Flue gas waste heat recovery device of gas-fired boiler

The utility model relates to the technical field of gas-fired boilers, in particular to a flue gas waste heat recovery device of a gas-fired boiler. According to the technical scheme, the boiler comprises a shell, a boiler body and a fixing pipe, a gas inlet pipe is fixedly embedded into the boiler body, the end, away from the boiler body, of the gas inlet pipe is fixedly embedded into the shell, a gas outlet pipe is fixedly embedded into the end, away from the gas inlet pipe, of the shell, the gas outlet pipe is in gas communication with the shell, and a fan is installed in the gas outlet pipe; a coil pipe is arranged on the inner wall of the shell, a filter screen is welded to the inner wall of the shell, a filter element is installed on the inner wall of the shell in an attached mode, fixing pipes are welded to the two ends of the inner wall of the shell, water storage tanks are welded to the top end face and the bottom end face of the shell, water pumps are installed in the water storage tanks, and the wa