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PostPosted: Jan 08, 2014 4:20 pm 
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I skimmed Cyril R's PDF on PEM and SOFC fuel cell costs. I noted that they talk about the cost of fuel cells. The SOFC fuel cells that they are talking about are based on the type of technology that Bloom Energy uses. Redox Power claims that they have a much better electrolyte that can run a t 650C instead of 900C. This makes the materials problems much easier and thus lower cost. They see a path to 300C which would let them use things like stainless steal. Also they claim power densities of 2000 mW/cm instead of 291 mW/cm. This is supposed to get the cost down to $1000/kW instead of the $6000/kW quoted in the PDF. They are supposed to start shipping by the end of 2014 so we will see if their claims are true.

Another article on their technology is at http://mtech.umd.edu/news/press_release ... cells.html


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PostPosted: Jan 08, 2014 4:27 pm 
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I feel a bit guilty about continuing this off-topic subject, so I will try to get back to LFTRs. If this distributed fuel cell thing works out can't we replace natural gas with Hydrogen by using the high temperature heat generated by a LFTR? We could run out of natural gas, but Thorium should last a long time. 8)


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PostPosted: Jan 08, 2014 4:58 pm 
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Tim Flavin wrote:
I skimmed Cyril R's PDF on PEM and SOFC fuel cell costs. I noted that they talk about the cost of fuel cells. The SOFC fuel cells that they are talking about are based on the type of technology that Bloom Energy uses. Redox Power claims that they have a much better electrolyte that can run a t 650C instead of 900C. This makes the materials problems much easier and thus lower cost. They see a path to 300C which would let them use things like stainless steal. Also they claim power densities of 2000 mW/cm instead of 291 mW/cm. This is supposed to get the cost down to $1000/kW instead of the $6000/kW quoted in the PDF. They are supposed to start shipping by the end of 2014 so we will see if their claims are true.

Another article on their technology is at http://mtech.umd.edu/news/press_release ... cells.html


This is clearly the way forward for fuel cells; greatly increasing the power density with more reasonable operating temperatures.

This company makes some impressive claims:

http://www.redoxpowersystems.com/wp-con ... -935-9.pdf


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PostPosted: Jan 08, 2014 5:06 pm 
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DaveMart wrote:

I was pointing out that should PEM fuel cells reach mass production for automative purposes then they would have a cost advantage against alternatives.


Highly questionable. PEMFC requires hydrogen or onboard reforming; both are nonstarters.

SOFCs are far more interesting as you can run them on hydrocarbon fuels. Possibly even diesel now that you have ultra low sulphur diesels. Its too bad they are less suitable, due to the high temperature thin membranes, for automotive application. It is hardly an interesting market though, as I was pointing out, but you seem to have missed that point.

SOFC running on natural gas a $500/kWe for a stationairy application cogeneration and even peaking power is very attractive and practical.

PEMFC in mobile application running on hydrogen at $500/kWe is completely uneconomic and impractical. Natural gas powered ICE cars aren't catching on much, for reasons that are greatly amplified with hydrogen PEMFCVs.


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PostPosted: Jan 08, 2014 6:26 pm 
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Quote:
Highly questionable. PEMFC requires hydrogen or onboard reforming; both are nonstarters.


Non-starters?
They are already building them, both for the home and cars.
In the hundreds presently, but rapidly ramping to thousands pa.

On board reforming is not on the present technological agenda, but reforming works fine in the home, and CF tanks do the job of storing hydrogen in a car.

How you can call technology in production a non-starter is baffling.


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PostPosted: Jan 08, 2014 7:12 pm 
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DaveMart wrote:
Quote:
Highly questionable. PEMFC requires hydrogen or onboard reforming; both are nonstarters.


Non-starters?
They are already building them, both for the home and cars.
In the hundreds presently, but rapidly ramping to thousands pa.

