Re: Sparging

Ben Brockert wrote:
> If buying a machine is the best route, why is ERPS rolling their own?

A. In deep enough that I'd hate to walk away at this point - I've 
got enough infrastructure in place (incl. working 3-phase power at 
the ranch, now!) and equipment under construction that I may as well 
see this phase through to where I've given my current plan a fair 
test! (even though it's taking a few years longer than I first 
assumed... but that's more due to logistical externalities than 
to insurmountable obstacles in the technical development itself, 
which I must be careful to keep in mind when responding to this 
sort of question: the hard part hasn't been building things so 
much as making the time available to do it.)

B. I think the route we're pursuing will potentially yield extra-pure
(>98%) H2O2 with low impurity levels, as in the last batches XL-space 
supplied before closing: and the "squeaky clean & wicked pure" stuff
has evident potential not only for catalytic work but also for potential
hypergolic combinations. (Everything I've encountered so far leads me
to the conclusion that if lower-concentration material is desired for
use with a particular catalyst, best results will be had with highly-purified
material (by way of a final freeze separation) diluted as needed, rather
than with H2O2 concentrated by evaporation directly up to the intended
strength (unless the evaporation starts with extremely low-solute material).

This is not out of the question: the process used by Bengtsson of
"Peroxide Propulsion Systems" in Sweden involves running the H2O2
in dilute aqueous solution through an ion-exchange "demineralizer"
as is used in preparing purified water: with solutes thus removed,
he then concentrates the solution by evaporation.

As far as the Lozano apparatus, it looks like it's a conventional
lab setup in two stages, first a vacuum flask evaporator set with 
condenser, and second a vacuum still with reflux column - I think 
the idea is to start by evaporating and condensing the supply material
to get rid of solutes and then using the column to distill out as 
much water as possible... operating at a vacuum allows a low enough
temperature to be safe. (The boiling point of pure H2O2 at atmospheric
pressure is about 150 C, and you don't really want a process that 
involves getting the stuff that warm... accidental catalysis of 
pure boiling-temperature peroxide would undoubtedly be a violent 
event, whereas at temperatures much below normal ambient, the stuff 
sort of goes to sleep, at least by comparison.)

Biggest negative IMHO of the Lozano apparatus is using laboratory-style
glass-bulb vacuum flasks, which seem like they could be a bit fragile at
that scale...

-dave w