Detailed geological models can now be developed by interpreting different data in a consistent and integrated manner with the advances in computer technology and stochastic methods. Reservoir simulation is important for reducing uncertainties in geological models by history matching with dynamic data. Streamline-based simulation has advantages over conventional finite-difference models in computation speed, accuracy, and visualization. Faster computation is attributed to less frequent solutions of the pressure equation, one-dimensional solutions along streamlines replacing three-dimensional flow calculations, and operator splitting. Streamline-based simulation is particularly suited to repeated history matching for multiple equi-probable geological models. Applications are demonstrated with model development for upscaling, tracer flow simulation, automatic history matching, and dual-porosity modeling.
The Moriyoshi Breaking Point (MBP) test, Fraass Breaking Point (FBP) test and conventional tests, i.e., performance-related grade tests developed by the Strategic Highway Research Program (SHRP), were performed on asphalt of various ages at low temperatures, and the Thermal Stress Restrained Specimen Test (TSRST) on asphalt mixtures. In addition, a field investigation on relationships between the MBP of asphalt residuals aged by the High Temperature Long Time Durability test (HTLTD) and pavement-cracking temperatures was conducted. A strong correlation was found between the results of the MBP, FBP and conventional tests performed on asphalt concrete. The rate of strain and brittle point of the asphalts were linear during the various tests, and the MBP temperature after HTLTD testing could be used to prevent low-temperature cracking.
The present study investigated the effects of trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CyDTA) addition on the 1-octene hydrogenation activity and surface structure of CoMo/Al2O3 catalyst as a method to control the olefin hydrogenation activity. Irrespective of Co/Mo molar ratio, 1-octene hydrogenation activity at 453 K and 1.3 MPa decreased in the following order: Mo/Al2O3 > CoMo/Al2O3 > CyDTA-CoMo/Al2O3 Co/Al2O3. Modification with CyDTA had little effect on the hydrogenation activity of Mo/Al2O3. Thus, modification with CyDTA facilitates the inhibiting effect of Co addition on the hydrogenation of 1-octene. Our previous study found that modification with CyDTA greatly improves the hydrodesulfurization (HDS) activity of CoMo/Al2O3. Therefore, we expect that modification with CyDTA will greatly improves the HDS selectivity of CoMo/Al2O3 in the presence of olefins. Furthermore, the present characterization of CoMo/Al2O3 modified with CyDTA by NO adsorption techniques suggested that modification of CoMo/Al2O3 with CyDTA facilitates the formation of the Co-Mo-S phase even at lower Co/Mo molar ratio, at which Co atoms block the edge sites of MoS2 nanoclusters, leading to the improved HDS selectivity.
Addition of polyethylene glycol (PEG) as a water soluble organic compound to the impregnation solution during catalyst preparation was investigated to improve NiO-MoO3/Al2O3 and NiO-MoO3-P2O5/Al2O3 hydrodesulfurization catalysts. XPS measurement suggested that PEG addition increases the dispersion of nickel and molybdenum on the alumina support and improves dibenzothiophene and resid hydrodesulfurization activity. The effect of PEG addition was significant for catalyst prepared from alumina with lower specific surface area and higher phosphorus content, in which the active metal precursor tends to easily aggregate. PEG might block the aggregation of active metal precursors during the drying step and may increase the number of hydrodesulfurization active sites.
A new recycling technology is proposed for separating and recovering aggregate and binder from asphalt pavement waste to develop a sustainable asphalt pavement recycling system. Investigation of the system used water as the solvent, which is the most convenient, economic and safe solvent for humans and the environment. High-temperature and high-pressure water was evaluated for removing the binder from the asphalt mixture and recovering the aggregate. The study found that high-temperature and high-pressure water could remove the binder, particularly in the supercritical region, and that water was effective for removing binder and recovering aggregate from Type II modified asphalt as well as straight asphalt. Further removal of the remaining binder was achieved by repeating the tests in the sub-critical region where adequate effects were not achieved in a single test, suggesting the potential for an iterative approach under low-temperature and low-pressure conditions that would be more suited to commercialization. The present high-temperature and high-pressure water method of separation and reclaiming technology can recover and recycle valuable natural aggregate and oil resources from asphalt pavement waste.
Lube base oils were prepared by hydrocracking/isomerization of Fischer-Tropsch synthesized waxes and long-chain α-olefins with various carbon chain lengths. Correlations between operation conditions, viscosity properties of base oil, and molecular structures were investigated. Prepared base oils showed very high viscosity indexes of up to 159, but these varied widely with the severity of the hydrocracking/isomerization conditions and feedstock. Viscosity indexes of base oil had a good correlation with the severity of the hydrocracking/isomerization conditions, that is higher conversion resulted in lower viscosity index. "Average branching numbers" were calculated from the average carbon numbers and the ratio of CH, CH3 carbons obtained from 13C-NMR analysis, considering that the base oils mainly consisted of noncyclic paraffins. Increased conversion resulted in decreased average carbon number and increased average branching number with all feedstocks. Even with conversion of under 10%, about 2 branches per molecule were generated. On the other hand, the rate of generation of 3 or more branches was comparatively low. Average carbon number and average branching number also showed good correlations with the viscosity properties of the base oil such as kinematic viscosity and viscosity index. Viscosity indexes increased with higher average carbon number or lower average branching number. The effect of average carbon number or average branching number on the viscosity index depended on the feedstock, so a new index (average carbon number)2 × (average branching number)−1 was introduced as a molecular structural parameter of paraffins, and the index was confirmed to indicate the viscosity index regardless of the feedstock. A similar structural parameter (average carbon number)a × (average branching number)b was applied to kinematic viscosity. Kinematic viscosities at 40°C and 100°C showed good correlations when (a, b) = (3.5, 0.9) and (3.0, 0.5), respectively.
Carbon black, used as a reinforcing filler for rubber materials, was evaluated for asphalt binders in pavements. Carbon black added to straight asphalt within 20 wt% caused an increase in the elastic modulus and a decrease in the viscosity of the asphalt, especially at temperatures higher than room temperature. Addition of carbon black raised the maximum service temperature of asphalt in the category of the binder performance grade according to the SHRP (Strategic Highway Research Program) specifications. On the other hand, addition of carbon black also increased the failure strain at low temperatures. Furthermore, addition of carbon black reduced the coefficient of thermal expansion (CTE) of asphalt to closer to that of aggregates. In asphalt mixtures, tensile stress occurs at the boundary between asphalt and aggregate with decreasing temperature due to the CTE difference. Addition of carbon black reduced this stress. Carbon black addition to asphalt has the potential to improve both deformation resistance in the high temperature region and crack resistance in the low temperature region, which were empirically considered to be contradictory. Therefore, carbon black is an effective filler for improving the durability of asphalt pavements.
In order to assure the safety of oil pipeline transmission, it is very important to continue routine inspection of offshore pipelines to identify defects or corrosions as early as possible. A high-speed inspection data acquisition system was developed for the magnetic flux leakage (MFL) method, with 12 bit sampling precision and 1.25 M/s sampling frequency. This system consists of a micro-computer, electronic memory, pre-processing circuit, power unit, digital signal processor (DSP), Field Programmable Gate Array (FPGA) and other components. The method adopts hardware and software cooperation to control data acquisition, filtering, encoding, handling, storage and transmission. The main function is MFL signal pre-processing, real-time data acquisition, de-noising and data compression. The basic characteristics of the system, design considerations, data filtering, data compression methods and experiment results are described. Experiments showed the system has a good performance.