The rapid development of global industrialization and population growth have led to increasing consumption of fossil fuels, resulting in increasing carbon dioxide (CO₂) emissions year by year, triggering global climate issues. Presently, the alkanolamine absorption method is the most widely used for CO₂ capture in industries, mainly using aqueous solutions as monoethanolamine and methyl diethanolamine as absorbent, which results in large solvent loss and high energy consumption for regeneration. The development of new absorbent with high efficiency and low energy consumption is the key to achieve large-scale CO₂ capture. Ionic liquids have the characteristics of great gas affinity, low vapor pressures and tunable structures properties. Phase-change ionic liquid systems are considered as the new generation solvents for CO₂ capture with low energy consumption. During CO₂ absorption, homogeneous ionic liquid-based solvents can undergo phase transition into liquid-liquid or liquid-solid immiscible systems. For regeneration, only the CO₂-riched phase needs to be heated, which reduces the regeneration volume of absorbent and energy consumption. This review summarized the progresses of the phase-change ionic liquid systems for CO₂ capture in recent five years, different liquid-liquid and liquid-solid phase-change behaviors of phase-change ionic liquid systems were discussed. The development trends of CO₂ capture in phase-change ionic liquid systems were also prospected.

Polymer gas separation membranes have the advantages of low price and easy processing, but there are problems such as gas separation performance is difficult to meet the industrial requirements, and the aging resistance and structural stability are poor. Carbon molecular sieve (CMS) membranes have high mechanical properties, high heat and chemical corrosion resistance, suitable gas transport paths, heteroatomic structure with good affinity for gas molecules and pore size structure with strong molecular discrimination, exhibiting excellent gas separation performance, thus receiving wide attention and being considered as a promising gas separation membrane. The 6FDA-based polyimide not only has larger rigidity and restricted conformation, but also has larger free volume, adjustable molecular structure, good pore formation and high carbon residue, and the gas separation performance of as-prepared CMS membranes are better than that prepared by other precursors, which is favored by the academic and industrial sectors. This paper introduces the structural design principle of CMS membranes precursors, carbonization mechanism during the pyrolysis processes and the control of microstructure, the influence of carbon structure on gas separation performance, the gas transport mechanism in the membrane, and the application of CMS membranes prepared by 6FDA-based polyimide in gas separation. In combination with our own scientific research practice, the strategy of the structure design and preparation of CMS membranes prepared by 6FDA-based polyimide is proposed to provide new ideas for the future application of CMS membranes in gas separation.

With the rapid growth of the lithium-ion batteries (LIBs) market, exploring effective strategies to recycle retired LIBs has become an urgent issue. In the future, resource-based recycling will receive wide attention. Resource-based recycling can not only solve the problem of shortage of valuable metals such as lithium, nickel, cobalt and manganese, but also solve the hazards caused by the accumulation of used batteries. However, the safety of transportation, storage and metal enrichment processes cannot be guaranteed. In this paper, we review the progress of the recycling process of retired LIBs, and focus on the safety risk analysis of the whole recycling process, including transportation, storage, pretreatment and metal enrichment. By analyzing and organizing the safety risks in the recycling process of retired LIBs, we hope to provide guidance for the subsequent battery recycling programs of domestic and foreign enterprises.

As one of the most widely used catalysts, the ZSM-5 molecular sieve has always been the focus of scholars’ research. Due to its better diffusion performance along the b-axis straight channels compared to that along the a-axis and c-axis the zigzag channels, the control of their length plays an important role in improving the catalytic properties of molecular sieves. The main methods for controlling the anisotropic growth of ZSM-5 molecular sieves are reviewed, including structure-oriented methods and growth modification methods. The application of short b-axis ZSM-5 molecular sieves in catalytic fields such as MTP, MTH, and MTG is analyzed in detail. It is also pointed out that lamellar molecular sieves prepared with specific quaternary ammonium salts as structural directing agents have a uniform and good self-pillared structure and intercrystalline mesopores. Due to the high difficulty in preparing structural directing agents, it is more economical and environmentally friendly to partially replace quaternary ammonium salts with growth modifiers. The synthesis of specific growth modifiers is low in difficulty and cost, and the prepared molecular sieves have dispersed or agglomerated lamellar structures. The development of new processes to improve intercrystalline mesopores will enable them to have better diffusivity. The in-depth study of the precise regulation of the thickness and acidity of lamellar molecular sieves, the synthesis mechanism, and the influence of anisotropic length on catalytic performance to ensure efficient preparation of molecular sieves that take into account conversion, selectivity, and stability is of great significance to the development of short b-axis molecular sieves.

Cold plate is the core component of indirect liquid cooling system of electronic equipment. Adding spoiler columns to the internal flow channel of cold plate can improve the heat transfer capacity of cold plate. In the design of cold plate spoiler column, it is necessary to consider both reducing the heat source temperature and reducing the pressure loss of fluid flowing through the flow passage. Combined with heat source temperature, fluid pressure drops, and power source energy consumption, the heat transfer performance of cold plate with inner flow channels containing rhombus, cylinder and droplet turbulence was studied. The results show that the heat transfer performance of the cold plate with the droplet column structure is the best, and the heat transfer performance of the cold plate is the best when the ratio of droplet column length to width is 2.5∶1. The heat transfer performance of the cold plate can be further improved by reducing the size of the droplet column and increasing the number and density of the droplet column. In the experiments of this study, the heat transfer performance of droplet turbulence cold plate improves about 60％ compared with none turbulence cold plate.

