Apparatus and process for the operation of an environmentally satisfactory coal fired plant

The process for operating a coal-fixed power plant in environmentally sound fashion by reduction of the emission of NO.sub.x and SO.sub.2, said power plant being provided with a boiler structure having at least one firing chamber, said at least one chamber having cooled walls and a burner muffle and an accelerating nozzle, and means for firing said chamber with a coal dust fuel whereby said fuel is heated rapidly before being mixed with combustion air and is rapidly cooled by said walls before being discharged, the steps comprising:

• preparing a coal dust fuel having a surface-active ash, injecting said fuel into the return flow of a flame in said burner muffle, said firing chamber having a load of 5-15.times.10.sup.6 kcal/m.sup.3 hr, heating said coal dust at a rate of at least 1000.degree. C./sec. to a temperature above the ignition point of the coal dust with combustion air at an intensity such that a firing-chamber load of 5-15.times.10.sup.6 kcal/m.sup.3 hr with respect to said burner muffle and said accelerating nozzle is obtained, producing a flame jet in the accelerating nozzle at a velocity of at least 100 m/sec., cooling the flame jet by intermixture with cooled flame gases from the firing chamber in less than 0.1 sec. to less than 1000.degree. C. gas temperature, and discharging the cooled flame gases with at least part of the ash in the form of dust from the firing chamber.