Scales operating

There are a number of attempts to provide quantitative answers in the htera-ture, but these are generally flawed from either a cost engineering or chemical engineering perspective and their results should be treated with extreme caution. This caveat notwithstanding, it is probably reasonable to say that for most products the threshold hes in the range of 1000—10 000 tonne per year process stream (not product) rate. The threshold value will not, however, be the same for aU products, processes, operating sites, and so on. 

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Scale-Up and Operation Scale-up of pharmaceutical mixer granulators is difficult because geometric similarity is often not preserved. Kristensen recommends constant relative swept volume ratio... 

Lack of BD control High treatment/small boiler Poor design, lead and lag boiler operation scale and ferrous metasilicate FeSi03 Water losses, low inhibitor levels Surging/carryover from high TDS. Excessive TDS in lead boiler. Lack of treatment in lag boiler. 

This case study deals with an industrial Dieckmann condensation (intramolecular ester condensation Scheme 5.6) considering the laboratory and the operation scale. 

Figure 5.9 shows a comparison of the laboratory and operation scale of the production of product 3 (Scheme 5.6). 

Water use is identical in the operation scale and in the literature procedure. If the yield was increased in the hterature protocol simply by applying an extraction procedure, which is not intended in the current recipe, the amount of water needed (always related to one kilogram of product) would be less than in the operational process. Therefore, the currently generated sewage quantity in operation scale appears to be higher than necessary. Since the reduction of waste-treatment costs and the improvement of the environmental performance are... 

Only a little effort is necessary to reduce solvent 1 demand used during reaction scale-up. The quantity used in the laboratory stage was reduced to 59% in the operation stage (Table 5.1). However, related to substrate 2, 96% of solvent 1 is still used. Thus, 87% of the original quantity of solvent will be fed to the incinerator for disposal, while the recycle rate is only 9.1% (from 96% to 87%, Table 5.1). Considering that there is a factor of five difference in solvent 1 demand between the operation scale and the literature procedure (see the segments Solvent of the mass index, in Figure 5.10), the potential for optimiz-... 

Figure 5.10 Mass indices and environmental factors E for the Dieckmann condensation reactions depicted in Scheme 5.5, using software EATOS Laboratory (L) and operation scale (O) in which recycled material is presented separately and a literature protocol (Lit.). ...

In contrast to the quantity of solvent 1 used during the reaction, the quantity of extraction solvent 2 (work up) increases during scale up (Laboratory 100% Operation 103%), especially when it is related to substrate 2 (Laboratory 100% Operation 169%). Compared to the yield obtained from the literature protocol in which an extraction procedure is missing, an efficient extraction seems to be important in order to achieve sufficient product accumulation. However, as the mass index and the environmental factor demonstrate with respect to the possibility for reducing the volume of water used (see above), solvent 2 demand should be able to be reduced as well, since less water use means less solvent is required for extraction. StiU, at least the recycle rate of solvent 2 is as high as 72.8% (from 169% to 46%, Table 5.1), regarding the current data of the technical operation scale. 

The production of the agrochemical 6 (Scheme 5.7) is carried out batchwise via a three-step protocol. Mass balancing has been conducted for three stages of development Laboratory-, pilot- and operation scale. An LCA was available for the operation stage only. A description of this LCA including data sources and data acquisition methods was published by Geisler et al. (product A in reference [9] corresponds to product 6 here). Many parameters in the Life-Cycle Inventory (LCI) are estimated, especially utihty demands and yields of processes for the production of precursors. Uncertainty in these estimations was illustrated in a... 

The yield increases by 15 percentage points during scale up to the pilot scale and by about 2 more percentage points in the final process. This improvement is reflected in the demand of 4 and 5, which declines to 80% in the pilot scale and 78% in the operation scale (Table 5.2). The excess of substrates (0.137 kgkg (L), 0.176 kgkg (P), 0.589 kgkg (O), Figure 5.12) can mainly be attributed to sodium hydroxide and hydrochloric acid inputs. 

Figure 5.12 Mass indices and environmental factors E at different process development stages for the synthesis depicted in Scheme 5.7. Separate representation of recycled material for the synthesis shown in Scheme 5.7 on (L) laboratory-, (P) pilot-, and (O) operation scale.

