Sciencemadness Discussion Board

Distilling water

Archenemy_6 - 30-3-2017 at 20:20

So I decided to distill some tap water in my pressure cooker and instead of getting some metal tubing to connect to it I purchased some vinyl tube since it would be easy to connect to the lid. I left it mostly coiled going through some ice water and it seemed to be working well. I left it alone for longer than I should have. When I checked on it the ice water was really hot and steam was passing straight through to the collection jug which was really hot. I stopped it and let everything cool and now my once clear vinyl tubing has turned an opaque white. A quick Google search said something about heat and stress and crystalizing but my question is do you think this would affect future distillations? Could this contaminate the water running through and should I just get some metal tubing?
Thanks

XeonTheMGPony - 30-3-2017 at 20:42

Yes, water is 944btu per pound, you need to remove a crap load of heat, either glass or stainless steel if you want fairly pure water, or reduced pressure atmosphere.

One way you can do this is run it with no cooling water till it is all hot and steam exciting, then seal off and turn cooling water on, will crash the pressure inside the system and increase flow through of the system.

(Must have safety reliefs when doing that)

but plastics tend to leach compounds when hot.

RogueRose - 30-3-2017 at 21:06

Is copper not adequate for this? It's used in a lot of distillation applications, especially alcohol.

I've seen the vinyl tubing turn white with alcohol and it did flavor the alcohol somewhat but I wasn't sure if it leached b/c of the alcohol, heat, water or combo of all.

I'd look at a coil of copper of SS with a fan blowing on it if you don't have a pump or condenser.

XeonTheMGPony - 30-3-2017 at 21:14

copper for alcohol usually isn't worried about a few stray ions and contaminants, depends on the purity of the water you're aiming for, and for generally high purity water I have only ever seen stainless steel (316L I'd bet) or glass.

but if purity isn't so much an issue to that extreme then sure copper, Aluminium would be fine.

Archenemy_6 - 30-3-2017 at 21:26

Thanks for the advice. I'm not looking for extremely pure water I am mainly trying to save myself a trip into town to get some. If I could do it easily at home and without spending much time or money on it then I would rather do that. I'd have to look at the cost and see if I could find a way to attach the tubing and have it easily removable for when I needed it as a regular pressure cooker.

XeonTheMGPony - 31-3-2017 at 04:45

then 6 feet of 3/8 copper tube and a fan will be fine

Booze - 31-3-2017 at 08:53

It would be easier to go and buy a jug the next time you are out. I use my glass distillation apparatus if I have ran out of water to use.

I know you said you don't want ultra pure water, but if you change your mind then build a water electrolizer and capture the gasses, then burn the gasses slowly and capture the water produced. That would be super-pure water!

alking - 31-3-2017 at 09:41

Most plastics will leech into solution at elevated temperatures, it doesn't take much. This is why if you leave a plastic water bottle in a hot car it taste bad, I think it happens at only 40-50C or so, far below boiling.

Praxichys - 31-3-2017 at 10:36

Why not use tap water? Is it not pure enough for your application? Generally all potable water is pretty good for chemistry unless you're doing analytic work, or if the dissolved ions will affect the reaction or catalyze side reactions, etc.

If I'm collecting a product by distillation or by precipitation/filtration, I don't give a darn what's in the water unless it's going to end up in the product. Besides, most amateur work is done with tech-grade hardware store chemicals with contaminants in much higher concentration than you might add by using tap water.

Booze - 31-3-2017 at 13:03

Quote: Originally posted by Praxichys  
Why not use tap water? Is it not pure enough for your application? Generally all potable water is pretty good for chemistry unless you're doing analytic work, or if the dissolved ions will affect the reaction or catalyze side reactions, etc.

If I'm collecting a product by distillation or by precipitation/filtration, I don't give a darn what's in the water unless it's going to end up in the product. Besides, most amateur work is done with tech-grade hardware store chemicals with contaminants in much higher concentration than you might add by using tap water.

And even then you could recrystalize or distill the chemical. I use H2So4 drain cleaner and KNO3 stump remover to make my nitric acid.

macckone - 1-4-2017 at 10:40

Copper tubing works but some reactions do not like copper.
Distilled water is easy to buy.

NEMO-Chemistry - 1-4-2017 at 10:58

http://www.ebay.co.uk/itm/50-75-100gpd-4-STAGE-REVERSE-OSMOS...

?

Liamatpm - 3-4-2017 at 05:27

I would just buy distilled water, it costs (here in the US) 89 cents a gallon at Walmart. It's easy to do that and it is fast and cheap. While distillation is slow and takes awhile.

Archenemy_6 - 9-4-2017 at 18:37

As far as using tap water my tap comes from a well and it's pretty hard water. I don't drink it I only use it to shower really and wash some dishes. Even when I brush my teeth I use drinking water.
I use my well water to wash my glassware thoroughly and then rinse it with distilled to try to get rid of all the hard water. If I just let it dry it would be so dirty.
I could buy distilled water but then I'd have to go into town and last time I went to buy some gallons I went to two places and there were none on the shelves. Plus I don't really like going to the store anyways.
I ended up buying 20ft of 1/4in copper tubing and a few fitting to fit my pressure cooker. It seems to work pretty well and I'm happy with the results. If I left it running for 12 hours I think I could get a few gallons out of it.

Sulaiman - 9-4-2017 at 23:25

It sounds like you have plenty of spare space,
have you considered a 'solar still' https://en.wikipedia.org/wiki/Solar_still

Archenemy_6 - 10-4-2017 at 06:09

Hmm I hadn't really considered that. It is getting quite warm around here and there's plenty of sunlight.