In the last year there have been at least two reported explosions at commercial biodiesel plants apparently involving glycerin post-processing, and presumably sulfuric acid.
Has anyone been able to verify dangers of mixing...
Glycerin, Sulfuric Acid, Heat, Pressure, and perhaps air?
Potassium sulphate should be the salt left over, is that somehow reactive? I don't see how the glycerine and H2SO4 should react badly, anyone have any thoughts on this?
I can't see sulfuric acid and glycerol being an explosive problem.
If the acid is strong enough to oxidize the glycerol you might get acrolein but no bangs.
Heat and pressure are different problems. You might be able to get glycerol to explode at the right temp pressure and quantity of oxygen.
The only reactions I know of that could prove dangerous with glycerol are nitric acetic and oxalic acids, some of the esoteric sulfonic acids might also react. Only nitric reacts easily and goes bang.
If you can get the acetic acid to react with the glycerol to make Triacetin simply and cheaply that would be fantastic.
You can also turn glycerol into an explosive with the right kind of peroxide, I can't remember which one.
None of these reactions is likely to happen in bio production, methanol is the most likely culprit.
Methanol has about half the energy of TNT, so a kilo of methanol vapor has the same explosive energy as slightly less than a pound of TNT.
Methonal would be my guess as well, in vapor form it could easily reach near optimal stiochiometric efficiency and make quite a bang, we used to play with small bages full of acetylene and oxygen and it takes VERY LITTLE to make a very profound 'thud'
I dont know why they wouldnt just use HCl, It's cheaper, lighter, safer and cracks glyc into all 3 products.
Mixing and bringing the ph to ~5 seems to give a fine split.
1996 K2500 4x4 6.5TD
Have you tried this at all? If you have ,what strength HCl did you use? I have 36% HCl at work,but this probably needs diluting somewhat (bottle fumes when opened).How do you measure the pH-which layer,or do you just mix up until glyc is at 5 and leave it to seperate.
Sorry for all the question's - I've got some time off over xmas and this is one thing I want to try,along with Legal's excellent soap guide-Just had 3 weeks of solid rain,hard to do anything at the moment.
Well at least you will have no shortage of mud to try out your new soap on!
Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
Yeah its been so wet,trying to dry fuel has been a major pain.But this w'end temps are set to tumble,might even have some white stuff next week.So at least the humidity will drop,but my glyc will be like concrete-time to get the "dodgy heater " out.Watch out for a bright flash in the east!!!
All I know about my HCl is that it says 30% balm inhibitor. I wish someone could explain that to me.
I'd like to know if it can be used for soap titration.
It certainly does fume out of the tote lid and it will gag ya.
Pretty sure you can demeth before or after. FA can be water washed.
I ph meter the whole mix, then let it settle. Layers are both very dark.
I get my ratio in a mini batch and scale it. Like bio, it can different all the time.
It can be hot or warm, or maybe even cool.
I think if you go overboard on acid, you'll just be wasting acid and can only get so much.
I've done it a handfull of times, you just got to experiment.
I've had near 50/50 splits. Hot- 130*F
I'm not an expert, and this is all I know about the splitting process.
The FA can be esterified.
The rag layer should be protiens and salts?
1996 K2500 4x4 6.5TD
I think the reason for sulfuric is that it is stronger (over 90% pure) and you get more bang for the buck. If you could get stronger HCL it would probably work better. I am not sure it would be cheaper or safer.
I did a little experiment with it last winter using sulfuric acid. I didn't measure Ph or anything, but I added some sulfuric to methanol and then added the combination to soap/glycerine byproduct accumulated from gravity settling several batches of BD. Stirred it up in a drum over the course of several days and the ffa's separated out with biodiesel. It's pretty neat looking in a jar. You can see the ffa/bd layer on top, a salty brine next, then the glycerine layer with some salty brine under it. The glycerine is very clear and a little darker amber than the ffa/bd layer.
I did an experiment in a jar to crack the glycerine byproduct a couple of months ago. I guess I didn't add enough acid as it took several days to crack the byproduct.
You can use the acid for soap titration if you follow the rules outlined on CBT. Use the batch method. The girlmark article is a little confusing at first, but it can make sense once you understand the process. It was clear as mud to me when I first tried it. Double D has a detailed explanation of how to mix it up on this forum somewhere.
Thanks. I'll check it out after I get the blue stuff.
I'll order Norman's kit for the glass pipettes and use his solutions as controls to mix my own.
1996 K2500 4x4 6.5TD
I've searched high and low for 30% balm inhibitor and can't find anything. I'm guessing it may be 30% HCl that is used as a balm inhibitor?
Wikipedia has a chart that gives the specific gravity and boiling points of different concentrations of HCl. With an accurate scale and thermometer you may be able to verify the 30%.
The difference in strength between HCl and H2SO4 is not that different in neutralizing KOH or NaOH.
Edit: 3.08ml 36% HCl is equal in strength to 1ml 95% H2SO4. There is quite a difference I forgot to account for the second Hydrogen in the sulfuric. My Bad.This message has been edited. Last edited by: Double D,
I didn't know that, interesting
I made a mistake there Buckeye,
I edited the post to reflect the correction in equavalence.
I just split some byproduct(1L) last night using sulfuric for my Diisocyanate experiment. I haven't seen any ill effects...,yet.
Three layers are showing, FFA on top, glycerol below, and Sulfate at the bottom. I need to neutralize and dry the glycerol as much as is easily possible before continuing.
Just for interest's sake, how much acid did it take to split the glyc? What was your T for oil before making it into biodiesel? When you'll neutralize tell us how much it T at.
After neutralizing, what do you estimate the level of glycerin and other contaminates to be? Is there a way of working out simply?
Someone told me once that it was for carbon steel protection of some sort.
The stuff is great for pickling galvanized fittings and parts.
It probly is 30% strength.
1996 K2500 4x4 6.5TD
Loads of information-thanks guy's.Just shows how good this forum can be-long may it continue.
Merry xmas to one and all
30° Baumé maybe? If so, see: What is a "degree Baumé"?
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