Regenerators heat extraction

The process should be able to handle various types of feedstocks by the inclusion of appropriate heat extraction facilites as dictated by the heat balance between the reactor and the regenerator. 

While solvent volatility at ambient conditions has little effect on liquid-liquid equilibria [because the pure component vapor pressure cancels out in Equation (10.9)], solvent volatility nonetheless can be important in solvent regeneration, particnlarly if simple or extractive distillation is used to recycle solvent. These techniqnes are commonly nsed in solvent regeneration when extraction is applied to the recovery of many organic chemicals (e.g., acetic acid [34] recovery, which typically involves extractive distillation to regenerate the solvent and prodnce glacial acetic acid). Then the latent heat of vaporization is also an important consideration. Usnally, however, it is desirable to have regeneration withont solvent distillation, as that approach is often inefficient and expensive. 

The common methods of purification, discussed below, comprise distillation (including fractional distillation, distillation under reduced pressure, sublimation and steam distillation), crystallisation, extraction, chromatographic and other methods. In some cases, volatile and other impurities can be removed simply by heating. Impurities can also sometimes be eliminated by tbe formation of derivatives from which the purified material is regenerated (see Chapter 2). 

Used alumina can be regenerated by repeated extraction, first with boiling methanol, then with boiling water, followed by drying and heating. The degree of activity of the material can be expressed conveniently in terms of the scale due to Brockmann and Schodder (Chem Ber B 74 73 1941). 

The acid extract phase is separated, diluted with water, and heated to regenerate isobutylene. The isobutylene is then caustic and water washed to remove traces of acid, distillation dried, and rerun. The unreacted C4 stream, containing normal butenes, is also caustic washed before further processing. 

When substances adsorbed on aerosol particles are to be determined, the gas is passed through a membrane or other filter and the filter is dissolved in or extracted with a suitable solution. An interesting method is used for determination of fluoride adsorbed on atmospheric aerosols [87]. The particles are trapped on a filter impregnated with citric acid and heated to 80 °C, while the fluorides pass through and are absorbed in a thin layer of sodium carbonate in a spiral absorber. The sodium carbonate is periodically washed with a sodium citrate solution, in which solution the fluoride is then determined, and the absorption layer regenerated. 

An essential step in industrial solvent extraction is the regeneration of the extractant. This can be done in many ways, e.g., by distillation, evaporation, or stripping (back-extraction). While distillation and evaporation do not discriminate between solutes (the diluent is simply removed by heating), stripping, by careful choice of strip solution and conditions, can be made highly selective. Alternatively, aU the solutes can be stripped and then subjected to a selective extraction by changing the extractant examples of both types of process will be found in Chapter 13. The possibilities are many, and it may be worthwhile to explore new paths. 

Consider a steam power plant operating on the ideal regenerating Rankine cycle 1 kg/sec of steam flow enters the turbine at 15 MPa and 600°C and is condensed in the condenser at lOkPa. Some steam leaves the high-pressure turbine at 1.2 MPa and enters the open feed-water heater. If the steam at the exit of the open feed-water heater is saturated liquid, determine (1) the fraction of steam not extracted from the high-pressure turbine, (2) the rate of heat added to the boiler, (3) the rate of heat removed from the condenser, (4) the turbine power produced by the high-pressure turbine, (5) the turbine power produced by the low-pressure turbine, (6) the power required by the low-pressure pump, (7) the power required by the high-pressure pump, and (8) the thermal cycle efficiency. 

The Macro porous polymer (MPP) system is an ex situ technology designed to remove hydrocarbon pollutants from process water, groundwater, and wastewater. This technology uses a patented, porous polymer containing an immobilized extraction fluid that assimilates the hydrocarbons into the polymer structure. The particles are regenerated with an in situ heating cycle, and the contaminants are recovered for reuse, recycle, or disposal. 

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