Climate Change, Carbon Capture, Storage and CO2 Mineralisation Technologies

This Special Issue delivered 16 scientific papers, with the aim of exploring the application of carbon capture and storage technologies for mitigating the effects of climate change. Special emphasis has been placed on mineral carbonation techniques that combine innovative applications to emerging problems and needs. The aim of this Special Issue is to contribute to improved knowledge of the ongoing research regarding climate change and CCS technological applications, focusing on carbon capture and storage practices. Climate change is a global issue that is interrelated with the energy and petroleum industry

Process Modeling in Pyrometallurgical Engineering

The Special Issue presents almost 40 papers on recent research in modeling of pyrometallurgical systems, including physical models, first-principles models, detailed CFD and DEM models as well as statistical models or models based on machine learning. The models cover the whole production chain from raw materials processing through the reduction and conversion unit processes to ladle treatment, casting, and rolling. The papers illustrate how models can be used for shedding light on complex and inaccessible processes characterized by high temperatures and hostile environment, in order to improve process performance, product quality, or yield and to reduce the requirements of virgin raw materials and to suppress harmful emissions

Syntheses of ternary oxyhydrates and oxides in the calcium-uranium system: Stoichiometric influences on their structural affinity, precipitation mechanisms, and solid-state transformations

Calcium uranyl(VI) oxyhydrates and uranates are structurally related U(VI)-phases featuring uranium oxo-polyhedral sheets, with calcium ions occupying the interlayer. Both coordination environments appear throughout the nuclear fuel-cycle as alteration products, colloids, and sorption complexes. However, concerted studies spanning the aqueous precipitation mechanisms of uranyl(VI) oxyhydrates, their solid-state transformations, and structural relationships with uranates, have hitherto remained largely unexplored. A series of calcium-based uranyl(VI) oxyhydrates were precipitated via alkalisation of aqueous precursor solutions in titration and batch reactions. The bulk stoichiometric ratio of calcium to uranium (Ca/U) of precipitates was varied by modifying precursor stoichiometry, reaction temperature, or extraction pH. The rate of precipitation and its dependency on temperature was quantified in-situ using a quartz crystal microbalance. Novel insight was revealed on the mechanisms influencing nucleation and growth, by determining associated kinetic barriers as a function of precursor-Ca/U. Remarkably, as the bulk precipitate Ca/U increased from ~⅛ to unity, there was a transition from crystalline Becquerelite to primary or secondary amorphous phases, with uranate-like coordination environments. Formation of the latter was driven by solution alkalinity, and comprises a poorly-ordered matrix with occlusions of Ca2+-rich nano-clusters. A congruency limit lies Ca/U of ~1.5 Ca/U, whereupon discrete Portlandite crystallises. Solid-state transformation of all Ca2+-U(VI)-phases studied involved dehydration, dehydroxylation-decarbonation, and desorption processes. Associated kinetic barriers were catalysed by higher Ca2+-contents, and was reflected by reaction enthalpies for dehydration and desorption. Crystalline Becquerelite (~⅛ Ca/U) underwent amorphisation-crystallisation via partial egress of interlayer calcium, followed by reduction of β-UO3 to form a novel intercalation compound Ca0.18.α-U3O8. The endmember uranates Ca3U11O36, CaU2O7, Ca2U3O11, and CaUO4 crystallised from amorphous precursors with higher bulk Ca/U (~⅓, ~½, ~⅔, ~1), where Ca3U11O36 is a novel compound that is isostructural to (Pb/Sr)3U11O36. Nucleation and growth became predominant in the presence of Ca2+-rich occlusions. A higher Ca2+-loading facilitated the progressive ingress of interlayer-Ca2+, inducing a concerted axial compression in uranyl(VI) oxo-polyhedra towards the uranate-like coordination environment

