Vegetable Oil SVO WVO waste cooking oil as biofuel

[HoldOnTight]

At first, it looked like a reading >2%, but after 15-30 min of waiting, it indicated 2%<FFA<3> 8/3200 = .0025 or 2500 ppm.

I don't understand the FFA or ppm part. Did you do a water test of some kind?

I am waiting on starting FFA tests since I also plan to run ASTM D2709, Sandy Brae, and HPT on each sample. I am still waiting for some of the equipment to arrive.

Sun,

To answer your questions:
FFA was indicated between 2 and 3%. The PPM water content calculation is bogus, due to issues with the condensor leaking air in from the garage air rather than 100% from the tank. The question is, if the vacuum drying process, when no issues arise, provides X oz of water, it this a good representation of the total water content of the oil. If Y is the total volume of oil (in oz.)) undergoing drying then X/Y => a ppm water content can be calculated. That is what I attempted to do with 8/3200. It was a trial run anyway. I decanted this batch and I'm burning it this week along with a previously processed 30 gal.

I don't have the ability to compare these techniques against what I do in my garage. Few have this ability so someone else is going to need to run the other test methods.

Also, my plan to take measurements and process on Sunday went up in smoke when I found that I needed to travel on Sunday to attend a meeting on Monday morning.

[SunWizard]

Here is a study done by MAN engines of Germany, where they created fuel specifications for used cooking oil in MAN B&W engines.

http://www.ufop.de/downloads/MAN_GreenPower.pdf

They made a spec for acid number (TAN) less than 4 which equals 2% FFA. They did long term tests, >15,000 hours and include lots of good info like power, emissions, etc. They even tested fish oil, which had the highest FFA at ~7%.

Another report from MAN where they mention FFA many times in creating their standard for WVO in their huge, expensive engines:
http://www.ufop.de/downloads/MAN_Biofuel.pdf

Here is a report by the Fuel Injector makers (FIE) Delphi, Denso, Stanadyne, and Bosch which says:
FFA Provides an electrolyte and hastens the corrosion of zinc. Mono- & di-glyceride corrodes non ferrous metals, Filter clogging, Soaks cellulose filters, Sediments on moving parts and Injector Coking, Lacquering.
They mention separately water soluble acids that are listed under aging products. These corrode all metals, and are also detected by FFA tests.

[SunWizard]

I did testing 8 hours today. Here are the interesting results.

I tested using some VO that has been stored for 1 year in a full barrel, tightly sealed. I took my 1 gallon (sample A) from 3/4 of the way down in the barrel, and stirred it well. A year ago it was centrifuged, dewatered, and passed a HPT with no bubbles. It still passed a HPT with no bubbles.

The FFA test strips give 4.5% FFA, the same at 350F or 77F. Doing it hotter simply makes the strip respond quicker, within a few seconds. With it cold, it took about 1 minute to fully develop 50% color in the 3rd band.

Then sandy brae water tests (www.sandybrae.com) 1st I combined the 2 reagent bottles into 1, and did a test on 30ml of the reagent since I had seen others report wet reagent. It tested with 120ppm water. So each reading I will report using 10ml reagent will be corrected by -40ppm. All SB tests were run with VO at 77F so no temp. correction needed.

Surprise#1: Sample A which passes a HPT with no bubbles tested 1100 ppm water. So the HPT isn't detecting water at the levels people have thought in the past. Tested with ASTM D2709, 0 ppm. So you can't just talk about ppm unless you specify the method.

Then I dewatered sample A with vacuum distillation with a 25" automotive vac. pump in a airtight vessel on the stove at 220F for 10 minutes. My wife whined so I got back in the garage ASAP. This I call AD (sample A, dewatered) tested 560 ppm after cooled to 77F. This shows how quick heated vacuum distillation can be since it cut the dissolved water in half in 10 minutes. I did this dewatering on another batch and SB test again, got exactly the same 560 ppm results which was a surprise.

