OK, that's my misunderstanding of the process. I assumed it was boiled off in the still at a temperature that evaporates ethanol only. The process you describe sounds very high-tech. I wonder how they made their 100% ethanol a hundred years ago :)
I must admit I've never understood what the 95% - 99% refers to. I understand that it's 95% ethanol, but I assumed that the other 5% was the denaturing chemical/s, not exclusively water. Yet that contradicts what I've read elsewhere where it is suggested that 95% methylated spirits contains 5% water.
Regarding stills, I found this:
http://www.dassa.sa.gov.au/site/page...124#production
That might be redundant though.