PEM fuel cell deuterium generator

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Richard Hull
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Re: PEM fuel cell deuterium generator

Post by Richard Hull »

Just a thought related to Jim's overpressure comment on the PEM cell's membrane. Maybe Mark Rowley might speak to this idea.

Would a syringe on the O2 side help to balance or lessen that pressure differential during operation?? it might need to be a bigger syringe volume for O2

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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russssellcrow
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Re: PEM fuel cell deuterium generator

Post by russssellcrow »

Hey Dennis, thanks for the feedback! Since everyone here comes from a disimmilar background, it is useful for the group.

I think you understand that a mass flow controller (MFC) is a mass control valve, it regulates admittance of D2 gas to the chamber. This is understood.

As to the whole Arduino scene, this changes everything. Arduino has layed open computer control to the masses. Where we used to control systems with FPGAs, ASICS, or RTOS (Google this), everyone can now code a program (or download it) and run just about anything they want.

In your interest, I shall label the pics in a future post. The adaptation of existing hardware is rather clever...

As to why we go to all this trouble to freeze Deuterium Oxide; when you electrolyze D20 across a Proton Exchange Membrane (PEM), the membrane doesn't prevent Heavy Water from evaporating across the membrane. We are condensing the Heavy Water from the D2 stream, and recovering most anything which leaks. So far we collecting about 3% of the D2O which is electrolyzed.

I shall post the schematics and code into the Control & Instrumentation section soon.
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russssellcrow
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Re: PEM fuel cell deuterium generator

Post by russssellcrow »

As per Dennis request, I diagrammed the PEM Electrolyzer Dryer, and included my notebook schematics (which are mostly current). I'll post the Arduino Code in the Control and Instrumentation directory, should anyone want to utilize it.
PEM_Electronics_BlockDiagram.jpg
The PEM cell is driven in Delta Sigma timebased pulses, determined by the User setting on the Web page. How do you get the Web page?
1. Enter your Wifi's Name and Password in the header of the Arduino Code, then compile and upload it to the Heltec, it will attempt to attach on Boot Up.
2. When the Heltec attaches, it will display the IP Address it has been assigned by the DHCP of your WiFi Router.
3. Use this Address to access the Heltec's Web page in most browser's address bar at the top: i.e. \\192.168.1.137

The following is the schematic. The N-chan MOSFETs you use need to be rated for 10Amps and >50V. IRF520 will work fine, so will many others you may have laying about. Opto Isolators are pretty universal too as long as they have Darlington or MOSFET outputs they should work.
PEM_Electrolyzer_Dryer_Schematic.jpg
These are the labelled pics of the PEM Electrolyzer. Dennis asked how I know it's making Deuterium, you test it with Water first. The Hydrogen stinks and the Oxygen smells sweet (also the ports and polarities are marked, it's hard to get wrong) I changed the plumbing of the bottom ports of the PEM cell, so we can fill both sides from 1 port and have a shutoff valve.
PEM_Electrolyzer_Dryer_front.jpg
PEM_Electrolyzer_Dryer_rear.jpg
Operation is pretty easy:
1. Fill the PEM with D2O, and push a little extra so it just barely shows in the O2 and H2 vent ports. When you start the process, this will push a small Marker Bubble up the lines so you can see the flow rate. It also makes a liquid wall to keep the Deuterium Gas from being mixed with the air in the system. Don't worry about the bubble, it will drop into the trap at the 1st filter vessel for capture.
2. Use the Web page to drive the Chiller through the dual Peltier Controls. We found that about 10 on each Setting will take the Chiller cube down to where it frosts on the outside. If you overdrive the Peltiers, the Chiller can go to -60'C which is way too cold.
3. Next start the PEM cell on the Web page. A Setting of about 12-15 here will make your D2O bubble move along pretty well toward the filters, about 1 inch/5 seconds. 2 inches of 4mm tubing full of Deuterium (6.28 mm^3) at Standard Atmospheric pressure is enough fill ~150cc at 30 microns.
4. We ran the Fusor vaccum until we hit <5 microns of pressure, and then actuated the Mass Flow Controller, MFC (another post yet to come, with schematics and code). Then we balanced the pressure to 30 microns using the MFC Web page, with a setting of about 25%.

We still have a lot of work to do to go operational. We have begun work on Fusor #2, because it's time to light this thing up for real, but that is a different post.
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Richard Hull
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Re: PEM fuel cell deuterium generator

Post by Richard Hull »

Elaborate in the extreme, for sure. As long as you have heavy water, you have flawlessly clean, dry and pure D2 for fusion. Great work!

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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russssellcrow
Posts: 68
Joined: Fri Dec 27, 2019 12:40 am
Real name: Russell Crow
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Re: PEM fuel cell deuterium generator

Post by russssellcrow »

Elaborate...looks pretty straightforward, you wouldn't believe some of the hoops I jump through in my day job.

But seriously, the issue you brought up with overpressuring the PEM membrane in this cell is real. On this cheap PEM cell, I would wager that the membrane can't push more than 1/2 Bar, with that comes heavy water vapor and Oxygen in the D2 stream. By comparison a Plug Power Cell can push about 10 Bar of differential pressure. Since the membrane is very critical to isolation, the next upgrade to this component will be the PEM cell.

In the meantime, we have decided it is time to take heed to your warning and build a serious Fusor. We've seen what we needed to in our see through filter cylinder (I just inherited it), and started collecting some serious hardware. See the post titled Fusor2_DMS, this is getting so much better!
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