"With a resolution of 0.001% (10 PPM) water, any fluid can be tested as long as the following conditions are met:
A. The water must be in the form of free molecules or droplets and not be chemically or physically bound. B. The fluid should not attack the water test vessel components which are anodized aluminum and brass."
October 01, 2015, 07:08 PM
Both the SB and CM are adequate for testing biodiesel to measure the amounts and types of water that would be harmful in engines.
October 01, 2015, 07:19 PM
I had a long talk with Bob at Sandy Brae about this a few years back.
I'll give him a call in the morning & see if I can refresh my memory.
As I remember it though (and it's been a while, so I'll verify this tomorrow), the Sandy Brae can detect the same amount of water that a Karl Fisher can detect in organic oils. That is free water, suspended, or dissolved water.
However, there's one form of water it can't detect. That is bound water.
Long answer short, we don't see bound water in organic oils so the issue doesn't apply in how we'd use a Sandy Brae (with organic oils). It can, however, happen in tar and petroleum based oils. Basically, if the water is surrounded by the substance chemically to the point that the Calcium Hydride can't get to it (think tar), then it can't react with it and cause a reading. Biodiesel or veg oil will fully allow the calcium hydride to come in contact with the water so we get a full reading.
As for the "why is there a delay". It has to do with the thickness of the oil and how fast the reaction between Calcium Hydride (not calcium carbide) and all of the water in the oil can happen.
Kind of like a biodiesel reaction with catalyst. It doesn't happen all at once. It takes a while for it to fully react with all of the particles.
I'll clarify with Bob in the morning though & post back here.
Hi everyone, I have been following this discussion with interest.
My test for Water in the biodiesel is "bright and clear" In my 14 years of making and using biodiesel that is the standard I use to determine whether the biodiesel is "dry enough" My current car is 9.5 years and 265000km old using this standard of dryness with perfect results.
That said, I know some people want their Biodiesel to be drier and perform other tests to determine how dry it is.
There seems to be an inconsistancy in these three statements;
1. He then compared it (Sandy Brae) with a Karl Fisher Water Titrator that he had access to and found that the results were within tolerance.... 2. 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. 3. There also have been numerous individuals that have purchased this test kit and used it to test their finished Biodiesel product and then sent their Biodiesel in to be tested on the ASTM Standard and found that the measurement reported by the kit matched the results that came back from the ASTM tests...
The inconsistency seems to be that because the ASTM biodiesel test does not measure dissolved water, only free water and the Sandy Brae test apparently does measure dissolved water the ASTM test and Sandy Brae test should not have matched..
October 02, 2015, 04:48 AM
As I have stated before in this thread my sandy brae and kf metrohm kd758 results do match and they both detect free, suspended and dissolved water in biodiesel.
October 02, 2015, 05:37 AM
Hi Dgs, I know you have said that before. I am not talking about that. I am talking about the statement in the above linked to post;
"There also have been numerous individuals that have purchased this test kit" (Sandy Brae) "and used it to test their finished Biodiesel product and then sent their Biodiesel in to be tested on the ASTM Standard and found that the measurement reported by the kit" (Sandy Brae) "matched the results that came back from the ASTM tests..."
I think the Sandy Brae should not match the ASTM, apparently they do not measure the same thing.
EDIT I can not find a google link to your kf metrohm kd758 tester. Can you please provide a linkThis message has been edited. Last edited by: Tilly,
There it is. 5th down triad scientific.This message has been edited. Last edited by: Dgs,
October 02, 2015, 04:13 PM
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.
According to information on the net, the EU 14214 specs for water at 500ppm are : EU ISO 12937 The standard test for this is the Karl Fischer. From this I assume over here the standard is different in that ALL water is included in the 500ppm spec, ie free, suspended and dissolved. Here is a link, I hope it works.
Hi Dgs, Oh, I see now. You didn't know that the ASTM standard for water in biodiesel was different from the European EN Standard for water in biodiesel. As Graydon has said, in the USA the ASTM test is only for Free Water. Dissolved water does not count. I thought everyone knew that Welcome to the exciting world of biodiesel!
If you need anything else cleared up just ask.
