Global warming and energy shortage is a worldwide problem. The use of solar energy photocatalytic reduction of carbon dioxide into high value-added carbon chemicals is expected to become an important way to solve the above problems. Therefore, it is crucial to develop efficient and low-cost photocatalytic materials. Among the known two-component catalysts, direct Z-scheme heterojunctions photocatalysts have attracted wide attention due to their lower rate of photo-generated electron-hole recombination, strong oxidizing and reducing capabilities, and higher photocatalytic reaction efficiency. The principle of photocatalytic reduction of carbon dioxide and the identification of direct Z-scheme heterojunctions (including photocatalytic reduction experiments, radical identification experiments, in situ X-ray photoelectron spectroscopy, metal loading, and theoretical calculations) are reviewed. The photocatalytic mechanism of direct Z-scheme heterojunctions is clarified. In addition, the current research status of common catalysts for oxidation or reduction in direct Z-heterostructure is summarized. Finally, the challenges and opportunities faced by the development of this field are summarized and prospects are given.

In order to capture carbon dioxide (CO₂) from the flue gas of a natural gas-fired power plant and to recover the cold energy of liquefied natural gas (LNG), a hierarchical process for recovering the cold energy of LNG is proposed. The process divides LNG into deep, medium, and shallow cold by temperature and matches each segment of cold energy separately to the circulating medium to recover LNG cold energy, water, and captured CO₂ while delivering electricity to the outside world. In the Organic Rankine Cycle (ORC), the heat source is flue gas and the cold source is LNG. The thermodynamic analysis of the system shows that the heat recovery efficiency, cold energy utilization, power generation efficiency, and exergy efficiency of the system are 41.55%, 14.34%, 10.80%, and 53.60%, respectively. The CO₂ capture and cold energy generation are 177.30 kg/t and 25.86 kWh/t, respectively. In addition, the LNG regasification pressure is investigated and the maximum CO₂ capture rate is achieved at a gasification pressure of 1.00 MPa. The higher exergy efficiency indicates the novelty of the hierarchical cold energy utilization process design and the suitability of the working fluid for use in ORC.

In order to solve the problems of intermittency and instability of renewable energy, based on the supercritical compressed carbon dioxide energy storage (SC-CCES) system, the thermodynamic performance of the system was analyzed by using CO₂-based binary mixture as the circulating working medium. The energy storage performance of different mixtures in different proportions and the influence of key parameters such as compressor inlet temperature, heat source flow rate and pressure drop of high pressure throttle valve on the system round-trip efficiency and energy storage density were studied. The results show that the round-trip efficiency of the supercritical CO₂ mixed working medium energy storage system increases with the increase of the mass fraction of krypton gas, and is higher than that of a single CO₂ working medium. With the increase of the mass fraction of isobutane, R32, R134a and propane, the energy storage density will gradually increase. The research results lay a theoretical foundation for the future application of CO₂ mixed working medium energy storage cycle project.

Capillary pumping and replenishment features on nanowire clusters surfaces with V-grooves were used to investigate thin liquid film evaporation on nanowire clusters surfaces with V-grooves by experimental observation and model analysis. The effects of surface structural parameters and the liquid level of grooves on the evaporation performance were investigated, and a thin liquid film evaporation model was established to solve the equations of liquid film profiles in nanowire clusters and V-grooves, and to analyze the heat transfer performance. The results show that the heat transfer coefficient of thin liquid film evaporation increases with the decrease of nanowire diameter and the increase of nanowire height, up to 369 kW/(m²·K). The liquid film in the cluster has an extremely high climbing speed driven by capillary force, so that the liquid film still evaporates at the top of the cluster under small liquid holding volume. The liquid film in V-grooves completely wets the trench and connects with the liquid film at the top of the clusters to replenish the liquid for the evaporation of the clusters, and the drop of the liquid level in grooves does not affect the evaporation in the top of clusters, which extends the length of the thin liquid film and decreases the thickness of the liquid film on the side wall of the groove to further strengthen the heat transfer. The macroscopic heat transfer coefficient of the liquid film in the nanowire clusters is significantly higher than that in the grooves, which proves the decisive role of the clusters in the overall evaporation, and elucidates the microscopic mechanism of the thin liquid film evaporation on nanowire clusters surfaces with V-grooves.

Heater surfaces made of different materials exhibit various thermal response characteristics during boiling process due to differences in thermal properties. To deeply investigate the effect of thermal properties on the interaction between the thermal response of the heater surface and the dynamic behavior of bubbles during single-bubble boiling process, based on the open source software OpenFOAM, a thermofluid coupling numerical model including heat transfer, phase change and flow is developed by analyzing the heat and mass transfer process within the microlayer. Firstly, single-bubble boiling simulations have been realized on different sized pores on copper, aluminum, and silicon surfaces. The results show that with the improvement of thermal conductivity, the superheat of the heater surface decreases and the waiting period of the bubble is shortened, while the effect of thermophysical properties on the waiting period of bubbles gradually decreases with the decrease of vaporization core size. In addition, for the copper surface coated with graphene, the graphene coating enhances the lateral diffusion of heat on the boiling surface. Due to the slow heat transfer rate from the substrate material, a significant amount of heat is carried away from the heating surface by liquid evaporation, this leads to a slower recovery of superheat at the vaporization core, resulting in lower surface superheat and longer waiting periods for bubbles.

The immersion liquid cooling technology based on boiling phenomenon is suitable for chip (server, data center, etc.) and motor cooling, which can realize the modularization, integration and miniaturization of cooling system and has broad application prospects. In the development of an immersion cooling system, it is usually hoped to minimize the volume of working fluid without affecting the performance of the system. Therefore, this study proposed a bubble pump technology to reduce the filling volume of the working fluid by circulating it in the cooling system, utilizing the two-phase rising flow induced by boiling bubbles as the driving force. In this study, Novec-7100 was selected as the working fluid and an experimental system with the ability to visualize the bubble behaviors was established, and the characteristics of vapor-liquid two-phase flow, the performance of vapor/liquid transportation, and the performance of heat transfer were examined. As a result, it was found that the best performance of the bubble pump can be achieved for the microchannel with the cross-section of 3 mm × 3 mm, within the range of conditions adopted in this study. This type of bubble pump can normally operate for the heat flux in the range of 0.89—9.68 W/m² when 120 mm of the channel is immersed in the working fluid.

