Process containment systems

Describe several types of process containment systems. 

The function of process containment systems is to contain liquids or vapors and prevent them from entering the environment or creating a hazard. Examples of the different types of containment systems are ... 

Some of the more common engineering controls are fire alarms and detection systems, toxic gas alarms and detection systems, redundant alarms and shutdown devices, automatic shutdown devices, and process containment systems. 

Maximum potential quantity The maximum amount of a chemical that can be released from a process containment system. Such a system may be an isolated pressure vessel and associated piping or two or more interconnected and communicating vessels without isolation capability. This quantity is different from and often much greater than both the typical chemical inventory and design maximum inventory for a containment system. 

The fourth level of defense-in-depth is activated if all of the previous levels fail and radioactivity is released from the power-generating system. This level consists of containment systems and accident management processes that prevent the dissernination of radioactivity to the atmosphere even if it is released from the nuclear systems. The fifth level is the provision for emergency planning outside the plant boundary in the highly unlikely event that all of the first four levels of defense were to fad. 

In vacuum drying or other processes containing atmospheres of 100 percent vapor, the temperature of liquid vaporization will equal or exceed the saturation temperature of the liquid at the system pressure. (When a free liquid or wetted surface is present, drying will occur at the saturation temperature, just as free water at I0I.325 kPa vaporizes in a 100 percent steam atmosphere at I00°C.)... 

Systems with self-loading compactors. Container size and utilization are not as critical in stationaiy-coutaiuer systems using self-loading collec tion vehicles equipped with a compaction mechanism (see Fig. 25-61 and Table 25-59) as they are in hauled-container systems. Trips to the disposal site, transfer station, or processing station are made after the contents of a number of containers have been col-lec ted and compacted and the collec tion vehicle is fuU. Because a variety of container sizes and types are available, these systems may be used for the coUection of all types of wastes. Container sizes vaiy from relatively small sizes (0.6 m ) to sizes comparable to those handled with a hoist truck (see Table 25-58). 

Use of plant, processes and systems of work which minimize the generation of, or suppress and contain, spills, leaks, dust, fumes and vapours. 

Plant or processes or systems of work which minimize generation of, or suppress or contain, the hazardous dust, fume, biological agent etc. and limit the area of contamination in the event of spills and leaks. 

Technology Descriptions The use of thermoplastic solidification systems in radioactive waste disposal has led to the development of waste containment systems that can be adapted to industrial waste. In processing radioactive waste with bitumen or other thermoplastic material (such as paraffin or polyethylene), the waste is dried, heated and dispersed through a heated, plastic matrix. The mixture is then cooled to solidify the mass. 

A distributed control system (DCS) normally uses input and output modules which contain eight, sixteen, or more inputs or outputs. Failure of the module will simultaneously disable a large number of control loops. Attention to the assignment of input/output points to the modules makes the plant more tolerant of a failure of an input or output module (CCPS, 1993a). For a more detailed discussion of process control systems, see the process control part of Section 4.4, and Sections 6.4 and 6.5. 

These accidents would have been prevented by 1) adequate process safety design, 2) proper-procedures to prevent the initiation, 3) hazard evaluation procedures to identify and correct Iia/.ards hc fure accident occurrence, and 4) containment systems to prevent release into the aimosphci c,... 

Another significant advance of the Hinsberg thiophene synthesis has explored the reactivity of diketosulfides in place of the use of diethylthiodiglycolate. This process has been extensively utilized for the preparation of novel thiophene containing systems. With glyoxal as condensation partner, the utility of this method has been pioneered Miyahara et al. in the synthesis of novel thiophenophanes 19, 20, and 21. 

Solution of alkali metals in liquid ammonia, containing the so-called solvating electrons, may be used as an alternative homogeneous system to initiate polymerization by an electron transfer process. This system suffers, however, from complications resulting from proton transfer from ammonia leading to the formation of NH2- ions, which in turn initiate further polymerization.4... 

Let us now consider what happens when, during the above process, the system contains a mass M of solvent and a mass p of solute and a further small quantity dp of the latter goes into solution. 

The effects of manganese on the cobalt/bromide-catalyzed autoxidation of alkylaromatics are summarized in Figure 17. The use of the Mn/Co/Br system allows for higher reaction temperatures and lower catalyst concentrations than the bromide-free processes. The only disavantage is the corrosive nature of the bromide-containing system which necessitates the use of titanium-lined reactors. 

The different location of polar and amphiphilic molecules within water-containing reversed micelles is depicted in Figure 6. Polar solutes, by increasing the micellar core matter of spherical micelles, induce an increase in the micellar radius, while amphiphilic molecules, being preferentially solubihzed in the water/surfactant interface and consequently increasing the interfacial surface, lead to a decrease in the miceUar radius [49,136,137], These effects can easily be embodied in Eqs. (3) and (4), aUowing a quantitative evaluation of the mean micellar radius and number density of reversed miceUes in the presence of polar and amphiphilic solubilizates. Moreover it must be pointed out that, as a function of the specific distribution law of the solubihzate molecules and on a time scale shorter than that of the material exchange process, the system appears polydisperse and composed of empty and differently occupied reversed miceUes [136],... 

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