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On 6/3/2019 at 12:56 AM, Marina Schwarz said:

Same reason CO2 makes a superior fluid for a power turbine as well.  Lower friction.  Much larger critical fluid region at a higher T & P so you do not get cavitation which means more efficient to pump attaining a high pressure.

A CO2 turbine instead of steam for same power output can be ~4X smaller or more depending on T&P of course

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As for the win-win.... no.  From a CO2 fanatic you would leave... some CO2 in the ground... As if.... it will ALL come back out with the gas and oil and you still have to make the CO2 to begin with which requires a lot of energy instead of essentially free water(its not, but in comparison)

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I see. Thanks for that, it's very informative. It seems a waste-free option is hard to come by but still better to put some of it good use, right? Unless doing it is very energy-intensive and offsets the benefits?

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(edited)

17 minutes ago, Marina Schwarz said:

I see. Thanks for that, it's very informative. It seems a waste-free option is hard to come by but still better to put some of it good use, right? Unless doing it is very energy-intensive and offsets the benefits?

If you could get this CO2 straight from a pipe and direct inject it into the  ground from say a NG powerplant... ok.  In fact several plants over coal, oil are doing EXACTLY this already, but more to just increase pressure.  Given enough time could create methane.  But how often will this happen?  Not often.  Or you truck it and you need a Million gallons of liquid CO2 per well.  Yea, that is not going to happen.  All those insulated trucks need hazmat cert drivers now because if they crash and a rupture occurs; must clear the area.  Holy expensive gonads!   Which means only practical solution would be piping it around in compressed gas form and then further compressing it at the well head.  Yea, as if there are extra pipes .... not just any piping, but HEAVY walled HIGH pressure pipes just laying around waiting to be filled with the equivalent of CNG...  Right!f

On a diff note: Naval design has wanted more compact gas steam turbines for a LONG time, the problem is battle damage.  Battle blows a hole and all that CO2 comes out.... Assuming everyone is not asphyxiated...You then need equipment to make said CO2 out of the air as said turbine has to operate just above its critical point(EDIT << Idiot me said above, meant below>>. .  Who says the equipment to make said CO2 is not damaged?  If this is a normal ship and a hole gets blown into the power turbine, you just refill with water from the desalinator on every ship already.  In a pinch you could operate on salt water.... 

On a good note: If a hole is blown in said CO2 turbine, at least you do not have to worry about fires.... 😜

Edited by Wastral
Edit for stupidity...
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Now, if CO2 is available from say flaring.... 🙄 and one can somehow use that to just mix with the water/sand cocktail for FRACKING who knows.  Not sure it would do anything as it would just dissolve into the water and I doubt it would lower surface tension any.  Funny things happen at high pressures, so, I do not know regarding the mix ratio, and then you only get partial benefit. 

As the saying goes, one man's trash is another man's treasure so...

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6 hours ago, Wastral said:

If you could get this CO2 straight from a pipe and direct inject it into the  ground from say a NG powerplant... ok.  In fact several plants over coal, oil are doing EXACTLY this already, but more to just increase pressure.  Given enough time could create methane.  But how often will this happen?  Not often.  Or you truck it and you need a Million gallons of liquid CO2 per well.  Yea, that is not going to happen.  All those insulated trucks need hazmat cert drivers now because if they crash and a rupture occurs; must clear the area.  Holy expensive gonads!   Which means only practical solution would be piping it around in compressed gas form and then further compressing it at the well head.  Yea, as if there are extra pipes .... not just any piping, but HEAVY walled HIGH pressure pipes just laying around waiting to be filled with the equivalent of CNG...  Right!f

On a diff note: Naval design has wanted more compact gas steam turbines for a LONG time...

My understanding was that most military ships run on Brayton cycle turbines, which don't use steam and are far more compact.  Naval nuclear reactors run steam, but they're rare exceptions.  A leak in a naval nuke would also be at least as deadly as CO2, so battle damage isn't as much of a risk there. 

Commercial ships probably still use steam, but then battle damage isn't a concern.  Could CO2 be made sufficiently safe for commercial shipping?

