Treatment and recovery method of blast furnace damping-down diffused gas and gas combined treatment system

The invention discloses a blast furnace damping-down diffused gas treatment and recovery method and a gas combined treatment system, and the method comprises the following steps: after blast furnace damping-down, detecting the conveying pressure of a blast furnace gas conveying pipeline; when the conveying pressure is reduced to a first preset pressure, disconnecting the blast furnace gas output pipeline from an external gas pipe network, and communicating the blast furnace gas output pipeline with a converter gas recovery processing pipeline; when the conveying pressure is reduced to a second preset pressure, judging whether the blast furnace damping-down gas meets a recovery condition or not; if the recovery condition is met, the blast furnace gas output pipeline is communicated with the converter gas recovery treatment pipeline; and if the recovery condition is not met, communicating the blast furnace gas output pipeline with a combustion diffusion tower of the converter gas diffusion pipeline. According t