Using computational fluid dynamics software and based on the Euler-Lagrange method, numerical simulations were conducted on the deposition characteristics of the bottom surface of an inlet pipe box of a waste heat boiler. The effects of different mass flow rates (0.002—0.010 kg·s^-1), inlet velocities (1.5—3.5 m·s^-1), and particle diameters (20—60\mathrm{\mu }\mathrm{m}) on the deposition characteristics of the bottom surface are studied in detail. The simulated gas-solid two-phase velocity matches well with experimental data, verifying the applicability of the model. The simulation results show that: (1) When the particle diameter remains unchanged, in order to improve the bottom surface deposition, the inlet velocity and particle mass flow rate should be reduced as much as possible. (2) When the particle mass flow rate remains constant, if the particle diameter is less than 40 \mathrm{\mu }\mathrm{m}, a smaller inlet velocity can effectively improve the bottom deposition situation; If the particle diameter is greater than 40 \mathrm{\mu }\mathrm{m}, increasing the inlet velocity can significantly improve the bottom deposition situation; If the particle diameter is 40 \mathrm{\mu }\mathrm{m}, the change in inlet velocity can hardly change the bottom deposition rate. (3) When the inlet velocity remains constant, in order to improve the bottom deposition situation, the particle diameter and particle mass flow rate should be minimized as much as possible.

To probe into the fragmentation laws of particle aggregate in the flow field of the classifier. Based on the soft sphere model, the fragmentation behavior of aggregate in turbo air classification flow field and the effects of single particle size, single particle number, and shape of aggregates on aggregate fragmentation are studied. The results show that: aggregates undergo deformation and then fragmentation under the action of drag force after entering the classification flow field. The smaller the single particles, the stronger the agglomerates they form. Spherical aggregates have the strongest aggregation, followed by cylindrical aggregates, and cubic aggregates have the weakest aggregation. The more single particles that make up the agglomerates, the longer it takes for them to completely disagglomerate in the classification flow field. When the agglomerates are large enough, they may not be completely disagglomerated and are collected as coarse powder, resulting in the“fishhook effect”. Thus, completely fragmentation of aggregates can be promoted by optimizing the flow field to retard aggregates settling or pre-dispersion treatment for the raw materials.

Combining the porous media foaming technology with the Venturi bubble generator, a porous media-Venturi bubble generator is developed. Using deionized water and air as the working material, the experimental study on visualization of gas production characteristics is carried out. Photographs to observe the bubble behavior in the region, analyze the porous media-Venturi bubble generator gas production law, discuss the influence of water flow and air flow law. The experimental results show that, compared with the traditional Venturi bubble generator, under the same inlet Reynolds number, the Sauter mean diameter of bubble produced by the porous media-Venturi bubble generator was reduced by 25.3%—47.4%, and the standard deviation was reduced in the range of 24.4%—62.2%, which indicates that the Sauter mean diameter of bubble produced by the improved bubble generator is smaller, and the particle size of bubbles is more uniform. The water flow rate increased from 5.01 m³/h to 14.98 m³/h, the Sauter mean diameter of bubble produced by the porous media-Venturi bubble generator decreased from 0.89 mm to 0.29 mm, and the standard deviation decreased from 0.32 mm to 0.085 mm; the gas flow rate increased from 0.30 L/min to 1.79 L/min, the Sauter mean diameter of bubble produced by the porous media-Venturi bubble generator increased from 0.33 mm to 0.48 mm, indicating that the Sauter mean diameter of bubbles produced by the bubble generator became smaller and the particle size distribution of bubbles was more uniform when the water flow rate was increased or the gas flow rate was decreased. The results provide an idea for the optimization of the Venturi bubble generator.

In order to reduce the mixing isolation zone, increase the chaotic mixing zone and enhance the fluid chaotic mixing process, based on the self-similarity of fractal theory, a stirring impeller with fractal-arranged perforated holes to enhance the fluid chaotic mixing behavior was proposed. The power consumption characteristics, velocity distribution, shear strain rate distribution, isolation zone structure and Poincare section during the fluid mixing process were investigated by using computational fluid dynamics (CFD) combined with experiments. The results showed that FAPT impeller could effectively reduce the power consumption and power number compared with RT at the same Reynolds number, and the power consumption and power number could be further decreased with the increase of fractal iteration number of perforated holes. Compared with RT system, the power number of FAPT-1 system was reduced by 6.57%—12.50%, the power number of FAPT-2 system was reduced by 10.95%—19.32%, and the power number of FAPT-3 system was reduced by 15.25%—24.66%. FAPT impeller could enhance the shear effect on the fluid, increase the shear strain rate of fluid, reduce the isolation zone, shorten the mixing time, and improve the fluid mixing efficiency compared with Rushton turbine under the same power consumption, and this effect was more obvious with the increase of fractal iteration number of perforated holes.

The rising behavior of particle-loaded bubbles was studied by high-speed camera technology. The particle adhesion rate was introduced to quantitatively characterize the amount of particle adhesion on bubbles, with polymethyl methacrylate (PMMA) particles used as the basic material for the particle bed layer. Changes in the bubble-particle adhesion rate were observed under different particle sizes and flow rates, and analyses were conducted on the bubble morphology, bubble size, and vertical ascending speed of particle-loaded bubbles. The ascending behavior characteristics of particle-loaded bubbles were revealed. The research results indicate that under conditions of a 300 μm particle size, an increase in flow rate reduces the amount of particles loaded on bubbles, resulting in a decrease in the particle adhesion rate. However, the impact of increased flow rate on the particle adhesion rate is effectively offset by reducing particle size. Under larger particle size conditions, higher particle adhesion rates stabilize bubble morphology, resulting in smaller overall bubble size and slower vertical ascending speed. The influence of flow rate on bubble morphology, size, and vertical ascending speed is weakened by decreasing particle size. Smaller particle sizes lead to an increased production of anisotropic bubbles with approximate particle adhesion rates.

