Preliminary Selections

If distillation is the choice of separator, then some preliminary selection of the major design variables must be made to allow the design to proceed. The first decision is operating pressure. As pressure is raised,... 

The important factors to consider in the preliminary selection of a diyer are the following ... 

Preliminary Selections Assembling background information permits tentative selection of promising equipment and rules out clearly unsuitable types. If the material to be processed is a shiny or pumpable suspension of sohds in a hquid, several methods of mechanical separation may be suitable, and these are classified into setfiiug and filtration... 

TABLE 25-71 Important Factors in Preliminary Selection of Landfill Sites... 

Figure 9-88 illustrates a falling film type absorber using water jacketed tubes in the cooler-absorber. The tails tower removes last traces of HCl in the vents. Figure 9-89 is a preliminary selection chart for this type of unit. 

Figure 9-89. Preliminary selection charts for HCI towers. Used by permission of Falls Industries, Inc.

In view of the widespread use of welded joints in equipment and structures exposed to corrosion, it is necessary to know whether such welded joints will demonstrate satisfactory resistance to attack. It is not necessary to include welded specimens of all materials in a preliminary study to discover which of them have satisfactory resistance to a particular environment. Weld tests can be postponed until the preliminary selection has been made, or, alternatively, those materials expected in advance to be most likely to be resistant can be exposed in the welded condition so as to expedite the final answer. 

A variety of equipment has been developed for gas cleaning. The principal types used in the process industries are listed in Table 10.11, which is adapted from a selection guide given by Sargent (1971). Table 10.11 shows the general field of application of each type in terms of the particle size separated, the expected separation efficiency, and the throughput. It can be used to make a preliminary selection of the type of equipment likely to be suitable for a particular application. Descriptions of the equipment shown in Table 10.11 can be found in various handbooks Perry et al. (1997), Schweitzer (1997) and in specialist texts Strauss (1975). Gas cleaning is also covered in Volume 2, Chapter 1. 

The selection guides given by Lowrison (1974) and Marshall (1974), which are reproduced in Tables 10.12 (see p. 465) and 10.13, can be used to make a preliminary selection based on particle size and material hardness. Descriptions of most of the equipment listed in these tables are given in Volume 2, Chapter 2 or can be found in the literature Perry et al. (1997), Hioms (1970), Lowrison (1974). The most commonly used equipment for coarse size reduction are jaw crushers and rotary crushers and for grinding, ball mills or their variants pebble, roll and tube mills. 

The selection chart given in Figure 10.57, which has been adapted from a similar chart given by Penney (1970), can be used to make a preliminary selection of the agitator type, based on the liquid viscosity and tank volume. 

P. Zajdel, M. Pawlowski, G. Subra and J. Martinez, Preliminary selection of 5-HT1A receptor ligands by TLC on plates impregnated with synthetic peptides. J. Planar Chromatogr.-Mod. 

Obviously, no solvent satisfies all these requirements, and the selection of a desirable solvent involves a compromise between these and other factors. When a preliminary selection has been made, a secondary screening can be performed based on simplified calculations of minimum energy requirement, since the capital costs for similar process configurations will not vary too much. 

Preliminary selection of the functional and performance specifications (technical, environmental, safety)... 

Preliminary selection of the supplier Instrument tests (if the technique is new)... 

A typical procedure is shown in Fig 1. Each target is analyzed to define its vital components, and a preliminary selection is made of weapons... 

The literature of optimum sequencing of columns is referenced by King (1980, pp. 711-720) and Henley and Seader (1981, pp. 527-555). For preliminary selection of near optimal sequences, several rules can be stated as guides, although some conflicts may arise between recommendations based on the individual rules. Any recommended cases then may need economic evaluations. 

Preliminary selection of binder should be made on the basis [44] of such factors as ... 

These six topics, together with introductory material (Chapter 1) and considerations on agglomerate strength (Chapter 2) comprise the eight chapters of the book. Readers looking for information on a specific size enlargement technique can refer directly to the appropriate chapter. If the problem is to find a suitable technique for a new application, however, a preliminary selection procedure is outlined in Chapter 1. 

Thus, batadiaie is first recovered from steam cradced C4 cuts by solvent extraction, an operation that is sometimes facilitated by preliminary selective hydrogenation of the acetylenic compounds. In a number of applications, the raffinate itsdf must undergo similar treatment to rid it of residual dioiefins. The initial cut, after being debutadienized by hydrogenation, can also serve the same purpose. This also applies to catalytic cracker eflluents that are very often directly upgradable, but whose albeit low butadiene content may justify hydrogenation pretreatment for certain uses. 

Initial selection of dryers. Select those dryers which appear best suited to handling the wet material and the dry product, which fit into the continuity of the process as a whole, and which will produce a product of the desired physical properties. This preliminary selection can be made with the aid of Table 12-9, which classifies the various types of dryers on the basis of the materials handled. 

Economics determines whether to use a continuous flow or a batch reactor. Generally, if the residence time is large and the production rate small, select a batch reactor. This relationship is shown in Figure 7.1, which can be used to obtain a preliminary selection of a reactor. When the application is located in overlapping areas or near a boundary, make a careful analysis to determine the most economic choice. 

Many studies employ fixed sets of fragments taken from some libraries containing preliminary selected fragments. Thus, most additive schemes and group... 

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