Moisture content in solid fuel

Downthedrain

My last delivery of solid fuel yesterday morning (Blackjack smokeless ovoids) looked to be a short measure. 4 bags usually fills my bunker exactly, but this time it was considerably less and the fuel was soaking wet.

I wondered how much the water affected the delivered weight:

Hetas says "It is not uncommon for your coal-based fuels to be delivered wet, and this is not a cause for concern. Many merchants store their coal-based fuels in large piles open to the elements, meaning that when they load up your delivery, your fuel may remain wet……..When soaking wet, MSFs are likely to only have a moisture content of up to 15%, the majority of which is surface water which can be quickly dried off."

I decided to check this for myself and used my digital postage scales to check several individual samples. Each one was dried of superficial moisture with kitchen towel and any adhering particles removed. Only undamaged, whole whole ovoids were chosen. 5 individual pieces ranged in weight from 83g to 88g and were dried overnight by placing them on the top of our solid fuel stove. The weight was checked this morning, which ranged from 72g to 73g.

The total moisture content by weight averages out to 16.13%, which represents a significant thermal and financial penalty when the fuel costs £29.50 for 50Kg. A proportion of the energy is also lost in driving off the moisture and this adds to pollution and chimney damage.

We also have oil heating and before winter I worked out that solid fuel was marginally cheaper for us, but the balance shifts towards oil once the calorific value of the solid fuel is reduced accordingly.