The accelerating global “decarbonization” process makes product carbon footprint a key indicator of evaluating the environmental responsibilities of companies and products. As a key field for carbon reduction and a pillar industry of the national economy in China, the carbon footprint evaluation in the petrochemical industry is not only necessary for promoting the green transformation of the industry and coping with new barriers in international trade but also an important way for achieving the goal of carbon peak and carbon neutrality. This review starts with the core concepts related to carbon footprint, and through systematic analysis the life cycle assessment methods, life cycle carbon footprint assessment methods, and petrochemical industry carbon inventory assessment framework, it clarifies the development context of current carbon footprint assessment methods. The characteristics of international standards and mainstream tools related are further analyzed to provide references for establishing international mutually recognized carbon footprint accounting standards and databases for key products in the petrochemical industry. Finally, the typical application cases and bottlenecks in carbon footprint evaluation within the petrochemical industry are summarized, which points out directions for further development in the future field.

Methylaluminoxane (MAO) is an important co-catalyst in various olefin polymerization systems, but it remains challenging to produce MAO economically and MAO has low solubility and poor stability in aliphatic hydrocarbon solvents. Therefore, modifying MAO to address the above limitations is of significant importance. The review presents the main techniques for MAO modification, including hydrolytic and non-hydrolytic methods, with a focus on the design and synthesis of modified methylaluminoxane (MMAO) using 3D printing in continuous flow. This flow synthesis platform consists of an isobutylaluminoxane (IBAO) synthesis module, an IBAO and TMA fast complexation module, and anisobutyl-modified product iBu-MMAO synthesis module. Mitigating the risk of solid clogging and a thermal runaway, this approach achieves continuous synthesis of MMAO more safely and stably, with yields up to 80%, and the product has comparable co-catalytic activity to commercial products. On this basis, the analysis and detection methods of MMAO and the application of its series of products in polymerization systems are reviewed, providing theoretical support and technical guidance for the synthesis and application of MMAO.

Fluidized bed technology is widely used in industry. Industrial processes such as natural uranium conversion, direct reduction ironmaking, and chemical chain combustion use heavy particles with a particle density of more than 4.0 g/cm³. However, in traditional chemical and energy industries, lightweight fluidized bed particles with smaller density are widely used. This article reviews the application background of high-density particle fluidization technology in some industries,which particle densities are beyond 4.0 g/cm³, and explores the impact of high-density particle fluidization quality on system performance. Subsequently, the article reviews the research progress in high-density particle fluidization, highlighting that both experimental measurements and numerical simulations indicate significant differences in the fluidization behavior between high-density and low-density particles. However, existing studies on the fluidization characteristics of high-density particles remain insufficient, particularly regarding the flow characteristics and differences compared to low-density particles. Finally, combined with the needs of related industrial processes, this article focuses on the basic research content of heavy particle fluidization that should be supplemented in the near future.

The research of non-equalized system transmission in the microchannel of liquid fluids clarify the mechanism of mass transfer, further improve the efficiency of the quality transmission, and promote the industrialization application of micro-channel devices in the fields of continuous mobile chemical synthesis, biomedical and solvent extraction. The parameters and influencing factors of mass transfer in microchannels are introduced, and the methods and relevant principles are summarized, including the simulation methods for exploring two-phase flow behavior, in-phase and interphase mass transfer, the offline experimental method for evaluating the overall mass transfer performance of microchannel devices, and the online experimental method for real-time detection of the fluid velocity and concentration field in microchannels. The possible development of simulation and experimental methods for the study of mass transfer in liquid-liquid systems in microchannels is also proposed.

CO₂ emissions from industrial flue gases are among the primary sources of global carbon emissions and are key areas for the application of carbon capture technologies. The research progress on scale-up of membrane technology in the field of carbon capture from industrial flue gas is reviewed. First, the working principles of CO₂/N₂ separation membranes are introduced. The sources and compositions of flue gases from fossil fuel power plants, cement plants, and steel plants are summarized, and the challenges faced by membrane separation technology in the carbon capture process of these flue gases are discussed. Next, the current status and issues related to the scale-up preparation of flue gas carbon capture membranes, research on flue gas carbon capture membrane modules, and scale-up testing of industrial flue gas carbon capture membranes are introduced and analyzed. Finally, the development trends in membrane technology for industrial flue gas carbon capture are discussed, including the scale-up of CO₂ separation mixed-matrix membranes, the development of CO separation membranes for steel mill flue gases, and the optimization of membrane modules. This review aims to provide scholars with the latest research developments and future directions in the scale-up of industrial flue gas carbon capture membranes.

