Environmentally Aquatic Fluidized Bedding

[cranky]

I've run all the cleaning runs, water vinegar, water again and sacrificial alcohol both with and without packing. Like I said, packing is lava rocks and not SPP and maybe that effects things and I have no trouble maintaining a flood all the way to the top if I want. My observations are during the alcohol run only. I get plenty of bubbling and boiling, even the dancing geysers on top, although not as violent as in yours, just no pressure wave like you describe here

Another boundary interface line rose out of the boiler and started up the column, way slower than the vapor, like 2 or 3, maybe 4 seconds per inch. As it rose I could see waves come up behind it, at vapor speed. They would catch up to the slow line and disappear. The slow line was the liquid level (previously known as flood level) climbing the column. The waves were bubbles of vapor boiling out of the pot.

Bubbles yes lots of normal boiling bubbles that I could push all the way to the top of the column but never saw that pressure wave no matter how hard I ran. Like I said, in my 1.5" column I can definitely hear that wave moving up the column but on this 3.5" it didn't happen. When I find the time to run the birdwatchers for a keeper run that may change but I'm still thinking that pressure wave is a phenomenon only associated with smaller columns and perhaps that swirling effect I observed with no packing in the column. Of course I could be wrong, but that's all part of the beauty of this whole process.

[Odin]

Nice thread. The flashing is the result of pressure build up. So this is the level where there's too much liquid in the column (too much reflux, too much power in). Dangerous and causing entrainment. Too tight packing is another cause. This is not what you want to see in an SPP packed column under optimal working conditions.

regards, Odin.

[skow69]

Everybody has a theory. I started this thread hoping to develop a test that would let us compare conditions and give us empirical evidence for what works best. Until then the only quantifiable data I have to work with is product purity. If you're getting azeotrope with no (or minimal) equilibration, how bad can it be?

Skol,
skow

[skow69]

Cranky, I'm having trouble getting a mental picture of what you are describing. For me, the bubbles and wave are the same thing. Bubbles come out of the boiler and give the appearance of a wave as they rise through the column. I suppose the wave appearance results from the vapor displacing all of the liquid in a cross sectional slice of the column at once. That is, the bubble occupies an entire section of the tube from wall to wall. Are you saying that you see individual discreet bubbles rising within the liquid, but they never accumulate into one that is big enough to displace all of the liquid in a given horizontal section?

If that is it, then you are probably right, it would be much easier to propogate "waves" in a smaller column because it would take less vapor to occupy the cross section. Discreet individual bubbles would probably be more efficient because of better mingling, more vapor/liquid interface area. Yet another theory we need to test and quantify.

I get the impression that you don't want to post videos because of the liability that comes with the extra exposure. I respect that, but it is unfortunate. Some of these things are so much easier to discuss with the visual aid. Also, I hope I'm not putting myself in jeopardy. I tend to think of the internet as anonymous, although I know that is not the case, and less so all the time. I guess I'm depending on the idea that the forces of oppression have a lot of bigger irritants to deal with before they get down to small fry like me.

[Odin]

This is not theory for me, it is practice. What we see in your colum, Skow, is the result of pressure build up. Too much reflux. Too heavy. Probably due to compacted packing and hence limited refluxing capability.

Yes, you can reach 96% like that, but it is not a good thing. You don't want them geysirs. Why? Because the will cause entrainment (I think the word is). All of a sudden bursts of vapour shoot through. You get the horizontal equivalent of the normal pitfall of vertical vapour channeling, resulting in smearing of tails into hearts.

A stable "fishtank" is needed to stop all those bullets shooting up from the boiler. If that's not the case, you get unbalanced HETP's. At one moment it is 2 inches, at another it is just 1 inch. up and down. In fact pressure build up and an unstable reflux bed at top and bottom of column constantly destroy low HETP build up. Also the pressure induced will up/down output as well as up/down actual azeo. Now that does not have to be an issue, at the early parts of pressure build up. I an get my rig to produce above 96.5%. 97 and even 97.5% at around 2.8 kw in an ultraclean column were achievable. But a stable fluidiced beds without geysirs and flash channeling as in your video need to be prevented.

