Equipment configuration importance

The economic optimum configuration and operating conditions of CSTR systems depend on a number of parameters. Capital investment in equipment is important, but energy costs and product yield are usually dominant considerations. Of course, the major theme of this book is that these steady-state economics need to be balanced with dynamic controllability... 

Laboratory experiments using rodents, or the use of gas analysis, tend to be confused by the dominant variable of fuel—air ratio as well as important effects of burning configuration, heat input, equipment design, and toxicity criteria used, ie, death vs incapacitation, time to death, lethal concentration, etc (154,155). Some comparisons of polyurethane foam combustion toxicity with and without phosphoms flame retardants show no consistent positive or negative effect. Moreover, data from small-scale tests have doubtful relevance to real fine ha2ards. 

Dynamics of Process Measurements Especially where the measurement device is incorporated into a closed loop control configuration, dynamics are important. The dynamic characteristics depend on the nature of the measurement device, and also on the nature of components associated with the measurement device (for example, thermowells and sample conditioning equipment). The term mea-.sui ement system designates the measurement device and its associated components. 

The first step in space planning should be to estimate how much bench space wall be required. Benches must accommodate various pieces of permanently installed equipment and still have room for both frequently performed and special one-time tasks. Benches may be either installed against the wall or placed back to back in peninsulas or islands. The exact configuration will be worked out later. For now, what is important is the total number of running feet of bench space that will be required. 

Careful selection of equipment used to carry out chromatography is as important as the selection of the technique itself. Flexibility, ease of manipulation and ability to automate are important. Different techniques have different requirements for column configuration, all require the maximum throughput for process efficiency and economy, and benefit from automation of the individual process steps. 

It is important to note that the small-scale agitator operations may be described in terms of impeller diameter and agitator speed, while manufacturing process equipment is more conveniently specified by horsepower and fluid velocity. For most standard turbine configurations, power number correlations are available to convert impeller diameter and agitator speed into a horsepower value for given fluid properties. Most laboratory bench equipment is designed to provide a torque measurement that can be readily converted to horsepower directly from the conditions of the pilot batches. 

Port Selector Valve. The inside of the Model 50 Extractor oven was originally equipped with a VALCO 4-port selector valve (Model No. E04). This valve is important in operations regularly utilizing additional co-solvents, inerts or vacuum, as in the introduction of modifiers in our case. When the valve is mounted in its normal fashion, one inlet port controls the flow to four outlet ports which are user selected by position number. When the valve is mounted in a reverse fashion, four inlet ports control the flow to one outlet port. In this manner, the inlet ports can be used to independently deliver various solvents. This reverse configuration is used in our system design. With this configuration, multiple fluids can be introduced to the extraction vessels with ease. 

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