Nitroglycerine continuous methods

From experience gained over many years, special equipment and methods of nitration and purification of nitroglycerine have been developed and certain traditions established. Recently, however, changes have occurred in this field. Continuous methods of nitroglycerine manufacture have been introduced. In many cases they have revolutionized traditional techniques and led to new manufacturing processes. 

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. 

All this makes the manufacture of nitroglycerine particularly dangerous and all that has been said previously with regard to the danger of TNT manufacture and the advisability of producing it by continuous methods applies with much greater emphasis to nitroglycerine. 

The continuous method of nitroglycerine manufacture invented by A. Schmid [38] involves not only continuous nitration, but also continuous separation and washing of the product. A novel idea introduced by Schmid was the nitrator made of acid-resistant steel with mechanical stirring (Fig. 38). 

Fig. 46. Flow-sheet of continuous method of manufacture of nitroglycerine according...

Fig 2 Flow-Sheet of Continuous Method of Manufacture of Nitroglycerine According to Raczynski... 

Nitroglycerin. NG was manufd in Switzerland by the continuous methods of Schmid-Meissner and of Biazzi, which were preferred to batch processes (See Vol 3, C501-L ff)... 

Continuous methods of nitroglycerine manufacture Schmid process Washing nitroglycerine Schmid-Meissner process Raezyhski process Biazzi process... 

Flow-Sheet of Continuous Method of Manufacture of Nitroglycerin. 

The prime Ordn use for sulfuric acid is in the mixed nitiic-sulfiiric acid used in the mixed add nitration of raw materials to form expls and proplnts. The techniques and procedures are presented in Vol 2, ClOl-R to C103-L under Preparation of NC s in Vol 3, C501-L to C510-L under Continuous Methods for Manufacturing Explosives in Vol 6, G98-R to G103-R. under Glycerol Trinitrate or Nitroglycerin (NG) and in Vol 8, N40-R to N88-R under Nitration ... 

Figure 8-7. Schmid-Meissner continuous method for manufacturing nitroglycerin.

Originally 2% of water were added to the spent acid and this prevented the separation of nitroglycerine at temperatures from 10 to 15°C. Nevertheless in 1906 a tank filled with this dilute spent acid exploded while being transported. Further experiments showed that nitroglycerine can separate from acid diluted in that way if its temperature falls below 10°C. Addition of 5% water was therefore introduced, to prevent separation of nitroglycerine even at a temperature of 0°C. At the present time this procedure is widely used with new methods of nitration including continuous processes. 

A flow-sheet for nitroglycerine manufacture by the continuous Schmid method is shown in Fig. 43. 

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