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A solution to the clean coal conundrum?

As a fuel source, coal has been instrumental in the foundation of the modern world. The great Industrial Revolution, the very gateway to this modern world of ours was powered by coal. Now, coal is an environmental anathema, but for developing countries, coal is is still burning bright. So what’s the solution?

a lump of coalAs a fuel source, coal has been instrumental in the foundation of the modern world. The great Industrial Revolution, the very gateway to this modern world of ours was powered by coal. Now, coal is an environmental anathema, but for developing countries, coal is is still burning bright. So what’s the solution?

Ideas can present themselves in many ways. Ideas can also present themselves in many different places. This particular idea came to me in those strange hours between sleep and wakefulness. The idea came to fruition fully as I stood having just got out of bed.

“Would it be possible to use coal ash to filter and trap the gases from a burning coal fire?”

I had this imperious certainty about the idea being viable, so my first thoughts turned to asking David Bradley, a science writer and scientist with a background in chemistry. If anyone was going to know, David would know.

But let’s go back to the day before, when Kimberly Bock posted an article on Facebook about the new image of coal, which prompted a couple of comments from me:

“There are some very efficient ways of burning coal, and methods of capturing the harmful chemicals released during burning. However, these techniques are expensive and only work on an industrial scale. If someone can miniaturize the size and the cost, then coal becomes viable.

It might be worth looking at the figures for the amount of coal being used in developing countries. These people simply don’t have the means to even consider nuclear power.

Right now, we’re in a transitional period, where old-style fuel sources still need to be supported.”

And that’s the heart of the problem; the developing world really can’t even consider nuclear power as a viable source of energy.

And then the seed on an idea was sown. But I’d need a nights sleep to pull all of the sinuous thought threads together into something more cogent.

In my mind, the ash would need to be combined with a liquid, but not having any knowledge of chemistry, I had no idea what liquid that might be. David pointed me to an article on the lofty subject of: mineral sequestration of CO2 by aqueous carbonation of coal combustion fly-ash.

The liquid would be a weak lime water solution to absorb CO2. So now, if we had a fire chimney with a u-bend, filled with coal ash and lime water, we’d have a chemical scrubber. However, it would require some heat — 30 Celsius. Thankfully, we have a fire!

But what do we do with the waste ash? A local firm had been using fly ash for making breeze blocks out of, a common inner wall insulation building material over here in Britain.

Suitable building materials, especially those that help insulate, are a must in the developing world. So not only do we have a way of removing the CO2 from coal fires, but we also have a means of producing a good building material.

The building blocks of an environmentally friendly coal fire

David confirmed my suspicions, and the idea did at least appear viable. My idea was for some kind of chimney that incorporated a u-bend, into which the coal ash and lime water would be mixed. The gases from the coal fire would permeate the mixture, sequestering the harmful gasses.

Also, the chimney piping itself could be made in such a way as to bring the u-bend close to the fire, warming the lime water to the target temperature.

Once the lime water and the ash are spent, or dry, the resultant mixture can be used to create fly ash “breeze” blocks, which are an excellent and very versatile building material.

This is just a very sketchy, brief imagining of what my idea might look like — even my receding knowledge of engineering tells me that much. So a working model would be required, to know for certain.

Assuming my idea is valid and sound enough to be used, it’d be interesting to explore the potential environmental benefits of having people in developing countries trap and sequester coal fire pollutants on an appreciable scale.

However, the challenges would be manifold; finding a cheap and simple way to build the chimney being the main challenge.

In any case, I’d love to hear from people more familiar with projects in the developing countries, to see if my idea is worth building on, or just nothing more than hot air!

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By Wayne Smallman

Wayne is the man behind the Blah, Blah! Technology website, and the creator of the Under Cloud, a digital research assistant for journalists and academics.

2 replies on “A solution to the clean coal conundrum?”

The idea of clean coal is going to be drawn out just like the concept of global warming. Do I believe that we can develop clean coal technology? Yes. I believe human ingenuity can do anything… but desire isn’t the driving factor here… profit is. After the coal sludge catastrophe in Tennessee recently, how can anyone expect the power companies to do the right thing.

Oil companies, coal companies and even the auto industry work from the model, if it ain’t broke don’t fix it. Improving profitabilty is the only thing they think of. So the question isn’t can we produce energy from coal in a clean fashion, its will we.

Tougher regulation is needed. The only reason that the coal plant in TN has that lake of sludge was because there were no regulations telling them what they need to do with it.

The next problem is time… How long will it take to retrofit those existing plants… can we retrofit them without disrupting the current process?

Throwing money at the problem doesn’t solve it. CEO’s are overpaid to do little work. I read David Bradley’s blog and I think he has some great ideas… but it’s not up to us directly… only indirectly.

The power companies will only do what is required of them when we the people stand up, as our ancestors did and say, “No more.”

Hey, thanks for reading Dan! I wasn’t suggesting this was a solution, it’s Wayne’s idea, I was just chipping in with some thoughts on the chemistry. To be frank, however, coal is the lesser of many evils and seeing as we added scrubbers to remove sulfur (sic) compounds, it probably wouldn’t do any harm to scrub the CO2 as well if it weren’t too great an energy or infrastructure cost. Wind, solar, tidal, whatever, are not ready to displace conventional power stations on the scale required for us all to keep on blogging…

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