Waste Vegetable Oil produced by the kitchen

[OgreOwner]

Hello all,

I have been bitten by the bug of taking the Waste Vegetable Oil produced by the kitchen at the school where I teach Physical Science and reforming it into BioDiesel. I have spent the last two days absorbing what I can find on the net.

All the recipies use lots of alcohol, Sulfuric Acid and base. Each is commercially available to me, but since I am scrounging the WVO, I want to try to scrounge as much as I can, or purchase pure and recycle it.

I can make Alcohol using the sawdust from my wood shop and the newspaper that I currently throw out. Not sure how to make methanol, but I found a recipie for ethanol... Gotta use high concentration Sulfuric to treat the cellulose before letting the yeast at it. Need a way to regenerate the Sulfuric Acid used to treat the cellulose.

Transesterfication of the Oil:
Oil + Alcohol + catalyst = biodiesel and glycerine. I am wondering if the transesterification reaction can be catalyzed by platinum? I can easily plumb into the reactor a catalytic converter from the junkyard if it will save me some feedstocks.

Any suggestions or help would be appreciated.

Karl "Ogre" Peterson

 

[Ivan Seeking]

This seems to say it all

Methanol has been considered as a fuel, mainly in combination with gasoline. It has received less attention than ethanol, however, because it has a number of problems of its own. Its main advantage is that it can be easily manufactured from methane (the chief constituent of natural gas) as well as by pyrolysis of many organic materials. A problem with pyrolysis is that it is only economically feasible on an industrial scale, so it is not advisable to try to produce methanol from renewable resources like wood on a small (personal use) scale. In any case, high temperatures are involved, with some risk of fire; furthermore, methanol is highly toxic, so great care should be taken at all times not to ingest methanol, spill it onto exposed skin, or inhale the fumes.

Methanol can be derived from biological sources; Russia has an extensive program to make methanol from eucalyptus. [continued]

http://en.wikipedia.org/wiki/Methanol_fuel

You can use google scholar - pyrolysis+methanol - and find plenty of papers that discuss specific paths for methanol production, but I didn't see anything that looked easy. Most biodiesel sites tell you where to buy it.

 

[alotropia_entropia]

Talking about Sulfuric acid ,.. I need too a way to regenate this one that from Ether Synthesys in Lab Size someone could help me?
Thanks

 

[mrjeffy321]

I assume you have seen this,
http://www.green-trust.org/sawdust_ethanol.htm

The process involves using concentrated sulfuric acid to react the cellulose into a sugar[?] that can then be fermented with yeast and then distilled to extract the methanol.
However, I would not sure as to what chemical reaction is going on here. Why isn’t the concentrated sulfuric acid "burning"/oxidizing the cellulose? In my own personal experience, concentrated H2SO4 reacts quite nicely with cellulose containing materials, turning them into a black Carbon goo, not into a nice fermentable sugar. The H2SO4 likes to dehydrate the "water" out of the sugar (sucrose being C12H22O11, with a 2:1 ratio of H to O, like water), leaving Carbon behind.

What do you mean, "Regenerate" the sulfuric acid? If the H+ ions were lost, the acid was reacted, forming some type of Sulfate salt in the process. Why not just add more acid?

In the process described in the link above, the advocate distilling the alcohol out of the solution first, then raising the temperature and distilling off the water from the unused H2SO4.
However, even when simply boiling off the water out of Sulfuric acid, there still will be H2SO4 fumes coming out of the solution...especially when dealing with the concentrated solution. These fumes can get quite thick and are not much fun to breathe.

 

[Bystander]

(snip)However, I would not sure as to what chemical reaction is going on here. Why isn’t the concentrated sulfuric acid "burning"/oxidizing the cellulose?(snip)

Look at "acid paper process."

 

[Q_Goest]

Interesting short article in Sci Am, Sept. '06, pg 38.

In the first comprehensive analysis of the energy gains and environmental impact of both fuels, U of Minn researchers determined biodiesel to be a better choice. Ethanol from corn grain produces 25% more energy than all the energy people invested in it, whereas biodiesel from soybeans returns 93% more. Compared with fossil fuels, ethanol produces 12% fewer greenhouse gas emissions, whereas biodiesel produces 41% fewer.

... reported online July 12 via the Proceedings of the National Academy of Sciences USA.

 

[Ivan Seeking]

Also note that biodiesel from algae yields from 100 to 300X more biodiesel per acre-year than does soybean. We don't know the net energy return based on algae as yet since practical systems appear to be about two years from completion.

 

[OgreOwner]

What a difference a few days make...

K, Thanks for the replys.

I looked at a few of the Methanol synthesis things and nothing that I saw looked good for my pico-level endeavor.

Brewing Ethanol is looking more and more attractive. I wonder if the yeast would like the waste from the algae press... I saw the site that talks about the algae. I have some ideas for a pico-reactor.

To brew alcohol, you need a federal permit. It appears to be free to get and not much hassle other than some paperwork.

The sulphuric acid is used to dehydrate the cellulose and "unlock" the sugars that are in the cellulose so that the yeast can get to it to digest it. Am still looking for a Acid acts on cellulose leaving X, X back to sulphuric acid synthesis. Have found lots of sites for acid regeneration facilities, but nothing on how it is done so that I can try to build a pico plant to handle the 10 gallons of concentrated sulphuric that I think I would be using over and over again.

Since grains are a source of nourishment for the yeast, am going to go try to make friends with the day old bread store tomorrow. Stuff that gets too old to sell would be perfect for my reactor.

Tonight I procured 26 55 gallon drums. The next few days will be cleaning them out and up. 55 gallon drums, the test tube of the chemical engineer...

Now to go follow up on a few of the sites you guys suggested in your posts.

Thanks, and hopefully the above will keep this thread alive.

Karl

 

[OgreOwner]

The sulfuric acid indeed looses H+ to become the sulfate ion. Those sulfate ions represent an investment that I would love to recover and reuse. I am seeking free sources of Sulfuric without too much success. I am a nut about trying to make biodiesel where the only cost is the hardware to process the Waste Vegetable Oil and the alcohol.

Karl

 

[Bystander]

(snip)The sulphuric acid is used to dehydrate the cellulose and "unlock" the sugars that are in the cellulose so that the yeast can get to it to digest it.(snip)

Bit of advice --- take your planning period for a couple days next week and try some of the chemistry at a test tube scale --- get yourself tuned into the facts that you're using sulfuric acid as a catalyst to hydrolyze the cellulose linkages, you're using sulfuric acid to catalyze the transesterification reaction of cooking oil with whatever alcohol you choose, catalyst and reactant concentrations are going to have effects on yields and rates of reactions, yeast fermentation of aqueous sugar solutions is dependent upon pH, and a whole load of other "little" problems.