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• The copolymerization behavior of ETR and BTR and the characteristics of the product asphalt was studied. • The polymerization mechanism of ETR and BTR was inferred based on the molecular bulky structure and linear structure rules. • The role of BTR in improving the softening point of asphalt products was revealed. • A high strength carbon fiber was prepared using two low-cost residual oils of ETR and BTR. Carbon fiber prepared from asphalt may be a critical type of low-weight chemical material of excellent mechanical performances. Here, an isotropic spinnable asphalt (EBA) was prepared from ethylene tar residue (ETR) by a two-step method of bio tar residue (BTR) through co-polymerization-air blowing, and isotropic asphalt carbon fibers were prepared from the product asphalt. The main types of molecules contained in the two feedstocks were determined by 1H NMR and LDI-TOF MS analyses. The co-polymerization behavior and thermal stability of the asphalt blends were analyzed using polarized light microscopy and thermogravimetric analyzer, respectively. Finally, the morphology and mechanical properties of carbon fibers made from EBA were evaluated by scanning electron microscope and universal testing machine. The results show that BTR contains much more oxygen-containing functional groups and unique long-chain sawtooth molecular structure; the former can promote the reactivity of the co-polymerization reaction, and the latter can limit the formation of large-plane cyclic aromatic hydrocarbon polymers due to the spatial resistance effect to greatly reduce the content of the mesophase. The softening point of the product asphalt shows a tendency of increasing and then decreasing with the increase of the proportion of BTR in the raw material mixture, and a reaction mechanism based on linear and bulky molecules is proposed to explain it by analogy with the structure of macromolecules. Consequently, the EBA made from a mixture of ETR and BTR at ideal moderate proportions has excellent performance in terms of softening point and mesophase content than ETRO made from ETR alone, and the carbon fiber made has a high tensile strength of 1.82 GPa with an elastic modulus of 38.9 GPa, which has reached the level of high tensile strength carbon fiber. Therefore, the use of inexpensive renewable energy bio-asphalt in the modification of heavy oil to obtain high softening point isotropic asphalt for preparing isotropic carbon fiber with excellent properties is achievable. [ABSTRACT FROM AUTHOR]

Increasing studies have highlighted that the remarkable inherent uncertainty in design flood hydrograph (DFH) can potentially undermine flood management decisions. In order to quantitatively trace the propagation of DFH uncertainty in reservoir flood control system, we propose a novel methodological framework including three corn parts. First, a copula-based DFH estimation model integrating Bayes' theorem is presented to estimate DFH under model parameter uncertainty. Second, we perform an optimal reservoir operation model for flood control (OROM FC) with uncertain DFH as input variable to derive reservoir flood control operations (i.e. output variable). Third, an information theory-based model is designed to trace the DFH uncertainty propagation in reservoir flood control system. A reservoir flood control system in the Han River basin in China is selected as case study. Related results indicate that uncertainty in reservoir flood control operations reduces in comparison with the remarkable uncertainty in DFH due to the performance of the OROM FC. Specifically, uncertainty in reservoir flood control operations in periods close to peak flow is much smaller compared with that in other periods. The phenomenon further highlights the importance of reservoir flood control operations during periods prior to peak flow. Additionally, we find that uncertainty in flood peak of DFH is the dominant factor affecting reservoir flood control operations compared with that in flood volume of DFH. Moreover, we explore the impact of reservoir flood control capacity on reservoir flood operations in the context of DFH uncertainty. An interesting linear expression is found and fitted for identifying design flood events inducing reservoir overtopping under specific reservoir flood control capacity. • The uncertain design flood hydrographs (DFH) are obtained through a copula-based model integrating Bayes' theorem. • An information theory-based approach is designed to perform uncertainty quantification and propagation analysis. • Uncertainty in reservoir flood control operations reduces in comparison with the remarkable uncertainty in DFH. [ABSTRACT FROM AUTHOR]

Plants can absorb heavy metals from wastewater due to their biological characteristics, and can evenly disperse these metals into plants. Adsorbents prepared by pyrolysis of metal-rich plants have the advantage of uniform metal loading and small metal particles. Therefore, in this study, Pistia stratiotes was cultured in six monometallic solutions of the same concentration to obtain a monometallic desulfurization adsorbent (ACA-I); after screening, culture in three metal solutions of Ni-Co, Ni-Cu and Co-Cu to obtain bimetallic desulfurization adsorbent (ACA-II). The results of TEM and SEM showed that the diameter of metal nanoparticles supported by ACA-II was smaller and more uniform. The adsorption desulfurization performance of PSLAC-Co-Ni, PSLAC-Cu-Ni and PSLAC-Co-Cu was 87 mg g−1, 83 mg g−1 and 80 mg g−1, respectively, which were better than that of ACA-I. However, the physical structures as well as the adsorption desulfurization performance of ACA-II and ACA-I were better than those of adsorbents prepared by conventional methods. This simultaneously solves environmental problems such as heavy metal pollution of water bodies, treatment of metal-rich plants and excessive sulfur content in fuel oil. This study provides a new idea for the preparation and use of loaded adsorbents, and also provides some data support for further industrial applications. [Display omitted] • The desulfurization performance of ACA-II is better than that of ACA-I. • PSLAC-Co-Ni has the highest adsorption performance on DBT. • The metal active sites can effectively enhance the desulfurization performance. • Loading of bimetals facilitates the dispersion of metal active sites. [ABSTRACT FROM AUTHOR]

