That natural gas power plant with no carbon emissions or air pollution? It works.

[Lord of Planar]

But don't fall for schemes that claim they won't still be introducing CO2 into the atmosphere. The energy comes from the formation of CO2 and it takes more energy than it produces to split them up again. It can't physically work or we would have perpetual energy by making CO2, turning it back into carbon and burning it again.

The system already captures the CO2. Capturing it is the hard part of sequestration. Once captured, it can be pumped deep into the earth where it remains a liquid, and stays put.

 

[JacksinPA]

Where does the carbon go? There will literally be tons of it and it requires a ton of energy to split it away from the O2. Perhaps they have a new catalyst . The cool thing is that they can burn that carbon again and make a perpetual energy generator. :lol: Remember why we burn fossil fuels (or any fuel that burns). It is to combine the carbon atoms it contains with with oxygen which releases energy. Actually it's solar energy that plants stored as carbon compounds.

The CO2 in this summary of the Allam Cycle is pipeline-ready for sequestration, secondary oil recovery or industrial processes.

The Allam Cycle is a new, high-pressure, oxy-fuel, supercritical CO2 cycle that generates low-cost electricity from fossil fuels while producing near-zero air emissions; all CO2 generated by the system is produced as a high-pressure, pipeline-ready by-product for use in enhanced oil recovery, industrial processes, or sequestration.

The base cycle was developed by 8 Rivers Capital and is being commercialized by NET Power, LLC in partnership with Toshiba Corporation, Exelon Corporation, and CB&I. The four parties are currently developing a natural gas-fired power plant to demonstrate this system. Target net efficiencies for the natural gas and coal versions of this cycle, based on current process modeling, are 59% and 52% (LHV) respectively, both with full carbon capture and no other air emissions. Detailed designs indicate that NET Power plants, with full carbon capture, will produce lower-cost electricity than state-of-the-art fossil fuel plants without CCS.

 

[Lord of Planar]

I am a little wary of this as the numbers for the efficency of all of those power plant types don't make sense.

The science of thermodynamics says that the maximum efficency of any heat engine is somewhere near 34%. I could be wrong on that as I never got thermodynamics.

This is not a simple heat engine. It uses the heated CO2 from the burning process as the fluid to run the turbine. It maintains an approximate 95% CO2 in the process, and this makes it hard, for the CO2 not to suffocate the burning process, as only 5% is new fuel and oxygen. I can also see the capture process being rather difficult at scaling up.

They appear to think they can make this work, so let us all cross out fingers and toes.

 

[Lord of Planar]

Detailed designs indicate that NET Power plants, with full carbon capture, will produce lower-cost electricity than state-of-the-art fossil fuel plants without CCS.

I read the opposite, that it will only be lower with current subsidies. It is a more expensive process, and they believe that selling the captured CO2, Argon, and Nitrogen will offset the higher costs as well.

They separate the major gasses from the air first, and end up with ample nitrogen and argon for resale. Part of the near zero or zero emission claim is because they start with pure oxygen separated from the air. No NOx's are produced.

 

[Tim the plumber]

This is not a simple heat engine. It uses the heated CO2 from the burning process as the fluid to run the turbine. It maintains an approximate 95% CO2 in the process, and this makes it hard, for the CO2 not to suffocate the burning process, as only 5% is new fuel and oxygen. I can also see the capture process being rather difficult at scaling up.

They appear to think they can make this work, so let us all cross out fingers and toes.

The heat engine of whatever format has a maximum efficency. I remember it as about 34% but that was due to thermodynamics which I never really got. I have looked at wiki and got a load of very high numbers but I suspect that they are refering to the percentage of output vs the theoretical max.

The turbine rather than the method of heating has this restriction.

The above seems interesting and may well be the future of all heat engines. I don't see a reason not to use something like it in a car.

 

[iguanaman]

The CO2 in this summary of the Allam Cycle is pipeline-ready for sequestration, secondary oil recovery or industrial processes.

The Allam Cycle is a new, high-pressure, oxy-fuel, supercritical CO2 cycle that generates low-cost electricity from fossil fuels while producing near-zero air emissions; all CO2 generated by the system is produced as a high-pressure, pipeline-ready by-product for use in enhanced oil recovery, industrial processes, or sequestration.

