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propposed method to dewater your bio-diesel. Need some input

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September 15, 2013, 12:06 PM
Samuel
propposed method to dewater your bio-diesel. Need some input
First lets take a look at Epsom salt (magnesium sulfate). Magnesium sulfate and water really loves each-other. Magnesium sulfate is only slightly soluble in methanol and isopropyl. Contrary to what some believes and what I have said before in another post, Magnesium sulfate and water likes each other so well when you mix in Magnesium sulfate with your very wet isopropyl the Magnesium sulfate will adsorb all the water it can hold and if there are still water left the water will dissolve enough Magnesium sulfate that it will separate from the isopropyl in a water layer. I just recently done a experiment and was shocked to see this. I don't know if all the water separated and will test this later. I did however had to thoroughly mix it. I am not sure if Magnesium sulfate is just poured in and settles to the bottom it will form a water layer. I will be testing this soon. The red heat (used as a gas dryer) used to be 99.99% isopropyl but that has changed. Its darker and got garbage in it that effects the titration so now I have to use rubbing alcohol for a source of isopropyl. This has 10% water which I like to remove. I think Magnesium sulfate should act the same way with methanol as it does with isopropyl. I am going to test it to make sure and plan to do a follow up post.

One sure way to remove water from your finished bio-diesel is simple to heat it so hot that the water boils out. This takes a lot of energy and there is a problem. Even though water may boil at 112F if its at the bottom of the tank you are heating the oil that's pressing down on the water puts the water under pressure. When water is under pressure it take a lot more than 112f to boil it off. I discovered this the hard way. Methanol on the other hand is far easier to remove from your bio-diesel than water. Its either on top or mixed in your bio-diesel so the pressure effect isn't isn't the same thus its far easier to flash off methanol than water.

Methanol and water tends to like each-other much more than oil and water. By heating your oil to around 140F most of the water will settle out to the bottom. Drain this off. At this point your bio-diesel will still be slightly wet. By mixing equal parts methanol to your bio-diesel nearly all of your water will be adsorbed by the methanol. Let the bio-diesel settle out and what you should have is bio-diesel with around 5% methanol. Do not use this in your engine. Some rubbers and metals not effected by bio-diesel may still be effected by methanol. You can than heat your bio-diesel to flash off the methanol. It takes less energy to flash off methanol than water. If you are already recovering you methanol from the waste glycerin than you already have you flash tank.

When your methanol becomes too wet to reuse, sodium sulfate and Magnesium sulfate can be used to dry your methanol. I prefer Magnesium sulfate over Sodium sulfate because its not temperature sensitive. Magnesium sulfate will adsorb water at a lot broader temperature range than Sodium sulfate.


Drying your methanol is very easy using Magnesium sulfate. Magnesium sulfate is capable of adsorbing a tremendous amount of water by weight and its very easy to re-dry your Magnesium sulfate. Simply heat it to 450F and its ready to be used again.

One thing I am not sure about and hoping someone can clarify. Is there any possibility that a tiny bit of Magnesium sulfate in the methanol could contaminate the Bio-diesel?? If this is the case than this method might not be such a good ideal.

I know its safe to process waste oil with Magnesium sulfate dried methanol as long as the bio-diesel is washed with water. But is it safe to dry Bio-diesel using methanol that was died by magnesium sulfate? Does anyone know if there will be problem of having Magnesium sulfate contaminated bio-diesel?

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


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September 17, 2013, 10:51 PM
WesleyB
I've dried biodiesel using dried epsom salts. The epsom salts with water in it is soluble in glycerine. So, if my biodiesel has glycerine in it then the epsom salts dissolve in the glycerine that is in the biodiesel. I dried the biodiesel on the scale of about 4-8 ounces of biodiesel. It works on a small laboratory scale but it might be expensive on the back yard brewers scale. I'll explain some if you're really interested. Do you know what a mole is? Thanks
September 18, 2013, 06:55 AM
Samuel
quote:
Originally posted by WesleyB:
It works on a small laboratory scale but it might be expensive on the back yard brewers scale. I'll explain some if you're really interested. Do you know what a mole is? Thanks



yes it would be expensive if it couldn't be recycled
I need to be able to recycle the Epson salt that way its not expensive.
yea I know a little bit about a mole. Go ahead and explain. I am always up to hearing a good ideal.


