Biazzi process

An original version of the continuous process worked out by Biazzi (Vevey, Switzerland since 1935) [42] includes a new type of acid-resistant steel nitrator (Fig. 47) and the application of tangential separators, the liquid content of which is constantly in motion. 

One of the first plants nitrating glycerine by the Biazzi process was in operation at Schlebusch in Germany [43]. For a plant with a rated output of 800-1000 kg nitroglycerine per hour a nitrator of 250 1. capacity was used. 

The flow sheet of a more modern Biazzi automatic plant is given in Fig. 48. 

According to the original description [44] glycerine and glycol are pumped to an intermediate tank (13). 

A metering pump introduces the required quantity of glycerine to the nitrator. 

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NG. Batch-wise production of NG is described in Vol 6, G99-102, and continuous methods such as the Schmid t-Meissner and Biazzi processes are discussed in Vol 3, C501 — 505. The Swedish injector process and the Hercules tubular nitrator will be described below, but before doing this we will discuss certain aspects of glycerin nitration that are common to both batch and continuous methods, and then contrast the main features of the batch process vs the continuous process... 

Gyttorp [Named after a small Swedish town] A continuous process for nitrating polyols to form nitrate esters, used as explosives. Similar to the Biazzi process. 

MF can also be manufd by Biazzi Process. Since it is not described in Vol 3 of this Encycl, pp C50lff, under "Continuous Methods for Manufacturing Explosives it is suggested that info be obtained directly from Dr Mario Biazzi, Ing, Vevey, Switzerland... 

However, largely because of doubts about the safety of the innovations proposed, they have not found acceptance and it was not until 1927 when the Schmid process was devised and 1935, when the Biazzi process was developed that these continuous production processes were recognized as efficient and safe. 

Acid nitroglycerine flows into a battery of stainless steel continuous washing tanks (3) and (4) provided with stirrers (580 r.p.m.). The first tank (3) is fed with 12% sodium carbonate solution. This is one of the characteristic features of the Biazzi process and represents a radical change in approach to the stabilization of nitroglycerine since for the first time the acid nitroglycerine is treated directly with sodium carbonate solution without previous water washing. The heat of neutralization in tank (3) is removed by means of a water cooling jacket. 

The great advantage of the Schmid-Meissner and the Biazzi processes is the small amount of separated explosive present in the plant at any given time—up to 10% (and 4% respectively) of the output per hour—the remainder of the nitroglycerine in the system is in a safe emulsified form. 

Klassen and Humphrys [49] quote data comparing the main features of the Biazzi process as compared with batch nitration. The most recent data [50] are given in Table 18. 

The Biazzi process has been applied to the nitration of other substances, to produce not only esters similar to nitroglycerine, but also for the preparation of such substances as PETN, cyclonite and TNT. 

The material balance of the Biazzi process is given below for 1000 kg of produced PETN [18] ... 

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

Hercules tubular pr[Pg.358]

The Biazzi Process. For many years, the process for preparing nitroglycerine has been carried out in small batch operations, and the procedure has varied only slightly. In recent years, a modem continuous process, developed by Mario Biazzi of Switzerland, has b n gradually replacing the older manufacturing methods. The apparatus (Fig. 12-12) consists of a nitrator, a separator, and three mechanically stirred washers. The entire... 

Calgary plant of Canadian Industries Limited. They give the interesting comparisons shown in Table 12-8 for the batch, and continuous processes. They also compare raw-material usage for the batch and Biazzi process, as shown in Table 12-9. 

The stirred flow reactor is frequently chosen when temperature control is a critical aspect, as in the nitration of aromatic hydrocarbons or glycerine (Biazzi-process). The stirred flow reactor is also chosen when the conversion must take place at a constant composition, as in the copol3rmerization of butadiene and styrene, or when a reaction between two phases has to be carried out, or when a catalyst must be kept in suspension as in the polymerization of ethylene with Ziegler catalyst, the hydrogenation of a-methylstyrene to cumene, and the air oxidation of cumene to acetone and phenol (Hercules-Distillers process). 

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