This study systematically investigates the NH3 selective catalytic reduction (NH3-SCR) mechanism over Mnbased Zr-pillared montmorillonite (Mn/Zr-PILM) by combining experimental characterization with density functional theory (DFT) calculations. Catalytic performance evaluation shows that Mn/Zr-PILM exhibits excellent low-temperature denitrification activity, achieving a NOx conversion of 91.8 % at 473 K, which is 59.4 % higher than that of Mn-loaded sodium montmorillonite (Mn/NaMt). To elucidate the structural origins of this enhancement, detailed characterization was conducted, revealing that Zr pillaring increases surface roughness, generates a mesoporous architecture, and enriches surface acid sites, thereby facilitating reactant adsorption and activation. Subsequently, DFT calculations were employed to investigate the adsorption behaviors and reaction pathways of key species (NH3, NO, and O2) on MnO2, Mn-PILM, and MnZr-PILM surfaces. The results indicate that NH3 readily dissociates into NH2* intermediates under both aerobic and anaerobic conditions. Further energy barrier analysis demonstrates that the rate-determining steps vary significantly among the three surfaces, reflecting their distinct catalytic functions. Based on these findings, a structure-induced multi-site synergistic mechanism is proposed, in which NH3 activation, NO coupling, and final product formation proceed cooperatively on differentiated Mn sites, which provides mechanistic insight into low-temperature NH3-SCR and offers guidance for designing high-performance layered clay catalysts via pillar engineering.

Blast furnace gas (BFG) is a major source of carbon emissions in the steel industry. To address this, a novel dual chemical-looping process is proposed for producing H2/CO syngas from BFG while achieving decarbonization. The process integrates an oxygen carrier cycle and a carbon carrier cycle, coupling chemical-looping technology with integrated CO2 capture and utilization (ICCU), and utilizes coke oven gas (COG) as the reducing agent to convert all carbon in BFG into CO. Oxygen carriers and carbon carriers are screened from various candidate metal oxides. Among them, NiO, Fe2O3 and CuO as oxygen carriers exhibit high melting points, high oxygen transport capacities, high equilibrium constants, and strong spontaneity in reactions with CO, while CaO as the carbon carrier shows high CO2 desorption and adsorption capacity under required reaction conditions. With these selected carriers, the carbon fixation and release processes are systematically investigated through thermodynamic analysis, focusing on the effects of temperature, pressure, and feed ratio. Under the combined action of each oxygen carrier and CaO, both carbon fixation rates and CO yields nearly reach 100%, indicating that the proposed process achieves highly efficient decarbonization of BFG. Building on these findings, energy, environmental, and economic analyses are conducted. Compared to conventional processes such as pressure swing adsorption separation and dry reforming of methane, the proposed process exhibits lower energy consumption. Furthermore, it is environmentally advantageous, achieving net-negative carbon emissions in most scenarios across the three oxygen carriers, and economically viable, with a positive net present value (NPV).

Efficient thermal management of superheated surfaces via fine water mist impingement is critical across numerous industrial applications, yet quantifying and optimizing the intricate heat-mass coupling remains a significant challenge. Here, we reveal and quantify a nonlinear cooling enhancement/suppression mechanism driven by the transient coupling of droplet kinetic energy, Leidenfrost vapor film evolution, and interfacial heat transfer. Through the numerical simulations incorporating an interface-confined phase change model, we rigorously elucidate the genesis of the M-shaped heat flux distribution. We mechanistically attribute this M-shape to non-uniform central vapor accumulation and pressure-gradient-driven radial transport, demonstrating its non-uniform suppression on local heat transfer. Crucially, we identify and quantitatively define "critical impact conditions"-encompassing critical droplet size and critical impact velocity-that effectively circumvent the profound inhibition of the Leidenfrost effect to maximize cooling efficiency. For instance, increasing impact velocity from 0.50 to 1.00 m/s leads to a remarkable 110.2% surge in total heat transfer, marking a fundamental transition from a low-efficiency (14.9% increase for 0.25-0.50 m/s) to high-efficiency cooling regime. The identification of this abrupt, stepwise enhancement, rather than a gradual trend, confirms the existence of a critical velocity threshold-the finding that fundamentally extends beyond parametric sensitivity analyses prevalent in the literature. This study provides unprecedented mechanistic insights into droplet-wall heat transfer and offers a novel parameter-based cooling strategy for precise enhancement and optimization of high-temperature cooling processes.

