NOVELTY - Preventing operation disrupting mineral residues in pressurized fluidized bed furnace, preferably pressure supercharged stationary fluidized bed furnace (DSWSF), comprises (a) burning fuels, preferably coal other than salty coal, by adding biomass or waste, and (b) supplying calcareous sorbent for flue gas desulfurization and foreign bed materials for stabilizing the fluidized bed in addition to the fuel to the pressurized fluidized bed furnace, where fine-grained calcareous sorbent, and coarse-grained calcareous sorbent are supplied in dry form.    USE - The method is useful for preventing operation disrupting mineral residues in pressurized fluidized bed furnace, preferably pressure supercharged stationary fluidized bed furnace.    ADVANTAGE - The method: avoids operation disrupting residues formation without structural changes in DSWSF-systems and without decreasing desulfurization performance; improves homogeneity of the fluidization in the fluidized bed; increase the separation efficiency of the cyclone unit; achieves uniform, high efficiency and performance of the of the combined cycle process; reduces standstill by malfunction and losses due to reduced performance; is cost-efficient; improves power generation in the DSWSF-systems; reduces stoichiometric ratio of calcium/sulfur due to the better gas-solid contacting in fluidized bed; and reduces the amount of additives to be added to the coal.    DETAILED DESCRIPTION - Preventing operation disrupting mineral residues in pressurized fluidized bed furnace, preferably pressure supercharged stationary fluidized bed furnace (DSWSF), comprises (a) burning fuels, preferably coal other than salty coal, by adding biomass or waste, and (b) supplying calcareous sorbent for flue gas desulfurization and foreign bed materials for stabilizing the fluidized bed in addition to the fuel to the pressurized fluidized bed furnace, where (i) fine-grained calcareous sorbent having particle size of less than 200 mu m, preferably less than 100 mu m, is supplied in dry form in a quantity such that fine-grained calcareous sorbent available for desulfurization of flue gases comprises not greater than 50% stoichiometric lime quantity required for total desulfurization, and (ii) coarse-grained calcareous sorbent having particle size of less than 100 mu m is supplied in dry form in a quantity such that the required total desulfurization is reached with the maximum total desulfurization degree limited by minimum 50 mg/Nm3 sulfur dioxide of dry flue gas, based on 7 vol.% oxygen.