6 replies to this topic

[mido]

I am now sizing PSV for free water KOD the operating condition is 40000 barrel water and 10000 only Bopd .the sizing case is fire as associated gas is only 2 MMSCFD. how can i calculate latent heat in this case .if i calculated it as the vessel is fill only with oil the PSV will be very large and actually the vessel will never operating at this case ?? I calculate latent heat for mixture using HYSYS it was a value near latent heat of water as a majority of feed is water >Can i use this mix latent heat value?

[Bobby Strain]

You didn't perform the proper calculation with HYSYS. You probably should ask your supervisor for the appropriate procedure.

 

Bobby

[mido]

Dear/Bobby
                    unfortunately we are production co and my supervisor don't have experience on that. Can you tell me how to do that?
Thanks

[Bobby Strain]

Mido,

   You should hire a professional to do the work for you. There are probably other areas where they can be helpful. Since you already have all of the information in HYSYS, it should be a simple task. And not expensive.

   I have never seen published a good, clear procedure to follow. You can probably develop one by applying your knowledge. You can write a description of what is happening during a fire. Your first try was not even close. The process of vaporization is incrementally generating vapor from the liquid pool. So, just develop a simulation on this basis. You can examine the process by considering flashes of a small percentage of the liquid, say 2%. So you will need to model many flashes, which is easy to do with HYSYS. If you generate such a dialog and sketch I will be happy to review it. And likely others will, too.

 

Bobby

[mido]

hysys have already tool calculating PSV size depend on feed flow. Can i depend on it , it seems calculate the procedure you said automatically. I attached the pic that illustrate the procedure of simulation from hysys help. https://ibb.co/0r9SjPb

[Bobby Strain]

Mido,

     That is the method that I use. Set the heat input to each stage to get 1-3% vapor generation. Then size the PSV for the vapor from each stage. Pick the largest area required. I have only an old HYSYS so this feature is lacking. I think I have an application to fetch streams from HYSYS and size a PSV. I'll look for it. Meanwhile, send me your email so that I can send it when I find it. Maybe the HYSYS module does this, too. But you should do a bit of independent calculation to assure yourself that HYSYS is correct.

 

Bobby

[mido]

dear bobby
                    i send you my mail in a message. very thanks to your help