Just came across this, and it might give coal a second wind. UCC refers to the process of removing all the compounds from the coal that aren't needed for combustion and cause pollution problems. Doing so will make them easier to deal with than after burning. Even better, they could be put to a useful purpose. It also isn't just the 'bad' compounds (sulfur, mercury, etc.) that removed, but also things that seem benign, like silica, which adds to the mass of the fly ash after combustion. A clean coal powder is the end result that can be more fully combusted in a power plant. It could also replace bunker fuel for shipping. The idea isn't new(the paper is from 2001), but the process is getting closer to being comercially viable. https://www.sciencedaily.com/releases/2006/03/060314085423.htm The production of ultra clean coal by chemical demineralisation - ScienceDirect Ultra Clean Coal (UCC) technology - Yancoal
I don't know about "commercially viable" but coal gassification works but never has been used on a large scale. I can't help but wonder what they will do with the "undesirable" products that are removed. And burning carbon, in whatever form, gives you carbon dioxide. Pretty much no way around that.
Coal gassification was heavily used in Seattle, but shut down in 1956. A lot of 'undesireable' products were dumped into Lake Union or spilled on the ground, and continue to cause some problems: Gas Works Park - Wikipedia But it can be captured and stored underground, such as injected into basalt formations where it is rapidly converted into solid calcium carbonate, similar to chalk. I'm hoping that purer carbon coal will make for easier and cheaper CCS systems, such as burning relatively pure carbon in enriched oxygen (reduced nitrogen) atmospheres in closed systems to reduce the cost of separating the exhaust gases. Of course, this will drive up the cost of coal energy. If it can no longer compete with the falling cost of renewables, then no great loss. But I'd still like to have technically viable ways for burning carbon fuels available in our bag of energy tricks and tools, for times when energy demand is high enough to make it necessary.
Maybe as @fuzzy1 says about about the cleaner exhaust. It should result in more efficient burning in a power plant, so there will be less CO2 per kWh than a traditional coal plant. Some of those undesirable products are only so because they end up in the atmosphere or tied up in the useless fly ash. Take them out and separate them before burning the coal, and they might be desirable and sellable. Sulfur is bad in coal now because it becomes sulfur oxides after combustion and cause acid rain in the atmosphere among other issues. Take it out first, and it's feedstock for the chemical industry. Coal electrical generation isn't going to die out overnight, and we aren't going to stop shipping products around the globe. If we end up burning a fossil fuel, best to do so with as little of an impact as possible.
Do note that I'm not interested in coal without capturing and sequestering the CO2. Any sequestration system will inherently result in fewer kWh per ton of CO2 generated. But the important metrics will be CO2 released to the atmosphere, not counting the portion that gets sequestered. And cost/kWh. Yup, that too.
I am less worried about sequestration, biological means are effective enough. Rather, I prefer seeing higher thermodynamic efficiency along with waste management. Bob Wilson
anything we can do to keep people going hundreds of feet into the earth, working in horrid conditions and dying an early death, i'm all for.
Yea they can, they call it mountain top removal mining, another bad environmental mess. What Is Mountaintop Removal Mining? | Earthjustice
Many shaft coal miners are 'black-lung' sick now. Their employers actively seek ways to not pay health costs. Let coal, going forward, address this. Company off the hook; government on the hook, I don't really care. But nobody paying for help looks bad.
