The Effect of Copper Addition on the Activity and Stability of Iron-Based CO2 Hydrogenation Catalysts.

Iron-based CO2 catalysts have shown promise as a viable route to the production of olefins from CO2 and H2 gas. However, these catalysts can suffer from low conversion and high methane selectivity, as well as being particularly vulnerable to water produced during the reaction. In an effort to improve both the activity and durability of iron-based catalysts on an alumina support, copper (10-30%) has been added to the catalyst matrix. In this paper, the effects of copper addition on the catalyst activity and morphology are examined. The addition of 10% copper significantly increases the CO2 conversion, and decreases methane and carbon monoxide selectivity, without significantly altering the crystallinity and structure of the catalyst itself. The FeCu/K catalysts form an inverse spinel crystal phase that is independent of copper content and a metallic phase that increases in abundance with copper loading (>10% Cu). At higher loadings, copper separates from the iron oxide phase and produces metallic copper as shown by SEM-EDS. An addition of copper appears to increase the rate of the Fischer-Tropsch reaction step, as shown by modeling of the chemical kinetics and the inter- and intra-particle transport of mass and energy.

Effects of pressure on the recovery of CO2 by phase transition from a seawater system by means of multilayer gas permeable membranes.

Using seawater doped with sodium bicarbonate and Celgard 2400 gas permeable membranes, bicarbonate ion disproportionates to carbon dioxide and carbonate when gaseous carbon dioxide is first removed from the seawater solution by diffusion through gas permeable membranes at elevated water pressures. The permeability of CO(2) by phase transition from bicarbonate solutions at pressures above 100 psi is only possible due to the use of multiple gas permeable membrane layers. The multiple layers minimize water permeability at pressures below and above the Young-Laplace bubble point of single membrane layers, however the gas permeability efficiency and rate are greatly decreased.

Mitigation of TNT and Destex explosion effects using water mist.

The effects water mist has on the overpressures produced by the detonation of 50 lb equivalent of high explosives (HE) TNT and Destex in a chamber is reported. The overpressures for each charge density were measured with and without mist preemptively sprayed into the space. A droplet analyzer was placed in the chamber prior to the detonation experiments to characterize the water mist used to mitigate the explosion overpressures. The impulse, initial blast wave, and quasi-static overpressure measured in the blast mitigation experiments were reduced by as much as 40%, 36%, 35% for TNT and 43%, 25%, 33% for Destex when water mist was sprayed 60s prior to detonation at a concentration of 70 g/m(3) and droplet Sauter Mean Diameter (SMD) 54 microm. These results suggest that current water mist technology is a potentially promising concept for the mitigation of overpressure effects produced from the detonation of high explosives.