The laminar and turbulent flow fields in a rotating membrane filter was investigated based on the computational fluid dynamics method. The porous media model was applied to describe the effect of the membrane permeability on the flow behavior, and validation experiments were performed to determine the membrane resistance correction coefficient and to verify model reliability. On this basis, fluid velocity and pressure distributions in the filter were numerically analyzed, and effects of rotational speed of the membrane on the transmembrane pressure and shear stress over the membrane surface were explored. The results show that the variation of dimensionless angular velocity of the fluid along radial direction over membrane surface exhibits a tendency that it almost keeps constant in the middle region, decreases gradually near the rotation axis, and increases slightly near the edge of the membrane, and that the flow state has a significant influence on the dimensionless angular velocity in the non-viscous core of the interstitial fluid above and below the membrane. It is also found that the transmembrane pressure tends to decrease along the radial direction, while it decreases with the increasing rotational speed of the membrane under the same flow state. Moreover, the shear stress increases linearly along the radial direction at the same rotational speed of the membrane, and increasing the rotational speed of the membrane remarkably increases the shear stress.

TiCl₄ oxidation reactor is the key equipment in the chloride process of TiO₂, while the scarring inside the reactor significantly affects its long-period and consistent operation. In this study, the scarring reason in the industrial reactor was firstly investigated by composition analysis, and then, by the CFD simulation of the internal flow and wall temperature distribution, which is employed in the ANSYS-Fluent software package under the circumstance of actual operating conditions. The simulation results show that the reactor wall temperature, internal flow field and other factors have a very important influence on the scarring of the reactor. The wall temperature in the hot-oxygen zone should be higher than 770℃ and that in the TiCl₄ feeding ring should be higher than 178℃, respectively, for preventing the additives of KCl and AlCl₃ depositing on the inner wall of the reactor. In order to avoid the newly generated TiO₂ to aggregate on the inner wall of the reaction zone, vortexes should be eliminated or reduced for the newly generated TiO₂ with high-activity to timely pass through the reaction zone.

Two kinds of anisotropic and isotropic porous media microfluidic chips with transverse and longitudinal throat width ratios (w_h∶w_z) of 1.48∶1 and 1∶1 were designed. Taking CO₂ as the gas and dimethyl silicone oil as the liquid, the effect of the structure of porous media on the growth and coalescence of bubbles under the condition of elevated temperature was systematically studied by using visualization experiments. The results show that the mass transfer growth caused by temperature rise was the driving force for bubbles to break through the throat. The growth direction of a single bubble in porous media depends on the threshold pressure, and bubbles tend to break through the throat with lower threshold pressure. As the temperature increases, the speed of air bubbles invading and breaking through the throat increases. In anisotropic porous media, bubbles tend to coalesce when they grew laterally. However, in isotropic porous media, bubbles are more likely to coalesce longitudinally. The initial distribution of multiple bubbles in anisotropic porous media can significantly affect the growth and coalescence of bubbles. However, in isotropic porous media, this effect is weaker. Anisotropic porous media is easier to realize the control of multiple bubbles in practical engineering applications.

Considering the difficulty of tilted falling of wet particles due to their poor flowability, a visualized tilt-fall experimental setup with mechanical vibration coupled with auxiliary fluidized gas was established, the effects of liquid saturation S, surface tension σ and tilt angle δ on the mass flow rate of three types of wet Geldart-D particles (plastic beads, glass beads and zirconia beads) were investigated, and three auxiliary dropping methods including individual mechanical vibration, individual auxiliary fluidized gas and vibration coupled with auxiliary fluidized gas were compared and evaluated. The research results show that, affected by the liquid bridge force, the mass flow rate q_m of the wet granule blanking process was reduced by more than 60% compared with that of the dry granule. The mass flow rate q_m of wet particles during tilt-fall increased with an increase of vibration intensity Γ and auxiliary fluidized gas velocity u_f. The effect of vibration intensity Γ on heavy particles such as glass beads and zirconia beads was comparatively considerable, and the influence of the auxiliary fluidized gas velocity u_f on the light particles, e.g., the plastic beads was more obvious. The auxiliary drop method of vibration coupled with auxiliary gas brings about higher wet particle drop mass flow rate under the same energy consumption, which is considered as the more energy-efficient method compared with other methods.

Ultrafine particles tend to agglomerate due to adhesion, which limits the preparation of ultrafine particles with small size and narrow distribution range through pneumatic classification. Studying the mechanism of agglomeration disaggregation can provide a theoretical basis for proposing measures to disaggregate. In this paper, application programming interface (API) of EDEM is used to generate the aggregates in the particle factory, and the numerical simulation of the movement of the aggregates and their disaggregation process near the guide vanes in the annular region of a turbo air classifier is carried out in FLUENT-EDEM coupling. The influence of different inlet air velocity on the aggregates is studied and the mechanism of disaggregation of aggregates near the guide vane in the annular zone is revealed. The results show that disaggregation of the aggregates near the guide vanes in the flow field is caused by the collisions between the aggregates and the wall of guide vanes, but not the shearing force of the flow field. When the rotating velocity of the rotor cage is 1200 r·min^-1 and the inlet air velocity is 6, 12, 18, and 24 m·s^-1, respectively, the proportion of single particles increases from 71.7% to 88.39% and the proportion of the aggregates decreases from 24.8% to 10.51% with the increase of inlet air velocity, the proportion of aggregates after partial disaggregation does not exceed 4%, indicating that the increase of inlet air velocity will improve the dispersion of powder near the guide vanes in the turbo air classifier. The introduction of dimensionless parameter—relative collision number verifies this conclusion.