Recycling and enhancing the application value of retired polyethylene terephthalate (PET) is of great significance for reducing resource waste and environmental pollution. This paper reviews the research progress of recycling and high-value reuse of retired PET, summarizes the recycling methods including landfill, incineration, pyrolysis, and bio-enzyme degradation, and deeply discusses chemical recycling and catalytic recycling technologies such as photo-, electro-, and hydrogenolysis, focusing on the transformation path of retired PET into high-value products such as recycled PET, copolyesters, small molecule chemicals, composite materials, and other materials. By adopting an integrated depolymerization-repolymerization process, the separation steps in the depolymerization of retired PET can be effectively reduced, thereby lowering costs while achieving product upgrading. With the improvement of pretreatment and depolymerization efficiency in sorting and impurity removal of retired PET, the construction of closed-loop recycling systems, the development of efficiency-enhancing additives, and the exploration of efficient biological depolymerization technologies, the industrialization of high-value reuse of retired PET will be greatly promoted.

The molecular composition of the direct coal liquefaction products is complex. It is of great significance to explore the detailed molecular composition of the direct coal liquefaction products for the optimization of the coal-to-oil process. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry/hydrogen flame ionization detector (GC×GC-TOF MS/FID) method was established for the qualitative and quantitative characterization of composition and structure of coal liquefaction oil and its hydrogenation process products at the molecular level,which revealed the hydrogenation reaction law of coal liquefaction. The molecular composition characterization technology of GC×GC-TOF MS liquefied oil preliminarily solved the problem that multiple compounds co-escape in one-dimensional chromatography due to the same retention time through the difference of molecular polarity in two dimensions. After hydrogenation of coal liquefaction oil, the content of cycloalkanes increases and the content of aromatics decreases. In the circulating solvent, the hydrogen dissolving and supplying hydrogen is mainly achieved through the hydrogenation of three-ring and four-ring aromatic molecules to varying degrees. In addition, the GC×GC-TOF MS/FID characterization technology of hydrocarbon group composition was also established for direct coal liquefaction naphtha and diesel. Compared with the group composition content of straight-run hydrogenated diesel and gasoline, the direct coal liquefaction products diesel and gasoline contain more monocyclic, bicyclic and tricyclic alkanes.

Under high inlet gas volume fraction, the pressurization of the multiphase pump deteriorates sharply, which poses a threat to the safe and stable operation of the chemical production process. This study uses two test methods, surging test and mapping test, to comprehensively explore the impact of multiple operating parameters on the overall and inter-stage gas-liquid two-phase pressurization characteristics of a three-stage mixed-flow multiphase pump. The results show that with the increase of liquid flow rate, the downward trend of the pressurization curve caused by the deterioration of the performance of the three booster stages gradually disappears. The significant deterioration of the pressurization performance of the multistage multiphase pump is mainly attributed to the sharp decline in the performance of the first booster stage. Increasing liquid flow rate can effectively reduce gas accumulation, and its positive promoting effect on pressurization performance significantly exceeds the negative effect caused by flow separation, so pressurization presents a sudden upward trend with the liquid flow curve. Increasing the inlet pressure helps to alleviate the negative impact of air mass accumulation on pressurization performance.

The impeller is one of the most important components of gas-liquid stirred tank, and its structure and combination significantly affect the gas-liquid dispersion and mass transfer performance. Combining the cold mold experiment and CFD-PBM numerical simulation, the interaction relationship between the multi-layer blades of the gas-liquid stirring tank and the optimal blade combination form were obtained. The research results indicate that the radial impeller, as the bottom impeller, has the greatest impact on gas dispersion and bubble breakage, the middle axial flow impeller has a relatively small effect on the shear stress of the bottom impeller, while the axial convergence generated by the top axial flow impeller would weaken the shear stress of the middle impeller. The arrangement and combination of multiple impellers can affect the power consumption of each impeller, with the top impeller having the most significant impact on the power of the middle impeller. HEDT, as the bottom impeller, has low power consumption and good gas dispersion effect. KYA, as the middle impeller, can enhance axial convergence, reduce local eddies, and further crush bubbles. PBT, as the top impeller, has low power consumption and control large circulation flow structures. The HEDT+KYA+PBT impeller combination balance power consumption, gas phase dispersion, and gas-liquid mass transfer, and has the highest unit power consumption gas holdup and average volumetric mass transfer coefficient, making it the optimal impeller combination. These research results can provide some theoretical guidance for the design and optimization of multiple impellers in gas-liquid stirred tanks.

The preparation of aqueous two-phase droplets in the improved necking T-shaped microchannel and step T-shaped microchannel embedded capillary was studied, and the two microchannels were compared based on the droplet size. The jet-slug flow and jet-drop flow were observed, and the transition between flow patterns is controlled by the two-phase flow rates. In the step T-shaped microchannel embedded capillary, the generation range and stability of the droplets are obviously better than that of the necking T-shaped microchannel. The variations of droplet formation size in the two microchannels are similar, which decreases with the increase of continuous phase flow rate and increases with the increase of dispersed phase flow rate. However, the droplet size generated in the step T-shaped microchannel embedded capillary is smaller than that in the necking T-shaed microchannel. The prediction models of droplet size are established, which have good prediction performance in both microchannels.