On board reforming is not on the present technological agenda, but reforming works fine in the home, and CF tanks do the job of storing hydrogen in a car.

How you can call technology in production a non-starter is baffling.


Not baffling at all, natural gas vehicles are in production, with about 15 million driving about according to the Wiki:

http://en.wikipedia.org/wiki/Natural_gas_vehicle

Yet, out of roughly a billion motor vehicles, that's 1.5% market share. These vehicles have been on the market, in production, for a long time, and natural gas, unlike hydrogen, is one of the major fuels that has been available for decades, and using cheap internal combustion engines and cheaper storage tanks than hydrogen tanks.

So they are nonstarters as well; HFCVs amplify the nonstarting attributes.


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PostPosted: Jan 09, 2014 12:30 pm 
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Asserting something is so is not debate without consideration of the evidence.

Toyota has around 500 engineers, many from the team that gave us the Prius, working on PEM fuel cells.
Hyundai, Daimler and others also have major efforts in the field and the collective effort amounts to billions.

Your take on it is at wild variance with the DOE, and I could cite umpteen studies from them to that effect.

As for home fuel cells, to name just one major company building PEM fuel cells, we have Panasonic.

And you think that it is in some way reasonable just to pronounce that none of that will work.

I thought it was the renewables everywhere crowd that went in for that sort of fluff.

I was hoping for a reasoned discussion.

I can find nothing rational in your wilful dismissal of all the work in the field, presumably not on the basis of any relevant qualifications at all.


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PostPosted: Jan 09, 2014 1:03 pm 
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As a chemist I have studied with numerous people who have since done actual research in the field.

Compact reformers that actually work properly, are resistant to shock and prevent enormous CO contamination which will kill PEM membranes if not careful are proving far more difficult to engineer than was originally projected.


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PostPosted: Jan 10, 2014 5:42 am 
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DaveMart wrote:
Asserting something is so is not debate without consideration of the evidence.

Toyota has around 500 engineers, many from the team that gave us the Prius, working on PEM fuel cells.
Hyundai, Daimler and others also have major efforts in the field and the collective effort amounts to billions.

Your take on it is at wild variance with the DOE, and I could cite umpteen studies from them to that effect.

As for home fuel cells, to name just one major company building PEM fuel cells, we have Panasonic.

And you think that it is in some way reasonable just to pronounce that none of that will work.

I thought it was the renewables everywhere crowd that went in for that sort of fluff.

I was hoping for a reasoned discussion.

I can find nothing rational in your wilful dismissal of all the work in the field, presumably not on the basis of any relevant qualifications at all.


My goodness!!! I've made none of those claims for which you accuse me.

Shame on you, kettle black!


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PostPosted: Jan 10, 2014 11:50 am 
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E Ireland wrote:
As a chemist I have studied with numerous people who have since done actual research in the field.

Compact reformers that actually work properly, are resistant to shock and prevent enormous CO contamination which will kill PEM membranes if not careful are proving far more difficult to engineer than was originally projected.


Good. Could you tell me more about these devices? Are they low maintenance, what is the efficiency, what is the unit price for a (say) 100 kJ/s H2 output reformer?


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PostPosted: Jan 10, 2014 1:17 pm 
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You need a CO scrubber which normally means you have to force the hydrogen through a membrane.

I have seen work that combines the membrane extraction and the forming catalyst in a single frame in an attempt to increase efficiency by forcing CO back into the reformer.

As to cost, it is hard to say at this point but it is safe to say they don't really like vibration.


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PostPosted: Jan 10, 2014 1:21 pm 
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E Ireland wrote:
You need a CO scrubber which normally means you have to force the hydrogen through a membrane.

I have seen work that combines the membrane extraction and the forming catalyst in a single frame in an attempt to increase efficiency by forcing CO back into the reformer.

As to cost, it is hard to say at this point but it is safe to say they don't really like vibration.


So if they don't like vibration, how does that match to your claim of them being robust?

