Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: nigelb on February 24, 2013, 07:12:57 PM
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It is quite clear that in the past few weeks I've upset some people with the way I defend and promote my water washing methods. For that I make no appologies.
What I've been trying to do is to inform and educate biodiesel producers as to the ease of water washing without the intervention of unnecessary chemicals.
Don't get me wrong..I'm not against experimentation dispite the comments of some on both this and the VOD forums.
Following comments made by Mark regarding the unusual figures gained through soap testing during acid water washing I made a statement on this thread...http://www.biopowered.co.uk/forum/index.php/topic,966.msg986... saying that I'd do a soap test after each wash on my next batch. I've stated many times that I typically do 4 washes to complete a 150lt batch.
As I'm not on a meter I use standard tap water, but ,due to bleating on the VOD by senior members over the years about wasting valuable resorces, I have used, in the past, water harvested from the roof of my shed that is stored in a water butt. That argument does not stack up and should not be used by anyone arguing or discussing the merits of water washing.
So..this Friday (22.2.13) I made a 150lt batch of fuel using the two stage no titration method. I dried my fuel using 13lts of dry glyc from the previous batch and used 18lts of methanol and 3.0lts of ASM for stage 1 and 0.5lt of ASM and 3.5lts of methanol for stage 2. This resulted in a perfect 5/45. No dropout...no haziness just a clear solution when the bio was added to the methanol.
What was I expecting when I started the testing?
I expect that the soap levels would be lowered following each water wash....but would my claims of water washing be backed up by scientific testing?
I took a sample to be tested from the raw biodiesel just after it had been transfered to the wash tank but before any water was added.
Before washing:
4.4ml of 0.01N HCl = 1337.6ppm of soap.
After 6 hours of gentle washing the first lot of water was drained from the tank, a sample of bio was taken from the top and was tested for soap.
1.35ml of 0.01N HCl = 410.5ppm of soap
Following an overnight wash (16.00 Sat to 07.30 Sun) wash 2 was drained. The water looked very soapy and I skimmed some soap from the top of the bio. While prepping some more water I turned up the air supply to allow any remaining soaps to be distibuted evenly throughout the solution before a sample was taken to be tested.
0.25ml of 0.01N HCl = 76ppm of soap
Dispite its low value of soap ppm's the bio did not look like it was close to being finished.
The third 10lt of water was added at 07.30 and was bubbled until 12.00. When the water was drained the bio looked much closer to being finished and a test was conducted.
0.15ml of 0.01N HCl = 45.6ppm of soap
I then heated the fuel to 55°C and added 10lts of hot water. I then put on the lid of the wash tank and turned on my central heating pump and pump washed for about an hour. The water was drained and a sample taken from the top following a period of aggitation to guarantee an evenness of soap throughout the solution. A titration test showed:
0.05ml of 0.01N HCl = 15.2ppm pf soap.
I have to admit that I've never tested like this before ie titrated soap tests at each wash. The results are pretty good and back up the claims I've made over the years.
Conclusion:
4 washes (40lts)
soap reductions from 1337.6ppm to 15.2ppm
wash period: 10:00 Sat - 16:00 Sun. (now drying)
Nige
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Very interesting Nige, it's backed up my thoughts on the acid wash messing with titrated soap test results.
Until now I've had nothing to cross reference against, and had no idea what soap levels raw bio would typically contain.
To give you an idea of what I mean, these are the results I got
124.64ppm after the acid wash,
54.72ppm after wash 1
94.24 after wash 2.
Wash No3 tested at 59.24
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Compairing Nigel's results to mine it suggests that the acid may get washed out by the second wash.
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Good set of results.
Not dismissing your results, Mark, but what would be interesting would be for Nige to try other methods on soap removal with his plant, process and chemicals and record soap ppm at similar stages or frequency. That should give quite a good comparison of the efficacy of each method.
Would make quite a nice wiki page ... you up for it Nige?
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Conclusion:
4 washes (40lts)
soap reductions from 1337.6ppm to 15.2ppm
wash period: 10:00 Sat - 16:00 Sun. (now drying)
Nige
Totally vindicated Nige, that proves Acid/Acetone washing is NOT required for the average home brewer.
