Process economy

In order to scale up the transaminase-catalyzed chiral amine production process, process economics is an important aspect with scientific and technical aspects involved. In a given transaminase process, the cost of a product or production cost can be expressed in a simplified form as follows [1]. 

Fixed raw materials cost - - enzyme cost + processing cost 

The overall yield of the process is a function of enzyme loading, reaction time, and thermodynamic limitations. The processing cost can be expressed as a function of cycle time and the cost of equipment used to conduct and process the reaction streams. With this information, the following approaches can be appUed toward finding the optimum conditions for carrying out transaminase reactions to reduce the overall cost of production. 

1) If the thermodynamics of the process favors the formation of products in asymmetric synthesis reaction, it is possible to convert prochiral ketone to corresponding chiral amine and obtain high overall yield on prochiral ketone. 

2) If the thermodynamics of the process does not favor the products in asymmetric synthesis, it is possible to achieve reasonable conversions and drive the reaction toward the product by adding excess amine donor in the reaction. The amount of excess amine donor used is dictated by the aminotransferase tolerance to amine donor. 

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Y.-C. Yen and C.-S. Liu, Pthjlene Oxide j Propylene Oxide, Process Economies Report 2D, Stanford Research Institute, Menlo Park, Calif., 1985. 

Terminal Stream Compositions and Quantities These are basically linked to an arbitrary given the produc tion capacity of the leaching plant (rate of extrac t production or rate of raw-material purification by extrac tion). When options are permitted, the degree of solute remov and the concentration of the extrac t stream chosen are those that maximize process economy while sustaining conformance to regulatory standards. 

Until Jenike developed the rationale for storage-vessel design, a common criterion was to measure the angle of repose, use this value as the hopper angle, and then fit the bin to whatever space was available. Too often, bins were designed from an architectural or structural-engineering viewpoint rather than from the role they were to play in a process. Economy of space is certainly one vahd criterion in bin design, but others must be considered equally as well. Table 21-14 compares the principal characteristics of mass-flow and funnel-flow bins. 

Although the viscosity of the sample solution may affect the resolution, for practical reasons highly concentrated protein samples will give the best separations in the case of SEC with respect to the process economy. Although the actual loading capacity depends on the separation problem and on the... 

All of these points contribute to a better process economy than the classical process offers. UOP estimates the cost of a plant (50,000 t/a LAB capacity) with Pacol plant, DeH-9 as catalyst, DeFine- and Detal step at around 45 million. Compared to the first plants with similiar capacities of the early 1980s, in which... 

Another favorable aspect of these polymers is their conformity with the principles of green chemistry. The latter sets guidehnes for the chemical industry in order to secure sustainable development, while increasing process economy [3,4]. Briefly, green chemistry, and the related green engineering [5] call for an increase in, and/or upgrading of ... 

Process economy, by preventing waste generation. This represents a much superior approach to waste treatment ... 

Another important issue is process economy. Some general statements on this topic can be made that are valid for all production systems ... 

It is obvious that a residue catalyst must be optimized in order to get optimum process economy. The contradiction between the recommendations for optimum... 

On the other hand, once one has melt flowing into the mold, one would like the fastest possible reaction to produce final cure and a short process cycle for maximum process economy. This clearly means high reactivity. 

These reaction rates are very important to the process economy for both hill and partial hydrogenation of triglycerides. 

Boron carbide is also a very light and strong material. It can be prepared by reacting carbon yam with BClj and H2 at high temperatures, i.e. a CVD process (Economy and Lin, 1977). The chemical reaction involved is... 

In the academic laboratory, practicality is typically the most important consideration. Because the amounts of substances used are usually small, hazardous materials can be handled by using fume hoods, safety shields, and so on expense, although always a consideration, is not a primary factor. However, for any industrial process, economy and safety are critical. In industry, containers and pipes are metal rather than glass, and corrosion is a constant problem. In addition, since the progress of reactions cannot be monitored visually, gauges must be used. 

The processes being developed at PNL convert the commercial high-level wastes to glasses or related ceramic forms. These materials offer the best practicable immobilization of radioisotopes, in a highly concentrated form, available today the AEG is also sponsoring continuing research on potentially more advanced solidified waste forms which may become available at a later date and offer added increments of safety or processing economy. 

The design objective for the solvent-based purification process is to not only satisfy the process-product specifications, but also to have a good economic return and reliability of performance. The key to success in this case is not only the process design, but also the effect of solvent selection on the process economy, process operability and the environmental impact. In this work, a systematic methodology integrating the solvent (design) selection issues with the extractive separations issues, the process economy and industrial operational as well as environmental constraints. 

The performance of the solvents were checked through solvent-free driving force diagrams for different choices of the property models. Figure 2 shows the solvent-free driving forces obtained for the same systems with the original UNIFAC-VLE model and the UNIFAC-Do model [5]. As solvent AEl (acyclic-ester-1) appears to have desired predicted behavior with both models, it is selected for further studies. One important point of difference is the predicted values of Dy (see Figures 2a-2b). With the UNIFAC-VLE model, it is 0.045 while with UNIFAC-Do, it is 0.145. Therefore, experimental verification is necessary to establish the true value and a sensitivity analysis to determine the solvent property effects on process economy needs to be checked before a decision for pilot plant studies can be made. 

On-line optimization must cope with the variabihty of the process conditions, originated by disturbances that significantly affect the process economy. 

In any commercial application, the process economy depends mainly on catalyst life cycle which in turn is a function of catalyst metal retention capacity. The experimental tests have shown that INT-RI catalyst is able to accept a metal content equivalent to 100% without losing significant catalytic activity. Nevertheless, these results guarantee a stable operation with... 

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