Blowdown with water vs water free basis

[bouk]

Hi,

Can anyone advise, as the results I am getting are confusing the theory I thought!

I did a blowdown in Hysys of a vapour phase stream with a fire case with water and then removed the water and normalised my components and did it on a water free basis.

I had thought that the water free basis would take less time to depressurise than the water present basis, but the opposite happened! Why would the water free basis take more time than the water present basis? (The latent heat of vapourisation of water is 2260 kJ/kg which is more than hydrocarbons)

Cheers

 

[PaoloPemi]

I have a different software (PRODE PROPERTIES) to simulate blowdown so I cannot say (from experience) if there is something wrong with your software,
what I can say is that starting with a liquid mixture of HC + water the latent heat of water should have a quite large impact (at least in my test cases) and if you are simulating that case (liquid water + HC) your software should show the difference,
differently better to contact technical assistance.