I was also contemplating pumping air through Epson salt than bubble this really dry air through hot biodiesel to remove the moister.


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September 18, 2013, 08:57 AM
WesleyB
120.366 grams of anhydrous magnesium sulfate absorbs about 126 grams of water to form the heptahydrate. Heating the heptahydrate to above 392 degrees farenheit drives off the water and makes the anhydrous form of magnesium sulfate again. Anhydrous magnesium sulfate is also called a desiccant, or drying agent. I don't know how fast it absorbs water from wet biodiesel. I think that's pretty good about how you dried, to some extent, isopropyl alcohol with anhydrous magnesium sulfate. Reusing the magnesium sulfate after drying biodiesel may be a problem. I just discarded the small amount I used to dry biodiesel. The magnesium sulfate had biodiesel all though it. I didn't put that mess in the oven I cook food in.
September 18, 2013, 04:17 PM
Jon Heron
Why on earth would you waste methanol, the most costly part of bio production, in a roundabout way to try and dry biodiesel that has no reason to be wet in the first place?
It makes no sense, there is no longer any reason to add water to the biodiesel, never mind all of the readily available tested and true methods to dry the fuel, if for some reason you dont feel like using chips...
And then there is the uncertainty of what the salt is putting in the fuel, its crazy.
This method would make no sense whatsoever to anyone producing batches larger then a few litres at a time, I dont even see any sense in using it for 500ml batches, that is if in fact it even works at all...
Cheers,
Jon


___________________________

Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
September 18, 2013, 05:13 PM
Ryan P.
Hey, everyone has different needs in their fuel production. And he's not wasting it; he says he can probably pull all the water back out of the methanol. Try not to be judgmental; offer honest comments and if its not a good idea, that will become apparent without having to bluntly say, "Hey, that's a good idea..."

You know...unless its a REALLY bad idea...like heating your WVO in a 50gal drum over an open flame... Eek
September 18, 2013, 05:59 PM
taralec
quote:
Originally posted by Ryan P.:


You know...unless its a REALLY bad idea...like heating your WVO in a 50gal drum over an open flame... Eek


Aww thats blown a big hole in my new method,was going to have the flames licking up the drum sides to stop water recondensing-also thinking about doing it indoors to recapture the heat Big Grin Big Grin
September 18, 2013, 10:56 PM
john galt
It's simpler and easier to use water absorbing polymers.
http://en.wikipedia.org/wiki/Superabsorbent_polymer



September 19, 2013, 11:32 AM
Samuel
quote:
Originally posted by john galt:
It's simpler and easier to use water absorbing polymers.
http://en.wikipedia.org/wiki/Superabsorbent_polymer


That is the way to go. I would have to find a water absorbing polymers that isn't effect by methanol and biodiesel chemicals and doesn't have a limited life cycle. Polymers are also expensive compared to Epson Salt
and some of them gets poisoned after a certain amount of use. If I can find one that can be used infinitely , easy to recycled and the initial cost isn't too high I would definitely use it.
I like epsonsalt because its so easy to recycle and can be use infinite number of times.


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September 19, 2013, 11:58 AM
Samuel
quote:
Originally posted by WesleyB:
120.366 grams of anhydrous magnesium sulfate absorbs about 126 grams of water. I don't know how fast it absorbs water from wet biodiesel.


yes that is very good. Magnesium sulfate is one of the dryers that has a very fast absorption rate when used to drying alcohols. How fast moister can travel through biodiesel to come into contact with the Magnesium sulfate may not be the same as with alcohols.



[QUOTE
Reusing the magnesium sulfate after drying biodiesel may be a problem. The magnesium sulfate had biodiesel all though it. I didn't put that mess in the oven I cook food in.[/QUOTE]


Assume the magnesium sulfate didnt contaminate the biodiesel I think it can be recycled by washing with solvents to help separate the biodiesel from magnesium sulfate. I will have to test this though.

