Caustic Corrosion Failure of Back Wall Riser Tube in a High-Pressure Boiler

2011 ◽  
Vol 11 (4) ◽  
pp. 357-362
Author(s):  
M. Mobin ◽  
A. U. Malik
Keyword(s):  
High Pressure ◽  
Back Wall ◽  
Corrosion Failure

scholarly journals Crystallization Behavior of Ammonium Chloride in High-Pressure Heat Exchanger of Hydrotreating Unit

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jianwen Zhang ◽  
Fan Zhang ◽  
Yan Li ◽  
Yahui Zhao ◽  
Gang Sheng
Keyword(s):  
Mass Transfer ◽  
High Pressure ◽  
Heat Exchanger ◽  
Ammonium Chloride ◽  
Volume Fraction ◽  
Flow Direction ◽  
Corrosion Cracking ◽  
Inlet Temperature ◽  
Corrosion Failure ◽  
Chloride Deposition

In view of the corrosion failure of a high-pressure heat exchanger in a diesel hydrogenation unit, the formation mechanism of ammonium chloride in a multiphase flow system is investigated in this article. Numerical simulation is carried out by user defined function (UDF) on the process of adding source of mass transfer in computational fluid dynamics (CFD) solvers. The distribution characteristics of ammonium chloride are illustrated by the parameters including crystallization temperature of ammonium chloride, volume fraction of ammonium chloride, and mass transfer rates of NH3 and HCl, and the causes of corrosion cracking in the U-shaped bend of the heat exchanger are discussed. The results show that there is a great risk of ammonium chloride deposition in the heat exchanger from 4.5 m away from the outlet of the second pass. The crystallization area in the tube gradually expands from the wall to the center along the flow direction, and the crystallization rate is higher near the tube wall. The field sampling test results show that the corrosion cracking is hydrogen-induced cracking, which is due to the existence of large amount of hydrogen, high impacting force, excessive flow rate, and the risk of ammonium chloride particle erosion at the U-bend. In order to alleviate the corrosion of ammonium chloride deposition, some improvement measures are put forward, such as raising the inlet temperature of the tube side to 215 °C and increasing the water injection by 30%, which play an important role in decreasing the formation of ammonium chloride in the heat exchange system.

Failure Analysis of Water-Wall Tubes in the High-Pressure Boiler

2014 ◽  
Vol 912-914 ◽  
pp. 456-459
Author(s):  
Na Xu ◽  
Jun Bo Shi ◽  
Yong De Li ◽  
Wei Min Guo ◽  
Xiao Feng Wu ◽  
...  
Keyword(s):  
High Pressure ◽  
Failure Analysis ◽  
Pitting Corrosion ◽  
Failure Process ◽  
Surface Damage ◽  
Metallographic Examination ◽  
Boiler Water ◽  
Corrosion Failure ◽  
Water Wall ◽  
Sulfide Corrosion

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.

Corrosion Failure Analysis of an SA210 Steel Used in High Pressure Evaporator Tube of the Gas Heat Recovery Boiler

2013 ◽  
Vol 791-793 ◽  
pp. 493-497
Author(s):  
Ling Shan Cen ◽  
Zhi Wu Wang ◽  
Liang Li ◽  
Yuan Mei Fei ◽  
Qian Qian Liu
Keyword(s):  
High Pressure ◽  
Failure Analysis ◽  
Heat Recovery ◽  
Steel Tube ◽  
Corrosion Products ◽  
Heat Recovery Boiler ◽  
Residual Water ◽  
Corrosion Failure Analysis ◽  
Corrosion Failure ◽  
Recovery Boiler

The corrosion failure analysis of an SA210 steel used in high pressure evaporator tube is conducted by XRD, SEM, OM. The result shows that the corrosion products in the inner wall of the steel tube is Fe3O4, mainly caused by the residual water in the evaporator tube corroding its inner wall with oxygen after the hydrostatic test of the boiler, finally leading to the corrosion leak of the tube.

Stress corrosion failure of high-pressure gas pipeline

2007 ◽  
Vol 14 (5) ◽  
pp. 801-809 ◽  
Author(s):  
F. Hasan ◽  
J. Iqbal ◽  
F. Ahmed
Keyword(s):  
High Pressure ◽  
Stress Corrosion ◽  
Gas Pipeline ◽  
Corrosion Failure

A study on the corrosion failure induced by the ammonium chloride deposition in a high-pressure air cooler system

2020 ◽  
Vol 112 ◽  
pp. 104529
Author(s):  
Xiaofei Liu ◽  
Aoqiang Duan ◽  
Jianxun Quan ◽  
Haozhe Jin ◽  
Chao Wang
Keyword(s):  
High Pressure ◽  
Ammonium Chloride ◽  
Corrosion Failure ◽  
Air Cooler ◽  
Chloride Deposition

Internal Corrosion of High-Pressure Boilers

1967 ◽  
Vol 89 (3) ◽  
pp. 378-394
Author(s):  
P. Goldstein ◽  
I. B. Dick ◽  
J. K. Rice
Keyword(s):  
High Pressure ◽  
Research Study ◽  
Test Tube ◽  
Progress Report ◽  
Test Facility ◽  
Boiler Water ◽  
Internal Corrosion ◽  
Corrosion Failure ◽  
Internal Surfaces ◽  
Study Results

This report is the second in a series of three describing the progress of “A Research Study on Internal Corrosion of High Pressure Boilers.” The first progress report, presented by H. A. Klein and J. K. Rice at the 1965 Annual Meeting of the ASME, describes the background, scope, and organization of the program as well as the test facility. This second progress report describes the results of the first half of the study. Results of tests with volatile, coordinated phosphate, and caustic boiler water treatment under conditions simulating a boiler with clean internal surfaces and one whose surfaces have been fouled with typical preboiler corrosion products, are included. Data relating to deposition and corrosion in the aforementioned environments are presented. The corrosion failure of a test tube due to “caustic gouging” and the discovery of an unusual effect of deposits on boiling characteristics are described.

scholarly journals Analysis of Multiphase Flow and Heat and Mass Transfer for Ammonium Chloride Crystallization of the High-Pressure Heat Exchanger in Hydrogenation Unit

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7754
Author(s):  
Jianwen Zhang ◽  
Yahui Zhao ◽  
Yan Li ◽  
Fan Zhang
Keyword(s):  
Mass Transfer ◽  
High Pressure ◽  
Heat Exchanger ◽  
Multiphase Flow ◽  
Gas Phase ◽  
Heat And Mass Transfer ◽  
Ammonium Chloride ◽  
Tube Bundle ◽  
Corrosion Failure ◽  
Petrochemical Enterprise

The corrosion failure of the high-pressure heat exchanger in a petrochemical enterprise was simulated. A multiphase flow and heat and mass transfer simulation shows that the vortex core with a higher gas phase content and lower temperature is the region of easy crystallization, located on both sides of the center of the tube. The crystallization process occurs in the gas phase. As the reaction progresses, the crystallization range spreads from the tube wall to the center of the tube bundle, and the inner diameter of the tube bundle decreases continuously. In Fluent, a user-defined function, based on the ammonium chloride crystallization reaction, is loaded. The results show that crystallization first occurs in the tube bundles on both sides of the center of the tube and that the corrosion is aggravated by the erosion wall surface of crystal particles at the elbow, which is consistent with the actual corrosion failure location.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

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.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

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