Electrolysis for hydrogen production is a key driver for the future of green energy. The filter-press water electrolyzer is a widely-used industrial hydrogen production device, where the uniform distribution of electrolytes is crucial for extending electrode lifespan and enhancing electrolysis efficiency. However, the flow field distribution uniformity in traditional mastoid plates is poor, resulting in low electrolysis efficiency and even local overtemperature, which leads to safety problems such as electrode ablation. To overcome this problem and enhance the flow distribution within the electrode plates, a “dense in center, sparse in sides” convex-concave unit distribution strategy for mastoid plates is proposed. First, a visual experimental platform for the mastoid plates was constructed to study the distribution of alkaline solution residence time and validate the simulations. Subsequently, the single-phase flow characteristics of four different dimpled plate structures were simulated, and the flow dead zones were quantitatively characterized using a coupled particle tracking algorithm. The results show that the new convex-concave unit distribution strategy can make the electrolyte flow field inside the electrolytic cell more uniform, minimizing electrolyte backflow and reducing the formation of dead zones. Furthermore, this strategy enhances system flexibility to accommodate a broader range of flow conditions.

During the experiment using the gas delivery system, the actual flow rate often deviates, and the deviation value is different under different inlet pressures and system pressure differences, which will affect the accuracy of the experimental results in certain cases. The experimental results can be corrected by error prediction. This research uses a nitrogen conveying system to analyze and predict errors by varying the inlet pressure, differential pressure, and flow rate value and range and measuring the actual flow rate. It is shown that the system differential pressure has less effect on the flow control. And the increase of inlet pressure needs to be used with the back pressure valve thus improving the accuracy of the system, so the inlet pressure can be increased to make the deviation value smaller. Meanwhile, a universal prediction model of error value and flow rate value is proposed based on the theoretical derivation and experimental results, which can accurately predict the actual flow rate, and provides a new idea for the error analysis and precise control of a gas conveying system.

Clarifying the temperature distribution pattern of horizontal wells is crucial to interpreting natural gas production using well temperature data. This study investigated the impact of gas-liquid flow rate and the number of perforations on temperature distribution within a horizontal pipeline, utilizing a multiphase flow experimental setup. The study revealed that temperature fluctuations in the horizontal section are closely influenced by the gas inflow through the perforations, gas-water content, and the temperature drop across adjacent perforations. Correlation equations for predicting the flow rate and water content based on the temperature differences were established. Experimental results indicate that an increase in gas flow reduces the temperature beneath the perforations and decreases the overall temperature profile of the pipe section. Higher water content significantly reduces the temperature drop as the gas passes through the perforations, with the effect disappearing when the volumetric water content approaches 9% under experimental conditions. In addition, when airflow passes through multiple perforations simultaneously, the variation of the downstream airflow temperature drop is influenced by the temperature drop of the upstream airflow. The downstream temperature drop increases as the gas inflow ratio between neighboring perforations increases. When the downstream perforation encounters the gas-liquid flow, the effect of the upstream airflow temperature drop disappears as the water content in the downstream flow increases. The results show that the temperature drop from the upstream airflow significantly impacts the downstream temperature drop during the early stage of production, which should not be ignored when utilizing the temperature data for production calculations. However, this influence diminishes considerably in the presence of high water content. This study not only clarifies the characteristics of the temperature profile during production in horizontal wells, but also deepens the understanding of temperature drop variations caused by gas-liquid interactions. Additionally, it contributes to more accurate utilization of temperature data for production analysis, offering significant value for both engineering applications and academic research.

In order to solve the key technical problems of the thermochemical sulfur-iodine (S-I) cycle and the H₂S splitting cycle for hydrogen production, the mixing characteristics of the Bunsen reaction products (HI/H₂SO₄/H₂O/toluene liquid-liquid two-phase mixture) in the microchannel were investigated by numerical simulation using ANSYS-FLUENT. The relationship between the two-phase mixing in the microchannel and the inlet mode, inlet flow rate, and two-phase flow rate ratio was systematically analyzed, and the strengthening effect of adding obstacles in the microchannel on the two-phase mixing was discussed. The results show that the mixing is more effective when two phases enter the channel in an upper and lower stratified manner. Increasing the flow rates of two phases can significantly increase the mixing degree but the channel pressure loss increases accordingly. When the two-phase flow rate ratio is 1∶1 and the flow rate is 0.035 m/s, the mixing degree reaches the maximum value of 88.72% while the pressure loss is relatively low. Setting obstacles inside the channel can form periodic eddy currents, which can effectively shorten the two-phase mixing time and strengthen the two-phase mixing. Compared to semicircular barriers, rectangular barriers provide a greater promotion of mixing but have a greater pressure loss.