• Sequential pretreatments were developed for the high-value utilization of slurry oil. • Comprehensive properties of feedstock were improved for the need of carbon materials. • Carbon materials, possessing better performance for application, were synthesized. FCC slurry oil (SO) is an important and yield-rich by-product of the FCC process, which can be regarded as the raw material of high-value-added carbonaceous products due to its abundant concentration of aromatic components, but essential pretreatments and purifications for SO are required before carbonization to eliminate the adverse factors. Appropriate sequential pretreatments aimed at achieving the high-value utilization of SO have been developed, and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR, 13C NMR) were implemented for the systematical properties analyses of SO and its derivatives after sequential pretreatments. Polarized-light microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to evaluate the microstructures and microcrystal parameters of intermediate species and final products during carbonization. Through the varying degrees of sequential pretreatments, the comprehensive properties of feedstocks were improved gradually which further led to the diverse development of carbonaceous mesophase at the early stage of carbonization. Furthermore, ordinary or superior needle coke can be synthesized from the obtained oil samples during sequential pretreatments. The synthesized needle coke had suitable performance for the application in anode material of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• Comparative characterizations and MG adsorption evaluation of PUPW-ACs were implemented. • The maximum adsorption capacity of MG on the champion PUPW-AC was up to 1428 mg g−1, highly superior to other ACs. • The adsorption drive forces were electrostatic attraction, oxygen-containing groups, and π-π interaction. • The PUPW-AC could serve as a promising adsorbent for MG removal from aqueous systems. Upcycling polyurethane plastic waste (PUPW) into activated carbon (AC) for the removal of malachite green dye (MG) in wastewater via physical adsorption could provide abundant low-cost adsorbent and facilitate treatment of plastic waste and wastewater simultaneously. For this reason, four types of PUPW-ACs were prepared by various preparation procedures. The properties of PUPW-ACs were characterized using BET, FT-IR, XPS, Raman spectroscopy, and XRD; the adsorption performances of PUPW-ACs were also evaluated. It was found that the properties of PUPW-ACs varied in terms of porosity, microstructures, and surface chemistry. Intentional modulation of PUPW-AC would be possible via preparation procedure adjustment. Two-step preparation procedure (1. carbonization; 2. activation) was recommended to acquire PUPW-AC (i.e., PUPW-AC-C-A) with a high specific surface area of 1034 m2 g−1 and the maximum MG adsorption capacity of 1428 mg g-1. Electrostatic attraction, oxygen-containing groups (especially carboxyl functional groups), and π–π interaction were believed to contribute to the adsorption driving force for the outstanding adsorption performance of MG on PUPW-AC-C-A. The PUPW-AC prepared from PUPW could serve as a promising adsorbent used in MG dye removal from aqueous systems. [ABSTRACT FROM AUTHOR]

• SO was utilized to produce MCMBs instead of being burned as carbonaceous fuel oil. • D-SO-MCMBs showed obvious coalescence while SBHD-SO-MCMBs have no coalescence. • The olefins produced during thermal reaction may promote the coalescence of MCMBs. • Fewer olefins and more naphthenes in SBHD-SO were facilitated to MCMBs preparation. • SBHD-SO-MCMBs best meet the requirement of the lithium-ion battery anode material. Slurry oil (SO) as the starting feedstock for the preparation of mesocarbon microbeads (MCMBs), an excellent carbonaceous anode material, is of significant commercial value and environmentally friendly. In this study, the MCMBs were prepared by thermal polymerization of SO after modification through suspended-bed hydrofining followed by distillation (SBHD). The results showed that SBHD is fully competent in saturating olefins and increasing naphthenes of SO simultaneously and thus bringing forth more naphthenic hydrocarbons and less olefins in SBHD-SO, which is indeed beneficial to the preparation of MCMBs with better morphology and more uniform size distribution. More interestingly, there was evident coalescence between MCMBs prepared from D-SO during the growth process due to the existence of abundant active groups on the MCMBs' surfaces, whereas the MCMBs prepared from SBHD-SO grew via absorbing the mesogen molecules in the mother liquor and there was no obvious coalescence between mesophase spheres. Moreover, the anode performance showed that the MCMBs prepared from SBHD-SO can deliver the highest discharge specific capacity of 315 mAh/g at a current density of 500 mA/g and an excellent stability of cycle performance. Thereby, the MCMBs prepared from SBHD-SO best meet the application requirements. This study paves a new strategy for the efficient preparation of MCMBs by using SO, which may expand the application prospect of SO. [ABSTRACT FROM AUTHOR]