The absorption of carbon dioxide by monoethanolamine (MEA) solution is widely used in carbon capture, utilization and storage technology, but the regeneration of MEA absorbing rich liquid requires high energy consumption. It has been reported that solid packing with catalytic properties can strengthen CO₂ desorption, however, the principle of solid action has not been clearly demonstrated. In this work, in order to investigate the effects of the particle packing, the effect of different solid particles (HZSM-5 with Si/Al ratio of 25, 50, 80 and activated carbon) on the regeneration process was compared, and it was showed that the surface acid sites on HZSM-5 zeolite promoted desorption in transit period by the adsorption of amine, and the maximum effect was 15.75%. The promotion was in the order of HZSM-5-25>HZSM-5-50>HZSM-5-80>AC>Blank. However, the solid particles could not be served as a catalyst due to limited adsorption capacity of the acid sites, it did not show significant promotion influence on the desorption in the stable continuously operation. During the constant desorption period, the promotion effect was only 1.61%—2.67%. Compared the acidic particles with the non-acidic AC particle, heterogeneous bubble nucleation was suggested to be a reason to promote the desorption. A hydrophobic surface may be the efficient packing material in industrial device to enhance gas-liquid separation. Furthermore, the effect of heating rate was investigated, and the results showed that heat flux is a much more important factor compared with the influences of catalysis and nucleation.

The pressure drop characteristics of subcooled water flow boiling in a mini-tube (1 mm) were experimentally investigated. The experimental parameters were as follows: heat flux 4.0—5.6 MW/m², pressure 3.0—5.0 MPa, mass flow rate 2000—4200 kg/(m²‧s), and inlet thermodynamic quality -0.50—-0.10. The effects of mass flow rate, pressure, heat flux and other parameters on the subcooling boiling resistance were obtained, and the prediction method was focused on. Comparison of the experimental data with typical pressure drop correlations indicates that the accuracy of the prediction for most pressure drop correlations is not sufficient due to special factors such as high heat flux and micro-channels. In order to predict the pressure drop of subcooled boiling of high heat flux more accurately, the extreme learning machine model optimized by genetic algorithm (GA-ELM) is established based on LeakyReLU function. The prediction accuracy of GA-ELM is better than the traditional correlations (the average absolute error is 2.0%), with well generalization ability. This study will support design optimization of micro/mini-scale flow heat transfer systems.

A novel copper-water flat heat pipe with porous metal-foam wicks has been conducted to study its heat transfer characteristics working in high heat flux and anti-gravity conditions. The effects of inclination angle, filling ratio and heat loads on the heat transfer characteristic of flat heat pipe, including its thermal response performance and thermal resistance, were investigated experimentally. The results showed that the flat heat pipe has a favorable thermal response performance. It can reach a stable state within 60 s. The thermal resistance of flat heat pipe decreases first and then increases with increase of filling ratio, and flat heat pipe with a filling ratio of 20% has the best performance. Inclination angle has a significant effect on thermal performance. Under the premise that the maximum temperature is within 90℃, flat heat pipe can dissipate 300 W with a thermal resistance of 0.0109 K/W. Besides, compared with the heat pipes reported in the literatures, this flat heat pipe not only obtains a lower thermal resistance, but also achieves effective heat conduction with higher heat flux. These results are of great significance to the design of advanced flat heat pipes.

Vanadium phosphorus oxide (VPO) catalysts doped with different transition metals were prepared by impregnation method, and their catalytic performance for cyclohexane oxidation by NO₂ to adipic acid were tested. The XRD, XPS, H₂-TPR and UV-Vis DRS were used to investigate the effect of transition metal doping on the valence structure of vanadium in VPO catalysts and the catalytic performance for oxidation of cyclohexane. The results showed that the introduction of transition metals could change the phase structure ratio of β-VOPO₄ and (VO)₂P₂O₇ in VPO samples, thus changing the ratio of V⁵⁺ and V⁴⁺. In addition, the valence structure of vanadium in VPO catalysts played an important effect in the oxidation of cyclohexane to adipic acid by NO₂. The catalytic performance of M/AlVPO catalyst containing both V⁵⁺ and V⁴⁺ was significantly higher than that of the pure V⁵⁺ β-VOPO₄ and pure V⁴⁺ (VO)₂P₂O₇ catalysts. Among them, when Cu/AlVPO with V⁴⁺/V⁵⁺ of 0.52 was used as the catalyst, the conversion rate of cyclohexane was 65.4%, and the selectivity of adipic acid was 84.8% when Ni/AlVPO with V⁴⁺/V⁵⁺ of 0.66 was used as the catalyst.

In order to strengthen the further study of micrystalline magnesite, the microcrystalline MgO obtained from calcined microcrystalline magnesite and the light burned MgO from a factory in Liaoning are used as raw materials for steaming ammonia, precipitating magnesium and calcinating to obtain MgO, and conduct hydration experiment. The effect of MgO activity on ammonia evaporation kinetics was investigated by water method, and the effects of reaction temperature and solid-liquid ratio on particle size and hydration rate of products were investigated, the morphologies of products with different solid-liquid ratios were investigated, and hydration curves were analyzed to determine the hydration reaction control types of different magnesium sources. The results show that the evaporation of ammonia in both of them is controlled by diffusion. Under the conditions of 100℃ and 9 h, when the solid-liquid ratio is 1/5, the microcrystalline MgO hydration product has a complete hexagonal sheet structure, while the sheet structure of the lightly burned MgO hydration product is different in size and irregular. Both hydration reactions belong to the internal diffusion chemical reaction control type. This study provides a new idea for the utilization and development of micrystalline magnesite.

