NOVELTY - A system consists of chamber (c1) of coal combusting apparatus configured to pulverize coal feedstock comprising processed biomass/cleaned coal blended compact aggregate, chamber (c2) of coal combusting apparatus configured to pulverize processed biomass pellet feedstock and to feed the pulverized processed biomass pellet feedstock into coal combusting apparatus, and processed biomass system configured to make processed biomass. The processed biomass system comprises beneficiation sub-system, coal cleaning sub-system, blending sub-system and pelletizing sub-system.    USE - System is used for co-firing coal and processed biomass (claimed) for combusting coal used as combustible fuel for generating heat for cooking and heating, and for fertilizing soils for growing agricultural and horticultural product.    ADVANTAGE - The system economically enables co-firing of coal and processed biomass with reduced generation of adverse by-products and minimizing occurrence of explosions.    DETAILED DESCRIPTION - A system consists of chamber (c1) of coal combusting apparatus configured to pulverize coal feedstock comprising processed biomass/cleaned coal blended compact aggregate comprising 10 wt.% or more of coal having sulfur content of 50 wt.% or more which is less than the content of sulfur in coal before passing through coal cleaning sub-system and 10 wt.% or more processed biomass from processed biomass system and to feed pulverized cleaned coal feedstock into coal combusting apparatus in concentration (c1) of feedstock, chamber (c2) of coal combusting apparatus configured to pulverize processed biomass pellet feedstock from processed biomass system and to feed the pulverized processed biomass pellet feedstock into the coal combusting apparatus in concentration (c2) of feedstock with weight ratio of the concentration (c1) to concentration (c2) of 1-9:9-1, and processed biomass system configured to make processed biomass from unprocessed organic carbon-containing feedstock (414) comprising free water, intercellular water, intracellular water, intracellular water-soluble salts, and plant cells comprising cell walls including lignin, hemicellulose, and microfibrils within fibrils. The processed biomass system comprises beneficiation sub-system configured to convert unprocessed organic carbon-containing feedstock into processed organic carbon-containing feedstock having energy density of 17 MMBTU/ton or more, water content of less than 20 wt.%, and content of water-soluble intracellular salt decreased by more than 60 wt.% on dry basis of unprocessed organic carbon-containing feedstock, coal cleaning sub-system configured to convert un-cleaned coal into cleaned coal having sulfur content of 50 wt.% or more, blending sub-system configured to convert cleaned coal and portion of processed biomass into processed biomass/cleaned coal blended compact aggregate with weight ratio of cleaned coal to processed biomass of 1-9:9-1, and pelletizing sub-system configured to convert processed organic carbon-containing feedstock into processed biomass pellets. An INDEPENDENT CLAIM is included for co-firing of coal and processed biomass, which involves passing un-cleaned coal through coal cleaning sub-system to form cleaned coal having sulfur content of 50 wt.% or more, forming processed biomass feedstock pellets by inputting the resultant product into processed biomass system, passing unprocessed organic carbon-containing feedstock through beneficiation sub-system, obtaining processed organic carbon-containing feedstock, passing the resultant product through pelletizing sub-system, obtaining pelletized processed biomass pellet feedstock, passing cleaned coal with portion of processed biomass through blending sub-system, forming processed biomass/cleaned coal blended compact aggregate, providing processed biomass/cleaned coal blended compact aggregate to chamber (c1), pulverizing coal, feeding coal into coal combusting apparatus, providing portion of processed biomass pellet feedstock to chamber (c2) of coal combusting apparatus, pulverizing processed biomass, and feeding processed biomass into coal combusting apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of reaction chamber in beneficiation sub-system.    Reaction chamber (400)    Wet fibril disruption section (410)    Unprocessed organic carbon-containing feedstock (414)    Vapor explosion section (420)    Compaction section (430)