Glycol separation

Pure ethylene glycol freezes at —I2,7°C, Exact composition and temperature for eutectic point are unknown, since solutions in this region turn to viscous, glassy mass that makes it difficult to determine the true freezing point. For the concentrations lower than eutectic, ice forms on freezing, while on the concentrated, solid glycol separates from the solution. 

The gas from the glycol/condensate separator can be used for fuel gas. In many small field gas packaged units this gas is routed directly to fire tubes in the reboiler, and provides the heat for reconcentrating the glycol. This se[>.irator is sometimes referred to as a gas/glycol separator or pump gas separator. 

Accuracy in MS depends on calibration of the mlz axis of the spectra. Calibration is typically performed using separate samples or solutions of the calibrant studied under identical instrumental conditions as the analyte. Calibrants are selected based on the ionization technique and the mlz range required for the analyte typical calibrants used for soft ionization methods with biomolecules include bovine trypsin fragments, bovine insulin (5734 Da), cytochrome c (12,361 Da), horse myoglobin (16,951 Da), lysozyme (14,317 Da), and propylene glycols. Separate solutions of the analyte prepared in the absence and presence of a calibrant species may also be used. Table 15.6 shows typical calibration peaks found with bovine trypsin autolysis fragments.15... 

Figure 7. Distribution of eluate into fractions for product, recycle, and waste forNaCl and glycol separation. 1 1...

Gas chromatography GC, employs a gaseous mobile phase, e.g. nitrogen or helium, and usually a liquid stationary phase, e.g. non-polar Apiezon (alkane grease), OVIOI (polymethyl siloxane) or polar PEG20M (polyethylene glycol). Separation is effected by competition between attraction of the components for the stationary phase and volatility at the column temperature being used, that is, retention forces versus partial vapour pressure in the mobile phase. 

From control studies, we learned that periodate and ethylene glycol, separately and in mixture, behave neither as attractants nor as aversive agents for garter snakes. Treatment of EWW with different concentrations of periodate for 15 minutes at room temperature (RT) resulted in loss of chemoattractant activity at 2.8 mM periodate while at 2.1 mM periodate activity could still be detected. When the reaction time was increased to 1 hour at RT, activity was retained up to 0.83 mM periodate but lost at 1.25 mM periodate (Fig. 8). At 8.3 mM periodate at RT, inactivation was instantaneous. (The periodate concentrations shown in Fig. 8 are the concentrations used prior to dilution with EWW. In the text, final periodate concentrations are used. The equivalent values are, initial concentrations 0.1, 1.0, 10.0, 20.0, 30.0, 40.0, 50.0 mM final concentrations 0.007, 0.04, 0.42, 0.83, 1.25, 1.67, 2.1 mM, respectively.)... 

In gel-ffee sieving systems, the medium consists of an electrolyte solution containing linear hydrophilic polymers (e.g., polyethylene glycols). Separation according to size is obtained because of the resistance provided by entangled polymers. Compared to gel CE, gel-ffee sieving is easy to perform, the capillary system has a long... 

In commercial practice, the monoethylene glycol separation from higher glycols has been carried out in two trayed columns operated in series. The pressure at the bottom of each column is limited to 165 mm Hg absolute by the boiling temperature necessary to avoid product degradation. Each column typically operates at a top pressure of 50 mm Hg absolute and contains 33 actual trays. Each of these trayed columns has a reboiler and a condenser that consume significant amounts of energy. 

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