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In this study, the impact of soda−air−anthraquinone (AQ) pulping conditions on delignification and silica precipitation onto pulp fibers and paper sheets was studied. The results showed that the yield and silica precipitation slightly increased upon application of AQ in soda−air pulping. Scanning electron microscopy (SEM) and elemental analysis confirmed the deposition of silica-related particles on fibers and on paper sheets for both soda−air and soda−air−AQ pulping. Furthermore, increasing the cooking temperature had a stronger impact on delignification and silica deposition than did increasing the cooking time for soda−air−AQ pulping. In another set of experiments, the influence of cationic poly(vinyl alcohol) (CPVA) with two different molecular weights on improving the strength properties of straw pulps produced under various soda−air−AQ pulping conditions was studied. The adsorption of CPVA onto straw pulp and its effect on silica retention for paper sheets were comprehensively investigated.

Abstract Thermal-Solvent Assisted Gravity Drainage processes are heavy oil recovery processes in which the stimulation mechanism for bitumen viscosity reduction is by heating and dilution. The range of the injected solvent concentration with steam may be low such as in Solvent Assisted-SAGD or very high such as in Heated Vapour Extraction. The performance behaviour of these processes is significantly driven by the complex thermodynamic interaction of steam and solvent, heat transfer, multiphase fluid equilibrium and flow in the porous medium. ExxonMobil and its affiliate Imperial have been optimizing the existing recovery processes and developing new technologies to improve the efficiencies and environmental performance of the heavy oil production operations. Recent focus has been on developing thermal-solvent based recovery processes through an integrated research program that includes fundamental laboratory work, advanced numerical simulation studies, laboratory scaled physical modeling, and field piloting. The research program aims at in-depth investigation and understanding of process physics and mechanisms, and evaluating process performance and behaviour to enable development of new recovery methods and to enhance the performance. This paper focuses on the fundamental concepts of Azeotropic Heated Vapour Extraction, a new thermal solvent recovery technology developed by ExxonMobil-Imperial. This technology takes the combined advantages of the solvent dilution mechanism for enhanced oil production rate with the minimum required energy (GHG emission), as well as the effectiveness of energy transport of steam to minimize the required solvent in circulation for the extraction process. In this paper, the complex solvent-steam phase behaviour and reservoir fluid flow and their interaction under operating conditions are investigated. The analysis of experimental and modeling data shows that the injection of solvent-steam mixture at its azeotropic condition results in significant improvement in process key performance indicators (KPI's). At these conditions, the reservoir is heated to the minimum boiling temperature of the solvent-steam mixture compared to a Heated VAPEX or Solvent Assisted-SAGD process resulting in the reduction of the required energy thereby minimizing the solvent-to-oil ratio. Also, due to phase equilibrium, the vaporization of in-situ water is prevented resulting in the reduction of retained solvent in the depleted zone of the reservoir. It is found that an improvement in the process KPI's is dependent on the volatility of the selected solvent. The process KPI's also vary with operational conditions. The recovery process is optimized for certain reservoir constraints through the selection of the solvent boiling range and consequently the azeotropic steam content in the injected mixture.

Abstract Mo improved Ni/Al2O3 catalysts were prepared and characterized, which demonstrated good catalytic performance for thioetherification process of FCC gasoline. The physico-chemical properties of the Ni/Al2O3 catalysts with different amounts of Mo were characterized by physical techniques and were correlated with their catalytic performance. Experimental results showed that bimetal (Mo and Ni) based catalysts displayed superior catalytic performance than mono-metal (Ni) based catalysts. Addition of Mo to Ni catalysts could inhibit the formation of NiAl2O4 crystallites and facilitate the formation of active precursor NiMoO4, contributing to the formation of more active sites during the presulfidation process. The micro-morphology of active species was restructured and the needle-stacks of Ni-Mo-S were observed on the Mo improved catalysts. These structures and properties had important influence on the thioetherification. By optimizing the Mo/Ni atomic ratio, the catalysts with a Mo/Ni atomic ratio of 0.3 had suitable micro-morphologies and properties, exhibiting the best catalytic performance and selectivity for thioetherification.

