It is known that salt ions are abundant in the natural environment where natural gas hydrates are located; thus, it is essential to investigate the self-preservation effect of salt ions on methane hydrates. The dissociation behaviors of gas hydrates formed from various NaCl concentration solutions in a quartz sand system at 268.15 K were investigated to reveal the microscopic mechanism of the self-preservation effect under different salt concentrations. Results showed that as the salt concentration rises, the initial rate of hydrate decomposition quickens. Methane hydrate hardly shows self-preservation ability in the 3.35% (mass) NaCl and seawater systems at 268.15 K. Combined the morphology of hydrate observed by the confocal microscope with results obtained from in situ Raman spectroscopy, it was found that during the initial decomposition stage of gas hydrate below the ice point, gas hydrate firstly converts into liquid water and gas molecules, then turns from water to solid ice rather than directly transforming into solid ice and gas molecules. The presence of salt ions interferes with the ability of liquid water to condense into solid ice. The results of this study provide an important guide for the mechanism and application of the self-preservation effect on the storage and transport of gas and the exploitation of natural gas hydrates.

Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming, which could influence the formation of reaction intermediates and modify catalytic behaviors. Herein, the Ni/biochar as well as two comparative catalysts, Ni/Al₂O₃ and Ni/SiO₂, with low nickel loading (2% (mass)) was conducted to probe involvement of the varied carriers in the steam reforming. The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO₂ and Ni/Al₂O₃, as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C, resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance. In converse, strong adsorption of aliphatic intermediates over Ni/Al₂O₃ and Ni/SiO₂ induced serious coking with polymeric coke as the main type (21.5% and 32.1%, respectively), which was significantly higher than that over Ni/biochar (3.9%). The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity. The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam, which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al₂O₃ and Ni/SiO₂ catalysts.

In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction, a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by acetonitrile. The accuracy of five prediction methods, UNIFAC (UNIQUAC Functional-group Activity Coefficients), UNIFAC-LL, UNIFAC-LBY, UNIFAC-DMD and COSMO-RS, applied to the butadiene extraction process was verified using partial phase equilibrium data. The results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing system. COSMO-RS-predicted multiple systems showed good accuracy, and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS method. The predicted phase equilibrium data were checked for consistency. The NRTL-RK (non-Random Two Liquid-Redlich-Kwong Equation of State) and UNIQUAC thermodynamic models were used to correlate the phase equilibrium data. Industrial device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction process. The simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2% compared to that using the commercial simulation software, Aspen Plus and its database. The average deviation was much smaller than that of the simulations using the Aspen Plus database (>10%), indicating that the obtained phase equilibrium data are highly accurate and reliable. The best phase equilibrium data and thermodynamic model parameters for butadiene extraction are provided. This improves the accuracy and reliability of the design, optimization and control of the process, and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.

Ensuring the consistency of electrode structure in proton-exchange-membrane fuel cells is highly desired yet challenging because of wide-existing and unguided cracks in the microporous layer (MPL). The first thing is to evaluate the homogeneity of MPL with cracks quantitatively. This paper proposes the homogeneity index of a full-scale MPL with an area of 50 cm², which is yet to be reported in the literature to our knowledge. Besides, the effects of the carbon material and surfactant on the ink and resulting MPL structure have been studied. The ink with a high network development degree produces an MPL with low crack density, but the ink with high PDI produces an MPL with low crack homogeneity. The polarity of the surfactant and the non-polarity of polytetrafluoroethylene (PTFE) are not mutually soluble, resulting in the heterogeneous PTFE distribution. The findings of this study provide guidelines for MPL fabrication.

The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry. Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux, and selectivity. In this study, the hyperbranched polymer (HBP) was deposited on the outer surface of a polyvinylidene fluoride (PVDF) hollow-fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane structure. The obtained HBP/PVDF hollow-fiber-composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50% (mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m^-2·h^-1, with a separation factor of 4.1 at 60 ℃. Therefore, the HBP/PVDF hollow-fiber-composite membrane has great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures.

Copper-based metal-organic frameworks (Cu-MOFs) are a promising multiphase catalyst for catalyzing C-S coupling reactions by virtue of their diverse structures and functions. However, the unpleasant odor and instability of the organosulfur, as well as the mass-transfer resistance that exists in multiphase catalysis, have often limited the catalytic application of Cu-MOFs in C-S coupling reactions. In this paper, a Cu-MOFs catalyst modified by cetyltrimethylammonium bromide (CTAB) was designed to enhance mass transfer by increasing the adsorption of organic substrates using the long alkanes of CTAB. Concurrently, elemental sulfur was used to replace organosulfur to achieve a highly efficient and atom-economical multicomponent C-S coupling reaction.

