CO2 corrosion phenomena are characterized by a high corro sion rate even under weak acid conditions and cause specific corrosion figures such as ringworm, wormhole and mesa corrosion. The former is due to the catholic reaction and the latter are due to the properties of the corrosion product. In addition to analyses of previous research, CO2 corrosion of pure iron was investigated. The activation energy of CO2 corrosion of pure iron at PCO2=3MPa was very similar to that of the hydration reaction of CO2. Although the cathodic reaction is a superposition of the diffusion controlled reduction of H+ ion and direct reduction of H2CO3, the latter was the main reaction at high PCO2, 1.1-3MPa and/or at high temperature 313-353K. CO2 corrosion can be categorized into three types depending upon the temperature, and is closely related to the properties of the corrosion product film caused by formation of FeCO3. The effect of the environmental conditions and metallurgical fact ors on CO2 corrosion behavior, specifically both structure and constituents of corrosion products, were investigated. The applicability of the de Waard-Milliams equation, which is utilized for engineering purposes to predict the corrosion rate of carbon steel, was investigated experimentally and theoretically. Anti-CO2 corrosion tubular materials and their properties are discussed.
Special asphalt mixtures are now used as much as continuously graded mixture. The method for mixture design described in the MANUAL FOR ASPHALT PAVEMENT and GUIDE FOR DRAINAGE PAVEMENT may not apply to all types of asphalt mixtures. In addition, the properties of asphalt mixtures are influenced by the quantity of asphalt mortar and filler bitumen. Therefore, consideration of these factors is desirable for improved mixture design. In this study, the ratio of asphalt mortar volume to coarse aggregate void volume and the ratio of filler bitumen volume to fine aggregate void volume were defined as design factors, to examine wheher these design factors can be used to predict the properties of the asphalt mixtures. The results clearly showed that the properties of dense-graded, dense gap-graded and open-graded asphalt mixtures could be predicted effectively by these factors. Custom, effective mixture design of asphalt mixtures can be achieved based on these factors.
Hydrothermal cracking of a Canadian Athabasca oil sand bitumen was conducted in a batch autoclave at 673 to 713K under 1.0 to 5.0MPa hydrogen to determine the most favorite reaction conditions. Various catalysts were prepared using MgO, activated carbon, SiO2 and Al2O3 as the support, and Ni as active metal, to investigate the catalytic activity for the hydrothermal cracking of the oil sand bitumen. The basic MgO and neutral activated carbon supported catalysts showed lower coke yields than the acidic SiO2 supported catalyst. Coke and gas yields were reduced when the Ni/SiO2 catalyst was doped by 1wt% potassium salt.
A new phenomenon of decalcification of the cement concrete structure and dissolution of bitumen in bituminous pavement is described, caused by the surfactants included in the windshield washer fluid of automobiles. Decalcification occurs in cement concrete samples in the laboratory even at low concentrations of surfactant of 25ppm. Recently, foam with fine bubbles have been observed in the water on pavement just after rain worldwide. The decalcification reaction was identified as an ion exchange reaction between the calcium ions Ca2+ in the concrete and Na+ in the surfactants using the electron spectroscopy for chemical analysis (ESCA) method. Bitumen was also found in the decalcified cement concrete, from which the Ca component had dissolved out gradually with time.
Recent conditions in the supply of feedstock have enforced the development of a flexible multifunctional and high performance catalyst which can process either naphthalene or o-xylene to produce phthalic anhydride. No other detailed study has been reported on the preparation of a fluidized-bed TiO2-supported V2O5 catalyst for this purpose. In this study, a new spray-drying method was successfully developed to prepare the catalyst using titanium hydroxide gel to form the anatase TiO2 (2θ=25.3°) with a crystallite diameter of less than 10nm after drying at 300°C. The most effective third component of this support was investigated to prepare micro-spherical catalyst with uniform composition and good attrition resistance for optimum performance. Increased selectivity for phthalic anhydride production was achieved with the weight ratio of K2SO4/V2O5<1, which markedly differed from that of previously reported SiO2-supported V2O5 catalyst. Addition of La2O3 stabilized the anatase phase of TiO2 and enhanced the activity and selectivity, whereas addition of B2O3 considerably increased the attrition resistance of the fluid catalyst. TiO2-supported V2O5 catalyst with added La2O3 and B2O3 was highly effective for the fluidized-bed oxidation of both naphthalene and o-xylene feed. Evaluation tests using the developed TiO2-supported V2O5 catalyst, at a commercial plant under naphthalene feed stock operation, demonstrated the high catalytic performance and stable operation for the production of phthalic anhydride even at ca. 2/3 feeding operation compared to the SiO2-supported V2O5 catalyst.
