Economically feasible process

Fused-salt electrolysis of K2NbFy is not an economically feasible process because of the low current efficiency (31). However, electrowinning has been used to obtain niobium from molten alkaU haUde electrolytes (32). The oxide is dissolved in molten alkaU haUde and is deposited in a molten metal cathode, either cadmium or zinc. The reaction is carried out in a ceramic or glass container using a carbon anode the niobium alloys with the cathode metal, from which it is freed by vacuum distillation, and the niobium powder is left behind. 

Advantages Cement-based solidification systems are an economically feasible process having the following advantages ... 

The motivation for the vast majority of radiation chemical studies has been provided by considerations other than the desire to develop economically feasible processes. The approach has been fundamental, with the result that many data exist on systems having no possible application in the chemical process industry, while data on potential systems are lacking. Though extensive work on aqueous systems has been motivated by practical applications of these data to corrosion problems and biological systems, the approach has still been a fundamental one and the systems studied have been chosen so as to yield information... 

In order to improve this reaction, a proper understanding of all parameters affecting product yield is desired. Clearly, the high enzyme consumption is a major obstacle for an efficient and economically feasible process. A likely cause of the inefficient use of DERA in this conversion is enzyme deactivation resulting from a reaction of the substrates and (by-) products with the enzyme. In general, aldehydes and (z-halo carbonyls tend to denature enzymes because of irreversible reactions with amino acid residues, especially lysine residues. From the three-dimensional structure it is known that DERA contains several solvent-accessible lysine residues [25]. Moreover, the complicated reaction profile as shown in Scheme 6.5 indicates the potential pitfalls of this reaction. 

As the extruder is a reactor with a relatively expensive volume, the residence time needed for the reaction should be short. Therefore, the reaction kinetics must be sufficiently fast to acquire an economically feasible process. 

The body of scientific knowledge behind food fabrication started to accumulate less than 50 years ago. It has been in the last 20 years that the study of foods as materials has become a field in its own. It has been fostered by advances in related areas, most notably polymer science, mesoscopic physics, microscopy, and other advanced physical techniques. Progress in separations science has led to economically feasible processes that make available refined and functional food ingredients that replace or complement traditional raw materials. New technologies, most notably the use of membranes and microdevices, promise to bring the scale of fabrication closer to that of micro structural elements in dispersed phases (droplets, bubbles). 

Economically feasible processes for biomass conversion to ethanol requires the fermentation of the sugars generated in the pretreatment and hydrolysis steps. In agricultural residues and hardwoods, xylose constitutes about 45% of the total sugars, and therefore xylose conversion to ethanol is important for high yields. Dilute acid hydrolysis of cellulosic biomass generates inhibitory compounds such as furfural, hydroxymethyl furfural, and acetic acid [1], These inhibitors affect the ability of yeasts to ferment the hydrolyzates, and therefore a detoxification step is usually included in fermenting acid... 

A rough schematic of the acetic acid process [37,38] is shown in Figure 3.10. In addition, to run an economically feasible process, acetic acid is constantly recovered from the respective processing steps and acetic anhydride is manufactured therefrom on site. 

The aim of artificial photosynthesis is to devise an economically feasible process for decomposing water by means of solar energy. One approach involves using a sensitiser S and a relay R which, after oxidation-reduction, generate oxygen and hydrogen from water ... 

There is generally a number of technically feasible processes for any given separation. For example, a solution of common salt can be concentrated by freezing, by evaporation or by reverse osmosis. The skill of a process design team is to select an economically feasible process. The separation of xylenes is a classic example. 

In order to overcome these difficulties and to render the processes economically feasible, processing aids (PAs) are frequently used. PAs eliminate flow instabilities or postpone them to higher flow rates. The end result is an increase of the productivity as well as an energy cost reduction, while high product quality is maintained. 

However, there are also some restrictions in the use of extruders as polymerization reactors and in the type of extruders which can be used. As the extruder is a reactor with a relatively expensive volume, the residence time needed for the reaction should be short. Therefore, the reaction kinetics have to be sufficiently fast to acquire an economically feasible process. In addition, there is a limitation to the reactions which can be performed in the extruder based on the heat of reaction and the viscosity reached. If the reaction enthalpy is very large, the temperature rise in the extruder is too large to control. Moreover, the viscosity of the reaction product has to be sufficiently high to be able to transport the material and to make the use of an extruder profitable. 

An economically feasible process for industrial cellulosic ethanol production requires a high titer ethanol process due to the high energy demands of ethanol distillation [99]. In addition, increasing the final ethanol titer would have a significant effect on lowering capital costs due to the reduced size of the... 

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