In order to promote the rapid degradation of 2,4,6-trichlorophenol (2,4,6-TCP) and rapid removal of chloride ions in wastewater, a coupling system of photocatalysis and ion exchange adsorption was constructed in this study. The system consists of ruthenium (Ru), molybdenum (Mo) bimetallic doped monoclinic BiVO₄ coated photocatalytic quartz optical hollow fibers and ZnAL-LDH-NO₃ coated quartz optical fiber cloth. It is found that RuO₂/Mo-BiVO₄ photocatalyst has a porous and irregular polyhedron structure and small catalyst particle size, which helps to increase the specific surface area of the photocatalyst, promote photoelectric conversion and electron transfer, and Ru and Mo doping can effectively suppress photogenerated electron hole recombination, promoting the generation of oxidation active species (·OH and ·{\mathrm{O}}_{\mathrm{2}}^{-}), and improving the photocatalytic activity of BiVO₄. RuO₂/Mo-BiVO₄ coated photocatalysis hollow fibers has a removal rate of 62.4% for 200 ml, 80 mg/L 2,4,6-TCP in 6 h, 1.56 times that of BiVO₄ coated photocatalysis hollow fibers. At pH 6.2 and temperature of 35℃, the removal rate of 2,4,6-TCP in 6 h of RuO₂/Mo-BiVO₄ coated photocatalysis hollow fibers alone has increased to 74.2%, COD removal rate has reached 43.1%, and dechlorination rate has reached 40.3% (the concentration of chloride ions in the liquid phase has reached 443.2 μmol/L). The removal rates of 2,4,6-TCP, COD and chloride ions in the coupling system of photocatalysis and ion exchange adsorption reached 91.1%, 53.8% and 98.1% respectively in 6 h.

Microporous polymer membranes resistant to various organic solvents have gradually attracted attention in the field of organic nanofiltration. Herein, we report a covalent triazine framework membrane (CTF-BP) synthesized by a super acid-catalyzed organo-sol-gel reaction of commercially available aromatic nitrile monomer. This membrane exhibits good mechanical strength and is dimensionally stable in organic solvents, such as methanol, n-hexane, etc. Size sieving by the robust micropores (<1.0 nm) confers the membrane with a cut-off molecular weight as low as 550. The hydrogen interaction between triazine rings and the hydroxyl groups facilitates the transport of methanol, the flux of which reaches up to 1.10 L/(m²·h·bar), a value much higher than that of the less viscous n-hexane [0.23 L/(m²·h·bar)]. To demonstrate the practical applicability, this membrane is utilized to separate n-hexane containing low concentration of methanol solution [5% (mass) methanol], and a maximum separation factor of 1485 and a methanol flux of 3.21 kg/(m²·h) are obtained. These results demonstrate the great potential of the CTF-BP membranes in the recovery of methanol from its mixture with n-hexane via organic solvent nanofiltration (OSN).

In view of the difficulty of recovering 1,2-butylene oxide (BO) contained in tail gas in ethylbenzene hydroperoxide 1,2-butylene oxide (EBHP) plant, a novel absorption process for BO recovery with extraction solvent and extractive distillation (as desorption column) was proposed in this work, in that the reaction of both BO non-catalyzed hydrolysis reaction was considered. Meanwhile, the separation efficiency affected from solvent was characterized and solved based on the characteristics of liquid-liquid split for 1,2-butylene glycol (12BDO) and extraction solvent mixture at certain condition. The simulation and design optimization for the full process using Aspen Plus package with NRTL thermodynamic model were carried out. The influence of the main technological parameters, such as solvent ratio, the number of theoretical plates and the feed temperature of solvent was discussed. The results show that the new process has a recovery rate of 99.99% (mass) for butylene oxide, which has practical application value for the production capacity improvement of butylene oxide industrial equipment, energy saving and consumption reduction, and volatile organic compounds (VOCs) treatment.

Smooth operation is an important guarantee for refining-chemical enterprises to operate in inherent safety mode, produce economic benefits, realize potential and increase efficiency. However, due to the variety of crude oil supply and product demand, it has become common for refining-chemical production units to operate in multiple operation modes, and scheduling adjustments are becoming more and more frequent. Existing research methods do not take into account the impact of scheduling adjustments on smooth operation, such as multi-mode switching, and may even cause the scheduling operation scheme to be infeasible in practice. Therefore, this paper proposes a novel scheduling optimization model for refining-chemical production, which considers the smoothness of scheduling operation, to solve the problem that conventional scheduling optimization models tend to cause production to fluctuate and eventually lead to infeasible scheduling solutions. This model adopts a discrete-time representation, in which the smoothness is indicated by a combination of the switches between operating modes and fluctuations in the processing rate of the device, and introduces the minimizing production cost as the objective. To verify the effectiveness of the proposed model in solving real industrial problems, the JuMP package of Julia is used to call the Gurobi solver to simulate and solve typical cases. The case simulation results validate the correctness and implementability of the proposed model. Compared to the conventional scheduling optimization, the smoothness of scheduling operation characterized by process dynamics is improved by over 10%.

Due to the existence of closed-loop feedback system, not all faults will lead to quality deterioration. Quality variables are usually difficult to obtain or have a certain delay. The traditional unsupervised methods cannot judge the impact of faults on quality while detecting whether the process is normal or not. Canonical correlation analysis (CCA), a classical supervised method that can consider the relationship between input and output, has been used for quality-related fault detection. However, process data has problems such as high dimensionality and nonlinearity. The complexity of the system makes CCA more challenging to capture hidden features. This paper proposes a variational automatic encoder-orthogonal canonical correlation analysis (VAE-OCCA) method. First, unsupervised adaptive learning is performed on the input data using a variational automatic encoder to achieve feature extraction for high-dimensional nonlinear process variables. Then, the input-output relationship is considered based on the canonical correlation analysis method, and the obtained correlation coefficient matrix is used to perform singular value decomposition to establish quality-related and quality-independent monitoring statistics. Finally, the effectiveness and superiority of the method proposed in this paper are demonstrated through industrial case tests.

