Explosion hazards caused

A major disadvantage of an undivided cell is the fire and explosion hazard caused by electrical sparking in the case of mixing finely dispersed H2 and 02 formed during the electrolysis of water. Weintraub et al. [159] utilized porous Fe anodes that are oxidized while air or oxygen is bubbled through the solution to separate oil-water emulsions. The overall process can be explained by the following sequence of reactions [160,161] ... 

Waste disposal Assure that the plan for each laboratory operation includes plans and training for waste disposal (230). Deposit chemical waste in appropriately labeled receptacles and follow all other waste disposal procedures of the Chemical Hygiene Plan (22, 24). Do not discharge to the sewer concentrated acids or bases (231) highly toxic, malodorous, or lachrymatory substances (231) or any substances which might interfere with the biological activity of waste water treatment plants, create fire or explosion hazards, cause structural damage or obstruct flow (242). 

Fluorination of alkanesulfonyl fluorides or chlorides gives higher yields of perfluoroalkanesulfonic acids than fluorination of alkanesulfonic acids [49,51,52,54]. Another disadvantage associated with the fluorination of free alkanesulfonic acids is the potential explosion hazard caused by excessive amounts of oxygen difluoride and hypofluorites formed as by-products [55]. 

Heating triacetylboron at temperatures above its melting poiat, 123°C, causes a rearrangement to B20(0CCH2)4 (15). An explosive hazard is also generated by dissolving BF ia anhydride (see Boron compounds). 

Vapor Density (VD) — the mass per unit volume of a given vapor/gas relative to that of air. Thus, acetaldehyde with a vapor density of 1.5 is heavier than air and will accumulate in low spots, while acetylene with a vapor density of 0.9 is lighter than air and will rise and disperse. Heavy vapors present a particular hazard because of the way they accumulate if toxic they may poison workers if nontoxic they may displace air and cause suffocation by oxygen deficiency if flammable, once presented with an ignition source, they represent a fire or explosion hazard. Gases heavier than air include carbon dioxide, chlorine, hydrogen sulfide, and sulfur dioxide. 

Safety air technology, including risk assessment, that minimizes damages and hazards caused by accidents, fire, and explosion... 

This study investigated risks to the public from serious accidents which could occur at the industrial facilities in this part of Essex, U.K. Results are expressed as risk to an individual and societal risk from both existing and proposed installations. Risk indices were also determined for modified versions of the facilities to quantify the risk reduction from recommendations in the report. Nine industrial plants were analyzed along with hazardous material transport by water, road, rail and pipeline. The potential toxic, fire and explosion hazards were assessed for flammable liquids, ammonia, LPG, LNG, and hydrogen fluoride (HE). The 24 appendices to the report cover various aspects of the risk analysis. These include causes and effects of unconfined... 

It is important that the fire and explosion hazards of an area be carefully examined, because the expense of consistent installation of all the motors, controls, switches, instruments, and wiring can be considerable. Tables 14-8A and 14-8B summarize the National Eire Code for hazardous locations. It is equally important to be consistent and not install explosion-proof motors with nonexplosion proof wiring, because a failure in the conduit can still cause considerable damage. 

On release, vapours heavier than air tend to spread (i.e. to slump ) at low level and will accumulate in pits, sumps, depressions in ground etc. This may promote a fire/ explosion hazard, or a toxic hazard, or cause an oxygen-deficient atmosphere to form, depending on the chemical. 

Finely divided aluminium powder or dust forms highly explosive dispersions in air [1], and all aspects of prevention of aluminium dust explosions are covered in 2 recent US National Fire Codes [2], The effects on ignition properties of impurities introduced by recycled metal used to prepare dust were studied [3], Pyrophoricity is eliminated by surface coating aluminium powder with polystyrene [4], Explosion hazards involved in arc and flame spraying of the powder are analysed and discussed [5], and the effect of surface oxide layers on flammability was studied [6], The causes of a severe explosion in 1983 in a plant producing fine aluminium powder are analysed, and improvements in safety practices discussed... 

A mixture of the alcohol with formic acid rapidly self-heated, then reacted violently [1], A stirred mixture with cyanoacetic acid exploded violently after application of heat [2], Contact with acids causes self-condensation of the alcohol, which may be explosively violent under unsuitable physical conditions. The general mechanism has been discussed [3], The explosion hazards associated with the use of acidic catalysts to polymerise furfuryl alcohol may be avoided by using as catalyst the condensation product of 1,3-phenylenediamine and l-chloro-2,3-epoxypropane [4], See Nitric acid Alcohols (reference 6)... 

The earlier references, which state that this powerful oxidant is stable when pure, but explosive when formed as a layer on metallic potassium [1,2], are not wholly correct [3], because the superoxide is manufactured uneventfully by spraying the molten metal into air to effect oxidation [4], Previous incidents appear to have involved the explosive oxidation of unsuspected traces of mineral oil or solvents [3]. However, mixtures of the superoxide with liquid or solid potassium-sodimn alloys will ignite spontaneously after an induction period of 18 min, but combustion while violent is not explosive [3], The additional presence of water (which reduces the induction period) or hydrocarbon contaminant did produce explosion hazards under various circumstances [5], Contact of liquid potassium with the superoxide gives no obvious reaction below 117°C and a controlled reaction between 117 and 177°C, but an explosive reaction occurs above 177°C. Heating at 100°C/min from IT caused explosion at 208°C [6],... 

