Abstract:

In order to prevent superheater tube burst caused by oxide coat peeling in a power generation company, pipe cutting inspection was carried out during unit overhaul.In the recovery process with argon arc welding, a special type of “instant watersoluble paper” was used to seal both ends of the weld in order to make the weld be protected by argon atmosphere.The hydrogen conductivity of the main steam of the unit repeatedly exceeded the standard after being connected to the grid.The main reason is that the superheater had not been washed sufficiently before the unit startup.The content of chloride and sulfate in the instant watersoluble paper is too high.The residual watersoluble paper continuously releases impurity ions such as chloride and sulfate after the unit startup.It is the main reason for the abnormal high hydrogen conductivity of main steam.Preventive measures are put forward to ensure that the quality of main steam reaches the standard.

Key words:

font-size: 10.5pt, mso-spacerun: 'yes', mso-font-kerning: 1.0000pt">water soluble paper;argonfont-size: 10.5pt, mso-spacerun: 'yes', mso-font-kerning: 1.0000pt">font-size: 10.5pt, mso-spacerun: 'yes', mso-font-kerning: 1.0000pt">arc welding;main steam;hydrogen conductivity;limiting molar conductivity;carboxymethyl cellulose