The gas diffusion layer (GDL) porous media is composed of two components with significantly different structures: the porous transport layer (PTL) and the microporous layer (MPL). The PTL/MPL interface has a non-negligible impact on the performance of the battery. To deeply investigate the effect of mechanical stress on the transport properties at the PTL/MPL interface. This study first reconstructs the three-dimensional microscale structure of the interface by using X-ray tomography to characterize the commercial GDL. Subsequently, the finite element method is utilized to simulate the distribution of stress, strain, and microstructure parameters at the interface under different mechanical compression ratios. Finally, the relationship between the mechanical compression ratio and the anisotropic effective transport properties is obtained by using a pore scale model. It is found that a 40% mechanical compression ratio leads to a 41% reduction in porosity and nearly 62% decrease in average pore size at the interface. In addition, the tortuosity increases by 61%, the gas diffusivity decreases by 57%, and the conductivity doubles in the in-plane direction. The tortuosity increases by a factor of two, the gas diffusivity decreases by 67%, and the effective conductivity increases by a factor of three in the through-plane direction.

Selective etching of Si₃N₄ in a stacked structure of Si₃N₄ and SiO₂ using phosphoric acid as an etchant is one of the most critical steps in the manufacturing process of 3D NAND flash memory chips. With the increasing number of stacked layers, diffusion limitation becomes important and the concentration gradient of the etching product H₂SiO₃ becomes large, which brings the problems of low etching selectivity and serious oxide regrowth in this etching process. Facing these above-mentioned problems, this work combines characterizations and kinetics experiments to obtain the kinetics models of Si₃N₄ and SiO₂ etched by phosphoric acid with or without the influence of H₂SiO₃. The results show the etch of Si₃N₄ is the nucleophilic attack of Si by the nucleophilic reagents, like water and phosphoric acid. The activation energies for etching Si₃N₄ and SiO₂ by phosphoric acid are 60.71 kJ·mol^-1 and 66.90 kJ·mol^-1, indicating the energy required to break Si—O bond is larger than that to break Si—N bond under the attack of nucleophilic reagents. The etching kinetics of Si₃N₄ and SiO₂ with the influence of H₂SiO₃ concentration show that the etching rates of Si₃N₄ and SiO₂ decrease with the increase of H₂SiO₃ concentration, and the etching rate of SiO₂ is more sensitive to the change of H₂SiO₃ concentration. The results in this work should provide some fundamental data and theoretical understanding for the optimal design of phosphate wet etching process for manufacturing 3D NAND.

The selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) involves serial hydrogenation reactions, where transport phenomena within the catalyst pellets and throughout the catalyst bed play a pivotal role in determining catalytic performance. Hence, meticulous structural design of pellet catalysts is imperative for their industrial viability. In this study, the kinetic equations were first derived from experimental data for the DMO hydrogenation to MG using Ag/SiO₂ catalyst. Subsequently, a comprehensive two-dimensional bed-particle dual-scale model was developed to elucidate the transport and reaction dynamics of DMO hydrogenation at both scales. The impact of the active component distribution inside catalyst pellets on their catalytic performance in a single-tube reactor was investigated. Simulation results show that there is a serious problem of excessive hydrogenation of MG in reactors using uniform catalysts. Using eggshell catalysts can effectively suppress the formation of excessive hydrogenation product ethylene glycol, improve the yield of MG, and can reduce the dosage of active components and significantly improve the economic benefits of the DMO hydrogenation to MG process. These findings offer fundamental insights and practical guidance for the design and fabrication of industrial catalysts tailored for DMO hydrogenation to MG.

Firstly, the preferred reaction domains and reaction pattern of light olefins from Daqing crude oil were obtained through experiment evaluation. Then a molecular-level kinetic modeling has been established based on intelligent refining technology, which includes feedstock composition, reaction mechanism formulation and reaction network generation, kinetics and reactor type. The kinetic parameters were obtained by training the experimental data with a global optimization algorithm, and the model calculated values of the fraction yield, gas yield, and hydrocarbon composition of the liquid products are in agreement with the experimental data. The model was used to analyze the molecular transformation pathway of crude oil to light olefins under the optimal experimental conditions, and the effects of the theoretical key cracking main reaction and side reaction on the light olefin yield were quantitatively compared. The product distribution under ideal conditions after eliminating the side reaction was explored. Model calculations revealed that the three most critical cracking primary reaction paths affecting light olefins are: olefin middle cracking, olefin cracking to propylene or butene, and paraffin middle cracking, the three main side reactions affecting light olefins are: hydrogen transfer, olefin cyclization and olefin polymerization. Using the model to calculate the optimal experimental point, simulation optimization after elimination of all side reactions, the ethylene, propylene and butene yields were increased by 3.91, 10.88 and 10.51 percentage points, respectively, the total light olefin yield can be relatively increased by about 45.5% (mass fraction).

The separation of olefin/alkane in naphtha is the requirement of feedstock optimization and product purification in petrochemical processes, and liquid-liquid extraction is an important olefin/alkane separation method. This study investigated the feasibility of bimetallic ionic liquids for highly selective extraction of olefins using 1-hexene/n-hexane as a model hydrocarbon mixture. The results showed that the aluminum-copper bimetallic ionic liquid had good separation performance for 1-hexene/n-hexane. Under the conditions of a solvent-oil mass ratio of 2 and an extraction temperature of 10℃, the 1-hexene extraction selectivity is 6.33, which is better than conventional imidazole-type ionic liquids and traditional organic solvents. The aluminum-copper bimetallic ionic liquid had good reusability. The anionic structure of the bimetallic ionic liquid was revealed by synchrotron X-ray absorption fine structure spectroscopy (XAFS) and density functional theory (DFT). The interaction of the ionic liquid with 1-hexene and n-hexane was further analyzed by using quantum chemistry software to explain the selective separation of 1-hexene by the bimetallic ionic liquid.

