Chemical looping technology demonstrates significant potential for enhancing chemical production processes compared to traditional processes, resulting in increased exergy efficiency and reduced carbon emissions. This review focuses on common chemical looping processes for chemical production, including chemical looping reforming/partial oxidation (CLR/CLPO) of methane for syngas and hydrogen production, light alkanes chemical looping oxidative dehydrogenation (CL-ODH) or chemical looping selective hydrogen combustion (CL-SHC) for olefin production, chemical looping oxidation coupling of methane (CL-OCM) for ethylene production, chemical looping dehydrogenation aromatization (CL-DHA) of methane for benzene production, and chemical looping selective oxidation (CL-SO) for oxygen-containing organic compound production (such as methanol, ethylene oxide, and formic acid). A fundamental understanding of the structure-activity relationship between the textual properties of oxygen carriers and chemical looping reaction performance is paramount for achieving the rational design of oxygen carriers. At present, we have a solid theoretical foundation in the design of oxygen carriers. We use the thermodynamic equilibrium oxygen partial pressure of oxides to screen the active components of oxygen carriers, and from controlling the lattice oxygen release kinetics based on surface engineering strategies to in-depth analysis of oxygen carrier performance enhancement strategies through the rational construction of structural and electronic descriptors. Experimental and density functional theory (DFT) computational data-driven interpretable machine learning (ML) can enable high-throughput screening of oxygen carriers, which greatly broadens the screening range and reduces the cost of experiment time. With the development of chemical looping technology, the concept of oxygen carrier can be further extended to looping material (LM), such as nitrogen and chloride carriers. Photo/electro-driven chemical looping processes provide new routes to synthesize high-value-added products at low temperatures or even room temperatures, thereby broadening the application scope of chemical looping technology. Additionally, chemical looping technology can be applied to enhance the separation process of binary azeotropic organic mixtures, which is of great significance for developing low-cost, low-pollution, and low-emission separation processes.

The phenomenon of asphaltene association and aggregation in petroleum has an important impact on the exploitation, upgrading, storage and transportation of petroleum (especially unconventional petroleum ores such as heavy oil or tight oil reservoirs). The aggregation of asphaltene molecules directly determines the physical and interfacial properties of crude oil, which is the main cause of adsorption and deposition of petroleum components on the surface of minerals or pipeline walls, emulsification of oil and water (solid), and high viscosity of crude oil. This article systematically reviews the phenomenon and theoretical development of intermolecular association of asphaltene, explores the mechanism of asphaltene molecular association and aggregation from the perspective of non covalent interactions between molecules, and elaborates on the decisive influence of non covalent interactions dominated by electrostatic and dispersion on asphaltene association and aggregation. On this basis, the current status and development direction of the application of theoretical computation and interfacial characterization techniques on the study of asphaltene interfacial phenomena are summarized. Finally, based on the theory and phenomenon of asphaltene molecular association, the application of asphaltene association in the fields of solid surface adsorption and desorption, precipitation and dispersion, emulsion breaking technology development and viscosity reduction technology development has been discussed.

Microchannel evaporators are widely used in refrigeration systems due to low charge capacity, high heat transfer performance, and low cost. Further improvement in the performance of microchannel evaporators helps to reduce refrigerant charge and increase the compactness of microchannel heat exchangers. The microchannel evaporator is mainly composed of a header and microchannel flat tubes. Optimizing the distribution of two-phase refrigerant in the header and enhancing the flow boiling inside the microchannel flat tubes can effectively improve the overall performance of the microchannel evaporator. First, the factors affecting the two-phase distribution in the header and the flow boiling characteristics in the microchannel flat tube were clarified. Then, measures to improve the two-phase refrigerant distribution scheme and enhance flow boiling are summarized. Finally, further prospects are given for methods to improve the performance of microchannel evaporators.

With the help of molecular dynamics (MD) method, 9 systems including AAA-1 asphalt molecular model, 4 bio-asphalt models with different waste wood oil (WWO) modifier content and their corresponding 4 WWO molecular models were constructed. The validity of the above model was verified, and the influence mechanism of temperature and modifier dosage on the compatibility between WWO and petroleum asphalt was analyzed based on microscopic indicators. The results show that the cohesive energy density (CED) and solubility parameters of both WWO and petroleum asphalt indicated a downward trend as the temperature rises. The non-bonding and van der Waals interaction energy were more suitable as evaluation indicators for the interaction between WWO and petroleum asphalt. Furthermore, the petroleum asphalt and bio-asphalts showed similar radial distribution function (RDF) peaks at around 1.11 Å, and the peak height decreased slightly due to the addition of WWO. The free volume fraction (FFV) will decrease as the probe radius increases and increase as the temperature increases. After adding WWO, the FFV generally shows a decreasing trend, but under certain conditions there will be a certain degree of increase. Therefore, it is recommended that the mass fraction of the WWO modifier is 10%.

