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Best Method to dewater >1.4% batch after AE

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http://biodiesel.infopop.cc/eve/forums/a/tpc/f/629605551/m/2417031183

October 30, 2016, 02:26 PM
westsidebio
Best Method to dewater >1.4% batch after AE
Any idea on the best and safest way to dewater oil for transesterification after AE made the water jump to >1.4%?

Using a BioPro 190 setup, I obtained some grease which titrated to 8ml and 0.14% water (using Sandy Brae) after pretreatment. Then after centrifuging, measured the water at just <0.08% water.

For AE, using the BioPro 190 after having heated the 50 gallons to 130F, I added 4 gallons of methanol and 140ml of Sulfuric Acid, and mixed for 30 minutes.

24 hours later, titrating from the top of the BioPro exceeded 0.15%. After draining all the liquid back to BioPro fill line, it titrated past 1.4% water.

Graydon mentioned it would not be a good idea to run it through the centrifuge given the methanol. As such, other than heat & settling, is there another way to dry this oil? As per Norm's presentation if I understood correctly, I need to keep the heat on until T to not let t shoot up again.
October 30, 2016, 04:19 PM
Biotom
sulfuric acid being a water mop should allow most of the water created during the reaction to be drained off in the junk after settling. Starting water plus created water is what causes the ae process to stop. How accurate is the sandy brae when there is methanol and sulfuric acid in the mix? I have and hate the sandy brae.


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
October 30, 2016, 07:34 PM
westsidebio
Thank you! Interesting insight on sandy brae accuracy.
I will run a small test batch and see what happens with the 3/27 test.
October 31, 2016, 04:42 AM
Dgs
Forget about the 20 mins when using s/b to test for water in bio or wvo.

The instructions do say about 20 mins or when the pressure stops rising, in the case of oil/bio 12 hours is better!

Only then will it read very similar to K/F
October 31, 2016, 06:53 AM
Tilly
Sandy Brae and Karl Fischer measure two different things.
They should not read the same.






October 31, 2016, 11:18 AM
Dgs
quote:
Originally posted by Tilly:
Sandy Brae and Karl Fischer measure two different things.
They should not read the same.


please explain.
October 31, 2016, 01:27 PM
Tilly
Hi Dgs,

quote:
Originally posted by Dgs:
please explain.
As per Graydon Blair's post to this forum on 1-22-2008;
"Also, it should be noted that the Karl Fisher test will detect both Bound and Free water. The Sandy Brae Tester only detects Free water."

http://www.biodieseldiscussion...owthread.php?t=22779






October 31, 2016, 02:16 PM
Dgs
I thought that is what you would say, Tilly.

There have been other discussions since then. One where Graydon contacted the S/B people and they did confirm that their meter would detect dissolved water.

I can assure you that the s/b does detect dissolved water if the test is left long enough and that the readings are very similar to the K/F

Why can I be so sure---- because I have both types of instrument.
October 31, 2016, 02:19 PM
Tilly
Hi Dgs,

quote:
Originally posted by Dgs:
I thought that is what you would say, Tilly.

There have been other discussions since then. One where Graydon contacted the S/B people and they did confirm that their meter would detect dissolved water.
I did not say dissolved water.

From Sandy Brae website-
"A. The water must be in the form of free molecules or droplets and not be chemically or physically bound."


"Not All Water Is Equal
https://www.google.com.au/sear...+test+bound+and+free
Water in a system may be thought of as present in three
general forms: bulk or “free”, absorbed, and “bound” or
monolayer water. Bulk or “free” water has the same
energy and properties as pure water. Absorbed water is
held less tightly, but still has reduced energy and
different properties than pure water. “Bound” water has
reduced energy as the result of direct physical binding of
water to the matrix by hydrogen or ionic bonding. In
reality, water molecules readily move between each of
the forms and it is impossible to quantify the amount of
water in any one form. Rather, the overall energy status
of water is determined by the relative contributions of
each of these water layers. A reduction in the energy of
the water, (i.e. lower water activity), results in less
available water for influencing biological and chemical
reactions. Moisture content analysis provides the total
amount of water, but does not differentiate the type of
water.

