Winterized Air Coolers Refinery Applications

[giovanna65]

Hello.

Is it advisable to locate the headers out of the confined place.( cooler's cavity) in order to avoid the formation of explosive mixture in case of flange,tube,plug leakage ?

Thanks

 

[dcasto]

Are you talking the headers on the air cooled exchangers themselves or some other header?

In any case, the more open the piping the better, but if you have restriction of working room, put the headers in the enclosed area and install a gas monitor.
I'll bet if you look at the minimum air flow you'd get to the minimum 3 to 6 changes per minute.

 

[giovanna65]

Hello.

Thanks for your reply.

What I meant is the header boxes with the plug and tube sheets and the process nozzles.
The pressure is 1000 psi which may cause substantial leakage in case of tube rolling, gasket failure.

Is any guide lines about the locations of these headers..say spec's, rules,...etc ?

Do you think the the minimum air flow can handle these knid of leakage ?

Thanks Kindly

 

[dcasto]

Someone else can jump in to. Everyone relies on API 500 for electrical classification as a guide for how to look at gas entering areas, confined or open. If you put a cooler in a building and "confine" it, RP 500 says the owner must decide if connects will have leaks and the extent (paraphase of the opening sections) of leaks ect. Being conservative, and not unreasonalable for 1000 psi gas, the enclosed area would be classified as Class 1 div 1, so all arcing devices removed or contained. With proper air movement, chngea per minute, a class 1 di 2 is the recommended practice, so again controls required (I guess in your case the motors and administrative permits for entry).
In sumarry I'd start with API RP500. For the most part, controls on arcing devices and personel and their tools will be required and not a lot of equipment/design changes. What really kicks up the heat will be known , absolute sources of gas release, like relieve valves, vents, I personally put compressor packing, and mechanical joints (gasketed flenges or screwed). In my opinion, Tube failures, flanges, and plugs are not high risk for clean dry sweet gas and I'd secify a class 1 div 2 and not look back on an enclosed fan. If you add H2S or MonoCancer DiKillya as the gas, back up and treat it as highly hazardous a start adding engineering controls.