Hamed:
As moderator, I’ve taken the initiative to edit your post for punctuation, grammar, etc. - but no spelling. For that, everyone has SpellCheck. I did this to allow our members to understand your query better.
You are right; your English needs work on it - but so does your engineering. Why do you give the units of MW (molecular weight) as (KJ/Kg)? Isn’t the molecular weight given as kg/kg-mole or lb/lb-mole?
You state “how can I drive new curve for it”. Do you mean “draw” instead of drive?
If you intend to change the gas service of your existing centrifugal compressor, I can tell you from personal experience with centrifugal compressors that you should consult with and request a new compressor performance curve from the manufacturer, citing all the conditions and properties of the proposed, different gas you intend to compress. To redefine the new, proposed suction conditions on your machine and operate it as such is to take the total responsibility on your shoulders. I assume that, like me, you have never designed - nor much less manufactured a centrifugal compressor. Hardly anyone has. The matter of generating a new performance curve (if that is a possibility) is best left in the hands of the experts who designed and fabricated the machine itself. I have seen far too many mishaps with centrifugal machines in the past by persons who couldn’t interpret their performance curves and I would expect far more from those who generate their own performance curves. Centrifugal machines are great - but they have a multitude of trade-offs. This is just one of them. They are very specific in their design.