查看更多>>摘要：This review discusses the challenges of the preparation and investigation of adsorbents for high-performance and safe operation of natural gas (methane) storage/delivery systems. Currently, researchers have been paying increasing attention to coordination polymers distinguished by developed surface, very high porosity, and adjustable porous structure. This part, Part 2, of the review provides an analysis of the current state of research on the development of methane adsorbents based on highly porous metal-organic and covalent organic framework materials, hybrid composites, and a number of other structures. Emphasis is placed on modification methods for these materials, their structural design, and fine-tuning of pore size for the most efficient use of their nanoporous space for methane storage.
查看更多>>摘要：One of the promising technologies to concurrently recover and upgrade heavy oil is the novel Toe-to-Heel Air Injection (THAI) combined with CAtalytic upgrading PRocess In situ (CAPRI) process. With the add-on CAPRI, the produce oil is partially upgraded to medium or even light oil with American Petroleum Institute (API) gravity increase in range of 3°-7°, viscosity reduction 70-90% and 70-85% recovery of original oil in place. But the catalyst suffers severe deactivation due to active sites coverage and pore blockage caused by coke and heavy metal depositions. This review explores methods of extending catalyst longevity in in situ catalytic upgrading of heavy oil during THAI process to bridge the gap that has been left void for a long period of time, and to serve as a guide for the low-cost catalyst design in order to improve process economics. To direct future research, several approaches such as the use of a structured guard bed, nano-sized catalyst, engineered catalyst support and pore sizes, graded catalyst bed, hydrogen addition, hydrogen-donor solvents, and steam environments have been identified and explored to suppress coke formation during catalytic upgrading of heavy oil. In addition to considerations for catalyst design for in situ upgrading applications, the study also discusses the operation conditions and upgrading environment that minimize coke formation and optimize catalyst longevity in the THAI-CAPRI process and similar processes such as steam assisted gravity drainage (SAGD).
查看更多>>摘要：To improve the performance of asphalt, the modified asphalt was prepared by adding styrene-butadiene-styrene block, copolymer (SBS) and sulfur powders into the base asphalt. The storage behavior of asphalts was tested to optimize the quality of adding SBS and sulfur. The storage stability and viscoelastic properties of modified asphalts were also studied. The results showed that under the proportioning final addition of SBS and sulfur, the storage stability, the high and low-temperature performance of asphalt was greatly improved, making it possible to meet the stability requirements for high-temperature storage of asphalt. Additionally, only a small amount of acidic sulfur-containing gas such as H2S escaped during the modification process. The microscopic observation showed that the "sea-islands" form of SBS-modified asphalt was changed to a uniform and continuous dual-phase structure after sulfur addition. Finally, it was proposed that sulfur induced the chemical reaction between SBS and asphalt to form a stable network structure, which was the intrinsic mechanism to improve the performance of asphalt.
查看更多>>摘要：In this study, n-hexane-asphaltenes (X-A) and n-heptane-asphaltenes (P-A) were separated and collected by n-hexane and n-heptane respectively. The two asphaltenes were divided into six subtractions (A1-A6) by the mixed solvent (toluene/n-hexane or toluene/n-heptane). The differences between X-A and P-A were studied and the differences between subtractions were compared. And the effects of X-A, P-A and subtractions on oil-water interfacial tension (IFT) were evaluated. The content and polarity of X-A are greater than that of P-A. The ability of X-A reducing oil/water IFT is stronger than that of P-A. The structures of X-A and P-A were simply speculated by the improved B-L method (Bitumen-Liquid product method is used to calculate structural parameters). Both P-A and X-A are cata-condensed and they are mainly tricyclic-aromatics. Moreover, X-A is a kind of high condensation aromatic polymer with regular arrangement, short alkyl chains, low rigidity and more naphthenic rings. P-A is a kind of high condensation aromatic polymer with poor arrangement regularity, long alkyl chains, large rigidity, more aromatic rings but slightly less condensation degree than X-A.
查看更多>>摘要：Hydrostabilization of straight-run naphtha pyrolysis condensate in the presence of a commercial nickel-chromium catalyst at 80-120°C, hydrogen-to-feed ratio of 0.3-0.8 m~3/L, and process time of 30-120 min was studied. The hydrostabilized pyrocondensate yield increases with an increase in the hydrogen content. The degree of hydrogenation has pronounced temperature dependence at a low-hydrogen hydrogen-to-feed ratio, whereas with an increase in this ratio the temperature dependence levels off. A detailed study of the fractional and component composition of the hydrostabilized pyrocondensate revealed significant differences in the catalyst selectivity depending on the reaction conditions. Low process temperature and high hydrogen-to-feed ratio favor intense formation of aromatic hydrocarbons (at 100°C and hydrogen-to-feed ratio of 0.8 m~3/L, the yield was 82 wt %), whereas at elevated temperatures and low hydrogen content the formation intensity shifts toward isoparaffins (at 120°C and 0.5 m~3/L H2, the yield was 32 wt %). A possible hydrogenation mechanism ensuring the selectivity of the nickel-chromium catalyst in the process was outlined. The parameters of the fractional and hydrocarbon compositions and the octane numbers of the distillates obtained allow them to be suggested as components of motor fuels.