The potassium-boron rich underground brines in Sichuan Basin are important liquid mineral resources. To reveal the enrichment law of boron and potassium in the underground brines and the exploitation of brine resources, the studies on thermodynamic properties and phase equilibria of the underground brines are essential foundation. The ternary system KCl-K₂B₄O₇-H₂O containing boron and potassium is the most important subsystem in this brine. In this work, ion selective electrode is used to measure the cell potential of the cell without liquid junction K-ISE | KCl (m₁), K₂B₄O₇ (m₂) | Cl-ISE. The total ionic strength of the mixed solution is 0.01—1.00 mol·kg^-1, and the ionic strength ratio of K₂B₄O₇y_b is 0.8, 0.6, 0.4, 0.2 and 0, respectively. The mean activity coefficients of KCl in mixed solutions KCl-K₂B₄O₇-H₂O were calculated by using the measured cell potentials and Nernst equation at 318.15 K. Then, multiple linear regression and nonlinear programming were used to determine the single salt parameters {\beta }^{(\mathrm{0})},{\beta }^{(\mathrm{1})}\mathrm{a}\mathrm{n}\mathrm{d}{C}^{\mathrm{\Phi }} of K₂B₄O₇, and the mixed ion interaction parameters {\theta }_{\mathrm{C}\mathrm{l},{\mathrm{B}}_{\mathrm{4}}{\mathrm{O}}_{\mathrm{5}}{(\mathrm{O}\mathrm{H})}_{\mathrm{4}}}and {\psi }_{\mathrm{K},\mathrm{C}\mathrm{l},{\mathrm{B}}_{\mathrm{4}}{\mathrm{O}}_{\mathrm{5}}{(\mathrm{O}\mathrm{H})}_{\mathrm{4}}} in Pitzer model. The fitted parameters of Pitzer model can be used to further calculate the mean activity coefficient of K₂B₄O₇, osmotic coefficient, water activity, and excess Gibbs free energy of the mixed solutions. Furthermore, the phase equilibria of ternary system KCl-K₂B₄O₇-H₂O at 318.15 K are determined experimentally in this work. The results show that the phase diagram of the system contains one invariant point, two solid crystallization regions (KCl and K₂B₄O₇·4H₂O), and two isothermal solubility curves. Using the ion interaction parameters and Pitzer model fitted in this work, the phase equilibrium of the ternary system was theoretically predicted. The predicted results show that the calculated values are in good agreement with the experimental data. The research results provide an important theoretical basis for the development and utilization of boron-potassium resources in the underground brines.

By coupling VOF (volume of fluid) and the overset meshing method, direct numerical simulation of “particle-particle” oblique collisions with surface-attached droplets is carried out, and the evolution law of the liquid bridge, particle motion, and collision restitution coefficient are obtained during the collision process. Under different collision angles, the effect of liquid on the collision restitution coefficient is the most significant for the normal collision. With the increase in liquid viscosity, the normal and total restitution coefficients decrease, while the tangential restitution coefficient slightly increases. With the increase in collision velocity, the normal and total restitution coefficients increase, while the tangential restitution coefficient decreases. Under the oblique collision, the rotation of particles promotes particle separation, and the liquid bridge can generate shear action, converting part of the tangential kinetic energy into normal kinetic energy. This present study can provide basic data for developing a simplified model of wet particle collisions.

To probe into the separation process of coarse and fine particles in the classifiers, based on the particle-eddy interaction model and the discrete element soft sphere model, the influence of turbulent fluctuation in the turbo air classification flow field on particle motion and cut size d₅₀ are investigated. The distribution laws of particles in the classification process are also explored. Turbulent fluctuation mainly influences the trajectory of small particles. It has little effect on the trajectory of large particles, and has no significant effect on cut size d₅₀. At an inlet air velocity of 12 m·s^-1 and a rotor cage rotating speed of 1200 r·min^-1, for the radial distribution, the fine particles less than 20 μm are mainly distributed in the rotor cage area, particles with size near d₅₀ move with swirling flow in the annular region, and the coarse particles larger than 25 μm gather in the area near the guide blade. Due to the interaction between particles, some fine particles may be mixed with the coarse particles,resulting in a “fish-hook effect”. For the axial distribution, the fine particles less than 20 μm are mainly distributed in the classifier near the top area, the coarse particles gradually settle downward and the larger the particle size the faster the settlement.

The condensing flow and heat-transfer characteristics around dentate-fin tubes were investigated using numerical and experimental methods. Using the examined computational model, the film flow characteristics and condensing heat-transfer coefficient of the dentate-fin tubes in the circumferential and axial directions were analyzed. Comprehensive information regarding the condensation process in high-performance tubes was provided. The results showed that the circumferential and axial film thicknesses of the dentate-fin tubes increased with increasing fin density. The liquid film distribution of dentate-fin tubes with a low fin density was relatively uniform, and condensate drainage was easy. The special heat-transfer structure of dentate-fin tubes was examined, and it was found that the complex heat-transfer structure led to variations in the surface tension, which changes the liquid-film distribution. The local condensing heat-transfer coefficient of the dentate-fin tubes was very sensitive to the liquid-film distribution. The optimal fin density corresponding to the maximum total heat-transfer coefficient was obtained, indicating that the enhanced heat transfer mechanism of dentate-fin tubes is the combined effect of heat transfer area and liquid film thickness.