Then as a check of the accuracy of SB, HPT and ASTM, I used a standard lab method called spiked samples. I made 3 samples each 1000ml of VO: to the 1st I added 1ml water = AD+1000ppm, 2nd +5ml =AD+5000ppm, 3rd +10ml = AD+10,000ppm. I put each 1 separately in a blender on low and ran for 15 seconds to stir well.

Here is a test summary:
Sample SB HPT ASTM
A 1100 0 0
AD 560 0 0
AD+1k 1760 0 0
AD+5k 7000 fail ?
AD+10k ? scary 500

Some interesting results already, a sample AD+10,000 which = 10,560 ppm will pass the ASTM test standard for Diesel and biodiesel of 500ppm. This also means this old high FFA sample is holding almost 10,000ppm of water dissolved! Another surprise, the sample with 7000 ppm water didn't crackle in the HPT, just a lot of bubbles, maybe 200/sq. inch. The sample with 1760 ppm water also passes the HPT with no bubbles.

The ASTM test involves spinning in the lab CF for 10 minutes at 1000g, which is very cool to hear and watch since its antique, but scary (not shielded) and made my arm tired. I sort of hid behind a 1x12 board as a shield since this was my 1st time running it. This is equal to 7 days of settling. I also plan to try it with heated 160F samples which is a modified D2709 test called D1796 and is better for higher viscosity. This would put the saturated dissolved line far higher than my previous research shown in the chart in post #1.

I am also testing using carbide as a reagent in the SB unit, since the calcium hydride packets cost $2-$4 per test due to hazardous materials shipping cost, while carbide is cheap. It responds very slowly and makes much less pressure, more testing of it will be done.

I performed a mini-mistwash on sample A (since its probably the highest FFA I have on hand) to see if there were water soluble acids, if there were I could lower the FFA with a mistwash. My TDS meter on the distilled water portion shows almost no soluble acids/soaps/salts at 7 ppm, and the FFA test strip is showing the same 4.5% result after the mistwash.

I still have all these calibrated samples around if anyone has more ideas for them, or thinks of flaws in my test methods.

[SunWizard]

Here is another project I am doing with all these calibrated samples and tests, a capacitive water sensor. It only cost $50, and is giving interesting results (better than any other test I am running, and no cost per test) so I have started a thread for it here:
Homebrew capacitive water in oil meter testing

[HoldOnTight]

Sun,
Cool!

So you took a sample 3/4 from the top and then stirred up the sample, or you stirred up the barrel and then took a sample 3/4 from the top?

I think stirring the barrel first is a good approach if you want to simply get the average FFA reading.

I think sampling at 1/8, 1/4, 1/2, 3/4 from top would show if FFA's reside lower in the barrel, like water. What are your thoughts?

Do the lighter FFA's reside at the top of the barrel or because they are smaller, do they reside at the bottom? I think they would be at the bottom, as you do. It would be good to confirm. Leaving the bottom of the barrel might be all good (consider FFAs and water).

It seems like the 10k sample didn't follow the trend, oddly. Why?

[SunWizard]

So you took a sample 3/4 from the top and then stirred up the sample, or you stirred up the barrel and then took a sample 3/4 from the top?

I didn't stir the barrel since it has PHO settled on the bottom which makes a whole different set of problems. I wanted FFA from the lowest point I plan on using which is my standard for where I HPT also.

I think sampling at 1/8, 1/4, 1/2, 3/4 from top would show if FFA's reside lower in the barrel, like water. What are your thoughts?

Yes if the barrel has been settling for a while that sounds good. I am liking the FFA test, its so simple and I am really seeing the difference between old batches.

Do the lighter FFA's reside at the top of the barrel or because they are smaller, do they reside at the bottom? I think they would be at the bottom, as you do. It would be good to confirm. Leaving the bottom of the barrel might be all good (consider FFAs and water).

Yes that's how I do it.

It seems like the 10k sample didn't follow the trend, oddly. Why?

