Separation, pressure reduction

The fluid discharged from the SCWO reactor passes through a cooler and enters a phase-separation vessel. Gases and liquids then flow to separate pressure-reduction stations before entering a low-pressure phase-separation vessel. Noncondensable gases, mostly carbon dioxide, are monitored and filtered before release to the environment via the plant HVAC system. Liquids are monitored and transferred to the brine recovery area, which is identical to the one used in the baseline incineration system. If fluid does uot meet release specifications, it is returned to a storage tank for off-specification product and reprocessed in the SCWO reactors. 

The vapor pressure of a crude oil at the wellhead can reach 20 bar. If it were necessary to store and transport it under these conditions, heavy walled equipment would be required. For that, the pressure is reduced (< 1 bar) by separating the high vapor pressure components using a series of pressure reductions (from one to four flash stages) in equipment called separators , which are in fact simple vessels that allow the separation of the two liquid and vapor phases formed downstream of the pressure reduction point. The different components distribute themselves in the two phases in accordance with equilibrium relationships. 

Gas is sometimes produced at very high pressures which have to be reduced for efficient processing and to reduce the weight and cost of the process facilities. The first pressure reduction is normally made across a choke before the well fluid enters the primary oil / gas separator. 

Closely related to the use of rhodium catalysts for the hydrogenation of phenols is their use in the reduction of anilines. The procedure gives details for the preparation of the catalyst and its use to carry out the low-pressure reduction of /j-aminobenzoic acid. Then, as in the preceding experiment, advantage is taken of the formation of a cyclic product to carry out the separation of a mixture of cis and trans cyclohexyl isomers. 

Multiple Separators for More EfOcient Separation of Cholesterol from Beef Tallow. Since the solvent power of CO2 depends upon its density, a step-wise reduction of separation pressure will alter the CO2 density so that the soluble components of beef tallow can be separated and collected in different fractions. 

Fractionation of silicone and fluoro fluids. Since solubility depends on molecular weight and temperature/pressure it is possible, particularly with products such as silicone oils and fluorinated liquids" to separate fractions by solubilization and then pressure-reduction steps. 

Most applications use a combination of pressure- and temperature change. After pressure-reduction the extraction gas is heated so that it reaches the gaseous state. In this phase, no solvent-power of the extraction gas is present for any substances and therefore complete separation of extracted substances takes place. In cycling the extraction gas after separation, it has to be condensed, under-cooled to prevent cavitation of the pump, and recompressed and heated up to extraction temperature. 

Heatless adsorption is a cyclical process for the purification of gaseous mixtures by the separation of the gas into two streams. One stream which contains more of the more strongly adsorbable materials is called the purge. The other process stream is called the product stream and contains less of the more-adsorbable components. Pressure reduction during the purging cycle coupled with the use of product purge gas and short cycles allows the process to operate without the use of heat for bed... 

Processes involving total-pressure reduction to remove the adsorbed species, called pressure-swing adsorption (PSA) or heatless adsorption, are mechanically complex, since they must include separate adsorption, depressurization, desorption, and repressurization steps. To accommodate a steady flow of feed and products, several beds - usually three or more in parallel -are used. A typical four-bed process flowsheet is shown in... 

The amounts of hydrogen and oil were controlled according to known principles [12], Propane, hydrogen and oil were mixed at room temperature (see M). The mixture was heated to the desired reaction temperature and brought into an HPLC tube filled with a catalyst powder (see Temp and reactor). After the reactor samples were collected from the high pressure section using an HPLC valve (see A and [13]). The pressure was reduced to atmospheric pressure (see P), and the oil and the gases were separated (see Sep). Finally, the gas flow was measured (see F). This flow, mainly propane, was controlled by a pressure-reduction valve (see P). 

Supercritical fluid extraction (SFE) is a suitable process for many separation problems. The regeneration of the supercritical fluid is as important as the extraction step itself Therefore this paper presents a method to do this in a more isobaric way than the customary pressure reduction regeneration. For the example of soil remediation we have investigated the activated carbon regeneration of supercritical carbon dioxide loaded with the low-volatile polycyclic aromatic hydrocarbon (PAH) pyrene. Characteristics of supercritical fluid extraction for soil remediation are elevated temperatures and pressures up to 370 K and 300 bar. For this reason adsorption isotherms of pyrene on activated carbon up to these conditions are measured first. Subsequently this method is used to regenerate carbon dioxide in a closed solvent cycle plant with a 4 1 extractor. An economic analysis using these results indicate that the soil remediation costs will decrease for about 20 - 30 % by means of an activated carbon adsorber. 

A great advantage of supercritical fluids is the possibility to separate the extracted solute from the solvent by simple pressure reduction to subcritical pressures. The solubility of most solutes in supercritical fluids virtually vanishes and therefore the solutes precipitate at these conditions. For example, pyrene solubil-... 

---