I bought an old crusty 55 gallon steel drum processor, and a 55 gallon steel drum washer a couple years ago from a woman who built it in one of Girl Mark's work shops a long time ago. It's been sitting for a couple years, and today I decided to pull it out and re-familiarize myself with it, and to possibly process a 30 gallon batch tomorrow.
I have a bunch of an old bad batch of biodiesel I bought from some fellow on Craigslist. (I posted about this experience here then) It's been sitting, and a sample I pulled last week passes the 3/27 test (a few other test batches failed.) after doing a Dr. Pepper Re-process at 1 liter BD, 150ml methanol and 3grams lye.
So I find there's a couple gallons of something sloshing around in the tank, and I drain it find it has a milky and nasty look. I think it's residual rice oil, and water. So I drain it, and add about 4 gallons of BD to the tank to flush it out. It's still pretty nasty. Open up the bung on top and shine a flashlight inside, and it's pretty nasty with corrosion and gunk all over the walls of the drum.
Wash tank is pretty rusted too.
I'm beginning to think I'm going to have to take these drums to the dump, but before I do so, thought I'd check with folks here and ask what the inside of their processors look like.
Do these 55 gallon drum processors typically rust and look nasty on the insides?
Filled the processor with hot water, turned on the heater and circulated the pump for a couple hours. Also added about a cup of muriatic acid to help break things up. Lot of crud floating around.
Heater works, pump works and now I have to figure out what to do with the water.
Now having second thoughts about using this thing since I do not have easy access to a drain for the water.
Back to scratching my head.
image.jpg (41 Kb, 12 downloads) Old crusty processor
Old oil, moisture and oxygen can certainly cause steel to rust heavily.
I went ahead and finished cleaning the beast. Got as much water and nasties out that I could and hauled the funky water cube by cube till it was all gone.
I have loaded up the processor and it's circulating and heating up the oil now. Sun will help with heating soon.
I figured what the heck.
Everything has been long paid for. Time to take a leap of faith and go for it.
It sounds like you did not ensure that the inside of the processor was dry. Water can seriously interfere with your reaction.
No doubt that's perfectly true. My experience is that old biodiesel can form oxidation products that somehow react with steel causing heavy rusting. Even below the surface of the biodiesel.
This was biodiesel mixed with low sulfur diesel that had been emptied out of a vehicle after it caused the injector pump to gum up. It sat in an airtight steel drum which rusted heavily both above and below the liquid line. I ended up burning it in a house log burner.
If we get back to guldam's post, he has a processor with rust inside. Something has caused that rust. The steel has been in contact with oil.
Guldam, I would be very hesitant putting someone else's bad batch through my own vehicle, knowing the problems it can cause. May I suggest for a start that you could titrate the bad BD?
I've not titrated the bad BD but I've tested over and over, ended up 1liter bad bd to 150ml methanol, 3grams lye. I've gone to far and made gel, and not gone far enough and gotten dropout in 3/27 test. I've washed my best results, dried it and gotten crystal clear BD that passes 3/27 and shaken up test. I've confirmed my findings last weekend and today went for it!
I pulled a test sample after 2hours of processing and it passed 3/27... And an hour later we have separation.
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The way I understand it, is that VO becoming acidic (breaking down into free fatty acids) is not the same as oxidation. You may well achieve neutralization of FFA's in your batch and even convert remaining n-glycerides by transesterification, but if the oil is oxidized in the first place you will not be making simple fatty acid methyl ester and soap by-product.
Oxidation of VO occurs at the unsaturated bonds in the carbon chain, involving forms of oxygen inserting themselves at that point, creating aldehydes - downstream products including gums. This is in the middle (so to speak) of the carbon chain. Acidification occurs when the whole carbon chain is broken off where it joins onto the glyceride backbone. It's to do with electron and proton movements - not oxygen insertion - a proton of course being hydrogen. Water consists of oxygen and hydrogen, or more correctly H+ and OH-.
If the carbon chain is already converted into an aldehyde (along its length) no amount of processing is going to fix that, but it seems the chain will cleave from the glycerine backbone, and will convert into what you think is a pure methyl ester.
I am pretty sure something like that happened in my case. I used old oil, had trouble getting full conversion, and re-processed. It separated and washed. But the fact that it wasn't good BD didn't show up until it was in the fuel tank and mixed with the low sulfur diesel. Over a period of a few days my injector pump gummed up with these downstream products of oxidation and finally the engine simply would not start. The injection specialist told me the IP was a real mess. I had to clean the whole system including tank and fuel lines. The stuff I drained from the tank I put into 60 liter steel drum, with lid, and was astonished at how quickly it rusted. An expert in BD who sets up BD plants in the Pacific islands told me that bare steel somehow promotes a chain reaction. Yes, if you have good BD, you probably don't have a problem.
The moral of the story, I believe, is always use fresh WVO (now there's an oxymoron) and that is why I say that unless you know the origin of the dud batch you got off craigslist, you don't really know its chemical makeup, so proceed with caution.
The more reading I've done, the more I realize how immensely complex chemistry is, and if parameters aren't tightly controlled there is potential to go REALLY off the rails as in my case.
Just my 2 cents worth, from actual experience.
By the way, I'm nowhere near being a pale shadow of a chemist, so to someone who has a real good understanding on these subjects, what Ive written above is probably pretty clumsy.
However if you have a look at this http://en.wikipedia.org/wiki/Carbonyl you will see how similar all these substances are - Ketones, aldehydes, carboxylic acids, esters. Maybe when I referred to aldehydes above I actually meant ketones. But if you notice that the difference between a carboxylic acid (read fatty acid) and an aldehyde is one oxygen atom, perhaps that explains where the oxygen came from to rust the steel in the drum.
Wow, that's all very great information.
To further clarify:
I got this processor over two years ago and have not used it. When I picked it up it was full of rice oil. We drained all of that into totes, and I put it away in the garage, and then moved it outside and covered it a tarp, and it's sat there since.
I looked in the processor, and it had a two inch thick bit of sludge in the bottom and the side have all sorts of crusty stuff, and rust. It's more of a sitting around deal I think.
The washer is just plain rusty. I'm thinking a rinse, let it dry and then break loose all the flaky rust, and then coat the inside with an acid base iron / steel prep for painting. It' will turn the rust into a black oxide. Rinse again, and then pump the biodiesel over and wash it.
I will filter the BD after drying and then run it through a PVC column with hardwood shavings. And then through a 1micron filter. I've done this with test batches and it makes for crystal clear BD that passes 3/27 and shake em up test.
All that other chemical stuff makes me itchy. But before I run the BD through my truck I know a commercial BD processor who will test it for me.
It will likely be easier to replace the steel drum.
I have been using the processor as is. After running three 30-35 gallon batches through it, all the crusty stuff is slowly sloughing off, and the biodiesel I am getting has passed 3/27, shakem up test, and is drying quite nicely. I have run finished biodiesel through a 6' PVC column of hardwood shavings, done a final 1 micron filtration, and my Dodge surrounding a Cummins is happy as can be.
Thanks all for the feedback and kind advice.
I have another batch separating, and there is much joy!
Im no expert, since im fairly new myself at this biodiesel business... and i know a few months have passed since the last post, which would make my advise obsolete (if indeed what i propose is good advice... but, i figure if you just keep making biodiesel, the biodiesel itself will clean the drum for you. It is preached all over that, when you switch to bio, you'll need to replace your car's filter within (say) 1000miles, since bio cleans your tank and takes with it (through the filter) all the gunk left there from PetroDiesel over the years.... Is my assumption correct regarding this? will making bio eventually clean his drum? Let me know-i am here to learn
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