• A Bayesian information-theoretic approach for disclosing design flood uncertainty. • How the parameter uncertainty is propagated to bivariate design flood is uncovered. • Uncertainty in design flood is enormous and increases along with return period. • Parameters of marginal distributions contribute most to design flood uncertainty. Copula-based statistical model has been extensively used to characterize the joint probability behaviors of extreme hydro-climatic design events, such as bivariate design floods. However, parameter uncertainty, not desirably but inevitably, accompanies the copula-based design flood estimation (CDFE) model which makes the inference results of design flood ambiguous. In this paper, we develop a Bayesian information-theoretic (BIT) approach to disclose design flood uncertainty arising from parameter uncertainty in CDFE model and furthermore examine how the parameter uncertainty is propagated to design flood estimation. Two catchments located in the Yellow River Basin, China, are selected as study regions. The research we have done indicates that design flood uncertainty is considerably large under parameter uncertainty. Worse still, the uncertainty in design flood increases along with the return period, thus making the design flood inference more ambiguous. Specifically, shape and scale parameters of marginal distributions have the largest contribution to the design flood uncertainty, followed by copula parameter, finally the location parameter of marginal distribution. Furthermore, the interaction between some parameters has dominant effect on design flood uncertainty compared with the individual effect of these parameters. These findings will enable better understanding the design flood uncertainty under parameter uncertainty. Moreover, the proposed BIT approach also offers a promising technical reference for design estimation of other types of extreme hydrological events, not limited to the design flood. [ABSTRACT FROM AUTHOR]

Olefin as one of the most important product molecules of FCC process drastically affects DO's thermal stability and the preparation of mesophase pitch due to its high reactivity. Several selected olefins have been added to hydrotreated DO for mesophase pitch preparation, crystal structures of their products had different degrees of damage and all of them were extremely uneven for size distribution. • Effects of olefins on mesophase pitch preparation were studied for the first time. • Crystal structure of mesophase pitch had been damage due to the addition of olefin. • Conjugated olefin had a much stronger effect on the development of mesophase pitch. Olefin as one of the most important product molecules of fluidized catalytic cracking (FCC) process is widely distributed in FCC decant oil (DO), and drastically affects DO's thermal stability and the preparation of mesophase pitch due to its high reactivity. Mild hydrogenation was performed on a low-sulfur DO to stabilize the unstable molecules, i.e., olefins. Several selected olefins (including monoolefinic and conjugated) were added to the hydrotreated DO to investigate their effects on thermal stability and mesophase pitch preparation. Bromine number, diene value, proton magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) were used to characterize DO before and after hydrotreatment, and X-ray diffraction (XRD) and polarized optical microscope were used to detect the structure of mesophase pitch. Thermal stability of raw material was significantly enhanced through hydrotreatment where macromolecular aromatic hydrocarbons underwent partial hydrogenation, without over-hydrogenation. Influence of 1-octene, styrene and trans-stilbene on thermal stability of oil samples was enhanced successively due to the electron delocalization of conjugated olefins, and the effect of the amount of olefins added were significant. Olefins added to hydrotreated DO had different degrees of degradation on the crystal structures of mesophase pitch, and conjugated olefins had a much stronger effect on the development of mesophase pitch where the domain structures appeared in advance, with coarse-grained mosaic structure also interspersed in them. [ABSTRACT FROM AUTHOR]

Slurry-bed hydrotreating coupled with distillation may optimize the compositions and properties of heavy oils, including improving their hydrogen-donating ability of heavy oils. The effects of slurry-bed hydrotreating coupled with distillation on the compositions and properties of FCC slurry oil were determined by various analytical methods. 1H NMR was used to characterize and determine the hydrogen-donating ability of FCC slurry oil, and the structure of mesophase pitches formed by carbonization of FCC slurry oil were characterized by polarizing microscope, softening point and X-ray diffraction method. The results showed that slurry-bed hydrotreating obviously prevents FCC slurry oil from coking behavior during the distillation process, and overall compositions and properties of FCC slurry oil after optimization meet the requirements for producing mesophase pitch. Most importantly, the hydrogen-donating ability of FCC slurry was drastically increased from 0.392 (mg-H/g-Oil) to 1.917 (mg-H/g-Oil). In turn, in contrast with the raw FCC slurry oil, the slurry oil after the slurry-bed hydrotreating coupled with distillation easily formed mesophase pitch with a large flow domain structure, low softening point, and ordered microcrystal structure through carbonization. Thus, the purpose of preparing high-quality mesophase pitch was achieved. [ABSTRACT FROM AUTHOR]

Power system flexibility refers to the ability to respond to changing net loads within a predefined timeframe. The main causes of flexible demand are resource and load uncertainties. The joint interaction of resource and load uncertainty makes flexible demand more complex. Accurately assessing the power system flexibility and promoting flexible supply are important for maintaining grid safety and stability. In this study, a joint probability distribution for intermittent renewable energy sources (IRES) output and load forecast deviation is proposed. Subsequently, an optimal dispatch model that considers flexible demand and hydropower flexible supply is built to improve the operation scheme of flexible resources. A hydropower dispatch model that does not consider the probability of IRES output and load forecast deviation is used as the contrast model. A comparison of the results shows that the optimal dispatch model is more beneficial for maintaining grid safety and stability. The results show that the maximum upward adjustment flexible (UAF) margin of the optimal dispatch model of the Yalong River Downstream is 376 MW, whereas the maximum downward adjustment flexible (DAF) margin is 197 MW. This implies that a greater UAF supply is required in the case study to satisfy the power system flexible demand. • A quantitative method for power system flexibility is proposed. • A joint probability distribution considering resource and load uncertainties is presented. • An optimal dispatch model considering flexible margins is proposed. [ABSTRACT FROM AUTHOR]