Active reinforcement technology is an effective means to improve the efficiency of heat collectors. This study systematically investigated the effects of irradiation intensity, nanofluid concentration, rotor speed, number and arrangement of rotors, rotor color and type on the heat collection performance of water-based carbon black nanofluids under the action of swirling flow using a tubular active enhanced heat collection device. The results show that the photothermal conversion efficiency significantly increases with the increase of irradiation intensity. The addition of carbon black collagen protein increased the full range photothermal conversion efficiency of the medium by 56.6% to 216.7% during the same time period. The water-based carbon black nanofluid with a mass fraction of 0.005% had the highest photothermal conversion efficiency and higher energy efficiency ratio. At a rotor speed of 150 r/min, the full range photothermal conversion efficiency ultimately increased by 30.32%, and further increasing the rotor speed will not increase the heat collection efficiency of the nanofluid. When the rotors are evenly arranged, reducing the number of rotors by half will hardly affect the heat collection efficiency. The combination of rotor color and type has a synergistic effect on the heat collection efficiency of different concentrations of nanoluids. Black low flow resistance rotors have better heat collection effects in pure water and high concentration nanofluids, while the two white blade rotors have better heat collection effects in medium and low concentration nanofluids. This study clarifies the rules that affect the heat collection performance of nanofluid under rotor swirling flow, and provides new ideas for solar photothermal utilization.

Latent heat thermal energy storage using phase change materials is an effective approach to address the intermittency issues of renewable energy sources. Nano-scale phase change microcapsules were prepared by interfacial hydrolysis condensation method using tetrabutyl titanate (TBT) as the precursor. The average thermal conductivity is enhanced to 215%, reaching approximately 0.43 W/(m·K). The phase change temperature is found to be 42.4℃. The latent heat of nano-encapsulated phase change materials is about 234.7 J/g. The nano-scale phase change microcapsules improved heat transfer performance and are suitable for heat storage of solar thermal water heating systems. A three-dimensional computational model was established, and numerical simulations were conducted on the packed bed using Fluent software to study the heat storage/release performance of the sequential structure (SS) and cross compound structure (CS) packed bed. The analysis focused on examining the variations in liquid fraction, temperature distribution, and thermal storage/release power for both SS and CS under different flow rate. The results show that the melting/solidification rates increase with increasing flow rate. At the same flow rate, CS exhibited faster melting/solidification compared to SS. The temperature variation of CS was more uniform than that of SS at different stages. At lower flow rate (2 L/min), both SS and CS exhibit longer and more stable periods of thermal storage/release. Under different flow rate (2, 4, and 6 L/min), the peak thermal storage power of CS is 1.7—1.9 times that of SS, and peak thermal release power is 1.8—2.0 times that of SS.

In order to study the scale-resisting properties and scale-resisting mechanism of spirals inserted in tubes, the effects of three spirals inserted into heat exchange tubes at different flow rates on fouling thermal resistance and total heat transfer coefficient were experimentally studied. Meanwhile, the particle size and porosity of fouling were quantitatively characterized from a microscopic perspective to obtain the microstructure distribution of fouling. The results show that, under the experimental conditions, with the increase of flow velocity, the fouling resistance of the interpolation spiral decreases by 63%, the heat transfer coefficient decreases by more than 20%, and the interpolation spiral with a pitch of 20 mm has the best scaling performance. The particle size and porosity of dirt gradually increase from the near wall area to the surface area, and there is a clear crystal transition feature between the dirt layers. The porosity of the surface area and transition area of the fouling layer increases with the increase of flow velocity, and the change of the internal structure of the fouling by the characteristics of the interpolation spiral flow field is the fundamental reason for the difference in scale-resisting properties.

The rising behavior of bubbles in different liquid media (deionized water, ionized water, 5# white oil and water-white oil solution) was observed by using high-speed photography. Three air-injection nozzles with different outlet diameters were employed. A comprehensive comparison of the rising velocity, equivalent diameter, aspect ratio, and drag coefficient of bubbles obtained under different operating conditions was implemented. The results demonstrated that the trajectory and kinetic characteristics of the bubble varied considerably in different single mediums. The viscosity and surface tension of the medium exerted a significant effect on shape and size of the bubble. Additionally, behavior of the bubble passing through the water-white oil interface was investigated. It was observed that when the bubble was away from the interface, its motion resembled that observed in corresponding single medium. However, when the bubble crossed the interface, it was enveloped by a liquid film, which subsequently detached from the bubble. After passing through the water-white oil interface, small-sized bubbles exhibited the geometric and kinetic characteristics similar to those in single white oil. In contrast, large-sized bubbles were characterized by a zigzag trajectory after passing through the water-white oil interface. Meanwhile, the bubble aspect ratio varied considerably.

