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Carbon dioxide solubilization

The operating conditions for the extraction column were selected from the experimental data previously measured by choosing the conditions that yield the more favorable capacity and selectivity of carbon dioxide for the FFA fraction. We selected a pressure of 21 MPa and a temperature of 323K. A flowsheet of the proposed extraction process is shown in Figure 1. The separation of the oil components from the solvent stream exiting the extraction column is made in two steps, named SCi and SCm, in order to regenerate the most part of the solvent. The raffinate stream, S2, flows to a third separation column, SCD, to regenerate the carbon dioxide solubilized in that stream. [Pg.488]

One ion-exchange process, which was used for several years by Quebec Lithium Corp., is based on the reaction of P-spodumene with an aqueous sodium carbonate solution in an autoclave at 190—250°C (21). A slurry of lithium carbonate and ore residue results, and is cooled and treated with carbon dioxide to solubilize the lithium carbonate as the bicarbonate. The ore residue is separated by filtration. The filtrate is heated to drive off carbon dioxide resulting in the precipitation of the normal carbonate. [Pg.222]

Because carbon dioxide is about 1.5 times as dense as air and 2.8 times as dense as methane, it tends to move toward the bottom of the landfill. As a result, the concentration of carbon dioxide in the lower portions of landfill may be high for years. Ultimately, because of its density, carbon dioxide will also move downward through the underlying formation until it reaches the groundwater. Because carbon dioxide is readily soluble in water, it usually lowers the pH, which in turn can increase the hardness and mineral content of the groundwater through the solubilization of calcium and magnesium carbonates. [Pg.2255]

Slurry-phase bioremediation is typically more rapid than other types of bioremediation since contaminants are solubilized in a slnrry, making them more readily available to microorganisms. The process is enhanced by providing the microorganisms with appropriate nutrients and environmental conditions to optimize the reaction rate. Bioremediation can degrade organic compounds to carbon dioxide, water, and other prodncts leaving little or no residual waste from the treatment process. [Pg.721]

As its name suggests, supercritical fluid extraction (SEE) relies on the solubilizing properties of supercritical fluids. The lower viscosities and higher diffusion rates of supercritical fluids, when compared with those of liquids, make them ideal for the extraction of diffusion-controlled matrices, such as plant tissues. Advantages of the method are lower solvent consumption, controllable selectivity, and less thermal or chemical degradation than methods such as Soxhlet extraction. Numerous applications in the extraction of natural products have been reported, with supercritical carbon dioxide being the most widely used extraction solvent. However, to allow for the extraction of polar compounds such as flavonoids, polar solvents (like methanol) have to be added as modifiers. There is consequently a substantial reduction in selectivity. This explains why there are relatively few applications to polyphenols in the literature. Even with pressures of up to 689 bar and 20% modifier (usually methanol) in the extraction fluid, yields of polyphenolic compounds remain low, as shown for marigold Calendula officinalis, Asteraceae) and chamomile Matricaria recutita, Asteraceae). " ... [Pg.3]

In order to remove the undesirable Texanol, ve extracted the pigment with supercritical carbon dioxide which was held at a low pressure (100 atm) for five minutes. The extract was found to contain Texanol. We increased the carbon dioxide pressure to 400 atm for five minutes to extract the pigment additive. The pressure control in SFE allows us to control the solubilizing power of the carbon dioxide, therefore, perform selective extractions. [Pg.305]

The environmentally benign, nontoxic, and nonflammable fluids water and carbon dioxide (C02) are the two most abundant and inexpensive solvents on Earth. Water-in-C02 (w/c) or C02-in-water (c/w) dispersions in the form of microemulsions and emulsions offer new possibilities in waste minimization for the replacement of organic solvents in separations, reactions, and materials formation processes. Whereas the solvent strength of C02 is limited, these dispersions have the ability to function as a universal solvent medium by solubilizing high concentrations of polar, ionic, and nonpolar molecules within their dispersed and continuous phases. These emulsions may be phase-separated easily for product recovery (unlike the case for conventional emulsions) simply by depressurization. [Pg.135]

The problem in choosing a polar SF for solubilizing polar solutes is that both the boiling point and the critical point are elevated by the polarity since supercritical operation requires T>TC, high temperatures are mandated in such cases. Thus for ammonia, the critical temperature, Tc = 132°C, must be exceeded for practical operation. A widely used compromise between polar substances with high values of Tc and nonpolar substances with low values of 5liq is carbon dioxide, for which Tc = 31°C and 5Uq = 8.9. Other factors involved in choosing an SF phase are elaborated by Schoen-makers et al. [191. [Pg.30]


See other pages where Carbon dioxide solubilization is mentioned: [Pg.211]    [Pg.211]    [Pg.119]    [Pg.233]    [Pg.209]    [Pg.211]    [Pg.211]    [Pg.119]    [Pg.233]    [Pg.209]    [Pg.2575]    [Pg.359]    [Pg.306]    [Pg.817]    [Pg.825]    [Pg.1010]    [Pg.227]    [Pg.151]    [Pg.361]    [Pg.612]    [Pg.846]    [Pg.270]    [Pg.12]    [Pg.13]    [Pg.292]    [Pg.292]    [Pg.305]    [Pg.339]    [Pg.339]    [Pg.618]    [Pg.619]    [Pg.132]    [Pg.141]    [Pg.151]    [Pg.399]    [Pg.13]    [Pg.1416]    [Pg.11]    [Pg.145]    [Pg.276]    [Pg.143]    [Pg.79]    [Pg.280]    [Pg.315]    [Pg.76]    [Pg.271]   
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