Winter HMPE meltdown

[Head Womble]

I have HMPE's forming in my drying tank (formally settling tank) that was cleaned out before I started titrated water washing.

Now this is only my second batch and I had problems with my first one (details allready posted),
but I still WBD at 85°c before washing.

Due to the recent drop in temps I can't say if there's more now than when I was settling .

[Carrington]

Hi mark
If your up for trialling something I have a idea that sould eliminate the hmpe's , I just have to get my head round wbd and water wash.
If I can get you to prevent the formation then you met not need to water wash.
Can I ring you in few days

Paul

I think the amount iproduced is down to the de-meth so we have to prevent them forming here

[Head Womble]

You have a PM.

[julesandtash]

My short journey into Whole Batch Demeth, especially when added to two stage no tiration processing was the only time I experienced significant HMPEs.
There seems to be something about the WBD process.

Glyc washing seems to be a far more energy efficient way of making use of the excess methanol without problems with HMPEs

I am now down to only 40 litres of methanol per 300 litre batch (using Sodium Methylate and Glyc wash) which means 1500litre of bio per barrel of methanol

[Glycer-rides]

I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.

Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.

Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:

WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!

[Julian]

I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.

Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.

Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:

WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!

Where did that bit of info come from?

He's (assume it's a he) mentioning things I've never even heard of before!

[Carrington]

WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!
[/quote]

Yer you know what he's probably right

[Glycer-rides]

I've got no proof or logic as to why, but I'm sure high de-meth temperatures encourage the formation of HMPE's.

Well I won't be doing another WBD for a while. It was done mainly to test the speed / efficiency of the new coil in tank condensor.

Have none of the proper chemists put up any theories? I was trying to think and Google round it earlier and the best I could arrive at was:

WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type.
But that happens with hydrogenation, whereas during WBD the bio gets pumped full of air which is the opposite....I'm out!

Where did that bit of info come from?

He's (assume it's a he) mentioning things I've never even heard of before!

'He', Julian? I'm flattered.
Came across that stuff in one of those 40 page academic research papers. I remembered the 2 types from A level organic chemistry 30 years back.
I doubt it's that simple or the Industry would have a fix for 'bio from solids', instead of additives.

[RobPerrie]

A question

is WBD when u drain all the clyc and recover the meth from the whole batch before dumping out into a settling tank..

rob

[Julian]

Hi Rob, welcome to biopowered.

The answer to your question is No and Yes!

With WBD, once you have a 3/27 pass, you go straight into demething the whole shooting match, both Glycerin and Bio.  The original method devised by Chug, advises to only recover Methanol down to the stoichiometric quantity, ie leave enough Methanol in the batch to prevent a reverse reaction.

In reality, many people have taken demething further with no reported ill effects.

The wiki page covering WBD is here ... http://www.biopowered.co.uk/wiki/Whole_Batch_Demeth

[Chug]

I ended up with about half a bucket full of HMPE's from two batches last winter during the cold snap when it went below freezing, I kept them to one side and they all melted back to liquid bio and were used up by the end of May.

I WBD and go up to 85-90°C when demething and don't get any HMPE's until the temps drop below freezing when I would naturally expect to have them drop out at as the temp falls below their relevant melting points.

[RobPerrie]

Hi Rob, welcome to biopowered.

The answer to your question is No and Yes!

With WBD, once you have a 3/27 pass, you go straight into demething the whole shooting match, both Glycerin and Bio.  The original method devised by Chug, advises to only recover Methanol down to the stoichiometric quantity, ie leave enough Methanol in the batch to prevent a reverse reaction.

In reality, many people have taken demething further with no reported ill effects.

The wiki page covering WBD is here ... http://www.biopowered.co.uk/wiki/Whole_Batch_Demeth

Thanks Julian, its rob from the other forum, now as im more bio, ive joined this one too.

ok, so Paul if you are seeing this, then it looks like i dont do a WBD, as i drop all the clyc after my 10/90 and then demeth..

so the experiment you want me to try may not work..

rob

[1958steveflying]

As I read it the Author of this is actually saying

1."WBD upsets the reaction equilibrium, which skews the equal isomer balance of cis and trans unsaturated alkyl isomers present in the bio towards the trans type, which have a higher melting point than cis type."
2. "But that happens with hydrogenation"
3. "whereas during WBD the bio gets pumped full of air which is the opposite"
4. "I'm out!"

So he is still saying it does not make sense to him  ! !

[Carrington]

[quote ]

ok, so Paul if you are seeing this, then it looks like i dont do a WBD, as i drop all the clyc after my 10/90 and then demeth..

so the experiment you want me to try may not work..

rob
[/quote]

Hi rob
It's not just wbd that get hmpe's , and the experiment will be a lot easer on just bio de-meth than it would be in the whole batch , if it sl goes well then I will start work on the wbd method.

Paul

[nathanrobo]

I've had HMPE's (if that's what they really are) after very thorough mist washing, but they have only occurred at very low temps (I guess -5 deg and worst).    PF, do you think that what's dropping out at higher temps are different to what's dropping out at very low temps.