In the process of chemical production, due to the danger of materials and the complexity of the process, serious accidents occur frequently. It is necessary to reveal risk evolution mechanism to ensure the safe and stable operation of chemical processes, as well as to inhibit the spread, diffusion, or even evolution of secondary and derivative disasters. However, many traditional methods heavily rely on expert experience or prior information, which will cause the inaccuracy of risk assessment results. Although the community structure in complex network can be regarded as a highly abstract of risk evolution path, the existing algorithms cannot consider both of the rationality and accuracy division results. Therefore, a deep mining method of risk evolution path is proposed for chemical processes based on the DSAE-Louvain community structure. First, multi-source process data should be processed to establish a risk evolution network, and the Dijkstra and hop-count algorithms are further applied to obtain a similarity matrix. Then, the deep sparse autoencoder (DSAE) and Louvain algorithm are combined to divide the community structure using sparse analysis. Finally, the risk weak nodes and critical evolution paths in whole chemical processes are deeply mined according to the ranking of node importance. To illustrate its validity, the Tennessee Eastman (TE) process is selected as a test case. The results show that the proposed DSAE-Louvain method are more refined and high-efficiency in the community structure division by comparing with the GN algorithm, Louvain algorithm, and DSAE-GN method. Particularly, the mined risk evolution paths are more in accord with actual production processes.

The interaction between micro-oil droplets and solid surfaces in multiphase dispersion systems affects the productivity of many industrial processes such as oil-water separation, wastewater treatment and anti-oil-fouling. Investigating the mechanism of micromechanical interactions between oil droplets and surfaces of different properties in aqueous solutions is of substantial significance. However, it is still challenging to directly measure the interaction forces between micron-sized droplets and surfaces. In the present work, microscopic forces between micron-sized n-tetradecane oil droplets and hydroxylated or aminated modified silica surfaces in aqueous solutions were measured by using atomic force microscope (AFM) droplet probe techniques. The effects including interaction velocity, surface potential, ionic strength, pH and various surfactants on the interaction between oil droplets and surfaces in aqueous solutions were systematically investigated. The results showed that the hydroxylated silica surface was strongly negatively charged, while the surface electronegativity was weakened after the (3-aminopropyl)triethoxysilane (APTES) amination modification. At weak surface electronegativity, high ionic strength and acidic conditions, oil droplets in the dispersed phase are tended to attach to the surface under attractive forces such as van der Waals (VDW) due to the suppression of double electric layer (EDL) repulsion. The hydrodynamic force between the oil droplets and the surface enhances with the increase of the interaction velocity. The anionic surfactant sodium dodecyl sulfate (SDS) enhances the negative potential at the oil-water interface, allowing it to be more efficient than the cationic surfactant cetyltrimethylammonium bromide (CTAB) in maintaining the stability between the oil droplets and the silica surface. Meanwhile, the steric repulsion generated by the blocked polymer Pluronic F68 can effectively inhibit the attachment between oil droplets and surfaces in aqueous solutions. The research results help to further reveal the interaction mechanism between the oil droplet and the surface.

How to achieve both low oil leakage at low-speed condition and low gas consumption, high stability at high speed condition is the key problem in the design of the oil-gas seal used in vehicle turbocharger. Taking the oil-gas seals with pump-out spiral groove, splayed compound groove and Rayleigh compound groove as the research object, the two-phase Reynolds model derived from the continuity of oil and gas phase is used to solve the flow field distribution of the three different types oil-gas seals numerically, and the gas film thickness and medium leakage of the oil-gas seals under different working conditions are measured based on a special-designed test platform. The leakage characteristics and film-forming characteristics of the three different oil-gas seals in a wide speed range are compared, and the influence of key structural parameters, including groove depth, spiral angle and pump-out groove length ratio, on the leakage and film-forming characteristics of the splayed compound groove oil-gas seal is emphatically analyzed. The results show that the pump-out spiral groove can be selected as the optimal scheme when oil-gas seal operates under low-speed condition because of its minimum oil leakage, and the splayed compound groove seal can be regarded as the optimal one in the high speed condition because of its significantly lower gas consumption and larger gas film stiffness. But it depends on the reasonable design of its groove depth, helix angle and pump out groove length ratio. Under certain working condition and structural parameters, the compound groove face seal is expected to form an obvious oil-gas interface on the seal face in the radial direction, so as to achieve near zero leakage for both oil and gas.

Biomass-derived long-chain oxygenated fuels have good soot emission reduction properties and are promising diesel additives. In this work, the effects of 25% tripropylene glycol methyl ether (TPGME) and 25% polyoxymethylene dimethyl ether (PODE) additions on the soot precursor formation characteristics in n-heptane counterflow diffusion flames were experimentally and numerically analysed. The mole fractions of C₁—C₄ hydrocarbons in counterflow diffusion flames were measured by gas chromatography (GC). The experiments showed that the additions of TPGME and PODE suppressed the formation of ethylene and acetylene. The numerical simulations were performed through a reaction kinetic mechanism combined with the decoupling strategy, which could well capture the experimental observations. The simulations showed that the temperature differences in the key combustion zone were not more than 50 K, indicating that the oxygenated additives had little effects on the flame temperature. The dilution effect and thermal effect reduced the concentration of acetylene and ethylene, while chemical effect was beneficial to the formation of acetylene and ethylene. The rate of production (ROP) and reaction pathway analyses illustrated that unsaturated hydrocarbons were mainly generated via hydrogen abstraction and β-scission of n-heptane, and neither of the two additives had a remarkable impact on the pathways. Due to the presence of oxygen atoms, the carbon atoms on TPGME and PODE molecules trended to be converted into aldehydes and carbon monoxide (CO) instead of unsaturated hydrocarbons. Ultimately, the dilution effect and thermal effect played dominant roles in reducing the soot precursor emissions of n-heptane flame.

