Sparger ammonia

Fig. 17. Pilot-plant ammoniator—granulator, (a) Side view, showiag placement of acid and ammonia spargers, and (b) feed end view (71,72).

Fig. 19. TVA-type ammoniator—granulator incorporating a pipe cross reactor. 1, ammonia sparger, located at the 4 o clock position 11.4 cm from granulation shell with holes facing the rotating stream 2, phosphoric acid sparger, located to discharge phosphoric acid onto the top and near the center of the rotating bed of materials 3, pipe cross reactor 4, scmbber Hquor distributor, located above the bed in granulator to dribble scmbber Hquor onto bed.

The ammonia sparger design provides a smooth reaction and good mixing of the reactants. 

During the course of the many laboratory-scale experiments conducted, it was found that the addition of surface agents (i.e., anionic, cationic and nonionic) did not improve the crystalline habit of the resultant product. An attempt to use an air sparger to simultaneously agitate the mother liquor and speed evaporation of the ammonia resulted in a rapid clogging of the sparger by precipitated silver azide. 

One of the earliest drum mixers that was applied in the fertilizer industry for agglomeration (granulation) produced a curtain of solid materials as sketched in Fig. 7.24. If acid and ammonia are sprayed onto the curtain and/or added by sparger tubes granulation occurs during ammoniation. The co-processing (ammoniation and granulation) makes this technique a most beneficial one. 

In the direct neutralization process, ammonia is distributed using a perforated pipe (sparger) positioned beneath the bed of material in the granulator. If sulfuric acid is used, it too is usually distributed through a sparger beneath the bed of material whereas the phosphoric acid, if used, is most often sprayed or dribbled on top of the bed of material. When sulfuric acid is used, precautions should be taken to ensure that the acid is added at a particular location with respect to the ammonia to ensure quick and uniform neutralization and thus minimize the unwanted reaction of sulfuric acid with muriate of potash (MOP) that is usually present in most NPK formulations. This acid/MOP reaction causes the formation of very corrosive hydrochloric acid, which reacts rapidly with ammonia to form a dense fume of ammonium chloride that is very difficult and costly to collect in the plant s emission control (scrubbing) system. 

In the process, air is introduced uniformly into the bottom of the reactor via a distributor plate. The propylene and ammonia are introduced into the fluidized bed above the distributor plate via a separate sparger. The design of these gas distribution systems has evolved over the years improving the reactor yield (Ohta and Yokura, 1996.)... 

Two copper-solvent approaches were tested 10% ammonia with an air sparger or EDTA/ammonia/ethylenediamine/H202. The latter system produced much less corrosion to exposed steel than the ammonia/air mixture, while being able to remove large amounts of copper. The solvent system finally chosen was h) copper stage ... 

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