Cooling water vs Distillate temp

[Antler24]

Ok let me start by saying my liebig is 36" 3/4" over 1/2" with a piece of copper wire spiralled between the two. It knocks down full 5500w of power with cooling water at 3 liters/minute.

I've been trying to run it to get a nice temp gradient the length of the condenser but if I adjust water flow down to where the outlet water is warm to touch, the distillate is almost hot. If I increase the water flow to get the distillate close to room temp, the outlet water is very cold, with little to no temp difference on either end of the condenser.

I don't want my distillate coming out hot, but I don't want to be shock cooling either. Can anyone tell me if I'm running it right or how I should be running my cooling water?

[shadylane]

I feel of the water jacket and adjust the cooling water flow. The condenser should be hot on one end and cold on the other.
There is a point in between were the temp will change rather abruptly.
I adjust the water flow to were temperature change is in the middle of the condenser.

[rad14701]

You might consider adding a spiral up inside the liebig to slow the spirit flow as it condenses, allowing for more contact time... Some folks put a spiraled copper wire up in the entire length... Others make a long copper ribbon out of copper sheet or split, flattened, and twisted copper... Slow the product down and you can slow the coolant flow...

[MichiganCornhusker]

What is the angle of your condenser? If it is close to vertical, adjusting it to a 45, or even more horizontal, will also increase time your distillate is in contact with the cooler copper.

[corene1]

I know this is a silly question but you do have the cool water coming in from the bottom and exiting the top?

[MichiganCornhusker]

It knocks down full 5500w of power with cooling water at 3 liters/minute.

At first I thought that was a typo, and you meant 3 liters/hour for distillate collection. But, do you mean 3 liters/minute of water through your liebig? That seems like a lot.

[Antler24]

You might consider adding a spiral up inside the liebig to slow the spirit flow as it condenses, allowing for more contact time... Some folks put a spiraled copper wire up in the entire length... Others make a long copper ribbon out of copper sheet or split, flattened, and twisted copper... Slow the product down and you can slow the coolant flow...

I do have a small piece of copper scrubby up there, just to split up the vapour.

What is the angle of your condenser? If it is close to vertical, adjusting it to a 45, or even more horizontal, will also increase time your distillate is in contact with the cooler copper.

It's damn near 45* the way I have it setup these days.

I know this is a silly question but you do have the cool water coming in from the bottom and exiting the top?

Yes Corene cool water in the bottom!

[rad14701]

You might consider adding a spiral up inside the liebig to slow the spirit flow as it condenses, allowing for more contact time... Some folks put a spiraled copper wire up in the entire length... Others make a long copper ribbon out of copper sheet or split, flattened, and twisted copper... Slow the product down and you can slow the coolant flow...

I do have a small piece of copper scrubby up there, just to split up the vapour.

Nope... That just helps knock down the vapor and stops surging... I'm talking about something to slow down the condensate so it has more contact time with the cooled copper after vapor collapse... There are several topics that cover adding coiled copper wire or a copper ribbon into the inner copper tube... It will help, trust me...

[Antler24]

You might consider adding a spiral up inside the liebig to slow the spirit flow as it condenses, allowing for more contact time... Some folks put a spiraled copper wire up in the entire length... Others make a long copper ribbon out of copper sheet or split, flattened, and twisted copper... Slow the product down and you can slow the coolant flow...

I do have a small piece of copper scrubby up there, just to split up the vapour.

Nope... That just helps knock down the vapor and stops surging... I'm talking about something to slow down the condensate so it has more contact time with the cooled copper after vapor collapse... There are several topics that cover adding coiled copper wire or a copper ribbon into the inner copper tube... It will help, trust me...

Ok thanks rad I'll do some research on that see what I can come up with.

[skow69]

What is it you're worried about? If you can get cool distillate in a smooth stream with no huffing or other weirdness, why mess with it?

[Antler24]

What is it you're worried about? If you can get cool distillate in a smooth stream with no huffing or other weirdness, why mess with it?

True I guess it's really nothing to worry about, I just wondered if it was normal.

[skow69]

I'd have to call it normal in my experience. I run a trickle thru the liebig. It's hot at the top and cold from there down. It pisses a steady stream so I just never questioned it.

EDIT: I should qualify that. I don't use it for stripping. It's on my VM, which is limited to 2625 watts total, so it could never see more than 1313. 5500 watts is a horse of a different color, for sure.

[still_stirrin]

I agree with Rad....your vapor is moving too fast, i.e. - 5.5kW power into a 1/2" vapor tube (inside your Liebig). That's out of proportion. If you had a couple or 3 of those vapor tubes in the condenser (think "shotgun"), you'd have slower vapor velocity and greater heat transfer to your cooling liquid.

