- The incoming pressure ( On the left side of the filter ) is maintained by the pump,
- and the SNUBBER (On the right side of the filter ) can be a regular ball valve, a
proportional pressure relief valve or needle valve.
- The idea is to get the pump to build a pressure that is NEAR the
incoming pressure, forcing a "maximum" of the water molecules to pass
through the membrane, and thus cause the larger ethanol molecules to
flow to the end of the membrane and exit to the return line.
- Rememeber RO is not a screen, that will let one size of marbles drop
through, and retain the larger marbles.
- Molecules behave very differently in that they are micro elements
held together by a hurendous force and we can visualise them a bit
like the solar system: If you werer trying to pass the solar system
through a hole that would be slightly smalller than the CRITICAL
diameter of the solar system, the planets would move in a way to
align themselves, according to the pressure applied by a very big
- So: The more pressure, the more sqwishing and sqwshing would happen
until the planets finally pass through the hole.
- Molecules behave somewhat like that, and, depending on the pressure
applied, and even, a pressure difference of as little as 1/2 Psi can
make a big difference.
- Now here is the catch:
1) Define the "FEED" pressure: Mostly based on the type of membrane
2) Define the "SNUBBER" or hold back pressire: Defined by the
membrane wall permeation capacity, without crushing or distording.
3 ) Define the flow proportion of the feed rate to Ethanol and Water
- The membrane will perform as: Take some from here and give a little
there to end up with some of your wanted product at the end.
- And just the same as if you were trying to distill at a temperatures
that would be 2 to 3 degrees above or below the target temperature,
you would either get nothing or get something way out of whack.
- And we had better get our fine tuned brainstorm hats on to get all
the data, needed and the experimenting started.
BY THE WAY: The presures indicated by the gages are for
representation only aime at explaining the principle and are not
precise pressure indications.