The coal-to-ethanol process, as the clean coal utilization, faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol. Referring to at least eight columns, the synthesis of the ethanol distillation system is impracticable for exhaustive comparison and difficult for conventional superstructure-based optimization as rigorous models are used. This work adopts a superstructure-based framework, which combines the strategy that adaptively selects branches of the state-equipment network and the parallel stochastic algorithm for process synthesis. High-performance computing significantly reduces time consumption, and the adaptive strategy substantially lowers the complexity of the superstructure model. Moreover, parallel computing, elite search, population redistribution, and retention strategies for irrelevant parameters are used to improve the optimization efficiency further. The optimization terminates after 3000 generations, providing a flowsheet solution that applies two non-sharp splitting options in its distillation sequence. As a result, the 59-dimension superstructure-based optimization was solved efficiently via a differential evolution algorithm, and a high-quality solution with a 28.34% lower total annual cost than the benchmark was obtained. Meanwhile, the solution of the superstructure-based optimization is comparable to that obtained by optimizing a single specific configuration one by one. It indicates that the superstructure-based optimization that combines the adaptive strategy can be a promising approach to handling the process synthesis of large-scale and complex chemical processes.

Fabric multifunctionality offers resource savings and enhanced human comfort. This study innovatively integrates cooling, heating, and antimicrobial properties within a Janus fabric, surpassing previous research focused solely on cooling or heating. Different effects are achieved by applying distinct coatings to each side of the fabric. One graphene oxide (GO) coating exhibits exceptional light-to-heat conversion, absorbing and transforming light energy into heat, thereby elevating fabric temperature by 15.4 ℃, 22.7 ℃, and 43.7 ℃ under 0.2, 0.5, and 1 sun irradiation, respectively. Conversely, a hydrogel coating on one side absorbs water, facilitating heat dissipation through evaporation upon light exposure, reducing fabric temperature by 5.9 ℃, 8.4 ℃, and 7.1 ℃ in 0.2, 0.5, and 1 sun irradiation, respectively. Moreover, both sides of Janus fabric exhibit potent antimicrobial properties, ensuring fabric hygiene. This work presents a feasible solution to address crucial challenges in fabric thermal regulation, providing a smart approach for intelligent adjustment of body comfort in both summer and winter. By integrating heating and cooling capabilities along with antimicrobial properties, this study promotes sustainable development in textile techniques.

Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer, increased yield, safety, and simplicity of control. However, immobilizing catalysts in microreactors remains challenging. In this investigation, a technique for creating Cu₂O/montmorillonite catalyst coating, using electrostatic attraction for layer-by-layer self-assembly, was proposed. The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite, alongside layer-by-layer coating times. The Cu₂O nanoparticles were immobilized using the flow deposition approach. The resulting Cu₂O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone. The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants, temperature, residence time, and Cu₂O loading. The maximum glycerol conversion observed was 47.6%, with a 27% selectivity toward dihydroxyacetone. The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing, which can serve as a foundation for the future application of microreactors in glycerol conversion.

Silicone rubber (SR) is widely used in the field of electronic packaging because of its low dielectric properties. In this work, the porosity of the SR was improved, and the dielectric constant of the SR foam was reduced by adding expanded microspheres (EM). Then, the thermal conductivity of the system was improved by combining the modified boron nitride (f-BN). The results showed that after the f-BN was added, the dielectric constant and dielectric loss were much lower than those of pure SR. Micron-sized modified boron nitride (f-mBN) improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride (f-nBN), but f-nBN improved the volume resistivity, tensile strength, and thermal stability of the SR better than f-mBN. When the mass ratio of f-mBN and f-nBN is 2:1, the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^-1·K^-1, which is 6.5 times that before the addition. The heat release rate and fire growth index are the lowest, and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN.

In order to comprehend the applicability of microwave irradiation for recovering coalbed methane, it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of metamorphism. In this work, the carbon molecular sieve combined with KMnO₄ oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees, which can serve as model substances toward coals. Afterwards, the microwave irradiation dependences of pores, functional groups, and high-pressure methane adsorption characteristics of model substances were studied. The results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups, which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve; meanwhile, naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 nm. These alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%, suggesting that microwave irradiation could promote methane desorption. Moreover, the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH₄ diffusion. In summary, the oxidized carbon molecular sieve can act as model substances toward coals with different ranks. Additionally, microwave irradiation is a promising technology to enhance coalbed methane recovery.