I tried it and didn't get on with it at all, never again or until I've set up for your gentle wash method.
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nice write up there nige, interesting to see how long you bubble for, i guess by you using 4 x lots of water isnt to disimilar to me using 4 lots of water but pump washing instead of bubble washing which is more aggresive, may i ask once you have finished bubble washing do you tend to lose a small amount of bio in the water wash, as i tend to start with 100litres of bio and end up with about 95litres...
cheers
glenn
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Conclusion:
4 washes (40lts)
soap reductions from 1337.6ppm to 15.2ppm
wash period: 10:00 Sat - 16:00 Sun. (now drying)
Nige
I tried it and didn't get on with it at all, never again or until I've set up for your gentle wash method.
Perhaps if Nige were to quantify his gentle bubble wash method others that have an interest may reproduce it.
IE: What air volume ? pumped through what stone/bubble device at what level in the Bio.
I was surprised to see that you pump washed the 4th though !
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Thanks for your comments gents. Some interesting points raised and questions asked.
I'll address your points first Steve. The volume of air cannot be acccurately gauged or even guessed at. I use a Hailea pump..I think it's a 75lt/min version but it's controlled by an aquarium control valve so hardly ever pumps at full tilt. I use a 50mm cylindrical ceramic air stone that sits on the bottom of the wash tank. The 4th wash is the hot wash and ever since installing this set up have always pump washed the last cycle. It has always guaranteed the soap levels drop that little bit further due to the emulsion the water and bio form. It's a bit like a huge 50/50 shake-em-up test.
As a side point and something I mentioned to Mark in another thread, I recorded, on my lads xacti, my wash tank with all its components and an example of what gentle washing should be and also an example of washing that is likely to cause an emulsion. My lad and I still have to edit that footage. As soon as we do, it'll be on his utube channel and I'll post a link.
Glenn...I hardly lose any fuel in my washing. With gentle agitation there is less likely hood of an emulsive layer...resulting in a clear division of where the water stops and the bio starts.
Julian...in the interests of comparrison I'll give some of the other methods a go...would you message me as to what you want me to do.
Nige
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Nige, it's quie easy to messure the volume of air being pumped,
hold an inverted (but full of bio) cylinder of a known volume above the air stone,
and time how long it takes to displace the bio with air,
you can then calculate the lpm of air flow.
Yes I know it's going to be a bit messy, but it's all in the name of science.
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Settling would be dead easy to do and could be done two ways ... with and without 7% prewash.
Without 7%
Finish the batch as normal, pump out to your wash tank, bubble overnight to demeth (no water) and simply leave for the soap to settle, testing for soap with a similar frequency as your first test.
With 7%
Process as normal but before draining glycerine, add 7% water and pump for 15 - 20 mins. Settle and drain glycerine, then as above.
See how those go then maybe try an acid wash.
Marks idea for checking flow is probably better, but you can measure flow with a variable area flowmeter or rotameter, you get similar things on professional mig sets I think. A company call CT Platen made the ones I played with in a former life. I've been looking for a small instrument for years to measure flow round the vapour circuit.
This type of thing ...
(http://www.aalborg.com/images/products_overview/P%20Meter.jpg)
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I've been looking for a small instrument for years.
Tried looking in y'pants?
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I've been looking for a small instrument for years.
Tried looking in y'pants?
Commando me.
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I've been looking for a small instrument for years.
Tried looking in y'pants?
Commando me.
Wow! That's brave of you looking in a Commando's pants, did he know?
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Marks idea for checking flow is probably better, but you can measure flow with a variable area flowmeter or rotameter, you get similar things on professional mig sets I think. A company call CT Platen made the ones I played with in a former life. I've been looking for a small instrument for years to measure flow round the vapour circuit.
This type of thing ...
(http://www.aalborg.com/images/products_overview/P%20Meter.jpg)
Are they glass inside?
I've got a flow meter on my Argon bottle regulator (not the dial type) but the internals are all plastic pipe, which would be pretty poor with Methanol vapour. I guess it would be best after the condenser but all the same.
It would be nice to know the gas flow rate, that's for sure.
And sorry for crashing the water washing thread with talk of condensers ;)
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They vary in my experience. I have a couple which are uncalibrated and operate as flow switches via a reed switch. They are far too large for the venturi application but they have glass bodies.
