Alcohol Vapour leak

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Alcohol Vapour leak

Postby artooks » Wed Nov 22, 2017 7:35 am

Hi Everyone,

I am having a problem with my CCVM Still's boiler, I purchased my reflux boiler from Mile hi it is a small 3 Gallon Boiler, I use it with my CCVM setup, the only difference is I made a special PTFE Gasket for it, because it comes with silicone gasket and we do not want it, anyway, during the initial heat up everything seems to be ok, once the vapour starts to go up in the column after a few moments the alcohol vapour starts to come from the some parts of the lid, I unscrew and screw the clamp of the lid and then everything seems to be ok, but I could not really understand the actual reason why it does this, maybe I think the vapour is hardly go up at first but that also does not seem very logical, maybe it is due to my custom made PTFE gasket but than again I do not experience this when I run it as a pot still maybe because there is less pressure ? What do you think guys what should I do to improve this situation because I really becomes dangerous, I would appreciate any help on this.
Thanks
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Re: Alcohol Vapour leak

Postby RedwoodHillBilly » Wed Nov 22, 2017 8:41 am

It could be differential expansion. During heat up on my stills, I tend to tighten all of the clamps a couple of times. I don't get leaks this way. You may want to re-tighten the clamp(s) during heat up and see if this helps.
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Re: Alcohol Vapour leak

Postby NZChris » Wed Nov 22, 2017 12:00 pm

If you have a vapor leak, the first instinct is to try to tighten everything to stop it, but the problem may be that you have pressure where there shouldn't be any.
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Re: Alcohol Vapour leak

Postby still_stirrin » Wed Nov 22, 2017 3:29 pm

NZChris wrote:If you have a vapor leak, the first instinct is to try to tighten everything to stop it, but the problem may be that you have pressure where there shouldn't be any.

Thinking "out loud" here...like Chris suggested, you may have more pressure in the boiler when configured as a reflux still. You've obviously added a column, with a certain height packed with some form of packing. This all forms a "resistance" to flow for the vapor. When that happens, the boiler will build back pressure until the vapor once again begins to flow up the column. Remember, "pressure" is the motive force for flow...and that is created in the boiler.

Perhaps your packing is too tight? Can you blow through the column without too much difficulty?

When you "force" the situation, you may encounter dangerous conditions. Take a closer look at your setup. Chances are...your PTFE covered silicone seal is not the cause of the leak...only the collateral damage of the greater concern.
ss
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Re: Alcohol Vapour leak

Postby Pikey » Wed Nov 22, 2017 7:11 pm

still_stirrin wrote:
...........Perhaps your packing is too tight? Can you blow through the column without too much difficulty?


Yep - packing too tight !
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Re: Alcohol Vapour leak

Postby artooks » Wed Nov 22, 2017 7:46 pm

Thanks Guys for all the suggestions, I will give you details about my column because I find this situation quite dangerous, so I would appreciate some help here, first of all I do not have a PTFE covered silicone, I have a PTFE gasket that has been cut out from a sheet panel, which works perfectly when there is no reflux, I have a 36" long stainless steel column, I use three things in my column.

1) Copper Scrubbers - 14 Scrubbers
2) Copper Saddles - 200 Gram
3) Raschig Rings - 300 Gram

And the order I place them in the column from top to bottom.

Packing top to bottom:

1) 4 Copper Scrubber
2) Copper Saddles - 200 gram
3) 3 Copper Scrubber
4) Raschig Rings - 300 Gram
5) 7 Copper Scrubber

This is it, I did the blow thing, but will do it again, I could blow through but not very easily but will do again an let you know, the strange thing is once I unscrew and take that pressure out it then works ok, so can't quite understand why it works ok after that, but must also say that the liquid which falls back to the boiler is very thin, I do not know if this makes an important details, so here it goes, I could start with 95 ABV and finish at 94 ABV with this setup, so what do you think about this packing ? what do you suggest ? is this packing too tight that it creates pressure ? if so what should I change ?

Thanks
Attachments
3.jpg
Copper Scrubbers
2.jpg
Copper Saddles
1.jpg
Raschig Rings
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Re: Alcohol Vapour leak

Postby NZChris » Wed Nov 22, 2017 10:32 pm

If the back pressure from the combination of the type of packing and the reflux is too high, you can cut back on the power.

It might only be a problem before the packing in the column gets up to temperature. I have to reduce the Amps to my Boka just before the boiler reaches the boiling point of the charge. If I don't, the temperature in the boiler goes higher than the predicted boiling point and I hear bubbling in the column.
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Re: Alcohol Vapour leak

Postby artooks » Wed Nov 22, 2017 10:56 pm

I usually start heat up with %100 reflux would it help to start with %50 reflux or no reflux at all at the initial heat up ?
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Re: Alcohol Vapour leak

Postby Corsaire » Wed Nov 22, 2017 11:45 pm

artooks wrote:... I could blow through but not very easily...

I don't have a reflux, so I don't really know for sure, but maybe you should put less packing in there? See if it helps? And maybe test with water instead of alcohol.
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Re: Alcohol Vapour leak

Postby kimbodious » Thu Nov 23, 2017 2:34 am

Try breathing in and out through your packed column, like a big snorkel. Packed too tightly for sure :econfused: . My 48" x 2" column has 22 stainless steel scrubbers, your 36" column has 14 scrubbers plus all that other stuff
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Re: Alcohol Vapour leak

Postby artooks » Fri Nov 24, 2017 1:28 am

Thanks would it help to start heating as usual and turn it down once it starts to boil and also maybe to keep the reflux %50 ? then after when the whole column heats up I could go into %100 reflux ?
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Re: Alcohol Vapour leak

Postby NZChris » Fri Nov 24, 2017 2:14 am

What works for my marbles is cutting the heat to 50% as soon as the bottom of the column starts to warm up, then letting the heat rise slowly up the column, feeling the progress with my hand. Once the heat reaches the top, I can turn the power back up.
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Re: Alcohol Vapour leak

Postby still_stirrin » Fri Nov 24, 2017 9:29 am

I’m kinda’ like Chris too.