The base cycle was developed by 8 Rivers Capital and is being commercialized by NET Power, LLC in partnership with Toshiba Corporation, Exelon Corporation, and CB&I. The four parties are currently developing a natural gas-fired power plant to demonstrate this system. Target net efficiencies for the natural gas and coal versions of this cycle, based on current process modeling, are 59% and 52% (LHV) respectively, both with full carbon capture and no other air emissions. Detailed designs indicate that NET Power plants, with full carbon capture, will produce lower-cost electricity than state-of-the-art fossil fuel plants without CCS.

So there is no reduction in CO2 production at all but it "captures" the gas for other uses or sequestration. At least that makes logical sense. The next question is what do do with it that keeps it out of the air.

 

[faithful_servant]

I agree. I haven't read the full article & the details of the novel process they are using but it states that the carbon dioxide formed from burning natural gas is consumed in a later step in the combustion cycle.

So where exactly does the carbon end up?? It doesn't just disappear, so where is it?

 

[Lord Tammerlain]

So where exactly does the carbon end up?? It doesn't just disappear, so where is it?

Sent for sequestration

In Alberta it means being pumped into old oil and gas wells

 

[Lord of Planar]

The heat engine of whatever format has a maximum efficency. I remember it as about 34% but that was due to thermodynamics which I never really got. I have looked at wiki and got a load of very high numbers but I suspect that they are refering to the percentage of output vs the theoretical max.

The turbine rather than the method of heating has this restriction.

The above seems interesting and may well be the future of all heat engines. I don't see a reason not to use something like it in a car.

I don't like wiki as a source, but this is quick, and they are generally correct on non-partisan issues:

The efficiency of various heat engines proposed or used today has a large range:

3%[4] (97 percent waste heat using low quality heat) for the OTEC ocean power proposal.
25% for most automotive gasoline engines [5]
49% for a supercritical coal-fired power station such as the Avedøre Power Station, and many others
60% for a steam-cooled combined cycle gas turbine.[6]
​

https://en.wikipedia.org/wiki/Heat_engine

This new design is a "supercritical" design.

Answer: Maximum efficiency

= (THOT – TCOLD)/THOT

= [(510+273) – (30+273)] / (510+273)

= 480 / 783

= 0.61 or 61%
​

Episode 606: Heat engines and thermal efficiency

 

[faithful_servant]

Sent for sequestration

In Alberta it means being pumped into old oil and gas wells

So what we have is simply a new way of sequestering CO2 that creates a less efficient power source?? Is that what I'm hearing?

 

[Threegoofs]

So what we have is simply a new way of sequestering CO2 that creates a less efficient power source?? Is that what I'm hearing?

Sounds like it.

But that probably wasnt sexy enough to clarify in the article.

The issue of what to do with sequestered CO2 still remains.

 

[Lord Tammerlain]

So what we have is simply a new way of sequestering CO2 that creates a less efficient power source?? Is that what I'm hearing?

Most likely


A more effective method would be to promote planting of fast growing plants (bambo) which are cut regularly and then just buried or put on shorelines to reduce soil erosion

 

[Lord of Planar]

So what we have is simply a new way of sequestering CO2 that creates a less efficient power source?? Is that what I'm hearing?

It's actually a very efficient energy source. Just complicated to implement, and possibly not viable to do so.

 

[faithful_servant]

It's actually a very efficient energy source. Just complicated to implement, and possibly not viable to do so.

You're right, I missed that part of the article. It's actually a application of something that I've always been interested in - capturing all that waste heat from every power generating plant that uses steam and putting it to work doing SOMETHING. I always thought that a co-generation facility that coupled a power plant with a smelter would be great way to put that waste heat to work. Instead of pumping the heat into the atmosphere, find a way to use it preheat the metal prior to it going to the smelter, saving the cost of those few degrees of heat the smelter has to generate. I always wondered if the "$/degree" would be worth it.

