Progress of Cryogenics and Isotopes Separation , ISSN: 1582-2575
2002, Volume 5, Issue 9+10

Cercetari asupra determinarii rezervei duratei de viata a conductelor de abur viu din termocentrale

Abstract

The safe exploitation of the active vapour ducts prescribes periodic inspections of the structural status and of the properties of the utilized materials.
There are possibilities to establish the structural evolution and that of the materials’ properties through destructive or non – destructive methods.
Currently, we mostly employ destructive methods through which we establish the microstructure of the material and the mechanic features at the exploitation temperature at certain periods of time.
Lately we employ non-destructive methods of approaching the structural evolution with temperature and work duration.
The work presents the establishment of the reserve of the life span of a duct with a 426 mm diameter and 16 mm thickness, which work for 84.556 hours at a temperature of 540^oC and a pressure of 2.44 MPa within a thermo – electric power station.
By creep trials we established that this duct could also be exploited for 16.000 … 28.000 hours.
Using the Struers retorts and establishing the “A” parameter of the degradation in time of the microstructure, we established a maximum duration of safe exploitation of this duct, of 16.065 hours.
Although the non – destructive method is les laborious and doesn’t necessitate the sampling from the ducts, it should be adjusted with moderation until there is perfected the methodology of the establishment of the degradation of the grains limits. We recommend that the non – destructive method be presented in order to be employed currently with informative character.