In order to better deal with the oily sludge produced in the process of oil production, gathering and transportation as well as oil refining, and in line with the current development trend of environment⁃friendly chemicals in the petrochemical industry, it is very important to use environmentally friendly and low toxic and non⁃toxic chemical reagents in the neighborhood of sewage treatment. This paper introduces a new cleaning agent for oil sludge. Compared with the traditional cleaning agent, the new cleaning agent uses natural chemical derivatives (environmental friendly plant solvent is the main component), which has the characteristics of low toxicity, low pollution and high cleaning efficiency. The use temperature is 5~10 ℃ lower than the field use temperature, further reducing the use of energy. Under the synergism of composite cleaning agent, the residual oil rate in the cleaned sludge can be less than 2%, which has a wide and excellent application prospect.
The research progress of changing the final active phase of the catalyst by using complexing agents during the preparation of oil hydrodesulfurization catalysts is discussed. The common complexing agents and their effects on catalyst performance improvement under different usage methods are introduced. The effect of the complexing agent on the microstructure of the catalyst is systematically described, and the reason of the complexing agent can improve the performance of the catalyst is explained.
With the rapid development of industry, the negative impact of the use of fossil fuels on the ecological environment is becoming more and more prominent. Among them, CO2, as the main greenhouse gas, causes serious harm to global climate change. The selective hydrogenation of CO2 to methanol is one of the important ways to solve the greenhouse effect, develop green energy and realize sustainable economic development. Copper⁃based catalysts are widely employed for CO2 hydrogenation to methanol due to their excellent catalytic performance and low cost. The difference in reaction mechanism is due to the highly adjustable chemical and electronic properties of copper⁃based catalysts, resulting in the different catalytic performance. This article reviewed the representative reaction mechanism of selective hydrogenation of CO2 to methanol over copper⁃based catalysts was presented, aiming to provided a theoretical guidance for the design of efficient and stable copper⁃based catalysts.
The stringent environmental management of petrochemical industries requires high⁃efficient waste disposals and wastewater treatment. Value⁃added and all⁃component resource technologies were insufficient for petrochemical wastes. Moreover, the advanced treatment of petrochemical wastewaters was lack of highly active and low cost catalysts. Based on the compositions of petrochemical wastes and ozonation catalysts, the present overview proposed that petrochemical wastewaters were treated using petrochemical wastes derived catalysts. Petrochemical wastes and wastewaters management might be synchronously improved by employing a "wastes⁃treat⁃wastes" strategy.
Molecular thermodynamic models and the properties of fluid phase equilibria are necessary to the design, running, control and optimization of industrial process and furthermore its precision and reliability are directly related to the modeling and optimization results of process simulation. In this context, an equation of state with variable range for square⁃well potential (SWCF⁃VR) was developed based on the statistical association fluid theory and applied to represent the thermodynamic properties like vapor⁃liquid equilibria (VLE), liquid⁃liquid equilibria, solid⁃liquid equilibria, enthalpy of vaporization or mixing and so on for traditional fluids, associated fluids, electrolyte solutions, ionic liquids, polymers, etc. At the same time, the equation of sate combining with surface tension and viscosity can be used to predict and calculate the transfer properties of the mixture such as surface tension and viscosity successfully. The salient feature in our model was that transferable molecular parameters fitted from experimental phase equilibria data or predicted from group contribution method or solvation calculation were used. Meanwhile, the test of theoretical model and determination of molecular parameters in SWCF⁃VR were carried out always based on experimental thermodynamic data. Thus, an online platform for fluid phase equilibria (www.equilibria.cn) were developed, where the details about phase behavior conception, classification and applications were summarized, and data searching systems and some softwares for VLE calculation provided. The mentioned thermodynamic model and online platform in this work could be well used for process design, modeling and optimization.
The morphological identification and molecular dimension estimation of organochlorine compounds (OCCs) in two different naphtha samples were performed. The analysis result of gas chromatography equipped with an electron capture detector indicates that the chloroaromatics are predominant OCCs in the two naphtha samples, and a small amount of chloroolefins and chloroalkanes coexisted with them. The main OCCs (>3 mg/L) in naphtha I are 1,2⁃dichlorobenzene, 1,4⁃dichlorobenzene, 1,6⁃dichlorohexane, 1,1⁃dichloroethylene, 2⁃chloroethylbenzene and 1,2⁃dichloropropane, and that in naphtha II are 1,2⁃dichloropropane and 1,4⁃dichlorobenzene. The three⁃dimensional dimension of 14 identified OCCs are determined by softwares, whose minimum cross⁃sectional diameter is between 0.4 nm and 1.0 nm by further estimation. The high abundance of OCCs, which easily are converted to corrosive hydrogen chloride and ammonium chloride during processing, in naphtha may be a primary cause of increased malfunction in naphtha prehydrogenation unit. The porous adsorption material with micropore close to the molecular diameter is beneficial for the adsorption removal of OCCs.
