This paper presents an experimental study on the ability of organic-rich-shale core samples to store carbon dioxide (CO 2). An apparatus has been built for precise measurements of gas pressure and volumes at constant temperature. A new analytical methodology is developed allowing interpretation of the pressure/volume data in terms of measurements of total porosity and Langmuir parameters of core plugs. The method considers pore-volume compressibility and sorption effects and allows small gas-leakage adjustments at high pressures. Total gas-storage capacity for pure CO 2 is measured at supercritical conditions as a function of pore pressure under constant reservoir-confining pressure. It is shown that, although widely known as an impermeable sedimentary rock with low porosity, organic shale has the ability to store significant amount of gas permanently because of trapping of the gas in an adsorbed state within its finely dispersed organic matter (i.e., kerogen). The latter is a nanoporous material with mainly micropores (< 2 nm) and mesopores (2-50 nm). Storage in organic-rich shale has added advantages because the organic matter acts as a molecular sieve, allowing CO 2-with linear molecular geometry-to reside in small pores that the other naturally occurring gases cannot access. In addition, the molecular-interaction energy between the organics and CO 2 molecules is different, which leads to enhanced adsorption of CO 2. Hence, affinity of shale to CO 2 is partly because of steric and thermodynamic effects similar to those of coals that are being considered for enhanced coalbed-methane recovery. Mass-transport paths and the mechanisms of gas uptake are unlike those of coals, however. Once at the fracture/matrix interface, the injected gas faces a geomechanically strong porous medium with a dual (organic/inorganic) pore system and, therefore, has choices of path for its flow and transport into the matrix: the gas molecules (1) dissolve into the organic material and diffuse through a nanopore network and (2) enter the inorganic material and flow through a network of irregularly shaped voids. Although gas could reach the organic pores deep in the shale formation following both paths, the application of the continua approximation requires that the gas-flow system be near or beyond the percolation threshold for a consistent theoretical framework. Here, using gas permeation experiments and history matching pressure-pulse decay, we show that a large portion of the injected gas reaches the organic pores through the inorganic matrix. This is consistent with scanning-electron-microscope (SEM) images that do not show connectivity of the organic material on scales larger than tens of microns. It indicates an in-series coupling of the dual continua in shale. The inorganic matrix permeability, therefore, is predicted to be less, typically on the order of 10 nd. More importantly, although transport in the inorganic matrix is viscous (Darcy) flow, transport in the organic pores is not due to flow but mainly to molecular transport...

This paper presents an experimental study on the ability of Barnett shale core samples to store carbon dioxide. An apparatus has been built for psrecise measurements of gas pressure and volumes at constant temperature. A new analytical methodology is developed allowing interpretation of the pressure-volume data in terms of measurements in total porosity and Langmuir parameters of core plugs. The method considers pore volume compressibility and sorption effects and allows small gas leakage adjustments at high pressures. Total gas storage capacity for pure carbon dioxide is measured at supercritical conditions as a function of pore pressure under constant reservoir confining pressure. It is shown that, although widely-known as an impermeable sedimentary rock with low porosity, organic shale has the ability to store significant amounts of gas permanently due to trapping of the gas in adsorbed state within its finely-dispersed organic matter, i.e., kerogen. The latter is a nanoporous material with micropores (&lt; 2 nm) and mesopores (2-50 nm). Storage in organic shale has the added advantages because the organic matter acts as molecular sieve allowing carbon dioxide —with linear molecular geometry— to reside in small pores that the other naturally-occurring gases cannot access. In addition, the molecular interaction energy between the organics and carbon dioxide molecules is different which leads to its enhanced adsorption. Hence, affinity of shale to carbon dioxide is due to partly steric and thermodynamic effects similar to those of coals that are being considered for enhanced coalbed methane recovery. Mass transport paths and the mechanisms of gas uptake are unlike coals, however. Once at the fracture-matrix interface, the injected gas faces a geomechanically strong porous medium with dual (organic/inorganic) pore system, therefore, has choices of path for its flow and transport into the matrix: the gas molecules (i) dissolve into the organic material and diffuse through a nanopore-network, and (ii) enter the inorganic material and flow through a network of irregularly shaped voids. Although the gas could reach the organic pores deep in the shale formation following both paths, the application of the continua approximation to the percolation threshold is not known. Here, using gas permeation experiments and history-matching pressure pulse decay, we show that a large portion of the injected gas reaches the organic pores through the inorganic matrix. This is consistent with SEM images that do not show connectivity of the organic material on scales larger than tens of microns. It indicates an in-series coupling of the dual continua in shale. The inorganic matrix permeability is therefore predicted less, typically in the order of 10 nD. More importantly, transport in the organic pores is not due to flow but mainly pore and surface diffusion mechanisms.

The development of high-quality polycrystalline silicon film is of interest for active-matrix organic light-emitting displays. Here, NiCl 2 vapor was applied for the first time to enhance the crystallization of amorphous silicon film. The crystallization of amorphous Si showed that round-shaped Si grains grow and become impinged to form polyhedral-shaped grains with diameters of 10 to 25 μm. It was found that the growth of large grains was possible via the merging of fine needle grains with the same directional growth. The crystallized film showed a high degree of crystallinity and a very smooth surface with a roughness of 0.53 nm. The field-effect hole mobility and subthreshold swing of the p-channel thin-film transistor fabricated using the poly-Si film were 113 cm 2 /V • s and 0.4 V/decade, respectively. The high performance of the thin-film transistor is attributed to the large grain size, the high crystallinity, the low Ni contamination and the smooth surface of the poly-Si film crystallized in NiCl 2 vapor.

Development of high quality polycrystalline silicon film is in strong demand for active matrix organic light emitting displays. In this study, AlCl 3 vapor was applied to enhance the crystallization of amorphous silicon film. The crystallization of amorphous Si showed that round-shaped Si grains were nucleated from amorphous Si film and they impinged each other to form polyhedralshaped grains. The grain size in the crystallized Si film was very large and the surface roughness was very small. The field-effect hole mobility and subthreshold swing of the p-channel thin film transistor were 94 cm 2 /V s and 0.4 V/decade, respectively. The high performance of this thin film transistor is attributed to the large grain size, high crystallinity, and smooth surface of the poly-Si film crystallized in AlCl 3 vapor.

Membrane distillation is a promising option for desalination owing to its advantages, but additional studies are still required before drawbacks such as membrane wetting can be resolved. To investigate the...