In-furnace heat exchange tube wall temperature monitoring device adopting compressed air cooling protection and method

The invention relates to an in-furnace heat exchange tube wall temperature monitoring device adopting compressed air cooling protection. The in-furnace heat exchange tube wall temperature monitoring device comprises a heat conduction block, a compressed gas tube, a thermocouple and a boiler heat exchange tube. The heat conduction block is arranged on the outer wall surface of the boiler heat exchange tube, the compressed gas tube is fixed above the heat conduction block, and the thermocouple penetrates through the compressed gas tube and is inserted into the heat conduction block. The outer surfaces of the compressed gas tube and the heat conduction block are respectively coated with a zirconium oxide thermal barrier layer. The heat conduction block is made of the same metal material as the boiler heat exchange tube, the width of the heat conduction block is 50%-85% of the diameter of the boiler heat exchange tube, the ratio of the height to the width of the heat conduction block is 1-1.5, and the thickness o