To achieve effective improvement of dispersive soil's poor engineering properties, this study proposes a stabilization technique using steel slag as a calcium source synergized with CO2 mineralization for carbon sequestration. By inducing calcium carbonate cementation, the method achieves synergistic stabilization of dispersive soil and carbon sequestration. Samples with varying steel slag contents (0-20% at 4% intervals) and their carbonated counterparts were prepared, cured for 1-28 days, and tested for carbon sequestration capacity, mechanical properties, dispersibility, freeze-thaw durability (1-30 cycles), and microstructural characteristics. The experimental results demonstrate that minimal influence of curing age on soil properties. Carbonated samples with 20% steel slag achieved a 1239.4% increase in strength compared to untreated soil, reached a nondispersive state, and exhibited a carbon sequestration capacity of 124.03 g CO2/kg soil. The stabilized soil maintained stable mechanical and anti-dispersion performance under freeze-thaw cycling. Microstructural analysis revealed that pore filling and particle cementation by calcium carbonate constitute the primary soil improvement mechanism. The work provides an effective solution for dispersive soil disaster mitigation and industrial solid waste valorization, with broader applicability for eco-engineering strategies targeting soil-related hazards.

The development of advanced hierarchical activated carbons (ACs) is essential for overcoming mass-transfer limitations in catalytic processes and achieving high catalytic efficiency. Converting waste resins into hierarchical ACs for NO catalytic oxidation (NOCO) represents a scalable and cost-effective strategy. In this study, hierarchical waste ion-exchange resin-based ACs (WIRACs) were synthesized via trace K2CO3-induced catalytic physical activation. The effects of impregnation ratio, activation temperature, activation time, and activation flow rate on the textural properties and NOCO performance of WIRACs were systematically investigated. Results showed that the optimal preparation conditions for the WIRACs were at an impregnation ratio of 3%, activation temperature of 850 degrees C, activation time of 120 min, and activation flow rate of 140 ml/min, resulting in the highest NO conversion of 42% at 50 degrees C. Crucially, principal component analysis (PCA) was employed to quantitatively decouple the complex relationships between the cumulative pore volumes (V-c) within different pore-size ranges of the activated carbon and its NOCO performance. The PCA results revealed a synergistic effect of the hierarchical pore structure, demonstrating that the V-c in the 0.346-0.7 nm and > 2.116 nm ranges both played important roles in NOCO performance. V-c in the 0.346-0.7 nm control path and carbon active site control path were further proposed to explain the mechanism underlying NOCO. Finally, cyclic tests confirmed the excellent reusability of WIRACs, and a radar chart-based multidimensional evaluation demonstrated this strategy as a highly cost-effective and industrially viable route for the preparation and application of advanced hierarchical ACs.

The adoption of environmental protection and energy conservation measures has led to increased interest among researchers and scholars in the centrifugal granulation of metallurgical slag and waste heat recovery technology. Variations in the production processes of metallurgical slag result in significant disparities in the physical properties of slag from different sources. Blast furnace slag and copper slag are two types of metallurgical slags distinguished by their characteristic properties. Blast furnace slag exhibits higher viscosity and surface tension, whereas copper slag displays lower viscosity and surface tension, resulting in differing granulation characteristics. This study employs numerical simulations to examine the flow patterns during centrifugal granulation and elucidate the mechanism of centrifugal granulation. The study determined that the breaking length to tip diameter ratio was consistent with the findings of Weber's research. Additionally, it observed the atypical granulation evolution of two types of slag at elevated flow rates, and examined the variation rules of breakup wavelength, tip diameter, crushing length, particle size distribution, and average particle size across varying flow rates. The study also noted that the centrifugal granulation effect of copper slag was significantly influenced by its surface tension. The aforementioned findings can offer theoretical guidance for the implementation of the centrifugal granulation process in the treatment of metallurgical slag. (c) 2025 Published by Elsevier B.V. on behalf of The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Conventional ammonia production via the Haber-Bosch process is energy-intensive and carbon-heavy. Emerging biomass-based approaches offer a sustainable alternative but often lack rigorous system-level analysis based on actual reaction kinetics. This study presents a novel integrated process coupling biomass pyrolysis/gasification with Chemical Looping Ammonia Generation (CLAG) and waste heat recovery. Unlike previous models relying on simplified assumptions, this simulation incorporates experimental kinetic data for both N-absorption and N-desorption stages to ensure high fidelity. The system's energy and mass flows were rigorously evaluated using Aspen Plus. Results indicate that the gasification stage is optimal at an O2/biomass molar ratio of 0.2 and 750 degrees C. In the CLAG unit, a higher N-absorption temperature (1600 degrees C) and alpha-Al2O3/C ratio (3:3) significantly enhance ammonia yield. Under these optimal conditions, the system achieves a remarkably low energy consumption of 10.12 GJ/t-NH3 and specific CO2 emissions of 3.2 t/t-NH3-a reduction of over 60% compared to traditional coal-based routes. The integration of waste heat recovery is identified as a critical factor in minimizing net energy input. This work validates the feasibility of the biomass-based CLAG process as a low-carbon, energy-efficient pathway for sustainable ammonia synthesis.

