scholarly journals THERMODYNAMIC ANALYSIS OF IRON OXIDES REDUCTION USING CARBON AND WATER VAPOUR

2019 ◽  
Vol 62 (5) ◽  
pp. 394-406
Author(s):  
Yu. S. Kuznetsov ◽  
O. I. Kachurina
Keyword(s):  
Water Vapor ◽  
Thermodynamic Analysis ◽  
Total Carbon ◽  
Isothermal Exposure ◽  
Carbon Gasification ◽  
Temperature Range ◽  
Reduction Of Iron ◽  
Co Dissociation ◽  
Full Reduction ◽  
Water Gas

Thermodynamic analysis was performed for complete reduction of iron oxide during heating the initial system «Fe3O4 (eo mol) – H2O (bo mol) – C (excess) » with isothermal exposure. By the nature of ongoing reactions, processes in the system can be divided into four stages. Carbon gasification by water vapor at temperatures below 880 K activates water gas reaction and CO dissociation to form black carbon. Composition of the resulting H2 – H2O – CO – CO2 gas mixture depends only on the temperature. The consumption of carbon at 880 K is ~0,4446 moles on 1 mole of water. Reduction of Fe3O4 to wustite FeO1+x with varying degrees of oxidation occurs in the temperature range 880 – 917 K. Hydrogen reduces oxide at temperatures above 888 K. The percentage part of a whole oxide Fe3O4 reduced by hydrogen into this temperature range increases from zero to ~63 %. The total number of Fe3O4, reduced to wustite at 917 K is ~123 moles for 1 mole of water. It is possible only with repeated regeneration of reductants CO and H2 according to the reactions of carbon gasification by water vapor and by dioxide CO2. The carbon expense is about 78 moles. Wustite FeO1.092 formed at 917 K can be reduced by monoxide CO only at temperatures of 917 – 955 K to wustite FeO1.054 with a lower degree of oxidation. Carbon is gasified only by dioxide CO2, the carbon expense is approximately 18 moles. When isothermal exposure is ~955 K, wustite is reduced to iron. Wustite can be reduced only by carbon monoxide. The carbon expense is approximately 257 mol. For full reduction of 123 mol of Fe3O4 in a mixture with an excess of carbon in a closed system at 1 atm, 1 mole of water is sufficient. The total carbon consumption is ~353 moles for obtaining 368 moles of Fe, or ~0.21 kg/kg iron.

scholarly journals Thermodynamic analysis of chromium reduction from oxide Cr2O3

2021 ◽  
Vol 63 (11-12) ◽  
pp. 935-945
Author(s):  
Yu. S. Kuznetsov ◽  
O. I. Kachurina
Keyword(s):  
Water Vapor ◽  
Gas Phase ◽  
Thermodynamic Analysis ◽  
Chromium Oxide ◽  
Reduction Rate ◽  
Oxidation Potential ◽  
Chromium Reduction ◽  
Heating Water ◽  
Increasing Temperature ◽  
Water Gas

Thermodynamic analysis of chromium reduction from its oxide in gas phase Н2 – Н2О – СО – СО2 in contact with carbon was performed. Oxidation potential (pO2 ) was determined by two nomograms in the coordinates and taking into account condition normalizations xH2O + xH2 + xCO2+ xCO = 1. In calculations, possible parameters of reduction of chromium from Cr2O3 oxide were determined by ratio of dissociation elasticity of the oxide and oxidation potential of the gas phase. In the СО – СО2 – С system, chromium is reduced at temperature of 1505 K if xCO > 0.9995. At this temperature, Cr2O3 compound is reduced in water gas of the following composition xH2 = 0.0186, xH2O = 0.28·10–4, xCO = 0.9809, xCO2 = 4.86·10–4, for which the oxidation potential is equal to dissociation elasticity of oxide With an increase in hydrogen concentration from 0.0186 to 0.99, oxidation potential of water gas in contact with carbon decreases by four orders of magnitude to This should lead to a significant increase in reduction rate. In such a gaseous atmosphere, it is possible to reduce chromium at temperature of 1230 K. It is technologically simple to obtain reducing water gas and at the lowest cost, for example, by heating water vapor in contact with carbon. It is shown that at temperature of 1500 K water gas is obtained with traces of Н2О and СО2 compounds with parameters xH2 = 0.4999, xCO = 0.4996,  Oxidizing potential of such a gas is less than that of chromium oxide, and this difference significantly increases with increasing temperature.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

Theoretical analysis and experiments for the carburization of vanadium-bearing hot metal

2018 ◽  
Vol 115 (2) ◽  
pp. 204
Author(s):  
Deng Ma ◽  
Wei Wu ◽  
Shifan Dai ◽  
Zhibin Liu
Keyword(s):  
Theoretical Analysis ◽  
Thermodynamic Analysis ◽  
Induction Furnace ◽  
Cost Effective ◽  
Pilot Scale ◽  
Hot Metal ◽  
Temperature Range ◽  
Vanadium Extraction ◽  
Low Nitrogen

In this study, the feasibility of the carburization of vanadium-bearing hot metal was first investigated by thermodynamic analysis. Next, three carburizers, namely a low-nitrogen carburizer, anthracite, and coke, were used for carburization of 500 g of vanadium-bearing hot metal at 1450 °C, 1500 °C, and 1550 °C, respectively. The carbon increments for the low-nitrogen carburizer, anthracite and coke followed decreasing order in the temperature range from 1450 °C to 1550 °C. Anthracite was the most cost-effective carburizer. Hence, anthracite is used in pilot-scale experiments of the vanadium-bearing hot metal (100 kg and 200 kg). Finally, vanadium extraction experiments of the vanadium-bearing hot metal were carried out in a top-bottom-combined blowing induction furnace. It is proved that the average superheat degree of semi-steel increases from 100 °C to 198 °C by the carburization of vanadium-containing hot metal.

