Search

Tetralin/activated carbon was applied to the upgrading of vacuum residue (VR) in a continuous reactor. The experimental performance was evaluated at a fixed pressure of 5.0 MPa in the range of 385–470 °C, and 1.5 and 3.0 h−1 of liquid hourly space velocity. A lower space velocity, which is closely related to the reaction time, led to significantly higher conversion at the cost of forming a carbonaceous product (coke). Increasing the reaction temperature greatly affected the conversion of residue into lighter products. The application of a tetralin/activated carbon to the VR upgrading resulted in high residue conversion (74.5 wt%) and asphaltene reduction (80.8%) at 470 °C, with a small amount of coke (1.2 wt%). Additionally, the tetralin/activated carbon system led to reduction of the sulfur, nitrogen and metal concentrations in the liquid products. The hydrogen-donor solvent/carbon system acts as an attractive hydrogen-donor medium in the extra-heavy oil upgrading.

To support effective geological CO2 sequestration design and operation, dissolution and reaction in CO2-brine-clay mineral particle systems (sepiolite and montmorillonite) were studied under subcritical to supercritical CO2 conditions (10 bar to 150 bar at 45 °C and 65 °C). The order of ion dissolution from the framework of sepiolite in the brine was slightly different under each experimental condition, whereas the order of dissolved ion concentration from the montmorillonite was not varied. The solubility of CO2 was lower in the CO2-brine-clay mineral particle system than in a CO2-brine system. Precipitation of amorphous silica as a secondary mineral formation was observed after the reaction of both sepiolite and montmorillonite. The CO2 solubility model, considering ion concentration and aqueous silica, reasonably predicted the CO2 solubility from subcritical to supercritical conditions. The kinetic rate constant of the dissolution reaction of sepiolite was correlated with the initial pH of the brine. After reaction with high-pressure CO2-saturated brine, the micro-crystallinity of sepiolite did not change, whereas the basal (0 0 1) plane of montmorillonite showed deformation in micro-crystallinity after the dissolution reaction. By contrast, reaction with the CO2-saturated brine led to a decrease in the surface area of sepiolite and an increase in the surface area of montmorillonite.

The fungus Cylindrocarpon destructans is the cause of root rot in many ginseng production areas in Korea. A total of 57 isolates of C. destructans were recovered from diseased roots in a survey of ginseng–growing fields from 2011-2012. Among these isolates, 37% were classified as highly virulent (causing lesions on unwounded mature roots) and 61% were weakly virulent(causing lesions only on previously wounded roots). Radial growth of highly and weakly virulent isolates on potato dextrose agar was highest at 20°C and there was no growth at 35°C. Mycelial mass production was significantly (P = 0.05) lower at pH 7.0 compared with pH 5.0. To study the effects of pH (5.0 and 7.0) and wounding on disease development, ginseng roots were grown hydroponically in nutrient solution. Lesions were significantly larger (P < 0.01) at pH 5.0 compared with pH 7.0 and wounding enhanced disease by a highly virulent isolate at both pHs. In artificially infested soil, 2-yearold ginseng roots were most susceptible to Cylindrocarpon root rot among all root ages tested (1 to 4 years) when evaluated using a combined scale of disease incidence and severity. Root rot severity was significantly (P