Based on the traditional magnetization model, the van der Waals force model is added, and the finite volume method (FVM) and discrete element method (DEM) are used for numerical simulation. The gas-solid two-phase flow analysis is performed using the Fluent-EDEM dual platform coupling to study the effect of van der Waals force on the movement of nanoparticles under different magnetic field directions and different magnetic induction intensities. The results indicate that the impact of van der Waals forces between nanoparticles on particle movement in magnetic fluidized beds cannot be overlooked, and there exists a distinct inhibitory relationship between van der Waals forces and magnetization forces at low magnetic flux density. The stratification of nanoparticles becomes more pronounced at a magnetic field angle of 0°, and the stratification effect gradually diminishes with increasing field intensity. The van der Waals force also deflects the direction of particle motion to a certain extent. The introduction of van der Waals force model further broadens the application range of magnetization model and provides data support for studying the motion of nanoparticles in magnetic field.

A novel twisted tube coaxial heat exchanger was developed, and its heat transfer and flow characteristics were experimentally tested. Correlation formulas for Nusselt number (Nu) and friction factor (f ) criteria for the tube and shell passes were derived. The experimental results indicate that the total heat transfer coefficient and flow resistance increase with higher flow velocities. Within the test range of 0.1—1.5 m/s, the total heat transfer coefficient increased by approximately 34%, while the flow resistance increased from 37 Pa to 6033 Pa, representing a nearly 120-fold increase. The shell flow resistance increased from 361 Pa to 130761 Pa. For Reynolds numbers between 1000 and 10000, the performance evaluation factor (\eta) of the twisted tube coaxial heat exchanger exceeds 1, and reaches a maximum of 2.3. However, for Reynolds numbers between 10000 and 30000, \eta is less than 1. The overall comprehensive performance of the twisted tube coaxial heat exchanger is the best within a tube flow rate range of 0.1—0.5 m/s and a shell flow rate range of 0.1—0.4 m/s, indicating that it is suitable for small refrigeration and air conditioning equipment as well as application scenarios with low Reynolds numbers.

Flow pattern identification of gas-liquid two-phase flow plays an important role in the improvement of production capacity and efficiency of petrochemical industry. The nonlinear and non-stationary characteristics of conductance fluctuation signal lead to the difficulty of feature extraction and affect the accuracy of flow pattern identification of gas-liquid two-phase flow. Aiming at this problem, a new flow pattern identification method which combines multi-feature extraction with a grey wolf algorithm optimized support vector machine (GWO-SVM) is proposed in this work. In the research, statistical analysis and approximate entropy analysis are used to extract statistical features and normalized approximate entropy features of the conductance fluctuation signals. And the two different kinds of features are combined to form a dataset. Then, to improve the accuracy of flow pattern identification, grey wolf optimization (GWO) algorithm is used to optimize the support vector machine (SVM) model. The gas-liquid two-phase flow pattern recognition experiment showed that the proposed method has higher recognition accuracy than the SVM, PSO-SVM and GA-SVM methods, and the average flow pattern recognition rate reached 98.45%.

The deep hydrogenation of phenanthrene into perhydrophenanthrene, a primary component of aviation fuel, has been acknowledged as a viable strategy for the clean exploitation of coal tar. To solve the problem of sulfur poisoning in the deep hydrogenation process on Ni-based catalysts, Ni/Al₂O₃ catalysts with sufficient hydrogenation centers was coupled with desulphurisation agent ZnO in four different ways. The effect of the distance between Ni/Al₂O₃ and ZnO on hydrogenation performance of sulfur-containing phenanthrene was systematically investigated. X-Ray diffraction and X-ray photoelectron spectroscopy were used to characterize the structure of the catalyst. The results show that the closest filling method Ⅳ exhibits the best catalytic performance. After 10 h, the conversion of phenanthrene and the desulfurization of dibenzothiophene can still be maintained at 100.0%, and the selectivity of the target product perhydrophenanthrene is 98.0%. The characterization results showed that the close distance promoted the reaction of the intermediate sulfur species from dibenzothiophene with ZnO to form ZnS. This catalyst enables both deep hydrogenation and hydrodesulfurization performance by modulating the interactions between the two sites, which in turn augments the stability of Ni/Al₂O₃ during the deep hydrogenation process of sulfur-containing phenanthrene.

High-pressure tubular reactors are crucial equipment for the production of LDPE (low-density polyethylene) and EVA (ethylene-vinyl acetate copolymer) and other products. Due to the harsh conditions of high-pressure polymerization reactions, the design of high-pressure tubular reactors must not only meet the process requirements of polymerization but also the mechanical strength and fatigue life requirements of the equipment. Taking the high-pressure LDPE tubular reactor as the research object, a two-step optimization strategy for the structure of tubular reactors is proposed. Firstly, the required pipe diameter ratio of the reactor is determined according to the ultra-high pressure vessel standards, and the influence of the initiator formulation on the heating rate of the tubular reactor is calculated based on the detailed model of the tubular reactor. Secondly, the total annual cost per unit conversion is used as the objective function, and genetic algorithms are employed to optimize the structural parameters such as the pipe diameter and length of the partition. The structure optimization method proposed in this paper is highly accurate and will provide theoretical guidance for the optimal design and technical transformation of high-pressure LDPE tubular reactors.