An experimental investigation of explosion hazards in lithium-sulfinyl chloride cells on forced discharge showed cathode limited cells are safe, but anode limited cells may explode without warning signs [1]. Extended reversal at -40°C caused explosion on warming to ambient temperature, owing to thermal runaway caused by accelerated corrosion of lithium [2], The violent explosion of a large prismatic cell of a battery is described [3], Another study of explosion mechanisms in lithium/thionyl chloride batteries is reported [4]... 

Reaction to give tetrafluorooxathietane 2,2-dioxide (tetrafluoroethane sultone) had been used industrially and uneventfully, but reaction with excess sulfur trioxide may cause explosive decomposition to carbonyl fluoride and sulfur dioxide [1]. An incident involving the same explosion hazard was reported 11 years later [2], Use of inert gas to prevent explosion has been patented [3],... 

Attrition of particulate materials occurs wherever solids are handled and processed. In contrast to the term comminution, which describes the intentional particle degradation, the term attrition condenses all phenomena of unwanted particle degradation which may lead to a lot of different problems. The present chapter focuses on two particular process types where attrition is of special relevance, namely fluidized beds and pneumatic conveying lines. The problems caused by attrition can be divided into two broad categories. On the one hand, there is the generation of fines. In the case of fluidized bed catalytic reactors, this will lead to a loss of valuable catalyst material. Moreover, attrition may cause dust problems like explosion hazards or additional burden on the filtration systems. On the other hand, attrition causes changes in physical properties of the material such as particle size distribution or surface area. This can result in a reduction of product quality or in difficulties with operation of the plant. 

Chemical plants contain a large variety of hazards. First, there are the usual mechanical hazards that cause worker injuries from tripping, falling, or moving equipment. Second, there are chemical hazards. These include fire and explosion hazards, reactivity hazards, and toxic hazards. 

Dust presents a different type of hazard, because while it has a lower explosive limit, it does not have an upper explosive limit. This can result in a primary explosion, followed by secondary explosions as new air is provided. Secondly, dust does not diffuse away from its point of release, but settles out of the air and accumulates into layers. Unlike vapor, the dust explosion is caused by the radiant heat from one particle igniting the next. Because of this, the lower explosive limits for dusts are greatly higher than for vapors. Also, the size and shape of the dust particles are important factors in effecting its lower explosive limit. 

Petroleum and chemical related hazards can arise from the presence of combustible or toxic liquids, gases, mist, or dust in the work environment. Common physical hazards include ambient heat, bums, noise, vibration, sudden pressure changes, radiation, and electric shock. Various external sources, such as chemical, biological, or physical hazards, can cause work related injuries or fatalities. Although all of these hazards are of concern this book primarily concentrates on fire and explosions hazards that can cause catastrophic events. 

D1 - May cause violent polymerization, possibly with heat/toxic or flammable gas generation or with explosive reaction causes pressurization D2 - Can become highly flammable in use causes pressurization D3 - Contact with substance liberates toxic gas causes pressurization D4 - Innocuous and nonflammable gas generation causes pressurization D5 - Contact with adds produces combustion enhancer (e.g., OJ E - Generates water soluble toxic products F - May be hazardous but unknown G - Reaction may be intense or violent H - Possible exposure to radiation... 

In addition to causing injuries and fatalities to plant personnel and the public, reactive incidents can also result in environmental harm and equipment damage. These impacts may be due to fires, explosions, hazardous liquid spills, toxic gas releases, or any combination of such (Figure 6). Fires and explosions are the most frequent occurrence in CSB data, followed by toxic gas releases. 

Because of the hazards caused by such explosive boiling incidents, industry has supported research programs seeking answers to several basic questions ... 

A brief example helps If I have ajar containing gasoline it is a potential explosion hazard, or is it If the jar is sealed vapor tight, where s the hazard Now take the eap off the jar Is there a hazard If so, to whom The air blowing aeross the jar and the vapor pressure of the liquid will cause it to evaporate. Again, no problem — maybe or maybe not. However, if we are in a confined space with an source of ignition, there may be an explosion. Similarly, if the container falls off the shelf and releases the gas, there is an additional hazard which may lead to fire or explosion. 

Heating ammonium nitrate can present a severe explosion hazard. When heated above 210°C, its decomposition is exothermic, producing nitrous oxide and water vapor. In closed confinement, heating the molten mass can cause a pressure build-up. Above 300°C, there is rapid evolution of nitrogen, water... 

Skin contact of the powder can cause severe irritation. Mixing the powder form of the compound with water can produce explosive reactions with liberation of large quantities of heat. The reaction occurs after a few minutes delay (Mellor, J. W. 1941. Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. 3, pp. 673. London Longmans Green). The presence of moisture in storage containers or bottles may produce an explosion hazard. Hydration of granular lumps, however, is slow and smooth. 

Most reactions are violent. Accidental contact with a number of organics and inorganic substances may present a fire or explosion hazard. Rapid mixing with water can be explosive. The compound is highly corrosive. Skin contact can cause a severe burn. Vapors are highly irritating to eyes, nose and mucous membranes. (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd. New York John Wiley Sons.)... 

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