Thats a lot of water. Some probably was settling out even in my sample jars in the few minutes before the test, making the results hard to get. Also the SB unit is much less accurate in that higher range since I only use a very small VO sample unlike the 0-1500 ppm range.

[SunWizard]

Here are the results on the next batch of VO, sample B from the bottom of a 330 gallon tote, stored for 6 months, from my better restaurants. FFA=2%
Sample SB HPT ASTM
B 560 0 0
B+500 1300 fail 0

Sample B+500 failed the HPT with about 20 bubbles/sq. in
This confirms my theory that lower FFA VO holds much less water before saturated. I will try some new from the bottle VO next. This also shows the water levels detected by the HPT varies depending on FFA.

[SunWizard]

Here are the results on the next batch of VO, sample C new oil, expired date by a year. FFA<1%
Sample SB HPT
C 160 0
C+500 700 fail

The most interesting data points this provides are on the
capacitive water sensor chart here.

[SunWizard]

Since the oxidation/polymerization process which creates FFA is a chain reaction, adding bad WVO cubes in with the good ones could make the degradation speed up drastically on your otherwise good oil. Which would be OK if you planned on burning the WVO quickly (within weeks) and not storing it.

A good strategy would be to combine, then test the cubies combined only from the same restaurant since they will be somewhat consistent. That way you could flag a bad restaurant you may not want to keep. There are many places I have rejected over the years. Now I have a much more objective way to make that hard decision to say, sorry I don't want your WVO any more. I will especially FFA test any source that has too dark of color, or an off smell.

I don't have enough testing history to decide if a baseline plus random sampling for each source is enough, or that I need to test every barrel. I usually collect 55 gallon barrels at a time (sometimes 3x55 from one source) so I will do each barrel for now until I have the data to make the decision of how often to test. Data about the FFA level, and variance in the FFA from the same source, reported by others who start doing this test could help that decision for all of us.

[HoldOnTight]

Since the oxidation/polymerization process which creates FFA is a chain reaction, adding bad WVO cubes in with the good ones could make the degradation speed up drastically on your otherwise good oil. Which would be OK if you planned on burning the WVO quickly (within weeks) and not storing it.

A good strategy would be to combine, then test the cubies combined only from the same restaurant since they will be somewhat consistent. That way you could flag a bad restaurant you may not want to keep. There are many places I have rejected over the years. Now I have a much more objective way to make that hard decision to say, sorry I don't want your WVO any more. I will especially FFA test any source that has too dark of color, or an off smell.

I don't have enough testing history to decide if a baseline plus random sampling for each source is enough, or that I need to test every barrel. I usually collect 55 gallon barrels at a time (sometimes 3x55 from one source) so I will do each barrel for now until I have the data to make the decision of how often to test. Data about the FFA level, and variance in the FFA from the same source, reported by others who start doing this test could help that decision for all of us.

I agree. Having some good tools to understand the quality of the oil is as important as knowing how to process it or having a good conversion, with appropriate gauges to assess conversion performance and suitability. How do you know the FFA of your oil at the top of the drum is the same as the bottom if you don't test it? How do you know you aren't sabotaging your processing if you don't drain/toss that bottom 5 or 10%?

I had one Chinese Buffet, owner had 7 restaurants and he wanted me to take oil from all in town. The oil was so-so. (Do you like that quantitative description??? lol) I couldn't do that. I told him I would get oil closest to where I work and the one closest to my home. He agreed!

Over the next couple months, I noticed the oil got darker, the fried food at the restaurant seemed to be more rancid, consistently! So I stopped eating there and I stopped getting his "oil." End of story.

[SunWizard]

Here is a summary of my results comparing the different water tests:
With only the HPT we have been mostly in the dark about what's really going on. My testing is showing the HPT isn't very good, and sandy brae isn't either. I like to get the WVO dry enough that no suspended or free water will form due to a cool down or a little humid air coming in through the tank vent. My goal with all this is to make it easy for testing; and the 2 tests I like best (% saturation meter + FFA) now meet that goal, being even easier than the HPT. I am putting my data into charts since they are easier to understand than all the text. The text is for the types who want to analyze and prove to themselves how its working (maybe make some charts themselves), and how I developed the ideas. Because the idea of % saturation is new.

