scholarly journals A FactsSage Simulation Study on the Interaction of Synthetic Petcoke Slags with Alumina Crucibles

Fuels ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 48-70
Author(s):  
Kashyap Karri ◽  
Shubhadeep Banik ◽  
Sarma V. Pisupati
Keyword(s):  
Inverse Correlation ◽  
High Alumina ◽  
Slag Viscosity ◽  
Reliable Operation ◽  
Crucible Material ◽  
Inorganic Species ◽  
Initial Content ◽  
Entrained Flow Gasifiers ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Calculations

In entrained flow gasifiers, inorganic species in solid fuels are converted to slag, which flows continuously along the gasifier’s refractory lining. Slag viscosity is critical for its continuous flow and, consequently, reliable operation of the gasifier. Viscosity of synthetic petcoke ash was measured in a high temperature viscometer (up to 1500 °C) using high alumina crucibles. Crucible material was found to dissolve in slag, causing thinning and leading to formation of holes on the walls. To explain this dissolution, thermodynamic equilibrium calculations were performed in FactSage™ (Thermfact/CRCT, Montreal, QC, Canada and GTT-Technologies, Aachen, Germany) using different synthetic petcoke ash compositions in 100% H2, 5% H2/ 95% N2, 69.5% CO/30.5% CO2, and 100% O2 atmospheres. An inverse correlation was found between crucible dissolution and alumina content in the slag. Rates of dissolution of alumina from crucible into slag varied significantly in the different atmospheres. The correlation was validated experimentally by heating six synthetic slags with varying compositions to 1500 °C in 5% H2/N2 (to simulate viscometer’s atmosphere) gas. SEM-EDS analysis of the samples confirmed that the sample with lower initial content of alumina in the slag showed higher amounts of aluminum at the slag–crucible interface. Additions of alumina in the synthetic petcoke ash (containing up to 49.74% V2O5) mitigated crucible dissolution.

scholarly journals Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

2007 ◽  
Vol 7 (3) ◽  
pp. 9203-9233 ◽  
Author(s):  
C. Fountoukis ◽  
A. Nenes ◽  
A. Sullivan ◽  
R. Weber ◽  
T. VanReken ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mexico City ◽  
Thermodynamic Equilibrium ◽  
Phase State ◽  
Molar Ratio ◽  
Inorganic Species ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Model ◽  
Thermodynamic Equilibrium Calculations

Abstract. Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. Semi-volatile partitioning equilibrates on a timescale between 6 and 20 min. When the aerosol sulfate-to-nitrate molar ratio is less than 1, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as "equivalent sodium" (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations are required to accurately predict the partitioning and phase state of aerosols.

scholarly journals Thermodynamic Equilibrium Calculations on the Oxidation Behavior of the Mo-Ru-Rh-Pd Alloys

2012 ◽  
Vol 11 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Yuji OHISHI ◽  
Ken KUROSAKI ◽  
Tohru SUGAHARA ◽  
Aikebaier YUSUFU ◽  
Yusuke MASAHIRA ◽  
...  
Keyword(s):  
Thermodynamic Equilibrium ◽  
Oxidation Behavior ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Calculations

scholarly journals Influence of Al on Evolution of the Inclusions in Ti-Bearing Steel with Ca Treatment

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 104 ◽  
Author(s):  
Yandong Li ◽  
Tongsheng Zhang ◽  
Huamei Duan
Keyword(s):  
Bearing Steel ◽  
Chemical Compositions ◽  
Calcium Treatment ◽  
X Ray ◽  
Inclusion Formation ◽  
Liquid Phases ◽  
Before And After ◽  
Equilibrium Calculations ◽  
Good Agreement ◽  
Thermodynamic Equilibrium Calculations

Experimental simulations of steelmaking with different amounts of aluminum were achieved in the tube furnace at 1873 K and field scanning electron microscopy and energy dispersive X-ray spectroscopy (FE-SEM and EDX) were employed to explore the characteristics of the inclusions in Ti-bearing steel during the calcium treatment process. It was found that morphologies, chemical compositions, and the size distribution of the inclusions were obviously different before and after calcium treatment. The calcium addition need be carefully considered regarding the mass fraction of aluminum with the purpose of modifying the solid inclusions to liquid phases. The thermodynamic analysis of inclusion formation in the Al–Ti–Ca–O system at 1873 K was conducted, as well as transformation behaviors of inclusions including all types of solid inclusions and liquid phases during solidification. The thermodynamic equilibrium calculations are in good agreement with experimental data, which can be used to estimate inclusion formation in Ti-bearing steel.

