Trying to define terms for hydrogen fuel technology

[Blueshift]

Hi all every time I look up Hydrogen fuel or Hydrogen fuel cell i only get the videos etc of the contraptions that produce the hydrogen from water. I am looking for the specific name of the device that turns the hydrogen into electricity. perhaps someone could help me.

1. what is the device called that produces electricity from hydrogen?

2. what is the device called that extracts the hydrogen from the water?

Thanks in Advance.

 

[spinningmagnets]

A Proton-Exchange-Membrane (PEM) is a type of "fuel cell". It takes a hydrogen and strips the electrons off of it, so there is no combustion. Gaseous hydrogen is not very dense, so a vehicle that uses a hydrogen fuel cell will often use a device called a "reformer" which takes heat to strip the hydrogen off of a fuel. The smaller the molecule, the lower the temperature needed to get the hydrogen, so a popular dense liquid fuel is methanol.

One way to separate the hydrogen and oxygen that makes up the H2O of water, is to simply run electricity through it with an electrolyzer (electrolytic cell). 12-volts is all you need. Oxygen will bubble up off of one electrode, and hydrogen will bubble up off the other. The oxygen will make a match flame flare up bigger, and the hydrogen will make a pop (only sample a small amount with a match). The process is very inefficient, unless you make hydrogen with a home-made wind-generator. Hydrogen will seep out of a steel tanks walls (because the molecule is so small), and it will cause an embrittlement of the metal.

 

[bigmoose]

SpinningMagnets gave you one type of fuel cell. Also look up solid oxide fuel cell. It is the other variant that does not use platinum, but uses rare earth materials and ceramics. It is also more sulfur tolerant. They have a drawback however, as being a big ceramic stack, they do not like to be thermally cycled or power pulsed. They like a slow turn on, then steady power production, then a slow cool down. Neat device however.

 

[Blueshift]

Thanks for your responses. That helps explain things. So the front of this bicycle is a pem fuel cell?
http://www.youtube.com/watch?v=THZ-HReaj8U

 

[spinningmagnets]

It probably is. It sounded like the white cylinder at the rear was dry compressed H2 for the fuel. Range will be short, but there have been enough of these type of demonstration prototypes that the technology clearly works. I didn't know anyone was making fuel cells this small, it would be fun for experimentors to have these available to play with.

Right now, most dry compressed commercial H2 is made by stripping it off of methane (natural gas).

Here is an article about Stephen Friend and his home on Stuart Island. It is a working system that generates his own H2 and uses a fuel cell to make his own electricity as needed. http://www.hfcletter.com/issues/XXII_9/stories/978-1.html

 

[bigmoose]

I toured a few plants that were in the fuel cell development business back "in the day..." Before folks get carried away with the concept. 1) There is only so much platinum available, and it isn't enough to replace the transportation load in KWh with proton exchange fuel cells. This drove my interest in solid oxide fuel cells for base load, as they were not so limited. Although they did have a propensity for rare earth elements. The big thing to me, that was a deal killer, was standing next to the nice microwave oven size 5 KW fuel cell that was operating quite nicely; but attached to a 20 ft. long (~7 meter) semi trailer containing the "balance of plant" as in the reformer necessary to deal with fuel oil to get to a suitable intake fuel. The natural gas balance of plant was much smaller, and about the size of 2 or 3 microwaves.

 

[spinningmagnets]

Thanks, Bigmoose! I only have a passing conversational interest in fuel cells. The people who are promoting fuel cells rarely spell out what the bottlnecks are.

 

[Maxrevs]

Hi Blueshift,

I'm a development engineer working in the fuel cell industry... I'm probably way too late, but please feel free to ask way with any FC related questions.


1. what is the device called that produces electricity from hydrogen?
The macro name is the stack... comprising of usually a few dozen to several hundred unit cells. The business end is the CCM (catalyst coated membrane, one CCM per unit cell). CCM is the expensive bit, containing platinum as the Catalyst.

2. what is the device called that extracts the hydrogen from the water?
The precess is called electrolysis, however almost all hydrogen today is produced from reformation of natural gas. There are some other methods on the radar like photocatylic and biohydrogen, but realistically, none of these are going to scale anytime soon to replace Fossil Fuel.

Cheers,

Max