The interfacial sites between Pt and promoters are highly conducive to the selective oxidation of glycerol to 1,3-dihydroxyacetone (DHA). In this study, two Pt-based catalysts with different Pt-Bi interfacial structures, Pt/Bi₂O₃-CNTs and PtBi/CNTs, were prepared by using atomic layer deposition and impregnation-reduction method, respectively. The selective oxidation of glycerol on the two catalysts was investigated through a combination of experiments and density functional theory (DFT) calculations. Characterization results show that there is a relatively uniform Pt-Bi₂O₃ interface structure in the Pt/Bi₂O₃-CNTs catalyst, while the PtBi/CNTs catalyst forms a Pt₁Bi₁ intermetallic compound. Both catalysts promote the preferential oxidation of the secondary hydroxyl group in glycerol. Comparatively, the Pt/Bi₂O₃-CNTs catalyst demonstrates superior glycerol oxidation activity due to its smaller particle size and higher Pt⁰ 4f binding energy, whereas the PtBi/CNTs catalyst facilitates the deep oxidation of DHA. Furthermore, DFT calculations reveal that the rate-determining step for the oxidation of the secondary hydroxyl group of glycerol to DHA on both catalysts is C—H bond cleavage, with a relatively lower energy barrier observed on the Pt/Bi₂O₃-CNTs catalyst, resulting in higher reaction activity. On the surface of the PtBi/CNTs catalyst, DHA exhibits greater adsorption affinity, rendering it more susceptible to deep oxidation. The insights provided here could serve as a guide for the design and optimization of Pt-based catalysts for the selective oxidation of glycerol to DHA.

A series of nano-sized ZSM-5 agglomerates were prepared by adding different ratios of cetyltrimethylammonium bromide (CTAB) as a crystal growth inhibitor during the synthesis of crystal seeding method. The pore structure and acid properties of the samples are characterized by XRD, SEM, ICP, Ar adsorption-desorption, NH₃-TPD and other analytical methods, and the effects of CTAB on the physical and chemical properties of ZSM-5 molecular sieves were elaborated. The addition of appropriate amount of CTAB inhibited the further growth of crystals while promoting the crystallization of ZSM-5 molecular sieves, so that the primary nano-crystals agglomerated to increase the specific surface area, while promoting the construction of micropores and increasing the acid sites. The catalytic performance of this group of molecular sieve samples was evaluated for the methanol to propylene (MTP) reaction at high air velocity using a fixed-bed reactor. The results showed that sample Z5-2 (with a CTAB/SiO₂ molar ratio of 0.02 in the synthesized initial material) had suitable pore structure and acid volume, and exhibited good catalytic performance with propylene selectivity at 47.6%.

Polyethylene hydrogenolysis can produce a variety of hydrogen hydride compounds, the product distribution is very wide, and the product selective regulation is challenging. A series of Ru/CeO₂ catalysts with different Ru particle sizes were prepared by regulating Ru loading. It was observed that the product distribution of polyethylene hydrogenolysis closely correlated with the coordination environments of metal Ru as determined by multiple techniques including TEM, in situ DRIFTS and model calculations. Characterizations and model calculations revealed that Ru nanoparticles with different particle sizes exhibited different metal dispersion, geometric structures and coordination environments. The C₂—C₄₀ alkanes selectivity of 92% was achieved by using Ru particle sizes with mean diameter of 0.85 nm where the edge/corner sites with low-coordination are dominant. The C₂—C₄₀ alkanes selectivity of 8% and the methane selectivity of 92% was obtained by using the Ru particle sizes with mean diameter of 2.75 nm where the terrace sites with highly coordinated platform sites are dominate. Combined with truncated hexagonal bipyramid model and CO-DRIFTS experiment, the selectivity of products over Ru/CeO₂ catalysts was correlated with the interaction between intermediates of polyethylene hydrogenolysis and the surface of Ru nanoparticles. Furthermore, the relation between reaction pathways in polyethylene hydrogenolysis and coordination environments of metal Ru was proposed.

Azo lake pigments are one of the important organic pigment varieties and are widely used in various industrial fields. The continuous-flow synthesis of Pigment Red 57 using the microreactor technology is of great significance for the innovation of azo lake pigments production technology. First, a microreactor system was built, and the reaction conditions of diazotization, coupling and laking process were optimized in the system. Under the optimal reaction conditions, the yield of diazonium salt was greater than 99%, the yield of pigment red was greater than 99%, and the solid recovery after laking was close to 100%. Finally, different alkali metal salts or alkaline earth metal solutions were used for laking process to achieve the regulation of chromatic light. Among them, the chromatic light after Sr²⁺ and Ba²⁺ laking was brighter, and the red and yellow hues were intense. The chromatic light after Zn²⁺, Mg²⁺, Mn²⁺ laking was dark, and the green and blue hues were intense.

Ethylene production is a key indicator reflecting the development level of a country's petrochemical industry. A particle-resolved fixed-bed reactor model for selective acetylene hydrogenation process has been established. The impact of cylindrical particle packing structure on the transport processes has been analyzed and the influence of operational conditions on the reaction performance has been explored. The results showed that the pressure drop in the catalyst bed mainly happened in the entrance section of the reactor, where the reaction rate of acetylene hydrogenation is the highest. However, in the latter half of the bed, the catalyst particles are not fully utilized, and there is a significant radial temperature gradient within the reactor. In terms of operational conditions, increasing the inlet pressure and decreasing the gas velocity both favor the improvement of acetylene conversion rate, but at the same time, they would reduce the selectivity of ethylene, where the selectivity of ethylene is more sensitive to pressure, and the conversion of acetylene is more sensitive to gas velocity. The increase in reaction temperature and hydrogen-to-acetylene ratio both help to promote the acetylene conversion to ethylene, but it can lead to the enrichment of ethylene on the exterior surface of the catalyst particles, which when diffusing further into the interior zone, can be over-hydrogenated to ethane, thus reducing the selectivity of ethylene.

