Interesting, I hadn't heard of smokeless coal. It looks like coal that has been put through a coking process and then pressed into briquettes with a binder added to the mix.

(It occurs to me that the el cheapo barbecue briquettes I tried once were made from coal -- that would explain the price, and the flavour. Never again.)

To reiterate, though: a modern airtight wood burning stove will not burn coal well, and doing so will void the warranty. A grate and an additional layer of protection below would have to be added to take the intense localized heat. The door would probably have to be cracked open the entire time. I have no idea what the effect on a catalytic wood burner would be. (The good news is that antique coal/wood stoves can be had for a song, even free; but no building code or insurance company would allow them in a residence.)