The depressurization separation process of the mixture of high-pressure polyethylene and supercritical ethylene involves complex two-phase flow and phase change mass transfer process between supercritical ethylene and polydisperse polyethylene. The existing models not only lack effective data verification, but also do not have the ability to accurately predict the molecular weight distribution of polydisperse polyethylene wax. Therefore, this paper first characterizes the molecular chain structure of high-pressure polyethylene and its polyethylene wax. Then, based on the separation mechanism, a modeling strategy for predicting the flow rate and molecular weight distribution of polyethylene wax at the gas phase outlet of the high-pressure separator is proposed. Finally, the effect of operating conditions on the yield of polyethylene wax is studied. The research methodology and results will not only provide theoretical guidance for optimizing the high-pressure polyethylene separation process and the targeted regulation of the wax content in the product, but also can be extended to the polymer separation process of other solution polymerization processes, which is of great significance.

Nitrogen trifluoride plays a critical role in the etching and cleaning processes in integrated circuit fabrication.Its product purity and purity stability are high, and the energy consumption is high. Focusing on the energy efficiency and controllability of the nitrogen trifluoride distillation process, the separation sequences, thermal integration, and dynamic control of the process were systematically studied. Based on the existing industrial direct separation sequence process, the indirect separation sequence process, the heat-integrated direct separation sequence process, and the heat-integrated indirect separation sequence process were proposed. Simulation results indicate that the heat-integrated indirect separation sequence process is optimal, reducing the total annual cost by 96.4×10⁴ CNY compared to the direct separation sequence process with an annual capacity of 120000 kmol. A dynamic control structure study for the direct separation sequence process and the heat-integrated indirect separation sequence process was conducted. The results show that the proposed control structures exhibit excellent control performance for disturbances in feed flow and composition. The findings provide reference on energy-saving and control strategies for the industrial nitrogen trifluoride distillation process.

Ammonia separation and recovery are widely used in industry, but traditional ammonia separation methods are often accompanied by high energy consumption. Pressure swing adsorption (PSA) technology, as a gas separation method with low energy consumption, simple equipment and flexible operation, has been widely used in the field of gas separation. At present, there is a lack of extensive analysis and research on the ammonia separation process of pressure swing adsorption. Based on this, this paper takes the simplified synthetic ammonia reactor-off gas as the research object, and uses a high silica-aluminium ratio molecular sieve HS-1 made in the laboratory as the adsorbent, and determines the adsorption data of three gases, NH₃, N₂ and H₂, on this adsorbent, which provides the relevant parameters for the simulation. A two-bed vacuum pressure swing adsorption (VPSA) process was proposed, the numerical simulation method was used to study the pressure swing adsorption process for ammonia separation of the ammonia synthesis reactor tail gas. In addition, the performance of process separation under different operating conditions is studied to investigate the effect of operating parameters on process performance. The simulation results show that under the conditions of adsorption pressure of 5 bar (1 bar = 10⁵ Pa), adsorption time of 250 s, and feed amount of 1.2 mol·min^-1, the purity of NH₃ separated by this process can reach 89.30%, the recovery rate can reach 94.67%, and the separation energy consumption is 38.02 kJ·mol^-1.

Cyclohexene is an important chemical raw material, and the partial hydrogenation of benzene is a primary method of production. However, the process generates unconverted benzene and cyclohexane as a by-product. The distillation of cyclohexene consumes a lot of energy. This study explores the potential for energy savings in the distillation processes of benzene, cyclohexane, and cyclohexene. Aspen Plus simulation was employed to optimize and compare the economic viability of a four-column industrial extractive distillation process (FC) and a three-column extractive distillation process (TC), identifying the three-column process as more efficient. Based on the TC process, the heat integrated process (TH), heat pump assisted heat integrated process (THP), dividing wall tower-benzene tower process (EC1), cyclohexane tower-dividing wall tower process (EC2), heat pump assisted dividing wall tower-benzene tower process (EHP1) and heat pump assisted cyclohexane tower-dividing wall tower process (EHP2) were proposed. The results indicate that the heat pump-assisted cyclohexane column-dividing wall column process is the most optimal, achieving reductions in annual total cost, energy consumption, and CO₂ emissions by 21.1%, 32.6%, and 31.7%, respectively, compared to the three-column extractive distillation process.

