From what I gather most people have it at the head of the condenser right before it hits the cooled section. I have mine monitoring the pot/process temperature ala GL's method. AFAIK you should not have it at the bottom of the condenser. Jon
Doh! I missed your post DD. I never even though about a reflux column in the mix... I dont use one... I guess the idea is to precicly control the temp at the top of the reflux to ensure only methanol and not water is passing by? Just out of curiosity what is the ideal temp at that point when using a reflux column? Jon
I will have to set up a thermometer to see what the temp is at my condenser head just out of curiosity. I have a heat trace that externally heats the 3' section of 1/2" iron pipe that leads up to my condenser head to 175F when I am dewatering and I usually turn it down to 150 when I am demething... Maybe I should turn it up to 152 to 155F instead? Jon Here it is in complete disarray this spring but you get the idea...
HA! Now that I am looking at my own picture (and wondering what the wire to the top of the pipe is) I remember that the TC for the pid thats controling the heat tape is hose clamped right on the 90 at the top... Jon
It goes pretty quick already My purity is always great between 98 and 99%. But I never pay alot of attention to the heat tape temperature and after thinking about it I probably should! I should add that I am vacuum demething... I bet this would effect what the head temp should be, no? Where did you get the 152 to 155 figure? I bet there is a chart somewhere that shows what the condensation temp is at different negative pressures... Jon
Originally posted by Jon Heron: Doh! I missed your post DD. I never even though about a reflux column in the mix... I dont use one... I guess the idea is to precicly control the temp at the top of the reflux to ensure only methanol and not water is passing by? Just out of curiosity what is the ideal temp at that point when using a reflux column? Jon
I'm not sure what would be ideal but at 150F I have a nice steady stream coming out of the condenser. It will stay at 150 for a while then gradually increase in temp. At around ~165F, I divert the flow and continue until the head temp is around 190. The stuff (tails) that comes out from 165-190 is added to a batch of glycerine to be distilled later.
Location: central virginia | Registered: March 13, 2008
Jon, not a chart, just what I have read here. Dk does any where from 151-155F, as do others and they are getting ~99%. I doubt vacuum would affect the head temp, it shouldnt change the vapor temp at all. The vapor temp is what determines the purity So far, out of 68 gallons glycerin, I have recovered about 15 gallons methanol. Started up at 10am, up to temp at 11am. So far just under hrs total, and figure I have about 4-5 more gallons of pure stuff to pull off. Ill let it go till about 10pm, and shut her down. Its usually about 12 hrs for pots this size.
Cool, I got it. Vacuum makes a huge difference in pot temp but the head temp is always the same if your distilling pure methanol. It took me awhile to wrap my head around that one! THIS POST helped allot! According to the thread I linked above methanol condenses at 149F so my 150 setting was pretty damn close it seems(Lucky!)! I will pay more attention to the head temp next time I brew... Cheers, Jon
The 150-152F comes from me. It's the temp I keep the head at when demething glycerine. THIS IS NOT THE POT TEMPERATURE. The pot gets considerably higher than that to 260-265F by the time it is done. By running the pot that hot you are guarenteed a sterilised product in the end should there have been any bacterial growth that didn't get neutralised in the BD making process. If you are making soap with the demethed glyc I strongly advise running it hot to thwart any potential problems down the road should anyone get jealous and get Health & Welfare/Consumer Protection to look at you. Besides, it is just the responsible thing to do if you are presenting a product to the public that could have health concerns if not done properly.
ditto..I also run 150-152 head temps..I just don't run the pot temp that high..the pump will not take that temp..so I stop at 205 pot temp.
this 15x temp is measured at the top of my 5' reflux column.
all temps are controlled using PIDs and thermal couples.
'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died.. 8.23.11 bus driven to scrap yard ) 2006 Jeep Liberty CRD - the wife's 99 dodge 2500 5.9l 24v..-mine everything run B100 when its warm enough
Location: RTP, North Carolina | Registered: December 15, 2004
I have about a 15" reflux column before my condenser (can't go higher - hitting the ceiling). Runs about 150-152 degrees at the top of the column before going into the condenser. I push my pot temp to about 230-240 degrees and usually the temp at the top of the reflux column climbs to about 160. I tried glass marbles for a while in my reflux column but switched to copper scrubbies. The copper scrubbies seem to give me slightly higher methanol purity.
We just took our still apart and the glass marbles are somewhat pitted. We were thinking about using all copper scrubbies or metal ball bearings. The few copper scrubbies we had in there only had a little patina on them.