Method for increasing calorific value of low-grade coals

A method for increasing calorific value of low-grade coals, comprising:

• putting materials of coals in an airtight chamber in an inert atmosphere;
• as a first stage, keeping a temperature of the materials of the coals at from 100 to 150 degrees C. so that moisture content is vaporized sufficiently and the vaporized moisture content (vapor) is exhausted from the airtight chamber;
• at the same time, injecting the same amount of inert gas as that of the exhausted vapor in the airtight chamber to always keep the inside of the airtight chamber airtight and in an inert atmosphere;
• moreover, successively heating the coals having been in a fully dried state up to temperatures from 350 to 450 degrees C. to thermally decompose elements contained in the materials,
• individually separating expected elements except for carbon in the atmosphere and in the organic material from bonding with carbon by thermal decomposition in the order from an element having a lower decomposition temperature at a temperature of 450 degrees C. or lower, and exhausting the elements each time of separation to outside of the atmosphere while keeping in an inert atmosphere;
• at the same time, injecting the same amount of inert gas as that of the exhausted separated elements in the airtight chamber to always keep the inside of the airtight chamber airtight and in an inert atmosphere and
• moreover, sealing the obtained upgraded coals in a bulk state in a cartridge while keeping in an inert atmosphere.