4 replies to this topic

[Hai]

to all,

I need your help. I am evaluating the PSV and Rupture disc for the current dispersers. the fire case calculation has been done, but I need to calculate the required flowrate for the PSV and Rupture Disc in case there is a runaway reaction. Please help me to show me the calculation for required flowrate for runaway reation that allows me to determine the PSV and Rupture Disc.

thanks

[fallah]

Hai,

It is a complex phenomena and relieving rate determination for a runaway reaction absolutely depends on reaction degree, nature, rate,... and state of reaction products. I would want to refer you to sec. 3.4. Vent Rate for Reacting Systems; from "Gudelines for Pressure Relief and Effluent Handling Systems".

Fallah

[breizh]

Hai,

Take a look at this link and the cases studied . Regarding Run away reactions you will find information about the required basic data , in particular the energy using Thermogram .

http://www.safety-s2...4&op=v&idp=1522

Hope this helps

Breizh

[Hai]

thanks all.. i will study your information..

[Mark-TR]

Hai,

Run away reactions are very compIex as stated above, generally reactor are licensed unit.

There are a lot of assumption to be done in runaway reactions that might be tricky, they also may depend on the dynamic of the system and the complexity of secondary reactions.

Plus you have the accuracy of EOS, the accuracy of the model for reaction the that takes place, the nature of reactants and equilibrium may also change at relieving conditions.


In my point of view, there is a lot of incertitude while sizing PSVs for run away reaction, so I prefer not to take the risk.

Remember the fundamental rule of computer simulation:

bad input= bad output

I do not know the nature of your runaway reaction but if it is complex and you are working for an engineering, the best and safest approach is to ask the Licensor.

Edited by Mark-TR, 10 September 2012 - 08:39 AM.