• ISGWM can describe the processes of surface water and groundwater accurately. • ISGWM coupled the optimal allocation and scheduling model. • Ecological water supply to regulate PWTD concentrated in flood season (Jul.-Oct.). • Agricultural water supply and PWTD both influenced by the uniformity of inflow. • Groundwater exploitation controlled difference between PWTD and target below 1 m. Balancing the water consumption of agricultural and ecological is the key point of sustainable social and economic development in an inland river basin. The growth of desert riparian forests in inland river basins mainly depends on a certain phreatic water table depth (PWTD). The main object of this study was to allocate and schedule water resources to regulate the PWTD and satisfy agricultural water demand. Therefore, a multi-objective double layer optimal allocation and scheduling framework based on the computationally efficient integrated surface water-groundwater model (ISGWM), which can simulate the surface water processes, groundwater recharge and discharge processes, and PWTD changes, was constructed and applied to the mainstream of Tarim River Basin (TRB). The top layer model of the framework is an optimal ecological water allocation model, and its optimal allocation results are used as the initial solution of the bottom layer model. The results show that under 5 different inflow frequencies, the agricultural water shortage rate is 0, 17.38 %, 17.41 %, 14.06 %, and 19.94 %, respectively. The PWTD regulation has a great performance. After the optimal scheduling, the proportions of good growth of the control area behind the gate under different inflow frequencies were 98.18 %, 98.18 %, 98.18 %, 90.91 %, and 94.55 %. Agricultural water shortage is mainly due to the non-uniformity distribution of intra-annual inflow and the lack of controlling hydraulic engineering. The regulation of PWTD can guarantee the growth of desert riparian forests on both sides of the mainstream of TRB. Besides, we explored the feasibility of exploiting groundwater to supplement agricultural water consumption. The groundwater exploitation should be controlled within the scope of not causing excessive increase of PWTD (difference between PWTD and target depth <1 m), due to the groundwater exploitation to supplement agricultural water will lead to the increase of PWTD. Overall, this framework, which regulates the PWTD with the change of ecological water supply based on the ISGWM , provides a new idea for the allocation and scheduling of agricultural and ecological water resources in arid inland river basins. It also provides a new method for the coupled cooperative operation of surface water and groundwater. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A CAPEO hemostatic powder was synthesized via a low-temperature plasma irradiation (LTPI) technique. • The hydrophilicity of CAPEO was improved by grafting –COOH and –NH 2. • The hemostatic ability of CAPEO was proved by in vitro and in vivo studies. • CAPEO could promote re-epithelialization, collagen deposition, and wound healing in a rat skin wound model. The development of a hemostatic material capable of controlling substantial blood loss in wound healing scenarios remains a critical challenge in clinical practice. Herein, we treated polyethylene oxide (PEO) with low-temperature plasma irradiation (LTPI) technology in the air, and the modified PEO (CAPEO) was obtained with carboxyl (–COOH) and amine (–NH 2) groups. Notably, CAPEO exhibited excellent hydrophilicity, great cytocompatibility, and blood compatibility. Platelets could be activated more and clotting time could be shorter with the treatment of CAPEO than with PEO. More importantly, in the rat liver hemorrhage model, the blood loss in CAPEO (95.8 mg) was less than in PEO (144.2 mg). Moreover, in vivo investigation of skin wound repair, CAPEO could promote epidermal regeneration and collagen deposition, thereby accelerating wound healing. These findings disclose that CAPEO holds great potential for hemostasis and wound healing. [ABSTRACT FROM AUTHOR]

The load distribution of cascade hydropower stations is associated with the safe operation of the hydropower stations and power grids. The conventional load distribution of cascade hydropower stations does not consider the synchronous operation of the water level. The inconsistent water level variation process of cascade hydropower stations is not conducive to the safe operation of hydropower stations and power grids. Therefore, the main purpose of this paper is to introduce the concept of equal reservoir full storage rate (ERFSR) to guide the load distribution of cascade hydropower stations. In addition, hydropower is used for new energy consumption considering the advantages of the rapid start-stop in hydropower units. The load distribution model of cascade hydropower stations is established, and three cases are set to verify the universality of the proposed model in the upper reaches of the Yellow River. The results show that (1) The concept of ERFSR can effectively guide load distribution and realize water level synchronization of cascade hydropower stations. (2) The output process of each hydropower station can be basically consistent with the load process to achieve synchronous peak shaving. (3) New energy consumption has little effect on the daily water consumption of downstream cascade hydropower stations. [ABSTRACT FROM AUTHOR]

