caustic soda

[Tony From West Oz]

Re: caustic soda

Colze15,

Welcome to the forum. How long have you been making biodiesel?

The byproduct should remain liquid whilst it is warm (>40°C I expect). The methanol is normally recovered at temperatures above this.
Once the byproduct cools down, it will solidify, so you must either ensure that the byproduct is out of your methanol recovery vessel before then, or keep it liquid by other means.

After the methanol has been removed, water could be added to the byproduct to keep it liquid. You would need to experiment with small batches to determine the solidification temperature of your byproduct and the proportion of water you would need to add to it to keep it as a liquid.

Regards,
Tony

[colze15]

Re: caustic soda

Sorry but do you know what factors with using NaOH causes it to go solid and are there ways to prevent this, Also can you still reclaim the methanol from solid glycerol, Im having trouble sourcing KOH in Thailand. Any advice??

[geewizztoo]

Re: caustic soda

As you may know, ethanol forms an azeotrope with water (about 4% water) that's why it's very difficult to get completely dry ethanol. Zeolite is used as molecular sieve to dry it.

If you're going to remove the methanol from the glycerine by distillation why not keep going and take the water out as well?

It all sounds very interesting, why not start a separte thread as this discussion is in the wrong place?

[charris]

Re: caustic soda

Hi Charris,
The short answer is no I don't know. There are many different grades of Zeolite, why don't you give one of the suppliers a call and they might send you a sample or two. I can't think of a reason why it shouldn't work. It absorbs water from ethanol and glycerol is a type of alcohol.

Quell my curiosity, why do you want to remove water from glycerine?

Well Mate,

Been thinking about making industrial hand cleaner and infusing it with orange oil.

I have been doing a few experiments to acidulate glycerine and thereby remove the fatty acids. The result as you know is glycerine+water+methanol. Fatty acids float to the top and the acid salt settles out on the bottom.

Methanol recovery should present no real problem. That leaves water, aromatics and colourants.

I think there are membrane filters that will remove aromatics and colourants. I'm looking into that. Perhaps a bed of activated charcoal might do it too, maybe.

That leaves the water. I asked Oily about his idea of using casting powder. It seems to work pretty well in removing water and soap from biodiesel. Maybe it might work with glycerine too. Dunno. He's not sure either.

Then I read about zeolites on this site. I have used soduim zeolite to remove the calcuim ion from hard water and replace it with a soduim ion but I did not know of the zeolite ability to remove water from alcohols.

That's it in a nut shell

Regards

charris

[robbiearvier]

Re: caustic soda

mr fuel pincher,
there is something wrong with either your NaOH or Methanol is should go a milky white colour when mixed... def not reddish!
cheers

[geewizztoo]

Re: caustic soda

Hi Charris,
The short answer is no I don't know. There are many different grades of Zeolite, why don't you give one of the suppliers a call and they might send you a sample or two. I can't think of a reason why it shouldn't work. It absorbs water from ethanol and glycerol is a type of alcohol.

Quell my curiosity, why do you want to remove water from glycerine?

[charris]

Re: caustic soda

Hi Geewizztoo,
Do you know if soduim or calcium zeolite will remove water from glycerine?
R
charris

[mr65fuelpincher]

Re: caustic soda

Hello ,All, I have successfully made a litr of washed bio diesel. using soybean cooking oil -fresh- with sodium hydroxide and methanol. later 2months-i tried again but when i mixed the methanol and lye it turned brown to reddish while the first batch was clear to slightly opaque. Can some one tell me if this is normal or what the problem is Thanks

[Alga]

Re: caustic soda

Thanks, I'll stick to the methanol until I understand the chemical theory before using ethanol. I'm amazed at the total lack of interest government has in BD in Tas, they just look at you dumbfounded and say, "its not relevant to our economic aims".

That sums it up very well I believe, braindead and locked into monopoly single point processing and distrubution so they can control energy.

[joe]

Re: caustic soda

Also Ethanol makes Ethyl Esters, Methenol makes Methyl esters. Both are called biodiesel.

[geewizztoo]

Re: caustic soda

Two main reasons:

1. KOH dissolves in methanol much faster than NaOH
2. The KOH glycerine by-product stays liquid, NaOH by-product solidifies. This can be a problem if left to cool in the processor.

This one is purely subjective....shoot me down if you like,
3. IMHO, the KOH seems more tolerant of poorer grade oils and SMALL quanities of water in the oil.

Alga,

Yes you can use Ethanol instead of Methanol, but I've read that it's harder to use unless it's really dry. Ethanol naturally forms an azeotrope of roughly 95% ethanol and 5% water. You need to use a molecular sieve, such as Zeolite, to remove the remaining water first.

[Robert]

Re: caustic soda

And, can anyone explain also the reasons why KOH is preferred over NaOH?

[Alga]

Re: caustic soda

Thanks everyone, learned a lot from that. Just for interest sake, could you substitute ethanol for methanol.

Thanks again
Alga

[fantom]

Re: caustic soda

hi robert,
pottasium hydroxide(koh) is freely available and is not used to make explosives. Ammoniun nitrate on the other hand mixed with diesel can.
cheers brian.

[Robert]

Re: caustic soda

You could be right geewizztoo - like I said, I'm no expert, so I appreciate people who can correct me .