Ultrasonic degassing technology has practical or potential application value in chemical industry, metallurgy, environment, and geothermal energy utilization. However, there are few reports on ultrasonic degassing in air-water system. Therefore, this paper carried out the experimental study of ultrasonic degassing in the air-water system. The actual effect of ultrasonic on gas removal was studied under different operating parameters, such as ultrasonic electric power and frequency. At the same time, ultrasonic technology and vacuum degassing technology were combined to explore the degassing effect. The results show that the degassing effect decreases with the increase of ultrasonic frequency under the experimental conditions. The degassing effect increases with the increase of ultrasonic electric power. Compared with vacuum degassing alone, ultrasonic degassing combined with vacuum degassing can significantly improve the degassing effect. Under flow conditions, the degassing effect decreases with the increase of flow rate. The acoustic cavitation phenomenon in ultrasonic process was studied by KI experiment and visualization method. The results can provide basic guidance for the industrial application of ultrasonic degassing.

To recognize the synergistic inhibition of ionic liquids, the effects of N-butyl-N-methylpyrrolidine tetrafluoroborate ([BMP][BF₄]), two kinetic inhibitors (KHIs) (poly(N-vinylpyrrolidone) (PVP) and poly(N-vinylcaprolactam) (PVCap) ) and binary mixtures of KHI with [BMP][BF₄] on the hydrate formation process from methane/ethane/propane ternary mixture were investigated by using the isothermal isochoric method. By analyzing the time-dependent variation of pressure and gas phase composition, it was found that synthesized natural gas hydrate grew in a two-step way. At a high subcooling degree (>10℃) and stirring rate (1000 r/min), those tested additives failed when used alone, while an enhanced inhibition performance of PVCap was observed with the assistance of [BMP][BF₄]. Both powder X-ray diffraction and laser Raman spectroscopy test results show that the hydrate samples formed in all systems have sⅠ and sⅡ structures at the same time. The addition of inhibitors mainly affects the relative content of the two crystal structures and the cage occupancy of each guest molecule. Finally, a synergistic inhibition mechanism was proposed.

In order to explore the optimal solid-liquid separation method and process parameters, six air pollution control (APC) residues from waste incinerators were washed with water at a liquid to solid ratio of 3 L·kg^-1. Three methods of solid-liquid separation were adopted for the APC residues suspension, i.e., gravity sedimentation, centrifugal sedimentation and suction filtration. Their effects were evaluated based on the turbidity and total solids (TS) concentration of the supernatant/filtrate, the moisture content and capillary suction time of the mud cake. The results showed that gravity sedimentation was suitable for separating the APC residues with concentrated particle size distribution, and the best settling time should be set at the inflection point of the gravity sedimentation curve (20—70 min). The optimal centrifugal sedimentation parameters were 3000 r·min^-1, and 5 min. Suction filtration had the best effect on reducing supernatant/filtrate turbidity and mud cake moisture content, and was suitable for separating the APC residues with a wide range of particle size distribution. The results of this study can provide a theoretical basis for the engineering application of solid-liquid separation of washed APC residues, and the appropriate solid-liquid separation method can be selected according to the particle size distribution of APC residues, treatment capacity and site requirements.

In this work, the influence of the single cell number on output performance, cell uniformity and thermal management of high temperature polymer electrolyte membrane fuel cells stack (HT-PEMFCs stack) was investigated by combining numerical simulation and experimental method. The numerical simulation results show that when the number of single cell of the stack increases from 10 to 60, the average single cell voltage decreases slightly from 0.6414 V to 0.6404 V, and the voltage range between single cells increases from 1.8 mV to 6.5 mV. The average working temperature between single cells increases from 431.01 K to 433.90 K, and the range of the working temperature of each single cell increases from 6.95 K to 10.22 K. The numerical simulation results indicate that with the increase of the number of single cells in the stack, the average single cell voltage of the stack has a slight downward trend, and the voltage range between the single cells has increased, the voltage consistency between the single cells has decreased. Furthermore, the temperature difference between the single cells has increased, the uniformity of the average temperature of the single cell itself has also decreased, and the difficulty of the thermal management of the stack has increased. Under the guidance of the simulation results, HT-PEMFCs stacks with 30, 60, and 120 single cells were assembled and evaluated. Under the operating condition of dry hydrogen/air gas and the discharge current of 33 A, the average single cell voltage of fuel cell stacks with 30, 60, and 120 single cells was 0.6566, 0.6548, and 0.6552 V, respectively. The single cell range increased from 24 mV to 59 mV, which showed good consistency with the simulation results and verified the effectiveness of the simulation results. Under the operating condition of dry hydrogen/air gas with the metering coefficient of 1.5/2.5, the fuel cell stacks show excellent output performance. The output power of the three stacks reaches 1.35, 2.64, and 5.28 kW at 80 A discharge current, respectively. The results of this work provide theoretical and practical guidance for the design, assembly and evaluation of kW-scale high-temperature polymer electrolyte membrane fuel cell stacks.

The low-temperature water sprayed by the spray tower can recover the waste heat of the flue gas and purify the flue gas. In the study, the models evaluating the heat and mass exchange between flue gas and water drops, the size growth of particulate matters (PMs) caused by heterogeneous condensation and the removal of PMs in the spray tower were developed to explore the mechanisms of removing PMs within coal-fired flue gas coupled with waste heat recovery. The removal characteristics of PMs in the flue gas were also investigated under various working conditions of the spray tower. The results show that the capture mechanisms of sub-micrometer PMs in the lower part of the spray tower are mainly thermophoresis and diffusiophoresis while the capture mechanism of sub-micrometer PMs in the upper part of the spray tower is inertial collision due to water vapor condensed on the sub-micrometer PMs at the flue gas inlet temperature of 50℃, the flue gas inlet relative humidity of 100%, the water- gas ratio of 2 L/m³, the cold water temperature of 20℃, and the spray water droplet size of 550 μm. For the spray tower, the removal efficiency of PMs can be improved under the conditions of higher water-gas ratios, lower spray water temperatures, lower water droplet sizes, and higher temperature differences between flue gas and water droplets, or higher water vapor saturation levels. The spray tower has the better removal performance of PMs at the condition of water-gas ratio of 2.5 L/m³ and spray water temperatures of 10—15℃.

