Batch comparison

Product variability can be reduced through constant monitoring, either by SPC once enough batches have been manufactured, or through batch-to-batch comparisons of data. Where a specification range has been established, whether for an analytical method or a manufacturing process, it is very important to observe fluctuations and drifts in any direction. This is an easy and practical indicator that enables QA to anticipate potential product quality issues before they actually arise. 

Impurity profiles for new batches, comparison to previous (Ames) batch(es)... 

If, however, alternatives are to be compared which are very different in nature, such as a comparison between batch and continuous operation, some allowance for the difference in labor costs must be made. 

Eigure 2 shows that even materials which are rather resistant to oxidation ( 2/ 1 0.1) are consumed to a noticeable degree at high conversions. Also the use of plug-flow or batch reactors can offer a measurable improvement in efficiencies in comparison with back-mixed reactors. Intermediates that cooxidize about as readily as the feed hydrocarbon (eg, ketones with similar stmcture) can be produced in perhaps reasonable efficiencies but, except at very low conversions, are subject to considerable loss through oxidation. They may be suitable coproducts if they are also precursors to more oxidation-resistant desirable materials. Intermediates which oxidize relatively rapidly (/ 2 / i — 3-50 eg, alcohols and aldehydes) are difficult to produce in appreciable amounts, even in batch or plug-flow reactors. Indeed, for = 50, to isolate 90% or more of the intermediate made, the conversion must... 

Fig. 23. Comparison of continuous (cstr) and batch anionic production of SAMS.

Table 1. Flux Comparisons Between Batch and Staged Systems Operating on Cheese Whey...

Product Recovery. Comparison of the electrochemical cell to a chemical reactor shows the electrochemical cell to have two general features that impact product recovery. CeU product is usuaUy Uquid, can be aqueous, and is likely to contain electrolyte. In addition, there is a second product from the counter electrode, even if this is only a gas. Electrolyte conservation and purity are usual requirements. Because product separation from the starting material may be difficult, use of reaction to completion is desirable ceUs would be mn batch or plug flow. The water balance over the whole flow sheet needs to be considered, especiaUy for divided ceUs where membranes transport a number of moles of water per Earaday. At the inception of a proposed electroorganic process, the product recovery and refining should be included in the evaluation to determine tme viabUity. Thus early ceU work needs to be carried out with the preferred electrolyte/solvent and conversion. The economic aspects of product recovery strategies have been discussed (89). Some process flow sheets are also available (61). 

A useful classification of lands of reaclors is in terms of their concentration distributions. The concentration profiles of certain limiting cases are illustrated in Fig. 7-3 namely, of batch reactors, continuously stirred tanks, and tubular flow reactors. Basic types of flow reactors are illustrated in Fig. 7-4. Many others, employing granular catalysts and for multiphase reactions, are illustratea throughout Sec. 23. The present material deals with the sizes, performances and heat effects of these ideal types. They afford standards of comparison. 

High or ultrahigh product purity is obtained with many of the melt-purification processes. Table 22-1 compares the product quality and product form that are produced from several of these operations. Zone refining can produce very pure material when operated in a batch mode however, other melt ciystallization techniques also provide high purity and become attractive if continuous high-capacity processing is desired. Comparison of the features of melt crystalhza-tion and distillation are shown on Table 22-2. 

At first, the reaction was investigated in batch mode, by use of different ionic liquids with wealdy coordinating anions as the catalyst medium and compressed CO2 as simultaneous extraction solvent. These experiments revealed that the activation of Wilke s catalyst by the ionic liquid medium was clearly highly dependent on the nature of the ionic liquid s anion. Comparison of the results in different ionic liquids with [EMIM] as the common cation showed that the catalyst s activity drops in the order [BARF] > [Al OC(CF3)2Ph 4] > [(CF3S02)2N] > [BFJ . This trend is consistent with the estimated nucleophilicity/coordination strength of the anions. 

Methods are available for the determination of relative abrasion resistance using either a mixed jet of air and abrasive, as recommended in the appropriate British Standard or an abrasive wheel or disc. Owing to variations in the quality of the abrasive, and the performance of individual jets, a standard comparison sample is included in each batch. 

Due to these advantages the overall production costs for the immobilised continuous process were found to be 40% lower than that of the batch process. In Figure A8.6 a comparison is given between the batch process costs and the continuous production costs. 

Figure A8.6 Economic comparison of batch and continuous production of L-amino acids using amino acylases.

B8. Batch, J. M., and Hesson, G. M., Comparison of boiling burn-out data for 19-rod bundle fuel elements with wires and warts, HW 80391, G. E. Hanford Lab., Richland. Washington (1964). 

Relyea, J.F. Serne, R.J. "Controlled Sample Program Publication Number 2 Interlaboratory Comparison of Batch Kj Values", Report PNL-2872, Battelle Pacific Northwest Laboratory, 1979. 

The styrene conversion versus reaction time results for runs in the laminar flow regime are plotted in Figure 8. Both the rate of polymerization and the styrene conversion increase with increasing flow rate as noted previously (7). The conversion profile for the batch experimental run (B-3) is presented as a dashed line for comparison. It can be seen that the polymerization rates for runs with (Nj e e 2850 are greater than the corresponding batch polymerization with a conversion plateau being reached after about thirty minutes of reaction. This behavior is similar to the results obtained in a closed loop tubular reactor (7J) and is probably due to an excessively rapid consumption of initiator in a... 

Fig. 7. Comparison between the influence of the addition of TPE to SMA/FR-803 and of TPE/FR-803 master batch to SMA.

Figure 4.23. Comparison of results on four batches using four different methods. The results are grouped according to batch, and within a group, the methods are sulfide precipitation, polarography. X-ray fluorescence, and inductively coupled plasma absorption (left to right).

Fig. 4.41 (n = 12 batches) and 4.42 (n = 46 batches) depict what can and what cannot be gleaned from a detailed study of such cleaned-up tables Unless a connection is fairly obvious, such as between impurities B and C in Fig. 4.42, comparisons can resemble small-talk about the weather, in that there is always a subset of data to prove a given pet notion, and another to disprove it. Why Over the course of a few months a series of insignificant changes in raw materials (a new batch), equipment (higher-capacity steam... 

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