Water dissolved

Leaving the refinery, jet fuel has generally no free water and contains only a small quantity of dissolved water. But humidity from the air and tank breathing result in continuous intrusion of water that must be then removed by decanting and filtration. This is why jet fuel needs to be tested for its ability to separate the contained water. 

For jet fuels, the elimination of free water using filters and coalescers by purging during storage, and the limit of 5 ppm dissolved water are sufficient to avoid incidents potentially attributable to water contamination formation of micro-crystals of ice at low temperature, increased risk of corrosion, growth of micro-organisms. 

To a few drops of formalin solution add a few drops of dinitro-phenylhydrazine reagent A (p. 263) a yellow precipitate is produced in the cold. Acetaldehyde and acetone give orange-coloured precipitates. Dissolve water-insoluble compounds e.g-y benzaldehyde, salicylalde-hyde, acetophenone and benzophenone) in a small volume of methanol before adding reagent B. With benzophenone the precipitate forms slowly. 

Commercial soy protein concentrates typically contain 70 to 72% cmde protein, ie, nitrogen x 6.25, dry wt basis. Soy protein isolates are prepared from desolventhed, defatted flakes. A three-stage aqueous countercurrent extraction at pH 8.5 is used to disperse proteins and dissolve water-soluble constituents. Centrifugation then removes the extracted flakes, and the protein is precipitated from the aqueous phase by acidifying with HCl at pH 4.5. 

R the air—glass reflection coefficient. Transmission is a function of wavelength. In siUcate glasses, it is limited by the absorption of siUca at approximately 150 nm ia the uv and at 6000 nm ia the air. Iroa impurities further reduce transmission ia the uv and near ir. Dissolved water absorbs at 2700 nm and is a serious problem ia making ir transmitting glasses. 

Solid-Bed Dehydration. Sihca gel, bauxite, activated alurnina, or molecular sieves can be used for removing dissolved water to meet propane specifications. The soHd-bed dehydrators are used in a cycHc adsorption process. After an adsorption cycle has completed, the bed is heated with a purge gas or a vaporized Hquid-product stream for regeneration. If the latter is used, the Hquid product is condensed, separated from the free water, and returned to the process. After the beds are regenerated, they are cooled and returned to the adsorption cycle. 

Fractionation. Direct fractionation also can be used to remove dissolved water from LPG. The water-rich overhead vapor from the dryer fractionator is returned to the fractionator as reflux and the water phase is discarded. A dry LPG product that meets either propane or butane water specifications is produced as a ketde product from the fractionator. 

The slope of the water solubiUty curves for fuels is about the same, and is constant over the 20—40°C temperature range. Each decrease of 1°C decreases water solubiUty about 3 ppm. The sensitivity of dissolved water to fuel temperature change is important. For example, the temperature of fuel generally drops as it is pumped iato an airport underground hydrant system because subsurface temperatures are about 10 °C lower than typical storage temperatures. This difference produces free water droplets, but these are removed by pumping fuel through a filter-coalescer and hydrophobic barrier before deUvery iato aircraft. 

Liquids. Liquids (33) are common forming additives in plastic, paste, and slurry processing. In plastic forming operations, the Hquid aids forming and serves as the binder/plasticizer for the system. In pastes and slurries, other additives are also dissolved or dispersed in the Hquid/solvent. Water is a good, inexpensive solvent that can be recycled. Organic Hquids such as alcohols are used to process water-sensitive materials and to dissolve water-insoluble forming additives, however, at considerably more expense. 

Based on Hquid—Hquid equiHbrium principles, a general model of octanol—water partitioning is possible if accurate activity coefficients can be determined. First, phase equiHbrium relationships based on activity coefficients permit Hquid—Hquid equiHbrium calculations for the biaary octanol—water system. Because the two components are almost immiscible ia each other, two phases form an octanol-rich phase containing dissolved water, and a water-rich phase containing dissolved octanol. 

Feed equipment as described for dry alum is suitable for soda ash. Dissolving of soda ash may be hastened by the use of warm dissolving water. Mechanieal or hydraulie jet mixing should be provided in the dissolver. Materials of construetion for piping and accessories should be iron, steel, rubber, and plastics. 

