Stirred-tank neutraliser

The neutralisation takes place in a stirred tank reactor with cooling coils to which the sulphonic acid (ex cascade sulphonation reactor train or from storage) and the diluted caustic are continuously added. The stirred-tank neutraliser is the final reactor in the total train of seven (4 sulphonation reactors, 1 ageing vessel, 1 hydrolyser reactor and last, but not least, the neutralisation reactor). 

Make a sketch of the cascade of the 4 reactors with gravity overflow from one to the next, leaving room and height for the ageing tank and stabilising reactor (see 5.5.10.) and a final stirred-tank neutraliser reactor. 

Reiter, M., Buchacher, A., Bltlml, G., Zach, N., Steinfellner, W., Schmatz, C., Gaida, T., Assadian, A., and Katinger, H., Production of the HIV-1 Neutralising Human Monoclonal Antibody 2F5 Stirred Tank Versus Fluidized Bed Culture, Animal Cell Technology, (R. E. Spier, J. B. Griffith, and W. Berthold, eds.), p. 333, Butterworth-Heinemann, Oxford (1994)... 

It should be pointed out that a jet-type tubular turbulent reactor of similar design, instead of stirred tank reactors with mechanical stirrers, can and should be used at other stages of the process of chlorinated BR production, in particular, for the neutralisation of the modified polymer solution (the rate constant of the interaction between mineral acids and alkalis is k 10 1/mols), removal of salts and other substances from the chlorinated BR solution by water washing (extraction), removal of back solvent (extraction), and introduction of the stabiliser-antioxidant and adhesion reducing powder (mixing) into the polymer solution. 

Ballestra Sulphurex plants normally include an ageing vessel and a hydrator reactor (both of which are agitated and contain cooling water coils see 5.5.10.) as part of the total stirred tank reactor train. Normally a stirred tank reactor for neutralisation is installed as the last stirred tank reactor in the total reactor train. 

However, because both acids and bases are used in cleaning, it may be possible to store these chemicals in a stirred buffer tank to allow the solution to neutralise. This solution may then may be slowly added to the concentrate waste to dilute it and allow for a safe disposal (Mauguin and Corsin 2005). Note that the volume of this discharge is much lower than both the concentrate and filter backwash discharges. 

The liquor is examined now and then to see whether it is alkaline, neutral, or acid. As soon as it has become slightly acid, it is run from the apparatus into a large settling-tank, where it generally becomes neutralised by a certain quantity of undecomposed oxysulphide of calcium held in it. If, after stirring for some time, the liquor preserves its acid reaction, sulphide of calcium is added until complete neutralisation is effected, which is ordinarily made apparent by a black precipitate of sulphide of iron. 

---