Containment of processes

Canyon structure for containment of process equipment, which would be installed and replaced remotely by overhead cranes. This arrangement is most cost effective in that it provides for maximum use of building space since there is no need for space between process equipment Failed equipment can be replaced in less than one day and is then moved to separate maintenance shops within the canyon structure for decontamination and repair. 

Medical Sources. All medical encapsulations are done in a facility which consists of a series of five interconnected stainless steel boxes which provide primary containment of process equipment and materials. Interconnections include transfer ports, drop-through tubes, and ventilation ducts. Each containment enclosure has a floor area of 1.52 m x 0.91 m the floor level is 0.76 m above the building floor. A pair of master-slave manipulators serve each containment box. A closed circuit television system and a telescope are provided for close-up viewing of incell operations and can be moved from cell to cell as needed. General arrangement of the facility is shown in Figures 13 and 14. 

Air emission problems of breweries are relatively minor since mass emission rates are low and discharges are largely nontoxic. Emission control measures focus on containment of process odors. Water scrubbers are used on brew-house stacks to eliminate this potential problem area [7]. If spent yeasts and grains are dried on site, the resulting odors are controlled by afterburner pyrolysis before the dryer vent stacks [18]. 

Influence of the type of process fluid coking", compared to delayed coking" makes a harder coke that contains less volatile matter and forms finer grains. 

Brine Preparation. Sodium chloride solutions are occasionally available naturally but they are more often obtained by solution mining of salt deposits. Raw, near-saturated brines containing low concentrations of impurities such as magnesium and calcium salts, are purified to prevent scaling of processing equipment and contamination of the product. Some brines also contain significant amounts of sulfates (see Chemicals FROMBRINe). Brine is usually purified by a lime—soda treatment where the magnesium is precipitated with milk of lime (Ca(OH)2) and the calcium precipitated with soda ash. After separation from the precipitated impurities, the brine is sent to the ammonia absorbers. 

The discovery of new broad spectmm antibiotics has been accompanied by the development of processes for fluorinated feedstocks ring-fluorinated aromatics for those quinolones containing a fluorobenzopyridone group, and fluorinated pyridine precursors for those antibiotics containing a naphthyridine nucleus (enoxacin, tosufloxacin) (see Table 14). 

Another unique phenomenon exhibited by Hquid helium II is the Rollin film (62). AH surfaces below the lambda point temperature that are coimected to a helium II bath are covered with a very thin (several hundredths llm) mobile film of helium II. For example, if a container is dipped into a helium II bath, fiUed, and then raised above the bath, a film of Hquid helium flows up the inner waH of the container, over the Hp, down the outer waH, and drips from the bottom of the suspended container back into the helium II bath. SinHlady, if the empty container is partiaHy submerged in the helium II bath with its Hp above the surface, the helium film flows up the outer waH of the container, over its Hp, and into the container. This process continues until the level of Hquid in the partiaHy submerged container reaches that of the helium II bath. 

In contrast to the cold isostatic pressing process, the hot process can readily employ powders having spherical or noninterlocking particles. The powder is simply poured in and vibration packed into a container of desired shape. The powder mass is then simultaneously compacted and bonded during the treatment. 

AH these appHcations underscore polymer safety. If articles made of HDPE contain fiUers, processing aids, and colorants, their toxic effects must be estimated separately. 

LLDPE by itself does not present any health-related hazard on account of its chemical inertness and low toxicity. Consequently, film, containers, and container Hds made from LLDPE are used on a large scale in food and dmg packaging. Some LLDPE grades produced with unsupported metallocene catalysts have an especially high purity due to high catalyst productivity and a low contamination level of resins with catalyst residue. FDA approved the use of film manufactured from these resins for food contact and for various medical appHcations (80). However, if LLDPE articles contain fillers, processing aids, or colorants, thek health factors must then be judged separately. 

Detergents. The detergent industry consumes a large quantity of a-olefins through a variety of processes. Higher olefins used to produce detergent actives typically contain 10—16 carbon atoms because they have the desired hydrophobic and hydrophilic properties. 

Modifications of Processes Based on Air Oxidation ofp-Xylene. Since the mid-1970s, starting in Japan, several companies have developed oxidation processes to yield relatively pure forms of terephthaUc acid without a separate purification. These products, normally called medium purity terephthahc acids, contain 200—300 ppm 4-formylbenzoic acid and trace amounts of acetic acid and thus do not meet normal specifications for the highest purity grades available (80,81). 

Each plant or laboratory should adopt definite rules and procedures for electrical iastahations and work. All iastahations should be ia accordance with the National Electrical Code (NEC) for the type of ha2ard, eg. Class I flammable gas or vapor Class II organic, metallic, or conductive dusts and Class III combustible fibers and the degree of process containment, eg. Division 1 open and Division 2 closed (67). Regardless of the flammabiUty of the materials ia the iastaHed operations, changes ia procedure involving use of such materials often occur, sometimes without concurrent alteration of the electrical iastaHation. 

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