A new type of waterborne self⁃emulsifying polyester⁃poly was synthesized from itaconic acid (IA), 1,4⁃butanediol (BDO), sodium itaconate (IsNa) and undecylenic acid (UA). (Itaconic acid butylene glycol⁃co⁃undecenoic acid butylene glycol) ester (PBIINa⁃UA), which could be cured into a film by a UV⁃induced thiol⁃ene click reaction. The structure, interfacial tension and tensile strength of the cured film were analyzed by infrared spectrometer, nuclear magnetic resonance instrument, interfacial tension meter and electronic universal tensile machine. The results show that the synthesized aqueous polyester has a certain self⁃emulsification performance, and the paint film obtained by the thiol⁃ene reaction curing has lower oxygen inhibition than the conventional heat curing paint film. When the ratio of sulfonic acid group to double bond in PBIINa⁃UA is 1∶10, and the mass fraction of initiator is 1.5%, the obtained lacquer film get the best performance.
Among the anode materials, silicon is an ideal anode material for high⁃energy and high⁃power lithium ion batteries because of its exceptionally high theoretical capacity (4 200 mA·h/g) and low operation potential (~0.4 V vs Li/Li+). However, the huge volume change of silicon anode material during Li+ insertion/extraction processes causes serious structural damage and rapid capacity decay. In this paper, the lithium storage mechanism, structure evolution process, interface reaction and dynamic behavior of silicon anode material were explored. The recent progress of surface and interface modification methods, focusing on silicon electrode surface modification, electrolyte optimization and binder development, and their applications in lithium⁃ion batteries were reviewed. Challenges and perspectives about the future development of the surface and interface control of silicon anode were proposed.
Lithium⁃sulfur batteries are expected to become the next generation of specific energy storage batteries to replace lithium⁃ion batteries due to their significant advantages such as high specific capacity, high energy density, low cost, and environmental friendliness. However, the practical application of lithium⁃sulfur batteries is severely limited by a series of problems existing in electrode materials, such as lower ion/electron conductivity, shuttle effect of polysulfides, large volume changes during charge and discharge, and the stability of lithium anodes and so on. Combining sulfur with various carrier materials to improve the utilization of active materials and battery cycle stability has become a current research hotspot. Among the reported carrier materials, metal organic frameworks with rich pores and open active sites and their derivative materials have attracted wide attention because of their excellent structural characteristics. This review summarized the recent research progress of metal organic frameworks and their derivatives in improving the cycle stability of sulfur cathodes, and prospected its development trends in lithium⁃sulfur batteries.
A as the most abundant renewable resource on the earth, biomass has the advantages of low cost and no increase of atmospheric CO2 content, its application has become a research hotspot in the field of energy utilization and environmental protection. Native biomass can be prepared from a variety of functional carbon materials via Hydrothermal Carbonization (HTC). This paper summarized the research progress in the preparation of carbon materials with wide range of uses by using HTC method from raw biomass. The application of carbon materials based on HTC in gas liquid adsorption, magnetic carbon materials, battery materials and other fields were also analyzed and prospected.
Ni/Al⁃LDHs/rGO composites with various GO contents (0, 0.2%, 0.5%, 0.8% and 1.0%) were prepared by a facile homogeneous precipitation method with Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea, and GO as raw materials. The microstructure and surface morphology of the prepared samples were characterized by XRD, FT⁃IR, TGA, and FESEM; the electrochemical properties of the samples as anode materials for Ni⁃MH battery were studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge⁃discharge tests. The results demonstrated that the electrochemical performance of Ni/Al⁃LDHs can be significantly improved by incorporating rGO. Among the five samples, the Ni/Al⁃LDHs/rGO composite with GO content of 0.8% exhibited the most excellent comprehensive electrochemical performance.For example, at the high current density of 2 000 mA/g, it still delivered a specific discharge capacity of 288 mA·h/g, which is 40.5% higher than that (205 mA·h/g) of the pure Ni/Al⁃LDHs sample.
The China National Petroleum Pipeline Network Group Co., Ltd. was established on December 9, 2019, which marked the separation of large⁃scale oil and gas pipeline network from petroleum and petrochemical companies, followed by a new stage of independent operation of oil and gas pipeline network in China. As an important part of the oil and gas pipeline network, similar to the crude oil pipeline network and the natural gas pipeline network, the refined oil pipeline will experience a major change in its operating model after reorganization into the National Petroleum Pipeline Network Group Co., Ltd.This paper analyzes the differences between several typical operating modes of refined oil products pipeline, explains the shortcomings in the transformation and adaptability of refined oil pipelines in China. The reform methods of refined oil products pipeline are discussed, and the corresponding suggestions are put forward.