Flue gas desulfurization characteristics of Mn-Ce metal oxides supported by ceramic-based diatomite and SBA-15 were systematically examined. The diatomite-supported sorbent (M2C2D6) achieved 96 % desulfurization efficiency, which can be attributed to its robust mechanical integrity and high porosity. In contrast to the diatomitesupported sorbent, the SBA-15-supported counterpart (M2C2S6) exhibited more uniform active component dispersion, leading to a marked elevation in breakthrough sulfur capacity (TSC) from 162 mg-SO2/g-sorbent to 469 mg-SO2/g-sorbent. Conversely, due to its lower porosity and diminished metal oxide affinity, heterogeneous surface distribution was observed on M2C2S6, impeding molecular interaction between SO2 and active sites. Consequently, a reduction in desulfurization efficiency to 65 % was recorded for M2C2S6. Desulfurization mechanisms were elucidated through integrated analysis of chemical reactions, external mass transfer, and internal diffusion processes. A novel Mn-Ce/diatomite-SBA carrier-blended sorbent was developed by synergistically combining the advantages of both carriers. When the diatomite: SBA-15 wt ratio reached 3:2, the hybrid sorbent (M2C2D6S4) demonstrated 96 % SO2 removal efficiency and 193 mg-SO2/g-sorbent TSC. Notably, across five consecutive desulfurization-regeneration cycles, M2C2D6S4 consistently outperformed the single-carrier M2C2D6 in TSC, underscoring its superior durability.

For melt granulation, sheet breakup formed by melt jet impingement is an efficient treatment method. This paper theoretically and experimentally investigates the flow and breakup characteristics of a curved liquid sheet formed by jet impinging on a circular plane. The results show that the overall degree of sheet bending decreases with the increase in sheet velocity, which can be used to determine the streamline of liquid sheets by the configuration method. Based on the obtained knowledge of the sheet dynamic, the disturbance dispersion equation of a liquid sheet with variable velocity is derived first. In the instability analysis of the liquid sheet element, the acceleration force working due to the sheet bending stabilizes the sheet disturbance. However, combining the overall motion and instability of the liquid sheet shows that, with the sheet’s bending and spreading, the increasing sheet velocity and the decreasing sheet thickness still promote the development of sheet disturbance. For the dominant breakup mode, the bending of the liquid sheet contributes to the delay of sheet breakup for bell-like sheets at low velocity. In contrast, the bending of the liquid sheet contributes to the advance of sheet breakup for umbrella-like sheets at large velocity. For the critical jet Weber number, the experimental value of the curved sheet is less than that of the planar liquid sheet, due to the increase in sheet velocity. The prediction methods of breakup length and droplet radius are proposed.

Molten magnesium chloride (MgCl2), a high-temperature by-product from titanium metal production, currently results in substantial thermal energy loss and environmental issues during conventional cooling. This research investigates rotary cup granulation technology to recover this significant waste heat and enhance the overall process safety and environmental performance. The study experimentally examined the breakup dynamics of molten MgCl2 at the rotary cup's edge, evaluating the influence of rotation speed, cup diameter, and mass flow rate on granulation characteristics. Principal findings indicate that rotary cup granulation effectively forms small, uniform spherical particles, predominantly ranging from 0.6 to 1.5 mm. At a rotating speed of 800 rpm, particle uniformity was optimal, with a standard deviation (S-value) below 0.245, suggesting favourable sphericity. Increasing mass flow rate, however, led to larger, less uniform particles and undesirable flake formation. This granulation process is foundational for enhancing waste heat recovery, as the resulting small and uniform spherical particles (0.6-1.5 mm) provide a large surface-area-to-volume ratio, making them an ideal medium for efficient heat transfer in subsequent recovery systems.

