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Attenuation of hazardous materials

So far, the emphasis has been on substituting hazardous materials or using less intensification. Now consider use of hazardous material under less hazardous conditions of less extreme temperatures or pressures, as a vapor rather than superheated liquid, or diluted, in other words, attenuation1. [Pg.630]

Operation at extremes of pressure and temperature brings a number of safety problems  [Pg.630]

With high-pressure operation, the problem of leaks becomes much more serious, since this increases the mass flowrate of fluid that can leak out through a given hole. This is particularly so when the fluid is a flashing liquid. [Pg.630]

Low pressure. Low pressures are not in general as hazardous as the other extreme operating conditions. [Pg.630]

However, one particular hazard that does exist in low-pressure plant handling flammable materials is the ingress of air with consequent formation of a flammable mixture. [Pg.630]

Low temperature. Low-temperature process (below 0°C) can contain large amounts of fluids kept in the liquid state by pressure and/or low temperature. If for any reason it is not possible to keep them under pressure or keep them cold, then the liquids will begin to vaporize. If this happens, impurities in the fluids are liable to [Pg.267]

When synthesizing a fiowsheet, the designer should consider carefully the problems associated with operation under extreme conditions. Attenuation will result in a safer plant, providing the attenuation does not increase the inventory of hazardous materials. If the inventory does not increase, then attenuation not only will make the process safer but also will make it cheaper, since cheaper materials of construction and thinner vessel walls can be used and it is not necessary to add on so much protective equipment. [Pg.268]


When synthesizing a flowsheet, the designer should consider carefully the problems associated with operation under extreme conditions. Attenuation will result in a safer plant, providing the attenuation does not increase the inventory of hazardous materials. [Pg.272]

Moderate Use less hazardous conditions, a less hazardous form of a material, or facilities which minimize the impact of a release of hazardous material or energy (also called Attenuation and Limitation of Effects). [Pg.22]

Many of the incidents in this book were the result of leaks of hazardous materials, and the recommendations describe ways of preventing leaks by providing better equipment or procedures. As we have seen, equipment can fail or can be neglected, and procedures can lapse. The most effective methods, therefore, of preventing leaks of hazardous materials are to use so little that it hardly matters if it all leaks out (intensification or minimization) or to use a safer material instead (substitution). If we cannot do this and have to store or handle large amounts of hazardous material, we should store or handle it in the least hazardous form (attenuation or moderation). Plants in which this is done are said to be inherently safer because they are not dependent on added-on equipment or procedures that might fail the hazard is avoided rather than controlled, and the safety is inherent in the design. [Pg.367]

Nobre RCM and Nobre MMM. 2004. Natural attenuation of chlorinated oiganics in a shallow sand aquifer. Journal of Hazardous Materials 110 129-137. [Pg.914]

Attenuation Another alternative to intensification is attenuation, using a hazardous material under the least hazardous conditions. Thus large quantities of liquefied chlorine, ammonia, and petroleum gas can be stored as refrigerated liquids at atmospheric pressure instead of storing them under pressure at ambient temperature. (Leaks from the refrigeration eqmpment should also be considered, so there is probably no net gain in refrigerating quantities less than a few hundred tons.) Dyestuffs which form explosive dusts can be handled as slurries. [Pg.2267]

Attenuation of risk by using hazardous materials in the least dangerous form. [Pg.396]

Moderate (attenuation and limitation of effects) Use vacuum to reduce boiling point Reduce process temperatures and pressures Refrigerate storage vessels Dissolve hazardous material in safe solvent Operate at conditions where reactor runaway is not possible Place control rooms away from operations Separate pump rooms from other rooms Acoustically insulate noisy lines and equipment Barricade control rooms and tanks... [Pg.22]

If intensification and substitution are not possible or practicable, an alternative is attenuation. This means carrying out a hazardous reaction under less hazardous conditions, or storing or transporting a hazardous material in a less hazardous form. Attenuation is sometimes the reverse of intensification, because less extreme reaction conditions may lead to a longer residence time. [Pg.35]

The third principle is the principle of attenuation, which consists of using a hazardous material in a safer form. As an example, the use of diphosgene instead... [Pg.244]

Soil and groundwater contaminated with hazardous materials create special challenges for chemists and chemical engineers. Determination of the composition and mobility of the contaminants, and the risks they pose to humans and the environment, often requires specialized analytical techniques. In some cases the hazardous nature of the contaminants may be reduced by natural attenuation due to chemical or biological activity in the soil, and a better understanding of the mechanism of attenuation can help to predict or accelerate the rate of hazard reduction. When remediation of the site is deemed necessary, cleanup or containment procedures must be tailored to the specific characteristics of the site. [Pg.58]

Attenuation Using less hazardous conditions or a less hazardous form of a material... [Pg.66]

Feedback Intrinsic, or introduced from outside, functional characteristics of a system, consisting in the fact that the variable at the exit from the system influences the input one, enhancing its value (positive feedback) or attenuating it (negative feedback). Inherent safety Inherent safety means the elimination of hazard by choice of material or design... [Pg.423]

Moderate means using materials under less hazardous conditions, also called attenuation. Moderation of conditions can be accomplished by strategies which are either physical (lower temperatures, dilution) or chemical (development of a reaction chemistry which operates at less severe conditions). [Pg.40]

For compacted, low-permeability soil liners, the U.S. EPA draft guidance recommends natural soil materials, such as clays and silts. However, soils amended or blended with different additives (e.g., lime, cement, bentonite clays, and borrow clays) may also meet the current selection criteria of low hydraulic conductivity, or permeability, and sufficient thickness to prevent hazardous constituent migration out of the landfill unit. Therefore, U.S. EPA does not exclude compacted soil liners that contain these amendments. Additional factors affecting the design and construction of CCLs include plasticity index (PI), Atterburg limits, grain sizes, clay mineralogy, and attenuation properties. [Pg.1095]


See other pages where Attenuation of hazardous materials is mentioned: [Pg.267]    [Pg.630]    [Pg.267]    [Pg.630]    [Pg.29]    [Pg.478]    [Pg.223]    [Pg.478]    [Pg.292]    [Pg.359]    [Pg.363]    [Pg.367]    [Pg.96]    [Pg.123]    [Pg.124]    [Pg.105]    [Pg.534]    [Pg.810]    [Pg.131]    [Pg.123]    [Pg.510]    [Pg.123]   
See also in sourсe #XX -- [ Pg.267 ]




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