Bench development, principles

Since the first production processes were implemented by Monsanto and Sumitomo in the early 1970s, the number of production processes has grown rather slowly and comprises today (only) about 15 to 20 entries. Of these, 11 are medium to large scale, while all of the others are applied on a scale of 11 y-1 or less, and several of them are no longer in operation. On the positive side, many more processes developed to the pilot or bench scale are, in principle, ready for technical application. 

These examples show the importance of performing bench-scale tests as part of the process and catalyst development, but it also illustrates the importance of applying the pseudo-adiabatic reactor principle to observe the deactivation phenomena and to ensure reliable, adiabatic bench-scale tests when providing data for industrial design. 

Bench top devices are also available to perform complete blood counts (CBC) using analytical principles similar to those used in laboratory-based devices. In addition, single-use cartridge technology is being developed that will have the capability to offer full white cell differentiation. Immunoassay measurements are also now available in a compact device, for use in clinics and similar locations. The Innotrac Aio is an example of such a device and uses... 

After 30-40 years of methodological development and particularly the rapid changes of the last 10 years, many of the routine assays in use in clinical chemistry may be expected to continue in similar form for some time to come. From the standpoint of work study and work simplification, however, techniques are often still far from perfect, but, if the help of a work-study consultant is enlisted, he finds difficulty in giving advice on the simplification of bench techniques because of his lack of knowledge of the scientific principles involved. Clinical chemists must therefore, to a large extent, act as their own work-study consultants. 

To summarize these last examples, we have seen that in the design of reactors that are to be operated at conditions (e.g.. temperature and initial concentration) identical to those at which the reaction rate data were obtained, we can size determine the reactor volume) both CSTRs and PFRs alone or in various combinations. In principle, it may be possible to scale up a laboratory-bench or pilot-plant reaction system solely from knowledge of as a function of X or Q. However, for most reactor systems in industry, a, scale-up proce.s.s cannot be achieved in this manner because knowledge of solely as a function of X is seldom, if ever, available under identical conditions. In Chapter 3. we shall see how we can obtain = yfX) from information obtained either in the laboratory or from the literature. This relationship will be developed in a two-step process. In Step 1, we will find the rate law that gives the rate as a function of concentration and in Step 2, we will find the concentrations as a function of conversion. Combining Steps 1 and 2 in Chapter 3. we obtain -/-.v =JiX). We can then use the method.s developed in this chapter along with integral and numerical methods to size reactors. 

For the requirements of process development and process safety investigation, a bench scale heat flow calorimeter has been developed eind built. Figure 1 outlines its principle. The stirred tank reactor (A) is surrounded by a jacket in which a heat transfer fluid is circulated at a very high rate. A cascaded controller (B) adjusts the temperature of the circulation loop (C) so that heat transfer through the reactor wall equilibrates the heat evolution in the reactor. Injection of thermostated hot or cold fluid is used to adjust the temperature in the loop. 

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