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The effect of carbon dioxide (CO2) on the desulfurization of sintering flue gas with hydrate (Ca(OH)2) as an absorbent was investigated, and the formation of calcium carbonate (CaCO3) and its effect on the desulfurization was discussed. The competitive relationship between carbon dioxide (CO2) and sulfur dioxide (SO2) with the deacidification agent in sintering flue gas is discussed thermodynamically, showing that sulfates are more likely to be generated under high oxygen potential conditions and that SO2 reacts more preferentially than CO2 under a thermodynamic standard state. The amount of produced CaCO3 increases under the condition that the CO2 concentration is absolutely dominant to SO2 in the sintering flue gas atmosphere. The effect of temperature, humidity and CO2 concentration on the desulfurization of Ca(OH)2 are discussed experimentally. The increasing temperature is not conducive to desulfurization, and the humidity can promote desulfurization, while excessive humidity could inhibit desulfurization. The suitable relative humidity is 20%. In situ generated calcium carbonate has a certain desulfurization effect, but the desulfurization effect is not as good as Ca(OH)2. However, a large proportion of CaCO3 was produced in the desulfurization ash under the condition that CO2 concentration was absolutely dominant to SO2 in the sintering flue gas atmosphere. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) was applied to investigate the grain boundaries on ASTM grade-7 titanium (Ti-7) with a freshly polished surface, and the results showed that the alloying element, Pd, and the impurity, Fe, cosegregated to grain boundaries. Scanning electrochemical microscopy (SECM) was used to study the variations in reactivity on Ti-7 exposed to an aerated neutral solution of 0.1 M NaCl. Locations that possessed an enhanced reactivity compared to the oxide-covered (Ti[O.sub.2]) surface of the grains on SECM images were proposed to be the boundaries. These areas were further activated by the application of a cathodic bias, and interconnection of the active locations allowed the construction of 'grain boundary maps'. Variations in surface reactivity were quantitatively analyzed by fitting probe approach curves (PACs) to curves simulated with a model based on finite element analyses using the platform of COMSOL multiphysics software. The difference in reactivity between active grain boundaries and oxide-covered grains was up to a factor of 100 on freshly polished surfaces. This difference decreased to a factor of 10-15 after longer-term exposure of the Ti-7 to the aerated solution, indicating partial passivation of the Pd/Fe-stabilized [beta]-phase in the grain boundaries. PAC analyses of oxide-covered grains showed that the reactivity increased logarithmically as the bias potential to the Ti-7 was decreased, consistent with reduction of the insulating Ti[O.sub.2] layer to a more conductive TiOOH layer.

The flow of aqueous phases through porous media shapes the world. It changes the courses of rivers, erodes mountainsides, dissolves historical monuments, builds caves, regulates the carbon cycle, and changes porosity in aquifers and hydrocarbon reservoirs. Despite the significance of this process both to natural phenomena and human endeavors, fundamental insight into the mechanisms that drive it at the Ångstrom scale is scarce. Here, we employ environmental transmission electron microscopy (ETEM) to visualize interactions between water and various types of porous media, including sandstone, limestone, and dolostone samples, at Ångstrom resolution in real time. Unlike other techniques presented in the literature, ETEM allows for direct visualization of both the aqueous phase and the porous media. As expected, dissolution and recrystallization were observed to significantly impact the shapes, sizes, and interconnectivities of the pores in the rocks. However, for the first time, we provide direct in situ experimental evidence that adsorption‐induced strain can also significantly impact the above‐mentioned parameters, especially in micropores. In some cases, adsorption was observed to reduce effective pore size by more than 60%. The magnitude of the change in pore size was found to vary with pore wall mineralogy and pore geometry. This work presents the first direct Ångstrom‐resolution observations of liquid adsorption films and adsorption‐induced strain. Key Points: Rock‐fluid interactions are directly observed in situ at Ångstrom resolutionThe thicknesses of adsorbed water films on pore walls are measuredAdsorption‐induced strain is shown to alter pore size by more than 60% [ABSTRACT FROM AUTHOR]

