Tuesday, 3 January 2012


From the comments on the last post there was some concern about the safety of my setup. I really appreciate these and please  keep these coming because criticism is a excellent way of finding a potential problem.

 I plan on using a consumable catalyst

Sparging in a pressure vessel:
The pressure vessel does have a relief valve, currently set to 130PSI. I should probably lower this, I think all I need is a new spring. After some peroxide came out under pressure however I decided is probably wasn't a good idea to sparge in a closed vessel.

What am I doing to the air:
Two oil dental air compressors (oil free) feed into an an air receiver. The air is filtered by a 1micron filter then fed into a refrigerated air dryer. There is also a 5 micron pre filter on each compressor filter. Currently the setup is running at 60PSI which should put the dew point at around -15C. I plan on increasing the system pressure as the concentration increases to get a lower dew point.

I have tested the setup extensively with distilled water to see if I could catch any contaminants collecting, couldn't see any.

This is probably my greatest concern at the moment. After I initially realised the exhaust was an issue I was bubbling the exhaust through water and venting the exhaust outside (that was when the vessel was closed, with one in and one out pipe). With the open vessel I simply put the entire setup outside and had a large fan to blow fumes away from anyone, which seems to be quite effective and we can't smell anything inside the workshop. Also I only sparge at night when there is no one around. I would be interested in finding out how bad the vapour is for you. VHP is used as a disinfectant so it can't be good, I just figured that because the vapour was not particuary concentrated (initially at least) and that it was being diluted with so much air that it wouldn't be a problem. I suppose I was lucky that my peroxide wasn't too concentrated before I realised that the vapour was an issue.

I think what I might do is:
Sparge outside, further away from the workshop.
Turn the sparge gas off when I need to inspect the rig.

I had the understanding that it was best to filter out contaminants using IX when the peroxide is at as low of a concentration as possible. That is because the IX resin can act as a fuel (i think its plastic) and the IX process can generate heat. Is there any other reason why it would need to be filtered after concentration?

It seems like vacuum sparging would also be a better method because it may increase the speed of concentration., but not necessarily from a safety perspective. The problem people who vacuum distill their peroxide have is that if they loose vacuum, the concentrated peroxide vapour that is safe at vacuum will decompose because it is suddenly at a much higher pressure. That probably won't be an issue as there won't be nearly as much vapour as if the peroxide were boiling. I would appreciate any references anyone has found on vacuum sparging.


  1. If I may make some comments:

    I have deionized and concentrated via sparging over 100 tons of peroxide and supervised technicians who did the same.

    Sparging should not be done in a pressure vessel, even one with a spring vent. Sparging columns typically have a teflon burst disk the diameter of the column itself.

    PVC, nylon, polypro and HDPE are not good construction materials for concentrators. Stainless, glass, and Teflon are.

    Deionizing peroxide is usually the route people end up in the hospital. There is a process out there but this process needs to be trained, not discovered through trial and error. Do not, under any circumstances, deionize over 70%, and do not deionize any % of peroxide unless you have been trained to do so.

    Get a copy of Schumb's "Hydrogen Peroxide" and read it cover to cover.

    Beware of the vapor detonation limits for H2O2. Sparging systems avoid this issue, but what happens if your compressors fail?

    I'm trying to avoid you hurting yourself or worse. H2O2 can be utilized safely but you must have the proper training.

  2. Wise words above, I can't say much more than that.

  3. Just out of curiosity, why don't you buy the H2O2 and focus on the rocket engine?

    Speaking from experience, one can create a new time consuming and even more dangerous hobby than building and testing rocket engines for themselves by trying to figure out how to concentrate peroxide. If that is what you want to do, that is fine, but if you want to build rocket engines, then I would suggest purchasing the propellant.

    I promise that you cannot begin to fathom the tiniest details that will bite you until you get bitten.

    If the price of the propellant seems cost prohibitive to you then I would suggest changing propellants. There is a very good reason it costs what it costs.

    Best of luck!


  4. Thanks for the comment. If it was available I would buy it, but I haven't been able to find any suppliers (in Australia at least) that will even return phone calls. I have heard that %70 is used in the paper bleaching industry, but I haven't been able to find any suppliers. Peroxide is such a great fuel that even after going to the effort to concentrate it I still like it more than nitrous which is really the only other oxidise I have considered.