This paper introduces the transformation plan of the fixed grate bed, movable grate bed, air chamber, ash hopper discharge seal and other components of the third and fourth generation grate coolers. The cooling efficiency of the fixed grate bed is effectively improved by adopting the vertical control flow fixed grate bed at the high temperature blanking end, partitioning the fixed grate bed, configuring the quenching grate plate with strong penetrating power, and installing electric butterfly valves in the air supply duct to achieve the rapid cooling of clinker. At the same time, by using longitudinally arranged ventilation grooves, the clinker particles on the movable grate bed can be cooled from multiple directions to form a "cross-flow cooling grate bed", and the thickness and moving speed of the clinker layer can be effectively controlled. After the transformation, when the fan load rate in the heat recovery area is greater than 95%, the secondary air temperature is stable above

1 100℃, the clinker temperature of the grate cooler is less than 65℃ + ambient temperature, the clinker strength is increased by 2~4MPa, and the material fineness is improved.