Hydropower plays an extremely important role in the energy market with the increasing energy demand. The intra-annual runoff distribution (IARD) in the hydrological year has an important impact on the energy generation of cascade hydropower plants (CHP). This study evaluated the non-uniformity of IARD of the Datong River basin (DRB) in the hydrological year. The optimal operation model of CHP was constructed based on the genetic algorithm to investigate the impact of the non-uniformity of IARD on the energy generation of CHP. This study shows the following: 1) The observed runoff series has a decreasing trend, the non-uniformity of IARD has an increasing trend overall. 2) The energy generation of CHP shows a weak decreasing trend affected by the decrease of runoff and the increase of non-uniformity. 3) With or without water diversion, the CHP energy generation decreases with the increase of non-uniformity of IARD. 4) The difference of energy generation of CHP between consideration or not the water diversion is about 400 GWh when the inflow frequency is less than 50%. 5) The impact of non-uniformity of IARD on energy generation will be greater with the inflow increasing. This study can provide theoretical support for the water resources management and operation of CHP. • The non-uniformity of IARD was systematically evaluated. • Evaluating the impact of non-uniformity of IARD on energy generation of CHP. • Higher impact of non-uniformity of IARD on energy generation with greater inflow. • Strong correlation degree between the energy generation and the non-uniformity of IARD. • Water diversion causes about energy generation economic loss of 120 million CNY in the DRB. [ABSTRACT FROM AUTHOR]

The hydro-wind-PV-battery complementary operation has the potential to increase the integration of renewable energy sources into power grid. Nevertheless, the determination of the optimal capacity configuration mode and size for a hydro-wind-PV-battery complementary system (HWPBS) remains a persistent challenge. This study proposes a capacity planning framework for the HWPBS considering the characteristics of multi-energy integration to power grid. First, the centralized (CCP) and distributed (DCP) configuration patterns considering the ways of multi-energy integration into power grid are proposed to explore the optimal capacity configuration mode. Second, considering the randomness of incoming water of hydropower stations, a scenario analysis technique is proposed to obtain the typical inflow scenarios. Then, with the objectives of maximizing expected renewable generation and minimizing expected power abandonment and load loss, the capacity configuration models for the HWPBS under the CCP and DCP are developed. A load reconstruction method is proposed to reduce the computational burden. The parallelogram method is implemented to linearize the hydropower production model. Additionally, a set of indicators are proposed to evaluate the economy and reliability of the HWPBS. The proposed framework is applied to the Yalong River Basin. The results show that: the wind-PV configuration capacity is affected by load demand, battery storage and configuration patterns. The load demand process with better correlation to wind-PV output is advantageous for integrating wind and solar resources. Battery storage can effectively reduce power abandonment and load loss, and the configuration pattern has a significant impact on the final capacity of wind-PV power. The capacity configuration method of the hydro-wind-PV-battery complementary system. [Display omitted] • Considering the characteristics of multi-energy integration into power grid, the capacity configuration models for the HWPBS under the CCP and DCP are proposed. • The CCP is more favorable for the large-scale development of wind-PV power than the DCP. • The configuration sizes of the wind, PV, and battery storage in the Yalong river basin are determined. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The morphological characteristics of petroleum cokes differ apparently from each other. • FWHM of D 1350 is more appropriate than I D1350 / I G1580 for morphology criterion. • An explicitly Growth/Sigmoidal relationship between OTI and FWHM of D 1350 was observed. • RS could be a suitable and convenient method to quantitatively assess the morphology. Abstract A series of petroleum coke species obtained from commercial plants has been studied by polarized-light microscopy observation (PMO), scanning electron microscope (SEM), and Raman spectroscopy characterization (RS). The morphological characteristics of needle coke, shot coke, and transition coke differed apparently from each other. An explicitly close Growth/Sigmoidal relationship between parameters determined from polarized-light micrographs and Raman spectra was observed. The full width at half maxima (FWHM) of D 1350 was more appropriate than I D1350 / I G1580 for morphological correlation, and then establishing the criterion. It was shown that RS with proper spectra decomposition procedure could be a suitable and convenient method to quantitatively assess the morphology of petroleum cokes. [ABSTRACT FROM AUTHOR]

Hydrogen transfer property is of great importance in the carbonization of heavy oils. Thermal treatment under hydrogen was performed on a raw slurry oil (SO) from FCC process. The theoretical hydrogen-donating property of SO fractions before and after treatment was predicted by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. The hydrogen-transfer experiments using anthracene (ANT) and 9,10-dihydroanthracene (DHA) as chemical probes were carried out to determine the hydrogen transfer ability (HTA) of SO fractions, the effect of which was examined by subsequent carbonization experiments. Results show that the donatable hydrogen contents of SO fractions are increased after thermal treatment under hydrogen. A modified method for calculating the hydrogen-donating ability (HDA) of the fractions is proposed on the basis of the 1 H NMR data of the reacted mixtures derived from the hydrogen-donating experiments. The results calculated with this method are more accurate with inherent ANTs and DHAs considered. The HDA is found to be closely related to the composition of hydroaromatics in terms of the content and hydrogen-donating activity. The hydrogen-accepting ability (HAA) of the fractions is also calculated with similar method proposed accordingly, and thus the hydrogen-donating index that quantitatively describes the HTA is obtained. Thermal treatment under hydrogen improves the HTA of the fractions considering the increased HDA and decreased HAA after treatment, and also improves the morphology of derived semi-cokes as indicated by subsequent carbonization experiments. The correlation between the HTA of SO fractions and the morphology of derived semi-cokes reveals that the quality of derived cokes improves as the HTA of carbonization feedstocks improves, not necessarily in positive correlation with the HDA of SO fractions nor necessarily in negative correlation with the HAA of SO fractions. [ABSTRACT FROM AUTHOR]

