Space requirements

Space appropriate for the samples being analyzed is required for sample preparation (e g., drying, weighing, encapsulation). For all samples, contamination must be avoided. In some cases a clean room may be necessary. In other cases, a special fume hood may be appropriate. 

A counting room for detector systems and a room for the storage of irradiated samples are also required. The size of the rooms will depend on the extent of activities. 

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The description of chemical reactions as trajectories in phase space requires that the concentrations of all chemical species be measured as a function of time, something that is rarely done in reaction kinetics studies. In addition, the underlying set of reaction intennediates is often unknown and the number of these may be very large. Usually, experimental data on the time variation of the concentration of a single chemical species or a small number of species are collected. (Some experiments focus on the simultaneous measurement of the concentrations of many chemical species and correlations in such data can be used to deduce the chemical mechanism [7].)... 

Some industrial processes produce predorninately latent air conditioning loads. Others dictate very low humidities and when the dew point falls below 0°C, free2ing becomes a major concern. Dehydration equipment, using soHd sorbents such as siUca gel and activated alurnina, or Hquid sorbents such as lithium chloride brine and triethylene glycol, may be used. The process is exothermic and may require cooling the exiting air stream to meet space requirements. Heat is also required for reactivation of the sorbent material. 

Comparing two or more complex alternatives is more difficult than examining equipment capacity or first cost. Characteristics of alternatives should be weighted for relative importance and measured on a common scale to aEow proper evaluation. Many characteristics such as first cost, capacity, space requirement, and annual energy use can be measured objectively and used for system comparisons. Experience has shown that items such as maintenance expense, component life, and downtime can also be rehably estimated. Other factors, eg, system maintainabEity, flexibEity, and comfort, are more arbitrary. 

The space required for a pilot plant varies tremendously with its size and type. A small unit may require only part of a laboratory (perhaps 5—10 m ), whereas an average pilot plant of 50,000 to 200,000 may require a large room or building (perhaps 500—2000 m ), excluding extended feed or product storage. 

Site plan is a scaled drawing, including the roadway system for adjacent areas and auxiUaries and the space requirements for the processing faciUty. 

The layout specialist should be aware of any special space requirements for a pump. Otherwise, pumps are usually fitted into a small area normally considered adequate for a general pump service. Sump pumps and other special types of appHcations need to be called out. 

The heating surface usually determines the evaporator cost and the vapor head the space requirements. The vapor—Hquid separator must have enough horizontal plan area to allow the bulk of the initial entrainment to settle back against the rising flow of vapor and enough height to smooth out variations ia vapor velocity and to prevent splashing directly iato the vapor outlet. Separators are usually sized on the basis of the Souders-Brown expression ... 

Bearing type Load capacity Suitable direction of rotation Tolerance of changing load/speed Tolerance of misalignment Space requirement... 

AOC provide the additional advantages of reducing ground-space requirements and piping and pumping requirements and of providing smoother column operation. 

Ground area and. space requirement.s. Comparisons of the overall space requirements for plants using air cooling versus water cooling are not consistent. Some air-cooled units are installed above other equipment—pipe racks, shell-and-tube exchangers, etc. Some plants avoid such inst ations because of safety considerations, as discussed later. 

Wire-bound wood boxes (typical loads, 1 to 2 tons) have limited use for chemical produc ts. The box body, consisting of thin wooden slats held in place by steel wire twisted around each at, is fastened to a solid-deck wood pallet. The top also consists of wire-bound wooden pieces. A PE liner protects the product and prevents it from falling through the slats. Disadvantages of the container are the labor needed for setup and the space required for knocked-down boxes. Since manufacturers are usually near sources of hardwood, shipping costs to users may be high lead times of 3 to 4 weeks are common. 

Gaskets are veiy important, since thev not only keep the streams separated and prevent leaks from the cell, they have the manifolds to conduct feeds. Doth concentrate and diluate, built into them. No other practical means of feeding the stack is used in the veiy cramped space required by the need to keep cells thin because the diluate has veiy low conductivity. The manifolds are formed by ahgning holes in membrane and gasket. 

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