[C]

This is a for a sulphuric acid plant project. I need to measure SO2 at the Bed outs. kindly let me know the best way to remove SO3 from the sample.

There are 4 beds. The sample pressure is in the range of 800 mmWC to 2200 mmWC. Temperature is in the range of 440 DegC to 540 Deg C.
SO3 is 5.95% and SO2 is 5.1% Rest is O2 & N2 in bed 1
SO3 is 9.5% and SO2 is 1.7% Rest is O2 & N2 in bed 2,
SO3 is 10.27% and SO2 is 0.7% Rest is O2 & N2 in bed 3
SO3 is 0.80% and SO2 is 0.06% Rest is O2 & N2 in bed 4

One of the possibility I am looking is to pass the sample through H2SO4 and then pass the sample through the water wash so that incase there is any carry over then it gets removed and then I can cool the sample and take it to the analyser.
Is this a good idea to go ahead

Let me know if there is any other better way to go ahead.

[curiouscat]

If you only need an analysis wouldn't something like a calibrated IR sensor work without separation?

If you did need to separate it a cold trap might work: SO3 ought to condense way before SO2 and the rest.

[C]

I need an extractive system for this purpose and hence the whole exercise. I want to remove SO3(majorly unstable component in the sample) to make sure that my SO2 analysis is not affected by anything.

Although moisture is not present in the sample, I am assuming that  in practical there might be some moisture in ppm level and it might affect the system over a period of time.

[curiouscat]

One of the possibility I am looking is to pass the sample through H2SO4 and then pass the sample through the water wash so that incase there is any carry over then it gets removed and then I can cool the sample and take it to the analyser.

If you pass through H2SO4 won't it absorb some of the SO2 as well? SO2 has ~10% solubility in H2O if I recall right?