Rank: Junior Member Groups: Registered
Joined: 7/13/2006(UTC) Posts: 28
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"I have the Essential Extractor II, non-high capacity size, using a 15.5 gallon keg, raschig rings, copper scrubber at top, digital thermometer, gas turkey burner. I am meticulous about monitoring temp between 172 degrees and 180 degrees and and only collect between those temps. I use two water pumps, one for cooloing lines, and one for condensor. Ice and water in a cooler.
During the boil I basically start flame medium and cut down to a maintenance flame right before run off. I run 6 gallons at a time plus any tails left over from previous run.
I have noticed that after 1-2 quarts received, the condensor starts spurting more liquid than the 1-2 drops per second I try to maintain. It will run like a spigot for one second then return to a drip. It surges like this throughout the rest of the boil. I pretty much have the flame all the way down at this point, and water running in the lines. If I run too much water the temp goes down and the system stops. I can hear the rings moving inside the column all the way up to the cooling lines so it seems that the product is gurgling past those and spilling out the condensor along with some water from the column. I have rings all the way up the column until 2-3 inches below the cooling lines where I have placed a copper scouring pad.
Is my temp too hot in that it makes the product bubble up all the way and out the condensor? My temp is cut basically all the way down. Should I increase water flow for cooling and let the temp stablize in the column and come back up on its own? Any suggestions?
Also, during the run the temp stays at approximately 177degrees but will suddenly drop to 170 or so even lower sometimes. I know its better to adjust at the top with flow but if i dont increase temp it doesnt go back up. It seems column surges up and dowm making temp drop up and down. Any help is appreciated!"
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Rank: Newbie Groups: Registered
Joined: 1/2/2008(UTC) Posts: 6
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In industrial strippers, same as a still, the colum will surge if the cooling at the top of the packed colum is to great. When hot vapor condense to a cold liquid, the air volume is reduced creating a vacuum. I'm sure there is a technical name for all this but I have no clue what it is. You can either add a valve to the outlet of your colum cooling pump and reduce the flow, or remove the ice from your cooling tank, monitor your temps and keep them above the lowest pump operating temperature. Your best bet would be adding a valve.
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Rank: Junior Member Groups: Registered
Joined: 7/13/2006(UTC) Posts: 28
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"Thanks for the reply. I have a valve on the line coming from my cooler into the column and turn that down pretty much as the temp goes down, then adjust some when the temp goes up. I had a seperate line running to each inlet on the column but now have routed the lines from one to the next instead of using a line in for lower and one for upper. I have it as one continuos loop now for the top of the column. I have a seperate pump pushing water from the same cooler to the condensor.
If I am understanding what you are saying, you are saying that I should let my temp at top of column get a little hotter? I start collecting at 173degrees and stop about 180degrees. I try to keep the temp between there and fiddle with water flow if the temp fluctuates too much. Should I stop fooling with it so much and just let it ride?
Also my raschig rings are packed to an inch or so below the coolong inlets in the column. Should these be packed all the way up over the lines and just below the condensor inlet?
Im getting some great product, its just the times it surges adds water I think and diminishes my return. Thanks for any comments and help!"
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Rank: Newbie Groups: Registered
Joined: 1/2/2008(UTC) Posts: 6
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"I would try to do a few different things.
[LIST=1]
Run the still at a lower temperature while refluxing. Your colum is getting flooded and the pressure in the pot isn't letting the liquid fall out of the colum. If you're running the heat as low as you can, move the heater further away. Decrease the cooling on the colum. Try putting your colum pump in a seperate cooler with alittle warmer water, and adjust recirculation as you do your run. If you are in a cold area outside, you may want to insulate it in the winter months. Try a natural defoamer like vegtable oils - olive oil maybe - in a small amount incase your pot is bubbling over into your colum. Try to duplicate the problem with water runs instead of alcohol just to be on the safe side. [/LIST]"
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Rank: Newbie Groups: Registered
Joined: 6/19/2007(UTC) Posts: 5
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I have had the same surging isue. If you put a rolled up piece of copper mesh in your condencer, it will help. I have a 4" piece in mine
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Rank: Junior Member Groups: Registered
Joined: 7/10/2007(UTC) Posts: 10
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Also,you are leaving alot of good alcohol in your boiler...I typically collect to about 195 deg.That seems to be about when the tails start to show up...YMMV
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Rank: Newbie Groups: Registered
Joined: 3/9/2008(UTC) Posts: 1
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Cruspeed the term you are thinking of is vapor lock.
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Rank: Junior Member Groups: Registered
Joined: 4/1/2008(UTC) Posts: 20
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I had this prob recently my temp was bouncing from 176 to 178 less than a minute apart I took the rubber bung with the thermometer out of the top of the column (Essential Extractor from brewhaus) and removed some of the copper mesh from the top of the column. It appeared to me that I may have put a little too much in there. I figure the packing was touching the end of the thermometor. The column temp stabilized right away after a slight adjustment with the cooling water the temp was solid as a rock for the next 3 or so hours running at about 90% the whole time.
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Rank: Junior Member Groups: Registered
Joined: 7/13/2006(UTC) Posts: 28
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I purchased the larger Essential Extractor High Capacity model. From what I am reading, if it is vapor locking and not allowing the liquid to fall out of the column back into the pot, with the larger 3 inch diameter on the same size keg, the larger size should allow more downward flow instaed of being restricted by the smaller unit at 2 inches. I will also place some raschig rings in the bottom of my pot to stabilize the boil as some have suggested. I will run the batch and collect at 173 and stop somewhere around 180-185. Have to be careful of unwanted and poisonous liquid that starts to develop in the upper ranges.
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Rank: Junior Member Groups: Registered
Joined: 3/31/2008(UTC) Posts: 23
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"I think tom sawyer has hit the nail on the head. I was a lead chemical operator at the old UpJohn Company and did thousands of distillations. Packing the column to tight is a major and common mistake which causes surging. Take out some of the copper packing and watch the temp and speed of your cooling water for the column.
Second major and common mistake is not knowing what your temp and speed or L/min is of condenser water. We keep good records on every thing else but forget that the condenser water is a huge key to the equation."
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