| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and apparatus for detecting thickness of coking which is formed by deposition of coke on an inner surface of a heating tube of a process heating furnace, by measuring variation in surface temperature of the heating tube.SOLUTION: Time Tduring which heat passes through a heating tube 1 is obtained using equation T=α/μand is stored into a heat passing time storage part 16, where thermal diffusivity of the heating tube 1 is represented by αand thickness of the heating tube 1 is represented by μ. A thickness calculation part 15 obtains coking thickness μby means of equation μ=[2α×(T-T)], using: processing time Tthat provides a maximum phase difference between a Fourier-transformed phase of temperature change from an inspection target section and a Fourier-transformed phase of temperature change from a healthy section; thermal diffusivity αof coke; and time Tduring which heat passes through the heating tube. |
