Understanding the Thermochemical Process of H 2O-Steelmaking Slags Reaction: Iron Distribution, Hydrogen Generation and Phase Transformations

2021 ◽  
Author(s):  
Peng Li ◽  
Xiangyang Li ◽  
Hongwei Guo ◽  
Bingji Yan ◽  
Dong Chen ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Hydrogen Generation ◽  
Iron Distribution ◽  
Steelmaking Slags ◽  
Thermochemical Process

Hydrogen Generation Using the Modular Helium Reactor

2004 ◽  
Author(s):  
Matt Richards ◽  
Arkal Shenoy
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Chemical Reactions ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Hybrid Process ◽  
Thermochemical Process ◽  
Process Heat ◽  
Splitting Water

Process heat from a high-temperature nuclear reactor can be used to drive a set of chemical reactions, with the net result of splitting water into hydrogen and oxygen. For example, process heat at temperatures in the range 850°C to 950°C can drive the sulfur-iodine (SI) thermochemical process to produce hydrogen with high efficiency. Electricity can also be used to split water, using conventional, low-temperature electrolysis (LTE). An example of a hybrid process is high-temperature electrolysis (HTE), in which process heat is used to generate steam, which is then supplied to an electrolyzer to generate hydrogen. In this paper we investigate the coupling of the Modular Helium Reactor (MHR) to the SI process and HTE. These concepts are referred to as the H2-MHR. Optimization of the MHR core design to produce higher coolant outlet temperatures is also discussed.

Modification of Phosphorous Enrichment Behaviours in Steelmaking Slags Based on Phase Transformations

JOM ◽  
2021 ◽  
Author(s):  
Yongqi Sun ◽  
Mao Chen ◽  
Xiaodong Ma ◽  
Zhixing Zhao ◽  
Tim Evans ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Steelmaking Slags

Tensile Deformation of Alloy-22 at Ambient and Elevated Temperatures

2007 ◽  
Author(s):  
Rama S. Koripelli ◽  
Ajit K. Roy
Keyword(s):  
Electron Microscopy ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Hydrogen Generation ◽  
Tensile Deformation ◽  
Dynamic Strain ◽  
Transmission Electron ◽  
Thermochemical Process ◽  
Alloy 22 ◽  
Increasing Temperature

Significant efforts are in progress to identify and characterize the tensile properties of structural materials for application in hydrogen generation using a thermochemical process known as the sulfur-iodine cycle. Austenitic Alloy-22 has been evaluated for its tensile properties at temperatures ranging from ambient to 1000°C. As expected, the tensile strength was gradually decreased with increasing temperature due to the ease of plastic deformation at these temperatures. However, the failure strain gradually decreased from room temperature to 600°C, possibly due to the occurrence of a phenomenon known as dynamic strain aging. Transmission electron microscopy revealed maximum dislocation density at 600°C. Fractographic evaluation of the tested specimens by scanning electron microscopy showed dimpled microstructures at the primary fracture surface indicating ductile failures. However, at higher temperatures intergranular brittle failures were observed.

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

1980 ◽  
Vol 38 ◽  
pp. 340-341
Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Phase Transformations ◽  
Applied Stress ◽  
Structural Changes ◽  
Microscopical Investigation ◽  
Temperature Range ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Diffraction Effects ◽  
Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

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