Materials economic considerations

While the overwhelming bulk of research on and with TSILs has been carried out on imidazolium-based systems, there is little obvious reason for this to remain the case. Rather, due to the relatively higher cost of commercial imidazole starting materials, economic considerations would suggest that future research places more emphasis on less-costly ammonium and phosphonium-based systems. Indeed, it is... 

Economic Considerations. The principal economic consideration is, of course, total installed system cost, including the initial cost of the flow primary, flow secondary, and related ancillary equipment as well as material and labor required for installation. Other typical considerations are operating costs and the requirements for scheduled maintenance. An economic factor of increasing importance is the cost of disposal at the end of normal flow meter service life. This may involve meter decontamination if hazardous fluids have been measured. 

Process Economics. Relative economics of various ceU culture processes depend heavily on the performance of the ceU line in a system and on the cost of raw materials, particularly the medium. Models are usuaUy developed for the various processes using productivity data obtained from smaU-scale experiments (see Pilot AND MiCROPLANTs). Often, for high value products, the process which ensures the shortest time to market may be the process of choice because of other economic criteria. This is especially tme for pharmaceuticals (qv). RehabUity concerns also often outweigh economic considerations in choosing a process for a high value product. 

Economic Considerations. Gum production by Ethyl Corp. is under 20 metric tons per year. Products are sold primarily for use in U.S. and N.A.T.O. naval appHcations. The materials are sold as finished goods, and thus elastomer pricing is not appropriate. Ethyl Corp. has aimounced that it will either divest or exit this business. Atochem has developed their technology and has constmcted a pilot plant to produce aryloxyphosphazenes. 

Since the first application of turbocompressors (Figure 4-1) in large-scale production of nitric acid as a raw material for fertilizers, explosives, plastics, and a variety of other chemical products, the requirements on processes as well as on rotating equipment have become increasingly demanding. Environmental as well as economic considerations have heavily influenced the development of such plants. 

Once this information has been obtained, the cyclic time of the system can be established. This is primarily an economic consideration, and should be reviewed and reevaluated after the initial sizing of the system. Should the initial capital cost of the adsorber be too high, the cyclic time may be reduced to enable use of a smaller system. In general, the larger the system, the greater the overall efficiency, and the less energy that will be spent per pound of material adsorbed. 

Thermoeconomics of LHS systems involve the use of principles from thermodynamics and fluid mechanics and heat transfer. Therefore, thermoeconomics may be applied to both the use of those principles and materials, construction, and mechanical design, and a part of conventional economic analysis. The distinguished side of it comes from the ability to account the quality of energy and environmental impact of energy usage in economic considerations. 

Except for those catalysts subjected to the previously mentioned conditions, which lead to irreversible transformation of the active phase and/or the support material, the HDT catalysts are regenerable [37], Through a systematic and careful procedure, the spent catalyst is unloaded from the reactor and regenerated by specialized companies. The possibility of in situ regeneration is also commercially offered and the decision, on which method would be used, is typically based on economical considerations [38],... 

The phase Na2Sx is sodium polysulfide, a material with a sulfur content of between 3 and 5. The anode reaction takes place at the liquid sodium - (3"-alununa interface. Here sodium atoms lose an electron and the Na+ ions formed enter the conduction planes in the electrolyte. The cathode reaction, which occurs at the interface between the (3"-alumina and the liquid sulfur forms sodium polysulfides. Despite the desirable properties of the cell, technical and economic considerations have acted so as to curtail large-scale commercial production. 

The selection of an isotope separation process including the design of the separative units and the cascade depends principally on engineering and economic considerations. One must consider the amount of product which is desired, choose the starting material, consider energy demand, etc. It comes as no surprise, then, that many different methods have been used for isotope separation. Some of these have been listed in Table 8.1 and a few are discussed in more detail in the material which follows. 

Economic considerations, which lead some nations to give priority to local materials... 

The use of mathematical programming models on an enterprise-wide scale to address strategic decisions considering various process integration alternatives yields substantial benefits. These benefits not only materialize in terms of economic considerations, but also in terms of process flexibility and improvements in the understanding of the process interactions and systems limitations. 

Wear is an economic consideration. Wear resistance generally, but not always, is inversely related to friction level and other desirable performance characteristics within any class of friction material. The objective is to provide the highest level of wear resistance in the normal use temperature range, a controlled moderate increase at elevated temperatures, and a return to the original lower wear rate when temperatures again return to normal. Contrary to common belief, maximum wear life does not require maximum physical and mechanical properties. 

Economic Considerations. For many years, cost appraisal of insulation was based on a publication by I..B. McMillan in ASME Proceedings. December 1926. in which several factors enter into the analysis, as shown in Fig. At present, the cost of money and the costs of materials and labor atv so unstable, that such analyses are of little value except that they do indicate the factors that enter into actual costs to plant management. 

Consider general ways in which the design criteria can be achieved, specification of other types of equipment, manufacturer s data, economic considerations, materials and fabrication requirements for the design, etc. 

A complete design includes consideration of all aspects of the equipment specification such that the item could be built and operated. These aspects include the mechanical design, materials selection, fabrication requirements, operational details, safety features, versatility (e.g. turn down), economic considerations, etc. The scope (i.e. depth) of the design should be clearly specified by the supervisor. 

Economic considerations If the system is a corrosive environment, a rupture disc with the more exotic and corrosion-resistant material can be selected upstream and downstream of the SRV. It acts as the barrier between the corrosive system and the relief valve. 

---