Operating practices

Activities discussed in this section will be defined for this paper as changes which are dependent on human participation to effect a reduction in waste generation. 

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There are many other sources of waste associated with process operations which can only be taken care of in the later stages of design or after the plant has been built and has become operational. For example, poor operating practice can mean that the process operates under conditions for which it was not designed, leading to waste. Such problems might be solved by an increased level of automation or better management of the process. These considerations are outside the scope of this text. 

The heights of a transfer unit ia each phase thus contribute to the overall heights of a transfer unit. Data on values of HTU for various types of countercurrent equipment have been reviewed (1,10). In normal operating practice, the extraction factor is chosen to be not greatiy different from unity, within the range of 0.5—2. 

Development of molybdenum electrodes in the 1950s permitted the use of electrically assisted melting in regenerative furnaces (81). In the 1990s, approximately one-half of all regenerative tanks ate electrically boosted. Operating practice has shown that effective use of electricity near the back end of the furnace, where the batch is added, can reduce fossil fuel needs. This lowers surface temperature and reduces batch volatilisation. 

Spent fuel can be stored or disposed of intact, in a once-through mode of operation, practiced by the U.S. commercial nuclear power industry. Alternatively, spent fuel can be reprocessed, ie, treated to separate the uranium, plutonium, and fission products, for re-use of the fuels (see Nuclear REACTORS, CHEMICAL reprocessing). In the United States reprocessing is carried out only for fuel from naval reactors. In the nuclear programs of some other countries, especially France and Japan, reprocessing is routine. 

Pilot plants are often more hazardous than process plants, even though they are smaller ia size, for many reasons. These iaclude a tendency to relax standard safety review procedures based on the small scale, exceptionally qualified personnel iavolved, and the experimental nature of the research operations the lack of estabhshed operational practice and experience lack of information regarding new materials or processes and lack of effective automatic iatedocks due to the frequendy changing nature of pilot-plant operations, the desire for wide latitude in operating conditions, and the lack of hill-time maintenance personnel. 

Among the properties sought in the solvent are low cost, avadabihty, stabiUty, low volatiUty at ambient temperature, limited miscibility in aqueous systems present in the process, no solvent capacity for the salts, good solvent capacity for the acids, and sufficient difference in distribution coefficient of the two acids to permit their separation in the solvent-extraction operation. Practical solvents are C, C, and alcohols. For industrial process, alcohols are the best choice (see Amyl alcohols). Small quantities of potassium nitrate continue to be produced from natural sources, eg, the caUche deposits in Chile. 

Any chemical treatment that reduces general corrosion rates associated with oxygen corrosion will decrease tuberculation. The exact treatment that is best is system dependent. Water chemistries and operating practices may differ widely even among similar industries... 

A good discussion of centrifuge safety design features and operating practices is found in an IChemE publication (1987). 

Operating practice different from written procedures may lead to an incident. 

The candidate tollers security policy should emphasize the importance of protecting people, property and the operational practices against loss by intentional destruction or theft. During the site visit, check to see if appropriate methods are taken to control entiy and movement of people and vehicles as a security measure. One telltale sign is that you may be denied access to an area because of another company s confidential process. Though an interference, it affirms a sound security practice. Determine whether security inspections are being held during off-duty hours. 

The policy should emphasize the importance of protecting people, property and the operational practices against loss by iiiteiitioiial destruction or theft. 

Opacity reduction is the control of fine particulate matter less than 1 ixm). It can be accomplished through the application of the systems and devices discussed for control of particulate matter and by use of combustion control systems to reduce smoke and aerosol emission. In addition, operational practices such as continuous soot blowing and computerized fuel and air systems should be considered. 

Maintenance practices are being combined more and more with operational practices to ensure that plants have the highest reliability with maximum efficiency. This has led to the importance of performance condition monitoring as a major tool in the operation and maintenance of a plant. Life cycle costs, rightly so, now drive the entire purchasing cycle and thus the... 

The management program should include written facility operating procedures. These procedures should provide ample instruction for sound operation and be consistent with the safety and environmental information, Procedures should be reviewed and updated periodically to reflect current process operating practices. Procedures provide the means for education of new employees about the process and provide education to all employees on new equipment and practices. 

Pouring water over equipment is a change from normal operating practice. It should therefore be treated as a modification. For a description of nitrate cracking of mild steel, see Reference 4. 

Use the incidents to train new staff, managers, foremen, and operators so they know what will happen if they do not follow recognized procedures and good operating practice. 

The massive power failure of November 9, 1965, affected approximately thirty million customers and initiated the most intensive examination of power system planning and operating practices in the histo-... 

In actual exchanger operational practice, the U values at the hot and cold terminals of the heat exchanger are not the same and can he significandy different if evaluated only at the spot conditions. In order to obtain an overall coefficient U that represents the transfer of heat throughout the exchanger, the U should he evaluated at the caloric temperature for physical properties and individual film coefficients... 

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