The effectiveness of continuous synthesis of petroleum coke-based potassium ion battery anodes by chemical activation agent cycle was systematically studied. The potassium ions storage performance in the synthesized carbon anode was measured. High‑sulfur petroleum coke, as a natural sulfur-doped hard carbon skeleton, can provide an excellent active site for the storage of potassium ions. Ultrasonic intensification significantly reduces the elution time required for neutralization and eliminates the need for a forced increase in elution temperature and rate to improve elution efficiency. In the continuous synthesis process, the recycled chemical activation agent not only does not destroy the activation effect but also has stable activation performance and a good driving force for the growth of activated carbon quality (the specific surface area is 1000 ∼ m 2 g− 1 ). Moreover, the sulfur content of the prepared hard carbon anode gradually decreases, whereas its electrical conductivity gradually increases, resulting in an increase in its potassium ions storage capacity. The carbon anode prepared by chemical activation agent after four cycles has a high reversible capacity of 290 mAh g− 1 at 0.5 A g− 1 and excellent cycling stability (99.5% hold rate at 0.5 A g− 1 after 400 cycles). The galvanostatic intermittent titration technique results show that appropriate sulfur content and perfect carbon skeleton structure can promote potassium ions intercalation kinetics. In conclusion, the chemical activation agent cycling strategy can be used to achieve the continuous synthesis of petroleum coke-based potassium ion battery anode. [Display omitted] • The ultrasonication assisted successive synthesis of HSPC-based AC was researched. • The different post-treatment cost of AC was found. • Serial analysis was used to elucidate ultrasonication enhancement mechanism. • The recycle of K 2 CO 3 registered a stable activation performance with growth of AC quality. [ABSTRACT FROM AUTHOR]

With uncertain wind and PV power integrated into the grid, the difficulty of peak shaving is exacerbated. Therefore, the peak shaving operation of hydropower has become one of the most important problems in power system. In this paper, an optimal operation strategy of hydro-unit level coordinated peak shaving and economic operation in hydro-wind-PV hybrid system under uncertain conditions of wind and PV power is proposed. Firstly, the uncertainty of wind and PV power is described based on Latin hypercube sampling and scenario reduction methods. Secondly, a two-layer optimization model considering wind and PV uncertainty is established. And then, the synchronous peak shaving strategy and the improved lambda flow iteration strategy are proposed to solve the model. A case study is performed with the HWPHS in the Yarlung Zangbo River basin of China. The results show that (1) The residual load of power system fluctuates steadily under the condition of wind and PV uncertainty, and the peak shaving rate is 95.53%. (2) Compared with the DP algorithm, the proposed algorithm can increase the economic efficiency by 0.89% when solving the lower-layer model. (3) The V3 shaped mapping function proved to be superior to other functions. [ABSTRACT FROM AUTHOR]

[Display omitted] • PtPd/CN was fabricated for cyclohexane dehydrogenation at low temperatures. • Pt 0.75 Pd 0.25 /CN catalyst exhibited better catalytic activity than Pt/CN and Pd/CN. • The electronic coupling in PtPd alloy promotes catalytic performance. While Pt-based heterogeneous catalysts have been extensively studied for cyclohexane dehydrogenation, the reaction efficiency under low temperatures remains to be resolved. In this paper, ultrafine PtPd alloy nanoparticles homogeneously anchored on nitrogen-doped carbon were synthesized and applied for cyclohexane dehydrogenation. The experimental results indicate that the synergistic effect of Pt-Pd in PtPd/CN catalyst enhances the activity and durability of the catalyst in cyclohexane dehydrogenation compared with Pt/CN and Pd/CN catalysts. The as-prepared catalyst (labeled as Pt 0.75 Pd 0.25 /CN) exhibits an excellent catalytic performance with an initial TOF value of 90.07 mmol·g−1 metal ·min−1 and a 100% H 2 purity for cyclohexane dehydrogenation at 180 °C, exceeding reported values under comparable reaction conditions. Catalyst characterizations and DFT calculations reveal that the electronic coupling effect of Pd and Pt in PtPd/CN catalyst makes the d-band center of Pt active sites closer to the Fermi level, which promotes the specific adsorption/activation of cyclohexane on Pt active sites, thus improving the catalytic performance of cyclohexane dehydrogenation. Under this guidance, the synthesized PtRu/CN and PtIr/CN alloy catalysts exhibited similar enhanced activity in cyclohexane dehydrogenation. This work provides insights into the rational design of efficient and stable Pt-based bimetallic catalysts for cyclohexane dehydrogenation. [ABSTRACT FROM AUTHOR]

