Study of Metals Erosion in High Temperature Coal Gas Streams

1980 ◽  
Vol 102 (1) ◽  
pp. 148-152 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
J. Ramachandran

In order to provide the basis for alloy selection in future turbines using pulverized coal, an investigation is undertaken to obtain a basic understanding of the mechanisms of erosion at high temperatures. The test equipment has been designed to simulate the aerodynamic and thermodynamic conditions in the turbine. This facility has the capability of providing between ambient and a 1093°C (2000°F) environment temperature for erosion testing of various materials. The effects of high temperature on the erosion rate was determined and the test results from 304 stainless steel alloy are presented.

Author(s):  
W. Tabakoff ◽  
T. Wakeman

Gas turbine engines operating in dusty environments are exposed to severe erosion, especially the compressor and the turbine components. Predicting erosion in rotating machinery is a very complex problem. In order to provide the basis for alloy selection in future turbines using pulverized coal, an investigation is undertaken to obtain a basic understanding of the mechanisms of erosion at high temperatures. For this purpose, a test facility has been designed to simulate the aerodynamic and thermodynamic conditions in the turbine. The effects of high temperature on the erosion rate for different alloys are experimentally determined and the results obtained are presented in this paper. The findings are very important in predicting erosion rate for future turbomachinery exposed to particulate flows.


Author(s):  
M. Chomiak ◽  
J. Trawczyński ◽  
M. Zawadzki

AbstractZn–Ti–Co(Ni) sorbents for H2S removal from model hot coal were prepared and characterized. Effects of cobalt (Co) and nickel (Ni) on the sorbents texture, structure, H2S sorption capacity and regeneration properties were determined. TiO2 formed mixed metal oxides with CoO and NiO in the fresh sorbents, while TiO2 and nanocrystalline sulfides of Zn, Co, Ni were found in sulphided ones. The oxidative regeneration of sulphided sorbents re-formed mixed oxides. Sorption capacity of studied materials increased along with an increase of the amount of added Co (Ni) and also with the number of work cycles. Co-doped Zn–Ti materials adsorbed up to 244% more sulfur than these of Zn–Ti, while Ni-doped materials adsorbed ca. twice more H2S than the corresponding Co-doped sorbents. The addition of Co (Ni) decreased the temperature of ZnS oxidation. The catalytic effect of the Co (Ni) oxides on the oxidation of ZnS was suggested.


2001 ◽  
Vol 357-360 ◽  
pp. 1241-1244 ◽  
Author(s):  
M. Däumling ◽  
C.N. Rasmussen ◽  
F. Hansen ◽  
D.W.A. Willén ◽  
O.E. Schuppach ◽  
...  

2005 ◽  
Vol 19 (4) ◽  
pp. 1606-1610 ◽  
Author(s):  
Yili Li ◽  
Jian Li ◽  
Yuquan Jin ◽  
Youqing Wu ◽  
Jinsheng Gao

2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.


2015 ◽  
Vol 830-831 ◽  
pp. 191-194
Author(s):  
M. Venkateswara Rao

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.


1996 ◽  
Vol 35 (5) ◽  
pp. 1487-1495 ◽  
Author(s):  
A. G. J. van der Ham ◽  
A. B. M. Heesink ◽  
W. Prins ◽  
W. P. M. van Swaaij

Sign in / Sign up

Export Citation Format

Share Document