Unloading tanker truck hose and pipe when loading point is lower then A/G tank nozzle

[curtis2004]

Hello colleagues,

I am reviewing a design of Light Oil system with a Light Oil storage tank. The system is used to store and distribute diesel fuel to emergency generators and auxiliary heating boilers.
My storage tank is about 80,000 liters with horizontal construction and have 6" loading nozzle on top (12 o'clock) position. I have three 3" unloading quick connect ports with isolation valves connected to a single 6" header (with check valve) which then goes up and connected to top nozzle of horizontal tank.
I have one issue: How do I empty my 6" loading line and unloading hose before decoupling it? I have heard that you need blow this line with low pressure air in order to push diesel into storage tank and empty hose and loading line. However, I have concerns if this safe procedure. Does standard tanker trucks have this feature (blowing air into their loading hose) or do I need to design this low pressure air system?
Does anyone have previous experience with this type of problems? Did we had any discussion before here? I do not think this is unique situation.

Thanks in advance for your time,

Curtis

 

[miningman]

Curtis, you have a problem with your temperature conversions. Minus 40C is exactly the same as minus 40F. Everyone in northern Canada knows this. Might not make a differrence to your engineering but this will destroy your credibility in the North if you repeat this error.

 

[curtis2004]

Sir,

Sorry I meant -50F = -46C. It is a typo.

Curtis

 

[LittleInch]

First off your flanges shouldn't be leaking!

Yes you need to insulate valves and flanges.

If you're worrid about leaks for some reason, add a half shell PE pipe under the flange and include a small drain pipe through the insulation - I've never seen it, but if it keeps everyone happy then it's cheap and does the job.

You want to get the best insulation you can - the trace heating will just eat $$$ if you don't

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