A cyclone separator that collects entrained solid particles from a gas stream, comprising a cylindrical body, an inlet duct connected to the body, and a gas outlet tube connected to the body at its upper end. The ratio of the distance between the parallel to a face dropped from the tip of the cyclone separator and the closest point of the gas outlet tube to the internal diameter of the body is at least 0.1, as measured at the lower extremity of the gas outlet tube. The ratio of the inlet duct area, measured at the tip of the cyclone separator and perpendicularly to the face, to the cross-sectional area of the body, is between 0.24 and 0.32. The ratio of the height of the inlet duct to the width of the inlet duct at the tip of the cyclone separator does not exceed 4.