This investigation examines the influence of the Al₂O₃ support pore structure on the activity and selectivity of FeMo/Al₂O₃ pre-hydrodesulfurization (HDS) catalysts. A series of FeMo/Al₂O₃ catalysts with different pore structures were synthesized by the impregnation method. The catalytic HDS performance was evaluated by using COS, CS₂, C₄H₄S and C₂H₄ as the probe molecules in a micro-fixed bed reactor. The physico-chemical properties of γ-Al₂O₃ supports and the corresponding FeMo catalysts were characterized by using methods such as N₂-physisorption, infrared carbon-sulfur analysis instrument, XRD, NH₃-TPD, H₂-TPR, XPS, Raman and HRTEM. The results of the research indicate that the Al₂O₃ carrier hole structure has a significant effect on the catalyst activity of MoS₂ phase, which affects the hydrogen desulfurization activity and selectivity. Among them, the carrier of the larger pore diameter is more conducive to the effective conversion of COS and CS₂, while the carrier of the smaller pore diameter is more inclined to promote the conversion of C₄H₄S and C₂H₄. Furthermore, catalysts with larger pore sizes not only showed reduced tendencies for carbon accumulation but also enhanced the dispersion of Mo species, effectively modulating the growth dimensions and layer counts of MoS₂ crystallites. This led to exceptional HDS activity performance for COS and CS₂, offering novel avenues for the engineering and development of highly effective HDS catalysts.

The Ru/WC-C catalyst was prepared by dispersing Ru on the WC-C support, and its catalytic performance in hydrogen generation from ammonia borane hydrolysis was tested. The phase structure, morphology and surface element state of the catalyst were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The results showed that Ru nanoparticles were evenly scattered on the surface and surroundings of WC, and the electronic synergy effect between the Ru and WC promoted the hydrogenation of ammonia and hydrolysis of ammonia. Under the condition of 298 K and alkaline solution environment, the hydrolysis performance of ammonia borane was related to the Ru content. With the increase of Ru content, the hydrogen production time was shortened. The completed hydrogen production time of 2%Ru/WC-C catalyst with a Ru mass fraction of 2% was 3.5 min, and its hydrogen generation rate value was 573.0 min^-1 with activation energy of 45.3 kJ·mol^-1. Moreover, its hydrogen generation rate value in the neutral aqueous solution was still as high as 136.2 min^-1. The application of WC-C carrier can effectively promote the activation of water molecules during the reaction, and then improve the catalytic performance of Ru catalyst. This study provides a new insight for the development of low-cost and efficient catalyst for hydrogen production from ammonia borane hydrolysis.

Extraction technology can be considered as an important supplement to the hydrodesulfurization and denitrification process to separate aromatic sulfur and nitrogen components in oil products. This study investigates the separation of benzothiophene and quinoline from fuel oils using ionic liquids (IL) as extractive solvent at both molecular and experimental scales. COSMO-RS model identified 1-ethyl-3-methylimidazolium dicyandiamide ([EMIM][DCA]) as the optimal IL extractant from 37 IL candidates. The extraction performance of [EMIM][DCA] for separating benzothiophene and quinoline was demonstrated by liquid-liquid equilibrium experiments. Regeneration experiment indicates that the selected IL maintained stable extraction efficiency in 5 cycles. The separation mechanism of the extraction process was uncovered. Molecular dynamic simulations and quantum chemical calculations show that π-π interactions and C—H…N hydrogen bonding between the IL and benzothiophene/quinoline are the primary forces driving the efficient separation. The conclusions present here offer theoretical guidance for designing new and effective extractants.

In this paper, a new type of waterflow classifier device that can adjust the impeller speed and the upward water velocity without chemicals was adopted, which could avoid the large consumption of reagents and low efficiency of sorting during the traditional flotation. Characteristics of the product obtained by separating the residual carbon from gasification fine slag by using three methods: direct water flow classification (DWFC), screening and then step-by-step classification (SWFC), and screening a wider particle size (>0.074 mm) and then waterflow classification were examined. The results demonstrated that the floating slag yield increases with the increase of impeller speed and water velocity, while the loss on ignition (LOI) of the floating slag increased first and then decreased. Compared with DWFC, SWFC can avoid the problem of difficult separation of the fine particles (<0.074 mm), thus can significantly improve the efficiency of the carbon separation. By using wide particle size (>0.074 mm) screening and optimizing the water flow classification conditions, the scum extraction loss on ignition can reach 84.44%, the combustible body recovery rate can reach 65.85%, and the comprehensive efficiency can reach 43.39%. This research confirmed that by pre-screening and then waterflow classification, the residual carbon in the coal gasification slag could be efficiently recovered.

In order to expand and explore the potential applications and mechanism analysis of ionic liquids in the field of volatile organic compounds (VOCs) absorption, diethyl ether, acetone and dichloromethane were used as representatives of VOCs, through the quantum chemistry calculation module DMol3 in Materials Studio software, at the DNP/GGA/PW91 level. VOCs absorption sites of single-molecule and multi-molecules, hydrogen bonds, absorption energies (E_abs) and charge of three quaternary phosphine ionic liquids (PILs) were simulated and calculated, which are tributyl(propyl)phosphonium tetrafluoroborate ([P₄₄₄₃][BF₄]), tributyl(propyl)phosphonium bis(trifluoromethyl-sulfonyl)imide ([P₄₄₄₃][Tf₂N]), and tributyl(propyl)phosphonium tetrafluoroacetate ([P₄₄₄₃][CF₃COO]). Accompanied by charge transfer, hydrogen bonds are formed between PILs and three types of VOCs. The dominant role of PILs in absorbing different types of VOCs is different. In the process of absorbing VOCs, anions and cations have different effects on the absorption. The results showed that the anions of PILs have little effect on the absorption of ether and acetone. The hydrogen bonds formed by the anions of PILs and α-H of ether are weak. The absorption sites of PILs for acetone are mainly the cation α-H or β-H and carbonyl O, and anions play a major role in the absorption of methylene chloride. The main role of PILs and methylene chloride is the hydrogen bond formed by the basic active site of the anion and the H of methylene chloride. The E_abs of [CF₃COO]^- for methylene chloride are obviously prominent. [P₄₄₄₃]⁺ ion pairs generally have three similar absorption active sites, and the space for accommodating VOCs molecules is mainly provided by cations. Analysis of the double ion pair spatial structure of ionic liquids shows that PILs composed of weakly basic and larger anions are more likely to expose their absorption sites. Experimental studies further show that compared with imidazole ionic liquids, PILs exhibit excellent VOCs absorption capabilities.