Water vapor sorption on Marcellus shale: measurement, modeling and thermodynamic analysis

Fuel ◽  
2017 ◽  
Vol 209 ◽  
pp. 606-614 ◽  
Author(s):  
Xu Tang ◽  
Nino Ripepi ◽  
Katherine A. Valentine ◽  
Cigdem Keles ◽  
Timothy Long ◽  
...  
Keyword(s):  
Water Vapor ◽  
Thermodynamic Analysis ◽  
Marcellus Shale ◽  
Water Vapor Sorption ◽  
Vapor Sorption

scholarly journals Thermodynamic analysis of copper(I) sulfide chlorination by calcium chloride in the presence of oxygen

1999 ◽  
Vol 64 (5-6) ◽  
pp. 365-374 ◽  
Author(s):  
Rajko Vracar ◽  
Katarina Cerovic
Keyword(s):  
Calcium Chloride ◽  
Thermodynamic Analysis ◽  
Chemical Reactions ◽  
Phase Stability ◽  
Log P ◽  
Temperature Range ◽  
Stability Diagrams

This paper presents a thermodynamic analysis of possible, but insufficiently studied, chemical reactions occurring during the chlorination of copper(I) sulfide by calcium chloride in the presence of oxygen. It formed the basis for assessing the probability and priority of their occurrence. Phase stability diagrams have been plotted for the Cu-S-O-Cl system in the coordinates log p(S2)-log p(O2)-log p(Cl2) in the temperature range from 473 to 773 K.

scholarly journals A Review of Pyrolisis of Eceng Gondok (Water hyacinth) for Liquid Smoke

2018 ◽  
Vol 73 ◽  
pp. 05010
Author(s):  
Rita Dwi Ratnani ◽  
Widiyanto
Keyword(s):  
Acetic Acid ◽  
Water Vapor ◽  
Activated Charcoal ◽  
Water Hyacinth ◽  
Combustion Process ◽  
Pyrolysis Process ◽  
Temperature Range ◽  
Liquid Smoke ◽  
16Th World ◽  
Co Gas

The growth of eceng gondok (Water hyacinth) in Rawa Pening Lake showed rapid increase.. Based on the mandate of the National Lake conference in Bali and the 16th World Lake Conference, Rawa Pening is one of the fifteen national lakes which need to be treated for its conservation. Reducing number of eceng gondok plants is one of the alternatif. However, further processing is required to treat the waste of eceng gondok. One attempt is to convert eceng gondok (water hyacinth) into liquid smoke product. This article reviewes the potency of eceng gondok for liquid smoke through pyrolisis method. The liquid smoke can be used for various applications such as preservatives, antioxidants, biopesticides and perisa disinfectants. Pyrolysis is a combustion process in the absence of oxygen to produce liquid and charcoal activated charcoal products called activated charcoal. The pyrolysis process is generally carried out at a temperature range between 200-700 °C. The pyrolysis process is one of the methods chosen in order to strive for development that suppresses the formation of CO gas but releases water vapor. Pyrolysis at a temperature of 300-700 ° C, produces the most dominant compounds 1.6 Anhyro-beta-d-glucopyranose, phenol, and acetic acid. The reaction that occurs during pyrolysis of this temperature is the release of water vapor instead of carbon gas so that it is safe for the environment. The discussion on this article focused on the production of liquid smoke from eceng gondok biomass.

scholarly journals Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra

2013 ◽  
Vol 6 (2) ◽  
pp. 263-274 ◽  
Author(s):  
C. Frankenberg ◽  
D. Wunch ◽  
G. Toon ◽  
C. Risi ◽  
R. Scheepmaker ◽  
...  
Keyword(s):  
Water Vapor ◽  
Hydrological Cycle ◽  
Time Frame ◽  
Global Scale ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Validation Dataset ◽  
Spatial Correlations ◽  
Vertical Column ◽  
Shortwave Infrared

Abstract. Remote sensing of the isotopic composition of water vapor can provide valuable information on the hydrological cycle. Here, we demonstrate the feasibility of retrievals of the relative abundance of HDO (the HDO/H2O ratio) from the Japanese GOSAT satellite. For this purpose, we use high spectral resolution nadir radiances around 6400 cm−1 (1.56 μm) to retrieve vertical column amounts of H2O and HDO. Retrievals of H2O correlate well with ECMWF (European Centre for Medium-Range Weather Forecasts) integrated profiles (r2 = 0.96). Typical precision errors in the retrieved column-averaged deuterium depletion (δD) are 20–40‰. We compare δD against a TCCON (Total Carbon Column Observing Network) ground-based station in Lamont, Oklahoma. Using retrievals in very dry areas over Antarctica, we detect a small systematic offset in retrieved H2O and HDO column amounts and take this into account for a bias correction of δD. Monthly averages of δD in the June 2009 to September 2011 time frame are well correlated with TCCON (r2 = 0.79) and exhibit a slope of 0.98 (1.23 if not bias corrected). We also compare seasonal averages on the global scale with results from the SCIAMACHY instrument in the 2003–2005 time frame. Despite the lack of temporal overlap, seasonal averages in general agree well, with spatial correlations (r2) ranging from 0.62 in September through November to 0.83 in June through August. However, we observe higher variability in GOSAT δD, indicated by fitted slopes between 1.2 and 1.46. The discrepancies are likely related to differences in vertical sensitivities but warrant further validation of both GOSAT and SCIAMACHY and an extension of the validation dataset.

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