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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 direct thermochemical liquefaction of oil palm empty fruit bunch (EFB) was performed using sub- and supercritical solvents. The total feedstock conversion at 400 °C in tetralin reached 91.8%, and 97.1% with the addition of Fe 3 O 4 and H 2 . Increasing the reaction temperature to 450 °C with n -dodecane present led to a slight increase in the total feedstock conversion. At 400 and 450 °C in n -dodecane, the liquefaction reaction afforded almost identical feedstock conversions (>77%) and high liquid product yields; however, the reaction pressure exceeded 10 MPa. The variations of the reaction performance in the n -dodecane/tetralin mixture were correlated to the quantity of tetralin. Tetralin was an ideal solvent that promoted an efficient EFB liquefaction process and suppressed char formation. The solid residues collected after the liquefaction reaction were thermally activated, and some of them showed good CO 2 adsorption capacity when compared to activated carbons.

Heavy oil was co-processed with wood biomass by using supercritical m-xylene and n-dodecane. The effects of the solvent, temperature, hydrogen, and catalyst on vacuum residue (VR) upgrading were evaluated using residue conversion, coke formation, and product distribution as performance parameters. VR was subjected to co-processing with microcrystalline cellulose (cellulose) or oil palm empty fruit bunch fiber (EFB), and the parameters were compared with those obtained from VR upgrading. Co-processing of VR/cellulose using a catalyst and hydrogen led to higher conversion (72.6 wt%) than co-processing of VR/EFB at 400 °C and the highest yield of light product (65.7 wt%). Using the Fe3O4 catalyst with H2 for co-processing positively influenced generation of the light product fraction. VR upgrading and co-processing using supercritical solvents could eliminate a certain amount of sulfur compounds from heavy oil. Co-processing of wood biomass with petroleum feedstocks in existing oil refineries can reduce the capital costs of bulk treatment.

The treatment of ballast water is indispensable for preventing ecological and economic damage from the spread of invasive species. In this study, a continuous gas bubble reactor (CBR) system was developed for the efficient disinfection of microorganisms in ballast water. Ballast water treatment (BWT) in the CBR was experimentally performed to disinfect Artemia salina in seawater by using 1) pure CO2 and 2) mixtures with CO2, N2, and/or SO2 as a simulated flue gas (CO2/N2: 20%/80% and CO2/N2/SO2: 19.2%/77.0%/3.8%). The BWT efficiency was improved with an increase in gas flowrate, residence time, gas pressure, and CO2 concentration in the gas. The toxicity of SO2 in the CO2 mixture significantly improved the mortality of microorganisms. Since good dispersion of bubbles and effective contact between bubbles and liquid were important factors in the BWT, a 100% mortality rate of microorganisms could be achieved by controlling the operating conditions in the vertical-type CBR with a counter-current flow between the gas bubbles and seawater. The CO2 gas distribution, CO2 solubility, and gas bubble size distribution in the CBR were determined using computational fluid dynamics (CFD) and experimentally confirmed using a high-speed camera. Since excess gas can be recovered from a gas-liquid separator before a ballast tank, the CBR system can be operated without using any toxic or explosive gases in an eco-friendly and energy saving manner.

Co-processing of petroleum vacuum residue (VR) and oil palm empty fruit bunch (EFB) fiber was carried out through the use of supercritical solvents. The effects of solvent (tetralin and decalin), temperature (400 and 450 °C), a catalyst, and hydrogen on the co-processing were evaluated according to residue conversion and product distribution analysis. The results were compared with only the VR upgrading results as well as the co-processing of VR and microcrystalline cellulose. Supercritical tetralin exhibited high reaction performance in both VR upgrading and co-processing of VR/EFB without significant coke formation, compared with the results in decalin. In the presence of H2, the Fe3O4 catalyst contributed toward suppressing coke formation. The co-processing of VR/EFB using tetralin could achieve a residue conversion of 86.4 wt% with only 0.8 wt% of coke formation, showing more favorable conversion than that of VR/microcrystalline cellulose. Therefore, it led to a positive effect which improved the residue conversions and yielded a great quantity of light product.

Direct thermochemical liquefaction of microcrystalline cellulose was investigated in sub- and supercritical solvents in a batch reactor. The liquefaction efficiency of hydrogen donor solvents (tetralin and decalin) was compared to that of m-xylene. Tetralin was the most effective solvent with respect to the conversion at every tested condition starting from 350 °C. At 400 °C, the total conversion of cellulose in tetralin approached 96.8–98.3% with a negligible amount of char formation. The pressure of hydrogen had little effect on conversion for any solvent, while the addition of iron oxide catalyst (Fe3O4) led to improved conversion and liquid yield from the reaction compared to reactions without the catalyst at temperatures higher than 350 °C. Hydrogen pressure in the presence of iron oxide catalyst significantly suppressed the char formation and improved liquid production. The thermal-treated chars collected after liquefaction reactions showed a fair adsorption capacity of CO2 compared to activated carbon.

The upgrading of petroleum vacuum residue was conducted with activated carbon (AC) based catalysts in sub- and supercritical m-xylene and n-dodecane. The conversion, liquid yield, coke formation, sulfur removal, and the product distribution were evaluated at various reaction conditions; different kinds of AC catalysts, temperatures (350–400 °C), H2 pressures (0.50–3.45 MPa), reaction times (5–30 min), and polar components (H2O, methanol, and ethanol in solution). The acid-treated bituminous coal derived AC produced the highest liquid yield of 76.0 wt % in supercritical m-xylene and 84.4 wt % in supercritical n-dodecane, while it also obtained the lowest coke formation of 16.3 wt % in supercritical m-xylene and 8.4 wt % in supercritical n-dodecane. When compared to the coconut shell derived AC catalyst, its acid-treated catalyst resulted in higher conversion but lower liquid yield due to the high degree of coke formation. Furthermore, the influence of reaction temperature on the upgrading reaction was more...