Carbon capture, utilization, and storage technology is a key technology for addressing global climate change, and flue gas from thermal power plants is one of the main sources of industrial carbon emissions. The pressure swing adsorption process is one of the commonly used flue gas carbon capture processes. Existing studies have shown that conventional vacuum pressure swing adsorption is difficult to obtain carbon dioxide products that meet the indicators. Double reflux pressure swing adsorption can obtain two products with high purity and recovery rate, but the production capacity is low. For this purpose, using silica gel as the adsorbent, a simulation study was conducted on a two-stage process coupling the dual reflux pressure adsorption process and conventional vacuum pressure swing adsorption process for flue gas with a feed composition of N₂/CO₂=85%/15% based on literature data. The effects of feed position, adsorption time, gas velocity, light component reflux rate, and heavy component reflux rate on performance were explored. The results showed that when the adsorption pressure was 200 kPa for the first stage and 105 kPa for the second stage, the desorption pressure was 30 kPa for the first stage and 2 kPa for the second stage, the feed position was 0.4 times higher than the bottom, the adsorption time was 90 s, the gas velocity was 0.07 m/s, the reflux flow rate of light components is 5.5×10^-3 mol/s and the reflux flow rate of heavy components is 1.1×10^-2 mol/s, 96.42% CO₂ and 99.93% N₂ can be obtained, with recovery rates of 96.22% and 99.47%, respectively. In addition, compared with existing research results in the literature, the proposed two-stage process has high productivity and low energy consumption.

Batch distillation is an important chemical separation technology that has significant advantages in processing small batches and multi-component production. To enhance the performance of batch distillation, researchers have proposed various batch distillation intensification structures, such as middle vessel batch distillation column (MVBDC) and dividing wall batch distillation column (DWBDC). This paper establishes dynamic simulation models for three typical structures: conventional batch distillation column (BDC), MVBDC, and DWBDC. It also establishes control systems and strictly optimizes the operational variables of the three batch distillation processes using Bayesian optimization algorithms. The results of strict optimization are compared in order to evaluate the advantages and disadvantages of these three structures. The findings indicate that the DWBDC has the shortest operating time and the best economic benefits, making it a superior batch distillation structure.

In complex industrial production process, it is very important to establish an accurate evaluation model of industrial running state performance grade in order to improve product quality and production efficiency. In recent years, deep learning techniques have made some progress in this area. However, unbalanced data samples are often encountered in the actual industrial production process, and the existing deep learning performance evaluation methods have poor ability to mine valuable feature information in a limited number of samples, resulting in low performance evaluation accuracy. To this end, this paper designs a generative adversarial network based on weighted adaptive feature fusion network of double variational autoencoder (DVAE-WAFFN-GAN) to enhance samples of fewer categories and improve the accuracy of performance evaluation. This method combines VAE and GAN networks. First, sparse data are used to pre-train the convolutional variational autoencoder (CNN-VAE) and the long short-term memory variational autoencoder (LSTM-VAE) to extract temporal and spatial characteristics of real data. When training the generated network, the random noise is first input into the two pre-trained decoders, and the decoder outputs the encoded feature vector of the real sample. Then, the WAFFN is designed using the attention mechanism to give different weights to the feature vectors output by the two variational autoencoder decoders for fusion. The fused feature vectors are used to replace the random noise in the original GAN to generate data, so as to improve the quality of data generated by the generator and improve the accuracy of performance evaluation. Finally, the method is simulated on the unbalanced industrial data set.

A composite hydrogel was prepared by copolymerization of zwitterionic betaine methacrylate sulfonate (SBMA) with acrylic acid (AAc) and addition of fumed SiO₂ nanoparticles, P(SBMA-co-AAc)/SiO₂, in which both the chemical crosslinking and physical crosslinking coexist. The addition of SiO₂ particles effectively reduces the relative swelling degree of the hydrogel in water and seawater, and significantly improves the tensile strength and modulus of the hydrogel. The tensile strength and Young's modulus in seawater can reach 662 kPa and 429 kPa, respectively, and the compressive modulus is 225 kPa. At the same time, it has high elongation at break. The hydrogel coating has excellent drag reduction effect and exhibits a low friction coefficient under high sliding speed. The friction coefficient with the glass surface can be as low as 0.004 under a load of 1 N. The composite hydrogel also shows excellent anti-protein adsorption and antibacterial properties. The hydrogel coating could be adhered on the surface of tinplate sheet with high adhesion energy. P(SBMA-co-AAc)/SiO₂ composite hydrogel has simple preparation process and low cost, which provides a reference for the application of antifouling and drag-reducing hydrogel coating.

As a green solvent, organic superbase proton-type ionic liquids show unique advantages in the field of CO₂ capture. In this work, we investigated the organic super base dual-cation protic ionic liquid [DBUH]₂[NtBuDEA], synthesized via the reaction between 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and N-tert-butyl-diethanolamine (NtBuDEA). The microstructure, action mechanism and absorption process between the [DBUH]₂[NtBuDEA] and CO₂ were analyzed by density functional theory (DFT) and molecular dynamics (MD) simulation. The results demonstrated that the anion [NtBuDEA]^2- is critical for CO₂ absorption, engaging in chemical bonding with CO₂ to form the alkyl carbonate [NtBuDEACOO]^2-. Additionally, CO₂ molecules diffuse rapidly from the gas phase to the surface of absorbent and accumulate at the gas/absorbent interface. The amount of absorbed CO₂ fluctuates around the average value after reaching maximum absorption. Temperature and pressure are key factors influencing CO₂ uptake and it is favorable for CO₂ capture through decreasing the reaction temperature and increasing the CO₂ partial pressure. Although the existence of water reduces the interaction energy between the absorbent and CO₂, it enhances CO₂ transfer performance, particularly under high pressure conditions, where the CO₂ absorption capacity per molar ionic liquid in water-containing ionic liquids surpasses that in pure ionic liquids.

