Hydrocarbons water content

FIGURE 7 Schematic of the dynamic protrusion of surfactant monomers from spherical and rod-shaped micelles into surrounding bulk phase to enhance hydrocarbon-water content. [From Lindman, B., and Wennerstrom, H. (1980). Top. Curr. Chem. 87, 1-83.]... 

An important application of the critical solution temperature is to the determination of the water content in such substances as methyl and ethyl alcohols. Here the system is usually the alcohol and a hydro carbon, such as -hexane or dicyclohexyl the water is, of course, insoluble in the hydrocarbon. Thus, the methyl alcohol - cyclohexane system has a C.S.T. of 45 -5° and even 0 01 per cent, of water produces a rise of 0-15° in the C.S.T. The experimental details are given below. 

Dry gas gas where the water content has been reduced by a dehydration process or gas containing Htde or no hydrocarbons commercially recoverable as hquid product. 

Gaseous and Hquid nitrogen Nitrogen, min % (mol/mol) Oxygen Water, ppm (v/v) Dew point, °C Total hydrocarbon a content... 

Methanol eoncentration has essentially no effect on predicted water content of the liquid-hydrocarbon phase. The water eontent (not shown in the tables) was about 0.02 mol%. 

A correction for acid gas should be made when the gas stream contains more than 5% COs and/or H2S. Figures 8-2 and 8-3 may be used to determine the water content of a gas containing less than 40% total concentration of acid gas. As an example, assume the example gas from the previous paragraph contains 15% H2S. The water content of the hydrocarbon gas is 94.8 Ib/MMscf. From Figure 8-3, the water content of HjS is 400 Ib/MMscf. The effective water content of the stream is equal to (0.85 )(94.8)- (0.]5)(400)or 141 Ib/MMscf. 

Conventional pipeline calculations in which "dry" hydrocarbon flashes are performed to determine the hydrocarbon liquid formation the liquid water condensed is estimated using one of the available natural gas water content charts (1, 15), and the Hammerschmidt equation (11) and a graphical correlation are used to... 

The ability of the SRK equation of state to reliably predict the vapor phase water content of natural and synthetic gas systems has been demonstrated. In addition, the ability of the PFGC-MES equation to describe the phase behavior of hydrocarbon, acid gas, methanol, water systems has been described. Both... 

Figure 1 shows a reversed micelle where the bulk solvent is a hydrocarbon and the core is a water pool surrounded by surfactant. These systems possess unique features as the physical properties of the water pools only start to approach those of bulk water at high water content when the pool radii are >150 pools with radii as small as 15 can be constructed (1, 25). These systems have been used to investigate the nature of several inorganic reactions by stopped flow methods (26, 27). They have also been used to produce so-called naked ions, i.e., ions that possess a minimum of aqueous solvation (28). The system strongly promotes many reactions, a fact attributed to the unusual nature of the water in this system. 

The relationship of the selectivity towards rc-electrons can be understood from the differences in the retention factors of polycyclic aromatic hydrocarbons (Figure 3.13). The difference in the retention factors on end-capped and non-endcapped stationary phase materials is less than that of alkylbenzenes. This is due to the water content of the stationary phase. The content may be higher in non-endcapped bonded phases. 

In that case the self diffusion coefficient - concentration curve shows a behaviour distinctly different from the cosurfactant microemulsions. has a quite low value throughout the extension of the isotropic solution phase up to the highest water content. This implies that a model with closed droplets surrounded by surfactant emions in a hydrocarbon medium gives an adequate description of these solutions, found to be significantly higher them D, the conclusion that a non-negligible eimount of water must exist between the emulsion droplets. 

In the subsurface, kerosene volatilization is controlled by the physical and chemical properties of the solid phase and by the water content. Porosity is a major factor in defining the volatilization process. Galin et al. (1990) reported an experiment where neat kerosene at the saturation retention value was recovered from coarse, medium, and fine sands after 1, 5, and 14 days of incubation. The porosity of the sands decreased from coarse to fine. Figure 8.9 presents gas chromatographs obtained after kerosene volatilization. Note the loss of the more volatile hydrocarbons by evaporation in all sands 14 days after application and the lack of resemblance to the original kerosene. It is clear that the pore size of the sands affected the chemical composition of the remaining kerosene. For example, the fractions disap-... 