If the methanol acts the same way as isopropyl than I can put in a small amount of magnesium sulfate, just enough for the water to dissolve. The water should settle out in a layer because its no longer mersible to the methanol after being saturated with magnesium sulfate. The methanol on the top layer should have very little water if any and should only take a very small amount of magnesium sulfate to finish trying it. I am going to test this on the weekend and post my results.


Biodiesel for cleaner air and fuel independence!
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September 19, 2013, 12:09 PM
Samuel
quote:
Originally posted by Samuel:
quote:
Originally posted by WesleyB:
120.366 grams of anhydrous magnesium sulfate absorbs about 126 grams of water. I don't know how fast it absorbs water from wet biodiesel.

yes that is very good. Magnesium sulfate is one of the dryers that has a very fast absorption rate when used to dry alcohols. How fast moister can travel through biodiesel to come into contact with the Magnesium sulfate may not be the same as with alcohols.




quote:

Reusing the magnesium sulfate after drying biodiesel may be a problem. The magnesium sulfate had biodiesel all though it. I didn't put that mess in the oven I cook food in.



Assume the magnesium sulfate didnt contaminate the biodiesel I think it can be recycled by washing with solvents to help separate the biodiesel from magnesium sulfate. I will have to test this though.

If the methanol acts the same way as isopropyl than I can put in a small amount of magnesium sulfate, just enough for the water to dissolve. The water should settle out in a layer because its no longer mersible to the methanol after being saturated with magnesium sulfate. The methanol on the top layer should have very little water if any and should only take a very small amount of magnesium sulfate to finish trying it. I am going to test this on the weekend and post my results.



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September 19, 2013, 12:12 PM
Samuel
quote:
Originally posted by WesleyB:
120.366 grams of anhydrous magnesium sulfate absorbs about 126 grams of water. I don't know how fast it absorbs water from wet biodiesel.


yes that is very good. Magnesium sulfate is one of the dryers that has a very fast absorption rate when used to dry alcohols. How fast moister can travel through biodiesel to come into contact with the Magnesium sulfate may not be the same as with alcohols



quote:

Reusing the magnesium sulfate after drying biodiesel may be a problem. The magnesium sulfate had biodiesel all though it. I didn't put that mess in the oven I cook food in.



Assume the magnesium sulfate didnt contaminate the biodiesel I think it can be recycled by washing with solvents to help separate the biodiesel from magnesium sulfate. I will have to test this though.

If the methanol acts the same way as isopropyl than I can put in a small amount of magnesium sulfate, just enough for the water to dissolve. The water should settle out in a layer because its no longer mersible to the methanol after being saturated with magnesium sulfate. The methanol on the top layer should have very little water and should only take a very small amount of magnesium sulfate to finish trying it. I am going to test this on the weekend and post my results.


Biodiesel for cleaner air and fuel independence!
(502) 272-6333
September 19, 2013, 12:29 PM
Samuel
quote:
Originally posted by Jon Heron:
Why on earth would you waste methanol, the most costly part of bio production, in a roundabout way to try and dry biodiesel that has no reason to be wet in the first place?
Jon


You must of read my post wrong. I don't waste methanol. I dry it and reuse it.

I wash my fuel in water with extreme agitation. Its wet and it needs to be dry. I wont use wood chips for a number of reasons.

quote:

It makes no sense, there is no longer any reason to add water to the biodiesel, never mind all of the readily available tested and true methods to dry the fuel, if for some reason you dont feel like using chips...


Washing with water is cheap and effective as long as I find a good way to dry the fuel. Maybe you have a suggestion on drying fuel.


quote:

And then there is the uncertainty of what the salt is putting in the fuel, its crazy.


There is no uncertainty as I will test it before using in production.


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September 19, 2013, 02:09 PM
john galt
quote:
That is the way to go. I would have to find a water absorbing polymers that isn't effect by methanol and biodiesel chemicals and doesn't have a limited life cycle... If I can find one that can be used infinitely , easy to recycled and the initial cost isn't too high I would definitely use it.


