pressure or vacuum

[MikeEFix]

Problem:
Transfer 10k gallons of contents from one tank to another tank in 20min.
With contents velocity not exceeding 10ft/s

Assumptions: (Tanks and piping)

Both source and destination tanks have 11’ dia and 15’ straight side with ASME dish top/bottom heads rated at 75 psig / full vacuum. And are at the same elevation 20’ apart under 0 psig

A 6” sch 10 pipe from the bottom center outlet of one tank to bottom center of the other connects the tanks. The length of the 6” pipe is 20’

Assumptions: (Contents)
1500Cp
1.1 Sg
Contains 5% free Vinylidene Chloride

Contents is shear sensitive and cannot be pumped in the conventional sense. It will have to pushed or pulled or a combination of each

By opening the valve on the 6” bottom connecting line, gravity will push 1/2 the contents to the empty tank.
The vapor space in the destination that the content displaces is returned to the source tank via return line connecting the two tanks at the top.

I need recommendations as to what method to use to transfer the remaining contents.

 

[BigInch]

Is a gear or screw type pump not conventional?

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[MikeEFix]

I apologize if I was unclear
I cannot use a pump of any kind. I'm constrained to applying pressure or inducing a differential pressure

 

[Ashereng]

Wait until the other tank's level drops, and then repeat?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[BigInch]

Ash, great idea! Really, I like it.

Sorry no, maybe its my foggy brain. Is the product destroyed or adversely altered when pumped? I don't understand why it can't be pumped. Just curious.

And you can't pressurize the first tank either?

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[MikeEFix]

This material is essentially polymer globule in water it cannot be “pumped” until it is fully reacted and stabilized.

Sure, I can pressurize the source tank but a some point I'll have to relieve the pressure in that tank - that's the problem.

I don't want to have to vent off VC laden vapor

I thought maybe steam would work since it would just condense to water ...

Or a vacuum pump-- creating a vacuum in the destination vessel, discharging into the source vessel

 

[Ashereng]

Is the tank designed to take much vacuum? If not, you may buckle the walls.

If you can't pump, and pressure (from steam or otherwise) is a problem, then you really only have gravity left, no?

BigInch,

Yes, a bit tongue in cheek, but not much.

If you need 7 feet in the second tank, then you need 14 feet in the first tank to equalise. Once the contents is used, you repeat the process. Why won't this work?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[MikeEFix]

The vessels are rated for full vacuum

The entire contents of the source vessel must be transferred to the destination vessel
This is a batch process

 

[MikeEFix]

Looking for some "thinking out of the box" suggestions

 

[BigInch]

Ash, I liked your answer, because I thought it was entirely serious! He may wind up doing exactly that.



Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[zdas04]

Do you have a source of pressurized, compatible gas? If so you can use a blow case. If you don't know what a blow case is it is a vessel that is vented to the draining vessel (or atmospher if it is a tank) with a fill line containing a check valve until it fills. When the level controller kicks in, a 3 way valve repositions and blocks the vent and sends pressurized gas to the top of the blowcase (shutting the check valve) and a dump valve opens and the gas pushes the blowcase contents into the second vessel. You can size the blowcase to contain the first vessel or to do the job in several steps.



David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[budt]

Why not mount the Source Tank at a higher level than the Receiver Tank and just open a valve between them when you are ready to transfer liquid.


Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com

http://www.fluidpower1.us

 

[iainuts]

The vapor space in the destination that the content displaces is returned to the source tank via return line connecting the two tanks at the top.

I need recommendations as to what method to use to transfer the remaining contents.

What type of vapor is this? Can you take the vapor from the destination tank and compress it into the source tank? By moving the vapor instead of the liquid, you'd pressurize the source tank using this vapor and not have to put any pump into the liquid line.

 

[25362]

Have you considered peristaltic pumps or Tesla-type pumps ?

 

[Ashereng]

Hi Mike,

Sorry. I just read the OP again and yes, you did say full vacuum.

15' of SG 1.1 is about what, 50 psi? Sorry, don't have anything but esitmates in my head.

At full vacuum, you still only have 14.7 psi, so I don't think creating a vacuum in the second tank will work.

A blow case will still require a gas of some sort, and you still have to deal with getting rid of the gas unless it can go down stream with the process fluid - and it seems that this is not desireable.

I still think that gravity is your best cheapest solution - if you can live with a heel in the first tank.

You mentioned that this is a batch operation - I still don't understand why you can't half the batch size?

Oh, one other question. How are you filling up the first tank? And why can't you do the same to the second tank?



"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[25362]

Then, there is still the old and reliable Archimedes screw to lift the liquid suspension to the full tank height to maintain gravity flow from the highest point.

 

[StephenA]

Thinking outside the box, what about a bladder in the first container which you could fill with water, or make the first tank a cylinder (it is already being circular) and use a giant piston. The old gasometers spring to mind as well.

 

[katmar]

In the same line as 25362's screw lift, what about an air-lift pump? If the two tanks' vapor spaces are connected, you could pull vapor from the first tank and blow it into the bottom of the air-lift's riser. The pumped liquid would then gravitate from the catch weir at the top of the riser down to the second tank. This would make it totally self-contained with no external source of vapor required, and no need to vent vapor anywhere. The airlift pump could be installed between the two vessels with the liquid feed coming from the bottom of the first tank, and the vapor spaces of the two vessels and the pump all being connected together.

This would probably not be as energy efficient as the screw lift, but it would have the advantage of not requiring any mods to the vessels.

Harvey


Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[MikeEFix]

I will need ½ negative atmosphere in the destination tank and ½ an additional positive in the source to move all the contents after the level in both tanks have equilized.

Looking at screwli9ft systems and steam air ejector that discharges to source vessel.

 

[scastillo]

Would a piston-filler type arrangement work? Let gravity take care of the first half and the piston-filler handle the rest.