We have here an interesting project from Australia. We start with compressing air in order to separate out the nitrogen. This does not have to be a perfect separation and yields of 98% are likely and much less would do.
The oxygen is then blended with exhaust gases to give the same ratios associated air. This will ensure that a more complete burn is achieved as this gas blend is fed into the powdered coal burner. The carbon monoxide could be sharply reduced.
A portion of the exhaust gas is taken off and also compressed in order to liquefy the carbon dioxide.
Of course, this is all doable. The main trick is to get the nitrogen out of system before it gets to the burner itself to hugely reduce the amount of exhaust gases needing compression. Something like this is able to remove most produced carbon dioxide in a transportable form for disposal.
Much is made of geological disposal and my question is it possible to get deep enough to use liquid pressures to keep the co2 liquid in the ground facilitating easy disposal.
This is a coal thermal plant so the heat of compression should be put back into the various heating processes employed by the plant.
I would like to see the reverse Rankin cycle engine integrated with this.
Then we get to the real problem that has made ideas like this fail for decades. It is the problem of compressor efficiency. It has never been good enough to avoid large systemic losses and we are asking here for high volume compressors. It sounds like an engineering nightmare from this distant remove.
I got a solid introduction to the technology thirty years ago and not to be too picky, I see minimal evidence of real improvement. I think that the industry has just never been sexy enough and besides, folks are prepared to make do with designs lifted straight of engine design in particular.
I really would like to find evidence of major improvement, but the only evidence that I note is emphasizes by the organizations on their own reliability. Somehow I suspect that the equipment itself continues to be maintenance demanding.
A lot of energy is currently lost by compressors and we are sticking them on both front and back. Marrying this up with the reverse Rankin cycle could help a bit, but developing a new super efficient compressor for industrial applications was grossly overdue decades ago and is even more compelling today.
Maybe someone has done it?
One other reason I would like something like this to actually work is that grabbing the flue gas gives you an opportunity to collect the heavy metals. That would eliminate the primary source of mercury entering the environment. This is not a minor problem. It is impacting us through our consumption of fish and is endemic in high fish diets although that knowledge is at best suppressed.
I posted last year on the utility of stripping the flue gas stream of SOx and NOx and heavy metal using a chlorine cycle.
The resulting gas was CO2 stripped of its heat and compressor ready.
In the event, these folks are taking a run at using a lot of compression and it will be worth following to see if it has a happy outcome.
Xstrata, J-Power in low-emission coal tech first
SYDNEY (Bloomberg) J-Power and Xstrata PLC have started a 206 million Australian dollar, or $137 million, project in Australia that will be the first in the world to use a low-emission coal-fired generating technology.
The technology may cut typical carbon dioxide emissions from coal-fired generation by about 90 percent.
Schlumberger Ltd., Mitsui & Co. and IHI Corp. are also in the group funding the venture in Queensland state, the Callide Oxyfuel Project said Friday in a statement. The 30-megawatt plant is due to start operating in 2011.
The federal and state governments are contributing A$85 million to the Callide project. The Japanese government and the Australian Coal Association are also providing money for the plant.
"This project will lay the foundation for the widespread deployment of low-emission coal technology so essential for Australian power generation and for the millions of people across the world relying on Australian coal," Australian Resources and Energy Minister Martin Ferguson said Friday in a separate statement.
The venture's oxyfuel technology involves burning coal in a mix of oxygen and recirculated waste gases, instead of air, resulting in higher concentrations of carbon dioxide that can be more easily captured from the exhaust gases.
The carbon waste is then liquefied and buried underground. The technology may cut carbon dioxide emissions from coal-fired generators by about 90 percent, the venture said.
The technology can be fitted at existing coal-fired generators instead of building a new low-emissions plant.