2. Tests

2.1 Complex materials and special tests

It's important to remember that solid fuels (and coal in particular) are among the most chemically complex materials present in the earth's crust. Developed over the centuries under diverse geological conditions, their analysis is intended to reveal the slow evolution of the plant precursors of which they are composed.

In other words, it's clear that the characteristics of coal from the Asia-Pacific continent have a completely different profile to that of coal from the European continent, and that this difference can also be seen with coal from the North or South American continents. Within the coal seam itself, there are variations linked to deposits in aquatic and anaerobic basins, their chemical alteration, the depth...