A model to predict erosion on mild steel surfaces impacted by boiler fly ash particles

Wear ◽  
2004 ◽  
Vol 257 (5-6) ◽  
pp. 612-624 ◽  
Author(s):  
J.G Mbabazi ◽  
T.J Sheer ◽  
R Shandu
Volume 1 ◽  
2004 ◽  
Author(s):  
John G. Mbabazi ◽  
Thomas J. Sheer

Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the downstream flow path. This paper describes research into fly ash impingement erosion on such surfaces, with particular reference to the heat transfer plates in rotary regenerative air heaters. The effect of the ash particle impact velocity and impact angle on the erosive wear of mild steel surfaces was determined through experimental investigations, using three different power station ash types. The experimental data were used to calibrate a fundamentally-derived model for the prediction of erosion rates. This erosion model was incorporated into a particle-tracking CFD flow simulation of the ash-laden flue gas flow through the complex channels between corrugated air heater plates. The predicted erosion rates were compared with measured erosion rates obtained using a large accelerated-erosion test facility located at a power station. Good agreement was obtained, the predictions generally being within 20 percent of the measured values.


2007 ◽  
Vol 49 (5) ◽  
pp. 2270-2288 ◽  
Author(s):  
Robert Jeffrey ◽  
Robert E. Melchers
Keyword(s):  

2016 ◽  
Vol 12 (1) ◽  
pp. 27
Author(s):  
Maria Erna ◽  
Emriadi Emriadi ◽  
Admin Alif ◽  
Syukri Arief

The thermodynamic properties and characterizations of corrosion inhibition of chitosan nano-particles on the surface of mild steel in peat water media had been studied using weight loss method at temperatures of 30 - 50 <sup>o</sup>C. Steel surfaces were characterized by FT-IR spectra and SEM-EDS morphology photos. The research found that the value of DG<sup>o </sup>approaching -40 kJmol<sup>-</sup><sup>1</sup>. The negative value of Gibbs free energy shows that the adsorption of inhibitor molecules on the surface of mild steel was achemisorption and it occurred spontaneously. Meanwhile, the values of DH<sup>o </sup>is also negative confirming that the adsoprtion of inhibitor molecules is an exothermic process. The value of DS<sup>o </sup>obtained is positive, it indicates hat the inhibitor molecules were adsorbed spontaneously on the mild steel surface. The analysis on mild steel surfaces hows that the nano-particle chitosan was adsorbed on the steel surface to form the complex compounds.


1993 ◽  
Vol 34 (7) ◽  
pp. 1055-1081 ◽  
Author(s):  
A. Askey ◽  
S.B. Lyon ◽  
G.E. Thompson ◽  
J.B. Johnson ◽  
G.C. Wood ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2424 ◽  
Author(s):  
Bao-guo Fan ◽  
Li Jia ◽  
Yan-lin Wang ◽  
Rui Zhao ◽  
Xue-song Mei ◽  
...  

In order to obtain the adsorption mechanism and failure characteristics of CO2 adsorption by potassium-based adsorbents with different supports, five types of supports (circulating fluidized bed boiler fly ash, pulverized coal boiler fly ash, activated carbon, molecular sieve, and alumina) and three kinds of adsorbents under the modified conditions of K2CO3 theoretical loading (10%, 30%, and 50%) were studied. The effect of the reaction temperature (50 °C, 60 °C, 70 °C, 80 °C, and 90 °C) and CO2 concentration (5%, 7.5%, 10%, 12.5%, and 15%) on the adsorption of CO2 by the adsorbent after loading and the effect of flue gas composition on the failure characteristics of adsorbents were obtained. At the same time, the microscopic characteristics of the adsorbents before and after loading and the reaction were studied by using a specific surface area and porosity analyzer as well as a scanning electron microscope and X-ray diffractometer. Combining its reaction and adsorption kinetics process, the mechanism of influence was explored. The results show that the optimal theoretical loading of the five adsorbents is 30% and the reaction temperature of 70 °C and the concentration of 12.5% CO2 are the best reaction conditions. The actual loading and CO2 adsorption performance of the K2CO3/AC adsorbent are the best while the K2CO3/Al2O3 adsorbent is the worst. During the carbonation reaction of the adsorbent, the cumulative pore volume plays a more important role in the adsorption process than the specific surface area. As the reaction temperature increases, the internal diffusion resistance increases remarkably. K2CO3/AC has the lowest activation energy and the carbonation reaction is the easiest to carry out. SO2 and HCl react with K2CO3 to produce new substances, which leads to the gradual failure of the adsorbents and K2CO3/AC has the best cycle failure performance.


2000 ◽  
Vol 42 (7) ◽  
pp. 1197-1211 ◽  
Author(s):  
C-O.A. Olsson ◽  
P. Agarwal ◽  
M. Frey ◽  
D. Landolt

2011 ◽  
Vol 32 (4) ◽  
pp. 255-266 ◽  
Author(s):  
Rafał Kobyłecki

Unburned carbon in the circulating fluidised bed boiler fly ash The paper describes the results of various actions and industrial tests conducted in order to decrease the content of unburned carbon in the fly ash of a circulating fluidised bed combustor (CFBC). Several attempts to improve the situation were made and the effects of several parameters on the unburned carbon content in the fly ash were investigated (e.g. bed temperature, cyclone separation efficiency, fuel particle size distribution, boiler hydrodynamics, grid design, and fuel data). Unfortunately, no satisfactory solution to these problems was found. Probably, apart from attrition and char fragmentation, additional factors also contributed to the formation of unburned carbon in the CFBC fly ash.


Wear ◽  
1995 ◽  
Vol 188 (1-2) ◽  
pp. 40-48 ◽  
Author(s):  
Bu-Qian Wang

Author(s):  
Thomas B Scott ◽  
Geoffrey C Allen ◽  
Peter J Heard ◽  
Andrew C Lewis ◽  
Darren F Lee
Keyword(s):  

The observation of uranium remediation from groundwater onto mild-steel surfaces is reported. Mechanisms for uranium immobilization are proposed.


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