Hydrotreating is a crucial process for upgrading low-quality heavy oils. However, the presence of asphaltene supramolecules severely impedes the efficiency of hydrogenation. Therefore, it is very important to improve the hydrogenation decomposition efficiency of asphaltene supramolecular in three main hierarchical structures (molecular unit, nanoaggregate and cluster). This study investigated the reaction performance of direct hydrogenation of crude oil and the change law of asphaltene supramolecular hierarchical structure, aiming to provide a new solution for improving the asphaltene supramolecular decomposition efficiency in petroleum. The results indicate that direct crude oil hydrogenation performs better in upgrading than heavy oil hydrogenation, achieving a removal rate of over 70% for non-hydrocarbon components and more than 80% for asphaltenes. During the crude oil hydrogenation, the apparent structural size of asphaltene decreased from a range of 2—4 μm to below 2 μm, resulting in a more uniform particle size. The hierarchical structure of asphaltene supramolecules has changed significantly. The size of supramolecular clusters has decreased by over 50% compared to their size before hydrogenation. Additionally, nearly 90% of the amorphous nanoaggregates in asphaltene supramolecular structures have been converted, and the conversion of difficult-to-convert crystalline nanoaggregates has exceeded 70%. Hydrogenating crude oils decrease the spatial shielding effect among molecular units, resulting in a more compact secondary structure. This study investigated a novel method for the direct hydrogenation of crude oils, aiming to enhance the dissociation of asphaltene supramolecules and facilitate the efficient conversion of low-quality crude oils.

Hydrogen energy is one of the most promising clean energy sources. Green hydrogen production can be achieved by electrolyzing water from renewable energy sources, but the efficient storage and transportation conditions of hydrogen are difficult. Ammonia is an efficient hydrogen storage material, but the high temperature and high pressure reaction conditions required for ammonia synthesis lead to high energy consumption. Therefore, the process development of hydrogen production from renewable energy electrolytic water - low temperature and low pressure ammonia synthesis is of great significance for green transformation of energy and low-carbon development of company. Based on Aspen Plus process simulation software, this study designed and developed a process of hydrogen production from renewable energy electrolytic water - low temperature and low pressure ammonia synthesis. Combined with the production conditions of synthetic ammonia industrial demonstration enterprise, a 10000 t synthetic ammonia demonstration production process was reasonably designed. The photovoltaic power generation combined with network electricity was used to supply energy for the alkaline electrolytic water to produce hydrogen, and 1000 m³/h (standard condition) hydrogen with the purity of 99.999% was produced at 85℃ and 1.6 MPa. In order to meet the demand for 10000 t synthetic ammonia, further combined with the existing nitrogen and hydrogen-nitrogen mixture of the industrial demonstration enterprises, the reaction of ammonia synthesis was carried out at 400℃ and 7 MPa, and the liquid ammonia product with a purity of 99.9% was obtained by ammonia cold separation. In addition, the high energy consumption synthetic ammonia process is designed with four heat exchangers to save energy. This study can provide a reference for the industrial demonstration of low temperature and low pressure ammonia synthesis with hydrogen production from renewable energy electrolytic water.

The combustion of ammonia faces problems such as high nitrogen oxide emissions and poor combustion stability, and the concept of staged combustion is one of the ways to solve these problems. However, the complex combustion characteristics are still unclear. Experimental measurements and large eddy simulations were conducted on an in house designed axially air-staged turbulent combustion device. The fuel gas is mixture of NH₃ and CH₄ fuel, and the equivalence ratio of the primary stage maintained at 1.2, with the overall equivalence ratio between 0.4 and 0.9. The variation characteristics of nitric oxide (NO) with the total equivalence ratio were obtained through experimental measurements. Large eddy simulation combined with dynamic flame thickening model was used to perform detailed calculation and analysis of three combustion cases, and the calculated results were in good agreement with experimental data. The study revealed that NO emissions increased as the overall equivalence ratio decreased. Two combustion modes were observed within the combustion chamber: a rich-premixed golden flame of ammonia-containing gas at upstream, and a hydrogen-air diffusion blue flame at downstream. In the first-stage combustion chamber, NO emissions are mainly affected by OH, while NO generation in the second-stage combustion chamber is less affected by OH.