I have a measurement device for pressure in my rig, so as to prevent (excessive) pressure build up from happening. And my SPP packing is less than 1 1/2 inch from take-off. Never any issuess with entrainment, because I manage the column in such a way that no pressure build-up takes place.

Your work of making / trying to make the workings of advanced packing understandable is admirable. Great job! Compliments and kudo's!

Regards, Odin.

[cranky]

Cranky, I'm having trouble getting a mental picture of what you are describing. For me, the bubbles and wave are the same thing. Bubbles come out of the boiler and give the appearance of a wave as they rise through the column. I suppose the wave appearance results from the vapor displacing all of the liquid in a cross sectional slice of the column at once. That is, the bubble occupies an entire section of the tube from wall to wall. Are you saying that you see individual discreet bubbles rising within the liquid, but they never accumulate into one that is big enough to displace all of the liquid in a given horizontal section?

That is exactly what is going on.

If that is it, then you are probably right, it would be much easier to propogate "waves" in a smaller column because it would take less vapor to occupy the cross section. Discreet individual bubbles would probably be more efficient because of better mingling, more vapor/liquid interface area. Yet another theory we need to test and quantify.

I believe so, much like Odin calls a "fish tank" effect. That's also why I mention the swirling which took approximately the same amount of time for the swirl to make a complete rotation as the space between those waves in your column making me think the two may be related.

I get the impression that you don't want to post videos because of the liability that comes with the extra exposure. I respect that, but it is unfortunate. Some of these things are so much easier to discuss with the visual aid. Also, I hope I'm not putting myself in jeopardy. I tend to think of the internet as anonymous, although I know that is not the case, and less so all the time. I guess I'm depending on the idea that the forces of oppression have a lot of bigger irritants to deal with before they get down to small fry like me.

Yes, sorry Google already knows too much about me without the videos. I wish it were otherwise but sadly efforts have yet to get this hobby legalized and I don't trust youtube or google or the government. Never trust a government or a corporation.

One other thing, Odin thank you for your input in these matters, I greatly appreciate your opinions and input in just about everything..

[Hound Dog]

Never trust a government or a corporation.

Don't sweat it. Google teamed up with he NSA already knows..... Ohh, what's that?.... I hear another drone. I'm getting my shotgun.

[cranky]

Never trust a government or a corporation.

Don't sweat it. Google teamed up with he NSA already knows..... Ohh, what's that?.... I hear another drone. I'm getting my shotgun.

Fortunately I'm in a drone no fly zone but I had to switch my tinfoil hat for gold foil to keep major league baseball satellites out.

[skow69]

Odin, welcome to the conversation. Thanks for stopping by.

I like the word "flashing" for the dancing geysers. I think we should adopt it as standard terminology.

Your points need a little fleshing out for me to discuss. I've always had trouble accepting any declaration as gospel truth without compelling evidence, preferably numerical.

Pressure buildup.
I will assume you refer to pressure in the boiler.

Because the will cause entrainment (I think the word is).

Not sure where you are going with this. I thought entrainment was liquid splashing from one plate up to the next higher one.

You get the horizontal equivalent of the normal pitfall of vertical vapour channeling,

Horizontal channeling? Help me out, Odin.

A stable "fishtank" is needed to stop all those bullets shooting up from the boiler.

I noticed you made a reference to this analogy in another thread. I get the impression that there is a post somewhere discussing bullets in fishtanks. I google searched fishtank, found lots of info about ferment heating, but nothing on packed columns. Got a link?

But a stable fluidiced beds without geysirs and flash channeling as in your video need to be prevented.

I'm pretty sure you didn't mean to say that we should prevent beds without geysers. And I don't know what flash channeling is.

I do happen to have some insights about pressure oscillations, but I would like to get a handle on the conversation up to this point.

I have a measurement device for pressure in my rig, so as to prevent (excessive) pressure build up from happening.

What sort of device is it? And what reading does it give you?

Your work of making / trying to make the workings of advanced packing understandable is admirable. Great job! Compliments and kudo's!

Thanks for the kind words. I'm just trying to find out what options are available, and then (ideally) determine a method to evaluate them. Some things have to be quantified before I can believe in them. They just aren't real for me until there is a number attached. It's the difference between science and superstition, or science and sophistry.

