Stengel process

Under this term are known devices in the form of rotary drums for prepg various substances in the form of small scales (flakes). Such drums, known as flakers are used in the manuf of TNT. Flaking can also be done by using water-cooled belts, such as in the Stengel process for making flaked Ammonium Nitrate. This process is briefly described in this Encycl, Vol 1, p A315-R. 

J.J. Minnick, USP 3447982(1969) CA 71, 51827y(1969) [A blasting agent is described which contained AN made by Stengel Process (See Vol 1 of Encycl, p A315-R)-... 

FLOW DIAGRAM FOR THE PRODUCTION OF AMMONIUM NITRATE BY THE STENGEL PROCESS (COMMERCIAL SOLVENTS)... 

STENGEL PROCESS. A method of making ammonium nitrate fertilizer from anhydrous ammonia and nitric acid. The fertilizer panicles can be made in different sizes according to use. 

Stengel Process (Refs 99, 105, 114 118). The neutralization of ammonia with preheated nitric acid takes place in a packed, tubular reactor at about 204°. The molten AN... 

Besides the above Stengel Process, there are two other modern commercially important processes — the Prilling Process and the Crystallization Process (See inclosed flowsheets)... 

In the United States the Stengel process is used to produce anhydrous ammonium nitrate directly. In this process ammonia and 58% nitric acid are preheated with fresh steam and fed into a packed vertical tube reactor at 3.5 bar and 240°C. The mixture of NH4NO3 and steam is expanded into a vacuum in a centrifugal separator. After stripping with hot air, a 99.8% NH4NO3 melt is discharged onto a cooled steal belt, solidified and then broken up or granulated295. 

FIGURE 11.9 Ammonium nitrate by the Stengel process. Intermediate evaporation before prilling or granulation would be employed for the production of a high-density product. 

The Stengel process uses sufficiently high preheat temperatures for ammonia gas and a nitric acid solution such that complete evaporation of the residual water occurs when the heat of reaction is added to this [16]. 

In the Stengel process ammonia gas preheated to 145°C is blended with about 60% nitric acid preheated to 165° C under pressure in a packed stainless steel reactor (Fig. 11.9). This has now become a routine procedure, yet the mixing of a hot strong oxidant with a hot oxidizable material is a process that is fundamentally unnerving to a chemist. Doing this provides sufficient additional heat from the neutralization reaction to nearly completely evaporate the residual water [60] (Eq. 11.54). 

Figure 3.9 A schematic of the Stengel process for making ammonium nitrate solution. Source. [5],...

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