Karl Fischer titrations are effective at quantifying even
the tightly “bound”, and are often considered a better
moisture analysis method than loss on drying. In fact,
this extra water that is measured using Karl Fischer is
often referred to as the “bound” water. Although a Karl
Fischer analysis may provide a more complete
determination of total water content, it still only provides
the amount of water and not the energy status of the
water. Water activity measures the energy or
“availability” of water and is not dependent on the
amount of water, but the relative contributions of each
type of water. Consequently, water activity provides
better correlations to biological and chemical reaction
rates than Karl Fischer analysis.

What is Water Activity?
Water activity describes the thermodynamic energy
status of the water in a system. Though not scientifically
correct, it may help to picture water activity as the
amount of “available” water in a system. It is not
determined by how much water is present in a product,
but is a comparison of how much the water in the
product resembles and behaves like pure water. Water
activity values range from 0 (bone dry) to 1.0 (pure
water). As water activity decreases, the water in a
product decreases in energy, is less “available” as a
solvent, for microbial growth, chemical reactivity, or for
moisture migration. For example, water in a product that
has a water activity of 0.80 has enough energy to support
mold growth while the water in a product with a water
activity less than 0.60 cannot support the growth of any
microorganism. Water also becomes more mobile as
water activity increases, which influences molecular
mobility as well as chemical and enzymatic reaction
rates.
More scientifically, water activity is defined as the vapor
pressure of water (p) over a sample divided by the vapor
pressure of pure water (po) at a given temperature. By
measuring this vapor pressure relative to the vapor
pressure over pure water at the same temperature, it is
possible to determine the energy of water in the sample.
This is reasonable since water that is associated
chemically or physically in a sample has lower energy
and will not readily move into the vapor phase, thereby
decreasing the vapor pressure above the sample."







October 31, 2016, 02:24 PM
Tilly
Hi Dgs,
.........

quote:
Originally posted by Dgs:
I can assure you that the s/b does detect dissolved water if the test is left long enough and that the readings are very similar to the K/F

Why can I be so sure---- because I have both types of instrument.
So your position is that if you modify the procedure and do not follow the instructions for the Sandy Brae apparatus, you have been able to get the Sandy Brae test to read similar the the Karl Fischer.

Is your modification of the operating instructions for the Sandy Brae test reliable according to the people at Sandy Brae?






October 31, 2016, 03:47 PM
Dgs
Re your last statement it is reliable when compared to the k/f

The hypothesis you indicate re the reactions with the S/B suggest an intelligent reagent--- it can differentiate between water molecules that are physically bonded and those that are free--------CLEVER!!!
October 31, 2016, 06:01 PM
Tilly
Hi Dgs,

quote:
Originally posted by Dgs:
Re your last statement it is reliable when compared to the k/f
So you claim- however you make the proviso that instead of waiting 20 minutes to read the results as per the instructions, you need to wait around 12 hours to read the results.

Please describe the test series you performed and the results obtained that shows this procedure you recommend does give an accurate reading and that the Sandy Brae Laboratories instructions are wrong.


quote:
The hypothesis you indicate re the reactions with the S/B suggest an intelligent reagent--- it can differentiate between water molecules that are physically bonded and those that are free--------CLEVER!!!
The situation is more likely to be that you do not understand the chemistry involved.

After all, it is the people at Sandy Brae Laboratories who specifically warn in their instructions In Bold black Letters-
"A. The water must be in the form of free molecules or droplets and not be chemically or physically bound."







October 31, 2016, 07:55 PM
Biotom
quote:
After all, it is the people at Sandy Brae Laboratories who specifically warn in their instructions In Bold black Letters- "A. The water must be in the form of free molecules or droplets and not be chemically or physically bound."


the simple fact is that if you leave the sandy brae sit over night the pressure goes up that means that the regent is still reacting with water. how can you stop the test at 20 minutes if the regent is still producing gas. this tester rates junk status IMO. Or should we just blindly follow the instructions and fuch the total pressure rise over time?


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
October 31, 2016, 08:18 PM
john galt
...and how many angels can dance on the head of a pin is another pedantic argument of no consequence to reality.

The SB and carbide-manometer test for the kinds of water that cause 99% of the 'wet biodiesel' fuel problems.
People who dry their fuel to <250ppm indicated moisture won't have fuel problems relating to water unless it's introduced after testing, such as condensation of atmospheric moisture in the fuel tank.



November 01, 2016, 04:55 AM
Dgs
Biotom and john galt, yes I agree with you both.

