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sCO2 Cycle Starting to Hit the Market

02/23/2015 1:42 PM

http://breakingenergy.com/2014/11/24/supercritical-carbon-dioxide-power-cycles-starting-to-hit-the-market/

This is pretty good stuff. The early issue that I had heard about was the sCO2 dissolving lube oil from the bearings. I suspect they have better bearings now, and have solved the early issues. Your comments? Calculations?

I have made most of my living dealing with water treatment in steam plants, or something related to that. All of that can easily be done away with now, along with all the water treatment associated costs.

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#1

Re: sCO2 cycle starting to hit the market

02/23/2015 2:17 PM

I wonder if we could fit one of those in a vehicle?

http://blog.hemmings.com/index.php/tag/steam/

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#3
In reply to #1

Re: sCO2 cycle starting to hit the market

02/23/2015 3:30 PM

Solar Eagle: Why that is a great question! I bet that sCO2 would be a shoe-in fit for nearly any vehicle, since the thing gets a lot of power in a small package. Could you imagine a 10MW engine in under your hood? I don't think they make a drive train that could take all that, but it might be fun if Myth Busters took it on.

I could for real see this taking place on a much smaller power level, and reducing overall drive train mass. One thing: someone will need to come up with a suitable direct coupled alternator to convert all the torque to e-power, (or hydraulic plus accumulator), since one cannot manage large swings of rpm in these (or steam turbines either).

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#5
In reply to #3

Re: sCO2 cycle starting to hit the market

02/23/2015 3:54 PM

A combination reversible fuel cell could produce the heat for the steam engine which could drive the generator which could supply the electric motors and excess electric could be stored in the fuel cell and battery pack....Wow! what a concept....efficiency near theoretical....ok, probably not really...

http://www.technologyreview.com/news/417053/a-battery-ultracapacitor-hybrid/

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

http://energy.gov/sites/prod/files/2014/03/f11/rev_fc_wkshp_anderson.pdf

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#6
In reply to #5

Re: sCO2 cycle starting to hit the market

02/23/2015 4:02 PM

sCO2 might beat steam in that application due to improved cycle efficiency over steam. Steam still has to make condensate, but I really like cyclone power's radial steam engines, as they do not have to have constant rpm.

I am planning a thermal recovery device using steam right off a fuel cell myself. I cannot find cheap enough fuel cell (and most are in a higher range of power other than the links you provided the other day). I think it has to be SOFC to put out sufficient heat to run a steam engine... do you agree?

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#8
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Re: sCO2 cycle starting to hit the market

02/23/2015 4:56 PM

I actually meant the sCO2 , not steam....but yes SOFC will put out more than enough heat to produce steam, but of course it would have to be scaled to produce proper amount....I'm thinking a regulated heat exchanger using a high temp exchanger fluid....What would a sCO2 exchanger look like?

Reversible fuel cell...

http://fuelcellstore.com/horizon-mini-reversible-fuel-cell

http://www.pnnl.gov/news/release.aspx?id=926

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#2

Re: sCO2 cycle starting to hit the market

02/23/2015 3:26 PM

Better tell Kenny about it. He will jump like a cow. The good oll steam engine no more....:-)��

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#4
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Re: sCO2 cycle starting to hit the market

02/23/2015 3:32 PM

Kenny, Kenny, Kenny. I think I should dedicate this thread to Kenny. Well it might be the end of steam, but definitely not the end of fluid (especially hot dense fluid)...just don't tell Kenny that steam is a fluid.

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#7

Re: sCO2 Cycle Starting to Hit the Market

02/23/2015 4:22 PM

A much more reasonable discussion of the subject is here:

http://www.netl.doe.gov/research/coal/energy-systems/turbines/supercritical-co2-power-cycles

Please note that there are no 760C Rankine power plant cycles operating in the world today. Claims of high efficiency and low water usage based on absurd high operating temperatures should be taken with a grain of salt....

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

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#9
In reply to #7

Re: sCO2 Cycle Starting to Hit the Market

02/23/2015 5:23 PM

Clean coal?

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#12
In reply to #7

Re: sCO2 Cycle Starting to Hit the Market

02/24/2015 10:46 AM

Is there a way for ordinary citizens to view the article in your link to the DoE?

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#13
In reply to #7

Re: sCO2 Cycle Starting to Hit the Market

02/24/2015 11:29 AM

I was aware of an 8 rivers funded build of a 50MWth plant in SE Texas (not sure of exact location, not important right now), but in this one, the fuel will not be PF. It will be natural gas. The air separation plant is pretty much the heart of this beast, as without this, it cannot function at all. Pretty sure the PSA techniques is being utilized here. The only water involved anywhere in this cycle will be the water condensed from the fuel burn downstream of the expander. Pipeline grade CO2 is also a byproduct, approximately equivalent chemically to the carbon content of the fuel. I suspect that early systems as this may stiff suffer from some leakage and thus will experience some CO2 loss from cycle.

I saw where GE is working on seals to combat CO2 losses. One of the additional problems with sCO2 is the issue with oil lubricated bearings. There are other alternatives:

NASA has technology for air-foil bearings consisting of two parts between the journal and the shaft. The bearings are made of high heat resistant materials, and the shaft treated to withstand up to 1200 F. The reasons for this should be apparent and sourced to the cycle temperature, not due to friction. The bearings actually can scrap without galling or over-heating during rotation start, then as speed increases, they produce air flow to "float" the shaft. Link provided explains more, and goes into loading parameters and design issues and improvements.

http://www.nasa.gov/centers/glenn/about/fs14grc.html

Of course, magnetic bearings have made quantum leaps (literally) in the last ten years. These are especially interesting as large loads can be supported easily, and vibration modes can be tuned out, allowing for very smooth operation.

One other technique is porous machined ceramic with air flow through that to support heavy loads. I see no reason why high pressure sCO2 could not be utilized directly with such technology.

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#10

Re: sCO2 Cycle Starting to Hit the Market

02/24/2015 12:43 AM

Next thing we can do is channel DaS Energy.

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#11
In reply to #10

Re: sCO2 Cycle Starting to Hit the Market

02/24/2015 1:57 AM

lol....Burning Man for the brain dead?

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#14
In reply to #11

Re: sCO2 Cycle Starting to Hit the Market

02/24/2015 11:35 AM

I am old and out of touch, I thought DAS Energi was something other than music at first. Maybe will play some of that music to my next electrolysis experiments.

No, I am not attempting to create life. I will let you guess. By the way, others in the small griot I am associated with have achieved some interesting "bump" boiling that throws a considerable portion of the electrolyte and matrix out of the electrolysis vat, and there is a rad count higher than background. Nothing has been rigorously characterized as yet, just some temperature profiling, records of voltage-current, and rad count outside the vat during the "run". If we come up with anything definitive, we will let you all know. Until that time, I won't hold my breath, or waste it attempting to convince anyone, as there is nothing to be convinced of at the moment.

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