PRODUCTION" OF SULPHURIC ACID. 7 



Blau 1 proposed to cool the gases in the first chamber by injecting a 

 spray of cold sulphuric acid, and in order to obtain the optimum 

 yield of acid from the gases in the subsequent chamber their tempera- 

 ture is raised by injecting sprays of warm sulphuric acid. 



Falding's process 2 has for its object the segregating of the active 

 gases in a system. To accomplish this he employs a chamber the 

 height of which is approximately one and one-half times greater 

 than its horizontal dimensions. The burned gases after passing 

 through the Glover tower in the usual way are introduced either 

 near the top or lower down on the chamber's side. Since the fresh 

 gases are hot, not only because they have recently issued from the 

 pyrites burners but because of the reactions taking place between 

 some of the constituents, they collect in the upper part of the chamber 

 in a relatively active layer. 



As the reactions subside the spent gases gradually cool and settle 

 to the bottom of the chamber, where they are withdrawn. Falding 

 claims that by using the high chamber a zone of great chemical 

 activity is always maintained in the upper part of the chamber, 

 and that the spent or inactive gases, which in ordinary chamber 

 systems act as diluents, are continually being removed from the 

 active zone. It is also claimed that much less chamber space is 

 required to complete the reactions by this process, so that even 

 where large volumes of gases are handled each chamber is a unit in 

 itself, being connected directly with the Glover tower instead of in 

 series as in ordinary chamber systems. 



A number of plants in this country are equipped with chambers 

 of this type and it is reported that the process is commercially suc- 

 cessful. 



The mam objections to the Falding system, in the opinion of the 

 writer, are, first, that no provision is made for obtaining an intimate 

 mixture of the gases other than the preliminary mixing brought 

 about in the Glover tower, and, second, that no adequate means is 

 provided for the condensation of. the acid mist formed by the re- 

 actions. 



The most widely used method of mixing and cooling the reacting 

 gases is by means of intermediate towers containing plates, tubes, or 

 baffles of some acid-resisting material cooled either by water, air, 

 or dilute sulphuric acid. A number of different types of towers 

 have been designed, but mention is here made of only a few of the 

 better-known designs. 



Lunge's plate tower 3 consists of a shell of lead either cylindrical 

 or angular in form and filled with a series of perforated plates laid 



1 German patent No. 95083. 

 2U. S. patent 932771 (1909). 

 3 Treatise on Sulphuric Acid, vol. 1, Pt. I, pp. 478-498. 