Biomass chemical looping pyrolysis (BCLPy) employs oxygen carriers to decompose the pyrolysis-gasification reaction of biomass into a two-stage reaction at different temperatures, yielding simultaneously both high quality bio-oils/chemicals and clean syngas. In this work, six iron-based composite oxygen carriers were prepared by sol-gel method by adopting alkali earth metals such as Ca, Sr, Ba and transition metals such as Co, Ni, Cu, respectively. The oxygen-carrying and catalytic properties of six iron-based oxygen carriers during chemical looing pyrolysis of corn stalk were studied. The results show that six iron-based composite oxygen carriers have excellent catalytic cracking, ketonization and hydrodeoxygenation ability for liquid products during biomass pyrolysis stage, significantly reducing the content of oxygen compounds in bio-oils and increasing the generation of hydrocarbon compounds. At the gasification stage, oxidize pyrolytic char can be oxidized to syngas with CO as main components. Among them, the Ca-Fe composite oxygen carrier reduces the content of acid compounds from 29.4% without oxygen carrier to 0.3%, and the CO yield in syngas reaches 330 L/kg biomass. Under the optimal condition of 650℃ and the mass ratio of biomass to oxygen carrier 3∶6, ten pyrolysis-gasification cycles were investigated by using Ca-Fe composite oxygen carrier. The results indicate that the Ca-Fe composite oxygen carrier exhibits excellent catalytic, deoxygenation and oxidation properties, however, phase separation and agglomeration of iron was observed during the 10 cycles. It is imperative to focus on the development of iron composite oxygen carrier with enhanced reactivity and a stable structure in the future research of biomass chemical looping pyrolysis.

A hydrothermal method was used to synthesize ZSM-22 molecular sieve and prepare a catalyst carrier. By loading precious metal Pt, a highly dispersed Pt/H-ZSM-22 hydroisomerization catalyst was prepared. Using n-C₁₂ as feedstock, the hydroisomerization performance of the catalyst was investigated. By introducing a certain amount of nitrogen-containing species in the reaction process, the acid of catalyst was adjusted in the hydroisomerization reactor, and the change of the catalyst performance was investigated. The results showed that, as the reaction temperature increased, the liquid yield of Pt/N-ZSM-22 decreased slowly, and the isomerization selectivity of Pt/N-ZSM-22 were about 3 percentage points higher than Pt/H-ZSM-22 under the same conversion rate above 85%. The acid sites of Pt/N-ZSM-22 catalyst which was absorbed by the nitrogen-containing species can also be restored during raising the reaction temperature. The catalyst after acid regulation was used for hydroisomerization of the hydrocracking UCO, and the base oil yield was significantly higher than the catalyst before regulation.

Trans-TXA, as the main active component in the isomers of tranexamic acid, has coagulation function and is widely used in the pharmaceutical industry. Its synthesis is mainly achieved through isomerization of cis-TXA. In the actual industrial production process, it involves kilogram level synthesis. Therefore, the most commonly used method is to use tranexamic acid as raw material to obtain a mixture of cis-tranexamic acid and trans-tranexamic acid through catalytic hydrogenation. Then, cis-tranexamic acid is converted to trans-tranexamic acid by isomerization reaction. The reaction conditions of cis-tranexamic acid isomerization are harsh, requiring high temperature, high pressure, and the participation of noble metal catalysts. By consulting the literature at home and abroad, it was found that some preparation studies are conditional experiments, however, there are few reports on the kinetics of the reaction system. How to obtain the isomerization reaction kinetic data and provide reliable data for industrial production design has become the focus of research. The purpose of this work is to determine the reaction mechanism and kinetics of tranexamic acid isomerization reaction under alkaline conditions. This study uses first principles simulation to obtain theoretical data such as the enthalpy change of isomerization raction, Gibbs free energy, and structural changes in the reaction process. The simulation results show that the data obtained by different calculation methods are different. Among them, the Gibbs free energy and reaction enthalpy data calculated by GGA+PBE method were the largest (ΔH_r =14.5 kJ∙mol^-1, ΔG_r =16.0 kJ∙mol^-1), and the minimum (ΔH_r=11.2 kJ∙mol^-1, ΔG_r=10.7 kJ∙mol^-1) was calculated by GGA+BLYP method. In addition, the reaction barrier is calculated by the transition state search to be 46.86 kJ∙mol^-1. Then, under the actual situation of experimental investigation, the reaction process of cis-TXA isomerization into trans-TXA at 453.15—513.15 K, the reaction kinetic model was established, and the reaction kinetic parameters were obtained. The positive reaction activation energy was 64.9 kJ∙mol^-1, the pre-exponential factor was 2.15×10⁵ s^-1, the reverse reaction activation energy was 53.8 kJ∙mol^-1, the pre-exponential factor was 4.72×10³ s^-1, and the reaction enthalpy value was 10.4 kJ∙mol^-1 and 11.0 kJ∙mol^-1. The average reaction enthalpy value of 10.7 kJ∙mol^-1 obtained by experimental calculation is basically consistent with the value of 11.2 kJ∙mol^-1 obtained by the simulation of GGA+BLYP method and the value of 12.1 kJ∙mol^-1 obtained by the simulation of GGA+BLYP method of transition state search. Experimental and simulation data provide theoretical data and basis for the industrial design of the substance.

