Saturday, June 27, 2009

Propellant Progress..

It looks like we have secured another source of 50% peroxide.

The process of turning 50% food grade into 85–90% rocket grade is as follows:

1)Filter the peroxide through ion exchange resin to remove stabilizers.

2)Sparge from 50 to 70%

3)Sparge from 70 to 85%

Step 1 needs to be conducted with the bulk temperature below 70F or the resin tends to catch fire. The low temp at FAR is presently >70F with a high > 100. This leaves the bulk peroxide temperature too hot.  So we took a dewar of Lquid nitrogen out to the desert and cooled and then filtered about 1500lbs of peroxide. We cooled the ulk peroxide by bubblin Ln2 throu from the bottom. We started at 11PM and finished about 6:30 am just as ths sun was comming up. Everything worked exactly as desined and according to the TDS meter we removed the bulk of the stabilizers.  We got back home at about 11:30 am this morning. Its just after 6pm and I just woke up. This all nighter thing worked so much better 25 years ago in college.

We have about 30 minutes more work and we are ready to try step 2. We will proably do this next weekend. I can’t do the final step until the generator I ordered arrives. The 50 to 70% step can be done with filtered “desert” dry air, the 70 to 90 step needs the air to be dryer than that and our big oiless compressor and -100F due-point airdryer system needs more power than we presently have on site.


Timothy J. Massey said...

It's great to hear that you're back in business with peroxide! :)

I had asked before, but it got missed. If you don't want to answer, just tell me to buzz off... How much peroxide will you end up with after concentrating it to 90%? And how long do you think that will last you?

Paul Breed said...

I expect to loose between 25 and 50%.
So 1500 lbs of 50% will make between 350 and 500 ls of 90%

I can reclaim a fair bit of the lost peroxide by adding a condenser at the output of the sparger. I have all the parts to do that, but I'll run it open without the after condenser to start with, just to get going. I expect that the vapor coming off at the 2nd sparging will be on the order of 35% peroxide.

Anonymous said...

Peroxide concentration is a dangerous process.

David said...

Supply issues solved is great. That being considered, I will be most interested in hearing that the concentration process has also helped the issues caused by the presence of stabilisers that have proven to be the cause of limited catalyst life and optimal performance for multiple long runs.

Hopefully this will lead to more flights and an LLC flight profile sooner than later. I know the rules will provide more time than first-in-first served though it would be good to get it out of the way (at least level 1) early.

Fingers crossed for you.

Paul Breed said...

Yes 2O2 concentration is hazardous.
Building rockets is hazardous.
We are using a lower temperature less hazardous process than the normal vacuum distillation. The very design of our sparger is designed to keep us from reaching detonateable temperatures. Given that one could still have contaminates and peroxide thermal runaway,the sparging column has a rupture disk outside of the container pointing in a safe direction. Review US patent #6290820

Anonymous said...

US patent #6290820