Gas-liquid microsulfonation technology is a new sulfonation method with great development potential because of its safety, efficiency, and low cost. However, due to the high viscosity of the sulfonation reaction system, the pressure drop is huge when flowing in small-sized channels, which significantly increases the energy consumption of the microreactor. Therefore, realizing the optimal regulation between the efficient heat and mass transfer performance of the microreactor and the high-pressure drop of the gas-liquid sulfonation reaction system is vital for the practical promotion and application of the gas-liquid microsulfonation technology. In this paper, the pressure drop characteristics of the gas-liquid microsulfonation reaction process and the role mechanisms of the influencing factors were investigated through experimental tests, and the prediction models of the gas-liquid sulfonation yield and energy consumption of four different structures of microreactors were established based on the method of magnitude analysis. In order to achieve high yield and low energy consumption, the improved NSGA-Ⅱ algorithm was used to optimize the critical process parameters affecting the yield of sulfonation products and energy consumption of the reaction process. The C-ES (cross-shaped mixing zone + through-channel reaction zone with expansion unit) type microreactor achieved 89.771% yield and only 1.609 kW/t energy consumption at a gas velocity of 6.422 m/s, a liquid velocity of 0.0147 m/s, and a reaction time of 91.464 min, which demonstrated that the C-ES microreactor has high effective mass transfer efficiency and can significantly enhance the mass transfer between gas and liquid phases at low energy consumption. It proves that the C-ES microreactor has high effective mass transfer efficiency and can enhance the gas-liquid two-phase mass transfer with low energy consumption. The above study provides a theoretical basis for the design of microreactor structure and optimization of operating conditions aiming at high yield and low energy consumption.

Using supercritical carbon dioxide as the lubrication, a theoretical model of foil cylindrical air film seal lubrication is established considering the high-speed fluid effects such as turbulence, blockage and inertia. The study investigates the variations in the seal end flow field and foil deformation under different combinations of high-speed fluid effects, revealing the operational mechanism of high-speed, high-pressure supercritical carbon dioxide compliant foil cylindrical gas film seal. Furthermore, the impact of operating conditions and structural parameters on sealing performance is analyzed, providing an optimal range for structural parameters. The results show that turbulent effects have a significant impact on the flow field and sealing performance of the supercritical carbon dioxide compliant foil cylindrical gas film seal lubrication interface, while blockage and inertia effects are relatively minor. There are interactions among various fluid effects: turbulent effects reduce the pressure at the blockage exit boundary, while inertia effects increase it. Moreover, under turbulent conditions, inertia effects have a more significant impact on the float force. Optimal sealing performance is achieved when the length-to-diameter ratio is between 2.0—2.5 and the flexibility coefficient is between 0.001—0.003.

The development of new absorbents is an important research direction for CO₂ capture. Deep eutectic solvent (DES) is a mixture of two or more compounds formed by hydrogen bonding and is regarded as a potential green solvent. The DESs were selected as the CO₂ absorbents, namely choline chloride/urea (ChCl/urea)(molar ratio 1∶2), choline chloride/glycerol (ChCl/Gly)(1∶2), and choline chloride/ethylene glycol (ChCl/EG)(1∶2). The thermodynamic models of DES were established based on Aspen Plus by regressing the vapor-liquid equilibrium parameters and the other thermophysical parameters. The COAMO-SAC was used to predict the solubility of N₂ and O₂ in DES, and a CO₂ capture process was built. The effects of absorption pressure, absorption temperature, the number of stages, and CO₂ concentration were studied. The results show that the regeneration energy consumption of ChCl/urea(1∶2), ChCl/Gly(1∶2) and ChCl/EG(1∶2) process can be reduced by 35.17%, 35.00% and 15.28% compared with the traditional amine process at 90% of CO₂ removal efficiency and 90% of CO₂ purity. Considering the regeneration energy consumption, solvent demand and solvent loss of DES, ChCl/Gly(1∶2) has the most promising application prospect. The study can provide reference for the feasibility of CO₂ capture industry by DES.

The Ca(OH)₂/CaO thermochemical heat storage system has the advantages of high energy density, low cost, and inter-temporal storage. A more in-depth revelation of the multi-physics field coupling mechanism of the reaction will help to improve the performance of the system. In this work, for the exothermic process of Ca(OH)₂/CaO system, a biaxial stirred reactor was proposed and its heat and mass transfer and chemical reaction processes were numerically investigated. The feasibility of the biaxial stirred reactor was analyzed, and the exothermic characteristics of the system were discussed. In addition, the effects of the reaction conditions, such as heat transfer coefficient, stirring speed, initial and inlet temperatures, steam pressure and filling height, on the exothermic process were investigated in detail by analyzing the variation of the conversion, the exothermic power and the bed temperature, so as to provide directions for the determination of suitable reaction conditions. The results show that the biaxial stirred reactor with stable flow and temperature fields improves the heat and mass transfer performance of the exothermic reaction. The conversion of the exothermic process of the system during 1200 s is 0.49, the peak and the stable exothermic power can reach 5.4 kW and 3 kW, respectively. The reaction temperature zone of the system can be controlled by adjusting the steam pressure, whereas a lower initial and inlet temperature accelerates the reaction and reduces the additional preheat of the system. The heat exchange capacity of the reactor will significantly affect the exothermic process, especially under the reaction conditions of high speed and high filling height. In practical applications, the needs should be considered to match the appropriate heat exchange device. The model and results in this work could help optimize the stirred reactors and provide theoretical guidance for future large-scale heat storage applications.