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Settling would be dead easy to do and could be done two ways ... with and without 7% prewash.
Without 7%
Finish the batch as normal, pump out to your wash tank, bubble overnight to demeth (no water) and simply leave for the soap to settle, testing for soap with a similar frequency as your first test.
With 7%
Process as normal but before draining glycerine, add 7% water and pump for 15 - 20 mins. Settle and drain glycerine, then as above.
See how those go then maybe try an acid wash.
Those two tests are a no. Reasons are :
1. I'm not set up for demething and settling. The settling soap would block up my fuel oulet which is in the centre of the bottom of the tank.
2. Soap testing would be nothing short of inpractical due to only being able to take samples from the top of the fluid. This will be soap free very quickly if demethed effectively. Correct me if I'm wrong but soap settles from the top to the bottom. I'm not in a position to sample from part way down the tank.
Comments please.
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GL seems to suggest this stratification of soap settling, but I've never personally seen it. My bio has always been consistent in it's soapyness throughout (aside from the solid stuff at the bottom, or a layer of cream on top of that).
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James may know? don't his tanks have take offs down the side for that reason?
I did suggest labelling them week 1, week 2 etc but i wouldn't want to start an argument :D
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I've just been thinking about this problems while having a shower and came up with exactly the train of thought Keith. I was just about to post up and see that you already have. :D
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My bio has always been consistent in it's soapyness throughout (aside from the solid stuff at the bottom, or a layer of cream on top of that).
Is this backed up with soap tests, observations or 50/50 tests Tony. Trying to get my head round it.
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Excellent result's.
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Excellent result's.
Thanks.
I have used this method for 2 winters now but never had a clue how much soap was in my bio so thought it was about time to find out.
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Excellent result's.
Thanks.
I have used this method for 2 winters now but never had a clue how much soap was in my bio so thought it was about time to find out.
What is your wash procedure and what drying process do you use ?
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Excellent result's.
Thanks.
I have used this method for 2 winters now but never had a clue how much soap was in my bio so thought it was about time to find out.
What is your wash procedure and what drying process do you use ?
When I start washing the bio is still hot, about 75 degrees, after wbd.
I mist spray 20 to 25 litres of cold water into top of processor at a rate of 2 litres a minute. I then leave it to settle for 40 minutes and then drain. Takes 1 hour to fill, settle and drain.
I then do that again twice more.
By the time I do the 3rd and last wash the temp of the oil is down to about 50 degrees.
When draining I stop the moment I see the creamy stuff between the water and the bio coming out. I dont wait until I see bio. I found I lose bio if I do that.
The only time I got an emulsion was when I turned the pump on when water was in the processor so I never turn it on now when washing.
I dry my bio by pumping into an open top settling tank via a spray bar. When the tank is full I then turn heater on and get the temp to about 60 degrees while circulating through the spray bar with a fan blowing across the top. I have had clear bio after an hour but sometimes it takes longer.
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Excellent result's.
Thanks.
I have used this method for 2 winters now but never had a clue how much soap was in my bio so thought it was about time to find out.
What is your wash procedure and what drying process do you use ?
When I start washing the bio is still hot, about 75 degrees, after wbd.
I mist spray 20 to 25 litres of cold water into top of processor at a rate of 2 litres a minute. I then leave it to settle for 40 minutes and then drain. Takes 1 hour to fill, settle and drain.
I then do that again twice more.
By the time I do the 3rd and last wash the temp of the oil is down to about 50 degrees.
When draining I stop the moment I see the creamy stuff between the water and the bio coming out. I dont wait until I see bio. I found I lose bio if I do that.
The only time I got an emulsion was when I turned the pump on when water was in the processor so I never turn it on now when washing.
I dry my bio by pumping into an open top settling tank via a spray bar. When the tank is full I then turn heater on and get the temp to about 60 degrees while circulating through the spray bar with a fan blowing across the top. I have had clear bio after an hour but sometimes it takes longer.
Clearly a good quick process and nice low soap PPM's for mist washing. :)
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I made a batch of bio today and thought that I would play with my new soap testing kit when doing the water wash.
