Regime Analysis

All the kernels are empirical, or semiempirical and must be fitted to plant or laboratory data. The kernel proposed by Adetayo and Ennis is consistent with the granulation regime analysis described above (see section on growth) and is therefore recommended ... 

Adetayo Ennis [AIChE J, (1997) In press], based on granulation regime analysis. 

Sweere, A. P. J., Luyben, K. Ch. A. M. and Kossen, N. W. F. (1987) Regime Analysis and Scale-Down Tools to Investigate the Performance of Bioreactors. Enzyme Microb. TechnoL, 9, 386-398. 

A. J. Straathof, ). A. Jongejan, and J. J. Heijnen, Understanding the influence of temperature change and cosolvent addition on conversion rate of enzymatic suspension reactions based on regime analysis, Biotechnol. Bioeng. 1999a, 62, 125-134. 

The scale-down approach can be applied both in the case of an existing process and for a new process. In the latter case a process design is made for the new process from available process data, experimental evidence, and rules of thumb. Regime analysis is applied to this process design. Based on the results a further sm l-scale research strategy is developed, and eventually changes are made in the process design. 

In the following ptu-agraphs this approach will be applied to production of an alkaloid from plant cells cultured in a bioreactor. Regime analysis can be performed by comparison of characteristic parameters of the mechanisms involved in the process. Here the characteristic time concept will be used. The characteristic time is a measure for the rate of a mechanism. A fast mechanism has a short characteristic time. Other terms used are relaxation time, process time, or time constant. A time constant is formally only defined for first-order linear processes. Not all mechanisms involved in a plant cell production process are first order, therefore the term characteristic time is used. The characteristic time is defined as the ratio of a capacity and a flow for example, the characteristic time for oxygen transfer to the liquid phase in a aerated bioreactor q.l becomes... 

In active field studies of dynamic dispersivity using special tracers it is acceptable to utilize one well. In such a case water with a tracer first is pumped into the well and after a certain period pumped back out. At that regime analysis of the change in concentration of the tracer in recovered water is conducted. 

Use a combination of regime analysis and a fluid-solid reaction model... 

Simple reasoning will show that nine distributions are possible for reactions of the type /t -h 5 — / -h S. Table 18.3 (adapted from Lilly and Woodley, 1985) lists examples of four types of reactions with a clear indication of the phase(s) in which the different components are present in each case, that is, whether the distribution coefficient m toward the solvent is infinity or zero. For instance, in reaction 1 of the table, reactant A is in the organic phase, and product R is in the aqueous phase. The methods of analysis for all these cases are similar to those described in Chapter 15, but each case will have its own set of material balance equations that must be incorporated in the overall methodology of regime analysis and reactor design described in that chapter. A fuller consideration of them is outside the scope of this treatment. 

Separation deals with the accurate design of experiments for obtaining data on biological and physical phenomena in circumstances where the rates of the biological and physical processes are independent of one another. Macroconversion (macrokinetics) is an ill-defined basis for scale-up, and efforts must be made to avoid the appearance of such data. This is done with the aid of the test of pseudohomogeneity (see Sect. 4.3) and of regime analysis in general (see Sect. 4.2). 

Compare rate constants or, for significant phenomena, characteristic times of changes over the period of interest, and determine hierarchy of individual response time or rate constant ( regime ). Table 4.2 lists possible cases and results of regime analysis in bioreactor operation. 

---