Is this only the liquid release or two phase release scenario?

[chemks2012]

Dear all,

I need your help again.
If I have a reactor content (total capacity of reactor 12m3 and working capacity is 10m3) temperature of 120degC and if a coil carrying cooling water at 10degC fails under liquid surface. It seems like two phase release case? If so, I am not sure how to calculate two phase rate in this case. I would have water real ease rate of 10,000kg/hr.
Thanks in advance.
KS

 

[chemks2012]

Any pointers please?

Thanks

 

[Latexman]

A dynamic process simulator would probably be the most rigorous way for you to get the answer.

If that is not possible, do a heat and material balance with initial conditions at time = 0. That will be your worst case. Then, do a H&MB at 1 minute, 2 minutes, 3 minutes, etc. to see what will happen.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[sshep]

For tube rupture cases on exchangers, the leak rate (needed to calculate the relief rate) is based on the phase in the tubes, and then flashed for the relief valve rate. The leak area is estimated by assuming the tube sheers off, and flow is from both directions into the other side of the exchanger. By similar reasoning the most conservative model is that the water will discharge as liquid into the reactor, and flash into vapor only after contacting the process.

What is the reactor pressure?

best wishes,
sshep

 

[chemks2012]

Thanks Latexman and sshep,

The reactor will have blanket nitrogen at 0.5barg maximum so I would say reactor pressure is 0.5barg.

Thanks
KS

 

[sshep]

Hey chemks2012,

I can see that latexman and myself had different interpretations of your question.

I take it that you are concerned about a cooling tube rupture in the vessel, and wondering what reasoning to use to calculate the leak rate. Given the relatively low reactor temperature and slightly elevated pressure, and chilled water inlet temperature, I believe that a single liquid phase water discharge into the reactor is totally appropriate. If pressurized hot water were leaking into a high temperature low pressure reactor, then it might be more complicated, but your situation seems simple. In any case a single liquid phase is the highest and most conservative leak rate.

If I am not interpreting your question right, please rephrase.

best wishes,
sshep