Abstract Performance predictions made by reservoir simulators are highly dependent on experimentally-determined relative permeability data assigned to simulation grid cells. There is often no apparent relationship between this type of data and a quantifiable property of cells, meaning that samples within a group of neighboring relative permeability curves do not have similar values of a common characterization property. On the other hand, it is easier to correlate primary drainage capillary pressure data to cell properties and create a petrophysical static rock type (PSRT) from a group of similar capillary pressure data. The common approach is to average the relative permeability data corresponding to each PSRT and input that into a simulator. In practice, relative permeability curves corresponding to a given PSRT would exhibit a significant scatter, especially in carbonate formations. This will cause the resulting average relative permeability data to be highly uncertain and poorly representative of true dynamic behavior of the cells. In this study, a new technique is proposed to reduce uncertainties associated with classical methods of assigning relative permeability data to grid cells of a simulation model. The idea is based on a robust and universal criterion for characterization of dynamic characteristics of rocks from laboratory-derived flow data to define a petrophysical dynamic rock type (PDRT). A PDRT is defined as a collection of rocks with similar True Effective Mobility (TEM) behavior. A TEM-function for analysis of relative permeability is defined as a product of relative mobility by the square of a mean pore radius, and is analogous to the well-known J-function for scaling capillary pressure curves. For a given PDRT, a special weighted average of corresponding relative permeability data, or average TEM data should be used as input to a simulator. In the latter case, the simulator should have the capability to back-calculate cells’ quasi-relative permeabilities using the inputted average TEM data. Moreover, we show that factors such as wettability and pore-scale heterogeneity can cause phase-dependent dynamic characteristics (i.e., different dynamics with respect to each fluid phase). Hence, different dynamic rock typing schemes should be applied to the flow of each fluid in system. A structured methodology is presented to identify PDRTs using TEM-function and prepare input parameters to simulators by analyzing relative permeabilities using the universal criterion developed in this work. Ultimately, special core analysis data from the Asmari Formation, a carbonate reservoir from one of the Iranian Fields, is used to verify and demonstrate the applicability of the presented technique.

A study designed to refine the procedure for performing ab initio molecular dynamics calculations (AIMD) on chemical reactions is presented. Of key interest is the calculation of changes in free energy along the entire reaction path. Several simple elementary reactions are studied with the Car−Parrinello projector augmented-wave (CP−PAW) density-functional theory (DFT) methodology. The illustrative gas-phase bimolecular addition reactions are (i) a σ complexation of BH3 + H2O → H2O·BH3, (ii) the Diels−Alder reactions of butadiene with ethene, C4H6 + C2H4 → cyclohexene, 1,3-cyclopentadiene (CP) and ethene, CP + C2H4→ norbornene, and the stereoselective reaction of 5-amino-CP with ethene, amino-CP + C2H4 → amino-norbornene, (iii) the carbene cyclopropanation Cl2C + C2H4→ Cl2C3H4, and (iv) the dimerization of ketene. These reactions were used to test both the slow-growth and point-wise thermodynamic integration (STI and PTI) methods of phase-space sampling as well as the Nose−Hoover and Andersen thermostats....

This article examines both oxygen looping cycles (otherwise known as chemical looping combustion), and lime-based CO2 looping cycles, where calcined limestone is used for in situ CO2 capture. There...

Due to the demand for acid and base in brackish water reverse osmosis (RO) desalination plants located in remote areas and the difficulty of transporting acid and base, bipolar membrane electrodial...

Abstract Steric interference of two bay-hydrogen atoms causes the benzo[c]phenanthrene radical cation to be non-planar. The energy required to remove one of these H atoms (2.8 ± 0.1 eV, from iPEPICO spectroscopy) is 1.5 eV lower than that required from the planar tetracene ion due to the formation of a new C C bond. This low dissociation energy precludes benzo[c]phenanthrene ions losing C2H2 (observed from tetracene with an energy of 4.2 eV). The B3-LYP/6-311++G(2d,p) reaction pathways to C2H2 loss are presented and found to be mediated by azulene-containing intermediates. The second IE of tetracene was measured to be 19.0 ± 0.2 eV.

Medium voltage drives are increasingly used in oil field facilities for high power electrical submersible pump (ESP) wells. The load filter remains to be a critical component in such applications. In this paper, a load filter design method for medium voltage drive applications in ESP systems is proposed, which is suitable for various types of medium voltage drives and with different lengths of cables involved in ESP systems. Computer simulation is conducted for a subsea-ESP system using a neutral point clamped (NPC) inverter medium voltage drive as a case study, three scenarios (no load filter, with an improperly designed load filter, and with the load filter designed using the proposed method) are investigated. The sensitivity study is also conducted using different lengths of cabling for the subsea-ESP system with the designed load filter installed. The simulation results of the case and sensitivity studies verify the effectiveness of the designed load filter using the proposed method. The designed load filter was installed with the same NPC inverter medium voltage drive used in the case study and commissioned in a test ESP well. Field measurements of the test well after the drive and the load filter were commissioned further verify the effectiveness of the proposed load filter design method.

In the pulp and paper industry, during major modernization projects the overall energy system consequences are often not estimated in detail, usually only local energy consequences are taken into account when evaluating possible projects. In this paper, the effects on the overall energy system when installing an advanced delignification process (i.e., a "state-of-the- art" pulp digester and oxygen delignification process) will be presented. Also, the effect such an installation has on the potential for further energy integration is discussed. Furthermore, the CO2 consequences for both installing such a system and integrating the mill further energy-wise are presented.