9 replies to this topic

[RUBABU]

Existing Produced Water Tank with Fuel Gas blanketing need to be provided with seal in the overflow line. Sketch for the overflow line from the tank is given in the attached excel worksheet. Kindly recommend suitable seal type in the overflow line.

Attached Files

•  Book2.xlsx   10.3KB   218 downloads

[fallah]

Existing Produced Water Tank with Fuel Gas blanketing need to be provided with seal in the overflow line. Sketch for the overflow line from the tank is given in the attached excel worksheet. Kindly recommend suitable seal type in the overflow line.

 

RUBABU,

 

In general, siphon seal type with proper design in pressure balance stand point would be the best option for mentioned overflow line...

[RUBABU]

Thanks Sir for your feedback. Sorry, just to re-confirm, by siphon seal type, you mean a U bend right?. Kindly elaborate on criteria for design w. r. t. pressure balance

[fallah]

Hi
Yes, a u tube can do the job. The design is so simple. Take the water level in u tube at balanced condition a little bit higher than half of the water column elevation equal to the tank design pressure...

[RUBABU]

Thanks Sir for your valuable feedback.

 

a. Kindly clarify for liquid seal height calculation should we take Tank Max. Operating Pressure (say 7.5" WC or Tank Design Pressure 10" WC, considering the following

Tank Operating Pressure: 3-6" WC

Tank PVSV Set Pressure: 8.0" WC

Tank PSV Set Pressure: 8.3" WC

Tank Design Pressure: 10" WC

 

b. Any particular reason why liquid seal height selected = calculated height + (1/2) calculated height?

[fallah]

 

a. Kindly clarify for liquid seal height calculation should we take Tank Max. Operating Pressure (say 7.5" WC or Tank Design Pressure 10" WC, considering the following

Tank Operating Pressure: 3-6" WC

Tank PVSV Set Pressure: 8.0" WC

Tank PSV Set Pressure: 8.3" WC

Tank Design Pressure: 10" WC

 

b. Any particular reason why liquid seal height selected = calculated height + (1/2) calculated height?

 

RUBABU,

 

a. You should take design pressure as a basis

 

b. Considering the pressures you mentioned are in gauge, the height of water inside U tube at balance condition should be higher than 5"; because even at tank design pressure condition the tank pressure cannot throw the water column away from U tube to communicate the tank vapor space to the atmosphere... 

[RUBABU]

Please advice if I have understood you right.

 

Even if Tank Operating Pressure reaches Tank Design Pressure 10" WC gauge, the water seal in the Overflow line would not break. Operating Pressure has to go beyond 10" WCG for the seal to break which will not happen due to PVRV & PSV.

[fallah]

Please advice if I have understood you right.

 

Even if Tank Operating Pressure reaches Tank Design Pressure 10" WC gauge, the water seal in the Overflow line would not break. Operating Pressure has to go beyond 10" WCG for the seal to break which will not happen due to PVRV & PSV.

 

RUBABU,

 

Yes, you are right...

[chemmu]

Dear All,

 

As per above input the tank design pressure is 10" WC.

So static head have to be around 9.98 inch ( by considering water)

should we consider straight height or should we consider 2 legs ( in U tube) of each 5inch ?

 

thanks.

[RUBABU]

Chemmu - you need to elaborate your query for others to understand. looks like for your case, you seem to already have an overflow line of 5" inch dia size. in that case, one no. of U seal would suffice. I don't understand why u need 2 such U seal unless you have 2 no. of 5" overflow lines