This is the results.
I first did a 2 stage no tit and got a clear pass. Then did wbd and then 7% pre wash. After I drained the glyc/water I took a sample of the bio and tested for soap.
As expected it was high.....2400ppm.
After 1st wash it was....304ppm
After 2nd wash it was....96ppm
After 3rd wash it was.....54.4ppm
Total time spent washing.....3 hours
By the time I need to use it (next week) more soap should settle out.
Fantastic results there Soft top.
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GL seems to suggest this stratification of soap settling, but I've never personally seen it. My bio has always been consistent in it's soapyness throughout (aside from the solid stuff at the bottom, or a layer of cream on top of that).
That's precisely the reason for the take off points at different heights on my settling tanks.
Though only tested with 50/50 tests, I can draw of the top section,25ltr after a clear water test but the next valve down will return a fail.
Stratification of soap IS true as the Master says.
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GL seems to suggest this stratification of soap settling, but I've never personally seen it. My bio has always been consistent in it's soapyness throughout (aside from the solid stuff at the bottom, or a layer of cream on top of that).
That's precisely the reason for the take off points at different heights on my settling tanks.
Though only tested with 50/50 tests, I can draw of the top section,25ltr after a clear water test but the next valve down will return a fail.
Stratification of soap IS true as the Master says.
What sort of settle time is that after?
I ask because even with a warm reaction sample settling for the 3/27 test, while the glycerol sinks there is clear stratification until settling is complete a couple of minutes later.
Surely the same should apply to cold bio soap settling but over a much longer period of time?
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Following good scientific testing practice I've done a follow up set of titrated soap tests on the batch I made this weekend. I made attempts at testing the biodiesel prior to the 7% post reaction wash which I'll publish in a seperate thread.
The biodiesel was, again, made with ASM and I used the two stage no titration method. The final quality test (45/5) was crystal clear, no dropout or haziness. Each wash used 10lts of water.
Test 1
Raw biodiesel having been treated with a 7% post reaction water wash.
2.8ml of 0.01N HCl = 851.2ppm
Test 2 (after wash1)
After 6hrs of gentle bubbling (wash 1)
1.5ml of 0.01N HCl = 456ppm
Test 3 (after wash 2)
After 10hrs of gentle washing (wash 2)
0.55ml of 0.01N HCl = 167.2ppm
Test 4 (after wash 3)
After and overnight wash (wash 3)
0.07ml of 0.01N HCl = 21.28ppm
Because of the low level of soaps in wash 3 I decided not to bother with my usual hot pump wash. It's always nice to reduce the number of steps in the process.
Nige
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Very interesting results Nige.
I'm thinking this information should be on the water washing page in some form to give an idea of what to expect when following this method.
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Very god results there Nige, a testament to your methods.
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Very good results there Nige, a testament to your methods.
When you keep it simple the results are favourable.
A lesson to be learnt here for some...don't over complicate your process.
Nige
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Don't know if I've missed something but when you'all have been testing at successive water washes for soap has the bio been wet with water(orange juice) or dried(clear) before measuring out for the soap test.
Thinking about replicating the test with my multiple water wash arragement. Just want to compare like with like test method.
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I tested the wet orange juice.
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Bill...all testing on my part was done with bio straight from the wash tank. In answer to your question...orange juice.
I think the danger of testing with a dried/demethed sample would be that any soaps present may well drop to the bottom of whatever you have the sample in and could effect the results.
Nige
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After seeing Nige's results I thought I'd do some tests of my own.
I started with 200L of condenser dried and gly washed oil,
add 3.5L of ASM and 24.5L of meths for the first stage,
0.5ml dropout in the 10/90,
200ml of ASM and 4L of meths add for the second stage,
30min later crystal clear 10/90
I only got 20L of gly out on the first stage (normally 30 to 35 with NaOH),
as I wanted to do a 5% water prewash I added a few liters of gly from the first stage back in so not to form an emulsion.
I took samples at each stage for soap testing.
Raw bio, 1.2ml used (0.61 x 10 = 6.1) 6.1 x 304 = 1854.4ppm, quite surprised at this as I thought it was low compared with Nige's results, so I tested it three times and used the highest result.
