ABSTRACT To address the issues of neglecting the spatiotemporal correlations among process variables, low‐level features are vulnerable to noise interference, and the gradual loss of key information layer by layer during deep network training in traditional stacked autoencoder‐based soft‐sensor models, this paper proposes a hierarchical complementary enhanced autoencoder integrating spatio‐temporal interaction feature (ST‐HCEAE) model. Firstly, a spatio‐temporal interaction network (STIN) is constructed to extract the global and local spatio‐temporal interaction relationships. Temporal features are captured by using the temporal attention mechanism. The maximum information coefficient (MIC) is adopted to obtain the global spatial interaction relationship across time steps. The gated graph attention (GGAT) mechanism is proposed to obtain the local spatial interaction relationship at each time step, and the spatio‐temporal interaction features are obtained through adaptive fusion. Secondly, the hierarchical complementary enhancement (HCE) module is introduced. By adopting the dynamic fusion strategy of upsampling hierarchical complementary enhancement (HCE‐up) and downsampling hierarchical complementary enhancement (HCE‐down), and leveraging bidirectional information compensation between adjacent hidden layers, the problems of noise interference in the feature extraction process and key information deficiency in deep network training are effectively addressed. Afterwards, multi‐layer features are fused through the gating mechanism to establish a regression prediction model. Finally, two industrial cases, namely the debutanizer tower and sulfur recovery, were adopted for experimental verification. The experimental results show that, compared with the other five existing modeling methods, the proposed ST‐HCEAE method has higher prediction accuracy.

ABSTRACT Aiming at the current demand for using wellbore coaxial lines with tubing and casing in oil wells, implementing microwave chemical‐assisted crude oil upgrading underground, and promoting “carbon‐zero” mining projects in oil field development, we carried out theoretical analysis, simulations, and applied research on the distributed parameters of eccentric coaxial lines. Assuming that the rate of change of the electromagnetic field distribution along the circumference of the coaxial line is small when the eccentricity is small, we derived a formula for calculating the electromagnetic field intensity of the eccentric coaxial line. Using the “field‐circuit combination” method of electromagnetics, we further established theoretical models for the distributed parameters—including inductance, capacitance, resistance, and conductance—and proposed a new calculation approach. The validity and accuracy of the proposed models are verified through comparison with HFSS simulations and previously established empirical formulas. The new theoretical analysis and HFSS software simulation results demonstrate that conventional tubing and casing structures in oil wells can be utilized to construct coaxial lines for microwave energy transmission. However, the eccentricity of the inner conductor significantly influences the electromagnetic field distribution, characteristic impedance, power‐handling capacity, and energy loss. To ensure efficient microwave propagation, the eccentricity should ideally remain below 30% and must not exceed 40%. The theoretical model in this paper fills the gap in the distributed parameter theory for eccentric coaxial structures and contributes to the advancement of microwave transmission line theory. The proposed modeling approach also provides a practical foundation for the optimized design and application of wellbore coaxial systems in microwave‐assisted oil recovery.

ABSTRACT With the acceleration of urbanization, the treatment of municipal solid waste (MSW) has become one of the global challenges. The waste incineration process will produce fly ash containing a large amount of heavy metals and organic matter. The aim of this work is to investigate the physicochemical properties of fly ash and its roasting mechanism to provide a scientific basis for the safe handling and resource utilization of fly ash. Through the systematic analysis of fly ash samples from several waste incineration power plants of Guangzhou Environmental Investment Co., it was found that the physicochemical properties of fly ash are affected by various factors, including fuel type, combustion mode, furnace structure, fly ash temperature, hygroscopicity, etc. Through laser particle size analysis, XRD, XRF, and other technical means, this study characterizes the physicochemical properties of fly ash in detail and investigates how these properties affect the deposition behavior and slaking characteristics of fly ash in the flue. The research results provide a scientific basis and technical support for preventing and solving the problem of ash plugging in the flue gas of boilers, thus promoting the continuous progress and development of waste incineration power plants generation technology.

ABSTRACT With the increasing global energy demand and the growing prominence of environmental issues, biodiesel has garnered significant attention as a renewable, low‐emission green energy source. Conventional hydrotalcite‐based catalysts often suffer from insufficient basicity and limited accessibility of active sites, leading to relatively long reaction times and limited efficiency. This study synthesizes Mg‐Al hydrotalcites composed of various metal salts via the co‐precipitation method and employs them as supports for K 2 CO 3 to efficiently produce biodiesel. The transesterification performance of different Mg‐Al hydrotalcite catalysts was evaluated using a three‐component reaction (rapeseed oil, methanol, and methyl acetate) under conditions of an oil‐ester‐alcohol ratio of 1:1:10, a catalyst loading of 10 wt%, and a reaction temperature of 60°C. Results indicated that Mg‐Al hydrotalcite derived from acetate metal salts using K 2 CO 3 as the precipitant achieved a high biodiesel yield of 98.79% within 15 min, which is substantially faster than most reported hydrotalcite‐based reactions that typically require 30–120 min under comparable conditions. TG‐DTA analysis revealed that the formation of potassium aluminum oxide after high‐temperature calcination, which provides more alkaline sites as suggested by CO 2 ‐TPD profiles, is a key reason for the high catalytic activity. BET and SEM analyses showed that the catalysts possess a large specific surface area and rich pore structure, significantly enhancing the dispersion of alkaline sites. These synergistic features enable ultrafast biodiesel synthesis and provide a promising strategy for designing efficient and sustainable solid base catalysts for large‐scale biofuel production.

