Substantiation of causes for damage of water-wall tubes of an external salt compartment of a high-pressure boiler

2014 ◽  
Vol 61 (10) ◽  
pp. 724-730 ◽  
Author(s):  
A. I. Fedorov
2014 ◽  
Vol 912-914 ◽  
pp. 456-459
Author(s):  
Na Xu ◽  
Jun Bo Shi ◽  
Yong De Li ◽  
Wei Min Guo ◽  
Xiao Feng Wu ◽  
...  

In this case study, the corrosion failure analysis of high-pressure boiler water-wall tubes in a power plant was investigated by means of the chemical analysis, metallographic examination and scanning electron microscope (SEM) observation. Energy dispersive spectroscopy (EDS) was used to examine the changes of test materials and corrosion products. Based on the failure process of the boiler water-wall tubes and the experimental results, a conclusion was drawn that the failure of water-wall tubes was mainly caused by pitting corrosion. Sulfide and chloride attack was the major cause of localized pitting corrosion on the inner surface, and the outer surface damage was mainly due to the synergism of high temperature sulfide corrosion and flue gas erosion.


Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.


Sign in / Sign up

Export Citation Format

Share Document