DE2213579C2 - Process for the catalytic conversion of gases with a high content of SO deep 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 , the gas, is kept practically constant

quantities also remain practically constant and thus an optimal and simple operation is possible. In addition, fluctuations in the gas composition of stream A can be largely compensated for.

1 sheet of drawings

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 Vn 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 Once the equilibrium has been partially reached, the _{gases containing SO 3} converted to the SO ^ -containing must be broken off. Gas before use in the first contact tray The invention is based on the object is admixed and the gases are cooled 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 stream is partially resolved that at least a partial stream of the branched-converted SOj-containing gases is _{passed through an absorber before the incoming partial flow of partially converted SO 3} -containing mixture is passed through an absorber and the absorber SO ₃ - Amount is conducted as a function of the amount 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 kata- 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 are between SO., In contact systems with several backcoolers 2α to Ic . With 3 is a cooler, interconnected contact trays, with a partial with 4 the absorber and with 5 the mixing device stream of partially converted SO _? -containing gases denoted 30. The stream A of the gases with a high content of SO ₂ -containing gas before being used in the first of SO., Is passed into the mixing device 5. The contact tray is admixed and the gases between Stream E of the mixed gases will be intercooled in the contact tray. boiler 1 and goes through the When converting SO, -hahigen gases to contact tray 1 α to 1 rf 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 down. A Teilstrcn C of the stream B This light-off temperature is z. B. in the case of cata- lysts is passed into the absorber 4 and freed _{there in regulated gates based on vanadium pentoxide (V 2} O.) ic ter amount of SO _3. The stream D leaving the absorber 4 at 40 ° C according to its composition and method of manufacture is passed into the mixing device 5 at around 400 to 450 ° C. During the conversion of SO ₂ , it is mixed with the stream A there. 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).
So., - content up to about 11 Vo the reaction occurs. at temperatures in the range of about 620 ° C, for example Standstill, because then the equilibrium of the reaction The current A carries 50,000 NmVh and has a SO ₂ -t- Ά O ₂ ^ SO _{S is} reached. For gases with a composition of
With higher SO ₂ content, the temperature continues to rise, ^ q _{0 /} <jq since the reaction only takes place at higher temperatures _1fl0 . q ■ comes to equilibrium. At temperatures above 50 rest ° N ' around 620 ° C, however, damage to the - 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. SO., - containing gases before use in the first 55 In the first year, no SO., Ab contact tray SOj-containing oases will be mixed in in the absorber 4. sorbed. The stream E then contains 3.37 "-Ό SO _{; i} , der The admixture of the SO ₃ causes a braking of the stream S contains 22.14" / o SO ₂ and 37.14 ⁰ O SO ₃ .
Conversion of SO ₂ to SO ₃ , so that in the second year, 30% SO _{3 are in the absorber 4} the admixture and the corresponding residence time of the absorbed. The current then E contains 2:33 ° / o SO comparable _3, the gases in the contacting trays overheating 60 of the stream B contains 22.41 ⁰ Zo SO ₂ and 36.34 Vo SO _3. is avoided (German Auslegeschrift 1 054 431, In the third year in the absorber 4 60Vo SO ₃ German patent 504 635. German open-absorbed. The stream then contains 1.32Vo SO ₃ , specification 2 026 818). As the contact mass - the stream B contains 22.68Vo SO ₂ and 35.56% SO ₃ . especially in the first contact trays - in the fifth year, 4 100 Vo SO _{3 are in the absorber} In the course of time it becomes inactive, the reaction 65 is absorbed. Stream E then contains no SO ₃ , the rate of the reaction is SO ₂ + V ₂ O ₂ ^ SO., Stream B contains 23.03 Vo SO ₂ and 34.54 Vo SO ₃ .
accordingly gradually and the gas turnover to SO ₃ The total turnover of the plant remains practically ritates itself accordingly. The use of more constan; at 60Vo.