There have been a number of reports of the use of enzymes in the extraction of oils from sources such as fish, rape seed, yeast, palms, and soya beans. Celluloses and pectinases are used in pdm oil extraction. In soya bean and fish, much oil has been found to be associated with protein, so that addition of proteases increases the yield of oil and protein. Use of thermostable proteases is preferred, but m general the use of enzymes is limited by the minimal water contents of the various process streams. Trichoderma uride and A niger celluloses, hemicellulases and proteases have been used to extract hydrocarbons from Euphorbia plants 39 40) and similar enzymes used to extract sapogenins from Helleborus 41). 

The effect of the moisture level in the eluent on the retention behavior is most pronounced with the least polar solvents, such as the hydrocarbons, in which water has a very limited solubility, usually less than 100 ppm. Conversely, the greater the solubility of water in the organic solvent is, the smaller the effect. For example, the water content of methylene chloride may vary by several parts per million without appreciably changing the k values as the solubility of water in CHtCIt is about 0.2%. 

Ordinarily water content may be determined by a Karl Fischer titration, but for the low concentrations in aliphatic hydrocarbons this method is filled with difficulties. To obtain even modest accuracy such as 5 ppm at HtO levels about or below 30 ppm as specified by the German Standard DIN S1777 relatively large eluent volumes (>2001 ) are required. On the other hand, the absolute and relative retentions are sensitive to 1 to 2 ppm of water consequently, two different batches of eluent with identical water content according to the above mentioned Karl Fischer titration can yield different retention values. Therefore, it is impossible to use titration as the sole method for eluent standardization. The reproducibility of adsorption chromatography, however, can be increased by continuously recycling a sufficiently lapge volume in a closed system to maintain equilibrium. 

Figure 8 shows a separation of condensed aromatic hydrocarbons in which the water content of n-heptane used as the eluent was controlled by MCS. The water concentrations as determined by Karl-Fischer titration are also included for comparison. If all variables such as the water content of the silica in the MCS, the temperature of both MCS, and the chromatographic column are kept constant, the reproducibility of the k values is 2.5%. 

Soil type and heterogeneity of the soil influence well locations and well screen intervals. As the percentage of fine grains in the soil increases, permeability decreases and water content increases. In fine-grained soils, the effective radius of treatment of DVE is reduced, meaning there is a smaller area where the vacuum is sufficient to induce in situ volatilization of hydrocarbons. 

McDow, S. R., M. Vartiainen, Q. Sun, Y. Hong, Y. Yao, and R. M. Kamens, Combustion Aerosol Water Content and Its Effect on Polycyclic Aromatic Hydrocarbon Reactivity, Atmos. Environ., 29, 791-797 (1995). 

The influence of the addition of cetyl trimethyl ammonium chloride, CTAC, to the reverse micellar solution affects the droplet size and micellar interactions, as demonstrated by the DQLS experiment (64). Addition of CTAC to micellar system at a given water content leaves the droplet size unchanged, whereas a decrease in the intermicellar attraction has been observed. This decrease is more important for high CTAC concentrations. This has been interpreted to steric repulsion induced by the long hydrocarbon tail of CTAC (C ft). Thus, the addition of this compound to CdS synthesis could modify the nucleation and/or growth process. The experiments were performed by solulization of CTAC in the micellar solution containing either sodium sulfide or Cd(AOT)2. 

In contrast to its MIR counterpart, an important application of NIRS is the routine quantitative determination of species, such as water, proteins, hydrocarbons, and fats, for example, in food or feed products, but also in the petroleum and chemical industries. Figure 13 illustrates a collection of spectra from a pharmaceutical product with varying water content. It shows that a quantitative application can be... 

The correlation on which these figures are based is good to within five percent. This is about as accurate as water content can be measured. The correlation was developed for dry gases. The presence of heavier hydrocarbons in wet gases and retrograde gases increases the water content by as much as 10 percent at 1000 psia and 20 percent at 10,000 psia. 

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