A green environmental protection and enhanced leaching process was proposed to recover all elements from spent lithium iron phosphate (LiFePO₄) lithium batteries. In order to reduce the influence of Al impurity in the recovery process, NaOH was used to remove impurity. After impurity removal, the spent LiFePO₄ cathode material was used as raw material under the H₂SO₄ system, and the pressure oxidation leaching process was adopted to achieve the preferential leaching of lithium. The E-pH diagram of the Fe-P-Al-H₂O system can determine the stable region of each element in the recovery process of spent LiFePO₄ Li-batteries. Under the optimal conditions (500 r·min^-1, 15 h, 363.15 K, 0.4 MPa, the liquid-solid ratio was 4:1 ml·g^-1 and the acid-material ratio was 0.29), the leaching rate of Li was 99.24%, Fe, Al, and Ti were 0.10%, 2.07%, and 0.03%, respectively. The Fe and P were precipitated and recovered as FePO₄·2H₂O. The kinetic analysis shows that the process of high-pressure acid leaching of spent LiFePO₄ materials depends on the surface chemical reaction. Through the life cycle assessment (LCA) of the spent LiFePO₄ whole recovery process, eight midpoint impact categories were selected to assess the impact of recovery process. The results can provide basic environmental information on production process for recycling industry.

Lymph node targeting is a commonly used strategy for particulate vaccines, particularly for Pickering emulsions. However, extensive research on the internal delivery mechanisms of these emulsions, especially the complex intercellular interactions of deformable Pickering emulsions, has been surprisingly sparse. This gap in knowledge holds significant potential for enhancing vaccine efficacy. This study aims to address this by summarizing the process of lymph-node-targeting transport and introducing a dissipative particle dynamics simulation method to evaluate the dynamic processes within cell tissue. The transport of Pickering emulsions in skeletal muscle tissue is specifically investigated as a case study. Various factors impacting the transport process are explored, including local cellular tissue environmental factors and the properties of the Pickering emulsion itself. The simulation results primarily demonstrate that an increase in radial repulsive interaction between emulsion particles can decrease the transport efficiency. Additionally, larger intercellular gaps also diminish the transport efficiency of emulsion droplet particles due to the increased motion complexity within the intricate transport space compared to a single channel. This study sheds light on the nuanced interplay between engineered and biological systems influencing the transport dynamics of Pickering emulsions. Such insights hold valuable potential for optimizing transport processes in practical biomedical applications such as drug delivery. Importantly, the desired transport efficiency varies depending on the specific application. For instance, while a more rapid transport might be crucial for lymph-node-targeted drug delivery, certain applications requiring a slower release of active components could benefit from the reduced transport efficiency observed with increased particle repulsion or larger intercellular gaps.

This work provides an overview of distillation processes, including process design for different distillation processes, selection of entrainers for special distillation processes, system integration and intensification of distillation processes, optimization of process parameters for distillation processes and recent research progress in dynamic control strategies. Firstly, the feasibility of using thermodynamic topological theories such as residual curve, phase equilibrium line and distillation boundary line to analyze different separation regions is discussed, and the rationality of distillation process design is discussed by using its feasibility. Secondly, the application of molecular simulation methods such as molecular dynamics simulation and quantum chemical calculation in the screening of entrainer is discussed for the extractive distillation process. The thermal coupling mechanism of different distillation processes is used to explore the process of different process intensifications. Next, a mixed integer nonlinear optimization strategy for the distillation process based on different algorithms is introduced. Finally, the improvement of dynamic control strategies for different distillation processes in recent years is summarized. This work focuses on the application of process intensification and system optimization in the design of distillation process, and analyzes the challenges, prospects, and development trends of distillation technology in the separation of multicomponent azeotropes.

The technological revolution has spawned a new generation of industrial systems, but it has also put forward higher requirements for safety management accuracy, timeliness, and systematicness. Risk assessment needs to evolve to address the existing and future challenges by considering the new demands and advancements in safety management. The study aims to propose a systematic and comprehensive risk assessment method to meet the needs of process system safety management. The methodology first incorporates possibility, severity, and dynamicity (PSD) to structure the “51X” evaluation indicator system, including the inherent, management, and disturbance risk factors. Subsequently, the four-tier (risk point-unit-enterprise-region) risk assessment (RA) mathematical model has been established to consider supervision needs. And in conclusion, the application of the PSD-RA method in ammonia refrigeration workshop cases and safety risk monitoring systems is presented to illustrate the feasibility and effectiveness of the proposed PSD-RA method in safety management. The findings show that the PSD-RA method can be well integrated with the needs of safety work informatization, which is also helpful for implementing the enterprise's safety work responsibility and the government's safety supervision responsibility.

