Ultra-clean coal – scientific breakthrough?

[IChing]

Contact: Natasha Richardson
[e-mail]
179-344-4404
Engineering and Physical Sciences Research Council

Ultra-clean coal – Could the price now be right to help fight climate change?


A new chemical process for removing unwanted minerals from coal could lead to reductions in carbon dioxide emissions from coal-fired power stations.
There is already a way of burning coal in a cleaner, more efficient fashion that would reduce carbon dioxide emissions: this is where the coal is turned into a gas and used to drive a turbine. However, problems with cleaning the coal before it is burnt have made generating electricity in this way very expensive. This new chemical process could make it more commercially viable.

Under development by a University of Nottingham team with EPSRC funding, the new approach involves using chemicals to dissolve unwanted minerals in the coal and then regenerating the chemicals again for re-use. This avoids the expense of using fresh chemicals each time, as well as the need to dispose of them, which can have an environmental impact. By removing unwanted minerals before the coal enters the power plant the new process helps protect the turbines from corrosive particles.

The aim is to cut unwanted minerals in coal from around 10% to below 0.05%, making the coal 'ultra clean'. Removing these minerals before using the coal to generate power prevents the formation of harmful particles during electricity production. To do this, the team is using specific chemicals to react with the minerals to form soluble products which can be separated from the coal by filtration. This process is known as 'leaching'. Hydrofluoric acid is the main chemical being tested. The chemicals not only dissolve the minerals but are also easy to regenerate from the reaction products, so they are constantly recycled. It is this aspect that has largely been overlooked in past research, but is virtually essential if chemical coal-cleaning is to be environmentally and commercially viable.>>>snip

http://www.eurekalert.org/pub_releases/2006-03/eaps-uc031306.php

[phantom power]

1. At the end of the day...

it's still taking hydrocarbons and releasing the carbon-atoms in the form of CO2. Which will kill us all.

[eppur_se_muova]

2. WOW, this is sloppy reportage...you CAN'T reduce CO2 emissions from COAL!

Coal is mostly CARBON and forms mostly CO2 when it burns. I think most likely this is a means of removing SULFUR dioxide, SO2, and trioxide, SO3, not CO2. SOx is the main culprit behind acid rain (reacts with H2O and air to form H2SO4). It's generated from oxidation of pyrite (FeS2) which is a common contaminant in coal. This would be the "corrosive gases" described farther down in the article.

on edit: As the article notes, ASSUMING we are referring to pyrite removal, this is something that was studied back during the 80's. I did a little of that study myself, which is why I'm sure they are referring to pyrite here. Pyrite is the MAJOR drawback to burning coal "fines" for energy production, as the higher the mineral content of the coal, the more it tends to break up, resulting in the mineral (including pyrite) content of the fines being higher than that of the coal as mined.

[sui generis]

5. I'm skeptical too

anything that justifies continued dependence on a non-renewable resource at the cost of strip mining the U.S. and Canada to table top flatness is worth questioning.

Plus, the straight chemistry of the reaction, as you've pointed out - I doubt this is "sloppy" reporting so much as "coal is our savior and lookie it won't even hurt the environment" propaganda.

[Sal Minella]

3. Any process that takes carbon from underground and puts it in the air

as carbon dioxide cannot be called "CLEAN."

[Brazenly Liberal]

4. Ultra clean coal is like Ultra compassionate conservativism.

http://www.greenpeace.org/seasia/en/asia-energy-revolution/dirty-energy/clean-coal-myth/clean-coal-myths-and-facts">the clean coal myth

[NNadir]

6. This is something I look forward to, leaching coal with hydrofluoric acid.

One wonders what on earth they are imagining here. They apparently have no idea what the use of HF on a multi-million metric ton scale involves.

In any case the most serious pollutant connected with coal is carbon dioxide. The minerals, compared to that, are trivial.

[IChing]

7. I questioned the breakthrough in title of my post. (?)

It may address some of the acid rain problems and dirty air produced by coal, but not CO2.
also it does not address the chemical used itself that makes the "clean coal"

Hydrofluoric acid is by the way has an environmental toxicity score higher than 7 out of 9 ranking systems, in other words, bad.

source:http://www.scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=7664-39-3#hazards

[eppur_se_muova]

8. Maybe not so subtle next time, eh??????????

:) The linked article was not well done--reporter got acid rain, global warming effects confused. Deliberate or not, I don't know--I tend to assume reporters, unless full-time science mag reporters, don't understand the science well enough to get it right.

If coal gasification leads to more efficient burning, yes, that will lead to CO2 reductions since it will take less coal to produce the same amount of energy. But I wouldn't expect the improvement to be huge, and the process still dumps megatons of CO2 into the atmosphere. This process slightly diminishes a large problem, at the cost of sloshing tons of HF about.


"A new chemical process for removing unwanted minerals from coal could lead to reductions in carbon dioxide emissions from coal-fired power stations.

There is already a way of burning coal in a cleaner, more efficient fashion that would reduce carbon dioxide emissions: this is where the coal is turned into a gas and used to drive a turbine. However, problems with cleaning the coal before it is burnt have made generating electricity in this way very expensive. This new chemical process could make it more commercially viable."

edited for clarity

[Odin2005]

9. They can get away with this BS because...

...CO2 isn't considered a pollutant. Fucking rediculous. :argh:

[eppur_se_muova]

10. Thanks for that reminder. ** is re-defining reality into nonexistence. nt