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Question about a 'film' forming on top of my biodiesel
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I started making biodiesel recently. I haven't made it from WVO as of yet. I'm practicing with clean cooking oil first, then I plan to eventually experiment with brown grease.

Having said that, I mixed 110 mL of denatured alcohol with about 2.8g of caustic soda. Once they were mixed, I poured it into 500 mL of cooking oil. I have a magnetic stirrer but no hot plate, so I placed a hot gun on the side of the bottle. The result is an uneven distribution of heat around the container (overall, it ranged from 47 degrees Celsius on one side to 107 degrees Celsius on the other side). Nevertheless, the mixture of oil, alcohol, and caustic soda we foggy at first, but became a more transparent color after about 6.5 mins of mixing and being heated. The result is this:



Now the biodiesel looks like this:



What is that white 'film' stuff? Also, this biodiesel has been sitting and cooling overnight, but still no glycerin. Has it not separated yet or is it because I used clean cooking oil (so the glycerin is clean, but mixed)?

This message has been edited. Last edited by: brainy19,
 
Registered: September 05, 2015Reply With QuoteReport This Post
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Any chance of reducing the size of those pics?

Ethanol is too hard for a beginner, I don't know any experts either who use ethanol. Find some methanol.
 
Location: New Zealand | Registered: August 15, 2006Reply With QuoteReport This Post
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Thanks for the response. I do know there is biodiesel in there however, since it is more combustible than regular cooking oil (I tested that in my previous batches by lighting it with a blow torch).
I've never seen that white stuff however. And in all of my batches so far, I'm not sure where the glycerol is, is it mixed with the biodiesel?
 
Registered: September 05, 2015Reply With QuoteReport This Post
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Ethanol is also more combustible than regular cooking oil, and there is 110ml of it in your sample. For a start whatever is used to denature your EOH may have affected the result, and then again the EOH probably needs to be anhydrous, which you will probably not find easily. Look through the forums list, I see there is a section on using ethanol, but I cant answer any more of your questions.
 
Location: New Zealand | Registered: August 15, 2006Reply With QuoteReport This Post
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Hi brainy19,

quote:
Originally posted by brainy19:
...I'm not sure where the glycerol is, is it mixed with the biodiesel?
If there is glycerine present it will be mixed with the biodiesel.
From reading I have done, one way of "forcing" separation of the glycerine and biodiesel is to add some water and mix.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Hello Brainy; Initially making test batch quantities of biodiesel using ethanol is good. Methanol vapors are toxic. As little as 10 milliliters of methanol can cause blindness maybe death. Breathing it in is bad, it is like drinking it or worse.
I made biodiesel using ethanol. I tried to make biodiesel using 190 proof (95%) grain alcohol (ethanol). That didn't work because there was too much water present.
To make biodiesel using ethanol I used commercial grade 99.5% industrial ethanol. Using the usual catalyst quantities but an increased volume of ethanol per litre of new vegetable oil. Without finding my lab notes, I used something like 30% commercial grade anhydrous ethanol per litre of vegetable oil. That worked fine, a glycerine layer formed.
Ethyl biodiesel probably sucks water vapor out of the air more than methyl biodiesel. The word might be deliquescent for that kind of thing. For example if you put pure 200 proof alcohol out in a cup, exposed to the air, water vapor from the air moves into the alcohol in a forceful way. The pure alcohol sucks it out of the air until it becomes about 95% pure ethanol & 5% water.
Your white film in the photographs probably is your sodium hydroxide reacting to make soap because there is water in your denatured ethanol.Vegetable oil plus lye with water present makes soap, even though ethanol is also present.
Commercial grade anhydrous alcohol is expensive, I paid about $35 or so for 1/2 a litre of it. I expect your denatured ethanol has at least 5% water in it.
Water being present in 3-5% quantities probably decomposes the chemical in the mix that causes the transesterification to proceed that produces biodiesel.
Thanks
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post



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quote:
The minimal lethal dose of methanol in adults is believed to be 1mg/kg of body weight. The exact rates of morbidity and mortality from methanol intoxication are not available.
http://emedicine.medscape.com/...cle/1174890-overview


That datum relates to methanol toxicity by ingestion. Methanol vapors are less hazardous. Methanol can be safely used in a well ventilated area like a garage with the door open. Take reasonable precautions to avoid breathing vapors.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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Thanks for the input all. I do have some DW-R10 resin, so I will plan to do is split this into two batches. With one batch, I will add water to see if that forces the glycerol to separate. If it does, then I will separate the crude biodiesel from the glycerol, then filter it with DW-R10 resin. With the second bath, I will filter it with DW-R10 resin straight. I'll let you guys know what happens.
 