Near-miscible supercritical CO 2 (scCO 2) injection and its underlying pore-scale physics were experimentally investigated in an oil-wet carbonate rock at elevated temperature and pressure conditions using X-ray microtomography. The results of in situ contact angle measurements yielded direct evidence showing that the scCO 2 injection triggered a wettability reversal process resulting in reduced oil-wetness. As the scCO 2 injection progressed, we observed a distinct wettability state where the wetting preference of the solid to the scCO 2 , oil, and brine phases was similar due to the wettability reversal. Consequently, pore sizes neither dictated any preferential invasion order nor restricted the displacement efficiency of the injection process. Furthermore, we identified a type of spreading system where spreading oil layers formed but did not exist globally across the pore space between the scCO 2 and brine phases. Gaussian curvature analysis showed that the scCO 2 and oil phases were well-connected at the early stage of the scCO 2 injection, whereas brine connectivity was relatively poor. As the injection continued, brine connectivity was improved due to the wettability reversal effect. Moreover, displacement events including double and multiple displacements were identified and discussed. They included a variety of events that had scCO 2 as the first phase and oil and brine as the subsequent phases. The diversity and affordability of such displacements were much higher than those previously observed during N 2 injection in oil-wet systems where mostly gas-to-oil-to-brine double displacements took place. The interplay of scCO 2 -oil miscibility, the distinctive wettability state, favorable fluid connectivity, and frequent double/multiple displacements resulted in an exceptional displacement efficiency during near-miscible scCO 2 injection. • A distinct wettability state for three-phase flow in porous rock is identified. • We identify a type of spreading behavior where oil layers formed but did not globally exist. • We probe the diversity and affordability of double and multiple displacements under varying wettability conditions. • Miscibility and connectivity of fluids are in situ examined at pore scale. [ABSTRACT FROM AUTHOR]

Image logs provide important information on lithology, sedimentary textures, paleoflow directions, fractures and in situ stress analysis. Lacking of criteria used for establishing the image log facies limits the applications of image logs in sedimentary reservoir interpretation. This paper provides a thoroughgoing review focusing on the recent applications of borehole image logs for sedimentological and structural description and interpretation, and aims to establish image log facies which can provide guidelines in sedimentary reservoir interpretation. This paper firstly summarizes the principles and basic characteristics of various imaging logging tools, and then briefly introduces the pre-processing workflow of the image log data. Then the generated images are used for depth and orientation shifts of cores by calibrating individual sedimentary and structural features. Descriptive and concise image log facies are established based on combinations of image textures including dip type, dip pattern, and color scheme, and the characteristics as well as physical criteria for each individual image facies are summarized. The established image log facies are then interpreted in terms of structural and sedimentological features such as lithology, sedimentary structures, vugs, fractures and faults. The image log facies and its stacking patterns are then used to interpret the lithofacies associations by calibrating with cores and conventional logs. Natural fractures and induced fractures are recognized by image logs, and the principles of breakouts and drilling-induced fractures for in-situ stress analysis are reviewed. Then the applications of image logs in investigation of fracture attitudes and states, as well as in computation of fracture parameters are summarized. The procedures to evaluate fracture effectiveness through image logs are discussed. At last, the application of image logs for structural dip analysis is reviewed, and image logs are used for recognizing faults, fracture sets, and attitudes of stratum through the dip patterns. The basic procedures for paleocurrent reconstruction, which includes dip picking of cross beddings, structural dip determination and structural dip removal, are reviewed. Then the paleocurrent directions of the Lower Cretaceous Bashijiqike Formation in the Kuqa depression were reconstructed, which could help further understanding of the depositional systems. This review will help extend the utility of image logs in interpreting small to large -scale sedimentary and structural features, and bridges the gaps between well log analysis and sedimentary and structural interpretation. [ABSTRACT FROM AUTHOR]

The effect of carbon dioxide (CO 2 ) on the desulfurization of sintering flue gas with hydrate (Ca(OH) 2 ) as an absorbent was investigated, and the formation of calcium carbonate (CaCO 3 ) and its effect on the desulfurization was discussed. The competitive relationship between carbon dioxide (CO 2 ) and sulfur dioxide (SO 2 ) with the deacidification agent in sintering flue gas is discussed thermodynamically, showing that sulfates are more likely to be generated under high oxygen potential conditions and that SO 2 reacts more preferentially than CO 2 under a thermodynamic standard state. The amount of produced CaCO 3 increases under the condition that the CO 2 concentration is absolutely dominant to SO 2 in the sintering flue gas atmosphere. The effect of temperature, humidity and CO 2 concentration on the desulfurization of Ca(OH) 2 are discussed experimentally. The increasing temperature is not conducive to desulfurization, and the humidity can promote desulfurization, while excessive humidity could inhibit desulfurization. The suitable relative humidity is 20%. In situ generated calcium carbonate has a certain desulfurization effect, but the desulfurization effect is not as good as Ca(OH) 2 . However, a large proportion of CaCO 3 was produced in the desulfurization ash under the condition that CO 2 concentration was absolutely dominant to SO 2 in the sintering flue gas atmosphere.