Multistage countercurrent system

The acidic contaminants can also be removed by employing a system that utilizes extractions, precipitation, distillation, and other treatments for rendering the waste stream acceptable for current disposal standards (18—20). First Chemical Corporation uses such a system. Residual nitric acid can be removed by a multistage countercurrent Hquid-Hquid extraction. The nitric acid (ca 25%) is then reconcentrated by distillation for further use. 

A countercurrent multistage extraction system is shown below, which is to be modelled as a cascade of equilibrium stages. 

Y for extract or solvent fed into a multistage countercurrent extraction system (kg/m3)... 

Nutrient Rerxn/eryFrom Gas Streams- A multistage scrubbing system captures fumes from the reactors and any dust that escapes the cyclones. The nutrient content of the scrubber liquor increases as it moves countercurrently throi Qh the reactor gas scrubbing system to the granulator exhaust gas scrubber. Nutrient salts in scrubber liquor are recycled to the reactors. There are no liquid effluents from the plant. 

One of the most complicated systems for mass balance calculations is a multistage countercurrent washing system. Figure 16.27 shows an example of a nine-stage system, with an additional separator on the system overflow as is used to minimize product losses in washing of wheat starch. The most suitable separator in this specific application is a 10 mm hydrocyclone operated at a... 

These multistage, countercurrent towers are very effective, both with respect to liquid-handling capacity and extraction efficiency, particularly for systems of low interfacial tension which do not require m hanical agitation for good dispersion. Their mass-transfer effectiveness results because (I) axial mixing of... 

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