Caprolactam was prepared by Beckmann rearrangement using a spiral microchannel reactor. Through in-situ solvent vaporization and secondary flow technology, it overcomes the problems of high flow resistance in the microreactor of the high-viscosity reaction system, easy to cause local hot spots, and low production capacity. The effect of reaction temperature, solvent vaporization, helical size, pipe inner diameter, feedstock concentration, and flow rate on the conversion and selectivity of the reaction was investigated. The experimental results showed that the conversion rate could reach 100% and the selectivity was more than 99% with a 2 mm inner diameter spiral pipe, dichloroethane as solvent and an acid-oxime molar ratio at 1.1, a preheating temperature at 80℃, a rearrangement temperature at 90℃, a cyclohexanone oxime solution concentration at 10%—20%(mass), a retention time at 15 s, and a spiral diameter at 20 mm.20.2 g/min capacity for a single tube was realized, which corresponds to 9.7 t/a based on 8000 h per year. The results would provide theoretical guidance in the design and development of high-throughput and high-efficiency microchannel reactors. This study presents a solution for microreactors for highly viscous systems.

Crystalline protein drugs have significant advantages in controllable release of active components and biochemical stability, but the optimization and control of protein crystallization are complex. Based on the combined algorithm of morphological population balance (MPB) model and multi-objective genetic algorithm, multi-objective optimization for the cooling crystallization of hen-egg-white (HEW) lysozyme is investigated with the objectives of uniform crystal size distribution (CSD), certain crystal shape, and maximum product yield. The piece-wise cooling strategy with ten sections is adopted, while the cooling rates linearly vary in each section independently. The Pareto-optimal solutions are the trade-off among three objective functions. It is found that the shape objective and yield objective have similar evolution tendency toward their ideal extremes, while the CSD objective evolves toward the opposite direction. With the increase of product yield for different Pareto-optimal solutions, the cooling rates during the crystallization process generally increase, and the relative supersaturation becomes larger, which is also higher than most common small molecules. Due to the different influences of supersaturation on the growth rates of two normal distances, the final protein crystals for those Pareto-optimal solutions with higher yield also have larger dimensions, and their shapes become more plate-like.

Hydrogen energy, as an important carrier for achieving sustainable development, is of great significance for building a clean, low-carbon, and efficient energy system and achieving the “dual carbon” goals. This article designs a complete process for hydrogen separation, which is simulated and analyzed using software Aspen Plus. By proposing a coupled hydrogen separation system consisting of pressure swing adsorption (PSA), rectisol, and membrane separation, and using software such as Aspen Plus for simulation and analysis, the advantages of various separation technologies were combined. The integration of multiple separation processes has broken the purity bottleneck of single membrane separation, resulting in a product hydrogen concentration of up to 99.67%. In addition, it achieves the enrichment of CO₂ and the recycling of CH₄, reducing the loss of hydrogen production raw materials. The entire system has better separation performance compared to existing single technology, providing new insights and application potential for other gas separation problems.

The production process of corn deep processing to produce fructose has problems of outdated control and lack of refinement in production and processing. However, due to the complexity of the process, it is difficult to establish and optimize mechanism based models. Big data technology offers an effective solution by utilizing a substantial volume of production data to uncover process insights and identify key points. Initially, crucial target variables of this process were selected. Using big data technology, the original production data underwent preprocessing steps such as handling missing values, addressing outliers, noise reduction, and dimensionality reduction. Subsequently, three machine learning models—random forest (RF), extreme gradient boosting (XGBoost), and artificial neural network (ANN) were constructed, all achieving R² values exceeding 0.90. Lastly, the SHAP method is used to explain different machine learning models, validate the credibility of the models, obtain the contribution levels of different features to the prediction results, and integrate the results of explanations from different models. This process generates a ranking of the importance of different points in the production process. Combining this with production experience, a mechanistic analysis is conducted to obtain the final key point table.

Shell and tube heat exchangers are important part of the energy system and are prone to fouling failures in the heat conduction tubes over long periods of operation, resulting in reduced heat transfer efficiency, increased flow resistance, increased energy consumption and reduced system pressure, etc. Fouling failures are often hidden within the equipment, and monitoring through operational data or simulation is often insufficient to sense and predict the equipment status under multiple operating conditions. Digital heat exchanger condition monitoring techniques are relatively lacking. In order to establish a digital twin-driven high-fidelity downscaling model for heat exchangers, a radial basis adaptive model downscaling method based on proper orthogonal decomposition is proposed in this paper. The adaptive sampling algorithm based on physical information collects more effective sample data and establishes a high-fidelity reduced-order model of the heat exchanger by POD-RBF, conducts simulation experiments on fouling faults in heat exchangers, and perceives and predicts fouling in heat exchangers using BP neural networks. The experimental results show that the established adaptive sampling reduced-order model improves the solution efficiency by a factor of 1 compared with the reduced-order model without sampling, and the error is about 4% compared with the full-order model, and the fouling data is quickly generated by the reduced-order model which is more consistent with the physical mechanism, and the prediction error is kept at about 0.0554 mm, which can effectively sense and predict the heat exchanger fouling.

Distillation and absorption, as typical nonlinear processes, have a large number of state variables that describe the characteristics of the system during their operation. In order to reconstruct and predict these state variables and realize the real-time digital twin of the distillation and absorption process, this paper obtains an approximate linearized model of the nonlinear system by the dynamic mode decomposition method (DMD), which is used to quickly obtain the state variables such as concentration, flow rate, temperature and holding capacity at each tray of the distillation and absorption process. Based on this, a Kalman filter is applied to correct the linear model generated by DMD in real time, which makes it possible to predict the state variables of absorption or distillation effectively without retraining the model even under off-design and limited measurement conditions.