October 03, 2015, 11:58 AM
I don't know everything Tilly, just like you not knowing how much soap there was in glycerol.
October 04, 2015, 06:59 PM
I thought everyone knew that Welcome to the exciting world of biodiesel!
If you need anything else cleared up just ask. [/QUOTE]
Tilly Tilly Tilly......my 10 yo daughter has better school yard conversation skills than this reply implies.... You manage to push away a lot of people with real input with your comments,to the detriment of this and all the other Bio forums in the world.
Pity really because you seem to be full of a lot of useful info.
I dont understand what you get out of belittling people
Until now I had no one on my ignore list
You are the first
October 04, 2015, 09:33 PM
Farmerpete-au Farmerpete-au farmerpete-au.... I am sure that if I had a 10 year old daughter she would have better school yard conversation skills too...
All the best to you, and even though I am now on your ignore list and you have not read this, I will continue to give you the same assistance I have given to you in past threads. All you have to do is ask.
PS I Welcome you to the exciting world of biodiesel too!
October 05, 2015, 01:02 PM
For what it's worth, at no charge, I expect that dissolved water amount is proportional to soap content and any free fatty acids present in the biodiesel sample being measured for water content. So, therefore a more accurate measure of water content may be enabled by a purer biodiesel product. Excess methanol in biodiesel might also be a solvent for water, since the methanol dissolves in the biodiesel.
October 05, 2015, 06:42 PM
Hi Wesley, I try to get my biodiesel as dry as possible (within reason) After water washing and drying I usually find the soap level is 10 or <10ppm and after the turbo dryer has been on 4 hours with the bio at 65degsC the water level is 100 to 120ppm, as measured by KF. I have experimented and left the dryer on for double the time and the water content was 50ppm. (totally impractical but it was just to see)
I have made a small mod to the dryer in that for the last 1 hour drying the air exiting the extraction fan is piped directly into the silica gel container, the air exiting the fan is dryer than ambient so this method is slightly more efficient.
October 06, 2015, 02:21 AM
HI Dgs. going back to the RH approach. I tried this with my last batch. In my set up I heat and dry the filtered 100mu oil with gas in a separate drum. On top of this drum is a spray nozzle built into the lid and a fan from a city golf radiator blowing dry air pulled through silica jell over the hot oil the air escapes the drum via two, 2"inch pipes on the far side of the spray forcing the air to travel over the sprayed oil. The oil is circulating via a small pump.
Any way to the point. RH of air discharge was 17% at45 deg C oil was at about 55Deg C. ambient RH was 40% @30 deg C.
On the vacuum processor I ran .6 bar vacume oil at 23 deg C. oil did not froth moisture did not condense in condenser or in slush pot. Output of vacuum pump 19% RH at 57 Deg C. The temp rise was due to the heat generated in the vacuum pump as it ran. I haven't tested for water yet.
October 06, 2015, 05:51 AM
Hi Sam, it will be interesting for you to see if there is a relationship between the R/H and the actual water level. Hopefully you will find that there is.
On my system when the R/H is down to 26% the water content is at about the 120ppm level.
For some reason on the last batch after the 4 hour drying cycle the R/H was down to only 21% so I tested for water and it was just under the 100ppm level.
I'm pleased with the way this system works as it seems to be reliable in that I know the water level from the R/H.
I have not done tests at every R/H level but the ones I have done have shown;
40% R/H = 250ppm water
26% R/H = 120ppm water
21% R/H = 100ppm water
October 06, 2015, 06:33 AM
Hi Dgs. Is your probe in the liquid its-self?. I was measuring the air that came out of the dryer and the vacuum pump.
I also have a small probe but have to connect it to my computer with a USB cable. I need to get a little reader to put the probe in the liquid. I have heard of others doing this with success.
Now that I have vacuum I am going to use the evaporative and condensing method to measure water in the samples the hope its more stable system.
There is a lot of info on this on sites that dry transformer oil. Moisture is a big problem in transformers and can cause them to catch fire. They have desacating (spelling?) breathers and probes that measure water in PPM cheapest here is $500 us.
October 06, 2015, 06:35 AM
OH PS thanks WesleyB for your thoughts, If we water wash I think all the methanol is gone, however this may be an issue if one dry washes?