In order to improve the methane storage in porous media under mild conditions, the storage characteristics of methane in Mil⁃101 (Cr) were studied based on adsorption water method.MIL⁃101 (Cr) was prepared and characterized. Methane adsorption experiments were performed at 271.15 K and 0～7.0 MPa with different water contents. The particle size of the synthesized material was uniform, grain size range was 100～150 nm, and almost without impurities. The pore size was mainly distributed in the range of 1.7 nm to 3.6 nm. The results of adsorption experiments show that: MIL⁃101 (Cr) adsorbs more methane under the condition of water, and with the increase of the water content, the amount of methane adsorption increases. The pressure required for nucleation in porous media is higher than that for bulk system, and the greater the water content is, the higher the critical pressure is. The MOF material used in the experiment still has good adsorption capacity after repeated regeneration. The research results have certain significance for increasing the natural gas storage capacity.
Temporary plugging and diverting fracturing technique is an essential way to improve the refracturing fracture network of shale reservoirs. However, there are still some uncertainty factors for this fracturing technique over the influence on fracture propagation of shale hydraulic fracturing. Therefore,based on the indoor true tri⁃axial hydraulic fracturing physical experiment, this paper studied and analyzed the fracture initiation and diversion mechanism under the condition of differential stress and pumping rate. The index of fracture stimulation area (SRA) was utilized to represent the hydraulic fracturing effect quantificationally. The results show that: the temporary plugging agent, practically, could plug the pre⁃fractured fracture till the pressure to a certain value, so as to induce the diverting of hydraulic fracture in the channel from pre⁃fractured fracture or simulate the primary natural fracture network, which improve the complexity of the fracture morphology. Ultimately, there are four patterns of hydraulic fracture including sidestep⁃shaped fracture, transvers fracture with stimulated⁃natural weak discontinuities, simple multi⁃fracture and complicated multi⁃fracture network. The temporary plugging agent would block pre⁃opened natural fractures and stimulate the skewed new fracture when the horizontal differential stress is less than 12 MPa. As the differential stress is higher than 15 MPa, it is hard to simulate the natural fractures and the temporary plugging would block the pre⁃fractured transversal fracture, parallel to which a new fracture formed. Enhancing the fluid pumping rate could improve the activation probability of discontinuities, simultaneously, increase the fracture network complexity.
Friction stir welding (FSW) involves temperature, mechanics, metallurgy, and their interactions, which has become a revolutionary green welding technique over the past two decades because of the low peak temperature, severe plastic deformation, and high⁃quality joint. In order to further broaden its application in manufacturing fields, it was necessary to break through the technical barriers of inherent issues. Based on the inherent issues of weld thinning, keyhole and defects quasi⁃equal strength repairing, back⁃supporting and high⁃quality welding of dissimilar materials (such as dissimilar metals and metals/polymers), this paper reviewed the development of FSW innovative technology, which had practical significance for improving joint forming, realizing high⁃reliability joining and expanding engineering application.
The effect of ambient condition on the atomization characteristics were numerically simulated by using centrifugal nozzle as the research object, the influence of ambient air pressure and temperature on atomization characteristics parameters such as oil film thickness and atomization angle were obtained.With the FLUENT used,when the injection pressure was 4.0 MPa, the fuel temperature is 100 ℃,the ambient temperature from －50 ℃ to 400 ℃and the ambient pressure in the range of 0.1～3.0 MPa were numerically simulated.The results show that when the ambient pressure is constant, the temperature increases, the air density decreases, the fuel evaporation intensifies, the gas phase fuel ratio increases, and the atomization effect increases. When the ambient temperature is constant, the environmental pressure increases, the air density increases, the crushing occurs earlier, the oil film thickness increases, and the liquid phase fuel ratio increases, although the spray cone angle and the interaction between oil and gas increase, but it is not conducive to fuel atomization.
A new fault location method was proposed to solve the problem of active distribution network fault location caused by the increasing penetration of distributed generation and the increasing scale of distribution network.Considering the characteristics of increasing distribution generations penetration, the distribution generations was connected to the distribution network in the form of a micro⁃grid. A switching function that took into account the operating status of the micro⁃grid is established, and a linear integer programming model suitable for fault location was constructed on this basis. A T⁃type classification method was proposed to solve the problem of long time⁃consuming fault location. The principle was to select several first nodes downstream of the main substation and the T⁃type node as the demarcation points, so that the distribution network was divided into multiple regions. Finally, the fault region and fault section were located by linear integer programming. Simulation results show that the proposed method can locate the fault section quickly and accurately, and has strong robustness.
A ground⁃based infrared radiation characteristic measurement system not only undertakes the measurement of radiation characteristic, but also realizes the imaging in outfield. However, as for the manufacturing defects of the infrared focal the existing plane and the thermal radiation of system, it leads to the phenomenon of non⁃uniformity. Considering that the limitations of traditional non⁃uniformity correction algorithms, a variable integration time non⁃uniformity correction algorithm based on calibration was proposed in this paper. To confirm the effect of the proposed algorithm，the verification experiment based on 600 mm aperture mid⁃infrared radiation measurement system. The experimental results show that the original image non⁃uniformity under 2.5 ms and 3.0 ms is reduced from 3.69% to 0.22%. It is confirmed that the proposed algorithm has good correction effect and has engineering application significance.
