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Methanol Storage question
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I have my 55 gal drum of methanol stored in my unheated/cool shed. My question is - once I put on the lever action drum pump to pump the first batch, will leaving the pump on allow the methanol to evaporate? Do I need to pull it out and seal the bung after each use?
 
Registered: February 06, 2008Reply With QuoteReport This Post
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It's a good idea to remove the pump each time. If the pump doesn't completely seal the drum when it's installed, moisture can be absorbed from the air over time; especially if you live in a particularly humid area. If you're using your methanol fairly fast (ie. within a month), it's probably not going to be a problem, but it's still advisable to pull the pump & reseal the drum after each use to keep the methanol from absorbing too much moisture.

-Graydon




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Location: Utah | Registered: October 08, 2004Reply With QuoteReport This Post
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I keep mine closed between uses. I have two; one for recoverd methanol and one for fresh. I mix 20% recovered to 80% fresh per batch. I use a level action pump that is removed after each use.



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Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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I use a Harbor Freight hand crank pump. I stuff an old rag in the spout after each use to seal it back up. I haven't noted any problems yet.
 
Location: Chambodia | Registered: December 31, 2007Reply With QuoteReport This Post
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quote:
Originally posted by Eurocab:
I use a Harbor Freight hand crank pump. I stuff an old rag in the spout after each use to seal it back up. I haven't noted any problems yet.


If keeping the MeOH dry is your concern, then a rag won't help in the longterm. Use a dessicant filter.


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Location: Ukiah, CA USA | Registered: September 19, 2001Reply With QuoteReport This Post
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Vane pumps, like the hand crank HF pump, are positive displacement pumps. That also means the drum contents have zero access to the atmosphere with the pump installed. Like sealed.

We could have a whole other conversation about if it's good for the pump or not, but it does seal the drum, at least the hand crank rotary vane style pump.


HTH,

troy
 
Location: north america somewhere close to the midwest, or not | Registered: May 29, 2004Reply With QuoteReport This Post



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quote:
Originally posted by troy:
Vane pumps, like the hand crank HF pump, are positive displacement pumps. That also means the drum contents have zero access to the atmosphere with the pump installed. Like sealed.

We could have a whole other conversation about if it's good for the pump or not, but it does seal the drum, at least the hand crank rotary vane style pump.


HTH,

troy


Yes and no. They rely on seals that are often not biodiesel compatible. Methanol compatible? Some more than others. I've certainly seen them leaking before.


Kumar Plocher
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Location: Ukiah, CA USA | Registered: September 19, 2001Reply With QuoteReport This Post
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quote:
If keeping the MeOH dry is your concern, then a rag won't help in the longterm. Use a dessicant filter.


Perhaps a dessicant filter would work better, but like I said no problems with the rag thus far. I am now on my 6th 55 gallon drum. Wink
 
Location: Chambodia | Registered: December 31, 2007Reply With QuoteReport This Post
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quote:
Originally posted by troy:
Vane pumps, like the hand crank HF pump, are positive displacement pumps. That also means the drum contents have zero access to the atmosphere with the pump installed. Like sealed.

We could have a whole other conversation about if it's good for the pump or not, but it does seal the drum, at least the hand crank rotary vane style pump.


HTH,

troy

I have 3 rotary vane hand crank pumps, one a plastic chemical style and the other 2 cheapy steel pumps. All 3 have an air gap around the bushing that threads into the drum head, I would assume this is to allow air into the drum so that the liquid can get out?
In any event you could seal the bushing and see if a vacuum is created in the drum while pumping.

I always remove mine but it would be nice to leave it in so if you try sealing it up post back and let us know your results....
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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I use the inexpensive HF rotary pump. When I install the pump I seal the bushing with silicone. The pump does indeed create a vacuum when drawing.
I keep a synthetic wine cork in the pump when it is not in use.


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Location: Southern Indiana | Registered: June 26, 2006Reply With QuoteReport This Post
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I'm wondering if condensation in a metal barrel is an issue with methanol when it cools outside. I live in AZ and in the winter in Phoenix we can have a 30 degree change and there is condensation on a lot of things. Would a plastic barrel be better?


