Viscosity, critical oils, liquids

Batch Stirred Tank SO Sulfonation Processes. If the color of the derived sulfonate is not critical, such as ia the productioa of oil-soluble ag-emulsifiers, a simple batch sulfoaatioa procedure can be employed based on vaporizing liquid SO (Niaol Labs, 1952) (13,263). Pilot Chemical Company adapted the original Morrisroe 60—70% oleum—SO2 solvent sulfonation process (256) to utilize 92% Hquid SO —8% Hquid SO2 mixtures, and more recently usiag 100% Hquid SO. This cold sulfoaatioa low viscosity sulfoaatioa process produces exceUeat quaHty products, and reportedly has also been adapted for continuous processiag as weU. The derived sulfonic acid must be stripped of SO2 solvent after completing sulfonation and digestion. 

Whenever possible, streamline conditions of flow are avoided in heat exchangers because of the very low heat transfer coefficients which are obtained. With very viscous liquids, however, turbulent conditions can be produced only if a very high pressure drop across the plant is permissible. In the processing industries, streamline flow in heat exchangers is most commonly experienced with heavy oils and brines at low temperatures. Since the viscosity of these materials is critically dependent on temperature, the equations would not be expected to apply with a high degree of accuracy. 

The recovery of petroleum from sandstone and the release of kerogen from oil shale and tar sands both depend strongly on the microstmcture and surface properties of these porous media. The interfacial properties of complex liquid agents—mixtures of polymers and surfactants—are critical to viscosity control in tertiary oil recovery and to the comminution of minerals and coal. The corrosion and wear of mechanical parts are influenced by the composition and stmcture of metal surfaces, as well as by the interaction of lubricants with these surfaces. Microstmcture and surface properties are vitally important to both the performance of electrodes in electrochemical processes and the effectiveness of catalysts. Advances in synthetic chemistry are opening the door to the design of zeolites and layered compounds with tightly specified properties to provide the desired catalytic activity and separation selectivity. 

When the polar additive nonylic acid was added into hexade-cane liquid, the contact ratio becomes much smaller than that of pure hexadecane, which is shown in Fig. 39. For hexa-decane liquid, the critical speed to reach zero contact ratio is 50 mm/s, which is much higher than that of mineral oil 13604 because of its much lower viscosity. Flowever, when nonylic acid was added into the hexadecane liquid, the critical speed decreased from more than 50 mm/s to 38 mm/s. The same phenomenon can be seen in Fig. 39(h) which shows the comparison of oil 13604 and that added with 1.8 %wt. nonylic acid. The addition of polar additive reduces the contact ratio, too, but its effect is not as strong as that in hexadecane liquid because the oil 13604 has a much larger viscosity. Therefore, it can be concluded that the addition of polar additives will reduce the contact ratio because the polar additives are easy to form a thick boundary layer, which can separate asperities of the two rubbing surfaces. 

For any pure chemical species, there exists a critical temperature (Tc) and pressure (Pc) immediately below which an equilibrium exists between the liquid and vapor phases (1). Above these critical points a two-phase system coalesces into a single phase referred to as a supercritical fluid. Supercritical fluids have received a great deal of attention in a number of important scientific fields. Interest is primarily a result of the ease with which the chemical potential of a supercritical fluid can be varied simply by adjustment of the system pressure. That is, one can cover an enormous range of, for example, diffusivities, viscosities, and dielectric constants while maintaining simultaneously the inherent chemical structure of the solvent (1-6). As a consequence of their unique solvating character, supercritical fluids have been used extensively for extractions, chromatographic separations, chemical reaction processes, and enhanced oil recovery (2-6). 

Propane or propane/C02 mixtures as liquid, near-critical, or supercritical fluids enhance the solubility of fats and oils (Harrod et al., 2000 Weidner and Richter, 1999). The decrease in viscosity and increase in diffusivity results in a higher hydrogenation rate (Figure 14.4). Harrod et al. (2000) have also demonstrated activity increases by reducing mass-transfer limitations in supercritical propane. 

The physical properties of supercritical fluids tend to lie between those of gases and liquids. The increased density relative to a gas, and the decreased viscosity relative to a liquid, allow supercritical fluids to be used as excellent solvents in many laboratory and industrial applications (19-25). Also, some notable solvation peculiarities of supercritical fluids have been discovered. For example, supercritical water can dissolve nonpolar oils because the dielectric constant of supercritical water decreases drastically near the critical point (26). 

Fig. 1.30 Destruction of the liquid structure of a special oil 57/FS4/1 after passing the critical point on the viscosity curve from [425]. 

A. Buguin and P. Martin were the first to conduct liquid-on-liquid dewet-ting experiments. They deposited PDMS (polydimethylsiloxancs) on the fluorinated oil PFAS (i)olyfluorornethylalkyl.siloxarie), which is an oligomer, the viscosity of which depends on the length of the chain. They measured a critical thickness Cr = 1-3 mm on puddles. This result implies S - —1.8 niN/m and = 3.5 inN/rn. 

While geological sequestration will build generally on the totality of experience with fossil fuel extraction, it will be most directly built on current practice of CO2 injection for enhanced oil recovery (EOR). Conventional extraction methods typically leave substantial oil in place. This oil may be extracted using EOR. Carbon dioxide injection (or flooding in industry jargon) is particularly effective because, as an organic solvent, the CO2 acts to reduce the viscosity of the residual oil and in addition causes the oil to expand thus helping to free it from the porous rock in which it is embedded. Typical EOR floods operate at pressures above the critical point of CO2 so that fluid flow is facilitated by the absence of a liquid-gas interface. 

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