Hordenkontaktkessel mit Ringwaermeaustauscher

摘要

A multiple contact bed converter for the catalytic conversion of So2-containing gases into So3, comprises at least three contact beds and an intermediate heat exchanger annularly surrounding the first contact bed and directly adjacent thereto and so arranged that when the converter is in operation, the gases leaving the first bed flow through the heat exchanger to the second bed. As shown, So2 gases having been conventionally preheated to approximately 320 DEG C. by heat exchange with So3 gases leaving the converter through an outlet opening 13, enter an annular chamber 2 through an inlet 1. From this chamber they pass into a heat exchanger 21 which annularly surrounds the contact beds 4, 6 and being guided by baffles 22 sweep around a U-shaped flow path defined by hairpin tubes of the heat exchanger in cross flow. The temperature of the So2 gases having thus been raised to 440 DEG C., they then pass through a preliminary catalyst bed 4 via opening 5. The precatalyzed So2 gases are then mixed with cold So2 gas or air the latter being admitted through pipe 14 and distributed by mushroom head 15 and outlets 16. Simultaneously hot precatalyzed gases are passed through space 19 and thorough mixing ensues. The mixed gases then pass through a first catalyst bed 6 and enter the annular heat exchanger 21 through peripheral openings 7 at a temperature of 510 to 540 DEG C. Whilst flowing through the hairpin tubes of the exchanger their temperature drops to 430-450 DEG C. After having passed through the heat exchanger the cooled contact gases are taken through intermediate openings 8 to a second catalyst bed 9 from which they flow out through a pipe connexion at 10. In a separate intermediate cooler (not shown) the largely pre-catalyzed gases are cooled to the working temperature of a third bed 12. This temperature, as known, is kept as low as possible, e.g. 410-420 DEG C. After maximum reaction in contact bed 12 the contact gases leave the converter through outlet 13 and are then used in conventional manner for preheating the So2 gases in further heat exchangers likewise not shown. Specification 925,827 is referred to.