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Registered: November 13, 2014Reply With QuoteReport This Post
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Hi azjed,

quote:
Originally posted by azjed:
I'm wondering if condensation in a metal barrel is an issue with methanol when it cools outside. I live in AZ and in the winter in Phoenix we can have a 30 degree change and there is condensation on a lot of things. Would a plastic barrel be better?
As lond as the barrel is sealed tight, the only thing that will condense inside the barrel is what is already in the barrel.
There is no problem as long as everything is sealed tight.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post



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quote:
Originally posted by Jon Heron:
I have 3 rotary vane hand crank pumps, one a plastic chemical style and the other 2 cheapy steel pumps.


I tried one of the plastic chemical-safe rotary pumps as well, and had absolutely terrible luck with it -- I don't think it lasted two batches. Maybe mine was an anomaly, or maybe they're not as chemical-proof as advertised. My "cheapy steel pumps" have delivered better over the years. I used to use the cheapies for raw oil collection at some locations.

For methanol dispensing and final fuel dispensing, I prefer air-operated pumps. Quiet, easily controlled, and no moving parts to fail.

Cheers, John
 
Registered: June 17, 2007Reply With QuoteReport This Post
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Thanks!
quote:
Originally posted by Tilly:
Hi azjed,

quote:
Originally posted by azjed:
I'm wondering if condensation in a metal barrel is an issue with methanol when it cools outside. I live in AZ and in the winter in Phoenix we can have a 30 degree change and there is condensation on a lot of things. Would a plastic barrel be better?
As lond as the barrel is sealed tight, the only thing that will condense inside the barrel is what is already in the barrel.
There is no problem as long as everything is sealed tight.


1997 Dodge Ram 2500
 
Registered: November 13, 2014Reply With QuoteReport This Post
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This is the pump I have for methanol.
I have used it for years and several dozen drums. The only mod I did was to add a length of 3/4" braided tube to the spout to make filling the containers easier. I keep the drums closed tightly and open them only when I need to pump some out.



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Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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Technically, if the drum isn't sealed perfectly, then yes, the methanol will absorb moisture from the air.

Methanol has a head-pressure, albeit small, and will slowly evaporate out of the drum. The speed of that evaporation is temperature dependent.

If the methanol is warm, like on a hot summer day, then it can absorb moisture upon cooling when the flow of vapors is reversed. As the methanol cools and contracts, it can suck in outside air and if that air is moist, the methanol will accumulate water.

That said, you'd have to leave it open to the atmosphere for quite a long time or be located in an uncomfortably hot environment for that to happen to a significant degree.

Assuming you have a pinhole opening, it would probably evaporate a coffee cup per week at 70degF.. Just an off the cuff estimation. Not a big deal.

Much more worrisome would be the evening cooling when the vapor flow through the pinhole reverses and it starts sucking in the evening air filled with moisture (dew). While I doubt a week's worth of this activity would make any difference to a full drum of methanol, leaving it that way for several months could create a problem. Folks down in dry areas like Arizona would probably never notice anything even after a year (except evaporation), but folks in Georgia, (extreme humidity and heat), would probably start noticing water contamination within a couple weeks.

When folks see problems with their biodiesel production and trace the causes back to their chemicals, its almost never a case of bad methanol.. Instead, its almost always related to bad catalyst. Your hydroxide will suck the moisture out of the air so fast it will almost create its own weather pattern. We're talking minutes here.. literally minutes before an open container of hydroxide will begin to get that "shine" on its surface. That shine is water.


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Registered: March 09, 2006Reply With QuoteReport This Post
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Hi Murphy,

quote:
Originally posted by murphy,
Methanol has a head-pressure...
Please explain what you mean.

A question to ponder.
If the ambient air temperature is 70F and I fill a closed-top 55 gallon drum that is at 70F with methanol that is at 70F and then seal the drum tight and maintain the temperature at 70F, will pressure build up in the drum?

quote:
Originally posted by Murphy:
Assuming you have a pinhole opening, it would probably evaporate a coffee cup per week at 70degF.. Just an off the cuff estimation.
In other words, you are just making a wild guess based on limited knowledge and no testing. Wink

This message has been edited. Last edited by: Tilly,






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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quote:
Originally posted by Tilly:
Hi Murphy,

quote:
Originally posted by murphy,
Methanol has a head-pressure...
Please explain what you mean.

