DE2213579B1 - METHOD FOR CATALYTIC CONVERSION OF GASES WITH HIGH CONTENT AT SO LOW 2 - Google Patents

Description

Stream B is processed further in a known manner.

The advantages of the invention are that when the catalyst is inactivated, the conversion to SO _{3 is kept} practically constant, the amounts of gas also remain practically constant, and optimal and simple operation is thereby possible. In addition, fluctuations in the gas composition of the stream Λ can be largely compensated for.

1 sheet of drawings

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Claims (1)

1 2 Catalyst mass as theoretically required - how Claim: it applies to the processing of gases with an SO ₂ - Content below about 11% is common - is with gases Process for the catalytic conversion of high SO ₂ content is not possible because the gases with a high SO ₂ content are in contact with 5 reaction before reaching the critical temperature for the catalyst and thus considerably before contact trays, with a partial flow being partial When the equilibrium is reached, converted SO ₃ -containing gases must be _{broken off to the SO 2 -containing gases.} Gas before use in the first contact tray The invention is based on the object is admixed and the gases are intercooled between contact io reduction of the conversion to SO ₃ due to Inhorden, thereby preventing activation of the contact mass,
characterized in that at least one part of this object is achieved according to the invention Stream of the branched off partial flow partially dissolved, that at least a partial flow of the branched-converted SOg-containing gases is _{passed through an absorber before the partial flow of partially converted SO 3} -containing mixture is passed through an absorber and the amount of SO _{3 absorbed before admixing} is conducted in dependence and the _{amount of SO 3} absorbed, depending on the increasing inactivation of the dependence on the increasing inactivation of the clock mass is increased in such a way that the contact mass is increased in such a way that the conversion of SO ₂ to SO ₃ in the contact trays conversion of SO ₂ to SO ₃ in the contact trays remains approximately constant. 20 remains constant. The entire branched off substream is preferably passed through the absorber. This is not necessary a regulated diversion and admixture. The invention is explained in more detail with reference to the figure and an example. The invention relates to a method for cata- The contact kettle 1 contains four contact trays 1 a lytic conversion of gases with a high content up to 1 d. Between the contact trays, there are intermediate SO ₂ in contact systems with several backcoolers 2 a to 2 c . With 3 is a cooler, interconnected contact trays, with a part with 4 _{denotes the absorber and 5 denotes the mixing device stream of partially converted SO 3} -containing gases. The flow of gases with a high content of SO ₂ -containing gas before use in the first SO ₂ is passed into the mixing device 5. The contact tray is mixed in and the gases between Stream E of the mixed gases are intercooled in the contact tray. boiler 1 and goes through the When converting SO ₂ -containing gases to contact tray 1 α to 1 d and the intermediate cooler 2 a SO ₃ with subsequent sulfuric acid production, 35 to 2 c. The stream B leaving the contact vessel 1, the catalyst mass through the gas first of all to the gas partially converted to SO ₃ , is brought to the so-called light-off temperature. Cooler 3 cooled. A substream C of the stream B This light-off temperature is, for example, in the case of cata- lysts. It is passed into the absorber4 and freed _{from SO 3 there in a regulated one on the basis of vanadium pentoxide (V 2} O ₅ ) depending on the amount. The stream Ό leaving the absorber 4 according to its composition and method of manufacture at 40 is passed into the mixing device 5 at about 400 to 450 ° C. During the conversion of SO ₂ , where it is mixed with the stream. An increase in temperature occurs to SO ₃ , since substream F of substream C can cause absorber 4, the reaction is exothermic. In the case of gases, deal with one (shown in dashed lines).
With a SO ₂ content of up to about 11%, the reaction occurs. at temperatures in the range of about 620 ° C, for example Standstill, because then the equilibrium of the reaction The flow is 50,000 Nm ³ / h and has a SO ₂ + Va O ₂ ^ SO _{3 is} achieved. For gases with a composition of
With higher SO ₂ content, the temperature rises further,, -Q ₀ , ~ q since the reaction only takes place at higher temperatures oq ₀ / q ² comes to equilibrium. At temperatures above 50 remainder ° N ² around 620 ° C, however, damage to the ^2nd Catalyst. A partial flow C of 5000 NmVh is constantly being generated It is known that the damage to the catalyst is diverted entirely or partially by the sequence Avoid overheating in that the sorber 4 is directed. Gases containing SO ₂ before being used in the first 55 In the first year, no SO ₃ ab contact tray SO ₃ -containing gases will be mixed in in the absorber 4. sorbed. The stream £ then contains 3.37% SO ₃ , the admixture of the SO _{3 has the} effect of braking ; the stream B contains 22.14% SO ₂ and 37.14% SO ₃ .
Conversion of SO ₂ to SO ₃ , so that in the second year there are 30% SO _{3 in the absorber 4} the admixture and the corresponding residence time of the absorbed. Stream E then contains 2.33% SO ₃ , gases in the contact trays cause overheating, and stream B contains 22.41% SO ₂ and 36.34% SO ₃ . is avoided (German Auslegeschrift 1054431, In the third year in the absorber 4 60% SO ₃ German patent 504635, German open-absorbed. The stream £ then contains 1.32% SO ₃ , specification 2026 818). As the contact mass - the stream B contains 22.68% SO ₂ and 35.56% SO ₃ . especially in the first contact trays - in the fifth year in the absorber 4 100% SO ₃ Becomes inactive over time, leaves the reaction 65 absorbed. Stream £ then contains no SO ₃ , the rate of the reaction SO ₂ + V2 O ₂ ^ SO _3. Stream B contains 23.03% SO ₂ and 34.54% SO ₃ .
accordingly gradually and the gas turnover to SO ₃ The total turnover of the plant remains practically wrestles accordingly. The use of more constant at 60%.