Vapor spread

Many flammable liquids are used for a variety of purposes in bench work, either in semi-closed containers or in open trays. If spillage occurs due to breakage of apparatus or plant, or carelessness in handling, the liquid is distributed over a large area and considerable vapor is produced. Fires due to the ignition of vapors spread with extreme rapidity over the exposed surface of the liquid and the amount of flame and heat given off quickly increases. 

Erosion failure of a pipeline released liquids near autoignition temperature. Vapors spread and ignited causing severe damage to the facility 76,000,000 loss... 

AM. Kettle No. 3 discharge piping cracks. Contents of kettle start dumping to the curb. Isopentane vapors spread as material flashes. (Concluded from data). 

Although vapor spreads redially through the packing quite rapidly... 

In the atmosphere-ocean system, the subtropical oceanic areas are the main supply regions for atmospheric water vapor. As this vapor spreads north and over the continents and decreases as a result of precipitation, the S values decrease until they reach values of — 6/mil in fresh water in midlatitudes and about -30/mil in polar precipitations. Since the S values refiect the fraction of moisture removed and since this fraction is controlled by the atmospheric temperature, the S values of precipitation are strongly correlated with the atmospheric temperature (Epstein et al., 1977). ratios serve as oceanic water... 

When vaporization occurs in an open container, as when water evaporates from a bowl, the Vapor spreads away from the liquid. Little, if any, is recaptured at the surface of the liquid. Equilibrium never occurs, and the vapor continues to form until the liquid evaporates to dryness. Substances with high vapor pressure (such as gasoline) evaporate more quickly than substances with low vapor pressure (such as motor oh). Liquids that evaporate readily are said to be volatile. 

Direct water spray to plume to reduce vapor spread. Contain resultant corrosive solution. 

An interesting consequence of covering a surface with a film is that the rate of evaporation of the substrate is reduced. Most of these studies have been carried out with films spread on aqueous substrates in such cases the activity of the water is practically unaffected because of the low solubility of the film material, and it is only the rate of evaporation and not the equilibrium vapor pressure that is affected. Barnes [273] has reviewed the general subject. 

Many complex systems have been spread on liquid interfaces for a variety of reasons. We begin this chapter with a discussion of the behavior of synthetic polymers at the liquid-air interface. Most of these systems are linear macromolecules however, rigid-rod polymers and more complex structures are of interest for potential optoelectronic applications. Biological macromolecules are spread at the liquid-vapor interface to fabricate sensors and other biomedical devices. In addition, the study of proteins at the air-water interface yields important information on enzymatic recognition, and membrane protein behavior. We touch on other biological systems, namely, phospholipids and cholesterol monolayers. These systems are so widely and routinely studied these days that they were also mentioned in some detail in Chapter IV. The closely related matter of bilayers and vesicles is also briefly addressed. 

Acrylonitrile is combustible and ignites readily, producing toxic combustion products such as hydrogen cyanide, nitrogen oxides, and carbon monoxide. It forms explosive mixtures with air and must be handled in weU-ventilated areas and kept away from any source of ignition, since the vapor can spread to distant ignition sources and flash back. 

Solutions of these fire retardant formulations are impregnated into wood under fliU cell pressure treatment to obtain dry chemical retentions of 65 to 95 kg/m this type of treatment greatly reduces flame-spread and afterglow. These effects are the result of changed thermal decomposition reactions that favor production of carbon dioxide and water (vapor) as opposed to more flammable components (55). Char oxidation (glowing or smoldering) is also inhibited. 

Chemical Phase Inversion Svmrnetrical phase-inversion membranes (Fig, 22-71) remain the most important commercial MF membranes produced. The process produces tortiioiis-Bow membranes. It involves preparing a concentrated solution of a polvrner in a solvent. The solution is spread into a thin film, then precipitated through the slow addition of a nonsolvent, iisiiallv w ater, sometimes from the vapor phase. The technique is irnpressivelv v ersatile, capable of producing fairlv uniform membranes wFose pore size rnav be varied within broad limits. 

Determination of the equilibrium spreading pressure generally requires measurement and integration of the adsorption isotherm for the adhesive vapors on the adherend from zero coverage to saturation, in accord with the Gibbs adsorption equation [20] ... 

---