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EFFECTIVE DRYING

This topic can be found at:
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/8361026472/m/5497074083

September 28, 2015, 08:29 AM
Braam
EFFECTIVE DRYING
I have recently started making bio and ran into some proplems with the drying of washed bio. I then buit a dry tank consisting of a 120 l open top,used water geyser,fitted a pump at the bottom with piping to circulate the diesel from the bottom to the top, spraying over a ball like surface.I added a heater element, set at 60 deg C, at the bottom and an extraction fan above the tank.This worked fairly well and I was get readings of +- 200ppm water on my manometer.I was impressed , but, after accidently leaving the test sample in the manometer for 2 days I found that the reading climbed to 1600ppm.So I tried another approach. Heating the bio without circulation up to 70-73 deg C for an hour, at which stage the snap ,crackle and pop noise has ended, and then start ciculating at that temp for two hours.Eureka, I had bio dried to an average of 180-200ppm water.I bubble-wash my bio approx 4 times and get ave soap test readings of 20-28ppm soap.Hope this will be of assistance to anybody out there.Happy brewing.Braam RSA
September 28, 2015, 01:35 PM
Sam Sleeman
Hey Bramm I'm in JHB brewing Bio. I'm making 200lrts at a time. I bubble dry the Bio with silica jell beads in the bubbler air stream on the suction side. I never had great success with the manometer, very eratic results. Any way contact me, do you have any experience with Palm oil?
September 28, 2015, 06:01 PM
Tilly
Hi Braam,

quote:
Originally posted by Braam:
...I was get readings of +- 200ppm water on my manometer.I was impressed , but, after accidently leaving the test sample in the manometer for 2 days I found that the reading climbed to 1600ppm.
That is interesting. I wonder where the extra moisture came from.
This does seem to put a bit of a question mark over how accurate the manometer is.
I wonder if any testing has been done along these lines.



quote:
So I tried another approach. Heating the bio without circulation up to 70-73 deg C for an hour, at which stage the snap ,crackle and pop noise has ended, and then start ciculating at that temp for two hours.Eureka, I had bio dried to an average of 180-200ppm water.
Did you allow the test sample to stand for a couple of days to see if the reading increased over time?






September 29, 2015, 06:24 AM
Dgs
I use a similar drying method to Sams, based on IMB's turbodryers. I use a cheap R/H sensor above the extraction fan, when the reading of 26% is reached the bio is just over the 100ppm mark. I dried a batch 2 days ago and R/H got down to 25% after 4 hours. I checked the bio with S/B and it was 105ppm.

Braam, well done with your water levels. I test lots of samples for people and have found that the method you use can be a bit hit and miss. As to the inconsistancies with the manometer, I found the same, so bought the S/B and a K/F.
September 29, 2015, 07:24 AM
Braam
Tilly , thanks for responding on my input. Yes I did leave the test sample for another 4 days and the result stayed constant. Bear in mind that average outside temperatures in our area averages 38 deg C.So I monitored the reading every 4 hours for 4 days. Looks like heating the bio to over 70 C really helps evaporating the emulsified water.Good luck.
September 29, 2015, 07:35 AM
Braam
Sam Sleeman , hi glad to make contact with a locol brewer. Yes I found that the manometer is not THAT consistant but after I had my sample tested at a lab we found that there was a 15 - 20% difference.I can most certainly live with that. As for using palm oil , only tried it once and achieved same results as with sunflower oil.
September 29, 2015, 04:28 PM
Biotom
this increase in pressure with more time is not unique the imake manometer, the sandy brea does the same thing. The instruction state to read the pressure in ten to 20 minutes after you have started the test. Apparently any increase after that time doesn't count? go figure, confusing? yes,
The sandy brea and imake manometer only detect free water. Possibly the bound water is reacted over time, I can think of no other reason for the increase in pressure over time. hope this helps.

This message has been edited. Last edited by: Biotom,


" 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.
September 30, 2015, 12:34 AM
Sam Sleeman
Hi Biotom. As I understood it the whole purpose of the carbide based test was to determine the amount of bonded water. Did I understand incorrectly? In Imakes discussion I understood this was the main reason for this test. Sam
September 30, 2015, 01:29 AM
Tilly
This is an interesting tidbit of information:

"Interaction of Calcium carbide with methanol to give calcium methoxide is vigorous , but subject to an induction period of variable length.
Once reaction starts, evolution of acetylene gas is very rapid, unpublished observations [Bretherick 1995]".

http://www.chemicalbook.com/Ch...rty_EN_CB5854217.htm

It seems that the increase in pressure over a longer time period (several days) is a result of the methanol and Calcium Carbide producing acetylene.
So it seems that the short time reading is the result of mostly water content and the longer time period reading over several days is the result of water and methanol content






September 30, 2015, 02:10 AM
Sam Sleeman
Thanks Tilly. Any documentation on Cabide and dissolved water?? which was in a way the whole point to the test.
September 30, 2015, 02:46 AM
Tilly
Hi Sam,

That is a good question.
I have not seen any meaningful testing that demonstrates whether or not the Carbide manometer tests for dissolved water in oil.