What does a 1 kg/h H2 reformer cost?


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PostPosted: Jan 10, 2014 1:34 pm 
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Cyril R wrote:
E Ireland wrote:
You need a CO scrubber which normally means you have to force the hydrogen through a membrane.

I have seen work that combines the membrane extraction and the forming catalyst in a single frame in an attempt to increase efficiency by forcing CO back into the reformer.

As to cost, it is hard to say at this point but it is safe to say they don't really like vibration.


So if they don't like vibration, how does that match to your claim of them being robust?

What does a 1 kg/h H2 reformer cost?


I never said they were robust?
I was saying that the challenge in engineering a robust one is greater than was first anticipated.


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PostPosted: Jan 10, 2014 1:55 pm 
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E Ireland wrote:
Cyril R wrote:
E Ireland wrote:
You need a CO scrubber which normally means you have to force the hydrogen through a membrane.

I have seen work that combines the membrane extraction and the forming catalyst in a single frame in an attempt to increase efficiency by forcing CO back into the reformer.

As to cost, it is hard to say at this point but it is safe to say they don't really like vibration.


So if they don't like vibration, how does that match to your claim of them being robust?

What does a 1 kg/h H2 reformer cost?


I never said they were robust?
I was saying that the challenge in engineering a robust one is greater than was first anticipated.


Sorry, apologies, I was misreading your last post about it.

What do you think about cost and efficiency if such a unit could be engineered to be robust?

Alternatively, do you consider SOFCs fed directly with low sulphur hydrocarbon (natgas, ultra low S diesel), to be viable for a real world automobile? No reformer needed, but a really hot fuel cell in stead (startup time for heatup would be a bit of an issue for consumer automobiles but let's forget about that for now).


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PostPosted: Jan 11, 2014 12:31 pm 
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I was double checking some compressive loss figures for hydrogen compression. Bossel's result is 12%.

The US DOE

http://www.hydrogen.energy.gov/pdfs/901 ... ession.pdf

Has the following:

Quote:
This record addresses the range of energy requirements to compress and/or cool hydrogen (H2) for storage onboard a hydrogen vehicle. Two physical hydrogen storage methods are considered: H2 gas compressed to high pressure (350, 700 bar) and liquid hydrogen (LH2). Theoretical minimum energy requirements are determined from exergy differences using the standard properties of “normal” hydrogen (25% para-H2 spin isomer) as reported by the National Institute of Standards (NIST) [1]. In all cases it is assumed that H2 gas is initially generated at 20 bar (290 psia). The theoretical energy to compress hydrogen isothermally from 20 bar to 350 bar (5,000 psi or ~35 MPa) is 1.05 kWh/kg H2 and only 1.36 kWh/kg H2 for 700 bar (10,000 psi or ~ 70 MPa). Greater compression energies are required to fill vehicles in practice due to compressor inefficiencies and heating during fast fills. DOE Technology Validation Project data for compression from on-site H2 production is 1.7 to 6.4 kWh/kgH2 [2]. Additional energy required for pre-cooling (as cold as -40 C)[3] to ensure


Taking the average gives 4.2 kWh/kg H2. If that energy comes from a fuel cell running on hydrogen (likely) then at 45% efficiency it requires 9.4 kWh of hydrogen to compress 33.3 kWh of hydrogen to 700 bar. That's guzzling 28% of your hydrogen!

It seems unfair to start at 20 bar for the compressive calculation, that compression has come from somewhere else and must be included. On the other hand, I think this high compressive loss recommends the high pressure electrolyser or high pressure steam methane reforming reactors.

http://en.wikipedia.org/wiki/High-pressure_electrolysis

The Wiki suggests only 3% compressive loss, or (3/0.45 FC efficiency=) 6.7% of the energy content of hydrogen lost.

700 bar steam methane reforming and 700 bar electrolysis, how reasonable/costly is this?


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