Petroleum asphalt has the advantages of low price, high aromaticity and easy polycondensation, and is an ideal precursor for the preparation of high-additive hard carbon anode materials. However, the aromatic hydrocarbons and alkane in petroleum asphalt are prone to condensation and rearrangement during its direct carbonization, and resulting in high graphitization, small layer spacing coupled with few defect sites, which lead to a poor sodium-ion storage performance. Therefore, this work proposes to introduce NaCl pro-oxygenic agent into the asphalt pre-oxidation process for promoting oxidative cross-linking reaction, inhibiting the rearrangement of the asphalt molecular structure, which can reduce the graphitization degree of hard carbon, expand the layer spacing, and introduce abundant CO groups and closed-pore structures, thereby enhancing the sodium-ion storage performance of the pitch-based hard carbon anode. This asphalt-based hard carbon anode delivers high specific capacities of 285.0 and 145.0 mAh·g^-1 at 30 and 300 mA·g^-1, respectively, coupled with 96.3% initial coulombic efficiency. Meanwhile, it has a high plateau capacity of 173.2 mAh·g^-1 at 30 mA·g^-1, corresponding to 61.4% of the total specific capacity. In addition, the capacity retention rate of this anode is as high as 93.94% for 200 cycles at 0.1 A·g^-1, demonstrating an excellent cycling stability performance.

Using renewable resources to prepare new bio-based polymers can reduce dependence on fossil resources and is an effective means to alleviate the energy and environmental crisis. This work reported a series of fully bio-based poly(butylene succinate/\mathrm{2,5}-furandicarboxylate) (PBSF) synthesized by one-pot melt polycondensation using 2,5-furandicarboxylic acid (FDCA), succinic acid (SA) and 1,4-butanediol (1,4-BD) as the comonomers and titanium (Ⅳ) butoxide as the catalyst. The effects of the chemical structures and compositions of the PBSF copolyesters on their thermal behavior, crystalline behavior, thermal stability, mechanical properties, gas barrier properties and hydrophilicity were systematically investigated. The results showed that as the FDCA molar content increased from 25% to 100%, the glass transition temperature (T_g) of the copolyester increased from -23.6℃ to 38.6℃, the Young's modulus decreased and then increased, the elongation at break increased and then decreased, the oxygen barrier property decreased and then increased, and the hydrophilicity increased and then decreased. When the molar ratio of FDCA to SA was 44∶56, the copolyester shows typical thermoplastic elastomer characteristics with low T_g value, high elongation at break and without yield point. It is expected that the results can provide valuable guide for the development of high-performance furan-based polyester.

Supercritical CO₂ was used to assist the preparation of biodegradable poly (butylene adipate terephthalate) (PBAT)/polylactic acid (PLA) shape memory foaming materials. The impacts of PLA content on CO₂ solubility and desorption behavior, melting and crystallization, rheological behavior, and foaming behavior of PBAT/PLA composites were studied. The impacts of PLA content on shape memory properties and mechanical properties of PBAT/PLA foams were also studied. The results show that PBAT is conducive to the local movement of PLA molecular segments and promotes the cold crystallization process of PLA. Under low-frequency shear, as PLA content increased, the complex viscosity of PBAT/PLA increased. The diffusion coefficient of CO₂ was fitted from Fick diffusion law. PLA reduced the diffusion coefficient of CO₂ in PBAT/PLA composites during the desorption process, improved the rigidity of the foams and played an anti-shrinkage role. At the PLA content of 20% (mass), PBAT/PLA composite obtained a maximum stabilized expansion ratio of 20.5. PLA was crucial for enhancing the shape fixing ratio of PBAT/PLA foams, while it was unfavorable to the shape recovery ratio. When PLA content was 20% (mass), PBAT/PLA foam had the great comprehensive performance with an expansion ratio of 7.5, a shape fixing ratio of 86.8% and a shape recovery ratio of 94.3%. Additionally, when PLA content was below 20% (mass), the tensile/compressive modulus and strength of PBAT/PLA foams increased with the increase of PLA content.

Foaming materials with gradient structure are widely studied due to their innovative structural design and potential multifunctionality. In this work, thermoplastic polyurethane (TPU) was used as the research object. High-ratio TPU foaming materials with gradient cell structure were prepared by primary temperature rising foaming and secondary depressurization foaming, and the influence mechanism of foaming conditions was explored. Microscopic morphology characterization showed that when the foaming time is relatively short, gradient foaming materials with larger cell sizes on both sides and smaller cell sizes in the middle can be prepared due to the temperature gradient existing in the polymer matrix. As the foaming time is prolonged, uniform foaming materials would be prepared due to the reduction of temperature difference. The mechanical properties of TPU foaming materials are tested. The results show that the energy loss coefficient of the gradient foaming materials is slightly higher compared with the uniform foaming materials. However, the relative difference between the two decreases with the increase in foaming expansion ratio. Moreover, the gradient foaming materials have lower hardness and higher resilience rate, demonstrating excellent cushioning performance and resilience at high foaming expansion ratios. This paper provides theoretical basis and practical guidance for optimizing the preparation process of TPU foaming materials and is of great significance for the realization of high-performance and lightweight development of TPU.