ABSTRACT Understanding the effects of fixed and moving bars allows for the design of more efficient thermal systems by using dynamic obstacles to optimize natural convection. This study complements several numerical studies on the effect of bars in a closed cavity. We examine the phenomenon of heat transfer by natural convection within a square cavity heated on the left side and cooled on the right side, with an adiabatic bar undergoing periodic vertical motion with an amplitude U bar and period T bar . We use the finite element method to solve the guiding dimensionless nonlinear equations. Our focus is on the effect of the bar movement direction, displacement amplitude U bar (0.1–0.4), displacement period T bar (1/3–1), bar width B (0.05–0.2), Rayleigh number Ra (10 4 –10 7 ), and number of bars N (1–3) on the average Nusselt number, streamlines, and isotherms distribution. The results show that increasing Ra significantly improves heat transfer. Maximum heat transfer occurs at U bar = 0.1 and T bar = 1. Increasing bar width and number negatively affects the average Nusselt number. This work contributes to understanding how dynamic obstacles can optimize natural convection, offering insights for the design of more efficient thermal systems.

ABSTRACTThe valorization of agricultural pod wastes into biochar offers a sustainable pathway for waste management and the development of functional carbonaceous materials. This study comparatively evaluates biochars produced from cocoa, flamboyant, and locust bean pods using an autothermal top‐lit updraft gasifier with retort heating, a system designed to enhance efficiency in low‐resource settings. The novelty of this work lies in providing the first comparative baseline data on unmodified pod‐derived biochars synthesized under the same controlled gasification conditions. The results show that cocoa pod biochar exhibited the highest yield and superior textural properties, with a surface area exceeding 750 m2/g, while flamboyant and locust bean pod biochars displayed lower but comparable performance. Thermal analysis confirmed stability up to 250°C, while spectroscopic and microscopic characterizations revealed carbon‐rich structures with oxygenated functional groups, porous morphology, and embedded mineral elements. These features suggest broad applicability in adsorption, soil amendment, and catalysis, although application trials remain a direction for future studies. In conclusion, this research establishes a reference for pod‐based biochars and demonstrates the feasibility of simple, eco‐friendly gasification systems for biomass valorization, contributing to the circular economy and sustainable materials development.

ABSTRACTAromatics and hydrogenated aromatics constitute the primary constituents of the recycled solvent utilized in coal liquefaction. However, the presence of hydrogenated aromatics complicates the assessment of the effects of aromatic compounds during the coal liquefaction process. To eliminate the effect of hydrogenated aromatics, solvent‐free experiments and experiments with specific polycyclic aromatic compounds (pyrene, fluoranthene, phenanthrene, and naphthalene) were conducted, along with utilizing density functional theory calculations. Results show that the shuttle role of naphthalene is influenced by catalyst activity. In the presence of a low‐active catalyst, naphthalene acts as a shuttle agent facilitating indirect hydrogen transfer. However, with a high‐active catalyst, direct transfer of hydrogen from H2 to pyrolysis radicals occurs without involving naphthalene as an intermediary. Polycyclic aromatic compounds exhibit higher hydrogen shuttle ability (pyrene > fluoranthene > phenanthrene > naphthalene). The high hydrogen shuttle ability can be attributed to the higher reactivity in hydrogenation and lower energy barriers for hydrogen transfer. A nonradical hydrogen transfer pathway has been proposed, promoting cleavage of strong covalent bonds and enhancing the yield of asphaltene and preasphaltene. Additionally, π–π inter actions between polycyclic aromatic compounds and pyrolysis radicals have been evaluated. The interactions contribute positively to radical stability. Substances characterized by a greater number of aromatic rings display a more pronounced stabilizing effect on free radicals.

ABSTRACTChemical facilities storing large volumes of flammable liquids close to residential areas pose severe fire‐and‐explosion hazards that can escalate into disasters. In this study, a tank farm located within Istanbul's city limits is examined to evaluate possible catastrophic scenarios using consequence analysis methods. For this purpose, several release and ignition scenarios under varying wind conditions are simulated in ALOHA software. The results reveal a high likelihood of a pool fire propagating to nearby rural structures especially under a domino‐effect scenario placing all adjacent buildings within the lethal zone and some at risk of ignition. These findings demonstrate that proactive, region‐wide risk assessments including detailed land‐use planning are essential for accurately characterizing and mitigating hazards to both people and the environment.

ABSTRACTIndustrial wastewater treatment is a growing concern due to the discharge of pollutants/contaminants originating from different industrial sectors such as textiles, fertilisers, pharmaceuticals and dyes. These substances may adversely affect both ecological systems and living organisms. To minimise these effects, many treatment methods have been proposed, and out of all, photocatalysis is the most promising technology. This review offers a comprehensive examination of various photocatalytic materials and the underlying mechanisms governing the photocatalysis process. Factors that influence the photocatalysis process were also discussed. The study further reviews the advancements in the synthesis of photocatalytic materials using doping and heterojunction strategies. Finally, the study presents a comprehensive review of different photocatalysts used for various wastewater treatment applications.