This study examines how varying reaction temperatures influence the N-desorption process, along with the development of a kinetic model for the reaction. The results indicate that higher temperatures enhance the N-desorption reaction, and that the shrinking core model provides the best fit for describing the reaction kinetics. The activation energy associated with the N-desorption process is 330.52 kJ/mol.

Particle adsorbents have gained significant traction in flue gas desulfurization applications, primarily attributed to their high structural homogeneity and large specific surface area. To address the multifaceted requirements of industrial sectors regarding the structural configurations and physicochemical properties of particle adsorbents while promoting sustainable manufacturing practices, this study systematically evaluates and critically appraises contemporary advancements in particle desulfurizing agent technologies. The synthesis of these findings establishes a theoretical framework to facilitate technological innovation and industrial progress within the particle desulfurizer domain. The research systems of particle adsorbents, encompassing active components, inert carriers, preparation methodologies, and gas–solid reaction models, were comprehensively reviewed. The advantages and current limitations of these systems were then systematically summarized. Finally, the fundamental principles and research trajectories in the application fields of distinct particle adsorbent research systems were elucidated. An analysis of the developmental trends indicated that enhancing the utilization efficiency of active components and improving the cyclic stability of adsorbents remained critical engineering challenges. It is posited that the pursuit of high reaction activity, thermal stability, mechanical strength, and superior anti-aggregation/sintering performance constitutes key directions for the advancement of particle adsorbents in China’s flue gas desulfurization industry.

Abstract Thermodynamic analysis was employed to evaluate an MBHE (moving bed heat exchanger) for heat recovery from BFS (blast furnace slag). The study conducted experimental investigations to assess the influence of several factors on heat transfer, exergy transfer, and exergy destruction, including the granular side Peclet number, waterside Reynolds number, arrangement, tube spacing, and tube shape. Structural parameters of the MBHE were optimized based on the heat transfer enhancement number, resulting in the determination of the optimal parameters: staggered arrangement, Dh/D=2, Dv/D=3, and elliptical tubes.

Biochar from slow pyrolysis was applied to Chemical Looping Ammonia Generation (CLAG) to avoid the preparation of ammonia from fossil fuels and relatively expensive H-2. The effects of pyrolysis atmosphere, temperature, heating rate, and residence time on the biochar reactivity in the N-adsorption reaction were investigated. The relationship between specific surface area, average pore diameter, micropore percentage, and disorder degree of biochar on reactivity was evaluated by simple and multiple linear regression and Analysis of Variance (ANOVA). The results showed that the biochar prepared in a CO2 atmosphere with a pyrolysis temperature of 700 degrees C, a heating rate of 10 degrees C/min, and a resident time of 30 min had the highest conversion rate of 57.79 % in the N-absorption reaction. When the pyrolysis temperature was increased from 600 degrees C to 700 degrees C, the biochar conversion in the N-adsorption reaction was significantly increased due to the Boudouard reaction during biomass pyrolysis. The linear regression and ANOVA results show that the micropore percentage and disorder degree of biochar significantly positively affected the reactivity, guiding feedstock selection and optimization of the preparation method of the carbon source used for CLAG.

The study conducted isothermal tests for biochar-based N-absorption reaction in Chemical Looping Ammonia Generation to investigate the factors affecting biochar conversion, the kinetic model, and the reaction mechanism. The results show that the N2 gas flows had little effect on biochar conversion. Raising the reaction temperature and the molar ratio of α-Al2O3 to C enhanced the conversion of biochar. When the N2 flow rate was set to 200 mL/min, the reaction temperature to 1600 °C, and the α-Al2O3/C molar ratio to 3:3, the biochar conversion reached its peak at 95.45%. After evaluating several kinetic models, the D1 diffusion model was found to provide the closest match to the biochar conversion. The activation energy decreased from 241.91 kJ/mol at a 1:3 α-Al2O3/C molar ratio to 146.77 kJ/mol at a 3:3 ratio with an increasing α-Al2O3/C molar ratio. The biochar’s high specific surface area and abundant pore structure facilitated a rapid reaction between carbon and oxygen on the carbon surface. Additionally, the diffusion of oxygen produced during the decomposition of α-Al2O3 became the limiting factor in the N-absorption reaction.

