Concentrate processing comparison with other methods

Solvent removed from water by air stripping is recovered by adsorption on AC as the air leaves the stripper. Alternative methods of removing solvent from air are described in Chapter 2. If air stripping is used to clean water for discharge, the air leaving the process usually has a fairly low solvent concentration in comparison with other processes which give rise to solvent-rich air. This is especially true of any batch process for air stripping which is likely to aim to reduce the solvent content of the water to less than 100 ppm (w/w) and, in many cases, down to 20 ppm. 

Internal reflection spectroscopy is widely applied for on-line process control. In this type of application, the chemical reactor is equipped with an internal reflection probe or an IRE. The goal of this type of application is the quantification of reactant and/or product concentrations to provide real-time information about the conversion within the reactor. In comparison with other analytical methods such as gas chromatography, high-pressure liquid chromatography, mass spectrometry, and NMR spectroscopy, ATR spectroscopy is considerably faster and does not require withdrawal of sample, which can be detrimental for monitoring of labile compounds and for some other applications. 

Recently a simplified process was developed for incorporating l-methionine directly into soy proteins during the papain-catalyzed hydrolysis (21). The covalent attachment of the amino acid requires a very high concentration of protein and occurs through the formation of an acyl-enzyme intermediate and its subsequent aminolysis by the methionine ester added in the medium. From a practical point of view, the main advantage of enzymatic incorporation of amino acids into food proteins, in comparison with chemical methods, probably lies in the fact that racemic amino acid esters such as D,L-methionine ethyl ester can be used since just the L-form of the racemate is used by the stereospecific proteases. On the other hand, papain-catalyzed polymerization of L-methio-nine, which may occur at low protein concentration (39), will result in a loss of methionine because of the formation of insoluble polyamino acid chains greater than 7 units long. 

During the 1960 s, reverse osmosis was compared with other methods of demineralization. It was indicated in these comparisons that reverse osmosis could not compete favorably with ion exchange at dissolved solids concentrations below 700 mg/fi and that its most favorable area of use would be from about 1,200 to 5,000 mg/6 dissolved solids. This idea has been totally refuted because some of the most successful applications of reverse osmosis, particularly as part of the process to produce high purity water, have been in treating low dissolved solids water. Water containing 200 mg/ dissolved solids or less has been treated at costs equal to or lower than those of ion exchange alone. 

The efficiency of defibrillation in the ultrasonic process is dependent on power, concentration, temperature, size of fibers, time and distance from probe tip to collector [77]. In some cases, researchers have been used a combination of ultrasonication with other methods to increase fibrillation of nanoscale cellulose. For example, Li et al. [78] prepared nanocrystalline cellulose by ultrasonication and acid hydrolysis with H SO from bleached softwood pulp. They found that ultrasonication led to folding and erosion of the cellulose surface, and thus provided more reactive site to penetrate acid and prepare high-crystalline and small-size nanocellulose. Furthermore, Wang and Chen [77] reported that a combination of ultrasonication and homogenization boosts uniformity and fibrillation of cellulose nanofiber in comparison to ultrasonication solely. In addition, when compared to mechanical blender, ultrasonic bath and ultrasonic probe, Mishra et al. [79] concluded that TEMPO-oxidized fiber treatment with ultrasonic probe was more efficient for nanocellulose production than the other three methods. 

In the following table the important process steps (Proc. no.), the process description (Process quantity) (measure), the related target data (Target data) and their tolerances (tolerances) are listed and compared with average data measured in three runs (Ave. act. data) and the minimum and maximum data measured in the three runs (min./max.). The last two data have to be taken from the protocols and to be listed. In the last column the identification number of the runs, in which the two extreme data are measured is listed (Ident. no.) The last two column are not given, with the exception of proc. nr. 1.1 as an example- The table is a proposal of how the comparison could be made. The list may not be complete in all possible cases and is concentrated on the time-, pressure- and temperature data. Other methods may be preferred to make the ability of the equipment transparent. 

---