The oils consisting mainly of terpenes do not appear to dissolve water, nor to be soluble in water, or at all events, to any appreciable extent. 

Commercial butane and commercial propane shall not contain free or suspended water on visual inspection. Additionally, for commercial propane, the content of dissolved water shall not be such as to cause failure when tested in accordance with the valve freeze method. 

Volkov (1994) has given a state-of-the-art review on pervaporation. A number of industrial plants exist for dehydration of ethanol-water and (.vwpropanol-water azeotropes, dehydration of ethyl acetate, etc. There is considerable potential in removing dissolved water from benzene by pervaporation. The recovery of dis.solved organics like CH2CI2, CHCI3, CCI4, etc. from aqueous waste streams also lends itself for pervaporation and pilot plants already exist. 

As the concentrations of dissolved water and EDC are small, the best approach to this problem is by successive approximation rather than by setting up and solving equations for the unknown concentrations. 

Even after all ice has been removed by sublimation, the product phase, or freeze concentrate, contains a large amount of dissolved water that must be removed to produce a stable product. This water is removed by desorption during secondary drying. Secondary drying is usually carried out at elevated product temperature to achieve efficient water removal. 

The availability of data on KAW, KoW and KqA raises the possibility of a consistency test. At first sight it appears that KqA should equal K0W/KAW, and indeed this is often approximately correct. The difficulty is that in the case of KAW, the water phase is pure water, and for KqA the octanol phase is pure dry octanol. For KoW, the water phase inevitably contains dissolved octanol, and the octanol phase contains dissolved water and is thus not dry. Beyer et al. (2002) and Cole and Mackay (2000) have discussed this issue. 

There are apparently two sources of this effect. The molar volume of water changes relatively little as a result of the presence of a small quantity of dissolved octanol, however the quantity of dissolved water in the octanol is considerable, causing a reduction in molar volume of the octanol phase. The result is that even if activity coefficients are unaffected, log S0/Sw will be about 0.1 units less than that of log KoW. Effectively, the octanol phase swells as a result of the presence of water, and the concentration is reduced. In addition, when log KqW exceeds 4.0 there is an apparent effect on the activity coefficients which causes log (SQ/SW) to increase. This increase can amount to about one log unit when log Kow is about 8. A relatively simple correlation based on the analysis by Beyer et al. (2002) (but differing from their correlation) is that... 

Field experiments of C02 sequestration into the Ogachi HDR have been examined for 4 years by our group (Metcalfe et al., 2006 Ueda et al.2007). In 2007, C02 dissolved water (river water with dry ice) was directly injected into OGC-2 (Fig.3 Run 1 (from September 2nd to 9th) and Run 2(from September 11th to 16th)). Several tracers were also injected at the same time. Water samples are collected at the depth of ca. 800m by a sampler (500ml in volume) and monitored for their... 

In another estuary near New York, namely the Hudson estuary, NP was analysed by GC-MS. Dissolved water concentrations ranged from 0.012 to 0.094 xg LT1, while the concentrations of NP in the particulate phase of the water amounted to between 0.45 and 4.0 p,g g-1 [16]. 

Emulsions are one of the most important structures prepared specifically for a given application. For example, a day cream (skin cream) has characteristics and ingredients different from that of a night cream. One of the main differences between emulsions is whether oil droplets are dispersed in the water phase, or water drops are dispersed in the oil phase. This can be determined by measuring their conductivity because conductivity is higher for the O/W than for the W/O emulsion. Another useful property is that O/W will dissolve water while W/O will not, thus showing that W/O or O/W may be chosen depending on the application area. Especially in the... 

Ihinger P.D., Zhang Y., and Stolper E.M. (1999) The speciation of dissolved water in rhyolitic melt. Geochim. Cosmochim. Acta 63, 3567-3578. 

Low levels of water, up to approximately 50 to 75 ppm, can be solubilized into most middle distillate fuel at ambient temperature without causing the fuel to appear hazy. However, as fuels cool, dissolved water becomes visible as haze. Conversely, as fuels are heated, water haze disappears. 

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