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

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.

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.

Investigation on the Flow Induced Erosion-Corrosion Failure of Hydrocracking Air Cooler Systems and Optimization Study

2009 ◽  
Author(s):  
Guofu Ou ◽  
Zhijian Zheng ◽  
Haozhe Jin ◽  
Jinzhe Bao
Keyword(s):  
Numerical Simulation ◽  
Multiphase Flow ◽  
Optimum Design ◽  
Similarity Theory ◽  
Corrosion Failure ◽  
Optimization Study ◽  
Mechanism Research ◽  
Erosion Corrosion ◽  
Control Research ◽  
Air Cooler

The flow induced erosion-corrosion of a hydrocracking reactor effluent air cooler (REAC) system normally occurs locally and abruptly, which leads to the high risk of unplanned shutdown and even catastrophic accidents. To study the typical failure cases induced by the high-sulfur and chloride-containing raw oil in the process of refining, numerical simulation of technical process and fluid dynamics parameters are performed on softwares of HYSYS and CFD, and the rules of multiphase flow erosion and ammonium salts deposition are analyzed. Analytical results are in good agreement with actual failure instance and thus the reliability of the predictive method is validated. A corrosion-control research system, consisting of mechanism research, numerical simulation, experimental verification and similarity theory correction, is established. The critical characteristics of multiphase flow deposition and erosion are obtained. And the system to control the flow induced erosion-corrosion, which can be widely applied in various conditions, is formed on the basis of “avoiding blockage and controlling erosion” conception. Moreover, this paper proposes an optimum design based on the degree of unbalancedness and a frame of the REAC Real-time Diagnosis Expert Software for guiding the optimum design. The method above will be beneficial to the promotion and modification of related criteria and regulations in the future.

NMR of Cl35 in Ammonium Chloride under High Pressure

1967 ◽  
Vol 22 (3) ◽  
pp. 927-927 ◽  
Author(s):  
Shoichi Ueda ◽  
Junkichi Itoh
Keyword(s):  
High Pressure ◽  
Ammonium Chloride

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.

scholarly journals Innovative Way to Decrease the Water Consumption of Direct Evaporative Air-Cooler

2020 ◽  
Vol 9 (3) ◽  
pp. 115-121
Keyword(s):  
Ammonium Chloride ◽  
Water Consumption ◽  
Salt Water ◽  
Primary Objective ◽  
Cooling Effect ◽  
Endothermic Reaction ◽  
Surrounding Environment ◽  
Water Separator ◽  
Salt Crystals ◽  
Air Cooler

In the present study the existing direct evaporative coolers (DEC) is modified in such a way that DEC consume less amount of water and provide better cooling effect. In desert area, water consumption by air cooler is a serious problem. Therefore, the present study addressed this issue and primary objective of the study is to minimize the consumption of water. For this purpose, the property of the endothermic reaction is utilized. There are few salts that produce endothermic reaction if it is diluted in water. Those salt crystals absorb heat from the surrounding environment (water) and ultimately the temperature of the overall solution gets reduced. This cold solution is then passed through honeycomb cooling pad, as a result more amount of air can be cooled using the same volume of water as compared to the traditional air-cooler. Ammonium Chloride (NH4Cl), Ammonium Nitrite (NH4NO3 ) salts satisfy the basic criteria for the endothermic reaction but NH4Cl will be more useful to use in the air-coolers, as Ammonium Nitrite is costlier and also hazardous. A salt water separator arrangement also attached with modified air-cooler which will help to regenerate Ammonium Chloride crystal from solution with the help of solar energy. In this study, firstly discussed about proposed design of an air-cooler system, which is able to nicely handle chemical solution. Then compared the study with experimental outcome which have been carried out with and without using salt. From the result it has been observed that modified design of air cooler has great potential to improve the traditional air cooler in terms of cooling effect and water consumption

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