Introducing cooling airflow is an effective method for achieving the localized cooling rate required during waste heat recovery of blast furnace slag. However, the associated parasitic loads must be considered. This study investigates moving bed heat exchanger with airflow-assisted cooling from an exergy perspective. The effects of the granular side Peclet number, airflow side Reynolds number, and the height ratio of the airflow section on heat loss, exergy destruction, and its distributions were examined experimentally. The results show that the trends of temperature and pressure exergy destruction with each parameter tend to be opposite. Therefore, optimizing the parameters requires a trade-off between different types of destruction. Additionally, reducing exergy destruction while meeting the cooling rate requirement was considered. The optimal parameter set was determined by taking the cooling rate requirement as a constraint and minimizing the dimensionless temperature and pressure exergy destruction to obtain the Pareto front.

Chemical looping ammonia generation is a promising, efficient, and environmentally friendly synthesis of ammonia by cycling N-absorption and N-desorption reactions. A portion of the generated NH 3 decomposes at the reaction temperature of the N-desorption reaction. In order to promote the N-desorption reaction and inhibit the decomposition of NH 3 , the effect of alpha-Al 2 O 3 loading on the N-desorption reaction was investigated in this paper by fixed-bed experiments. The mechanism was revealed using Density functional theory (DFT) calculations. The results showed that when the reaction temperature increased, the conversion of AlN and the yield of NH 3 increased, but the actual NH 3 conversion decreased. When the steam concentration increased, the conversion of AlN, the yield of NH 3, and the actual NH 3 conversion increased. The loading of alpha-Al 2 O 3 could facilitate the Ndesorption reaction and inhibit the decomposition of NH 3 . The 40 wt% alpha-Al 2 O 3 had the highest conversion of AlN. The 80 wt% alpha-Al 2 O 3 had the highest yield of NH 3 . The actual efficiency of ammonia production at 1075 degrees C with 80 wt% load increased from 45.5% without load to 58.5%. The DFT calculations revealed the mechanism: alpha-Al 2 O 3 surface promotes the dissociation of H 2 O molecules to make more hydroxyl groups in the reaction system, which promotes the transfer of H + and the N-desorption reaction. Meanwhile, the adsorption of NH 3 by the alpha-Al 2 O 3 surface protected NH 3 and inhibited its decomposition.

Climate change posed the greatest threat to human sustainable development, and reducing carbon emissions was a pressing issue for all humanity. Among the most energy-intensive and carbon emissions industries, the iron and steel industry (ISI) represented almost 5% of energy consumption and 7% carbon emissions around the world. The ISI faced severe challenges from the “relative constraints” of carbon emissions intensity to the “absolute constrains” of total carbon emissions. Waste heat played an indispensable role in the low-carbon development of ISI. The heat contained in the blast furnace slag (BFS) was considerable, and it was an important position to be occupied. In recent decades, the proposal and development of dry centrifugal granulation (DCG) technology had provided researchers with great encouragement and brought the dawn to overcome the problem of slag waste heat recovery. This technology had been hailed as one of the most suitable technologies to boost sustainable transition of the ISI. This paper provided a detailed review of DCG technology including granulation characteristics of BFS, flight and impingement behavior of slag particles, slag transformation in granulation chamber, waste heat recovery process, etc. Furthermore, the implementation and technical characteristics of semi- and industrialization implementation for DCG technology were explored and elaborated as comprehensively as possible. Ultimately, the problems existing in the development of this technology were analyzed, and suggested the future direction and challenges. This paper aiming to pave the way for the waste heat recovery of BFS while supporting the market penetration and enhancing the role in the fight against climate change for ISI.

The free liquid sheet formed by jet impingement often has a certain bending, and this paper focuses on the influence of this bending on the rim dynamics and instability. The derivations of the rim retraction and the flow trajectory of the curved liquid sheet show that the length of the flow trajectory reaching the equator is the same as the Taylor–Culick radius representing the rim retraction equilibrium. It is inferred that the stable radius corresponding to the curved trajectory must be less than the Taylor–Culick radius, that is, a curved liquid sheet cannot reach the stable position by the rim retraction equilibrium alone. Experimental results confirm that the greater the degree of liquid sheet bending, the farther the stable radius from the Taylor–Culick radius. In addition to the rim retraction, the rim can remain in a stable position with the help of the fingerlike cusp, formed due to instability, deflecting liquid momentum. The dispersion equation of rim instability is derived to obtain the maximum growth rate of disturbance and corresponding wavelength. The surface tension is the main driving force of rim instability, and the liquid flow from the liquid sheet into the rim inhibits the rim instability. With increasing We, the decreasing local liquid sheet thickness increases the growth rate of disturbance and decreases the instability wavelength, which causes the rim to destabilize at a smaller rim radius, resulting in the corresponding decrease in droplet radius. The experimental results agree well with the theoretical prediction.