Hi Tom;
Your post made it to the list. There is a switch for self delivery did
you inadvetantly turn it off lately when changing settings for the list
server?
Anyways Ken says zeolite once in use will reliably only adsorb more like
10% of it's weight in water.
Sorry I thought you were running a vacuum processor like me. Yes the
line from the tank must be insulated. It is handy to insert a
thermometer beneath this insulation to monitor vapour temperature while
things proceed. A molecular sieve is normally fitted with a heated and
insulated jacket which allows it to be regenerated in situ using the
vacuum system to assist drying. Often these are used to prevent oil from
a mechanical pump backstreaming under molecular flow conditions ( below
50 millitorr as a general rule but depends on geometries) into the rest
of the vacuum system. In that case the sieve is fitted just upstream of
the pump. In our case I would put it just above the condenser at a
point where vapours can flow vertically downward through it. If I
really wanted to be clever I could build a fractionating column and use
the zeolite beads as the fractionating media and kill two birds with one
stone.
The process would involve recovering methanol and then as a final step
the trap would be heated and the vacuum pump used to dry the zeolite.
The water would then precipitate out and be collected in a separate
container from the methanol. The actual amount of water removed would
then be known. Process endpoint would be decided by an improvement in
the vacuum at a fixed pumping rate.
Best regards.
Let us know what you learn.
Joe
Thomas Kelly wrote:
> Joe,
> I got your response, but my post never appeared in my mail nor did any
> response w. numbers? from Ken.
> Maybe they'll show up in my spam trap later.
>
> 25 lbs (11.2 Kg) of 3A molecular sieve arrived a little while ago.
>
> You wrote:
> "You could put the seives in a trap upstream of your condenser. "
>
> Run the vapors through the sieve? Won't they cool and condense? I had
> to insulate the short tube leading to the condenser because methanol was
> condensing in the line before the condenser.
>
> Also:
> "If the trap is fitted with heater you can then heat them in situ with
> vacuum and dry them in place later ......."
>
> If you are talking about regenerating the zeolite, I'm thinking of a
> solar oven ... suggested by Todd. I have plans, materials, etc. Seems
> rather simple enough .... also, perhaps, too good to be true?
>
> Quite a bit of interesting stuff includes using vacuum pumps. I don't
> know how to use one ... that is, apply it to anything. There's a vacuum
> pump on sale at Harbor Freight for under $20 US. "Venturi-type vacuum pump
> removes water from air conditioning systems. ...... produces a vacuum of
> 28.3" of mercury at sea level w. 90 psi. .... 1/4" NPT." $15.99 (Same w.
> 1/2" connector $16.99). Do I need something better than a $20 pump to
> generate vacuum to help dry my WVO or for what you are suggesting here?
> Always good to hear from you. I hope Ken's numbers come through. I'd
> like to see them.
> Tom
>
> ----- Original Message -----
> From: "Joe Street" <[EMAIL PROTECTED]>
> To: <biofuel@sustainablelists.org>
> Sent: Tuesday, May 23, 2006 4:01 PM
> Subject: Re: [Biofuel] 3A molecular Sieve and Methanol recovery
>
>
>
>>Great news Tom;
>>
>>I'm waiting to hear what the weight change happens in your seives
>>material. Let it dry first as it will be wet with methanol on the
>>outside but the adsorbed water will not evaporate easily so air drying
>>should not result in apreciable water loss as long as you don't overdo
>>it. Ken's numbers may seem depressing but are probably realistic. You
>>could put the seives in a trap upstream of your condenser. If the trap
>>is fitted with heater you can then heat them in situ with vacuum and dry
>>them in place later when you get everything sorted out. However the
>>recovered methanol may be less than 10% water (I hope) so it would be
>>fine. I am holding my breath waiting to find out!
>>
>>Joe
>>
>>Thomas Kelly wrote:
>>
>>
>>>Hello to all,
>>> 3A molecular sieve is on its way. As I understand it, selectively
>>>absorbs water from a water-alcohol solution thereby drying the alcohol
>>>..... sounds too good to be true.
>>> In my previous attempt at recovering methanol from the crude
>>>glycerine split from the glycerine cocktail, a combination of greed and
>>>stupidity on my part resulted in methanol w. water in it. ("Water in
>>>Recovered Methanol?" 4/28/06).
>>> I've tweaked the condenser. I've tied the cooling of methanol
>>>vapors (----> much hot water) to my wash tank. Will use the hot water
>>>generated by the cooling of methanol to washing a batch of BD.
>>> I will keep close eye on temp. and be patient. Do not allow the
>>>temp to rise above 160F until distillation stops at this temp.
>>> Distillate produced in 150 - 160F range was mostly methanol. Temp
>>>increase seemed to slow down at 150F. I take this to mean a phase change
>>>is occurring (added heat is converting liquid Methanol to gaseous
>>>Methanol). Above 160F temp seemed to rise more quickly. I take this to
>>>mean that much of the methanol is gone.
>>> My plan is to have 4 containers, each with 5 lbs (~ 2.24 Kg) of 3A
>>>molecular sieve. Allow 2 gallons of distillate to flow into each
>>>container. Occasionally swirl the contents of the containers over the
>>>next 24 hrs.
>>> I'll strain out the 3A molecular sieve and re-weigh. If it works, I
>>>should be able to dry the methanol and from the changes in mass of the
>>>molecular sieve, get a sense of the actual volume of methanol I can
>>>reasonably hope to recover from a given volume of crude glycerine. I
>>>also hope to get a sense of the temp cut-off point.
>>> As I understand it, 3A molecular Sieve will absorb about 25% of its
>>>weight in water. If, for example the molecular sieve in container 1 (1st
>>>2 gal distillate) increases by 5%, the next by 8%, the next by 15%, and
>>>the last by 25%, and additional Mol. Sieve continues to gain mass, I
>>>would think that 6 or 7 gallons of methanol is a reasonable
>>>expectation for the volume of co-product I'm distilling.
>>> Suggestions ... including "Stop, you have it all wrong!"
>>>would be appreciated. It's tues. Friday looks like a good day to brew;
>>>Saturday, to wash/distill. There's time for suggestions.
>>> Tom
>>>
>>>
>>>------------------------------------------------------------------------
>>>
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>>>
>>
>>
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>
>
>
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