Registered: September 05, 2015Reply With QuoteReport This Post
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So I tried to filter the biodiesel with the DW-R10 resin. The 'crude' biodiesel was chunky and had film of what is probably soap, but it seemed to have worked. The biodiesel is MUCH clearer now! I did see some beads of what is probably water at the bottom, but nothing that distillation can't take care of Smile

Pretty exciting stuff. I'm now going to experiment with brown grease. Does anyone have any ideas on where I can get some? I've been emailing companies that service grease traps, but no luck so far :/
 
Registered: September 05, 2015Reply With QuoteReport This Post
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brainy19; I test the density of my biodiesel finished product. Without looking it up it's supposed to be something like 0.87 grams per milliliter when vegetable oil is something like 0.915 grams per milliliter. There's actually a big difference that cost nothing to test but some time and trouble. At an antique mall and estate sale I found many volumetric flasks of varying sizes. A 50 or 100 milliliter volumetric flask is a good enough size with a cheap triple beam balance to measure the mass of the volumetric flask, then weigh the mass of the flask when it's exactly full, then divide out the numbers to get the density. If you have excess alcohol in it it will be scewed to the light side. If all the excess alcohol is removed then an accurate density for the biodiesel (ethyl or methyl esters) could be obtained. Once I thought I was reacting anhydrous isopropyl alcohol with vegetable oil using potassium hydroxide as catalyst, the density of the finished water washed and dried product showed that the density of the finished product matched the density of the starting corn oil. A density test showed that isopropyl alcohol does not transesterify (react) with vegetable oil using the normal methods of making biodiesel. If you can, you might test the density of your finished product compared to the density of your starting material. Thanks
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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I just measured the density of my biodiesel and I got 0.86 g/mL. A little lower than 0.88g/mL, but it IS higher than the density of ethanol, which is 0.789 g/mL. I'm lead to believe that I have trace amounts of ethanol in my batch, but at least its not cooking oil!
 
Registered: September 05, 2015Reply With QuoteReport This Post
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I found my notes from making ethyl biodiesel from 99.5% ethanol and new corn oil using 85% potassium hydroxide as catalyst. After removing the glycerine layer I removed excess ethanol by vacuum distillation then treated with magnesium silicate to further purify the product. At that time in January 2012 I measured the density of the biodiesel product at about 0.8445 grams per millilitre. I measured the density of new corn oil at 0.913 grams per millilitre.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post



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In the last post I wrote a biodiesel density that was probably wrong. I still had the ethyl biodiesel from that synthesis in a storage bottle. I measured the density again. Mass of the 100 ml volumetric flask was 54.69 grams. Mass of the 100 ml volumetric flask plus 100 ml biodiesl was 141.78 grams. So the mass of 100 ml of the ethyl biodiesel was 87.09 grams giving a density of ethyl biodiesel from new corn oil as 0.8709 grams per millilitre.
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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I've only just now discovered this thread and I have some questions. In your photograph are there two layers? It looks like there might be two layers but sometimes images of fluids in glass jars are deceptive.
It seems to me that your statement that the product is ethyl ester because it's more flamable than the original cooking oil doesn't take into account the increased volatility and flamability of a simple mixture of cooking oil and ethanol.
If there is only one layer present then it seems to me that there are two possible outcomes. First, the cooking oil & the ethanol ethoxide mixture reacted but the glycerin is soluble in the resulting unreacted cooking oil-ethyl ester-ethanol mixture. Or there was no appreciable reaction.
However, we know that glycerin-methanol byproduct is not soluble in unreacted cooking oil- methyl ester-methanol mixtures because we routinely observe rapid and very complete separation every time we make diesel with methanol. Now methanol is a more polar solvent than ethanol and since the glycerin still separates in the normal case it is hard to understand how the ethanol-ethyl ester system would be a better solvent for the glycerin. It's possible I suppose just not so likely.
It's still not clear to me that you ethanol was in fact anhydrous. Keep in mind that ethanol is even less acid than methanol so that the equilibrium concentration of the "ethoxide" is even less than the "methoxide". The presence of any water whatsoever would inhibit the formation of the 'ethoxide" even more than the "methoxide".
I checked various formulas of denatured alcohol permitted by the US government, Title 27, chapter II, subchapter A, part 21 and none of the permitted formulas require anhydrous ethanol. In fact you apparently can use ethanol with as low as 160 proof ( 80%). The best formula shown required 185 proof which is 92.5% with at least 4% methanol added. My can of denatured alcohol solvent says it has less than 4% methanol so that suggests it has other denaturants and probably a good amount of water besides.
If you are determined to use ethanol to make biodiesel try to find some fuel ethanol used to make gasoline fuels. Fuel ethanol is essentially anhydrous but denatured with RBOB gasoline.
Be forwarned that the gasoline will very likely cause processing problems especially if you water wash.
 
Registered: March 23, 2004Reply With QuoteReport This Post
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When I made ethyl biodiesel using 99.5% commercial anhydrous ethanol, new corn oil and 85% potassium hydroxide, a lower glycerine layer did form. I don't know why brainy19's process didn't get a glycerine layer. The label of my anhydrous ethanol says "200 proof" on it. It was expensive and the chemical supplier called the Texas Department of Public Safety (the narcs) in Austin, Texas before she would sell it to me (9/11 type paranoia related to chemical purchases).
 
Location: Texas | Registered: April 27, 2011Reply With QuoteReport This Post
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