Coal: the cleanest energy source there is?

Yeah, but find that in the Fox article? Instead: "The only waste product is therefore water and coal ash -- no greenhouse gases" Most of the energy penalty of CCS is in the S, which this still requires. It might be a modestly better engineering solution than other approaches to CCS. It might not. S is still the problem. Which Fox seems conveniently to have ... assumed away? failed to mention? Genuinely thought the carbon vanished? Tough to say. Based on the OP and thread, the article succeeded in being substantially misleading.

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Or, in other words, CO2 is still the problem.

Whatareyagonnado with it all? There may be a market for the small amount generated by a pilot plant but the amount generated by a full size coal plant is way more than anyone wants -- especially if lots of other coal plants are doing the same thing.

 

Is there any hope of turning it into solid carbonate minerals, either up here or after being injected deep underground? I don't have enough chemistry to know if there are any practical choices that leave usable net energy.

 

In a fluidized bed combustion coal plant the equipment to sequester would add about 5 cents per kwh. The high costs are in the separation for capture right now. In an IGCC most of the pollutants are removed before combustion so sequestration is less expensive. DOE is helping to fund such a plant in the oil patch of Texas. The plant will sell the carbon dioxide to use in petroleum recovery. At least as importantly it is being build to take the sulfur and nitrogen and sell it as sulfuric acid and fertilizer. This equipment is expensive though, and it cost more to recover these products than simply leave them as pollution.

I think it is proper to think of carbon dioxide as a product instead of a pollutant if you are capturing and using it. Agree the news article failed to spell that out, and left a bad impression. If the power plant is by oil fields using the CO2 is much more cost effective, if it is far away then that will add additional costs. If a large number of power plants do the capture though the amount captured will be greater than the need, and it will become waste. In the case of the texas IGCC ccs plant there is a plan to sequester this in the geological formations near by, but most of the country does not have these formations.

The idea is to pump it into geological formations if you can't sell it for a usefull purpose. The Norwegians have been doing this for decades, but you need a suitable geological formation. Yes you can turn it into other materials, one such use is to use it to inject to algea pools where they use it to help generate biofuels. You can turn it into other things too, but pumping it into a proper geological formation is the least expense right now.

 

Since it's not combustion, it might be easier to control and allow for greater efficiency when not 24/7 baseload. Less of an issue here, but valuable in other countries.

Of course, being coal the devil could be in the need to be massively scalable.

I wonder if it will increase the scrap value of rusty iron.

 

Using it for algae for biofuel still puts in the atmospheric carbon cycle, so that is still not desirable. I'd like to put it into the ground in some form that we know won't vent back out after after the well caps rust and crumble.

 

I don't know either but apparently nobody has come up a practical way of doing that yet that is broadly applicable in the different locations and conditions where coal generation plants exist.

 

Sulfur if recovered as H2S is converted to elemental sulfur (no prob).
If recovered as SO2 you could convert to gypsum (wall board) but normally this not possible in coal due to other impurties. CO2 can be injected into earth, I am thinking.

 

These are special reusable iron pellets. They oxidize - rust - quickly when pulled out of the chamber and allowed to be in air, then can be reused. Any scrap iron can be recycled into these things though.

The key thing is not controlling the heat of combustion, that is actually a draw back here versus just burning the coal. It allows for easy clean up. Most of the bad stuff stays in the ash, instead of going up the smoke stack oxidized. That means you don't need to pay for scrubbers to remove particulates, SO2, and NOx. The CO2 is left in a concentrated form in the chamber for easy separation, instead of being mixed with lots of other stuff. The pellets should be able to be easily removed from the bed, but I"m guessing that temperatures of reaction have to be kept in a narrow range to not create those other nasty gasses. The key is you are trying to get one reaction C + iron oxide -> CO2 + iron, and avoid things like S + O2 -> SO2.

DOE and Ohio State are talking a decade to commercialization. THat makes me think that it won't be cost effective unless the caps on SO2 and NOx are stricter than they are now or if there is a price charged for releasing CO2.

Absolutely true, but currently people are paying for carbon dioxide for algea and petroleum recovery. So recycle is best at small quantities. Reduce by using wind, geothermal, and solar for part of the load.

When quantities get high, then sequester. Say that we can get coal down to 25% of power (It was 36% for the first 9 months of 2012, and 45% in 2009), Maybe 10% of the co2 could be recycled for algea and petroleum recovery, and hopefully a good portion of the other 90% might be able to be sequestered. If only1% is captured all of it can be recycled, but the problem is not enough is being captured.

 

http://www.netl.doe.gov/publications/proceedings/09/CO2/pdfs/5289 Ohio State chemical looping (Li) mar09.pdf

 

What would keep the injected CO2 from migrating back to the surface? Just thinking out load.

DBCassidy

 

AG has a point, that if the cost is right then this chemical oxidation can stand on it's merit of removing non greenhouse gases from the air when coal is used.

So far as greenhouse gases go, I wonder if advances in engineering will improve the heat extraction efficiency compared to current best tech combustion. After all, some 60+ percent of combustion heat is now automatically going up into the sky.

The best case I can imagine is for coal to become as 'clean' and efficient as natural gas. An added bonus would be if the chem-ox coal plant could be run efficiently as needed, at low loads. Because while I have no doubt that the large majority of energy production can and should be clean from PV and wind, at least in the near term fossil fuels are going to cover demand spikes and clean production lapses.

 

something to consider with this approach is that since there are near-zero emissions, the plant can be located within population and manufacturing centers and the low heat energy directly used. while distribution of the low heat energy is typically with hot water, this process could also distribute the heat as hot CO2 on it's way to a sequestration site and algae farm.

 

Bravo Sage, that was a relatively positive and upbeat post and energy related. Nice.

 

That I can do without