It is significant to understand the mechanism of operating conditions on the treatment efficiency of biological aerated filter (BAF). In this study, fiber Bragg grating (FBG) was used to monitor the shear-force distribution in BAF in situ. The effects of hydraulic retention time (HRT) and air-water ratio (A/L) on the internal flow field distribution characteristics of BAF were simulated by CFD. The results show that the increase of shear force promotes the renewal metabolism of biofilm. When HRT is 8 h and A/L is 10∶1, the amount of biofilm/shear force (M/S) is 0.17, and the effect of BAF on COD and \mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N removal rate reached 86.58% and 82.17%, respectively. The results indicate that the appropriate shear-force inside the BAF promotes the renewal and metabolism of the biofilm and improves the operating efficiency of the reactor. Therefore, this study explored the effect of shear on the reactor operational performance by M/S and provided a theoretical basis for subsequent optimization of the reactor.

The flow of slag on the side walls of a high-temperature liquid furnace strongly influences the smooth operation of the high-temperature furnace. The alkali metal in the melt has an important influence on the flow characteristics of the slag and the different alkaline components have different effects on the characteristics of the melt. Through FactSage thermodynamic calculations and molecular dynamics simulations, the effects of the relative proportions of Na₂O, K₂O, FeO, CaO, and MgO on the viscosity and microstructure of coal ash melt were studied under the condition of constant SiO₂ and Al₂O₃ contents. The study found that as M₂O/MO increased, the percentage of high polymerization units Q⁴ in the melt increased, while bridge oxygen (BO) increased and non-bridging oxygen (NBO) decreased, resulting in an increase in the polymerization degree of the melt. The order of charge compensation ability of basic oxides to melt is K₂O>Na₂O>MO. When alkali metal oxides (Na₂O, K₂O) replace FeO, CaO, MgO, some of the M⁺ breaks away from the NBO to act as charge compensating ions to produce BO. The M⁺ depolymerizes to tri-cluster oxygen (TO) that maintains the charge balance to produce BO. This structural change increases the viscosity of the melt.

High-temperature coal gas desulfurization is one of the key technologies for coal clean conversion process. Previous studies have shown that Zn-based oxide derived from Zn-Al hydrotalcite (ZnAl-HTO) can efficiently remove H₂S from high-temperature gas. However, there is a lack of qualitative and quantitative studies on the law of COS release during the desulfurization process. In this study, the possible pathways of COS release in the desulfurization process of ZnAl-HTO were investigated, the thermodynamic analysis and experimental study were also carried out. A nickel doping strategy was proposed to inhibit the formation of COS during the desulfurization process. It was shown that the main way to generate COS when zinc-aluminum hydrotalcite-based oxides to remove CO₂ from gas is the gas-solid phase catalytic reaction between H₂S and CO₂, and the amount of COS released by this way accounts for 78% of the total release. The doping of a small amount of nickel additives into the ZnAl-HTO results in no significant change in the morphology. It also effectively inhibits the COS release during desulfurization process. Under the optimal molar ratio of Zn/Ni (30), the overall desulfurization performance of ZnAl-HTO is significantly improved. Compared to sorbents without Ni-doping, the amount of COS released before H₂S-breakthrough reduced by 88%, while the corresponding sulfur capacity declined by only 1.5%.

Using chitosan (CS) as the base material and genipin as the crosslinking agent, the embolic microspheres with particle size precisely adjustable in the range of 20—90 μm are prepared by droplet microfluidic method for internal-radiation interventional therapy. First, DOTA-CS microspheres are prepared by grafting chelating agent 1,4,7,10-tetrazazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) on CS microspheres, so that the microspheres have the ability to stably load radioactive lutetium-177 (¹⁷⁷Lu). Then, DOTA-CS-¹⁷⁷Lu microspheres are prepared by the stable chelation of DOTA with ¹⁷⁷Lu. The law of size change between the emulsion templates and CS microspheres during the preparation process is explored, and the precise prediction and regulation of microsphere size are realized. The diameter variation coefficients of the prepared CS microspheres are all lower than 5%, the size is uniform, the monodispersity is good, and the swelling performance and elasticity are good. In addition, the prepared microspheres have good swelling property and elasticity. By analyzing the results of Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible absorption spectroscopy (UV-Vis) and inductively coupled plasma mass spectrometry (ICP-MS), it is concluded that the optimal modification ratio between DOTA and CS microspheres is 1∶1 (mass ratio). Scanning electron microscopy (SEM) results show that DOTA modification has no effect on the morphology and structure of CS microspheres. The results of blood compatibility test and cytotoxicity test show that the CS microspheres before and after DOTA modification have good biocompatibility. Simulating the in vivo degradation environment, the morphology and particle size of CS microspheres do not change significantly within 60 days, and only the elasticity decreases slightly. Thin layer chromatography (TLC) results show that DOTA-CS-¹⁷⁷Lu microspheres have high radiochemical purity and could maintain good radioactive stability within 15 days. These research results show that the prepared DOTA-CS-¹⁷⁷Lu microspheres present the advantages and potential for radioembolization therapy.