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(edited)

19 minutes ago, BenFranklin'sSpectacles said:

My understanding was that most military ships run on Brayton cycle turbines, which don't use steam and are far more compact.  Naval nuclear reactors run steam, but they're rare exceptions.  A leak in a naval nuke would also be at least as deadly as CO2, so battle damage isn't as much of a risk there. 

Commercial ships probably still use steam, but then battle damage isn't a concern.  Could CO2 be made sufficiently safe for commercial shipping?

Nope: talking nucs and Brayton.  True, most are subs, but the carriers would love to downsize their steam turbines.

Thing is due to compact nature of CO2 over steam due to its much higher T& much lower P allowables, Kerosene fired closed system CO2 turbine would be more efficient. A not inconsequential problem for the modern destroyer which does not have much range operating at 30+ knots. The whole reason the old oil fired steam turbines were retired is that for efficiency MUST need higher T obviously and with working fluid of water, you cannot get this without MASSIVE pressure as well. 

Pretty sure nearly 100% of every civilian ship uses the Diesel cycle with reheat.  I do believe the last steam power plants disappeared in the 90's.  I could be wrong here.  Naval design is not my wheel house to say the least! 

As for civilian use, the efficiency quoted in the article I read were still below Diesel + turbo superchargers and reheat, but getting close.  Those modern ships are VERY efficient.  Civilian shipping does not generally have a specific power constraint like the Navy.  Or should I say a desire for a higher specific power allowing one to carry more missiles etc.  Frankly I think using Brayton cycle turbines on destroyers breaks the KISS principle for damage tolerance etc, but since no one else effectively has a navy... the USA and its NATO allies have been able to get away with this much more expensive option for theoretically more efficient warships. 

Edited by Wastral
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1 hour ago, ceo_energemsier said:

Excellent pull.  Keep reading about super critical CO2 cycles for last 2 decades... hrmm more like 3 actually and looks like we might finally see one.  Very very very interesting and they are doing CO2 capture as well.  Hrmmm, talk about MASSIVE opportunities if this works as advertised! 

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3 minutes ago, Wastral said:

Excellent pull.  Keep reading about super critical CO2 cycles for last 2 decades... hrmm more like 3 actually and looks like we might finally see one.  Very very very interesting and they are doing CO2 capture as well.  Hrmmm, talk about MASSIVE opportunities if this works as advertised! 

We have used CO2 for EOR and also piping CO2 from stationary sources (very close proximity) to oil and gas wells for EOR.

I have seen a lot of wells fractured with CO2 and they seem to have done very well and the production is still stable from them after 14 months if not more.

I think the Japanese will end up fast tracking the ciritical CO2

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3 minutes ago, ceo_energemsier said:

We have used CO2 for EOR and also piping CO2 from stationary sources (very close proximity) to oil and gas wells for EOR.

I have seen a lot of wells fractured with CO2 and they seem to have done very well and the production is still stable from them after 14 months if not more.

I think the Japanese will end up fast tracking the ciritical CO2

Yes, EOR been done for a long time, but this is a game changer if works as advertised.  This means the producers/users of CO2 now need to be co-located where the FRACKING is taking place.  It means where a LOT of companies do business will be changing location.  Transporting CCO2... is a nightmare.  No, it is not as restrictive as LOX, but... massively expensive.  This is not going to be happening via long distance trucking.  Just things to think about going forward. 

Thanks for the link, will be watching these guys VERY closely. 

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13 minutes ago, Wastral said:

Yes, EOR been done for a long time, but this is a game changer if works as advertised.  This means the producers/users of CO2 now need to be co-located where the FRACKING is taking place.  It means where a LOT of companies do business will be changing location.  Transporting CCO2... is a nightmare.  No, it is not as restrictive as LOX, but... massively expensive.  This is not going to be happening via long distance trucking.  Just things to think about going forward. 

Thanks for the link, will be watching these guys VERY closely. 

It will be very feasible in ND, TX, NM , WV, PA where many gas processing and other such facilities have been built and are being built and many more to be built, including coal and gas fired power plants.

Refineries  are planned to be built within the Permian basin.

We have a design to utilize SCO2 for power use in a  couple of proposed refineries

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