3 replies to this topic

[ayan_dg]

Can HIPS (High Integrity Protection System) be used to reduce flare header size / reduce PSV size ?
Can HIPS may be used to reduce downstream Design temperature ?

[Dazzler]

Hello Ayan

1. Properly implemeted HIPS can be used to eliminate some relief scenarios, and/or reduce the required relief flow for a given scenario. Various relief scenarios may apply for a pressure vessel or other system requiring overpressure protection.

Yes HIPS can therefore reduce the required size of a relief device. If relief devices are smaller (producing a smaller flow rate) then the header they enter might also be able to be reduced. The largest flow (or coincident flows) to a header (as well as the length of header) is however likely to be the one governing the diameter of the header.

2. It could be justified to alter the header downstream design temperature if HIPS is used to reduce a relief flow AND it always occurs at the same time as another flow. However, if the flow with an extreme high or low temperature is lowered but can occur under some scenarios on its own, then the downstream temperature will still be same. Sometimes a flare header has its material or specification changed much further downstream if a calculation is made that accounts for the heat loss or gain from the pipe to the environment.

Hope this helps. If you or someone judges my answer to be accurate and useful for those in future, please click the + button so I get my first reputation mark.

Thanks, Dazzler

[JoeWong]

Dazzler,
welcome...

ayan,

Please allow me to comment to your initial post. The questions are incomplete and not specific. Your will get a lot of answer inluding "yes. you can", "no. you can not", "yes. you may with the condition...", etc. All this link to risk level generated by your system and risk that your project or company can tolerate.

When you initiate your post, the better (i think) approach is that you
i) provide your problem statment as what you have done
ii) provide the background info including data
iii) tell us your opinion on your problem statement
iv) tell us your doubt on certain aspect

With these information, many occasion you will be able to answer large part of your question and advise us your understanding level on the topic.

1. Properly implemeted HIPS can be used to eliminate some relief scenarios, and/or reduce the required relief flow for a given scenario. This has been implemented in many projects but with a lot of additional requirement, action, etc to minimise and mitigate risks and consequences. In my opinion, there are some scenario HIPS may not practical to be implemented e.g. external fire.


2. Technically if you can justify to eliminate some relief scenarios by HIPS, theorectically you can justified to alter the header downstream design temperature if HIPS is used. However, in practical you may still reqiire to install a smaller PSV to cater for other scenario including fire or manual depressuring valve in the system. There is tendency of these valves to leak and lead flare/vent collection header seeing same temperature.

[ogpprocessing]

For one gas condensate refinery project I have seen the basic design engineer (Snam-Progetti) has considered 16 HIPS for the refinery to reduce the flare network capacity but at the same time considered failure of 2 out of 16 HIPS as a sizing scenario of the flare network.
Is it a proper trend?