Dry fractionation

The hardware items with which the processes described in Section 10.1 are achieved are called facilities, and are designed by the facilities engineer. The previous section described the equipment items used for the main processes such as separation, drying, fractionation, compression. This section will describe some of the facilities required for the systems which support production from the reservoir, such as gas injection, gas lift, and water injection, and also the transportation facilities used for both offshore and land operations. 

Stir with 1000ml 50mM NajCOj + 20mM NaBH4 (pH 10.8) for 16h at 1 C. Filter on G3 glass filter, wash residue with water, bring filtrate to pH 5 with 2M acetic acid, dialyse, concentrate, fteeze-dry Fraction N1... 

Dried fractions should be white. The proportions recovered by the different chemical treatments will be different, depending on the composition of the cell walls however, traditionally, most of the pectic polysaccharides are extracted in the water-soluble fractions (during cell wall isolation), CDTA, and sodium carbonate fractions, but a small proportion is often found in the final residue. Hemicelluloses are usually extracted by 1 M and 4 M KOH. The final residue is predominantly cellulose. 

Hedman, B., Burvall, J., Nillson C. and Markfund S. (2005). Emissions From Small-Scale Energy Production Using Co-Combustion of Biofuel and the Dry Fraction of Household Waste. Waste Management, 25, 311-321. 

Distillation is carried out for many reasons concentration of a substrate in a solvent, removal of one solvent from a mixture and often its replacement by another, azeotropic removal of unwanted solvents (very frequently azeotropic drying), fractionation to separate a pure soivent for reuse, and removal of a low-boiling product of a reaction frequently to prevent its further reaction with the initial substrates or product (e.g., removal of water by passing a wet distillate through molecular sieves). 

In a 250 ml three-necked flask was placed (dichloroiodo)benzene (7.25 g, 30 mmol) with light protection, under nitrogen. Then 2,3-dimethylbutane (30.25 g, 350 mmol) and trihexylborane (400 mg, 1.5 mmol) were introduced by syringes through a septum inlet. The mixture was stirred at room temperature for about 2 h during the reaction hydrogen chloride evolved was carried into an aqueous sodium hydroxide solution by a weak stream of nitrogen. The reaction mixture was neutralized with dilute sodium hydroxide, washed with water several times and dried. Fractional distillation afforded 2-chloro-2,3-dimethylbutane (3.22 g, 89%), b.p. 109-110°C. 

Breitschuh, B. 1998. Continuous Dry Fractionation of Milk Fat - Application of High Shear Fields in Crystallization and Solid - Liquid Separation. Ph.D. Thesis. Swiss Federal Institute of Technology, Zurich. 

Dry fractionation involves melting the milk fat, controlled cooling and crystallization of molten milk fat while cooling to or at a desired temperature and separation of the crystals from the liquid phase. The process is attractive because of its simplicity, relatively low costs and ability to select between fractions based on the melting or functional properties of the fats, which is usually the reason for fractionation. It does not involve the use of solvents, detergents or other additives and furthermore, the desirable flavor notes are not lost although they are partitioned differently between the various fractions. 

Dry fractionation is the most commonly used method in industry for fractionation of milk fat. After a decade of rapid growth to an installed capacity of over 800 tonnes/day in 1990 (Versteeg et al., 1994), with plants in Belgium and several other European countries, growth to 2005 has been... 

The main commercial fractionation process for milk fat is the Tirtiaux process, followed by the De Smet process. There are also some proprietary variations of the dry fractionation process which enable the production of various milk fat fractions. The characteristics of the fractions obtained are affected by many factors, including the equipment design, the associated process, the initial temperature of the molten fat, the crystallization conditions (e.g., degree of initial supercooling), the rate of subsequent cooling and agitation after crystallization commences, the final temperature of fractionation and the method used to separate the fractions. 

One of the attractions of dry fractionation of milk fat is that fractions with tailored melting properties can be made by choosing the fractionation conditions. Similar fractions can be produced from hard and soft milk fat, but the relative yields may differ significantly. 

Despite the benefits of faster crystallization rates and better efficiency compared to dry fractionation (Schaap and van Beresteyen, 1970 Wright et al., 2000b Illingworth, 2002), crystallization of milk fat from a solvent has not been carried out on an industrial scale. Some of the hurdles to the uptake of solvent fractionation technology are the impaired flavor of the milk fat fractions, the cost of the operation, and toxicological and environmental concerns. 

The fractions obtained by supercritical CO2 extraction are different from those by dry fractionation. There are differences in the fatty acid and triacylglycerol compositions and melting profiles (Table 8.1). As the characteristics of the fractions depend on the conditions of the processes and the number of fractions obtained, any comparison between fractions should take into account not only the type of processes employed but also the specific process conditions. 

Dry fractionation is defined as crystallization from a melt without dilution with solvent (O Brien, 1998 Anderson, 1996 Bailey, 1950). This process is the simplest and least expensive process for separating high and low-MP fatty derivatives (Illingworth, 2002 Kellens and Hendrix, 2000 O Brien, 1998 Anderson, 1996 Krishnamurthy and Kellens, 1996). It is also the most commonly practiced form of fat fractionation technologies currently in use (Illingworth, 2002 O Brien, 1998). 

Cold flow properties of liquid fractions obtained from dry fractionation of SME and FAME derived from tallow (TME) and used cooking oil (UCOME) are summarized in Table 1.5. These results showed that dry fractionation... 

Tirtiaux, A., Dry fractionation A technique and an art, in World Conference Proceeding Edible Fats and Oils Processing Basic Principles and Modem Practices, D.R. Erickson (Ed.), pp. 136-141, AOCS, Charrpaign, IL, 1990. 

RP-HPLC Step D Dried fractions were further purified using the same 1090 chromatograpn and a Vydac 218 TP54 C-18 colunm (Separations Group) with a linear gradient from 10 to 50% acetonitrile (0.1% v/v TFA) over 1 hr at... 

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