I have found PPM is a bad measure to compare WVO, since it varies hugely depending on the FFA. It looks to me like % saturation is much more useful than PPM. I set a goal to get the % saturation below 60%. I find that 60% is easy to reach since my CF runs have all been getting below 30%.

I have found that ASTM D2709 testing isn't very useful, since it always gives me a 0 PPM result except in very high water samples, similar to the HPT. I want to know how far below 100% saturated I am dewatering to and it doesn't tell me. Here is another issue: 0 ppm by ASTM measures 1500 ppm by sandy brae on my higher FFA samples.

I don't care as much about PPM now, I am mainly reporting it as a means to compare to the tests that have measured PPM in the past. And I bought the expensive little tester so I might as well at least use the 50 test packets it came with. Its also useful to test the accuracy of the % saturation meter, which I am finding is more accurate than sandy brae.

[Idhlbly]

I am in the process of converting to a two tank SVO system (SunWizard Design) on a 96 Cummins. I have been researching for several years to see the long term effect on engines. My conclusion is that I can CF enough to get clean oil but I am concerned about FFA and polymerization.

My commute to work is short so I will not be getting up to temp during the week. I would expect to use SVO on most weekends. Because of my planned infrequent use It appears that I will have polymerization and high acid levels even with low initial levels of FFA.


This may be overkill, but should i do the following to prevent damage to the system:

AFTER EACH WEEKEND
- Turn off the heat to the SVO system (tank, filter, FPHE, ETC)
- Drain WVO and replace with diesel in SVO Tank
- Run diesel through the SVO system during the week.
BEFORE EACH WEEKEND
-Replace diesel with WVO after testing for acceptable FFA levels in the WVO.


OR??? should I not use SVO if my use is infrequent?

[SunWizard]

No need for any of that extra work. Turning off the heat is easy, so might be worth it during the week, it depends on how bad your WVO is to start with. Simply use a WVO tank that is sized so that the contents are consumed within a month and don't heat the tank too much and you can easily avoid poly. I use FFA test strips on my WVO and can easily determine how good it is and how quickly it goes bad. The reason testing is the only good way to determine whats going on is that WVO varies in properties, and rate of poly is influenced by many factors like how much it was used, storage temp and amount of air space in storage.

[John Galt]

My testing is showing the HPT isn't very good, and sandy brae isn't either.

I agree that the HPT is at best a rough go-no go qualitative test that is very much dependent on operator experience.

What problems did you experience with the SandyBrae tester?

I've been using a calibrated 'carbide manometer' with very good repeatable success. It's a good quantitative test with accurate repeatable results. I prefer it because I can use it on a variety of fuels including fuel blends.

Have you had the opportunity to compare it with your preferred method?

[SunWizard]

What problems did you experience with the SandyBrae tester?

It takes about 10 minutes for a test (the PPM number slowly keeps increasing) so is easily subject to operator error if you stop too soon, and was not very repeatable on the same sample tested again. Especially with the low PPM numbers that I typically get my WVO down to after CF. And it cost $2 per test for the reagents, compared to my capacitive meter which costs nothing per test and gives results within a few seconds.

I've been using a calibrated 'carbide manometer' with very good repeatable success. It's a good quantitative test with accurate repeatable results. I prefer it because I can use it on a variety of fuels including fuel blends.

Have you had the opportunity to compare it with your preferred method?

Yes I tried carbide and it was even slower than the sandy brae, and had the same problem that the number slowly keeps increasing over time. It also had a large variability in result depending on how finely powdered the carbide was, or which chunks of carbide I took from the bigger jar to be crushed. After the cap. meter turned out to work so quick, accurate, and repeatable I ended the series of tests with sandy brae and carbide.