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Abstract The prime purpose of this work is to prepare a novel kind of Pickering interfacial solid catalysts for biodiesel production to meet the requirements of highly efficiency and environmental benign. To achieve this goal, the core–shell P[xSPA-yDABCO]@SiO2@Fe3O4 composite materials with a shell of photo-responsive and base catalytic sites were manufactured by means of layer-by-layer fabrication method. The modified materials, entirely characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectra, X-ray powder diffraction (XRD) and magnetization versus magnetic (VSM) techniques, demonstrated sufficient catalytic active sites and photo-responsive sites. Among all the so-prepared catalysts, P[3SPA-2DABCO]@SiO2@Fe3O4 performs extremely well and can stabilize soybean oil-in-methanol Pickering emulsion for 24 h, achieving a biodiesel yield up to 98.2% at a catalyst dosage of 5 wt% after the reaction time of 5 h at 60 °C. Furthermore, the double responsive solid catalyst can be readily separated from the mixture of reaction by an external magnet and UV irradiation, and still presented superior catalytic activity after 6 cycles.

Abstract CBM reservoirs are extremely vulnerable to damage due to their complex pore structure. So, changing pore structures in CBM reservoirs is of vital importance for reducing reservoirs damage. Organic solvents have been considered as additives into fracturing fluids to enhance production because they can enhance the pore connectivity and loosening macromolecular network structure. It is thus of great interests to investigate how organic solvents (ethanol and ethylene glycol ether) change micropore structures and fluid distribution. In this study, samples were selected from different wells completed in No. 3 coal seam, Zhaozhuang minefield. Low-pressure nitrogen adsorption (LP-N2GA) experiments were conducted on coal samples to evaluate the changes in pore-structure parameters including specific surface area (SSA), pore diameter, and pore volume. NMR experiments were conducted on coal samples to evaluate the changes in fluid distribution. Analyzing the LP-N2GA results suggests ethylene glycol ether and ethanol can effectively increase SSA, pore diameter, and opening degree of pores in coal samples. Comparative analysis of NMR results indicates that ethylene glycol ether consistently reduces the irreducible water saturation (Swir) in samples. The average value of Swir of raw samples is 0.8670 and the average value of Swir of samples treated with ethylene glycol ether value is 0.7644. Considering the pore-structure alterations, this study demonstrates that ethylene glycol ether is more preferable for enhancing recovery from CBM reservoirs compared with ethanol.

Abstract Brown and Ladner's parameters have been compared with those of Williams for the same conditions. The combination of experimental data from 1H n.m.r. and 13C n.m.r. spectra gives the value of the Brown and Ladner's parameter H aru C ar . A comparison of the H aru C ar values was performed on a group of different coal oil samples.

Abstract Residues from the liquefaction of Black Thunder subbituminous and Illinois No. 6 bituminous coals in an autoclave and a bench unit were examined petrographically. Optical microscopy proved valuable for ranking the samples on the basis of overall coal conversion and presence of vitroplast, granular residue and inertinite. It was observed that in the autoclave that runs on Black Thunder coal, K 2 CO 3 was a superior water gas shift reaction catalyst to NaAlO 2 , or a combination of CS 2 and Fe or Mo catalysts. The amount of vitroplast showing vacuoles and cenospheric morphology in the residues was inversely related to the CO conversion, indicating that the mechanism of vitroplast dissolution is linked to the availability of active CO intermediates (e.g. formate ion, HCOO − ). A CO-steam mixture was more effective than syngas or pure H 2 and N 2 in increasing Black Thunder coal conversion, and resulted in greater morphological changes to the coal particles. In contrast, for Illinois No. 6 coal pure H 2 had a greater effect on coal solubilization and overall conversion than pure CO at the same temperature; this was attributed to the absence of carboxylates to react with the formate ions. Higher mesophase and coke contents were detected in some bench unit runs on Black Thunder coal that were operated in counterflow mode. Higher severity, poorer mixing, longer residence time and a reduction in pressure by almost 3.5 MPa are believed to be responsible for the retrogressive reactions forming mesospheres in these cases.

Abstract Bitumen recovery by steam-solvent coinjection involves the coupled thermal/compositional mechanisms for reduction of bitumen viscosity. Reliable design of such processes requires reservoir flow simulation based on a proper phase-behavior model so that the oleic-phase viscosity near the steam-chamber edge can be modeled reliably. However, the effect of bitumen characterization (e.g., the number of pseudo components used) on steam-solvent coinjection simulation has not been studied in detail, and can be realized only after running multiple reservoir simulations, which is time consuming. There are two main objectives in this paper. One is to develop a reliable method for bitumen characterization by improving the fluid characterization method that was recently developed based on perturbation from n-alkanes (PnA). The other is to develop a novel analytical method for assessing the sensitivity of a particular coinjection simulation to bitumen characterization without having to perform reservoir simulations. A simulation case study is given to validate this analytical method. A proper number of pseudo components for bitumen characterization cannot be determined without considering the effect of phase behavior on the oleic-phase viscosity at chamber-edge conditions in steam-solvent coinjection simulation. Results show that the analytical method developed in this research can detect the sensitivity of recovery simulation to bitumen characterization without performing multiple flow simulations using different sets of fluid models. The PnA-based method developed for bitumen characterization gives reliable predictions of phase behavior for bitumen/solvent mixtures with a small amount of experimental data.

Abstract The rate of oxygen consumption and the release of CO2 were studied using a low-temperature oxidation simulation system. Six model compounds with different functional groups and pore structures were used in the experiment. The results showed that the oxygen consumption rate of six model compounds was mainly controlled by pore diffusion; the release of CO2 for the carbon nanotube (CNT) model compounds CNTs-Mac and CNTs-Mes was controlled by chemical adsorption of oxygen-containing functional groups, while the CNTs-Mic compounds was by diffusion resistance in channels. The carboxyl group, where CO2 adsorbed, was the main adsorption site; this had a higher oxygen consumption rate than the hydroxyl group. Two different methods were employed in further studies to explore the relationship between CO2 and oxygen-containing functional groups: a quantum chemical simulation for basic structural units of lignite, and measuring the activation energy of two types of lignite pre-treated by different CO2 concentrations. Experimental results revealed that the O H bond of the carboxyl was longer than that of the hydroxyl, and the negative surface potential of the carboxyl was stronger than that of the hydroxyl. The non-covalent bond between the reactive group and coal macromolecule could be weakened due to the presence of CO2. Finally, there was a synergistic effect between 30% CO2 and active functional groups to promote low-temperature oxidation of lignite.

Abstract Interest in using unaltered vegetable oil as a fuel in diesel engines has experienced an increase due to uncertainty in the crude oil market supply and the detrimental effects petroleum fuels have on the environment. Unaltered vegetable oil blended with petroleum fuels is less expensive, uses less energy to produce and is more environmentally friendly compared to petroleum diesel or biodiesel. Here we investigate the engine performance of unaltered waste soybean oil blended with petroleum diesel and kerosene for three vehicles. Five biofuel blends ranging from 15% to 50% oil by volume were tested on a 2006 Jeep Liberty CRD, a 1999 Mercedes E300 and a 1984 Mercedes 300TD. A DynoJet 224x chassis dynamometer was used to test vehicle engine performance for horsepower and torque through a range of RPMs. Results for the Jeep showed a modest decrease in horsepower and torque compared to petroleum diesel ranging from 0.9% for the 15% oil blend to 5.0% lower for the 50% oil blend. However, a 30% oil blend showed statistically better performance (P