I start at full heat until the column starts to warm (30 to 45 minutes). As it starts to boil (you can hear the “swooshing” in the boiler, I reduce heat to start stacking the column...probably 50-60% power (I monitor amperage on the controller).

Once reflux is established, I’ll bring the power back up to70-80% full power to further compress the heads. And then, slowly begin drawoff through the LM valve. I keep the power at this setting (70-80%) so I don’t overrun the reflux condenser, yet maintain as high of reflux ratio as possible to push the %ABV upward.

I’ll pull foreshots and a portion of the heads before closing the LM valve, stabilizing again, and then slowly open the VM valve. From then, it’s a simple collection of the product at the outlet. But, I have marble packing, so it flows relatively easily.

I suspect your packing is simply too tight. You’re getting falling condensate slugging up the rising vapors as it collapses. The density of your packing is requiring you to reduce the vapor flow to balance the flooding conditions.
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Re: Alcohol Vapour leak

Postby artooks » Sat Nov 25, 2017 12:28 am

Hi,

Today I start another spirit run I run at full power at the beginning then when I relize that it started to boil I cut back the power, at this stage only the boiler is reach boil level but the column is still cold then I cut back the power as NZChris suggested, it really helped but when the heat reach the middle of the column I started to see a few drips coming from the lid, right and left side, also I saw vapour also but at a very slow flow rate but it is still there, so the situation got better but the problem is still there, normally I unscrew and screw the boiler lid clamp and then the situation becomes ok, I reach %100 reflux but can't really understand why it does that if the packing is too tight it should flood, but I blow the column after I pack it and it seems ok, I can blow through, but the problem is still there, what can you recommend as this is really frightening, what can I try next ?
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Re: Alcohol Vapour leak

Postby artooks » Sat Nov 25, 2017 12:43 am

The strange thing is once it reaches a certain heat and the reflux starts it works ok but the problem occurs at the initial heat up, then it is ok
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Re: Alcohol Vapour leak

Postby artooks » Sat Nov 25, 2017 7:30 am

still_stirrin wrote:I’m kinda’ like Chris too.

I start at full heat until the column starts to warm (30 to 45 minutes). As it starts to boil (you can hear the “swooshing” in the boiler, I reduce heat to start stacking the column...probably 50-60% power (I monitor amperage on the controller).

Once reflux is established, I’ll bring the power back up to70-80% full power to further compress the heads. And then, slowly begin drawoff through the LM valve. I keep the power at this setting (70-80%) so I don’t overrun the reflux condenser, yet maintain as high of reflux ratio as possible to push the %ABV upward.

I’ll pull foreshots and a portion of the heads before closing the LM valve, stabilizing again, and then slowly open the VM valve. From then, it’s a simple collection of the product at the outlet. But, I have marble packing, so it flows relatively easily.

I suspect your packing is simply too tight. You’re getting falling condensate slugging up the rising vapors as it collapses. The density of your packing is requiring you to reduce the vapor flow to balance the flooding conditions.
ss


Thanks SS, but the thing is I could blow off the column with ease, and also, once heat travels all the way up in the column then I do not have any problem at all, the reflux starts and I start to collect no vapour escape after that point my actual problem is at the beginning of the first heating up.
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Re: Alcohol Vapour leak

Postby ben stiller » Mon Nov 27, 2017 2:39 pm

Are you 100% sure that the problem goes away and no vapor is escaping? I would keep a mirror handy and check around the lid throughout your next run. If the mirror fogs you have vapor escaping.
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Re: Alcohol Vapour leak

Postby Skipper1953 » Mon Nov 27, 2017 6:16 pm

Your packing is too tight at the bottom of the column. When you first start up, the seven scrubbers (too tight) get flooded by the condensate falling from the much looser packing (rings) above. While you are screwing around unscrewing and rescrewing the clamp, heat continues to rise through the packing. When you resume applying the heat, the vapor travels a bit further up the column and as a result is not flooding the scrubbers at the bottom as it condenses and drips back down the column.

That is my wild assed guess as to what is happening. Loosen up those first seven scrubbers and the problem will go away. Better yet, put one, maybe two scrubbers at the bottom, one scrubber between the rings and the saddles and then put the rest of the scrubbers at the top of your column. Or, still better, put one or two scrubbers at the bottom and then fill the rest of the column with 1/2 inch glass marbles.

JMHO. YMMV.
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Re: Alcohol Vapour leak

Postby artooks » Tue Nov 28, 2017 12:00 am

Hi,

Thank your Skipper1953, I have been concentrated to find the problem and luckily I found it, turns out that I have created the problem, but the reason I did it to get rid of the silicone gasket and cut out a new %100 PTFE gasket in my friends router, of course the dimensions becomes tricky in this type of application, the reason being is because the supplied silicone gasket is being pressed inside the lid and also has lots of grip compared to PTFE after several attempts I found the right size but this time the height is a little bit problematic, therefore when I take the boiler upside down I see that at two points it grabs the lid perfectly but at once point it barely holds, so this brings the issue when screwing I have to align the lid perfectly not to have a problem that I mentioned, there is not problem with flooding my only problem was the alignment of the lid with the gasket to the boiler during clamping. I did two runs after I realised this and the problem is solved, took a lot of work really by cutting using PTFE gasket to be %1000 safe which is very important.
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