Flue gas heating device of garbage incinerator

The invention belongs to the field of garbage incineration, and relates to a flue gas heating device of a garbage incinerator. The flue gas heating device comprises an exhaust gas heating pipe, a burner and a hollow pipe, one end of the exhaust gas heating pipe is closed while the other end of the same is open, the open end of the exhaust gas heating pipe is an exhaust gas outlet, a partition is arranged inside the exhaust gas heating pipe, and one horizontal hollow pipe is penetratingly arranged in the middle of the partition to have cavities on two sides of the partition communicated. A flaming pipe of the burner extends from the closed end of the exhaust gas heating pipe into the exhaust gas heating pipe along the axial direction of the same, and the flaming pipe of the burner is concentric with the hollow pipe. An exhaust gas inlet is formed in the side wall, between the inlet end of the hollow pipe and the outlet end of the flaming pipe of the burner, of the exhaust gas heating pipe. One hollow pipe with diameter of the middle smaller than that of two ends is arranged in the exhaust gas heating pipe, flame and flue gas jetted by the burner pass the hollow pipe, certain high-speed negative pressure is formed in the middle necking section, the outlet is expanded rapidly, and accordingly effect of rapid flue gas heating is achieved.