GB189815949A - Improvements in and Apparatus for the Manufacture of Sulphuric Anhydride. - Google Patents

Abstract

15,949. Johnson, J. Y., [Badische Anilin & Soda Fabrik]. July 21. Sulphuric anhydride.-Relates to an improvement in the manufacture of sulphuric anhydride by the contact process, consisting in passing the gases through the contact substance, preferably platinized asbestos, at a regulated temperature. One effect of the reaction of the sulphur dioxide and oxygen on the contact substance is to raise the temperature of such contact substance. This may even reach as high as a bright-red heat, at which temperature some of the formed sulphuric anhydride reverts to sulphur dioxide and oxygen. Several devices for regulating the temperature and thereby preventing this are illustrated and described. In the simple form shown in Fig. 1, a brickwork structure or iron tube M has a tube R fixed within it, leaving an annular space between the two. The contact substance is placed in the lower part b of the tube R. The temperature is raised, at the commencement of the operations, to the required limit by burners h. Cold air is then passed into the annular space through openings n, and carries the heat from the contact substances upwards, heating the upper part of the tube R on its way to the outlet L. Further heat may be imparted by burners h<1>. The purified sulphurous-acid gases enter the upper end of the tube R, become heated by passing through the part a, and then pass through the contact substance in the part b. Several tubes may be combined together. In the form shown in Fig. 2<a>, a number of reaction tubes R are filled with platinized asbestos, and are surrounded by an outer tube or chamber S, into which the gases are admitted from gas chambers A and A<1>. The chamber S is provided with partitions C having side openings to cause the gases to pass close to the walls of the inner tubes. The heated gases pass to a mixing- chamber N in the top cover D, to which also fresh cold gases may be admitted if desired, and thence pass through the tubes R, finally escaping from the lower cover D<1> to the outlet. Cold air passes, as before, through the annular space between the outer casing and the chamber S. External heat may be applied by burners h, by ordinary fires at h<1>, and by heating-apparatus G, the course and temperature of the gases being regulated by the valves V, V<1>, V<11> and by the heating-appliances so as to obtain the most suitable temperatures. The temperature in the cover D should be about 380‹ C., and in the lower cover D<1> about 234‹ C. By this arrangement, a conversion of 96 to 98 per cent. of that theoretically possible can be obtained, while making from 40 to 50 kilogrammes of sulphuric anhydride per tube in twenty-four hours.