Multiscale, multiphysics modeling of subsurface engineering applications

Fluid flow, particle transport, and chemical reactions in porous media play a vital role in various disciplines, including hydrology, medicine, and engineering. In particular, in the petroleum industry, subsurface engineering applications involving injection or production of fluids are associated with physical and chemical processes at the pore-scale (nano/microscale). These processes encompass fluid-rock interactions that can determine and alter the fluid behavior and rock properties at reservoir scales (macroscale). Developing engineering tools to probe and link pore-scale processes to reservoir-scale remains a fundamental research challenge to enhance our understanding and our ability to predict the observed phenomena in the subsurface In this work, I explored various subsurface engineering applications of multiphysics, multiscale modeling paradigms including pore-scale network models, experimental data, and reservoir scale simulation to investigate the role of physical and chemical interactions on the evolution of rock properties and fluid behavior. Three such applications were studied: (1) formation damage due to particle plugging during hydraulic fracturing as a result of proppant crushing and fluid invasion, (2) the evolution of migration pathways due to chemical diagenesis in unconventional reservoirs, and (3) plume characterization, storage mechanisms, and well-based monitoring during CO2 sequestration in saline aquifers. First, I employed a particle plugging simulator that integrates pore-scale phenomena with hydraulic fracturing simulation at the reservoir-scale to examine the effects of fracturing fluid invasion and proppant crushing on the formation permeability damage at the matrix-fracture interface. The model is based on the generation of 3D pore networks that capture the pore space topology and serve as the frame for fluid flow and particle transport simulations. The pore networks are coupled with a commercial reservoir-scale fracture simulator that provides the fracturing process macroscale characteristics to compute the particles' retention and their effect on the formation permeability. This integrated model aims to enhance the design and modeling of hydraulic-fracturing operations in unconventional shale reservoirs by considering the pore-scale dynamics at the matrix-fracture interface. Next, I incorporated a modeling workflow that integrates mineralogical, petrophysical, and chemical data to delve into the influence of chemical diagenesis on macroscopic properties from a pore-scale perspective. The pore-scale model proposed has two main components. The first component involves examining the depositional environment, mineralogy, and pore structure characteristics to identify diagenetic controls on the reservoir quality. The second component comprises the generation of hybrid pore network models representing the pore space, followed by the numerical simulation of fluid transport and mineral reactions related to relevant diagenetic events. The model aims to improve our understanding of the influence of diagenetic events on the migration pathways' evolution. Finally, I investigated the geological sequestration of CO2 in saline aquifers to characterize and monitor the temporal and spatial evolution of the CO2 plume. The integrated modeling framework used provides the means to ascertain the relative influence of multiple parameters on the plume characteristics and the contributing trapping mechanisms. The selected parameters involve facies distribution, aquifer-water composition, heterogeneity and anisotropy of petrophysical properties, transport physics, and operational variables like injection rate and bottomhole pressure. Several well-based fluid variables are monitored to assess the plume evolution and identify behavior correlations between the near-wellbore and plume region properties

ECOS 2012

The 8-volume set contains the Proceedings of the 25th ECOS 2012 International Conference, Perugia, Italy, June 26th to June 29th, 2012. ECOS is an acronym for Efficiency, Cost, Optimization and Simulation (of energy conversion systems and processes), summarizing the topics covered in ECOS: Thermodynamics, Heat and Mass Transfer, Exergy and Second Law Analysis, Process Integration and Heat Exchanger Networks, Fluid Dynamics and Power Plant Components, Fuel Cells, Simulation of Energy Conversion Systems, Renewable Energies, Thermo-Economic Analysis and Optimisation, Combustion, Chemical Reactors, Carbon Capture and Sequestration, Building/Urban/Complex Energy Systems, Water Desalination and Use of Water Resources, Energy Systems- Environmental and Sustainability Issues, System Operation/ Control/Diagnosis and Prognosis, Industrial Ecology

Acoustic and Elastic Waves: Recent Trends in Science and Engineering

The present Special Issue intends to explore new directions in the field of acoustics and ultrasonics. The interest includes, but is not limited to, the use of acoustic technology for condition monitoring of materials and structures. Topics of interest (among others): • Acoustic emission in materials and structures (without material limitation) • Innovative cases of ultrasonic inspection • Wave dispersion and waveguides • Monitoring of innovative materials • Seismic waves • Vibrations, damping and noise control • Combination of mechanical wave techniques with other types for structural health monitoring purposes. Experimental and numerical studies are welcome