Hey! So I noticed that producing oxygen and hydrogen gas from water is as easy as running current through water (with an electrolyte mixed in)! I was wondering if anyone liked the idea of producing a small fuel cell for demonstration’s sake? Just thought it’d be kinda cool!
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I think @PearceDunlap or @lukeiamyourfather was building one. My brain falters in remembering who was doing it.
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I worked for a couple years at United Technologies Power (Fuel Cell Division, all fuel cells on the Space Shuttles were built/refurbished after every flight by them)… They generated hydrogen by cracking methane into Carbon and Hydrogen. The H2 used in a proton membrane exchange fuel cell. During the reformation process, the heat from cracking was recovered as well as burning the CO to get CO2. Other by-products like NH4 (ammonia) and N02 (nitrous oxide) were run through catalyst beds or ionized filter beds to extract those so that emissions would met California Cat 4 level emissions requirements (no small trick).
They had some test vehicles: Buses, some cars (a Nissan as I recall), plus a they built some units for submarines in lieu of batteries. But the stationary power units were the primary commercial products.
Because we used the “waste heat” to either generate hot water or heating for building or in the summer rum micro=turbines for refrigerant we were able to achieve up to 96% BTU efficiency between the electricity, heat and cooling. The new World trade towers have seven 400KW fuel cells each as back up power and run continuously. The police station in Central Park also uses Fuel Cell that is design wise the same, but only 200KW (2 X 1200VDC-100KW fuel cell stacks).
I’d love to help or contribute in how I can. My be able to contact some engineers I worked with that might be willing to give some guidance or not (I never signed so many NDA’s in my life). There are lots of types of fuel cells, I’m really only familiar with the Proton Exchange Membrane type. There are some other really high temperature types (ours was only 425F, any higher and the Teflon would break down) that produce a higher percentage of of electricity, but are much more difficult to operate.
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Cool! Didn’t realize the cells got so hot… To be sure, there will be some less-than-NASA grade parts used in the build. For instance, the electrolyzer would just be a 9 volt battery, some electrolyte, graphite rods, and a few inert tubes for collection. There is still plenty to learn about the topic before I consider how it will impact my budget! Should probably start by examining the types…
Anyway, where did the nitrogen for ammonia, no2 come from? Is that entirely unavoidable, even for a small, likely inefficient, cell?
I’m also assuming I can make a cell that doesn’t weigh over 30 lbs, as it would have to be moved on request. The idea isn’t to supply power for the space at the moment, just to show that a small fuel cell can be done reasonably. Any obvious problems for a tiny fuel cell?
I would have liked to use a viewing port to show the innards of the cell as it worked. But as I recall, the inside of a fuel cell can be very acidic. Do you think a viewing port could work?
I built one and have spare parts to build more if you’re interested. It’s similar to this one. It works pretty good for what it is.
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Okay, here goes in simple terms. Natural gas is the power source and both burned and “cracked” into free Nitrogen (N) and Carbon © along with atmospheric air - which for our purposes is Oxygen (O) and Nitrogen (N).
The heat generated during all of the following processes gets used 7 times and goes through 6 or 7 heat exchangers. The heat is reused a number of times.
Natural Gas/Methane is CH4, some of this is burned with air O & N, the rest of the CH4 is “cracked” into C & H. In the Reformer some of the natural gas is burned to produce a high temperature for platinum catalyst bed (a 400KW Fuel Cell the Reformer uses about 100 troy ounces of platinum) to react with the CH4 and a high temperature catalyst bed “cracks” the CH4 into C and H. The burning process produces (from air injected into the Reformer, air has Oxygen and Nitrogen) H2O, CO (incomplete combustion just like your car does) CO2, NO2 and free H.
And just like your car has a catalytic converter so does the Fuel Cell. It resues the heat in a different catalyst bed and “cracks” the NO2 into N and O, the O combines/burns with the C from the Methane to produce CO2 (and more heat), the H goes to the fuel cell proton membrane exchange which combines with the O in the air to produce H2O - water. Mean while, the Reformer is taking the N recombining some of it with the free H to produce NH3 - otherwise known as Ammonia. This is a pollutant, so it is run through a fluidized bed of water, ammonia is highly soluble in water, the water is circulated through another ionized bed similar to a water softer, just different type pellets inside and the NH3 is extracted.
The CO - carbon monoxide, is burned inside the reformer combining with O from the air until it is also CO2. So what comes out of the Fuel Cell exhaust is H2O (from fuel cells) and CO2 and some H2O from the reformer. All the other nasties are converted into something less nasty, compact, and captured.
The the stationary fuel I just described weighs about 60,000 pounds, is 8.5 feet wide, and when on a double drop bottom trailer does not require a permit to transport to it’s site. There are 4 X 1200VDC/100KW stacks for a total output of 400KW. It can connect to the grid to sell back unused power. All the heat generated is used for heating or cooling.
Really pretty simple - wished I’d paid more attention in chemistry.
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Add-on to the above: this is what the Fuel Cell I described looks like without the case. Seven Modules (Housing not shown and ESM is actually two separate functions housed together), I was QE responsible for two of the modules: FPS and the ESM (I hope the irony of me assigned to Electrical System Module is apparent. Lots of learning took place after hours.)
The PSS is te actual Fuel Cells, the rest is to support it running. The Fuel Cell Stacks were about 8 ft tall.
I have to mention this here, Did y al know that jewlery now has a hydor
torch? no fuel, just distilled water
They’ve had it for some time now, very nice tool.
It’s big advantage is s very hot flame, with standard MAPP torches significantly. Varies between 4000F and 5100F under ideal conditions. I’d guess the temp can be adjusted some where between the two. Musch hotter than MAPP w/o O2 injected into the mix.
The maximum temperature of about 2,800 °C (5,100 °F) is achieved with an exact stoichiometric mixture, about 700 °C (1,300 °F) hotter than a hydrogen flame in air. from wiki
It is a really neat tool
Looks like a pretty heavy-duty affair!
I’m currently reading through http://www.pragma-industries.com/technology/fuel-cell-explained/ in addition to your comments to get an idea of whether the project would be safe to do, even if on a much smaller scale.
Thanks for the input! Definitely a project that will require a great deal of forethought!
http://makezine.com/2008/02/29/how-to-build-your-own-ban/ designing something like this would (hopefully) be within my abilities, with a small electrolyzer that outputs gaseous hydrogen and oxygen separately as a fuel supply. Ofc from there I might have gained enough experience to be a little more ambitious with it!
I know how the PEM type works, worked around the assembly area on individual cells and stacks but directly on them. I worked on getting the H2 to the FC and managing the power that came out.
There were some experimental units that lacked reformers that were on pig farmers that captured methane for some 250kW units. They used bio-mass but were incredibly unreliable and required lots on scrubbers for both water and lots of ammonia. Never actually saw one, but heard discussions on getting them to work.