When related to the consumption of substrates 4 and 5, acid and base are used in higher amounts in the operation scale than in the laboratory scale. Still, raw material demand was significantly reduced in absolute figures (not shown for confidentiality reasons). 

Figure 5.13 Solvent demands during the development of a process for the synthesis route in Scheme 5.7. For percentage changes see Table 5.2 (footnote b recycling considered). Due to the introduction of a second solvent in the pilot and operation scale solvent demand is higher than in the laboratory scale (laboratory scale 6.1 kgkg versus pilot scale 10.6 kgkg and operation scale 7.9 kgkg, see also Figure 5.1 0).

Figure 5.15 Fractions of global-warming scores (%) for all substance flows (seeTable 5.2) concerning the operation scale. Corresponding mass metrics of the flows in Figure 5.10 are indicated in parentheses.

The mass-related metrics shown in Figure 5.11 indicate that the amount of a substrate (see also byproduct formation), an auxiliary material for reaction, and of a solvent have to be reduced. The detailed view of the mass indices of the pilot scale, for example, the segments Substrates and Aux (R) and the size of segments Substrates (excess) and Aux (R) of the environmental factor E, deliver the information listed in Table 5.2 108% base and 162% auxiliary (R) are used. The measure to increase base addition for recycling purposes was successful at the expense of 193% base, much auxiliary material Aux (R) was saved in operation scale (reduction from 162% to only 13%). This leads to an overall... 

In some cases, the changes in the recipe from pilot to operation scale are substantial. In Case study 4, the introduction of a second solvent is accompanied by a better yield, at the expense of a five-fold higher sewage production. Consequently, raw material demand to produce one kilogram of product is diminished, and the introduction of a second... 

To establish the operational pH scale, the pH electrode can be cahbrated with a single aqueous pH 7.00 phosphate buffer, with the ideal Nernst slope assumed. As Eqs. (2a)-(2d) require the free hydrogen ion concentration, an addihonal electrode standardization step is necessary. That is where the operational scale is converted to the concentration scale pcH (= -log [H ]) as described by Avdeef and Bucher [24] ... 

Most operations scaled up in the pharmaceutical industry use semibatch (and batch) processing in the general-purpose equipment. Such operations allow for fine control of slow unit operations, for example, reactions needing hours to complete, fermentation, and crystallization, and such fine control may be necessary to ensure high quality and productivity. 

Ceramicrete cures to create final waste forms that are analogs of naturally occurring phosphate minerals. These minerals have been shown to be relatively insoluble over geologic time scales. The final waste form is stronger than typical room temperature, hydraulic cements and performs in the manner of high-temperature fused ceramics. The technology has been evaluated in bench-and operational-scale tests on contaminated wastewater, sedimenL ash, and mixed wastes. 

Operational-Scale Estimates Based on the resnlts of a treatabihty stndy at the ANL-East in Chicago, Illinois, the laboratory prepared a cost estimate for an operational-scale Ceramicrete stabilization system. The hypothetical system wonld treat waste in 55-gal batches at a rate of 3 batches per shift. The capital costs for the system were estimated at 2,000,000. This estimate included the cost of eqnipment design and development (D20934H, p. 15). 

For a highly concentrated product, a large system hold-up volume increases the potential for product loss. For concentration/diafiltration operations, scale-up may require re-optimization of process parameters, especially if membrane capacities are changed. However, every effort should be made to keep recirculation flux constant with similar inlet and outlet pressures. 

In spite of this complexity, a few guidelines can be asserted within a fixed operational scale ... 

Physical models can be as complex as the actual system, except smaller in size. Such a model is called a pilot operation. Usually, such a system is built to experiment with different material formulations, screw geometries, processing conditions and many more, without having to use excessive quantities of material, energy and space. Once the desired results are achieved, or a specific invention has been realized on the pilot operation scale, it is important to scale it up to an industrial scale. Chapter 4 of this book presents how physical models can be used to understand and scale a specific process. 

A term used to distinguish particles having different sizes in the range of about 50-63 (j,m and about 2000 (J,m, and with several subcategories, all depending on the operational scale adopted. 

Operating scale (laboratory vs. industrial) affects the behavior of chemical reaction systems. It is critical that we develop hydrodynamic models for those systems that are scale sensitive. This will require a collaboration between academic and industrial groups to collect data necessary for commercial-scale equipment. Once the hydrodynamic models have been developed and validated, kinetic models can be integrated with them. 

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