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The main part of the system consists of a tall tower with two segments. Both segments are tall enough to the point where water cannot reach the top because it boils before it gets there. If water is taken from a well on one side, the water level inside the tower would take water from the sea in order
to even out, meaning you could continuously take water from a well and have it continuously refill with distilled water.
The problem of the distilled water having the wrong PH and dissolving the walls of the well could be solved by keeping mineral rocks in the clean side of the well and replacing them as needed.
The salt buildup would need to be cleaned from the other side of the tower periodically.
diagr
https://imgur.com/a/qBZzhN2
[flireferret, Dec 09 2024]
vacuum distillation
https://en.wikipedi...Vacuum_distillation
[Voice, Dec 09 2024]
[link]
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Given that both the salt side and the fresh side are exposed to vacuum, why would the rate of condensation on the fresh side exceed the rate of evaporation from that same fresh side? |
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//The main part of the system consists of a tall tower with two segments. Both segments are tall enough to the point where water cannot reach the top because it boils before it gets there. If water is taken from a well on one side, the water level inside the tower would take water from the sea in order to even out, meaning you could continuously take water from a well and have it continuously refill with distilled water.// |
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You want to force salt water up a tower to de-salinate the water and extract the salt using towers which won't allow salt to form below a certain atmospheric pressure?
If so...
...That kind of makes sense to me. |
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Ingeniously faulty. As usual the problem is finding the fault. |
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So the water column under a vacuum would only be a bit over 10m high or so. This is eminently doable. |
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Then yes it seems that the water at the top of the column would boil, releasing water vapuor into the space above the water column. This of course reduces the vacuum pressure and the column of water drops a little until we get an equilibrium between the boilability of the water and the pressure of the water vapour above it. |
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Then we make the second tower alongside and attach it to a fresh water reservoir, and we get the same situation (with a slightly different height of water column because of the different dentistry and boilability of fresh and salt water) |
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Excellent, we are making progress! We have two side-by-side towers, both with a water column, above which in both is pure water vapour, both in a stable equilibrium situation. |
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Next, we open the massive connecting valve that joins the tops of the two columns side by side. The pressure of the vapour above each column equalises, and the heights of the two columns slightly adjusts to equalise the pressure and boilability etc on both sides, and then almost instantly the system settles into a stable equilibrium situation. |
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I think this is the point at which [fireferret] starts cursing because the machine stops doing anything and just sits there in a stable equilibrium state. |
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Perhaps we then lower the bucket into the well, and draw up a bucket of fresh water. I think that the equilibrium state means that it is the --height of the water column above the surface of the water that is exposed to atmospheric pressure-- which remains constant. So the surface of the well water drops a very small amount, and the height of the fresh water column drops a very small amount, and the pressure of the vapour drops a very small amount, and a little more water boils off both sides, slightly increasing the vapour pressure, and the height of the seawater column then drops a very small amount. There is now very slightly less fresh water in the system plus bucket than there was before, and the system settles into its new equilibrium situation. If we ran very long and tedious calculations we may well find that exacly one bucket-full of sea water has come out of the seawater column and flowed back into the sea. |
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[flireferret] curses and draws another bucket, and the same happens again. Frenziedly, they extract bucket after bucket faster and faster and the water level keeps dropping until suddenly there is a gut-churning gurgle and a mahoosive bubble of air rushes along from the bottom of the nearly-dry well and up into the tower and both columns collapse with a despairing sigh and a gentle slapping of waves. |
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[Voice]'s link helps; it seems that you have to warm the salty side and cool the fresh side. And if you do that, it works. |
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Points to [poc] for Word of the Day: mahoosive |
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mate: Nip down the pub for a pint?
moi: After the jeezly jeezler day I've had, Imma needa MAHOOSIVE mug up! |
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