Effect of sulfur removal on Al2O3 scale adhesion

1991 ◽  
Vol 22 (3) ◽  
pp. 739-752 ◽  
Author(s):  
James L. Smialek
Keyword(s):  
Sulfur Removal ◽  
Al2o3 Scale ◽  
Scale Adhesion

Effect of sulfur removal on scale adhesion to PWA 1480

1995 ◽  
Vol 26 (2) ◽  
pp. 427-435 ◽  
Author(s):  
J. L. Smialek ◽  
B. K. Tubbs
Keyword(s):  
Sulfur Removal ◽  
Scale Adhesion

scholarly journals Origins of a Low-Sulfur Superalloy Al2O3 Scale Adhesion Map

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 60
Author(s):  
James Smialek
Keyword(s):  
Sulfur Content ◽  
Cyclic Oxidation ◽  
Reactive Element ◽  
Al2o3 Scale ◽  
Sulfur Segregation ◽  
Scale Adhesion ◽  
2Nd Generation ◽  
No Weight Loss ◽  
Transitional Behavior ◽  
Low Sulfur

Low-sulfur single-crystal Ni-base superalloys have demonstrated excellent cyclic oxidation resistance due to improved Al2O3 scale adhesion. This derives from preventing deleterious interfacial sulfur segregation that occurs at common ppm levels of S impurity. Multiple hydrogen-annealing desulfurization treatments were employed to produce a continuum of levels demonstrating this oxidative transition, using 1 h cyclic oxidation at 1100 °C for 500 h to 1000 h. The sulfur content was determined by glow discharge mass spectrometry. The complete gravimetric database of 25 samples is revealed and correlated with sulfur content. Maximum adhesion (i.e., no weight loss) was achieved at ≤ 0.3 ppmw S, significant spallation (20–30 mg/cm2) above 2 ppmw, with transitional behavior between 0.3 and 2 ppmw S. A map suggested that adhesion was enabled when the total sulfur reservoir was less than one S atom per Ni interface atom. Equilibrium models further suggest that segregation may be minimized (~1% at 0.2 ppmw bulk), regardless of section thickness. 1st order adhesion effects have thus been demonstrated for PWA 1480 having no Y, Zr, or Hf reactive element dopants and no possibility of confounding reactive element effects. The results are compared with 2nd generation PWA 1484, Rene’N5, N6, and CMSX-4® SLS, all having Hf dopants.

scholarly journals Removal of Impurities from Shungite Via a Combination of Physical and Chemical Treatments

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 245
Author(s):  
Toyohisa Fujita ◽  
Taichi Aoki ◽  
Josiane Ponou ◽  
Gjergj Dodbiba ◽  
Chunlin He ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Sulfur Removal ◽  
Nitrilotriacetic Acid ◽  
Microwave Treatment ◽  
Magnetic Flux Density ◽  
High Gradient Magnetic Separation ◽  
Chemical Leaching ◽  
Inorganic Acids ◽  
Mineralogical Study ◽  
Physical And Chemical

This study investigated the removal of sulfur and iron from shungite rocks through different methods after fine grinding: flotation, magnetic separation, microwave treatment, and chemical leaching. In this work, first, a mineralogical study of shungite was conducted. The carbon, silica, iron, and sulfur compositions in the as-received shungite were 45.4%, 38.3%, 4.6%, and 2.4%, respectively. In flotation, a sulfur grade of 1.4% was obtained. In the wet high-gradient magnetic separation at a magnetic flux density of 1 tesla, the iron and sulfur grades in the nonmagnetic fraction were 2.8% and 1.9%, respectively. Furthermore, the sulfur reduced to 0.2% by the 9 min microwave irradiation. In addition, chemical leaching using chelating reagents and inorganic acids was utilized to remove iron and sulfur. Nitrilotriacetic acid (NTA) could reduce the iron and sulfur grades to 2.0% and 0.9%, respectively. For leaching using reverse aqua regia, the iron and sulfur grades were reduced to 0.9% and 0.23%, respectively. For leaching using a 6N HCl with H2O2 aqueous solution, the iron and sulfur grades were reduced to 0.8% and 0.34%, respectively. Overall, chemical leaching using HCl with H2O2 was the most effective for iron and sulfur removal from shungite.

