Originally Posted By: dougwalkabout
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.)


Yes smokeless coal is indeed natural coal that has been put through a coking process, though at a lower temperature than true coke. In fact, an old name for it is "semi coke"
Some types are pressed into regular size briquettes, others retain the random shapes of small lumps of coal.

Here in the UK, multifuel stoves are very popular. They are primarily designed to burn logs, but can also burn smokeless coal, but NOT real coal.
The grate of these stoves is adjustable, for wood burning the grate bars are virtually touching so as to give a simulation of a solid surface. When burning smokeless coal, the grate bars have gaps between so as to give a good draft and permit of the ashes falling through to the ash pan.
A separate damper supplies combustion air via the ash pan to the underside of the grate, this should be kept shut when burning logs, but should be partly or even fully open when burning smokeless coal.

I have a small stove of this sort and normally burn logs, but keep a couple of tons of smokeless coal in reserve for emergencies. For a given energy content the smokeless coal takes up less storage space than logs which is a consideration if keeping a large supply.