Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

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Andrew Seltzman
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Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman » Sat Feb 29, 2020 10:26 pm

I have been working on some upgrades to my gas handling system, pressure feedback control, and deuterium generation. I am aiming to move away from piezo gas control valves towards proportional solenoid valves for deuterium flow control and to build a digital PID control system for valve control to replace the existing analog control system (this will be discussed in a later post).

Even though I can order tanked deuterium, I have been interested in compact storage in metal hydride and generation from heavy water. I recently grabbed a Hydrofill Pro hydrogen generator on ebay and bought some metal hydride cartridges to store the deuterium. The Hydrofill Pro is designed to charge reusable metal hydride cartridges. Each will hold 10L of deuterium, but still fit the the palm of your hand. The Hydrofill Pro uses a proton exchange membrane (PEM) fuel cell to generate hydrogen, then uses a water separator and Pressure Swing Adsorption (PSA) to remove water vapor and purify the hydrogen to 99.99%.
https://www.peakscientific.com/articles ... n-methods/

So far tests have been promising, the generator s running on heavy water and filling the metal hydride cartridges without problem.


Explanation of how the hydrofill works
https://www.youtube.com/watch?v=7tC-uMBQv4g

Hydrofill Pro from ebay, generates 99.99% pure deuterium at up to 3L/h at up to 3MPa(435PSI).
https://www.fuelcellearth.com/fuel-cell ... ofill-pro/
Hydrostik Pro, stores 10L deuterium at 2.8MPa
https://www.fuelcellearth.com/fuel-cell ... ostik-pro/
IMG_20200229_165030702_HDR.jpg
Hydrostik metal hydride cartridge and PEM generator.
IMG_20200229_151334550_HDR.jpg
Water separator.
IMG_20200229_151355999_HDR.jpg
PSA purification column and control board
IMG_20200229_151344515_HDR.jpg
IMG_20200229_151410565_HDR.jpg
Regulator
https://www.fuelcellearth.com/fuel-cell ... regulator/
IMG_20200229_151423038_HDR.jpg
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Rex Allers
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rex Allers » Sun Mar 01, 2020 2:05 am

Good to see someone looking into this D2 generation, storage, and use idea. There was some discussion about this on the forum several years back.

Links to older threads:
Solid state hydrogen storage experiments
Nov 14, 2016
http://www.fusor.net/board/viewtopic.php?f=10&t=11147

Deuterium storage
Dec 21, 2015
http://www.fusor.net/board/viewtopic.php?f=6&t=10517

Back then I began to look into this, accumulated parts and equipment, but as usual, never completed the work.

Today, as I was looking through these threads, I couldn't find anything about one aspect I thought I had shared. Maybe I never did post about it here.

I made my own adapter for connecting a filled cartridge with a valve to open its output. Key starting parts were standard plumbing connection fittings. Then parts were made on a lathe to adapt one fitting into an opening valve for a cartridge.

Here are a few pics of what I made:
full valve-adapter.jpg
full valve-adapter.jpg (29.88 KiB) Viewed 2035 times
valve fittings 2.jpg
made parts dim.png
adapter o-ring.jpg
adapter o-ring.jpg (41.99 KiB) Viewed 2035 times
Need a metal lathe to make the parts. I can share more details if any interest.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman » Sun Mar 01, 2020 3:23 am

Nice work, thanks for the links
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Mark Rowley
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Mark Rowley » Sun Mar 01, 2020 4:59 am

Excellent review Andrew. I saw your FB post about this as well.

About a year ago I spotted a used one on an auction site for about $400...unknown condition or what it's previous life consisted of.

I sure hope the price comes down. $1000 minimum for the works is a pretty penny.

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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rex Allers » Sun Mar 01, 2020 9:31 am

Yikes! Really? I haven't been looking at prices in quite a while.

The Hydrofill I bought in 2015 was about $330 which I thought was pretty steep. So about 3X in 5 years I gather.

Still could be a good deal if a person with a filler would share D2 filled cartridges. I'd think around $100 per might be reasonable, especially without the hassle of trying to get a lecture bottle. The D2 filler owner also gets cheap access to their own virtually unlimited cartridges.

I haven't done the math in a while. Anyone got the number of grams of D2O to fill one cartridge? United Nuclear is selling 100g at $90.

Andrew, let us know if you have success in using a D2 filled cartridge to feed a working fusor run. No reason to think it shouldn't work, but you would be the first to prove it.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman » Sun Mar 01, 2020 4:54 pm

Great work, Andrew.
I think yours is the first report here about actually filling Hydrostiks with D2 from electrolysis.
Using those cartridges for trading deuterium on the street got lots of talk in those older threads by Corby and Rex and me.

A full 10 liters is about 1.65 g of deuterium, requiring 8.25 g of D2O. Depends slightly on the "standard" or "normal" temperature for gas trade by volume, and that depends on the gas being traded.