Yes, the Quik'n'Dri I've been using for years meets that criteria.
http://biodiesel.coorga.com/quik.html



September 19, 2013, 04:10 PM
Jon Heron
quote:
Originally posted by Ryan P.:
Hey, everyone has different needs in their fuel production. And he's not wasting it; he says he can probably pull all the water back out of the methanol. Try not to be judgmental; offer honest comments and if its not a good idea, that will become apparent without having to bluntly say, "Hey, that's a good idea..."

You know...unless its a REALLY bad idea...like heating your WVO in a 50gal drum over an open flame... Eek

Ryan, Those are my honest comments, take em or leave em...
Cheers,
Jon


___________________________

Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
September 19, 2013, 04:20 PM
Jon Heron
quote:
Originally posted by Samuel:
quote:
Originally posted by Jon Heron:
Why on earth would you waste methanol, the most costly part of bio production, in a roundabout way to try and dry biodiesel that has no reason to be wet in the first place?
Jon


You must of read my post wrong. I don't waste methanol. I dry it and reuse it.
You are wasting the methanol you are mixing into the biodiesel that wont settle out, You know, the part where you mention "flashing off" above. That will be about 4~5% by volume IIRC.
I wash my fuel in water with extreme agitation. Its wet and it needs to be dry. I wont use wood chips for a number of reasons.
What could those reasons be? They must be substantial judging by the idea your proposing here.
quote:

It makes no sense, there is no longer any reason to add water to the biodiesel, never mind all of the readily available tested and true methods to dry the fuel, if for some reason you dont feel like using chips...


Washing with water is cheap and effective as long as I find a good way to dry the fuel. Maybe you have a suggestion on drying fuel.
Absolutely, dont add any water in the first place, saves a HUGE amount of energy, time and more importantly, WATER. If one insists on water washing then the most standard and effective drying method is spray drying with heat and lots of air circulation. No need for methanol or salt. You could also use the polymer that galt mentioned though that would not be practical for water washed fuel unless your making mini batches...

quote:

And then there is the uncertainty of what the salt is putting in the fuel, its crazy.


There is no uncertainty as I will test it before using in production.

How, exactly, will you test for salt in the bio?
Cheers,
Jon


___________________________

Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
September 19, 2013, 08:50 PM
Samuel
I don't flash the methanol off in the air. I put it through a condenser. Maybe I used the wrong wording.

I don't use wood chips because.

1. I don't have any.
2. It would be another item to dispose of once it become dirty.
3. There are no way to tell when one would need to replace the chips so some of the bio might not get filtered as good as the rest.
4. The filter time is slow unless I build a larger filter apparatus and than this mean more to dispose of.
5. Woodchips themselves have small particles. Some of this will get in the biodiesel. No way am going to introduce any more particles.
6. I have not seen enough that has convinced me there isn't other unknown problems.
Its a good way to get bacteria in your biodiesel which can effect how long the biodiesel can be stored.
7. It will pick up small amounts chemicals from the wood-chips. This may also effect storage.
8. I have seen no documented test that shows it even does a good job. people showing before and after pictures of their filtered biodiesel isn't enough proof for me.


Generally biodiesel should not be stored longer than 6 months but a lot of people including myself store our biodiesel much longer.



How, exactly, will you test for salt in the bio?

There are probably several ways to test for this. I need to do more research. Epson Salt is heavier than oil so a weight test should do the job. 200ML dried oil is weighed and recorded. Epson Salt is put in 300ML of dried oil and stirred. This is allowed to set for several days. The top 200ml Oil is removed and weighed. With my good scales I should be able to detect an 100th of a percent.


Biodiesel for cleaner air and fuel independence!
(502) 272-6333
September 20, 2013, 10:03 AM
Samuel
quote:
Originally posted by john galt:
It's simpler and easier to use water absorbing polymers.
http://en.wikipedia.org/wiki/Superabsorbent_polymer



John
One question I have, How strong of bound does polymers form with water. Even though it might be capably of adsorbing water 500 times its weight it would be useless if doesn't have a stronger bound for water than the chemical being dried.