 

[Tim the plumber]

I don't like wiki as a source, but this is quick, and they are generally correct on non-partisan issues:

The efficiency of various heat engines proposed or used today has a large range:

3%[4] (97 percent waste heat using low quality heat) for the OTEC ocean power proposal.
25% for most automotive gasoline engines [5]
49% for a supercritical coal-fired power station such as the Avedøre Power Station, and many others
60% for a steam-cooled combined cycle gas turbine.[6]
​

https://en.wikipedia.org/wiki/Heat_engine

This new design is a "supercritical" design.

Answer: Maximum efficiency

= (THOT – TCOLD)/THOT

= [(510+273) – (30+273)] / (510+273)

= 480 / 783

= 0.61 or 61%
​

Episode 606: Heat engines and thermal efficiency

I read that and it disagrees with my 30 year old memory of mechanical engineering that I droped out of due to, amongst other things, not being able to understand the whole thermodynamics and entropy thing. So.....?

 

[Tim the plumber]

So what we have is simply a new way of sequestering CO2 that creates a less efficient power source?? Is that what I'm hearing?

More efficent if you subsidise it and don't include those subsidies in the balance sheet.

 

[late]

The open question is could atmospheric carbon dioxide be captured & burned in a modified combustion cycle. I

No, the numbers are too big.

 

[Tim the plumber]

You're right, I missed that part of the article. It's actually a application of something that I've always been interested in - capturing all that waste heat from every power generating plant that uses steam and putting it to work doing SOMETHING. I always thought that a co-generation facility that coupled a power plant with a smelter would be great way to put that waste heat to work. Instead of pumping the heat into the atmosphere, find a way to use it preheat the metal prior to it going to the smelter, saving the cost of those few degrees of heat the smelter has to generate. I always wondered if the "$/degree" would be worth it.

See above about my not understanding etc... but here goes;

The way the universe works is that the qulaity of the heat is important. A large amount of energy in the form of a bath of look warm water is not useful but you can use the small amount of heat in an electric bulb to light a room.

The waste heat coming out of a power plant is the stuff they could not use effectively. As I remember it, I nevver really got it though, it was about a third of the heat energy was converted to electrcal power, a third went up the cooling towers and a third lost to entropy. The entropy part blew my mind. As did the tonsilitis I had so I dropped out.

The warm water in the cooling towers has had all the useful heat taken ot of it by the power station. It is still hot enough to use for greenhouses, swimming pools, distrcit heating and fish farms. But not really useful for power generation.

 

[faithful_servant]

See above about my not understanding etc... but here goes;

The way the universe works is that the qulaity of the heat is important. A large amount of energy in the form of a bath of look warm water is not useful but you can use the small amount of heat in an electric bulb to light a room.

The waste heat coming out of a power plant is the stuff they could not use effectively. As I remember it, I nevver really got it though, it was about a third of the heat energy was converted to electrcal power, a third went up the cooling towers and a third lost to entropy. The entropy part blew my mind. As did the tonsilitis I had so I dropped out.

The warm water in the cooling towers has had all the useful heat taken ot of it by the power station. It is still hot enough to use for greenhouses, swimming pools, distrcit heating and fish farms. But not really useful for power generation.

That's why I always thought that finding ways to use co-generation to put that heat to work could be such a huge deal. If all those calories went into pre-heating metals prior to smelting, that's that much less energy it would take to smelt the metal. Maybe it's only 1% of the total, but that 1% would be a substantial savings in cost and energy.

 

[Tim the plumber]

That's why I always thought that finding ways to use co-generation to put that heat to work could be such a huge deal. If all those calories went into pre-heating metals prior to smelting, that's that much less energy it would take to smelt the metal. Maybe it's only 1% of the total, but that 1% would be a substantial savings in cost and energy.

That's the thing about quality of energy;

All the messing around with loads of pipework to get the warm water to the ore would be much too much hassle for it to be worth wile for the slight warming of the material. The pipes rust and get damaged etc..

 

[JacksinPA]

Sounds like it.

But that probably wasnt sexy enough to clarify in the article.

The issue of what to do with sequestered CO2 still remains.

Secondary oil recover is one major use for the CO2 which is also used industrially.