FULL SCALE PROCESS EXAMPLE

It is normally helpful to break the fermentation process down into several distinct steps and examine the role that mixing plays in these various steps. Then, the total effect on the process result from the combination of these different steps can be examined. 

In looking at the performance of a mixer in a tank with a particular starting concentration of microorganisms, it is possible to determine the kinetics of the antibiotic production which produces the growth of the microorganisms throughout the process. Typical data is shown in Fig. 41 previously. 

This effect must be carefully distinguished in analyzing the use of a higher mass transfer ability agitator, which can take advantage of increased 

It is also common that fermentations made in different parts of the world, although supposedly somewhat similar, because of inherently different conditions of processing can give different results in equipment that is quite similar. 

The use of higher mixer mass transfer abilities can be examined in two 

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The on-line/ at process industry often describes precision and linearity as a percentage of the full scale concentration. Full scale, for example, is the maximum concentration that is expected to be analyzed or the concentration that is equivalent to 20 mA on the 4-20 mA current loop. When used in this work, the term % RSD of full scale is the standard deviation for the results of a sample analysis compared to the full scale value of the range that the analyzer is set for. Standard deviation as a percent of full scale indicates the maximum deviation that can be expected on a sample of any concentration that is within the analysis range. Because % RSD is dependent on the concentration being analyzed, it would have to be determined for each concentration in the range. Percent of full scale is a convenient way to define the precision of an analyzer that allows the maximum anticipated RSD to be inferred for any concentration in the range. See Calculation 1 ... 

Herbst et al. [International J. Mineral Proce.ssing, 22, 273-296 (1988)] describe the software modules in an optimum controller for a grinding circuit. The process model can be an empirical model as some authors have used. A phenomenological model can give more accurate predictions, and can be extrapolated, for example from pilot-to full-scale apphcation, if scale-up rules are known. Normally the model is a variant of the popiilation balance equations given in the previous section. 

Chemical reaction hazards must be considered in assessing whether a process can be operated safely on the manufacturing scale. Furthermore, the effect of scale-up is particularly important. A reaction, which is innocuous on the laboratory or pilot plant scale, can be disastrous in a full-scale manufacturing plant. For example, the heat release from a highly exothermic process, such as the reduction of an aromatic nitro compound, can be easily controlled in laboratory glassware. Flowever,... 

Pilot plant experiments represent an essential step in the investigation of a process toward formulating specifications for a commercial plant. A pilot plant uses the microkinetic data derived by laboratory tests and provides information about the macro kinetics of a process. Examples include the interaction of large conglomerates of molecules, macroscopic fluid elements, the effects of the macroscopic streams of materials and energy on the process, as well as the true residence time in the full-scale plant. 

First of all, the increased computer power makes it possible to switch to transient simulations and to increase spatial resolution. One no longer has to be content with steady flow simulations on relatively coarse grids comprising 104-105 nodes. Full-scale Large Eddy Simulations (LES) on fine grids of 106—107 nodes currently belong to the possibilities and deliver realistic reproductions of transient flow and transport phenomena. Comparisons with quantitative experimental data have increased the confidence in LES. The present review stresses that this does not only apply to the hydrodynamics but relates to the physical operations and chemical processes carried out in stirred vessels as well. Examples of LES-based simulations of such operations and processes are due to Flollander et al. (2001a,b, 2003), Venneker et al. (2002), Van Vliet et al. (2005, 2006), and Flartmann et al. (2006). 

Heat and mass balance equations are used in all aspects of process modelling however, what is key to this model is an understanding of the electrolytic process behind the cell. For example, the model must be able to predict current efficiency and k-factor if it is to predict electricity consumption. Most of these electrolytic parameters are calculated using empirical relationships derived from experimental data both from test cells and the full-scale plant. Considering k-factor, this is primarily a function of brine strength and temperature. Figure 20.5 illustrates the experimentally derived function used in the model. 

When analyzing a chemical reaction process, especially in the scale-up and design stages, the review team must keep in mind some significant differences between the behavior of a chemical system in the laboratory or pilot operation and in a full-scale facility. Reaction rate and process temperature parameters, for example, do not generally scale up directly from the laboratory scale due to reasons such as ... 

Currently the use of full-scale GAC systems in the U.S. petroleum rebning industry is very limited. Some rebneries used GAC as the secondary treatment process but have discontinued the operations. Two examples are the Atlantic Richbeld (Arco) system near Wilmington, CA, and the British Petroleum (BP) system in Marcus Hook, PA [17]. 

An important innovative technique to replace water as the solvent in dyeing processes is the use of supercritical fluids, for example, supercritical CO2 for dyeing processes. Successful trials have been conducted in various scales with different fibers and full-scale production has been performed in the case of PES dyeing [62,63]. Besides the handling of high pressure equipment, the development of special dyestuff formulations is required. 

Since both the direct and phased approaches offer, at least in principle, equal promise for ultimate success (i.e., comprehensiveness and complete characterization), it is worthwhile to examine their relative resource requirements. Several studies were conducted with the objective of comparing the costs of direct and phased (with elimination of low priority streams) sampling and analysis approaches. (2,3] A number of processes were evaluated during these studies and the results for two unit operations — a limestone wet scrubber and full-scale low-Btu coal gasifier — are taken as examples. The scrubber involved seven feed or waste stream sampling sites. The gasifier contained 70 identifiable stream sampling points. The total estimated costs for both processes by both approaches are shown in Table I. 

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