Releases gases/vapors

The key point here is to determine if flammable or combustible materials are being processed under conditions of temperature and pressure such that, if a release occurs, a significant quantity of the material may be released into the air as either a gas, vapor, mist, or aerosol. If such conditions are present, the user should assume that the potential for a vapor cloud explosion exists. Otherwise, VCE hazards can be ignored. 

An 800-lb tank of chlorine is stored at a water treatment plant. A study of the release scenarios indicates that the entire tank contents could be released as vapor in a period of 10 min. For chlorine gas, evacuation of the population must occur for areas where the vapor concentration exceeds the ERPG-1. Without any additional information, estimate the distance downwind that must be evacuated. 

Accidentally where the possibility exists of a simultaneous release of ignitable concentrations of gas (vapor) and failure of electrical equipment. 

REDIFEM—This fire model has applications including steady state releases of compressible gas/vapor, incompressible liquid and transient release from a gas vessel, Gaussian Plume models, continuous free momentum, BLEVE, and confined and unconfined vapor cloud explosions. REDIEEM is reported to have internal validation with ISO 9001 and checked against PHAST and ERED. 

LNG tanks are designed for fairly low pressures, typically less than 1.72 MPa (250 psi), otherwise their advantage over storing natural gas as CNG would be lost. As LNG warms, vapor is produced that builds up pressure in the tank. To protect the tank from rupture due to over-pressure, vent valves are included that will release some vapor when the maximum set pressure is reached. Vent valves come in two types those that reseat when the pressure in the tank falls below the maximum, and those that don t. The second type is used only to protect the tank from over-pressure rupture, while the first type is used to control the pressure in the tank. Often they are used together in the same tank. Both types of vent valves may be made from stainless steel, brass, and aluminum materials compatibility problems are rare because of the cleanliness of LNG. 

Finite duration release of a gas/vapor from a vessel/source containing gas or a two-phase mixture and... 

Safety planners should keep in mind that the process equipment and structures upwind of the release point and vapor barrier can influence the performance of the vapor barrier. It is well recognized that these structures and equipment will affect the flow of the released gas or vapor around them and the degree of mixing that occurs. 

Pure nitrogen (N2) and carbon dioxide (C02). In the lab, carbon dioxide gas may be released by vaporizing small quantities of dry ice in an Erlenmeyer flask with stopcock, plastic tube and small pipette for the introduction of the gas... 

Boiling liquid expanding vapor explosions occur when there is a sudden release of vapor, containing liquid droplets, due to the failure of a storage vessel. A serious incident involving the failure of a Liquified Petroleum Gas (LPG) storage sphere occurred at Feyzin, France, in 1966, when the tank was heated by an external fire fueled by a leak from the tank see Lees (2004) and Marshall (1987). 

The jumping gene adaptations of GA and SA have been used extensively for solving problems of industrial importance in chemical engineering (see Chapter 2). Very recently, Ramteke and Gupta (2007) have carried out the MOO of an industrial semi-batch nylon-6 reactor using the rate, of release of vapors, and the temperature, Tj f), of the jacket fluid, as decision variables. They obtained the two optimal histories using... 

In general, the temperatures in the gas and liquid both will change with time primarily because of the release (or use) of latent heat at the interface as vapor condenses (or liquid vaporizes). However, for present purposes, we neglect this effect and consider that T = Too = constant everywhere in the system. In terms of practical application, this is a severe assumption, and it is well known that thermal effects can have an important influence on the dynamics of gas/vapor bubbles. However, the isothermal problem retains many of the interesting qualitative features of the lull problem and is sufficiently general for our present illustrative purposes. Thus we assume that... 

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