The Briefing Room
General Category => Science, Technology and Knowledge => Topic started by: rangerrebew on February 20, 2017, 07:09:19 pm
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Four-stroke engine cycle produces hydrogen from methane, captures carbon dioxide
Date:
February 16, 2017
Source:
Georgia Institute of Technology
Summary:
When is an internal combustion engine not an internal combustion engine? When it's been transformed into a modular reforming reactor that could make hydrogen available to power fuel cells wherever there's a natural gas supply available.
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FULL STORY
Georgia Tech professor Andrei Fedorov (left) and an undergraduate research assistant Yuzhe Peng are shown with the laboratory-scale hydrogen reforming system that produces the green fuel at relatively low temperature in a process that can be scaled up or down to meet specific needs.
Credit: Candler Hobbs, Georgia Tech
https://www.sciencedaily.com/releases/2017/02/170216130410.htm
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Most hydrogen used today is produced in a high-temperature reforming process in which methane is combined with steam at about 900 degrees Celsius. The industrial-scale process requires as many as three water molecules for every molecule of hydrogen, and the resulting low density gas must be transported to where it will be used.
I wish the article address cost and efficiency, rather than just temperature comparisons.
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I wish the article address cost and efficiency, rather than just temperature comparisons.
Lot's of things are possible in theory that are not practicable due to cost. Wonder which one this will be.
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I wish the article address cost and efficiency, rather than just temperature comparisons.
Considering it's a heat engine that somehow turns methane into hydrogen....
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Considering it's a heat engine that somehow turns methane into hydrogen....
I don't think it is actually an engine performing work. I believe it is the equivalent of an 4 cycle engine being used to provide compression to heat the components.
Unlike conventional engines that run at thousands of revolutions per minute, the reactor operates at only a few cycles per minute -- or more slowly -- depending on the reactor scale and required rate of hydrogen production. And there are no spark plugs because there's no fuel combusted.
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I don't think it is actually an engine performing work. I believe it is the equivalent of an 4 cycle engine being used to provide compression to heat the components.
The energy to turn the engine has to come from somewhere.
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The energy to turn the engine has to come from somewhere.
Yes. Given that it states no fuel is consumed, I assume (due to lack of info in the article) that an outside energy source like a motor is turning the 4 cycle. It talks about varying the rpm to adjust output.
Which is why a discussion of efficiency is important, along with cost.
Lots of things are technically feasible but have no purpose, because they duplicate something already done at lower cost. Often when they don't discuss cost or efficiency in a technical journal, there is a reason.
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Yes. Given that it states no fuel is consumed, I assume (due to lack of info in the article) that an outside energy source like a motor is turning the 4 cycle. It talks about varying the rpm to adjust output.
Which is why a discussion of efficiency is important, along with cost.
Lots of things are technically feasible but have no purpose, because they duplicate something already done at lower cost. Often when they don't discuss cost or efficiency in a technical journal, there is a reason.
Agreed. The overall efficiency is going to be somewhat less than whatever it is for the motive force -- and eventually that probably goes back to a heat engine of some sort. SO ... probably south of 30%.
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Agreed. The overall efficiency is going to be somewhat less than whatever it is for the motive force -- and eventually that probably goes back to a heat engine of some sort. SO ... probably south of 30%.
Steam Reforming Natural Gas to produce Hydrogen runs around 70% efficient including the energy used to create the high heat required.
http://inside.mines.edu/~jjechura/EnergyTech/07_Hydrogen_from_SMR.pdf
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Here's the ACS paper dealing with this device:
http://pubs.acs.org/doi/abs/10.1021/acs.iecr.6b04392 (http://pubs.acs.org/doi/abs/10.1021/acs.iecr.6b04392)
This isn't a free site, unfortunately. If anyone has ACS membership and can look through the paper, let us know if there's any info about efficiency, etc.
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I wish the article address cost and efficiency, rather than just temperature comparisons.
That's because it cannot. Hydrogen bonds are very strong and making pure hydrogen out of anything is a net energy loser and always will be.