Laboratory or Pilot Plant Experiments

The properties of the solids and liquids required to estimate the necessary solid-liquid mixing parameters, including  

In the various correlations presented earlier, the magnitude and sign of the exponents on the variables establish their parametric effects and may be used as a guide for selection of the more sensitive parameters to explore in a laboratory or pilot plant. 

Typical lab experiments must include evaluation of the following effects  

Impeller speed to establish the effect, if any, on the process result as well as the speed beyond which there is no further significant gain in or deterioration of the desired process results 

Particle size to determine the effect on reaction rates for solid-catalyzed reactions in particular, the particle size at which mass transfer effects are negligible 

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Known scale-up correlations thus may allow scale-up even when laboratory or pilot plant experience is minimal. The fundamental approach to process scaling involves mathematical modeling of the manufacturing process and experimental validation of the model at different scale-up ratios. In a paper on fluid dynamics in bubble column reactors, Lubbert and coworkers (54) noted ... 

In the first case, as discussed in Sec. VII below, a retrospective review of multiple batch records can provide considerable insight to support a defined PAR. A similar approach might involve a spreadsheet that summarizes critical parameter values for a series of R D lots when preparing to transfer the technology to R D s production colleagues. Often such retrospective data can be reinforced where gaps occur by some prospective laboratory or pilot plant experiments. 

Direct scaleup from carefully designed laboratory or pilot plant experiments... 

This problem is usually overcmne by basing designs on scale-up from laboratory or pilot-plant experiments. As will be seen later, even if this is done, scale-up is fraught with difficulties because of the emimcal and incomplete nature of the available correlations whidi often bave tmly a tenuous link to the basic mechanisms. Hence the designers tendency to proliferate the standard configurations, optimal or not. 

Ammonia synthesis is one of the most important processes operated by the chemical industry. Modern ammonia synthesis plants can produce up to 1800 tons of ammonia per day. Clearly, the design of the large reactors requires powerful and reliable calculation methods and the availability of a sound kinetic equation is an essential requirement. It is not only necessary for reactor design, but is also required to express catalyst performances generated from either laboratory or pilot plant experiments. 

Based upon laboratory and mini- or pilot-plant experiments process flow-sheets are prepared that also take environmental and safety aspects into consideration. Studies on these aspects are carried out in parallel with chemistry and engineering research in the form of so-called Integrated Process Development (see Heinzle and Hungerbiihler, 1997). 

Batch fermentations result in high product concentration (120-150 kg/m3) but in low productivity (2 kg m Iff1). Dramatic improvements in productivity (20-80 kg m Iff1 in laboratory- and pilot-plant experiments) were obtained by using cell recycle via MF or immobilized cells, at the expense of lactate concentration in the effluent (usually lower than 50 kg/m3). 

Laboratory and pilot plant experiments carried out at INCT showed that reverse osmosis is very useful for the treatment of liquid low-level radioactive wastes from Polish nuclear laboratories. However, to reach high decontamination the process should be arranged as a multistage operation with microfiltration or ultrafiltration pretreatment [32,33]. 

Scale-up from laboratory-scale or pilot-plant experiments to a full-... 

Methods for predicting efficiency also parallel those for tray columns comparison against a similar installation, use of empirical methods, direct scaleup from laboratory or pilot plant, and use of theoretically derived models. Approaches by vendors of packing usually center on comparisons with similar installations (the so-called vendor experience ) and empirical approximations. Direct scaleup from small column studies is difficult with packed columns because of the unknown effects of geometrical factors and the variations of liquid distribution that are required for practical reasons. Theoretical or semitheoretical models are difficult to validate because of the flow effects on interfacial area. It may be concluded that there is no veiy good way to predict packed column efficiency, at least for the random type packings. 

Many experiments oti electrokinetic remediation are carried out on a laboratory or pilot plant scale, with artificially polluted clay media like kaolin. This is because clay soils usually contain a variety of other substances that are present in smaller or trace amounts, such as organic matter, iron oxides, quartz, feldspars, aluminum and manganese hydroxides, titanium oxides, carbonates, and calcite, which could affect electrokinetic response by decreasing the resistance to the flow of water through the sediment [10]. 

Since capturing of these parameters is extremely time-consuming and, despite that, always less effective than an empirical filtration experiment in the laboratory or pilot plant, the latter is in practice normally preferred as the basis for designs [5], or integrated as an indispensable component in the computer programmes described above [6].Figure 18.1 illustrates the schematic construction of an experimental arrangement for lab-scale (test leaf) experiments. 

Experiments show that the measured value of ksL can be significantly different from that estimated with the correlations above (Nienow, 1975). Therefore, for reliable scale-up or design, laboratory- or pilot-plant experimentation to measure the rate of mass transfer is a must for systems where mass transfer is important. 

Identify the predominant rate-controlling mechanism kinetic, mass or heat transfer. Choose a suitable reactor type, based on experience with similar reactions, or from the laboratory and pilot plant work. 

A part of the test plan must include testing for the consequences of equipment malfunction, deviations in process conditions, and human error. Bench-scale equipment, for example, the RC1, is quite suitable for such experiments. By analysis of the process, critical conditions can be defined, which then need to be tested in order to be able to proceed safely from the laboratory to pilot plant studies. In testing abnormal conditions or process deviations, caution is required to assure that no uncontrollable hazard is created in the laboratory. Typical deviations, including impact on the process, are discussed in the following paragraph. 

The solvent extraction process has not yet undergone pilot plant investigation, and all the above estimates are based on small laboratory or bench scale experiments. If further testing under practical conditions substantiates the laboratory observations, it appears that the solvent extraction process definitely has an area of specialization in the over-all saline water conversion program. 

Thus, the shell wall thickness is essentially the same as the head thickness. According to Table 6.2, the minimum wall thickness is 3/32 in (2.38 mm) for high-alloy steels. The application of this rule-of-thumb more than doubles the wall thickness, which should be an adequate corrosion allowance. The selection of a corrosion allowance in the final design must be based on past experience or from laboratory and pilot plant tests. 

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