Say for example; one wanted to dry sulfuric acid using polymers. Assuming the sulfuric doesn't react to badly with the polymer there is a good chance the sulfuric acid would pull the water out of the polymers instead of the other way around. This is because sulfuric acid really likes water and forms a very strong bond with water and it really quick to adsorb water. In chemistry there is word for this but I don't remember what it is. Ethanol above 98% purity also has a strong bond for water.

There several important factors that must be examined when considering what to use for a drying agent. I will list 8 of them.

1. Compatibility; It's chemical reaction and solubility to the chemical being dried.
2. Temperature; The range of temperature it adsorbs water.
4. Bound; The bound for water must be stronger than the chemical being dried.
5. Cost; How many times and how easy it can be recycled.
6. Adsorption; Amount of water can be adsorbed per gram of drying agent.
7. Speed; How fast it adsorbs water.
8. Separation; What method is required to separate the drying agent. Ease of separation. Example; Granules is sometimes preferred over powder because it settles quicker and easier to filter.


For methanol and biodiesel drying, I wonder if there are any good water absorbing polymers that is suitable in all 8 categories?


Biodiesel for cleaner air and fuel independence!
(502) 272-6333
September 20, 2013, 01:17 PM
john galt
quote:
For methanol and biodiesel drying, I wonder if there are any good water absorbing polymers that is suitable in all 8 categories?

yes, follow the link provided above



September 20, 2013, 04:27 PM
Jon Heron
quote:
Originally posted by Samuel:
I don't flash the methanol off in the air. I put it through a condenser. Maybe I used the wrong wording.

I don't use wood chips because.

1. I don't have any.
2. It would be another item to dispose of once it become dirty.
3. There are no way to tell when one would need to replace the chips so some of the bio might not get filtered as good as the rest.
Nonsense, of course there is! Soap titration or even a shakemup test tells you when the chips are spent. Simple and instant results.
4. The filter time is slow unless I build a larger filter apparatus and than this mean more to dispose of. Nonsense, chips are significantly faster than water washing and drying the fuel, and take a fraction of the energy. And the big plus is of course, no water in the fuel.
5. Woodchips themselves have small particles. Some of this will get in the biodiesel. No way am going to introduce any more particles. More nonsense! Would these be the imaginary particles smaller than 10u that you claim plugs up fuel injection systems? Let me get this strait, You wont risk getting particles into the fuel that would be easy to filter out, but you are willing to add water, methanol and epsom salts eh!? That's funny to me. Big Grin
6. I have not seen enough that has convinced me there isn't other unknown problems.
Its a good way to get bacteria in your biodiesel which can effect how long the biodiesel can be stored. More nonsense! Chips are a tested and true method also being used by commercial producers, commercial fuel has to pass the ASTM tests, including the oxidative stability test which of course passes.
7. It will pick up small amounts chemicals from the wood-chips. This may also effect storage.
More nonsense. Coincidentally though, what kind of chemicals are coming out of the water you use to wash? What about the epsom salts?
8. I have seen no documented test that shows it even does a good job. people showing before and after pictures of their filtered biodiesel isn't enough proof for me.
See above, its been proven to work on a commercial scale including passing all of the ASTM required testing.

Generally biodiesel should not be stored longer than 6 months but a lot of people including myself store our biodiesel much longer.



How, exactly, will you test for salt in the bio?

There are probably several ways to test for this. I need to do more research. Epson Salt is heavier than oil so a weight test should do the job. 200ML dried oil is weighed and recorded. Epson Salt is put in 300ML of dried oil and stirred. This is allowed to set for several days. The top 200ml Oil is removed and weighed. With my good scales I should be able to detect an 100th of a percent.

Sure, all of that sounds much safer, easier and efficient then all of the proven methods that have stood the test of time. I could understand going this route if it somehow was better, cheaper or more efficient than existing methods, but of course the opposite is true.
What size batches do you intend to make?
Cheers,
Jon



___________________________

Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer