Device and method for determining gas permeability of cohesive zone coke layer

The invention discloses a device and a method for determining permeability of a cohesive zone coke layer. The device comprises an iron ore high-temperature melting drop performance tester and a material accommodating crucible, wherein an airflow tube array is inserted into the material accommodating crucible and comprises a plurality of airflow branch tubes which are open in the lower parts and arranged from bottom to top in a gradient manner; each airflow branch tube is communicated with a corresponding gas branch tube, and a flowmeter is arranged on each gas branch tube; and the gas branch tubes are converged to a main gas pipeline which is communicated with a high-pressure nitrogen tank or a high-pressure nitrogen pipeline provided with a stop valve. The device and the method can detect softening, melting and drop performance of the iron ore and can detect the permeability condition of the coke layer simultaneously, the permeability condition after the melting erosion of the coke layer by the iron ore melting and the permeation rate of the iron ore in the coke layer can be reflected conveniently and quantitatively according to a test result, meanwhile, blast furnace production can be guided timely, and data support is provided for distribution adjustment and burden structure optimization of the blast furnace.