cold reactions or Drying Potassium methoxide.

[dgs]

Having done many ambient reactions, this link recently came up on infopop. I've heard of using quicklime before as the catalyst but not for drying the KOH type methoxide.


It was developed by Mark Imisides
http://biodiesel.infopop.cc/ev...057046543#1057046543

Sorry folks, link won't work, will see what I can do.

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/1057046543?r=1057046543#1057046543

Thats better.

[willbuild]

Hydrated lime is available in the UK from most builder's merchants.
Its added to mortar renders.

[dgs]

Hi Willbuild,
Is hydrated lime the same as quicklime (calcium oxide)

I think this process yields effectively AKM. If it works It seems very good, although I'm a bit puzzled why this method should work with ambient reactions better, except for using less methoxide. Time will tell.

[willbuild]

I read near the end of the article that hydrated lime was not easily accessible in Australia but that you also use quick lime. Which is easily accessible.

[Julian]

I read near the end of the article that hydrated lime was not easily accessible in Australia but that you also use quick lime. Which is easily accessible.

I think it's the other way round.  Not that I'm an expert, this from Wikipedia.

Quicklime is ... Calcium oxide ... CaO ... also known as burnt lime, when mixed with water forms hydrated lime.

Hydrated lime is ... Calcium hydroxide ... Ca(OH)2, also known as Slaked lime or builders' lime and is what's used in the building industry for mortars and renders (so readily available)

Daves link to Infopop concerns Quicklime.  Therein is another link to using Hydrated lime as a catalist ... Infopop thread ... http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/3397000933   Some experimentation seems to have been done by taralec who I beleive is a member on the VOD and known to Keef on here.  From a very quick read he seems to have had some success with the method.

For my part I've tried using Hydrated lime to dry methanol.  My efforts weren't very scientific and didn't appear to work, maybe Quicklime would have worked better.

It looks very interesting, just wish I could understand it all!

[willbuild]

I used quick lime years ago to make white wash in southern Spain.
We would pour 80 litres of water into an oil drum and add quick lime rocks one at a time whilst stirring and adding another30 litres of water to  6 to 8 kg of quick lime.
The heat generated would make the mix boiler, the white wash would kelp the heat for several days.

[Julian]

In the thread I linked to is a pdf download by Jon T who sumerised the method ...

http://api.viglink.com/api/click?format=go&jsonp=vglnk_145000806081914&key=9bdcc5c751999fa8170ff838157bab8f&libId=ii4h435k0100075t000DA5u991692&loc=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F3&v=1&out=http%3A%2F%2Fwww.mediafire.com%2Ffile%2F8u269y78y55w5we%2FHydrated%2520lime%2520catalyst.pdf&ref=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F2&title=new%20process%20for%20making%20biodiesel%20-%20Topic&txt=Hydrated%20Lime%20Catalyst

He seems to use a massive quantity of methanol though.

[Julian]

I used quick lime years ago to make white wash in southern Spain.
We would pour 80 litres of water into an oil drum and add quick lime rocks one at a time whilst stirring and adding another30 litres of water to  6 to 8 kg of quick lime.
The heat generated would make the mix boiler, the white wash would kelp the heat for several days.

I bought a couple of sacks of premixed lime mortar (assume it was hydrated lime mixed with sand) from a specialist company on the South Downs,  to do some pointing.  It was fantastic stuff to use, way superior to cement mortar and has set like rock, not at all powdery.

[dgs]

I've read all the links Julian, most interesting. Giving this some thought I think that the greatest advantage of all these methods would be using quicklime  (CaO) to dry the methoxide. Using either quicklime or Slaked lime as the catalyst for the main reaction seems a bit of a false economy. After all, using KOH equates to 1 pence/litre to the cost of making biodiesel.

It maybe that when decanting the methoxide from the fines, these could be put into some sort of filterbag and 'hung' in the processor to help with the reaction.

 In anycase the KOH is cheap and I now use a maximum of 12.5% methanol (added) plus what I recover from the glycerol. So if the dry catalyst reduces soap production and increases yield then my process will be another step more efficient.

I've just got to find some quicklime and I'll give it a go, Maybe a 70 to 80 litre batch in my small 120 litre processor.

[Chug]

I discussed this with chemist neutral a few years back when using lime on my strawbale buildings and slaking it ourselves into lime putty, he told me he didn't think it would work and gave good reasons that I forget now.... polarisation maybe..dunno..
anyway I tried adding some to methanol and it didn't mix well at all, tried mixing it in wvo, it clumped and fell to bottom, removed some water but was a right mess to remove, I never got any further as its highly corrosive and you cannot keep it in the open air for long and it was about the same price as NaOH and worse to work with and I wasn't really getting anywhere fast. It was quicklime in powder form rather than freshly made lumplime/quicklime which would be even more of a nightmare to use.

I've still got lime render and lime putty up the field but no quicklime

[dgs]

Thanks for that Chug.
I'm picking up some quicklime on wednesday which I will use to dry the next lot of KOH methoxide. I will report in due course.

[dgs]

Haven't finished all the pre-tests with this method but thought these results are interesting so far.

Reclaimed trinity methanol-2600ppm water.

400 mls of above + 50gms KOH the test at present shows 25000ppm (2.5%) and still rising.
Have to go out now for rest of day but will post tomorrow with the final result of the methoxide water plus what it is going to be after the CaO is added.

25000ppm, Wow, still can't quite  get my head around that.

If this test is correct and we assume the oil was totally dry before adding the methoxide, then at the normal concentrations of added methoxide we are adding around 4000ppm water to the mix!

[dgs]

I have now finished the water tests regarding potassium methoxide drying, Here are the results;

Trinity Reclaimed methanol 2600ppm

methoxide, 400 mls of trinity methanol plus 50gms KOH 31,200ppm (3.12%)

I added 50gms of quicklime to this and stirred for 5 mins then left to settle, 22,200ppm (2.22%)

I then added 100gms of quicklime to 250mls of methoxide, freshly mixed at same ratio as above, this was in a jam jar and I shook the hell out of it for 10 mins then left for the CaO to settle, 4,200ppm (.42%)

So it does seem to work, although not getting the methoxide totally dry. I have a feeling that the 1st test probably wasn't mixed enough.

The most suprising thing is the original water content in the methoxide, 3.12% The last test showed a reduction of water by something like 85%

Next thing would be to try this in a 'real' process.

[Julian]

Good work, Dave!

How will you replicate the vigorous mixing at full scale ... bit dodgy pumping methoxide to mix it?

Will this process work with NaOH?

Do you think it would work for drying bio and would it be economical compared to heating?

[dgs]

I think I will mix the methoxide and lime in cubies, then leave it to settle and pour off the lime-free methoxide. To reclaim the methoxide slurry from the cubie bottom I suppose a filter bag arrangement would be best.

Julian, there are still lime 'fines' left in the methoxide, so it isn't clear even after 24 hours. During the process I'm sure most of it will be removed either with the glycerol or by water washing, but using it to dry the bio would present a problem. The fine bits left in suspension in the methoxide look to me as if they would easily go through a 1 micron filter.

I'm sure this process would work with Sodium Methoxide.

I know Paul did a calculation re the amount of water formed when KOH methoxide is mixed but I don't know how my results compare with the theoretical amount.

I have just found the figures that paul worked out, and adding 50gms of KOH into methanol (assuming the methanol was water free) would yield 16gms of water, so in 400mls of methanol that gives 4%. My result was 3.1% so it's not that far away. Doing a water test with the s/b with water so high means using a very small sample size so the accuracy of the test is less.