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Direct Methanol Fuel Cell Project.

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Patrick

Fri Jan 20 2017, 11:26AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Platinum Ruthenium and Platinum black, 5 layer MEA.

I meant to put this in the general science forum. can it be moved mods ?

Bjørn

Fri Jan 20 2017, 01:06PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Moved

2Spoons

Fri Jan 20 2017, 09:30PM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615

Will be watching this one with interest. What did that cost you?

Patrick

Fri Jan 20 2017, 09:46PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

2Spoons wrote ...

Will be watching this one with interest. What did that cost you?

59 US$ , 4mg/cm^2 Platinum/Ruthenium and 4mg/cm^2 Platinum/Carbon on the other side. 2.2 cm square, 5cm^2 active area with 10cm N117 Nafion membrane around the edge.

PLA and ABS are destroyed by methanol. So that rules out my 3d printer.

i bought such a small one due to my fear of catalyst poisoning.

im still trying to figure out how the catalyst loading affects current and surface area. they offer 0.03mg up to 4mg, per cm^2 which is big in cost.

I think the anode is the Pt/Ru (fuel) side from here:

The cathode side is the oxidizer and Pt/Carbon side.

Im having a hard time getting datasheets of any kind from the company, despite having purchased a product and many emails. thats making me mad.

Im also not sure how to seal the Nafion sides in a leak proof way, im not sure if silicone adhesive would work. the "thiol-group" based epoxies are totally ruled out, as fuel cell PEMs of all types are massacred by the tiniest of sulfur presence.

Carbon_Rod

Wed Jan 25 2017, 06:31PM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

Regular cheap Delrin works around most Alcohols including Methanol.
Milling machines cut Acetal Plastics with ease, and o-ring seal channels are easy to route out (follow the manufacturers specs, as most failures are from engineers trying to guess the seal tolerances).

Note that some silicone based stuff may not be Methanol friendly, so carefully check the documentation of whatever adhesives are around.

Conundrum

Thu Jan 26 2017, 08:08AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059

Absolutely fascinating, thanks for sharing.
Going to forward this to Jim, Adrian and Marcel at the Digital Greenhouse as this might well be a potential application for 3-D milling machines.

A little tip, the infamous "black plastic" unrecyclable food containers might be a good starting point.
From experience a simple test for sulphur is to put a prepared piece of copper PCB on the surface to be tested and heat it up, a change from copper colour to black in a few minutes would show that the material is contaminated.
Works for me with Cu + elemental sulphur even in a domestic oven at 55C.

Also worth noting, anything made of rubber would be out as vulcanization uses sulphur so this would be a bad idea.
I wonder if the damage is reversible and anything to do with sulphide formation, if so then there might be a way to repair damaged PEMs with sulphur poisoning using a similar mechanism to desulphating lead acid cells?

Patrick

Fri Jan 27 2017, 11:17AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ive been assured theyre getting the datasheets together. My 0.002 inch thick stainless steel foil has arrived its #309 and the 300 family does well against methanol. ive been trying to polyurethane and aluminum mold form patterns using a 60 ton press so we'll so. other up dates to follow.

After a long call with an expert.

-distilled water and DI water are best to control molarity.
-Ions in water (Cu, Fe, S) or dissolved from plumbing within the fuel cell are poisonous. Stainless solves this.
-even then the super-acid Nafion membrane will react and degrade stainless steel over 10-30k hours. coatings are often used.
-350mA per cm^2 is more attainable.
-Nylon and Teflon are good choices.
-low pressure drop and molar concentration are important to over all balance of plant and fast response to load changes.

im still tring to figure out a good parallel flow tube field where each parallel tube is fed evenly and some dont hog more fluid than others.

Conundrum

Sat Jan 28 2017, 07:44AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059

Um.. what you need then is the water equivalent of a constant current.

Patrick

Sat Jan 28 2017, 08:52AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

I think the pump was an oversight on my part.

Aluminum, copper, unknown steel and plastic, sigh.

i think its on to the peristaltic pump type.

hen918

Sat Jan 28 2017, 11:19AM

Registered Member #11591 Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556

Patrick wrote ...

I think the pump was an oversight on my part.

....

Aluminum, copper, unknown steel and plastic, sigh.

i think its on to the peristaltic pump type.

it looks like a little gear pump to me.
A peristaltic pump has one continuous flexible tube (sometimes the same tube that supplies it), a cam flattens the tube turns, forcing the liquid through the pump.
A peristaltic pump would be better for lower contaminants, but would probably have a lower flow.

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