Reversible distillation extractive

However, in general, solvent recovery is an important step in the overall solvent extraction process. Solvent recovery from the raffinate (i.e., water phase) may be accomplished by stripping, distillation, or adsorption. The extract, or solute-laden solvent stream, may also be processed to recover solvent via removal of the solute. The solute removal and solvent recovery step may include reverse solvent extraction, distillation, or some other process. For example, an extraction with caustic extracts phenol from light oil, which was used as the solvent in dephenolizing coke plant wastewaters (4). The caustic changes the affinity of the solute (phenol) for the solvent (light oil) in comparison to water as will be explained in the equilibrium conditions section. Distillation is more common if there are no azeotropes. 

IRMS LC MDGC MS MSA NIF NMR OAV OSV PCA RAS RP SDE SFE SIM SNIF SPME TIC TLC Stable Isotope Ratio Mass Spectrometry Liquid Chromatography MultiDimensional Gas Chromatography Mass Spectrometry Multivariate Sensory Analysis Nasal Impact Frequency Nuclear Magnetic Resonance spectroscopy Odor Activity value Odor Spectrum Value Principal Component Analysis Retronasal Stimulation Reversed Phase Simultaneous steam Distillation Extraction Supercritical Fluid Extraction Selected Ion Monitoring Surface of Nasal Impact Frequency Solid Phase Micro Extraction Total Ion Current Thin Layer Chromatography... 

See also Blood and Plasma. Clinical Analysis Overview Sample Handling. Distillation. Extraction Solvent Extraction Principles. Flow Injection Analysis Industrial Applications. Food and Nutritional Analysis Overview. Geochemistry Soil, Major Inorganic Components. Membrane Techniques Dialysis and Reverse Osmosis. Pharmaceutical Analysis Drug Purity Determination. Water Analysis Freshwater Seawater - Inorganic Compounds Industrial Effluents. 

As far as stationary points of trajectory bundles of distillation at finite reflux lay on trajectories of reversible distillation, these trajectories were also called the lines of stationarity (pinch lines, lines of fixed points) (Serafimov, Timofeev, Balashov, 1973a, 1973b). These lines were used to deal with important applied tasks connected with ordinary and extractive distillation under the condition of finite... 

Diagrams of Extractive Reversible Distillation for Three-Component Mixtures... 

Condition in Tear-Off Points of the Extractive Reversible Distillation Trajectories... 

In both cases, the trajectory tear-off point of sharp reversible distillation in the intermediate extractive section should lie at side 1-3 and the trajectory of intermediate section is a line, which is a geometric locus of points where the straight lines passing through a given point of pseudoproduct are tangent to residue curves. This trajectory reaches side 1-3 at the tear-off point and vertex 2 is the node... 

Nrev of the trajectory bundle at different pseudoproduct points. The location of point and of the whole trajectory of extractive reversible distillation depends on that of the pseudoproduct point x (i.e., on the ratio E/F between the flow rates of the entrainer and the main feeding). Changing the parameter E/F, we get the trajectory bundle of extractive reversible distillation that, for an ideal mixture, fills up the whole concentration triangle. 

We got an important result at reversible distillation in the intermediate section of the column of extractive or autoextractive distillation the component, which is intermediate in the value of phase equilibrium coefficient between the component separated as top product and the component brought in as an entrainer, is exhausted. 

This result also remains valid for azeotropic mixtures. A necessary condition for exhausting of the some component in the intermediate (extractive) section at reversible distillation consists of the fact that the whole trajectory of intermediate (extractive) section should be located in the region where this component is intermediate in phase equilibrium coefficient (in the region of reversible distillation of the intermediate section Reg J. The segment of the side containing only the component separated as top product and component brought in as an entrainer is a boundary element of this region Reg l. ... 

The apphcation of extractive distillation is of great practical importance because it ensures the possibility of sharp separation of some types of azeotropic mixtures into zeotropic products, which is impossible in a colunm with one feeding. The mixture acetone(l)-water(2)-methanol(3) is an example of this type of mixture. Trajectories of reversible distillation of three sections of extractive distillation column, the feeding of which is binary azeotrope acetone-methanol, the extractive... 

Let s examine now the structure of trajectory bundles of sharp reversible distillation for the intermediate (extractive) section of the column with two feedings at separation of different types of azeotropic mixtures, the way we did it for the top and the bottom sections (Fig. 4.21). While composing these diagrams, we used, just as we did before, the data on the phase equilibrium coefficients of present and absent components at the sides of the concentration triangle and the general regularities of the location of the trajectory bundles of sharp reversible distillation. 

It is possible to formulate a general structural condition that should be valid in the tear-off point of the extractive reversible distillation trajectory from a (n - 1)-component face or hyperface of the concentration simplex of any multicomponent azeotropic mixture the phase equilibrium coefficient of the component that is absent in this face or hyperface and does not rank among the top product components and of the entrainer should be smaller than that of the top product components and bigger than that of the entrainer components. 

Kiva, V. N., Timofeev, V. S., Vizhesinghe, A. D. M. C., Chyue Vu Tam (1983). The Separation of Binary Azeotropic Mixtures with a Low-Boiling Entrainer. In The Theses of 5th Distillation Conference in USSR. Severodonezk (Rus.). Knapp, J. R, Doherty, M. F. (1994). Minimum Entrainer Flows for Extractive Distillation A Bifurcation Theoretic Approach. AlChE J., 40,243-68. Koehler, J., Aguirre, R, Blass, E. (1991). Minimum Reflux Calculations for Nonideal Mixtures Using the Reversible Distillation Model. Chem. Eng. Set, 46,3007-21. 