In order to study the performance of upstream pumping mechanical seal under high-pressure conditions, a thermal elasto-hydrodynamic lubrication model (TEHD) was established considering the fluid-solid thermal coupling between the sealing ring and the lubricating film. Based on the finite element method, the liquid film lubrication equation, the heat conduction equation of the sealing ring and the thermal deformation equation were solved. The triple iteration algorithm was used to obtain the coupling solution between film pressure, film thickness, temperature and deformation of the seal rings. The influence of rotational speed, sealing pressure and medium temperature on the deformation of the end face of the upstream pumping mechanical seal were investigated. And the upstream pumping capacity of the seal under mechanical and thermal deformation were analyzed. The research results indicate that under high pressure conditions, a liquid film gap converges along the upstream pumping direction at the sealing end face, and force deformation under high sealing pressure is the main reason, while thermal deformation partially offsets the impact of pressure deformation. With the increase of rotational speed, the convergence degree of liquid film along the upstream pumping direction decreases, the upstream pumping rate and the friction coefficient increases. With the increase of sealing medium pressure, the convergence degree of liquid film increases, the friction coefficient and the upstream pumping rate decreases greatly. With the increase of the temperature of the sealing medium, the convergence degree of the liquid film and the friction coefficient decreases, and the upstream pumping rate increases. The results can provide a theoretical reference for the structural optimization and design of the upstream pumping mechanical seals for high-pressure conditions.

Chemical looping combustion (CLC) is an important research orientation of clean energy processing and efficient conversion in the period of profound global changes. The reaction between solid fuels such as coal and oxygen carriers are one of the core scientific issues in CLC research. However, the evolution rules and the transformation mechanism are still unclear, especially the microscale description of the molecular structure evolution and functional group transformation of coal and other macromolecular solids in the fuel reactor from the atomic and molecular scale is lacking. Based on the macromolecular structure of coal and ReaxFF MD simulation, we study the chemical looping combustion process of Ningxia QH and YCW coal and nickel oxide oxygen carrier. Through the CLC process analysis of QH-NiO and YCW-NiO systems, the rules of total energy, total molecular number, product distribution and gas conversion are obtained. Based on the ReaxFF MD simulation process, the dynamic evolution process of coal macromolecular structure in CLC process is directly obtained. As the CLC reaction progresses, the macromolecular structure of coal gradually dissociates due to the breaking of old bonds and the generation of new bonds, resulting in various intermediate products, small molecules such as CO _x and H₂O. The regulation and mechanism of quantity and rate of oxygen release from oxygen carrier during CLC in QH-NiO and YCW-NiO systems are revealed. The results show that compared with QH coal, YCW coal has lower metamorphism and higher reactivity. Therefore, the YCW-NiO system has lower total potential energy, generates more molecular fragments and more non-hydrocarbon gas, which can attribute to the oxygen carrier release lattice oxygen earlier. With the progress of CLC reaction, the oxygen vacancy formed on oxygen carrier surface leads to the migration and release of lattice oxygen in the secondary outer and inner lattice to the surface.

The poor performance of air-cooled fuel cells remains a key issue limiting their commercial application. This study used numerical simulation to investigate the effects of cathode oxygen stoichiometric ratio and hydrogen/air arrangement on the performance of air-cooled fuel cell. The results indicate that when the stoichiometric ratio is low, air-cooled fuel cells cannot meet the heat dissipation needs. Increasing the stoichiometric ratio is beneficial for thermal management of air-cooled fuel cells, improving the membrane water content in the membrane electrode and fuel cell performance. In order to ensure the safe operation of air-cooled fuel cells, it is necessary to maintain the operation of air-cooled fuel cells at medium to high stoichiometric ratio. Compared with the hydrogen/air co-current arrangement, the hydrogen/air counter-current arrangement strategy is affected by the dry hydrogen at the anode inlet. The membrane electrode exhibits a local dehydration state, resulting in a slight reduction in performance.

The inorganic and resource disposal technology of tributyl phosphate (TBP) organic hazardous waste is an important environmental protection demand. Based on the principle of chemical looping combustion (CLC) and the mechanism of alkaline hydrolysis of TBP, a reaction system of alkali-assisted thermal oxidation TBP by Mn₃O₄ was constructed. A process of TBP degradation with simultaneous phosphorus recovery was developed. Under an optimal feed ratio of TBP, NaOH and Mn₃O₄ (1 ml∶6 g∶13 g), the conversion rate of P from TBP to inorganic phase could reach 77.47%, and the non-methane hydrocarbon (NMHC) concentration of gas products was only 27.28 mg/m³, which was lower than the relevant environmental standard limit. Inorganic phosphorus products were separated and recovered by ethanol precipitation. X-Ray diffraction (XRD) analysis showed that the main components of phosphorus-containing products included Na₃PO₄, NaPO₃, Na₂HPO₄ and Na₃PO₄·8H₂O. According to mass spectrometry analysis of TBP degradation intermediates, the possible pathways of TBP degradation and phosphorus migration were proposed. Electron paramagnetic resonance (EPR) analysis revealed that hydroxyl radical (·OH) and superoxide radical (·{\mathrm{O}}_{\mathrm{2}}^{-}) played important roles in promoting the degradation of TBP.