Design of a Reaction Protocol for Decoupling Sulfur Removal and Thermal Aging Effects during Desulfation of Pt−BaO/Al2O3Lean NOxTrap Catalysts

2007 ◽  
Vol 46 (9) ◽  
pp. 2735-2740 ◽  
Author(s):  
Do Heui Kim ◽  
Ya-Huei Chin ◽  
George Muntean ◽  
Aleksey Yezerets ◽  
Neal Currier ◽  
...  
Keyword(s):  
Thermal Aging ◽  
Sulfur Removal ◽  
Aging Effects

Efficient Oxidative Desulfurization (ODS) of Commercial Diesel with TBHP under Mild Conditions Catalyzed by Polymolybdates Supported on Al2O3

2015 ◽  
Vol 1107 ◽  
pp. 341-346
Author(s):  
Wan Nazwanie Wan Abdullah ◽  
Rusmidah Ali ◽  
Wan Azelee Wan Abu Bakar
Keyword(s):  
Sulfur Content ◽  
Research Work ◽  
Sulfur Removal ◽  
Oxidative Desulfurization ◽  
Catalyst System ◽  
Impregnation Method ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Alternative Method ◽  
Tert Butyl Hydroperoxide

Due to the low specifications for sulfur content in diesel, a lot of research work are been conducted to develop alternative method for desulfurization. Catalytic oxidative desulfurization (Cat-ODS) has been found to be an alternative method to replace a conventional method which is hydrodesulfurization.New catalyst formulation using tert-butyl hydroperoxide polymolybdate based catalyst system was investigated in this research utilizing tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdate supported alumina catalysts were prepared using wet impregnation method, ageing at ambient room temperature for 24 hours and followed by calcination process. A commercial diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by gas chromatography-flame photometric detector (GC-FPD). The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 35 ppmw under mild condition followed by solvent extraction. From catalytic testing, Mo-Al2O3 calcined at 500°C was revealed as the most potential catalyst which gave 92% of sulfur removal.

scholarly journals Technology Solutions: Cutting the cost of sulfur removal

2003 ◽  
Vol 37 (17) ◽  
pp. 319A-320A ◽  
Author(s):  
Britt E. Erickson
Keyword(s):  
Sulfur Removal ◽  
The Cost

Sulfur Removal from Spent Ladle Refining Furnace Slag at High Temperature

2021 ◽  
Vol 52 (2) ◽  
pp. 590-593
Author(s):  
Liushun Wu ◽  
Kunlong Liu ◽  
Wei Xu ◽  
Jue Wang ◽  
Haichuan Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Sulfur Removal ◽  
Ladle Refining ◽  
Furnace Slag

Sulfhydryl groups as potential biomarkers of water pollution

2021 ◽  
Author(s):  
Chourouk Romdhani ◽  
Zahrah Alhalili ◽  
Soumaya Elarbaoui ◽  
Moez Smiri
Keyword(s):  
Biological Treatment ◽  
Sulfur Removal ◽  
Thiol Group ◽  
Major Elements ◽  
Mineral Elements ◽  
Group 3 ◽  
Mineral Pollution ◽  
Potential Biomarkers

Abstract Thiols represent a source of environmental pollution especially wastewater. The present work aims to evaluate the degradation of sulfur in two biological treatment plants in Tunisia: conventional plant of Rades Malienne, and vertical and horizontal flow from the Grombalia plant. We analyzed (1) wastewater properties, (2) the hydrosulfur (thiol) group, (3) membrane processes ultrafiltration technique and (4) characterization of the quality of wastewater from different plants. We used ultrafiltration membrane assisted ZnO and TiO2 NPs application on real effluents from different biological treatment plants. STEP1 is found to be more loaded with sulphur. Application of AC-ZnO membrane gives 99.07% and 99.55% of sulfur removal from wastewater of STEP1 and STEP3. STEP3 is 50 times less charged on sulfur than STEP1. We suggested that when the sulphur content is high, this leads to an increase in mineral elements. This could be explained by the interactions between thiols and the major elements that cause mineral pollution.

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