NOVELTY - A co-firing system comprises 1st chamber for pulverizing coal and feeding into coal combusting apparatus in 1st concentration of feedstock, 2nd chamber of coal combusting apparatus for pulverizing processed biomass pellets from processed biomass system and feeding into coal combusting apparatus in 2nd concentration of feedstock with 1st:2nd concentration ratio of 1:9-9:1, and processed biomass system for making processed biomass from unprocessed organic-carbon-containing feedstock having free water, intercellular water, intracellular water, intracellular water-soluble salts, and plant cells.    USE - A co-firing system for combusting coal in a coal combusting apparatus.    ADVANTAGE - The system reduces adverse by-products during coal combustion. The processed biomass is cleaner than coal and comes from renewable source, e.g. agricultural and plant materials, without burdens of current biomass processes that are inefficient and remove lower, if any, salt content found in unprocessed renewable biomass.    DETAILED DESCRIPTION - A co-firing system comprises 1st chamber for pulverizing coal and feeding into coal combusting apparatus in 1st concentration of feedstock, 2nd chamber of coal combusting apparatus for pulverizing processed biomass pellets from processed biomass system and feeding into coal combusting apparatus in 2nd concentration of feedstock with 1st:2nd concentration ratio of 1:9-9:1, and processed biomass system for making processed biomass from unprocessed organic-carbon-containing feedstock that includes free water, intercellular water, intracellular water, intracellular water-soluble salts, and plant cells comprising cell walls that include lignin, hemicellulose, and microfibrils within fibrils. Processed biomass system comprises beneficiation sub-system for converting unprocessed organic-carbon-containing feedstock into processed organic-carbon-containing feedstock with characteristics that include energy density of greater than or equal to 17 MMBTU/ton, water content of less than or equal to 20 wt.%, and water-soluble intracellular salt content that is decreased by greater than or equal to 60 wt.% on a dry basis from that of unprocessed organic-carbon-containing feedstock, and pelletizing sub-system to convert processed organic-carbon-containing feedstock into processed biomass pellets. An INDEPENDENT CLAIM is included for co-firing coal and processed biomass for combusting coal in a coal combusting apparatus which involves providing coal feedstock to 1st chamber of coal combusting apparatus; making processed biomass pellet feedstock in processed biomass system by inputting unprocessed organic-carbon-containing feedstock into a system comprising 1st and 2nd sub-systems, passing unprocessed organic-carbon-containing feedstock through 1st sub-system, a beneficiation sub-system, via a beneficiation sub-system process, to result in processed organic-carbon-containing feedstock, and passing processed organic-carbon-containing feedstock through 2nd sub-system, a pelletizing sub-system, via a pelletizing sub-system process, to result in processed biomass pellets; and providing processed biomass pellet feedstock to 2nd chamber of coal combusting apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a system for making processed biomass made from unprocessed organic-carbon-containing feedstock and co-fired with coal in a coal combustion apparatus.    Sizing of unprocessed organic-carbon-containing feedstock (2310)    Passing feedstock through beneficiation reaction chamber (2320)    Salt solubilization and washing of feedstock (2330)    Removal of effluent containing microparticles and lignin (2340)    Dewatering and desolvating step (2350)