5% Prewashed bio 1.77 x 304 = 538ppm
1st wash 0.62 x 304 = 188.48ppm
2nd wash 0.22 x 304 = 66.88ppm
3rd wash 0.04 x 304 = 12.16ppm
All stages were pump washed with 20L of water.
So including the prewash I've used just 70L of water on 200L of bio.
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After seeing Nige's results I thought I'd do some tests of my own.
I started with 200L of condenser dried and gly washed oil,
add 3.5L of ASM and 24.5L of meths for the first stage,
0.5ml dropout in the 10/90,
200ml of ASM and 4L of meths add for the second stage,
30min later crystal clear 10/90
I only got 20L of gly out on the first stage (normally 30 to 35 with NaOH),
as I wanted to do a 5% water prewash I added a few liters of gly from the first stage back in so not to form an emulsion.
I took samples at each stage for soap testing.
Raw bio, 1.2ml used (0.61 x 10 = 6.1) 6.1 x 304 = 1854.4ppm, quite surprised at this as I thought it was low compared with Nige's results, so I tested it three times and used the highest result.
5% Prewashed bio 1.77 x 304 = 538ppm
1st wash 0.62 x 304 = 188.48ppm
2nd wash 0.22 x 304 = 66.88ppm
3rd wash 0.04 x 304 = 12.16ppm
All stages were pump washed with 20L of water.
So including the prewash I've used just 70L of water on 200L of bio.
And no emulsions at all with pump washing. very good mate. no acid too.. even better.
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Hifly (Vince) was the first to do it, or go public with it anyway.
Read this thread
http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=26828
So I thought I'd give it a try as ASM is supposed to produce far less soap to start with.
Overall I'm very pleased with the outcome.
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Congratulations Mark. A great set of results.
I suppose I am also quite relieved as it backs up what I've done for years. This should keep any "Doubting Thomas's" quiet. As Steve says...no acid! And no acetone!
What do you plan next Mark...doing the same tests with a bit of acetone? Or stick with this method for a few batches?
Interesting.....the ppm value of the raw bio! I'm looking forward to doing that test again when I next batch up.
How long did it take from start to finish with the washes (as a complete process) and what were your settling times when the pump was turned off?
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I plan to do a few more batches like this t hopefully prove it's not a one off.
The raw bio result was supprising,
I tested it three times a double checked the calculations as I was sure I'd got the decimal point in the wrong place to start with.
Just to make sure could you check them for me,
1.2ml of bio was used (10% of the normal volume),
lowest amount of 0.01 acid solution used was 0.55ml (1672ppm), highest was 0.61ml (1854.4ppm).
As far as using the acetone goes, seeing Julians results of doing further washes after the acetone wash spurred me on to try this myself,
I had the same result as Julian, so I'm now wondering if the acetone holds the soaps in suspension for a 50/50 test,
but as the titrated soap tests were done after an acid wash (the acid wash interfears with the soap tests) these looked good as well.
This is why I've removed the acetone washing page from the wiki, at least until more tests can be done.
My daughter has hidden her acetone as she said I was using to much of it, so I can't backup my theory on this as yet.
I did the batch on Thursday, gly washing in the morning then reacting later in the day, then prewashing and settling over night, dog walking and other stuff was done as well so I couldn't devote the hole day to bio.
Friday I did the three washes and dried it (with condenser) and bubbled off the remaining water overnight.
Each wash was pumped for 30 min and settled for at least 2hrs.
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What sort of pump are you using and what's it's flow rate? Was the pump going full tilt throughout the washes? I'm asking because I may have a go at pump washing.
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I plan to do a few more batches like this t hopefully prove it's not a one off.
Good man..that's the way forward with any sort of experimentation and testing ;)
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What sort of pump are you using and what's it's flow rate? Was the pump going full tilt throughout the washes? I'm asking because I may have a go at pump washing.
I have a 110plm centrifugal pump, and run the eductor during all the wash stages.
The eductor gives me over 500plm of mixing, that's 2 1/2 x batch volume per minuet (educator dimensions and flow calculations from our Jim).
So all washing was quite vigorous, looking back I was lucky to get away without an emulsion on the first wash,
it does prove the method quite well with this in mind.
First wash was at about 45°C.