First batch = not so successful. Advice?

[Optimus Prime Junior Member Find all posts View Profile Close Optimus Prime]

I was pretty excited about brewing up my first batch of biodiesel, but things seem to have gone awry.

I'm using the tried-and-true "Appleseed" processor, made from a ~200L hot water heater.

I obtained 2X~20L cans of WVO from a fish-and-chips shop. I transferred these into a 200L drum to settle. Since the oil was solid at ambient temperature, I heated it in the settling drum to transfer it to the processor.

I did two separate titrations of the oil and got an average titration of 5.3mL. Using an on-line calculator, this translated to 309 grams of NaOH in 6.6 litres of methanol added to 30L of oil.

I heated the oil within the processor to the point where the water started boiling off, then let it cool slightly before adding the methoxide.

I let the circulation pump do its thing for several hours, then turned the heat off.

The next day, I tried to see what the result was. Whatever it was, it wasn't flowing at ambient temperature, so I turned the heater back on. When things were warm, I started draining from the bottom of the processor, and what I got looked neither like glycerine nor like soap. Instead, I got a somewhat reddish and rather strong-smelling (I've read someone else's apt description - like cat vomit) liquid.

The only thing I can figure that I did wrong quantitatively was to misestimate the quantity of oil I had to begin with (I devised a dipstick measuring method to measure the collated quantity in the pre-settling drum).

Is this batch salvageable, or should I toss everything and start over?

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: First batch = not so successful. Advice?

If you had water boiling from the oil, it was WAAAAY too wet to make into biodiesel.
Search this forum for "Hot Pan Test" (HPT).

Water cannot settle from solid oil.
You need to drain off the water before letting it cool off.
You then need to dry the oil while it is still liquid and you need to test for water using the HPT before you try to process it into biodiesel.

It might be best to remove that failed batch from the water heater (it was dry inside, wasn't it?) and start by making small batches of biodiesel in 2 litre cool drink bottles until you can make it reliably in small batches..


Keep at it, you can do it.

Regards,
Tony

[Optimus Prime Junior Member Find all posts View Profile Close Optimus Prime]

Re: First batch = not so successful. Advice?

If you had water boiling from the oil, it was WAAAAY too wet to make into biodiesel.
Search this forum for "Hot Pan Test" (HPT).

Water cannot settle from solid oil.
You need to drain off the water before letting it cool off.
You then need to dry the oil while it is still liquid and you need to test for water using the HPT before you try to process it into biodiesel.

It might be best to remove that failed batch from the water heater (it was dry inside, wasn't it?) and start by making small batches of biodiesel in 2 litre cool drink bottles until you can make it reliably in small batches..


Keep at it, you can do it.

Regards,
Tony

Hmm. How long do you figure it would take to settle the water out of hot oil, and realistically how thick is the water layer going to be once it does settle?

[Peda Senior Member Find all posts View Profile Close Peda]

Re: First batch = not so successful. Advice?

As Tony said water is a problem, apart from that everything seems right up to this point..

"I heated the oil within the processor to the point where the water started boiling off, then let it cool slightly before adding the methoxide.
I let the circulation pump do its thing for several hours, then turned the heat off."

Methanol boils at about 64C so unless you had let the oil cool down to about 52C from boiling off the water, you might have lost some of the methanol. Do you know what the oil temperature was when you added the methoxide? Also when using NaOh you need to drain the glycerol whilst it is still very warm else it will go solid in your tank as you experienced. I have started using NaOh after using KOh for years and it makes good bio as long as you are aware of the glycerine going solid when cool. I make 90 ltrs at a time in an Applseed and drain the glyc after 3 hrs of settle time and it is still hot enough to flow easily.
The temperature of the reaction is important so you need to know if your oil stays around 52C whilst reacting. I turn off the heater at 52C then add the methoxide and sometimes the temp will climb 1 or 2 degrees due to the reaction but a water heater will retain the heat and no need to turn on the element again. Also for 90 ltrs I run the pump for around 75 minutes but several hours for 30 ltrs is way too long and at what temperature? You could do a simple test of your batch by adding some to a jar and adding water and gently mixing. If it goes all white then you have made soap, if the water seperates and is white but there is a top layer of oily looking stuff, then that could be bio/unreacted oil and might be worth saving.
From your above info, it seams you are using a base of 5 gms NaOh/ltr oil + titration assuming it is almost 100% pure. If it is not pure you need to adjust the amount of NaOh to compensate. Do you know the purity of your NaOh? I was using a base of 5 but now use a base of 6 +titration and multiply by 1.1 for 90% pure and get complete conversion.
Best put this batch to the side until you respond with more info and get more feedback from others.
Regards
Peter

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: First batch = not so successful. Advice?

Hmm. How long do you figure it would take to settle the water out of hot oil, and realistically how thick is the water layer going to be once it does settle?

It depends on how much water and how much oil and how hot it is.

Keep warm for about 6 hours and see if anything has settled. Drain off any water you find. Take a sample of the oil from the bottom (wettest oil).
Do a HPT on it and see if the oil has much water in it, then decide how you plan to dry the oil if it contains water.

Regards,
Tony

[Optimus Prime Junior Member Find all posts View Profile Close Optimus Prime]

Re: First batch = not so successful. Advice?

Sorry it took me a while to get back to this.

Okay, hot pan test showed that there was no water in the oil - I could take it past 80C without any signs of of crackling.

I tried dissolving some in alcohol to run a pH test, and the stuff was much less soluble than raw vegetable oil. Even in warm alcohol with a lot of stirring, there were a lot of solid bits in there. Nonetheless, the pH came in at 8.5-8.6.

Also, the stuff has the consistency of congealed gravy at 60-66C.

My most likely explanation for all of this is that the oil was too hot when I added the methanol, so it probably boiled off quite a bit.