Inner cylinder for preheater

The invention discloses an inner cylinder for a preheater. The inner cylinder comprises a cylinder body. A buffer layer is installed on the inner wall of the cylinder body. Arc-shaped ceramic hanging pieces are installed on the inner wall of the buffer layer. Each ceramic hanging piece is composed of a first wedge-shaped hanging plate and a second wedge-shaped hanging plate, wherein the first wedge-shaped hanging plate is in the shape of a big-end-down wedge; the second wedge-shaped hanging plate is in the shape of a big-end-down wedge; the wedge degree of the first wedge-shaped hanging plate is consistent with that of the second wedge-shaped hanging plate; the upper end of the first wedge-shaped hanging plate is provided with a first lug extending towards the bottom end; a first groove matched with the first lug is formed in the position, corresponding to the first lug, of the second wedge-shaped hanging plate; the first lug is matched with the first groove when the first wedge-shaped hanging plate is combined with the second wedge-shaped hanging plate. Second lugs extending upwards are arranged at the top ends of the ceramic hanging pieces. Second grooves which are open downwards and can contain the second lugs in a matched mode are formed in the bottom ends of the ceramic hanging pieces. According to the inner cylinder for the preheater, seamless connection between the ceramic hanging pieces is achieved, and the tightness is high.