Thermal interface materials containing phase change materials, namely phase change thermal interface materials (PCTIMs), can directly relieve the impact of high heat flux on chip through the heat absorption. Incorporating phase change capsules and thermally conductive fillers into polymeric matrix is expected to develop the PCTIMs with good thermal reliability. In this work, the paraffin@silica nanocapsules were synthesized, followed by combining with carbon fiber, to develop polydimethylsiloxane based PCTIMs. A series of the PCTIMs were fabricated at different loadings of the nanocapsules and carbon fiber, and their phase change characteristics, thermal conductivity and hardness were measured, followed by evaluating their performance for chip heat dissipation. It is found that, the increase in mass fraction of carbon fiber resulted in the increment in both thermal conductivity and hardness for the PCTIMs, while the increase in mass fraction of the paraffin@silica nanocapsules resulted in the increment in latent heat as well as the decrease in hardness for the PCTIMs, all of which influenced the heat dissipation performance of the PCTIMs. The synergistic effects between the paraffin@silica nanocapsules and the carbon fiber make the PCTIM containing 34%(mass) of the nanocapsules and 9%(mass) of the carbon fiber achieve the best heat dissipation performance among all the prepared PCTIM samples. Moreover, the optimal PCTIM also exhibited excellent thermal reliability, thus showing potential in practical applications.

Hemihydrate wet process phosphoric acid can produce w(P₂O₅)>40%(mass) phosphoric acid but in the reaction stage, the phosphate ore is prone to coating formation, the crystal size of hemihydrate phosphogypsum is small, resulting in difficult filtration and reduced phosphorus recovery. Taking typical mid-and low-grade phosphate rock from Hubei province as raw material, the conditions such as SO{}_{\mathrm{4}}^{\mathrm{2}-} concentration, phosphoric acid concentration and reaction temperature in hemihydrate process were investigated, and the crystal phase and morphology and particle size change rule of semi-aqueous gypsum were obtained. In the hemihydrate reaction, with the concentration of sulfuric acid and phosphoric acid in the liquid phase increase, the hemihydrate phosphogypsum is more prone to phase transformation. The morphology of hemihydrate phosphogypsum changes from hexagonal prism to rod and flake, and the particle size decreases from 70 μm to 10 μm. Under optimal conditions, the content of P, F and other elements in hemihydrate phosphogypsum can be effectively reduced. The P₂O₅ content of hemihydrate phosphogypsum was reduced to 1.39%(mass) and the main form of P was insoluble phosphate. The F content was reduced to 0.44%(mass), which existed in hemihydrate phosphogypsum in the form of poorly soluble substances such as CaF₂ and AlF₃. The form of impurities is simple, which is convenient for the subsequent purification and utilization of gypsum. The above research brings new ideas for the stable operation of hemihydrate process and the quality improvement of hemihydrate phosphogypsum.

To solve the problems of easy leakage, low thermal conductivity and poor mechanical properties of phase change materials, flexible phase change films were prepared by solution blending method of PEG/PLA/Al₂O₃ with biodegradable poly(lactic acid) (PLA) as the substrate, poly(ethylene glycol) (PEG) as the phase change working fluid and alumina (Al₂O₃) as the thermal conductivity additive for thermal energy storage. The phase change films could be curled and folded arbitrarily without breaking, showing good flexibility. The results of the tests on thermal properties, thermal conductivity and degradation properties showed that PEG and PLA had good compatibility, PLA as a supporting substrate effectively prevented the leakage of PEG liquid, and the prepared flexible phase change films had good shape stability. The latent heats during melting and solidification of PEG/PLA were 120.2 J/g and 128.5 J/g, respectively, and the latent heat retention rates were 62.2% and 67.6%, respectively. Adding 20% alumina, the latent heat value was only reduced by 12.5%, while the thermal conductivity was increased by 75%, and the heat transfer efficiency was significantly improved. The degradation rate of PEG/PLA was significantly higher than that of PLA, and the PEG/PLA film could be completely degraded in NaOH solution for about 4 h, which has good environmental friendliness.

In order to reduce the impact of refined oil pipeline accidents and better understand the flow of refined oil in the soil, an indoor visualization experiment device is built. Based on digital image processing technology, the saturation of diesel oil that is difficult to measure in real time and the HSI color mode that is easy to obtain are established. The functional relationship between each component is verified by sampling experiments. The results show that H (hue) and S (saturation) can be used as indicators to determine whether oil is contained in porous media. The oil saturation can be characterized with an accuracy of up to 3.12% by S in the low saturation region. The oil saturation can be characterized within ±2% by I (intensity) in the high saturation region. A dynamic, real-time, non-invasive laboratory technique of visualizing the migration of refined oil within the soil is established, which can support the evolution of the leakage process. The research results make up for the technical deficiency in China regarding the visualization of oil leakage dispersion in soil. This is of great significance to effectively control the environmental pollution caused by refined oil and reduce the hazards caused by oil leakage.

The nuclear power industry is becoming more complex in terms of process. However, the safety monitoring of the shell and tube heat exchanger equipment in the power station still remains in the direct monitoring and indirect characterization of the performance parameters, and it is difficult to achieve accurate fault diagnosis and early warning. In this paper, a virtual sensing method for leakage fault of shell and tube heat exchanger is proposed. Firstly, by analyzing the leakage mechanism of shell and tube heat exchanger and the influence of leakage on performance indexes and monitoring parameters, a virtual sensing reasoning model for two working conditions of heat exchanger leakage and flange leakage is constructed. The model can not only judge the leakage state and leakage category, but also realize direct characterization of performance parameters. In order to verify the proposed model, a leakage fault test rig of shell and tube heat exchanger is built. The results show that the model can diagnose the leakage with a leakage rate of 1.8%, and its diagnosis error is no more than 11.32% for different working conditions, with high accuracy and reliability.