[skow69]

Google already knows too much about me without the videos. I wish it were otherwise but sadly efforts have yet to get this hobby legalized and I don't trust youtube or google or the government. Never trust a government or a corporation.

I could not agree more.

[Odin]

Hi Skow,

I will try to be clearer! Here we go:

Entrainment is where liquid spatters up and onto/into the next plate. With the geysirs in a way the same is happening. Liquid splashes up from the colum (instead of dripping down from the column cooler), and enters the take-off system.

With modern packing vapour channeling can be a problem. More power in means more reflux. More reflux means less open space. More power in and less open space in the column create very high vapour speeds. If there is not enough reflux to cover the packing, challels or gas chimneys may develop, where the gasses shoot right from the boiler to the take-off point.

Actually, maybe it is not just "not enough reflux". Part of its cause is reflux that is not distributed well enough. Think about a small diameter column running too big SPP ...

When there is pressure build up inside the column, the liquid beds will go up and down and gasses (pressurized) will come off in waves (the flashes you see) instead of at a steady rate. Imagine too big a liquid bed on top. Weight as well as inpenetrability by the gasses underneath create pressure. That pressure and the energy put into the rising gasses by heating the boiler can go out in only one direction: through the too big liquid bed. Too big a liquid bed AKA column flooding creates pressure ... and then that pressure is released, shaking up the bed and lifting it slightly (geysirs). Compared to a steady situation without column flooding you now get limited gasses traveling up ... then LOTS of gasses being released. The pressure lifting the liquid bed up can create its own channeling. That's what I meant by the horizontally caused channeling. Not a good word choice, I now feel. Pressure induced vapour channeling might be better. Caused by column flooding. Where not enough reflux creates vapour channeling just because there's not enough liquid to stop the bullit.

The bullit in the fishtank ... I thought I posted about that but I can't find it either. It is a metaphore that I find very helpful in explaining what goes on in a modern packed column. As oposed to the theory with loosely packed scrubbers of old, where we felt that surface area of evaporation of the total column packing was what created efficiency. I will put up a post later today. In this tread if that's fine with you. Explaining how I got to it and how it helps me understand what might be going on.

Regards, Odin.

[Kegg_jam]

Hi Skow,

I will try to be clearer! Here we

This information was very enlightening. Ever since watching Skow's first video's I've been trying to wrap my head around what's going on in the 'aquatic environment'.

I too believe the 'farts in a bathtub' wave is pressure related and not such a good thing.

[skow69]

Odin, by all means, post it here. This seems like an appropriate place.

Just for the record, let's remember that I have never advocated running with the column fully flooded. I've been trying to define and compare "aquatic" with "fluidized" and "flooded", and to identify the factors that promote these conditions. All this in preparation for developing the test to evaluate efficiency. If you want to explore all the possible points on a line, you end up at the extreme ends at one time or another.

[Odin]

I completely agree, Skow, and you do a great job at helping everybody understand how this works. We have come such a far way already. I remember when I first posted that the surface area maximalization theorie does not hold in modernly packed columns, half of the world, including this forum felt they wanted to cut my liver out!

Ah! the one organ I can't miss.

Maybe more on the metafore later. I have some business to attend to first. Darn and it's almost 10 pm already!

Regards, Odin.

[skow69]

I do remember that. I was taking bets on crucifixion over burning at the steak. Such heresy.

[Odin]

... and now we are discussing it openly and nobody is burning us! Great development. And what I like is that, like this, there's again some more talks on innovations taking place. I feel that has been lacking a bit of late.

Regards, Odin.

[Kegg_jam]

If you want to explore all the possible points on a line, you end up at the extreme ends at one time or another.

I'm with ya skow. I explored that line till I blew out a flour paste seal. I learned to dial it back a bit. But it was fun to watch the geysers dance around for a bit...

[skow69]

Not sure I'm ready to bail on the flashing just yet. More trials ahead.

[soul_gelatin]

Hey this was a great thread that helped explain what I have been seeing and if it was a good thing... And I was wondering @skow69 if you had any updates!