• The thermal reaction of residue and SARA fractions at 250–400 °C was studied. • Resins and asphaltenes produced coke at 250 °C with no coke induction period. • Asphaltenes are the sole fraction that generated reactive radicals at 250 °C. • Coking at high temperature is strongly correlated with the radical evolution. • Maltenes could suppress asphaltenes coking, serving as the immunity system. In this study, the coking propensity and reactive radical evolution of heavy residue and SARA fractions at 250–400 °C were studied to gain an insight into the coke induction process. The interactions among fractions for thermal coking were discussed. Results showed that residue started to form coke (i.e. toluene-insoluble at room temperature) at 350 °C for longer times while resins and asphaltenes have already extensively produced coke at 250 °C with no coke induction period. This indicates that the coke induction depends on the solubility gap of reactant and coke. The coking process can be fitted with the second-order and autocatalytic kinetics for residue while second-order kinetics for heavy fractions with initial coke precursor amount varying with temperature. Asphaltenes are the sole fraction that generated reactive radicals at 250 °C and responsible for the radicals of thermal residue. The explosion of reactive radicals began when the temperature exceeded 350 °C and became steady as the thermal reaction proceeded. The coke at low temperatures mainly originated from the molecules aggregation with faint radical emergence while that at high temperatures is strongly correlated with the radical evolution. The maltene subfractions could suppress the coking of asphaltenes possibly because of the physical solvation and chemical hydrogen donating behavior to cap reactive radicals. It can serve as the intrinsic immunity for coke inhibition of heavy residue during thermal partial upgrading. [ABSTRACT FROM AUTHOR]

In this study, catalyst particles (the main component is Al 2 O 3 –SiO 2 ) were removed from the fluid catalytic cracking slurry oil by adding a polyacrylamide flocculants (1200 μg/g) and a ammonium citrate aqueous solution weighting agent (10% by weight of the slurry oil) at 95 °C, and then settled for 18 h. The ash content which determined by the muffle stove was considered as a criteria for measuring the efficiency of sedimentation. The size and distribution of the catalyst particles, before and after sedimentation, were analyzed using a laser particle size analyzer and a light transmission microscope. The results showed that the removal efficiency could reach 95.12% when both the flocculants and weighting agent were added. However, either the flocculants or weighting agent applied individually could only obtain inferior removal efficiencies of 87.04% or 68.76%, respectively. It would be attributed to the synergistic effect between the two agents. Moreover, it was also found that the flocs were rapidly formed from original catalyst particles and the flocculants firstly. Then the weighting agent provided assistance for the sedimentation of the flocs, of which the process was identified as the control step. The sedimentation process established in the experiment might play a role in the industrial removal of catalyst particles from slurry oil in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • The olefin distributions of thermally cracked products derived from VR was investigated. • The effect of olefinic-bond-containing aromatics (OAH) on coke formation was revealed. • Evolution characteristics of OAH during thermal reaction was studied. • OAHs can form larger molecules via non-free radical reaction. The distributions of olefinic-bond-containing aromatic hydrocarbon (OAH) and the effect of OAH on coke formation during heavy oil thermal cracking have been rarely studied in the past. Here, the information of olefins in thermally cracked products derived from vacuum residue (VR) was investigated first, and then the effect of OAH on coke formation was elaborated by revealing the evolution characteristics of self/co-addition systems participated by representative OAH model compounds. The results found that OAHs were generated during VR thermal cracking, and they could participate in further reactions to promote coke formation. During thermal reaction, OAHs were more reactive for addition reactions than alkenes, and the reactivity of OAH increased roughly with the number of aromatic rings. Meanwhile, the higher concentration of OAH or the longer thermal reaction time or the higher thermal reaction temperature, the higher conversion of addition products, and the greater condensation degree of reaction products. OAHs participating in the larger structure molecule formation involves free radical addition reactions, which could occur between different OAHs as well as between OAHs and conventional aromatic molecules. More importantly, OAHs could form larger structure molecules by direct addition reaction of unsaturated double bond via non-free radical addition reaction, thus promoting fast coke formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • V, Ni, and Fe in wastewater were decontaminated and crystallized into nanoparticles. • The formed V 2 O 3 , NiO, and Fe 3 O 4 could catalyze both WGSR and PAHs hydrogenation. • The WGSR was coupled into PAHs hydrogenation by providing in-situ H 2. • Metals in wastewater and PAHs in fuel could be reduced simultaneously. The developing chemical demetallization technologies of petroleum emit thousands of tons of V, Ni, and Fe into water bodies annually for just one oil refinery. For this reason, a metal-containing wastewater (MCW) treatment and reutilization technique is highly demanded to be integrated into petroleum processing. This work introduced an in-situ decontamination of V, Ni, and Fe-containing wastewater from oil refineries into catalytically active particles for polycyclic aromatic hydrocarbons (PAHs) disposal. The water–gas shift reaction (WGSR) was coupled into the reaction system by providing the in-situ H 2. In one step, 98.7 wt% of soluble metal ions were precipitated into metal oxides, and 89.6 wt% of anthracene was hydrogenated. It took only 1 h for V, Ni, and Fe ions to crystallize into nanoparticles of V 2 O 3 , NiO, and Fe 3 O 4 , which could promote both the PAHs hydrogenation and the WGSR. The hydrogenation efficiency via in-situ H 2 was 48.7 % higher than that via ex-situ H 2. With the increase of PAHs aromatic ring number, the PAHs hydrogenation via in-situ H 2 was enhanced. Therefore, this method could simultaneously effectuate the separation of heavy me tals from MCW and the disposal of noxious PAHs in fuel oils. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of olefins on the coking propensity of residual oil (RO) was investigated. • The coking propensity of RO was higher than that of original VR. • The coking propensity linearly increased with the total olefin content of RO. • Olefinic-bond-containing Asp contributes the most to the increased coking propensity, followed by olefinic-bond-containing Re. Olefins, especially olefinic-bond-containing aromatics (OAH) may have a significant effect on the coking propensity of heavy residual oil (RO) derived from vacuum residue (VR) thermal cracking products in the further deep processing. However, this has been rarely studied in the past. In this work, the structure of RO (boiling point > 500 °C distillate) products and their SARA fractions derived from thermal cracking of VR under different conditions were systematically characterized by 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopy to investigate the occurrence pattern of olefins. The coking propensity of RO in the further processing was evaluated by thermal gravimetric (TG) and coking factor analysis, and the effect of different olefins on the coking propensity of RO in further processing was revealed. The results showed that the thermal cracking led to the occurrence of olefins, especially OAHs in resins (Re) and asphaltenes (Asp). The highest olefinic hydrogen contents of RO and its SARA fractions were detected at the thermal cracking condition of 415 °C for 40 min, which were 2.9 %, 4.0 %, 3.4 %, 2.8 %, and 2.4 %, respectively. Interestingly, RO obtained at the thermal cracking condition of 415 °C for 40 min also had the highest content of TG carbon residue (11.2 wt%) and the largest value of coking factor (5.33 %). Significantly, the TG carbon residue content and coking factor value of RO linearly increased with the total olefinic hydrogen content of RO, suggesting that the occurrence of olefins during thermal cracking significantly contributed to a greater coking propensity of RO in further deep processing. More importantly, an in-depth investigation by adding different olefin model compounds to the original VR thermal reaction system revealed that the olefinic-bond-containing aromatics in Asp may confer the greatest contribution to the increasing coking propensity of RO, followed by the olefinic-bond-containing aromatics in Re. [ABSTRACT FROM AUTHOR]

