Extraction battery

Algebraic Comptttation This method starts with calculation of the quantities and compositions of all the terminal streams, using a convenient quantity of one of the streams as the basis of calculation. Material balance and stream compositions are then computed for a terminal ideal stage at either end of an extraction battery (i.e., at Point A or Point B in Fig. 18-81), using equilibrium and solution-retention data. Calculations are repeated for each successive ideal stage from one end of the system to the other until an ideal stage which corresponds to the desired conditions is obtained. Any solid-hquid extraction problem can be solved by this method. 

An enamel-lined rotary digester, which was heated by direct steam, was used for the hydrolysis in these investigations. The sugars produced by the hydrolysis were extracted from chips in an extraction battery. The sugar solution was neutralized with lime, filtered and then prepared for fermentation. 

Figure 14.3. Representation of countercurrent extraction batteries, (a) A battery of mixers and settlers (or separators), (b) Schematic of a three-stage countercurrent battery, (c) Simulation of the performance of a three-stage continuous countercurrent extraction battery with a series of batch extractions in separatory funnels which are designated by circles on the sketch. The numbers in the circles are those of the stages. Constant amounts of feed F and solvent S are mixed at the indicated points. As the number of operations is increased horizontally, the terminal compositions Et and R3 approach asymptotically the values obtained in continuous countercurrent extraction (Treybal, 1963, p. 360).

When K is not truly constant, some kind of mean value may be applicable, for instance, a geometric mean, or the performance of the extraction battery may be calculated stage by stage with a different value of K for each. The material balance around the first stage where the raffinate leaves and the feed enters and an intermediate stage k (as in Fig. 14.8, for instance) is... 

Trial Estimates and Converged Flow Rates and Compositions in All Stages id an Extraction Battery Cor a Emu-Component Mixture... 

Figure 14.10. Algorithm for computing flows and compositions in an extraction battery of a specified number of stages (after Henley and Seader, 1981).

Co-extraction of Np and Pu The waste from the uranium extraction battery is adjusted to 5 M LiNO and then passed through an IRA-400 column at a high flow rate (30 L/h). The americium is not sorbed. Neptunium and plutonium are stripped by a dilute nitric acid solution and precipitated as a hydroxide, and calcined to yield mixture of oxides. 

It was necessary, because of economic restraints, to locate the americium extraction battery in the same canyon as the mainline PRF TBP extraction equipment. Compromises in americium extraction equipment design and hydraulics were mandated to accommodate the americium extraction system in this existing facility. In particular, all the columns had to be shortened from the optimum heights recommended by the pilot plant studies. The hydraulics of the installed system were such that the organic flowrate to the extraction column (WE-1 Column) was inadequate with the result that the extraction factor was too low to permit quantitative extraction of all the 21tlAm. Furthermore, the combination of a short extraction column and a 1-inch air pulse leg sometimes led to a hydraulic upset whereby the entire column contents were lost recovery from such hydraulic upsets required an hour or more. 

Trial Estimates and Converged Flow Rates and Compositions in aU Stages of an Extraction Battery for a Four-Component Mixture 476 Sizing of Spray, Packed, or Sieve Tray Towers 486 Design of a Rotating Disk Contactor 488 Application of Ion Exchange Selectivity Data 503... 

Schwartzberg, H.G., Torres, A., and Zaman, S. 1982. Mass Transfer in Solid-Liquid Extraction Batteries, Food Process Engineering AIChE Symposium Series No. 218, Vol. 78, pp. 90-101. 

In contrast to the previously described modes of operation, solvent and feed move continuously towards each other in absolute countercurrent extraction. These extractors, e.g. the screw-conveyor extractor, the Bonotto extractor, the Kennedy extractor and extraction batteries with decanter, all move the solid material and are, therefore, mechanically stress objected. For the miscella this requires extended filtration for removing solids. 

In the extraction battery with decanter, several decanters are arranged in succession and the solvent moves countercurrently to the feed. 

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