If, as biotom says, the manometer only detects free water and not dissolved water, then it is of limited value to people in europe






September 30, 2015, 10:34 AM
Dgs
quote:
Originally posted by Biotom:

The sandy brea and imake manometer only detect free water.


I really don't know where you got that information from Tom, but that just is not so. Many times I have confirmed readings between my S/B and K/F which have been around the 100ppm mark. As biodiesel holds around the 1000ppm water (depending on temperature) before it becomes suspended then all the water readings done with the S/B that are low are indeed detecting dissolved water.

Both the S/B and K/F will detect dissolved, suspended and free water.
September 30, 2015, 11:17 AM
Braam
sorry for being ignorant but when testing the dryness of the bio, is it not supposed to be methanol- free after washing and evaporation during drying? What I do to reduce methanol in my bio is to add 3% water to the bio after reaching complete reaction,mix it for 5 to 7 min and let it settle out overnight.The water binds to the methanol and settles out with the glyserine, less soap problems. Also , I understand that calcium carbide only reacts with water to form acetylene.
September 30, 2015, 12:37 PM
Dgs
quote:
Originally posted by Braam:
sorry for being ignorant but when testing the dryness of the bio, is it not supposed to be methanol- free after washing and evaporation during drying? What I do to reduce methanol in my bio is to add 3% water to the bio after reaching complete reaction,mix it for 5 to 7 min and let it settle out overnight.The water binds to the methanol and settles out with the glyserine, less soap problems. Also , I understand that calcium carbide only reacts with water to form acetylene.


Indeed Braam, you are correct. If checking the water content of finished biodiesel then however it is finished it should be methanol free, or as free as it needs to be within our relevant area's specs. If the water content is also within our EU specs (in England <500ppm) then indeed this water will all be dissolved.

Both the Manometer and S/B will detect dissolved water. The chemicals involved will not discriminate between dissolved, suspended or free water.
September 30, 2015, 12:55 PM
Sam Sleeman
Hi Bramm. The addition of water stops the reaction reversing and binds up the methanol. However when I do that I always make an emulation. depending on how sever the emulsion is I break it with more water & heat to about 40deg C. I then wash three times. then bubble dry. If I make sever emulsion I brake it with salt & water, then wash and then bubble dry. I found adding 3-5% water makes washing easy but I drain off the glycerol before adding water. I am building a vacuum processor which is now ready for testing.
September 30, 2015, 04:59 PM
Biotom
Dgs let me quote "The test can be performed on any liquid that is not based on water. Any fluid can be tested as long as the following requisites are met; a the water must be in the form of free molecules or droplets and not chemically or physically bound; b the fluid should not attack the water vessel components which are anodized aluminum, Viton gasket, and brass.
The manometer works on the exact same principle as the sandy brea.
This information is from the Sandy Brea Laboratories Inc.

Tilly nice find on the reaction of methanol and calcium carbide.


" 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 01, 2015, 08:12 AM
Dgs
Tom,
I see that on my instructions, I think the bit about the water being physically bound is confusing us. It obviously isn't correct as otherwise there would be no reading with bio that has low water.
It's probably the addition of the anhydrous petroleum distillate that is the key (however the test works well wlthout it)

I've asked Graydon to comment so we can clarify.
October 01, 2015, 11:08 AM
Biotom
quote:
I think the bit about the water being physically bound is confusing us

Not sure what you mean, what is confusing, there is free water and bound water this topic has been discussed many times before, if I remember correctly it is the free water that causes problems and bound water was almost impossible to get rid of without great expense. Also, oils have varying amounts of 4 main fatty acids, saturated fat; linoleic acid; alfa-linoleic acid and monounsaturated fat. One of these will result in more bound water than the others. I'll have to go back through my notes but I think it is linoleic acid? If so , canola oil has 21% linoleic acid where as safflower oil has 76%.


" 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 01, 2015, 12:07 PM
Dgs
Tom,
I have many times checked the water content of my finished bio with both the S/B and the K/F. The K/F is certainly more accurate, but the S/B is more than accurate enough.

I do many water tests, mostly for members of the UK forums.

When doing these comparitive tests I have usually had readings of within 5% and all are within 10%.

Virtually all the tests are within the 500ppm level. If the S/B only detects free water where does this reading come from if there is no free or suspended water in there.

It costs me about 0.5 pence a litre to dry my biodiesel down to just over 100ppm (bound water)
October 01, 2015, 12:22 PM
Biotom
quote:
Virtually all the tests are within the 500ppm level. If the S/B only detects free water where does this reading come from if there is no free or suspended water in there.It costs me about 0.5 pence a litre to dry my biodiesel down to just over 100ppm (bound water)

the way I see it is you have dried your biodiesel to 100 parts per million of free water. For example the hot pan test, "no crackle" it is 500 ppm or less free water.
How can you test for chemically bound water?


" 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.