FCC decant oil was always used as the raw material for the preparation of high-value-added carbonaceous materials. There is little disagreement that the free radical mechanism induces thermal polymerization reactions between reactant molecules and intermediate species, which leads to the formation of carbonaceous mesophase in the early stage of carbonization. Olefinic hydrocarbons were recently found to be widely distributed in FCC decant oil in our previous research, and these chemically active compounds usually possess weak π-bonds in molecules and thus potentially form free radicals easily, which may impact the carbonization performance dramatically. This research investigated the effects of olefinic compounds on the preparation of needle coke from FCC decant oil, as well as the corresponding mechanism in depth combined with the evolution pattern of the intermediate species during liquid carbonization. ESR analyses were adopted to evaluate the variation of the concentration of stable free radicals. Stable free radical concentration varied greatly in diverse polymerizing systems along with the carbonization process. Olefin showed a significant effect on the stable free radical concentration during carbonization. The stable free radical concentration of the polymerizing system derived from FCC decant oil was 3.32 × 1020 spins/g when the reaction time was 4 h. But with 3 wt% addition of 2-vinylnaphthalene and squalene in FCC decant oil, the stable free radical concentration increased to 2.14 × 1021 spins/g and 1.33 × 1021 spins/g, respectively, with the same reaction time. Meanwhile, the olefins conjugated with aromatic rings shown more obvious effect on the generation of free radicals. Olefinic compounds can lead to a high generation rate of free radicals and significantly high stable free radical concentration in the polymerizing system which then promote the formation of disordered carbon materials. Besides, plenty of fine particles appeared between mesophase spheres with the addition of olefinic hydrocarbons, and then impeded the coalescence between mesophase spheres. Effect mechanism for olefin on the development of carbonaceous mesophase was proposed accordingly. In sum, the content of olefinic compounds in raw materials should be limited for reaching the requirements of the synthesis of carbon materials with superior structures, in which the content of olefinic compounds should be less than 1 wt% at least based on the research in this paper. [Display omitted] • Concentration of stable free radical varies greatly along with carbonization. • Effect of olefin on the free radical concentration is revealed for the first time. • Olefin shows great impacts on the intermediate species during carbonization. • Influence mechanism of olefin on carbonization process is proposed. • Olefin content in feedstock should be limited for high-value-added utilization. [ABSTRACT FROM AUTHOR]