Formaldehyde is a very important chemical with a wide range of applications. Methanol partial oxidation on Fe-MoO3 catalyst is the most favorable method for formaldehyde production. The catalyst for this process is highly selective toward formaldehyde production (selectivity > 90%). Methanol conversion in the process is also high (conversion > 98%). The scholarly work on methanol partial...
We start from the description of unsaturated flow in porous media with the
Richards' equations. This model uses pressure and saturation as unknown variables, they satisfy one parabolic equation and one algebraic relation. The Richards' equations provide a useful model in many situations, but they fail dramatically in the explanation of one specific experiment: When a highly saturated medium...
Flows in packed beds are encountered in many engineering applications, such as solar thermal energy storages, chemical catalytic reactors, petroleum and civil engineering, magnetic refrigerators, biological tissues, and pebble-bed nuclear reactors.
Critical challenge of designing packed beds involves understanding the total pressure loss, complex flow fields, heat and mass transfer...
Gravity-driven fingering is commonly observed during water infiltration in soil. An important feature of gravity fingering is the presence of saturation overshoot, which is understood to be a necessary prerequisite for gravity fingering in unsaturated flows. The Richards model in its basic form, along with the standard (monotonic) pressure-saturation relation, is incompatible with saturation...
The flow behavior through porous media is yet to be fully understood. The comprehension of the fundamental physical mechanisms and of the dynamics can significantly help the development of many applications in the engineering field.
A porous system can be formed by natural as well as by artificial processes, and is mostly described by granular media, compacted under external forces. The pore...
Nowadays, ceramic materials are used in many industries. Ceramic materials are well known by their high strength and excellent thermal and chemical stability. In addition, most of ceramics retain acceptable mechanical properties at temperatures higher than 1000 C. However, the low impact toughness of these materials limits their use in industries such as aerospace. The porous nature of the...
Many subsurface operations – such as drilling, cementing, well completion, and production – can result in damage to the rock formation near the wellbore, decreasing the permeability and resulting in a reduction in oil or gas production. Acidizing is one type of treatment that is employed to increase the permeability around the wellbore. In carbonate rocks, acidizing can not only reduce the...
