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

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

Post by Andrew Seltzman »

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

Post by Rex Allers »

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
viewtopic.php?f=10&t=11147

Deuterium storage
Dec 21, 2015
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
valve fittings 2.jpg
made parts dim.png
adapter o-ring.jpg
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 »

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

Post by Mark Rowley »

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 »

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 »

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 »

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 »

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 »

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 »

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

Post by Andrew Seltzman »

I tested the fusor with the deuterium from the metal hydride cartridge and found equivalent performance to the deuterium from the lecture bottle. Due to some arcing from a damaged grid insulator, voltage was limited to 30kV. A run with a deuterium lecture bottle was followed by a run with the metal hydride cartridge, which was followed by another run with the lecture bottle. Purging of the fuel lines brought the core up to a few torr of air, followed by a few torr of D2 between each run.

Run parameters for both runs were:
30kV, 17.4mA, 10mTorr, ~200k n/s

So that's a confirmation that it will work.

Lecture bottle and metal hydride cartridge
IMG_20200311_223453589.jpg
lose up of metal hydride cartridge, regulator, and connection to piezo valve
IMG_20200311_223505220.jpg
Star mode with metal hydride cartridge
IMG_20200311_223733286.jpg
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman »

That is really cool, Andrew. Hip, hip, hooray!

Might well be a "first time in the world" demonstration, without needing many words of qualification.

Confirms that gas dry enough to put into hydride cartridges is dry enough for fusing.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

I recently dismantled one of the used metal hydride cartidges that would no longer take a charge.

The top screws on, though I was unable to find a way to unscrew it, it may be epoxied in place
IMG_20200312_223728291.jpg
There are threads on the ID of the cylinder
hydrostick1.jpg
Cutting the cylinder with a tube cutter removed the top. It is filled with loose powder
IMG_20200313_114639214.jpg
The casing is pretty thick, about 1/8"
IMG_20200313_114724975.jpg
The cap contains a filter assembly to prevent powder from getting out, and a valve that is opened by depressing the pin
IMG_20200313_114643311.jpg
XRF analysis on the powder indicated it's composition by mass is
70.9% Ni
21.1% La
6.92% Ce
0.42% Cr
0.68% Mn

The powder is almost certainly Lanthanum pentanickel (LaNi5), a common AB5 metal hydride for hydrogen storage. The other elements are likely impurities, probably reflecting the low cost compared to commercial reagent grade LaNi5, though it obviously doesn't seem to affect storage.
https://www.sigmaaldrich.com/catalog/pr ... &region=US
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rex Allers »

Great stuff Andrew. Thanks for taking it all the way to fusion and sharing the results.

Good info (with resources not available to many) on what is inside too.
You said, "one of the used metal hydride cartidges that would no longer take a charge."

Any idea why it wouldn't take a charge?
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

It was a used one that I got on ebay with a Brunton Reactor fuel cell. It was left screwed into the fuel cell for probably long after it was empty and air with moisture likely got in (by permeating through the fuel cell membrane after there was no flow of hydrogen out of the cartridge) and destroyed the metal hydride.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman »

Fascinating. Probably not good stuff to eat or get in your eye! Nice that you identified it as a standard formulation. Online searches for charge/discharge pressure curves etc. need not be limited to Hydrostik brand.

Andrew, would you be interested in helping to answer an old question, by doing one more "assay by fusor"?

Right here is one Brunton core that was bought new, a few years ago, and run to shut-down in a fuel cell while ampere hours were logged. Then immediately disconnected, and stored clean and dry with whatever residual hydrogen is left in it.
If you have no such thing on hand, you can have mine as a gift. Hope you can then repeat your fill-and-fuse exercise, with no special effort to purge the regular H2.
Neutron yields in a stable system are easier to measure than H2/D2 ratios (and more relevant), for those of us without mass spectrometers.

p.s. Harold Urey's discovery of deuterium used a high-resolution optical spectrometer. But he had to do a lot of enriching, by letting LH2 boil down, before there was enough D to detect that way. First trial failed because the H2 was prepared by electrolysis, and was deuterium-depleted to begin with!
Mass spectrometry had been developed, and had already measured the stable isotopes of all other light elements. But deuterium was hiding behind molecular ion H2+ in the mass 2 channel. Soon after Urey's report, deuterium in enriched samples was confirmed in the mass 3 channel, as HD+. There ought to be no such problem using a mass spec. to measure H contamination in D.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

No special method to purge the residual hydrogen was used on my metal hydride cartridges. They were emptied of H2 down to atmospheric pressure then filled with D2. The H2 to D2 ratio would probably be a few ml H2 per 11L D2.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by ian_krase »

Beware -- hydrogen storage material is sometimes pyrophoric!
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman »

Andrew, thanks for response about the residual hydrogen question. Back in 2016, technical sales told us that unlike the Brunton cores, new Hydrostiks came evacuated. That suggested no extractable hydrogen, or even argon/nitrogen from the factory atmosphere, and that a new cartridge would weigh more after filling and then emptying to 0 psig. Have you heard or found otherwise?