Carbothermal reduction is an effective means of reducing and detoxifying hexavalent chromium compounds in waste incineration fly ash, but carbothermal reduction conditions and changes in the composition of the fly ash can affect the speciation transformation of chromium. Bamboo charcoal (BC) and powered active carbon (PAC) were used to react with Na₂CrO₄ to explore the process of carbothermal reduction on the morphological transformation of \mathrm{C}\mathrm{r}(\mathrm{Ⅵ}), and the effects of four oxides on the morphological transformation of \mathrm{C}\mathrm{r}(\mathrm{Ⅵ}) in the carbothermal reaction were analyzed. The experimental results showed that Na₂CrO₄ was reduced to NaCrO₂ below 1000℃ and converted to Cr₃C₂ above 1000℃. In the presence of oxides, when the temperature was higher than 1000℃, Fe₂O₃ reacted with the chromium reduced by BC to form FeCr₂O₄. When the CaO content was high, it was converted into CaCr₂O₄, if an excessive amount of BC was added, it was still dominated by Cr₃C₂. When trace amounts of BC were added to calcium-sprayed fly ash, the reduced chromium reacted with CaO to form CaCr₂O₄; when excessive amounts of BC were added, Cr(Ⅵ) was reduced to form Cr₃C₂.

Associated gas booster reinjection flooding is an important measure to achieve carbon emission reduction in oil and gas exploitation, but the associated gas is a CO₂/CH₄ mixture, the composition fluctuates violently, and the properties of CO₂ near the critical point are extremely unstable, which poses a severe challenge to the stability of the gas injection compressor. In order to clarify the trans-critical pressurization characteristics of CO₂/CH₄ mixture, the PR equation of the physical properties of the mixture was constructed, the physical properties and phase changes of the mixture were calculated, and the safe pressurization path was clarified. Based on this, the theoretical trans-critical pressurization thermodynamic model of CO₂/CH₄ mixture was constructed, and the p-V diagram, valve movement law and indication power of the mixture trans-critical pressurization process were obtained, and the influence mechanism of component concentration on physical properties and thermal performance of the compressor was compared and analyzed. The results show that with the increase of CO₂ concentration, the saturated gas phase moves to the high temperature region, the critical temperature increases, the inlet and exhaust pressure loss increases during the pressurization process, and the compressor power consumption decreases by 22.93% when the CO₂ concentration increases from 20% to 100%. The relevant research results can provide a theoretical basis for the design and reliable operation of the trans-critical supercharging compressor of CO₂/CH₄ mixture.

Gas diffusion layer is a key component of a proton exchange membrane fuel cell. It can support and protect the proton exchange membrane and catalyst layer, and provide the channels for electrons conduction and gas transfer. As the main parameter of the diffusion layer, the porosity affects the characteristics of the diffusion layer and ultimately affects the battery performance. In this paper, a 3D agglomerate model is established to study the influence of constant value and stepwise non-uniform distribution on cell performance, and also explore the optimal porosity at different voltages. The results show that increasing porosity can improve cell performance in concentration polarization region, but reduce the performance in ohmic region. Porosity increasing along flow direction is beneficial for cell performance, but the change magnitude should be smaller. Porosity increasing from under rib to under gas channel can enhance cell performance. The optimal porosity is various at different voltages and reduces with voltage increasing, and the current density can be increases by 5.28% at 0.2 V.

Stefan's models for thermal decomposition of natural gas hydrate with density jump is established by using the principle of mass conservation. The general form of Rankine-Hugoniot jump relation was derive in detail, and the Stefan coupling condition in cubic form with respect to the velocity of interface was obtained, but the cubic term could be ignored within the errors of engineering requirements. It is the introduction of velocity terms in the Stefan model that makes it difficult to obtain an exact solution to the model. The mass as a space variable was introduced by the Quilghini transformation, the velocity term was vanished, and become the classical Stefan-like's models. Followed by the inverse Quilghini transformation, the accurate analytical solutions of the Stefan's models with density jump could be successfully gained. Through Matlab programming, a concrete example was taken, laws on the solutions of transcendental equation, temperature distribution and dissociation interface were studied, the influences of injection temperature and density jump on solutions of transcendental equation, penetration depth, penetration time and hydrate displacement were probed. The errors caused by density jump were within the permissible ranges of engineering.

K₂S₂O₈ was used as an oxidant to treat the cathode powder of spent lithium iron phosphate (LiFePO₄) batteries by three methods: oxidation leaching, mechanical activation combined oxidation leaching, and mechanical solid-phase oxidation combined water leaching. The results showed that under the optimal conditions of the three methods, the Li leaching rate of the oxidation leaching method was 89.03%(mass), and the Li leaching rate of the mechanical activation combined oxidation leaching method was 92.36%(mass). The mechanical solid-phase oxidation combined with water leaching method had the best effect, with a Li leaching rate of 98.26%(mass). At this point, Fe compounds can also be completely separated from Li, improving selectivity. The leached lithium ions were extracted and recovered in the form of Li₃PO₄ precipitation by adding K₃PO₄. After detection by inductively coupled plasma mass spectrometry, the purity can reach 98.67%(mass). The leaching mechanism was analyzed by using X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that in the process of mechanochemical solid-phase oxidation, mechanical force not only induced a decrease in particle size, but also acted as a driving force for the oxidation reaction, causing Li⁺ to migrate out and Fe(Ⅱ) to be oxidized to Fe(Ⅲ), providing good conditions for the subsequent water leaching process and achieving selective separation of Li and Fe.

