4 replies to this topic

[rakesh_16]

Dear forum,

 

we have underground tanks of 25 kl capacity. The submersible pump flowrate is 6 m3/hr. we had provided the tank with flame arrestor cum breather valve on one nozzle for blanketing purpose and fire safety. I have to calculate the breather valve sizing based on the vapor pressure present in the tank and how much nitrogen pressure will be required for blanketing the tank .

 

[proinwv]

Is there a question here?

[Dazzler]

It seems to me that the governing flow that the vent breather valve should be capable of passing (inwards or outwards) is the larger of the maximum pump in rate or maximum pump out rate.  

 

Depending on the inerting and venting control system or mechanisms, keeping an inert atmosphere during pump out can be achieved by having N2 flow inwards at similar or a little lower rate compared to the pump out, so air "suck-in" will be minimal (the difference between pump out and N2 inflow).  

 

The control system settings should be such that N2 does not normally flow into the tank if there is no pumping in or out.  That way you minimise N2 usage.

 

Dazzler  

Edited by Dazzler, 01 April 2017 - 12:42 AM.

[vissu]

I am a process engineer in a pharma Industry.I  have a query regarding flame arresters. During a batch process, Sodium borohydride addition is present. To arrest Hydrogen liberated fumes to atmosphere, we have arranged a flame arrester to condenser vent. Why we have to arrange it to condenser vent ?? why cannot we arrange it directly to reactor ?? For which type of compounds we have  to arrange flame arrestors???

Edited by vissu, 19 May 2017 - 09:54 AM.

[spchauhan12]

Dear Vissu,

 

                 

          Hydrogen gas being very light gas will try to escape from reactor immediately i.e. its residence time in vessel will be less .

 

Hence, Flame arrestor shall be provided at  Condenser Vent rather than than on reaction vessel.

 

 

Also, if vent of Condenser is left open without any Flame arrestor & there is lightening / spark generated due to  any maintenance work

 

( such as welding work), would lead a fire & explosion situation.

 

Please read below link to have more understanding:

 

http://www.wermac.or...e_arrester.html

 

 

Regards,

SP