Thermodynamic equilibrium calculations of the volatilization and condensation of inorganics during wood gasification

Fuel ◽  
2013 ◽  
Vol 107 ◽  
pp. 269-281 ◽  
Author(s):  
K. Froment ◽  
F. Defoort ◽  
C. Bertrand ◽  
J.M. Seiler ◽  
J. Berjonneau ◽  
...  
Keyword(s):  
Thermodynamic Equilibrium ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Calculations

scholarly journals Application of optical basicity to viscosity of high alumina blast furnace slags

2010 ◽  
Vol 46 (1) ◽  
pp. 41-49 ◽  
Author(s):  
D. Ghosh ◽  
V.A. Krishnamurthy ◽  
S.R. Sankaranarayanan
Keyword(s):  
Blast Furnace ◽  
Chemical Composition ◽  
Physical Property ◽  
Optical Basicity ◽  
Alumina Content ◽  
High Alumina ◽  
Furnace Productivity ◽  
Slag Viscosity ◽  
Limited Information ◽  
Weight Percentage

The composition and properties of blast furnace slags greatly affect the furnace productivity and the quality of hot metal produced. Viscosity is an important physical property of slags, strongly influenced by the chemical composition, structure and the temperature. Experimental measurement of slag viscosity requires high temperature equipment and is time consuming. Therefore, chemical parameters are used to identify trends in viscosity as function of chemical composition. Limited information is available for High Alumina Blast Furnace Slags, since much of the open literature deals with Low Alumina Slags, with alumina content less than 15 weight percentage. High Alumina slags (alumina content in the range of 15% to 30%) are predominantly encountered in Indian Blast Furnaces. It appears that these slags have higher viscosity and lower sulphide capacity than the low alumina slags. The effect of chemical composition / ionic structure on viscosity has been interpreted in this work, using the chemical parameter of optical basicity. Data reported in the literature have been used, along with the values of liquidus temperature, for high alumina slags. Three slag systems, i.e., CaO-Al2O3-SiO2, CaO-Al2O3-SiO2-MgO and CaO-Al2O3-SiO2-MgO-TiO2 have been considered in this work. The trends observed are discussed in the paper.

scholarly journals Vaporization of Vanadium Pentoxide from CaO-SiO2-VOx Slags During Alumina Dissolution

2021 ◽  
Author(s):  
Tetiana Shyrokykh ◽  
Xingwen Wei ◽  
Seshadri Seetharaman ◽  
Olena Volkova
Keyword(s):  
Surface Tension ◽  
Gas Phase ◽  
Vanadium Pentoxide ◽  
Molten Slag ◽  
Slag Viscosity ◽  
Crucible Material ◽  
Gas Treatment ◽  
Treatment Regimens ◽  
High Vapor ◽  
Alumina Dissolution

AbstractThe vaporization of vanadium pentoxide from CaO-SiO2-VOx ternary slags using different gas treatment regimens and parallel vacuum gas extirpation to treat V-bearing slags at 1873 K has been developed in the present study. The novelty of the present study is to monitor the effect of parallel alumina dissolution on the vaporization phenomenon. Vanadium pentoxide has high vapor pressure at the temperatures over 1500 K. When CaO-SiO2-VOx ternary slags, kept in dense alumina crucibles, are injected with oxygen, V2O5 gas bubbles are formed which are forced out by using vacuum extirpation. The vanadium pentoxide could be then collected in the exhaust gases. The mechanism of the process phenomenon is described as the formation of V2O5 gas phase resulting from the oxidation of the lower-valent oxides present in the slag. This gas phase would form microbubbles in the molten slag bulk phase due to low surface tension between the gas phase and the slag, thereby increasing the contact surface. At the same time, the crucible material would dissolve in the slag causing an increase in the slag viscosity. Due to the high slag viscosity of the bulk slag, these microbubbles formed would have difficulty in coalescing and reaching the slag surface. The escaping of the bubbles into the gas phase is enabled by the vacuum extirpation.

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