How Dry is Your Finished Bio, Really?

[thewormman]

A quick test that may be of interest to some.

I wanted to know if my bio was dry or not after water washing and drying for what I thought was long enough, so I looked at the Wiki for ways to do that here: http://www.biopowered.co.uk/wiki/Water_in_fuel_-_test_kit

Looked great but pretty involved for a quick test. I wanted just a quick way to make sure when I had finished my drying it was dry enough so I came up with the idea of using silica gel beads which change colour when they absorb water. Bought some of these off ebay £9.79 for a kilo.



http://www.ebay.co.uk/itm/380404031305?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I took a couple of jars of washed undryed bio and dropped a small amount in. Jar on right cloudy as washed, not dried, jar on left as washed, not dried but with beads added, has gone clear. This was in an hour or so.



The silica gel starts off orange and goes green as it absorbs the water. I wanted to know if the bio would just dissolve the beads, but they were fine.





So I dried the batch in the normal way I do heat to 60C then spray over a uri gellar diffuser with a blower heater blowing into the top of the drum.



After 1 hour 30 mins I took a sample and put in a teaspoon of silica.





Some green beads showing so gave it another 20 mins



Beads remained orange. Not very scientific I know but a quick way to be reasonably sure your bio is dry. Water can cause internal rusting and corrosion to injection pumps etc. I did try this on some pump diesel as a comparison and ended up with one bead going green.

The kilo of silica beads I bought will probably last me 100 batches so a pretty cheap, easy, quick check. Just keep them in a sealed bag as they absorb moisture from the air, you can though heat them in the oven and use them again. I throw them away and use fresh each time because the smell of burning bio in the kitchen would get me lynched!

[greasemonkey]

I've been wondering about those. The ones that are designed to be put in with plants, will absorb a huge amount of water, and I think it is what is in some of these filters that claim to take water out. the only thing that I wonder about, is does the coating of oil on the stop them absorbing the water?

[Tony]

Interesting.  K.H experimented with absorbing water from bio using various things including silica gel.  That was from the perspective of using them to dry the bio rather than an indicator though.  Interesting that whatever does the colour change indication survived the experience - I wonder how many batches it would last?

[Julian]

Great idea, never occurred to me to use them as an indicator.

The only problem I can see is if methanol is present.  When I played with them (same type with the colour change) for drying methanol, they appeared to have more of an affinity for methanol than water.  They dried the same way ... I used a microwave, but they didn't dry methanol at all.

If you've washed most/all of the methanol will have been removed, but they could give a false reading if it hadn't.

That said, they would still be indicating that one or the other needs removing, may be worth running some test, intentionally contaminating bio to see the results.

I'm happy to replicate any tests you do to verify results.

[thewormman]

I've been wondering about those. The ones that are designed to be put in with plants, will absorb a huge amount of water, and I think it is what is in some of these filters that claim to take water out. the only thing that I wonder about, is does the coating of oil on the stop them absorbing the water?

The good thing with the ones I used was the colour change to show if water is present.

[thewormman]

Great idea, never occurred to me to use them as an indicator.

The only problem I can see is if methanol is present.  When I played with them (same type with the colour change) for drying methanol, they appeared to have more of an affinity for methanol than water.  They dried the same way ... I used a microwave, but they didn't dry methanol at all.

If you've washed most/all of the methanol will have been removed, but they could give a false reading if it hadn't.

That said, they would still be indicating that one or the other needs removing, may be worth running some test, intentionally contaminating bio to see the results.

I'm happy to replicate any tests you do to verify results.

By the time I use them I have done a few washes till wash water is clear, soap tested and dried. I think any meth would be long gone by then. But I will put some in meth, bio with meth, and finished bio as a comparison. No problem be good to compare the same batch

[nigelb]

Good work there Dave. A real nice piece of science. A refreshing approach with real time results..

Whenever I've seen silica gel mentioned it was always about absorbtion...indication is a far better way to use them.

I remember the K.H experiments well....inconclusive at best.

[Head Womble]

Very interesting, I wonder if it could be used to test if the oil is dry before reaction.

[thewormman]

Thanks Nigel

Mark I have a batch of WVO I am drying and processing over Xmas I will try them in that and see what results I get. Might be difficult to see though with a layer of darker oil on them

[1958steveflying]

Great work, good to see from your first pic that not only are they working as an indicator they have also dried the jar of Bio.
 
 Could you weigh them before (when orange) and after (when green) maybe that could give an idea of the amount of water removed.
I suppose that could be tested by adding a known amount of water to a sample then removing it with the Silica Gel and weighing them.

It appears with some other types that microwaving them dries and makes them re-usable. Have you tried that with these ones

I can see his sales rocketing now.

[thewormman]

On the suggestion of Julian I did some testing of the effectiveness of the silica crystals with different amounts of water and methanol present.

With the EN14214 European standard for Biodiesel the following applies

Max water content 500 mg per kg so 0.05%

Max methanol content 0.2%

For testing I used 200ml of biodiesel that had been thoroughly dried and filtered to 1 micron.

Water test less than 0.1% showed no change:

With 0.2ml of water added so 0.10%



With 0.3ml of water added so 0.15% some colour change noted within a minute.



With 0.3ml of water added so 0.15% after 1 hour.





So the colour change is still at 3 times the amount of water allowed under the EN standard, but gives a good indication you are very close. So maybe an extra 20 mins drying may just finish it. Certainly when I have had an indication of water by the colour change I have found an extra 20 mins takes it to a level of no colour change.

When I tested 200ml of biodiesel that had been thoroughly dried and filtered to 1 micron from the same batch with methanol I got these results:

With 0.3ml of methanol added so 0.15%



With 0.4ml of methanol added so 0.20%



No change in colour at all.

If someone else (Julian?) would like to try this and see if it varies due to feedstock/process that would be good.

So for me I find it a quick easy test to see how close I am to having dried it enough rather than just staring at it and thinking yea that will do, other methods and ideas are available 

Anyone want to buy some silica beads? (just kidding)

[oakwoodtv]

It may be that a smaller amount of silica will give a better indication.
A dozen or so rather than the amount you are using.
Then all the water will be concentrated in a few rather than shared by a lot.

Richard     

[Julian]

Happy to replicate the tests, but it won't be until after Christmas now.  Even if it's not quite down to ASM levels, it still looks very promising for a viable test.

I like Richards thinking of using fewer lumps ... logical when you think about it.  I wonder if some lumps have a greater affinity than others?  I have vague recollections of quite a range of colours/shades when they are damp.

[Julian]

Temperature too may have an effect on performance.

[thewormman]

Thinking about this overnight since on my sample of 200ml 1ml = 0.05% if you take your finished sample add your silica beads then using a small syringe add 1ml of water at a time and wait for a change of colour.

So if you add 1ml of water and it changes you already had 0.10% in there. If you have to add 2ml of water you already had 0.05% and if you have to add 3ml your bio was dry.

I think this would be as accurate as the soap test we use which relies on colour interpretation.