Chemical looping dry reforming of methane (CL-DRM) has the potential as an efficient technology to achieve carbon neutrality in terms of converting CH₄ and CO₂ to various value-added products with the minimal separation requirements. Currently, a major challenge facing this technology is the design and development of oxygen carriers with good reactivity and stability. Herein, the Ba-substituted (La_0.5Sr_0.5)_1-x Ba _x Fe_0.6Co_0.4O₃ perovskite oxides with the anchored nanoparticles as the novel oxygen carriers were synthesized and investigated for the redox performance in the CL-DRM process based on various characterization technologies. It is found that La_0.35Sr_0.35Ba_0.3Fe_0.6Co_0.4O₃ oxygen carrier (x=0.3) increases the amount of oxygen consumed (5.29 mmol·g^-1) and shows a higher oxygen diffusion rate to achieve the CH₄ conversion of 84.3% and syngas yield of 15.23 mmol·g^-1 in the CH₄ reduction step. Meanwhile, the syngas selectivity of 95.8%, the CO selectivity of 70.0% and carbon deposition of 1.36 mmol·g^-1 can be obtained. Analysis of the gas generation rate during methane reduction shows that Ba substitution can optimize the lattice structure of the oxygen carrier, leading to high ion mobility, promoting rapid diffusion of oxygen in the bulk phase, and thus improving CH₄ conversion. Furthermore, the excellent oxygen carrier also exhibits the high structure stability and the stable regeneration ability by CO₂ during the successive redox cycles.

In order to solve the problem that the waste heat generated by biomass aerobic fermentation is difficult to be effectively recovered, with corn straw as the main raw material and using heat exchange method, a 100 L scale fermentation device and heat recovery system were built to recover the apparent heat and latent heat in the compost steam. The electric heating method is used to simulate aerobic fermentation heat production. The waste heat recovery process was optimized from the aspects of fluid flow, equipment insulation, water storage and heat transfer area. The heat production and heat recovery effect of the optimized system were tested. The results indicate that fluid flow rate, water tank insulation, and storage capacity have a significant impact on the heat recovery performance of the system. In the simulated heat production mode, the tank temperature can rise from 17℃ to more than 40℃. Finally, through the intermittent heat recovery method, the balanced heat recovery efficiency of the system reaches more than 57%, and the average heat recovery power reaches more than 274 kJ/h, realizing the efficient recovery of fermentation waste heat.

Using Chinese fir sawdust as research object, wood vinegar was prepared by pyrolysis after hydrothermal pretreatment at 180—280℃. The evolution of Chinese fir sawdust components at different hydrothermal temperatures was analyzed by van Soest method, and the effects of the evolution of Chinese fir sawdust components after hydrothermal pretreatment on the yield, organic components, and physicochemical properties of wood vinegar were investigated by using gas chromatography-mass spectrometry (GC-MS), acidity meter, and other testing methods. The results showed that with the increase of hydrothermal temperature, the content of hemicellulose in hydrothermal sawdust decreased continuously. The cellulose content showed a trend of first increasing and then decreasing. The lignin content gradually increases. With the increase of hydrothermal temperature to 230℃, the contents of phenolic and aldehyde in wood vinegar increased gradually, which was consistent with the change trend of lignin and cellulose content respectively. The content of acid compounds slightly decreased, showing a positive correlation with changes in the total content of hemicellulose and cellulose, which are the main sources of acid compounds. When the hydrothermal temperature is 180—230℃, the massive decomposition of hemicellulose in hydrothermal Chinese fir sawdust leads to an increase in the content of cellulose and lignin, resulting in a higher density and lower pH of wood vinegar, but the yield increases only before 200℃. By optimizing the proportion of three components of Chinese fir sawdust through hydrothermal pretreatment, higher quality wood vinegar can be produced.

To investigate the mechanism of 1-nitropropane (1-NP) initiated n-C₆H₁₄ pyrolysis, molecular dynamics (MD) simulations and synchrotron radiation experiments were used to analyze the pyrolysis process of n-C₆H₁₄ before and after the addition of 1-NP. The SVUV-PIMS technique was used to identify and quantify the resulting pyrolysis products of both n-C₆H₁₄ and n-C₆H₁₄ with the addition of 10% 1-NP. The pyrolysis of n-C₆H₁₄ and 1-NP/n-C₆H₁₄ was simulated at different temperatures using ReaxFF MD simulations, which allowed an in-depth investigation of the effects of temperature and 1-NP addition on the pyrolysis rates, heat sink and product distribution. Based on the simulated species evolution and trajectory information, the reaction pathway of 1-NP initiated n-C₆H₁₄ pyrolysis was explored. The results showed that: the addition of 1-NP to n-C₆H₁₄ significantly increased the production of C₂H₄. The production of C₂H₄ from the pyrolysis of n-C₆H₁₄ with 10% 1-NP added at 2103 K is about 2.2 times that of pure n-C₆H₁₄. The addition of 1-NP improves the heat sink of the fuel and reduces the activation energy of the fuel. The primary pathway of pyrolysis of n-C₆H₁₄ initiated by 1-NP is that 1-NP first cleaves to form NO₂ which then reacts with H to form OH. Secondly, the OH abstracts H from n-C₆H₁₄ to form C₆H₁₃. Finally, C₆H₁₃ is further cleaved to form 1-C₃H₇, 1-C₄H₈, 1-C₅H₁₀ and 2-C₆H₁₂.