It is quite important to ensure the safety and sustainable development of nuclear energy for the treatment of radioactive wastewater. To treat radioactive wastewater efficiently and rapidly, two multi-amine β-cyclodextrin polymers (diethylenetriamine β-cyclodextrin polymer (DETA-TFCDP) and triethylenetetramine β-cyclodextrin polymer (TETA-TFCDP)) were prepared and applied to capture uranium. Results exhibited that DETA-TFCDP and TETA-TFCDP displayed the advantages of high adsorption amounts (612.2 and 628.2 mg·g^-1, respectively) and rapid adsorption rates, which can reach (88 ±1)% of their equilibrium adsorption amounts in 10 min. Moreover, the adsorbent processes of DETA-TFCDP and TETA-TFCDP on uranium(VI) followed the Langmuir model and pseudo-second-order model, stating they were mainly chemisorption and self-endothermic. Besides, TETA-TFCDP also showed excellent selectivity in the presence of seven competing cations and could be effectively reused five times via Na₂CO₃ as the desorption reagent. Meanwhile, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy illustrated that the enriched multi-amine groups and oxygen-containing functional groups on the surface of TETA-TFCDP were the main active sites for capturing uranium(VI). Hence, multi-amine β-cyclodextrin polymers are a highly efficient, rapid, and promising adsorbent for capturing uranium(VI) from radioactive wastewater.

A huge amount of energy is always consumed to separate the ternary azeotropic mixtures by distillations. The heterogeneous azeotropic distillation and the pressure-swing distillation are two kinds of effective technologies to separate heterogeneous azeotropes without entrainer addition. To give better play to the synergistic energy-saving effect of these two processes, a novel pressure-swing-assisted ternary heterogeneous azeotropic distillation (THAD) process is proposed firstly. In this process, the ternary heterogeneous azeotrope is decanted into two liquid phases before being refluxed into the azeotropic distillation column to avoid the aqueous phase remixing, and three columns' pressures are modified to decrease the flowrates of the recycle streams. Then the dividing wall column and heat integration technologies are introduced to further reduce its energy consumption, and the pressure-swing-assisted ternary heterogeneous azeotropic dividing-wall column and its heat integration structure are achieved. A genetic algorithm procedure is used to optimize the proposed processes. The design results show that the proposed processes have higher energy efficiencies and lower CO₂ emissions than the published THAD process.

Heat integration is important for energy-saving in the process industry. It is linked to the persistently challenging task of optimal design of heat exchanger networks (HEN). Due to the inherent highly nonconvex nonlinear and combinatorial nature of the HEN problem, it is not easy to find solutions of high quality for large-scale problems. The reinforcement learning (RL) method, which learns strategies through ongoing exploration and exploitation, reveals advantages in such area. However, due to the complexity of the HEN design problem, the RL method for HEN should be dedicated and designed. A hybrid strategy combining RL with mathematical programming is proposed to take better advantage of both methods. An insightful state representation of the HEN structure as well as a customized reward function is introduced. A Q-learning algorithm is applied to update the HEN structure using the ϵ-greedy strategy. Better results are obtained from three literature cases of different scales.

The pyrolysis process of Shendong coal (SD) was first studied by combining the characteristics of thermal gravimetric (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and Gray-King assay (G-K). The results show that the order of coke yields is G-K (76.35% (mass))>TG (73.11% (mass))>Py (70.03% (mass)). G-K coke yield caused by condensation reaction and secondary reaction accounts for 3.08% (mass) and 3.24% (mass), respectively. Compared with slow pyrolysis, fast pyrolysis has stronger fracture ability to coal molecules and can obtain more O-compounds, mono-ring aromatics and aliphatics. Especially, the content of phenolics increases significantly from 15.49% to 35.17%, but the content of multi-ring aromatics decreases from 23.13% to 2.36%. By comparing the compositions of Py primary tar and G-K final tar, it is found that secondary reactions occurred during G-K pyrolysis process include the cleavage of alkane and esters, condensation of mono-ring aromatics with low carbon alkene, ring opening, isomerization of tri-ring aromatics, hydrogenation of aromatics and acids.