Am still having trouble making sense of this chart, from a European maker (or seller) of hydrogen storage cartridges:
https://www.pragma-industries.com/broch ... -V2019.pdf
hydrides2.png
hydrides2.png (138.88 KiB) Viewed 54389 times
Perhaps very generic, and old, but it seems to show most of the hydrogen locked up at 1 bar! Maybe something was lost in translation.
For material comparisons, one would think the capacity at some stated (or conventional) absolute P_min is just as important as the capacity at P_max.

Andrew, it was insightful to show us the Sigma Aldrich unit prices for hydrogen storage media,
which (in 10g quantities) are many times the retail price of whole Hydrostiks or Hydrocores.

Online documentation taught me some things about Hydrostik and Hydrostik Pro.
The latter supports faster charging and discharging, "for educational applications", using a different storage medium.
The former uses a TiMn2 formula according to one document, and an "AB5" according to another. https://www.horizonfuelcell.com/minipak

Did the non-Pro Hydrostik and Hydrofill get discontinued, or just re-named and labeled?
Hard to find non-Pro stuff online today, except that minipak brochure and this old Hydrofill manual (version 13 :
resources.arcolaenergy.com/docs/Manuals/HYDROFILL_Manual_V13.pdf

One paper lists a bunch of LaNi5 variants, with other elements replacing some of the nickel. They don't show the ceriated flavor that you found.
hydrides.png
from fcto_h2_storage_summit_motyka.pdf

Can't find the documentation from an instrument maker whose hydrogen storage medium is/was depleted uranium powder.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

I think the non pro versions were discontinued.
The one I took apart was the brunton hydrocore (a rebranded hydrostick pro).
Both the Brunton hydrocore, and the hydrostik pro version come full with hydrogen.

Depleated uranium is usually only used for storing tritium. It has to be heated to several hundred C to release the tritium which gives a level of protection against accidental release if the canister is damaged since it will not desorb unless heated.
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

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? - Rich Feldman
Would anyone be interested in purchasing D2 filled cartridges for the following cost + shipping
Filled Brunton Hydrocore / Horizon Hydrostik PRO cartridge containing ~2g (~11L) of D2 = $115
Cartridge refill for ~2g (~11L) of D2 = $65
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Rich Feldman »

I would go for that.
But promised myself not to work on deuterium before I have an operating vacuum chamber again.

Cartridge connectors and pressure regulators are easy to get on ebay, but I would first look into hacking the Brunton fuel cell unit on hand.
viewtopic.php?f=10&t=11147&p=73509&hili ... ted#p73509
DSCN0059.JPG
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Andrew Seltzman »

Recently did some more development on the proportional valve pressure controller. I have the proportional solenoid valve working open loop with both air and hydrogen with very promising results. The drift is less than the piezo valves I was using previously, and they don't require a high voltage source. The end goal is to have an arduino controller query the presser over an rs-485 connection to the vacuum gauge and run a digital PID control loop to stabilize pressure.

This was using the clippard ET-PM-10-0925-V proportional valve $67 ea from http://www.gocfa.com
https://www.clippard.com/part/ET-PM-10-0925-V
and the EVPD-2 valve controller $276 from clippard, however any current driver will work (or voltage source if you are willing to accept a slightly non-linear response)
https://clippard.com/part/EVPD-2

Ion source testbed mounted on dry turbo station
testbed.png
MKS 901p piezo/pirani gauge
vacuum gauge.png
Clippard valve mounted on 1.33CF flange
valve.png
valve controller, taking a 0-5v analog input signal
controller.png
pressure when stepping input voltage to controller
pressure.png
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Re: Mark III Advanced Pressure Control / Deuterium Generation from D2O / Metal Hydride Storage

Post by Richard Hull »

Andrew, a plus-ultra setup! Very nice indeed. Nice plot on pressure as well. Were those wide ranging pressure regimes under you new control setup? We look forward to future posts on this system.

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

Post by Andrew Seltzman »

plots are for open loop control of the valve stepping through different input voltages on the driver.

latest tests using a Recom RCD-24-0.30/W/VREF LED constant current driver ($18) to run the valve instead of the more expensive Clippard EVPD-2 driver.
https://www.digikey.com/en/products/det ... EF/2612667
you can also get them as free samples:
https://recom-power.com/en/rec-s-RCD-24.html?0

The LED driver does not have the scaling functions that the clippard driver has so the programming voltage to the driver to command pressured between 1-10mtorr is only a several hundredths of a volt wide, id does work as a valve driver though, at much lower cost. The clippard driver does work better out of the box, but the led driver certainly could have an op-amp or resistor scaling network put before the input.
recom-led-driver.png
recom led.png
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