Investigation on stress distribution in steam water separator during start-up process can accurately predict the separator's fatigue life

thus to provide references for boiler design

operation maintenance and start-up process optimization.Taking a supercritical 600 MW unit boiler's steam separator as the research object

the temperature and stress distribution during cold start-up process was simulated

by finite element method.Moreover

the working medium pressure was used to calculate the primary stress

then the primary stress was coupled with thermal stress to obtain the peak stress.The results indicate that

the thermal stress is mainly affected by temperature difference between internal and external wall of the separator.With the increasing temperature difference between the inner and outer wall

the thermal stress increases.The primary stress depends on the working medium pressure.It reaches the maximum when the working medium pressure increases to the highest value.The gradient of peak stress on the inner wall near the upper opening area of the introducing tube is great.There is obvious stress concentration in this region.The maximum peak stress located in this region's inner intersecting line between the separator cylinder and inlet pipe.Therefore

this region will become dangerous during the cold state start-up process

which should be paid more attention during the maintenance.