Zr-based metal organic framework MOF-808 is used as the carrier and is functionalized with polyethylenimine (PEI) to obtain PEI@M-808 composite material, which is used to selectively capture humid flue gas (10% CO₂ + 90 % N₂ + 10 kPa H₂O). The physicochemical properties of the sorbents are characterized by XRD, FT-IR, SEM, and BET techniques, and the effectiveness of the modification scheme is assessed. The sorption performance of PEI300-30@M-808 at trace CO₂ with moisture is dramatically enhanced due to the abundant amine groups on the surface of PEI@M-808 corresponding to the loading of PEI molecules. The adsorption performance of the composite adsorbent at trace CO₂ concentration is greatly enhanced by the introduction of abundant amine functional groups on the surface of MOF-808 due to the loading of PEI. The PEI300-30@M-808 could trap 0.89 mmol/g at 343 K and 0.1 bar while the MOF-808 manifests sorption capacity of approximately 0.052 mmol/g under the same condition. Furthermore, the sorption selectivity of PEI300-30@M-808 is 5524.65 at 10/90 CO₂/N₂ at 0.1 bar and 343 K, which is about 56 times larger compared to that of MOF-808. Additionally, per gram of PEI300-30@M-808 could react with 1.47 mmol/g at the sorption condition with 5% RH, indicating that the moisture has a positive effect for CO₂ capture with PEI-based materials. After 5 cycles, the CO₂ saturated adsorption capacity of PEI300-30@M-808 can still be maintained at 90.7%. Therefore, the PEI300-30@M-808 feature great potential for trace carbon capture in moist flue gas.

To further study the characteristics of flame propagation and explosion wave properties of hydrogen in confined spaces under low-temperature conditions, an explosion chamber was designed, and its precooling process was undertaken. The experimental chamber was designed as a double-layer structure, and the low-temperature nitrogen gas was adopted as the precooling medium, to ensure the temperature of the premixed low-temperature hydrogen/air mixture can be maintained at the preset experimental condition. Based on the fundamental principles of thermodynamics, the steady thermal analysis approach was adopted, and a mathematical model of the chamber’s precooling process was established. The impacts of insulation layer thickness and chamber wall thickness on the precooling process were discussed, and the influences of precooling medium flow rate on precooling time and medium consumption were explored. The results revealed that, when the insulation layer thickness reached 30 mm, heat load from the environment significantly decreased. Compared with the 10 mm and 5 mm wall thickness conditions, the precooling time at 3 mm is reduced by 70.11% and 39.01% respectively, and the consumption is reduced by 70.12% and 39.00% respectively. Increasing the precooling medium flow rate can effectively shorten the precooling time, but the change in precooling medium consumption is not significant.

In order to reduce the harm caused by polyethylene (PE) dust explosion accidents, a 20-L explosion ball and a self-built dust deflagration flame propagation test system were used to conduct explosion suppression experiments. The suppressive effects of ammonium polyphosphate (APP) are examined by evaluating pressure and flame propagation behavior. A synchronous thermal analyzer assesses APP’s impact on the thermal decomposition of PE dust. The reaction kinetics of PE and a mixture of APP and PE (I=1.0) during the rapid pyrolysis phase were derived employing the Coats-Redfern method. Through an in-depth analysis of explosion overpressure, flame propagation, thermal decomposition, and explosion by-products, it becomes evident that APP confers a synergistic explosion suppression effect on PE dust’s gas and condensed phases. The findings illustrate that APP markedly diminishes PE dust’s maximum explosion pressure P_max, maximum explosion pressure rate of rise (dP/dt)_max, and flame propagation speed. When the inhibition ratio was 1.0, the pressure peak vanished, indicating complete suppression of PE dust. Additionally, pyrolysis characteristics indicated that APP introduction attenuates PE dust’s pyrolysis rate and postpones pyrolysis and oxidation events. Pyrolysis kinetics model analysis showed that PE dust adheres to the A3 model during rapid pyrolysis, while it transitions to the R2 model with APP addition, with corresponding average activation energies of 137.34 kJ/mol and 228.52 kJ/mol. Significantly, APP integration results in a pronounced rise in PE’s apparent activation energy, highlighting the deceleration of PE particles’ oxidative pyrolysis. Employing FTIR analyses, a pronounced reduction in the characteristic —CH₂ and —OH peaks with APP was discerned. It’s elucidated that APP provides synergistic explosion inhibition effects in both the gas and condensed phases, primarily by curtailing free radicals via phosphorus-volatile release during pyrolysis and fostering a porous, dense surface carbon layer to inhibit deflagration. These insights lay the groundwork for the development of superior powder explosion suppressants specific to PE dust.