Cartridge fullness can be determined by weight. Cartridge makers define end of life in terms of reduced H2 capacity at a standard pressure (400 psi) and temperature. Tare is around 90 g for the Brunton branded units we talked about,so we would need centigram scales and reference weights.

The residual quantity of gas that one paid for, left in container at atmospheric pressure, might be relatively less in a metal hydride cartridge than in a lecture bottle. It might not. Has anyone compared the weight of a new (evacuated) cartridge with one that has been filled with H2, then emptied without sucking? The issue came up in previous thread, for purging cartridges previously filled with regular H2.

For today's price of a Hydrofill station, I bet one could get a 1000 liter cylinder of compressed deuterium gas and a regulator with relatively high output pressure. Didn't Corby talk about using compressed H2 for DIY filling of cartridges for some instrument? I bet you can get a cartridge almost half full with only 200 psi, maybe better than that if the cartridge is chilled.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman » Sun Mar 08, 2020 7:26 pm

More updated on the gas handling system progress:

The hydrostik pro was successfully filled with deuterium
IMG_20200229_194837241_HDR.jpg
I bought 1L of heavy water for further experiments
IMG_20200308_144641565_HDR.jpg
New proportional valves for the deuterium pressure control system

The upgraded gas handling system on the Mark III fusor will replace the piezoelectric valve with a proportional solenoid valve. I have tested the clippard valves on my desktop turbo station with air and found them suitable for fine metering, driving them from a dc power supply I was able to control pressure in a conflat cube in the 1-20mTorr range. This type of valve is well suited to connect to an arduino for digital closed loop control. There are 4 valves pictured, 3 from clippard and one from Enfield technologies

The clippard valves:
How to select a valve:
https://www.clippard.com/cms/wiki/clipp ... ction-tips
Flow vs pressure:
https://www.clippard.com/cms/sites/defa ... -Press.jpg
DVP (stainless body) datasheet:
https://www.clippard.com/downloads/PDF_ ... 0Valve.pdf
EVP (nickle plated brass) datasheet:
https://www.clippard.com/downloads/PDF_ ... _Sheet.pdf

The clippard valves have a 0.009" Orifice and a 10v max coil, they require an external driver. This driver could be the EVPD-2:
https://www.clippard.com/cms/wiki/clipp ... lve-driver
or an external driver such as the Adafruit motor control featherwing:
https://www.adafruit.com/product/2927

The valves that I have are the:
P/N: ET-PM-10-0925-V
P/N: ET-P-10-0925-V
P/N: DT-PM-10-010030-V

Enfield valve

Enfield technologies datasheet:
https://www.enfieldtech.com/site/Produc ... asheet.pdf
The enfield valve ($249) that I have (PFV-W24E05-M012C-0200 ) runs on a 24VDC supply, with a 0-5V analog control signal for closed to max flow (the valve has an onboard driver). The valve can also take a >2khz pwm signal from a microcotroller on the analog line. The valve has a 0.12 mm orifice and 0.345 slpm max flow in air at 30psid.
https://www.enfieldtech.com/Products/PF ... ear-Driver
IMG_20200308_144930843_HDR.jpg
Conflat adapter for valve:
IMG_20200308_145022739_HDR.jpg
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman » Mon Mar 09, 2020 11:10 pm

Cost breakdown for metal hydride capture of D2:

Testing conversion efficiency from D20 to D2 captured in metal hydride:
Filling a metal hydride cartridge with 2.04g D2 (11.1L) required 31.7g D2O

1000g D20 costs $1213, so it costs ~$39 to fill a metal hydride cartridge
A hydrostik pro costs $42, and a regulator costs $131
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Richard Hull » Tue Mar 10, 2020 3:40 pm

Thanks for costing this out once the process gets rolling. The intial outlay on the hydrolizer is?
The cost of $1.00/gram of D20 is not bad.

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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman » Wed Mar 11, 2020 3:31 pm

Yes, good to see practical cost numbers. $3.50 per liter is cheaper than xenon!

It's intriguing that you got substantially more than 10 liters into a cartridge.
Maybe the hydrostik nominal capacity is derated a bit to allow for wear, like the capacity of electric car batteries.
Or the storage medium accomodates D2 better then H2.

Getting 11.1 l of D2 from 31.7 g of heavy water implies that your whole kilogram would yield 350 liters.
According to catalog at Cambridge Isotopes, you can get 500 liters of compressed D2 gas for the same money.
d2_gas.png
d2_gas.png (47.41 KiB) Viewed 1569 times
.
We might get 80% of the 500 liters to flow from cylinder into hydrostiks at 400 psi.

I think one benefit of electrolysis at home is no hazmat or freight shipping issues.
Same can apply to using deuterostiks at home, if some enthusiast starts a filling service.
Can items be listed on ebay with a price that includes refundable core fee? :-)
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