The transalkylation of trimethylbenzene with benzene was investigated over Ferrierite, ZSM-5, Mordenite, β-type and Y-type zeolite catalysts, and the transalkylation activities were compared. Liquid phase transalkylation was performed with a batch reactor under the conditions of 250°C, 3.0MPa, and molar benzene/trimethylbenzene ratio of 1. The transalkylation proceeded over Mordenite, β-type and Y-type zeolites, and Y-type zeolite exhibited the highest catalytic activity of the three catalysts. USY-type zeolite, a dealuminated Y-type zeolite, had a higher activity than Y-type zeolite. This result may be due to the formation of mesopores through dealumination. The effect of the acidity of the zeolites on the transalkylation was investigated using ion (Mg2+, Ca2+, Sr2+, Ba2+)-exchanged Y-type zeolite. The catalytic activity for the transalkylation decreased with lower acidity of the zeolite.
Sericite, molybdenum disulfide (MoS2), melamin cyanuric acid adduct (MCA), and their mixtures were investigated as lubricants for the screw applied at high temperature, when appropriate solid lubricant was added to the mineral oil and/or to the lithium soap grease. In the process of tightening and loosening of the bolt-nut at room temperature, MoS2 and MCA produced low torque coefficient, but their values fairly increased after the 5h heat treatment at 800°C. Sericite and its mixture with MoS2 resulted in lowering or almost at constant loosening torque before and after the heat treatment. In the high speed four-ball tests, better results were realized from the sericite-added grease than from the graphite-added grease. Sericite showed almost the same extreme pressure property as MoS2 did when used together with EP agent containing sulfur and phosphorus.
Many simulation studies were conducted about the importance of perforated well length on horizontal well performance. All of these studies suffered from their dependence upon theoretical models, which lack plausibility due to the lack of accurate experimental and/or field data. Therefore, there is a great need for experimental data to be used for tuning the single well simulation models before applying a full field simulation of oil reservoirs with horizontal wells. This experimental study was designed to investigate the influences of fraction of perforated length, total length, and fractures, which do not intersect with well axis, on the productivity of horizontal wells. An experimental model (60cm×40cm×20cm) was designed and used to achieve the study objectives. Carefully sized sand-packs were used to represent the homogeneous unconsolidated porous media while a perforated aluminum sheet was used as a horizontal fracture parallel (horizontal fracture) and perpendicular but not intersecting (vertical fracture) the horizontal well axis in sandpack. Eighteen runs for homogeneous porous media with and without fracture systems were carried-out using horizontal wells with different lengths and different perforation fractions of total length. The results indicated that the increase of perforated well length increases flow rate of the horizontal well for both homogeneous and fractured formations that do not intersect with well axis. Furthermore, horizontally-fractured formation parallel to and vertically-fractured formation vertical to well axis improve productivity of horizontal well for different perforation ratios. A single vertically-fractured porous medium provides higher productivity ratio than horizontally-fractured one for the same perforation length and intensity, when both fracture systems do not intersect with well axis. Several empirical equations were developed to correlate the horizontal well productivity with perforated length for homogeneous and fractured porous media.
Dibenzothiophen (DBT) contents were analyzed quantitatively and qualitatively in straight-run gas oil (LGO, S: 12, 000ppm), deep-hydrodesulfurized gas oil (DGO, S: 147ppm), ultra-deep-hydrodesulfurized gas oil (HDGO, S: 18.5ppm) and catalytically-cracked gas oil (light cycle oil: LCO, S: 2600ppm). The total amount of DBTs in LGO was 4000ppm and gaschromatography of LGO using a sulfur chemiluminescence detector showed ca. 100 peaks of DBTs. The major DBTs in DGO were 4, 6-dimethylDBT, 4-ethyl-6-methylDBT, 1, 4, 6-, 2, 4, 6- and 3, 4, 6-trimethylDBTs, 4, 6-diethylDBT, 1-ethyl-, 2-ethyl- and 3-ethyl-4, 6-dimethylDBTs, and tetramethylDBTs with methyl groups at the 4- and 6-positions. The types and the relative amounts of the DBTs of HDGO were very similar to those of DGO. The total amount of DBTs in LCO was 2000ppm and the composition of DBTs was similar to that of LGO.
The additive effect of noble metals (Rh, Ir, Ru, and Pd) on the catalytic activity of Ag/Al2O3 for the selective reduction of NO with n-decane in the presence of O2, H2O and SO2 was investigated. Although NO reduction activity of Ag/Al2O3 was decreased by coexisting SO2 at temperatures below 450°C, the addition of Rh improved the activity at 300-400°C. Optimum Rh loading was 0.05-0.1wt% and the effect was remarkably observed at low concentration of coexisting SO2.