Scaleup experiments

Doki, N., Kubota, N., Sato, A., Yokota, M., Hamada, O. and Masumi, F., 1999. Scaleup experiments on seeded batch cooling crystallization of potassium alum. American Institution of Chemical Engineers Journal, 45(12), 2527-2533. 

Figure 2. Autoclave used in scaleup experiments, showing an internal view with the flow profile.

Effects of Impurities nd Solvent. The presence of impurities usually decreases the growth rates of crystalline materials, and problems associated with the production of crystals smaller than desired are commonly attributed to contamination of feed solutions. Strict protocols should be followed in operating units upstream from a crystallizer to minimize the possibiUty of such occurrences. Equally important is monitoring the composition of recycle streams so as to detect possible accumulation of impurities. Furthermore, crystalliza tion kinetics used in scaleup should be obtained from experiments on solutions as similar as possible to those expected in the full-scale process. 

Contact mixing equipment vendors for a recommended scaleup. They have proprietary correlations and extensive experience on similar scaleups. They... 

One of the best definitions is by Attilio Bisio (1) The successful startup and operation of a commercial size unit whose design and operating procedures are in part based on experimentation and demonstration at a smaller scale of operation. He also points out that Smith (2) argued in 1968 that the starting point for scaleup studies is the ultimate intended commercial unit. The professional should scaledown from the design parameters and constraints of that commercial unit so that the smaller scale experiments were most useful in reducing the uncertainties of the commercial run. Smith wrote that scaleup from small-scale studies is a misleading concept. 

Now our experiment has been designed We will use plastic pipe with an inside diameter of 1.6 in. and length of 50 ft and pump water through it at a rate of 27.5 gpm. Then we measure the pressure drop through this pipe and use our final equation to scaleup this value to find the field pressure drop. If the measured pressure drop with this system in the lab is, say, 1.2 psi, then the pressure drop in the field pipeline, from Eq. (2-13), would be... 

Small steady-state reactors are fiequently the next stage of scaleup of a process from batch scale to full commercial scale. Consequently, it is common to follow batch experiments in the laboratory with a laboratory-scale continuous-reactor process. This permits one both to improve on batch kinetic data and simultaneously to examine more properties of the reaction system that are involved in scaling it up to commercial size. Continuous processes almost by definition use much more reactants because they run continuously. One quickly goes from small bottles of reactants to barrels in switching to... 

A 100-gal pilot-plant reactor is agitated with a six-blade pitched turbine of 6 in diameter that consumes 0.35 kW at 300 rpm. Experiments with acid-base titrations showed that the mixing time in the vessel is 2 min. Scaleup to a 1000-gal vessel with the same mixing time is desired. 

Often, a pilot plant will operate in the viscous region while the commercial unit will operate in the transition region, or alternatively, the pilot plant may be in the transition region and the commercial unit in the turbulent region. Some experience is required to estimate the difference in performance to be expected upon scaleup. 

The one-pot procedure shown in Scheme 7.4 was found to be extremely robust on laboratory scale, but an unexpected problem arose upon scaleup in the pilot plant. Whereas the amidation reaction routinely reached completion within 12 h in laboratory experiments, it was found that 50 hours were required for the reaction to go to completion when carried out on multikilogram scale.24 An initial hypothesis for this unexpected drop in the reaction rate was that carbon dioxide, which is liberated in the CDI-mediated coupling, may play an important role in the reaction. It was postulated that CO2 may be removed more slowly from the large-scale reaction and would be available to react with diamine 18, thereby reducing the rate of the amide coupling. In an attempt to test this hypothesis, imidazolide 23 was prepared and used as the starting material for two parallel amidation reactions. In the first experiment, the reaction mixture was sparged with C02... 

However, each set of factors entering in to the rate expression is also a potential source of scaleup error. For this, and other reasons, a fundamental requirement when scaling a process is that the model and prototype be similar to each other with respect to reactor type and design. For example, a cleaning process model of a continuous-stirred tank reactor (CSTR) cannot be scaled to a prototype with a tubular reactor design. Process conditions such as fluid flow and heat and mass transfer are totally different for the two types of reactors. However, results from rate-of-reaction experiments using a batch reactor can be used to design either a CSTR or a tubular reactor based solely on a function of conversion, -r ... 

The technological importance of butene isomerization and similar experiments with ferrierite by researchers at Shell Amsterdam63,64 have recently been reported. Results of our studies (and scaleup studies at Texaco) have led to the commercialization of n-butene isomerization catalysts by Texaco, Inc. 66... 

LadischI J has worked with a variety of column sizes ranging from 2 to 16 mm in diameter and 10 to 600 cm in length. His experience is that published semi-empirical scaleup correlations are useful in obtaining a first estimate on large scale column performance. 

Scaleup of laboratory data is a critical step and requires considerable experience. Since scaleup is subject to many factors that are not quantifiable, it is based primarily on experience and is a function of the specific dryer. When the heating surface is known, it is easy to calculate the working volume and the dryer s geometrical volume (Fig. 7). 

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

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