查看更多>>摘要：Conversion of mixtures of fuel oil with iron-containing substrates (carbon adsorbent and lignin, both modified with 0.5 wt % Fe) to hydrocarbon products and hydrogen was studied. The use of microwave radiation in the presence of the above-indicated iron-containing substrates capable of its absorption with the generation of breakdown phenomena and plasma is a promising approach to rapid processing of stable organic compounds of petroleum and natural origin into hydrocarbon products used in organic synthesis and for production of fuel components.
查看更多>>摘要：This study investigated the kinetic patterns of the liquid-phase Prins condensation of propylene with formaldehyde in the range of 120-180°C over H-MFI and H-BEA zeolites. The apparent reaction order with respect to formaldehyde was found to vary between 0.1 and 0.2 for H-BEA and to be close to zero for H-MFI. The apparent activation energy for H-MFI and H-BEA was 26.1 ±0.6 kJ/mol and 20.0±4.0 kJ/mol, respectively. Based on these results, the reaction was demonstrated to occur in the intradiffusion or transition region; the calculated Thiele modulus and effectiveness factor further confirmed this fact. The diffusion limitations were partially removed by raising the initial formaldehyde concentration, as indicated by an increase in the apparent order of formaldehyde conversion to 1.0 for H-BEA and to 0.4 in the H-MFI case. To describe the substrate transformations observed, a modernized reaction mechanism was proposed.
查看更多>>摘要：Mixed PMoV heteropoly acids with Keggin structures H_(3+x)PMo_(12-x)VxO_(40) (x = 1-6) and modified sulfide catalysts on their basis were synthesized, their physicochemical characteristics were determined, and their performance in the reactions of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of naphthalene was evaluated. Modification of the Mo-containing catalysts with vanadium by impregnation with a solution of mixed heteropoly acids was found to enhance their catalytic activity in the studied reactions, as well as to increase the selectivity for the direct hydrodesulfurization route of the DBT HDS reaction.
查看更多>>摘要：This study demonstrates the synthesis of titanium oxide-magnetite/chitosan nanocomposite (TiO2-MNPs/CT) where TiO2 nanoparticles were precipitated onto prepared MNPs followed by immobilization onto CT. The prepared nanocomposite was investigated using scanning electron microscopy, X-ray diffraction spectrometry, and Fourier transform infrared spectrometry. The nanocomposite was applied for adsorptive removal of naphthalene, which is the most prevalent compound of the most hazardous polycyclic aromatic hydrocarbon, from aqueous solutions. The parameters assumed to considerably controlling the removal process was optimized. The highest removal efficiency (98%) with the maximum adsorption capacity (49.7 mg/g) was obtained at pH 7, adsorbent concentration 2 g/L, and contact time 24 h. The experimental results were analyzed using isotherm models including Langmuir, Freundlich, and Dubinin-Radushkevich, which revealed multilayer adsorption with maximum adsorption capacity of 60.48 mg/g. The kinetic studies showed good fit for the experimental results with pseudo-second order model referring to the presence of chemical adsorption. Furthermore, the spent adsorbent particles were regenerated via shaking with ethanol for 60 min and studied in repeated adsorption cycles. Slight decrease after the fifth adsorption-regeneration cycle was observed, indicating good stability of the nanocomposite against regeneration.
查看更多>>摘要：This study reports rhamnolipid biosurfactant production from biodegradation of petroleum oil wastes using Pseudomonas aeruginosa ATCC 9027. Glycerol was added as an inducer to enhance the production of rhamnolipid. Tests were run on effluents with different initial oil concentrations (1, 1.5, and 2%) at two glycerol dosages (10 and 20% of the oil concentration in the effluent). A higher percentage removal of oil in the ensuing effluent (99.9% for both poly aromatic and poly aliphatic hydrocarbon fractions) was realized. Meanwhile, a high percentage yield of rhamnolipid (2.7 g/L) was observed. Optimization of the parameters affecting oil biodegradation; using the response surface methodology (RSM) and a Box-Behnken design, statistical analysis of the experimental data, was applied. The study showed that the optimum values for reaction time, crude oil percentage and glycerol addition were 240 h, 2 and 18.346%, respectively. These values were comparable to the values obtained from the experimental work.
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