The polyamide reverse osmosis (RO) membrane was modified with the quorum sensing inhibitor methyl anthranilate (MA), which was dissolved in an ethanol/aqueous solution. As an activating solvent, ethanol can dissolve polyamide oligomers and swell separation layer, thus improve membrane permeability. After solvent activation and grafting MA, the hydrophilicity of the modified membrane surface increased, the roughness decreased, the water flux was higher than that of the original membrane, and the rejection was maintained. Besides, the modified membrane had good performance stability and acidic-alkaline resistance stability. Escherichia coli was used as simulated bacteria in water to investigate anti-biofouling performance of the membranes. After 5 d of contact with the concentration of 10⁷ CFU/ml bacteria, the area on the surface of the membrane surface prepared by 10 g/L MA was only 0.27% of the original membrane. When bacterial suspension concentration reached 10⁹ CFU/ml, biofilm areas on the membranes surface prepared with MA of 5 g/L and 10 g/L were reduced to 0.79% and 0.66% compared to original membrane, respectively. The results demonstrated that introducing MA can inhibit bacterial proliferation. In addition, after soaking in Songhua River water containing nutrient solution for 2 d and 5 d, the rejection decline rates of the modified membrane were significantly lower than those of original membrane.

In wastewater treatment, the advanced oxidation process based on peroxymonosulfate (PMS) is considered to be one of the most efficient and green methods for degrading organic pollutants. Among the methods of activating PMS, transition metal-supported catalysts have attracted much attention due to the low dissolution of metal ions, but they face the problem of low degradation activity, which is caused by the easy aggregation of metal species. In this work, Co was loaded on reduced graphene oxide (rGO), and Co highly dispersed QSCo-rGO and Co agglomerated AGCo-rGO were synthesized by a simple method. XRD, HRTEM and element mapping studies showed that Co in QSCo-rGO was highly dispersed without metal agglomeration. The Co in AGCo-rGO was aggregated in the form of CoO nanoparticles. In the reaction of activating PMS to degrade phenol, QSCo-rGO could complete 100% degradation efficiency within 30 min, while AGCo-rGO required up to 90 min. In addition, QSCo-rGO exhibited good reusability and versatility. The mechanism study indicated that Co in QSCo-rGO catalyst was highly dispersed, which exposed more active sites, and it generated non-free radical ¹O₂ by activating PMS to degrade phenol with high activity. This work provides a new idea for designing advanced oxidation catalysts with enhanced degradation activity.

Permonosulfate (PMS) was activated by copper-iron Prussian blue derivatives (Cu _n Fe₁-PBAs) to degrade rhodamine B (RhB). The effects of the molar ratio of iron to copper, the amount of catalyst, the molar ratio of PMS to RhB, initial pH and common ions in water on RhB degradation were investigated. The results showed that Cu₂Fe₁-PBAs could effectively activate PMS to degrade RhB. RhB degradation was most favorable under alkaline conditions when RhB concentration was 20 mg/L, Cu₂Fe₁-PBAs dosage was 0.6 g/L, and PMS concentration was 0.513 g/L. \mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}, \mathrm{H}\mathrm{C}{\mathrm{O}}_{\mathrm{3}}^{-} and Cl^- promoted the degradation of RhB, while \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-} inhibited the degradation of RhB. Sulfate radical (\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{-}·), hydroxyl radical (·OH), singlet oxygen (¹O₂) and superoxide radical (·{\mathrm{O}}_{\mathrm{2}}^{-}) all participated in the RhB degradation of Cu₂Fe₁-PBAs activated PMS.

The effect of dispersant on the nanoparticle (NP) dispersion in liquid is significantly affected by solution environment. This article uses coarse-grained molecular dynamics simulation methods to study the effects of three solution environmental factors, including pH, temperature and dispersant concentration, on the dispersion stability of liquid nanoparticle systems containing dispersants. It was found that the dispersion effect of dispersant on NPs mainly depends on two aspects, i.e., the adsorptions of dispersant molecules on the NP surface and the aggregations between the dispersant molecules. Through the synergistic action of these two aspects, the dispersant can achieve effective dispersion of NPs. In terms of the mechanisms affecting the NPs dispersion, dispersant concentration affects the relative quantity of dispersant molecules adsorbed on the NP surface and connected with each other forming aggregates; different pH induces the dispersant molecules hydrolyze and modify themselves from electroneutral into electriferous structure in different degree; and temperature affects the stability of connections between dispersant molecules, as well as between dispersant molecule and other individuals in liquid. The above results provide theoretical basis for the control on the dispersion stability of NP liquid system.

To address the wide applicability of the route of preparing fluorine-free foam extinguishing agent with low-carbon alcohol modulated hydrocarbon and silicone surfactants, as well as the limitation of evaluating the fire extinguishing effect in small-scale fire extinguishing experiments, a new silicone surfactant SILOK and two types of hydrocarbon surfactants CHX-3 and SDS were selected as the key basic components to carry out the design of the compounding scheme of the fluorine-free foam extinguishing agent, the foam basic performance test, real fire extinguishing experiment and molecular dynamics simulation. The test showed that the fluorine-free foam extinguishing agents of CHX-3/SILOK/isobutanol and SDS/SILOK/isobutanol with five compounding systems had good foam base performance, and the surface tension of the design scheme was in the range of 20.3—22.7 mN/m, the stabilizing coefficient of foam was in the range of 0.9617—0.9762, and the 25% drainage time was in the range of 203—238 s. But relatively speaking, the Case5 formulation which the mass fraction of CHX-3/SILOK/isobutanol is 0.48%/0.1%/0.03%, respectively, had better foam base properties, low surface tension, good foaming and stabilizing properties. True fire extinguishing experiment has proved that in the Case5 scheme of the CHX-3/SILOK/isobutanol system, 90% flame control time is only 42 s, the fire extinguishing time is the shortest, only 49 s, and the average fire cooling rate is the largest, reaching 7.59℃/s. Through molecular dynamics simulation, it was found that the hydrogen bond types, bond lengths and bond angles of the two types of complex systems were different due to the difference of hydrocarbon surfactants. The essential law of the effects of CHX-3 and SDS on foam stability and surface tension was clarified. The research results can provide data support and theoretical support for the development, application and popularization of fluorine-free foam extinguishing agent.