Tilly, put your money where your mouth is. Buy a Sandy Brae, do some testing for yourself, then you will realise I am correct.
November 01, 2016, 07:18 AM
Tilly
Hi Dgs,

quote:
Originally posted by Dgs:
Tilly, put your money where your mouth is. Buy a Sandy Brae, do some testing for yourself, then you will realise I am correct.
I am waiting for you to put your test procedure and results where your mouth is.
Just describe the test series you performed and the results achieved that showed the Sandy Brae test will accurately measure Bound" water if you let it sit 12 hours

I am sure you have not performed any meaningful test series to back up your claim.






November 02, 2016, 06:02 PM
Tilly
Hi Dgs,
I see you have deleted your offer to post all the tests you claimed to have performed.
Why am I not surprised Wink






November 02, 2016, 06:43 PM
Dgs
No point in posting my tests Tilly, you would only find a reason why you didn't like the results.

Far better is this post by Graydon, look at the last paragraph.


posted October 02, 2015 04:13 PM Hide Post
Cool! You found the old research on it!

Short Answer:
- I don't know for sure on the Sandy Brae test yet. I wasn't able to get in touch with Bob today.
- If Karl Fisher and Sandy Brae get the same results, then Sandy Brae is able to detect Dissolved and Free Water.
- If Sandy Brae results are significantly less than Karl Fisher on the same samples, then we can theorize that the Sandy Brae test isn't able to detect dissolved & bound water like Karl Fisher can

I also called Gorge Analytical to refresh my memory on the ASTM Standard for water in Biodiesel.
The test ASTM calls for is ASTM D2709 - Water & Sediment
- It uses a special centrifuge with special centrifuge tubes that "spins" the sample for a specified time to force settling of the water out of the sample. The test is ONLY looking for water that can settle out of Biodiesel, or, Free Water.
- The purpose of the test is to detect water & sediment that could settle out of Biodiesel in storage or in your fuel tank and thereby cause water related problems in the vehicle or storage tank.
- The test DOES NOT look for bound or dissolved water


If Sandy Brae and ASTM match, then Sandy Brae is only detecting Free Water
If ASTM is significantly less than Sandy Brae, Sandy Brae is detecting more than just free water
If Sandy Brae is less than Karl Fisher but more than ASTM, then it's somewhere in between

What exactly? Not sure. I need to visit w/ Bob at Sandy Brae to discuss it more with him.

I remember his saying years back that there are situations where Sandy Brae can't detect water in the solution, but exactly what that is, I don't remember.

Now, for the REAL answer to all of this.
Free water is really all we care about. Bound water/dissolved water really doesn't mean squat as far as using Biodiesel goes. Why? Because it stays bound/suspended in the Biodiesel and doesn't do any harm.

Couple caveats:
Temperature plays a role in how much water Biodiesel can "suspend" or dissolve.
The hotter it is, the more water it can dissolve (think salt in water, water has a higher saturation level when it's hotter--same with Biodiesel).

Anyway, that's what I have so far. I have a note to call Bob on Monday & follow up.

In the past, the Sandy Brae was tested multiple times by multiple people against the Karl Fisher and found to report nearly identical results to what a Karl Fisher showed. Which may lead us to theorize that the Sandy Brae can indeed measure bound water in Biodiesel.

Good stuff!
-Graydon
November 02, 2016, 09:57 PM
Tilly
Hi Dgs,

quote:
Originally posted by Dgs:
No point in posting my tests Tilly, you would only find a reason why you didn't like the results
No, really, I would like to see how you designed the tests, what the controls were and your results.
You were the one making the claim that it takes 12 hours for the Sandy Brae test to achieve the same results as the Karl Fischer test.


quote:
Far better is this post by Graydon, look at the last paragraph...
Yes, well, I take things Graydon says with more than a pinch of salt too.

I can not imagine that all the Sandy Brae tests Graydon speaks of that were "tested multiple times by multiple people against the Karl Fisher and found to report nearly identical results" actually left the Sqandy Brae test run for 12 hours before reading the results.

I can show you a test result I found on line that shows the Sandy Brae and the Karl fischer test do not both achieve the same test results.






November 03, 2016, 09:56 AM
Dgs
So you take things that Graydon says with more than a pinch of salt, yet choose to not believe his last paragraph.