Figure 6.11. About calculation minimum entrainer flow rate E/D)ram- Ki, j and E/D as functions x j (a,b,c, respectively) for extractive distillation of the acetone(l)-water(2)-methanol(3) azeotropic mixture. x[ j = x g concentration of component 1 in tear-off point of intermediate section reversible distillation trajectory on side 1-2 Ki, phase equilibrium coefficient of component i in point j, x), j and E/D, concentration of component 1 in pseudoproduct point and ratio of entrainer and overhead flow rates, respectively, if tear-off point of intermediate section trajectory xj j on side 1-2 coincide with point...

Reversible distillation region of section (Regrev.n Re ev,s Re ev,e) unification of several regions of components order for which one and the same component appears to be (1) the most heavy-volatile for rectifying section, (2) the most light-volatile for stripping section, and (3) middle-volatile between top and en-trainer components for extractive section. 

Extraction of steam distillates by solvents. The apparatus, depicted in Fig. 11,58, 7, may be employed for the continuous extraction of substances which are volatile in steam from their aqueous solutions or suspensions. Solvents of the ether type (i.e., lighter than water) or of the carbon tetrachloride type (i.e., heavier than water) may be used. A reflux condenser is inserted in the Bl9 socket, whilst flasks of suitable capacity are fltted into the lower B24 cone and the upper. B19 cone respectively. For extraction with ether, the flask attached to the upper. B19 cone contains the ether whilst the aqueous solution is placed in the flask fltted to the lower B2i cone the positions of the flasks are reversed... 

Completion of Esterification. Because the esterification of an alcohol and an organic acid involves a reversible equiUbrium, these reactions usually do not go to completion. Conversions approaching 100% can often be achieved by removing one of the products formed, either the ester or the water, provided the esterification reaction is equiUbrium limited and not rate limited. A variety of distillation methods can be appHed to afford ester and water product removal from the esterification reaction (see Distillation). Other methods such as reactive extraction and reverse osmosis can be used to remove the esterification products to maximize the reaction conversion (38). In general, esterifications are divided into three broad classes, depending on the volatility of the esters ... 

With reversible reactions, recycling is warranted when improvement in conversion can be realized by removing some of the product in a separator and returning only unconverted material. In some CSTR operations, the product is removed continuously by extraction or azeotropic distillation. The gasoline addi-... 

Solvent Effects m Extractive Distillation In the distillation of ideal or nonazeotropic mixtures, the component with the lowest pure-component boihng point is always recovered primarily in the distillate, while the highest boiler is recovered primarily in the bottoms. The situation is not as straightforward for an extractive-distillation operation. With some solvents, the component with the lower pure-component boiling point wih be recovered in the distillate as in ordinaiy distillation. For another solvent, the expected order is reversed, and the component with the higher pure-component boiling point wih be... 

The thermodynamic aspect of osmotic pressure is to be sought in the expenditure of work required to separate solvent from solute. The separation may be carried out in other ways than by osmotic processes thus, if we have a solution of ether in benzene, we can separate the ether through a membrane permeable to it, or we may separate it by fractional distillation, or by freezing out benzene, or lastly by extracting the mixture with water. These different processes will involve the expenditure of work in different ways, but, provided the initial and final states are the same in each case, and all the processes are carried out isothermally and reversibly, the quantities of work are equal. This gives a number of relations between the different properties, such as vapour pressure and freezing-point, to which we now turn our attention. 

Reverse-flow reactors Reactive distillation Reactive extraction Reactive crystalization Chromatographic reactors Periodic separating reactors Membrane reactors Reactive extrusion Reactive comminution Fuel cells... 

Acetochlor and its metabolites are extracted from plant and animal materials with aqueous acetonitrile. After filtration and evaporation of the solvent, the extracted residue is hydrolyzed with base, and the hydrolysis products, EMA and HEMA (Figure 1), are steam distilled into dilute acid. The distillate is adjusted to a basic pH, and EMA and HEMA are extracted with dichloromethane. EMA and HEMA are partitioned into aqueous-methanolic HCl solution. Following separation from dichloromethane, additional methanol is added, and HEMA is converted to methylated HEMA (MEMA) over 12 h. The pH of the sample solution is adjusted to the range of the HPLC mobile phase, and EMA and MEMA are separated by reversed phase HPLC and quantitated using electrochemical detection. 

Packed columns are used for distillation, gas absorption, and liquid-liquid extraction only distillation and absorption will be considered in this section. Stripping (desorption) is the reverse of absorption and the same design methods will apply. 

With reversible reactions, sufficient improvement in conversion sometimes can be realized from removing the product to warrant a recycle operation. This can be done by sending the product to a separator and returning only unconverted material. Some systems, moreover, lend themselves to continuous removal of product in equipment integrated with the reactor. Extraction is thus employed in problem P4.06.13 and azeotropic distillation in problems P4.06.14 and P4.06.15. The gasoline additive, methyl-tert-butyl ether, is made in a distillation column where reaction and simultaneous separation take place. 

Reverse osmosis Solvent extraction Ionizing radiation Adsorption Incineration Freezing Distillation Electrolysis Fungal treatment... 

---