. High levels of dioxin have also been found in animal feed on a few occasions the source and mechanism of this contamination have not always been clear. 

Detonation (and Explosion, Danger in Chemical Plants. Vlad Sima gives in TechChem (Prague) 12(2), 66-69(1962) CA 61, 526(1964) examples of plant construction with description of inherent dangers of explosions... 

Combustions of gas-air mixtures as self-sustained chemical reactions occur only within well-defined volumetric ratios. The gas concentration - by volume - is limited by a lower value - Lower Explosive Limit (LEL) - and an upper value - Upper Explosive Limit (UEL) - in order to maintain an expanding reaction zone in the gas-air mixture. Below the LEL and above the UEL an explosive gas-air atmosphere will not be formed. Table 1.1 summarizes LEL and UEL for gases in chemical plants, the oil and gas industry and in coal mines. 

Accumulators in increased safety - e - cover traction batteries for locomotives in coal mines (see Fig. 6.4) as well as batteries for forklifts in chemical plants or other transportation vehicles running in hazardous areas powered by their own energy storage system. Much smaller accumulators are used as a mains-independent power source for handlamps and caplamps (Fig. 6.65) used in potentially explosive atmospheres. 

The inspiration for this book was a series of courses on Explosion Protection given in chemical plants and the enthusiastic response to these courses, as well as the progress made in protection techniques, for example in pressurization, in more recent times. 

The use of dangerous substances in chemical plants such as oil refineries, pesticide plants etc., can cause major accidents (toxic releases, fires, explosions etc.). Such an accident might result in adverse effects on the health of the workers at the chemical plant as well as on the population in the area around of it. 

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