For grins...did you do a calculation on the parent site to see how big the condenser should be for your input power? (see example below).

To (approximately) size the length of a shotgun, use the vapor to liquid contact surface area.

For example: the calculator calls for a 132" Liebig (with 13mm, 1/2" diameter vapor tube), with 15 deg C inlet and 50 deg C outlet (water) and 5.5kW power.
That equals pi x diameter x length; 3.14157 x 1/2" x 132 = 207.3 sq.in.
2 vapor tubes (1/2") requires 66" length for 5.5kW
3 vapor tubes (1/2") requires 44" length
4 vapor tubes (1/2") requires 33" length
5 vapor tubes (1/2") requires 26" length
6 vapor tubes (1/2") requires 22" length
7 vapor tubes (1/2") requires 19" length

You can improve efficiency of heat transfer by adding turbulation in the water side as well as the vapor side. Also, contact time with the heat exchanger (think "vapor velocity") will improve the conduction of heat through the vapor tube's material (copper, I assume).

Bottomline here is that you're overpowering your 3/4" over 1/2' by 36" long Liebig. Hence, the high water flow rate to cool the liquid product. And if you turn the water flow down till the water outlet temperature is where you want it, the product comes out hot...liquid, but hot.
ss

[Jimbo]

Typical 13 gallons in a 15.5g still and I never run the 5500W Camco hotter than 4000. 4000 for stripping, 2000 for spirit runs. A long strip of this (2 feet) crammed up the vapor tube really evens out the flow into a nice cold stream at barely more than a trickle of cooling water. http://www.brewhaus.com/Copper-Mesh-P947.aspx" onclick="window.open(this.href);return false;" rel="nofollow

[skow69]

Jimbo, what are the dimensions of your liebig?

[Jimbo]

Its 3/4 over 1/2", I think the working section of it is about 40", overkill really. I have a copper wire spiraled over the half and copper mesh inside the 1/2. I threw 5500 watts at it as a test and it didnt bat an eyelash.

I did another test by putting my finger over the outlet. If ALL the vapor is knocked down, there will be no pressure buildup at all, just a buildup of liquid travelling up the condenser tube. Which is crazy if you think about it. When liquid boils it expands 1600 times going to vapor, and then collapses entirely back down in the condenser. Maybe its not so crazy but fascinating nonetheless

[skow69]

still_stirrin, does this rig have a reflux condenser? That would reduce your length a lot.

[Antler24]

I agree with Rad....your vapor is moving too fast, i.e. - 5.5kW power into a 1/2" vapor tube (inside your Liebig). That's out of proportion. If you had a couple or 3 of those vapor tubes in the condenser (think "shotgun"), you'd have slower vapor velocity and greater heat transfer to your cooling liquid.

Bottomline here is that you're overpowering your 3/4" over 1/2' by 36" long Liebig. Hence, the high water flow rate to cool the liquid product. And if you turn the water flow down till the water outlet temperature is where you want it, the product comes out hot...liquid, but hot.
ss

That's what I was looking for, great post. I forgot to mention for spirit runs it works flawlessly, I guess I was just pushing it too hard on the stripping runs. Other than wasting cooling water, is there a drawback to running it wide open? I know I've read on here countless times that a stripping run should be ran "as fast as your condenser can handle".

[rad14701]

That's what I was looking for, great post. I forgot to mention for spirit runs it works flawlessly, I guess I was just pushing it too hard on the stripping runs. Other than wasting cooling water, is there a drawback to running it wide open? I know I've read on here countless times that a stripping run should be ran "as fast as your condenser can handle".

Running way too fast could drive more tails into the low wines and more water will come over, diluting the low wines to a lower %ABV... In a perfect world your low wines would be at a %ABV/Proof which would allow the spirit run to blend out to as close to your target drinking %ABV/Proof... Drop those low wines down too far, or pull over too much nastiness, and a third distillation might be required... But not everyone uses this method...

[Antler24]

That's what I was looking for, great post. I forgot to mention for spirit runs it works flawlessly, I guess I was just pushing it too hard on the stripping runs. Other than wasting cooling water, is there a drawback to running it wide open? I know I've read on here countless times that a stripping run should be ran "as fast as your condenser can handle".

Running way too fast could drive more tails into the low wines and more water will come over, diluting the low wines to a lower %ABV... In a perfect world your low wines would be at a %ABV/Proof which would allow the spirit run to blend out to as close to your target drinking %ABV/Proof... Drop those low wines down too far, or pull over too much nastiness, and a third distillation might be required... But not everyone uses this method...

That makes sense. I will say the 5 stripping runs I've done have all ended up between 38-40% abv without diluting. I'll slow it down a bit for the next couple see how it ends up.