Why so much o2 left after So2 to so3 conversion

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I've 12% of so2 & 12% of o2 (volume %)
This is what entering the v2o5 catalyst converter. After the last bed 4th bed we have only 560 ppm of so 2 , I.e 0.056% of so2 , but 10 % of o2 still remaining. If the equation says half mole of 02 required for 1 mole so2 . At least 6% of o2 must have consumed for 12% of so2.
 

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  • #2
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First, what's the composition of the rest of the feed? Second, what are you taking off as product? Third, what methods are you using for the O2 and SO2 assays?
 
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First, what's the composition of the rest of the feed? Second, what are you taking off as product? Third, what methods are you using for the O2 and SO2 assays?
Sir, a volume of gas 150knm3 contains 12% so2 , 12% of o2 & remaining nitrogen. This enters the catalytic converter has 4 beds. Catalyst is v2o5. The so2 % & o2 % entering the first bed is mentioned above. The conversation of so3 happens in each bed. Typical adiabatic conversion. We have done analysis of so2 & o2 in each bed outlet. Found so2 % is gradually decreasing as the conversion happens. At the outlet of 4th bed the so2 % is .056% & o2 % is 10 %.
 
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Sir, a volume of gas 150knm3 contains 12% so2 , 12% of o2 & remaining nitrogen. This enters the catalytic converter has 4 beds. Catalyst is v2o5. The so2 % & o2 % entering the first bed is mentioned above. The conversation of so3 happens in each bed. Typical adiabatic conversion. We have done analysis of so2 & o2 in each bed outlet. Found so2 % is gradually decreasing as the conversion happens. At the outlet of 4th bed the so2 % is .056% & o2 % is 10 %.
First, what's the composition of the rest of the feed? Second, what are you taking off as product? Third, what methods are you using for the O2 and SO2 assays?
First, what's the composition of the rest of the feed? Second, what are you taking off as product? Third, what methods are you using for the O2 and SO2 assays?
If 12 % of so2 completely converts into so3 it requires atleast 6%of o2. Almost 11.5% of so2 is converted into so3. But y still 4th bed outlet has 10% OF O2 is remaining.
 
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No water getting into the feed stream?
 
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No water getting into the feed stream?
Nowhere no oxygen & water is entering the stream
 
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Process temperature? How much V2O5 in the catalyst beds?
 
  • #9
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I've 12% of so2 & 12% of o2 (volume %)
This is what entering the v2o5 catalyst converter. After the last bed 4th bed we have only 560 ppm of so 2 , I.e 0.056% of so2 , but 10 % of o2 still remaining. If the equation says half mole of 02 required for 1 mole so2 . At least 6% of o2 must have consumed for 12% of so2.
Seems like something else is happening to the SO2, other than reaction with oxygen.

What else could you have in the system?
 
  • #10
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Either you have moisture in your gas/reactor and the SO3 is turning into H2SO4, or you have a leak and your gas is leaving. Either way, willing to bet your total flow IN is not equal to the total theoretical flow OUT. You're measuring everything in %s, which may not be comparable to initial and final conditions. Have to do stoichiometric material balances though, since mass/moles in does not equal out when it comes to reactions.
 
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