Method and device for quickly cooling blast furnace during shutdown

The invention discloses a method and a device for quickly cooling a blast furnace during shutdown. The method comprises the steps that a channel with the preset length and diameter is opened from an iron notch area to the interior of a hearth, and a nitrogen gun is buried into a coke mixture of the blast furnace hearth through the channel; low-temperature nitrogen equipment is controlled to be started, and low-temperature nitrogen is injected into the coke mixture; state monitoring equipment extends into the blast furnace through the tuyere to obtain the real-time temperature and CO content in the blast furnace; and controlling the pressure of the injected low-temperature nitrogen according to the real-time temperature and the CO content, and when the real-time temperature in the blast furnace is lower than a preset temperature and the CO content in the blast furnace is lower than a preset content, controlling the low-temperature nitrogen equipment to be closed to finish the furnace cooling process. The low-t