Equipment for production of nitroglycerine

Diagram of Nobel nitrator made of lead (Nobel, U.S. Pat. 57175 (1866), after Nauckhoff and Bergstrom [7]). 

Cast iron nitrators (Fig. 16) were used [6] more often than lead ones for nitrating nitroglycerine in the U.S.A. 

nitroglycerine nitrator with two mechanical stirrers (ca. 1 ton of nitroglycerine produced in one batch Symmes [6]). 

In the recently introduced continuous methods of nitroglycerine manufacture nitrators made from acid resistant steel are used since the art of welding stainless steel had progressed remarkably by the 1930 s. The design and construction of nitrators for nitrating glycerine are included in the descriptions of individual methods of nitration. 

If compressed air stirring is used, attention should be paid to the purity of air. Usually the air coming from the compressor contains a certain amount of lubricating oil. If this oil were to enter the nitrator it would react with the mixed acid and produce a dangerous rise in temperature. Thus the air must be purified before entering the nitrator. Generally a filter filled with coke or pumice is used. 

Between the filter and the nitrator a reservoir of compressed air, fitted with a safety valve set for 4 atm pressure, should be installed. In the event of any breakdown in the compressor and any pause in the in-flow of compressed air, a steel cylinder filled with compressed nitrogen (or carbon dioxide) kept ready for this emergency should be used to supply gas to the stirrer pipe. While stirring is interrupted the supply of glycerine to the nitrator must be stopped. 

Stirring by means of compressed air has a drawback, in that a certain quantity of nitric add which is volatile is carried out of the nitrator and thus by decreasing the nitric add content in the nitrator, can contribute to a diminished yield of the whole process. Experience has indeed shown that with mechanical stirring the output is usually higher by about 2% as compared with compressed air stirring. 

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Technological principles of nitroglycerine manufacture Mixed acid composition and yield of the process Equipment for production of nitroglycerine Stirring... 

One of the other objectives is intensification — the reduction of hazards by major reductions in the size of equipment for processes which retain the same chemical route. The classic example is the production of nitroglycerine ... 

Safety. Because of the relatively small size of continuous-process equipment, there is less material in process at any time than at certain times in a comparable batch process. For example, at the completion of a batch-process nitration and during its normal separation of the product from spent nitrating acid, the entire batch of an often hazardous compound will be present in the equipment. In the continuous process, only as much material need be present in hazardous conditions as needed to gain sufficient reaction or process time. In the case of high explosives made by nitration, such as nitroglycerine, this inherent safety factor of a continuous process is very attractive. 

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