A question to ponder.
If the ambient air temperature is 70F and I fill a closed-top 55 gallon drum that is at 70F with methanol that is at 70F and then seal the drum tight and maintain the temperature at 70F, will pressure build up in the drum?

Here you go:
http://avogadro.chem.iastate.edu/MSDS/methanol.htm
Scroll down to section 9.. see "Vapor Pressure"

The most commonly noticeable example of vapor pressure can be seen in a common household 6 gallon plastic gas can. Put some gas in it and leave it outside on a summer day and watch how the sides bulge out. Pop off the air vent and you'll hear the hissing sound as the vapor, under pressure, escapes.

Tilly, If you're interested in learning about liquid vapor pressures and their characteristics at different temperatures, I would suggest using google.


quote:
In other words, you are just making a wild guess based on limited knowledge and no testing. Wink


Well ya, I only have about 25 years of industrial processing knowledge and experience with Isopropyl alcohol and ~8 years of experience with methanol. Granted, Isopropyl alcohol has a lower pressure than methanol but I think I am capable of extrapolation and forming an "off the cuff" estimate.


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Registered: March 09, 2006Reply With QuoteReport This Post



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Hi Murphy,
quote:
Originally posted by Murphy:
Here you go:
http://avogadro.chem.iastate.edu/MSDS/methanol.htm
Scroll down to section 9.. see "Vapor Pressure"

The most commonly noticeable example of vapor pressure can be seen in a common household 6 gallon plastic gas can. Put some gas in it and leave it outside on a summer day and watch how the sides bulge out. Pop off the air vent and you'll hear the hissing sound as the vapor, under pressure, escapes.
Every liquid has a vapor pressure including water.
If you put water in a sealed container and put it in the sun pressure will build up in the container.
Does that mean water has a "head pressure" too?

If you contemplate this question it will help you get a better understanding of the situation.

"If the ambient air temperature is 70F and I fill a closed-top 55 gallon drum that is at 70F with methanol that is at 70F and then seal the drum tight and maintain the temperature at 70F, will pressure build up in the drum?"






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hi Murphy,
Several years ago I did a fair bit of research and experimentation on how much methanol is lost out of an open reactor vent pipe while the reaction is running and the heat is off.
This is quite similar in many ways to that situation.

In answer to my question:
"If the ambient air temperature is 70F and I fill a closed-top 55 gallon drum that is at 70F with methanol that is at 70F and then seal the drum tight and maintain the temperature at 70F, will pressure build up in the drum?"[/QUOTE]
The answer is no, there will be no build up of pressure in the drum as long as the temperatures are maintained the same.


quote:
Methanol has a head-pressure, albeit small, and will slowly evaporate out of the drum. The speed of that evaporation is temperature dependent...
Assuming you have a pinhole opening, it would probably evaporate a coffee cup per week at 70degF.. Just an off the cuff estimation. Not a big deal.
There are other things that affect evaporation rate besides temperature.
In this case 'surface Area' is more important than temperature.
You have nominated a "Pinhole" at 70F

As we all know, as long as everything is at the same temperature there is no pressure in the drum of methanol so the only loss from the drum will be the tiny amount of methanol exposed to the atmosphere at the pinhole.
No doubt a molecule of methanol will wander out of the pin hole from time to time, but how much?
I have just finished a 4 day experiment to help answer this question.

THE EXPERIMENT
I keep a 1.25ml Dr Pepper bottle mostly filled with methanol sitting in the cupboard "just-in-case".
It was at room temperature and of course there was no pressure in the bottle.
I took an old nappy/diaper pin that was used back in the days when disposables were not all the rage, poked a pin hole in the screw on top and wiggled the pin around a bit to make sure it was a good and proper pinhole.
I made sure I could see daylight through the hole and blow through it.
I then weighed the bottle of methanol and left it sit on the table next to me.
Ambient temperature varied from around 71F to 76F
I weighed the bottle every day

At the start of day 1 the bottle of methanol weighed 897g
At the finish of day 4 the bottle of methanol weighs 897g

Total loss of methanol in 4 days due to all causes- 0g

Another question to ponder
Assuming you are not leaving your methanol drum sit in the sun, how hot is the hottest the methanol in the drum will get?

This message has been edited. Last edited by: Tilly,






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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