Asia-Pacific Journal of Chemical Engineering最新文献

This paper provides a critical evaluation of Madhavarao Kulkarni's research “Mixed Convective Magnetised GO-MoS₂/H₂O Hybrid Nanofluid Flow About a Permeable Rotating Disc” published in Asia-Pacific Journal of Chemical Engineering, as well as relevant comments. The author aimed to provide self-similar solutions to the flow problem discussed in the paper. The critics of Kulkarni contend that the proposed governing equations and similarity transformations are erroneous, undermining the subsequent mathematical study, leading to erroneous physical interpretation of the resultsthat contradict the physical laws governing the flow. The conclusions drawn by Kulkarni is incorrect.

The current study aims to analyze the sludge characteristics of typical anaerobic–aerobic (AO) process sewage treatment plants (WWTPs) in the Taihu Lake basin, China. The study found that the majority of WWTPs employed plate and frame filter press dewatering with polyacrylamide as a flocculant material. T-tests for organic matter and calorific value revealed a significant difference (p ≤ 0.05) between urban and industrial WWTPs, with urban WWTPs being higher overall. The correlation analysis revealed that Cr, Cu, Pb, and As were significantly positively correlated (p ≤ 0.001), whereas the principal component analysis revealed that the heavy metals in principal component 1 consist of As, Pb, Cu, Hg, and Cr (49.2% contribution), probably due to their common origin from electroplating, dyeing, and printing. The potential ecological risk assessment revealed that the levels of Cd, Hg, and Cu in sludge and sewage need to be strictly regulated.

Against the backdrop of the “carbon peaking and carbon neutrality” goals, hydrogen-blended natural gas (HBNG) has emerged as a pivotal pathway for the low-carbon transition of the gas industry. However, the combustion characteristics of HBNG in in-service gas-fired heating and hot-water boilers remain underexplored, particularly regarding systematic experimental data on combustion stability, pollutant emissions, and thermal performance under high hydrogen blending ratios. To investigate the combustion characteristics of gas-fired heating and hot-water boilers using HBNG, the paper established an experimental system; typical in-service conventional atmospheric gas-fired boilers, as well as fully premixed condensing gas-fired boilers, were selected as test samples; pure methane (0% H₂ + 100% CH₄) and blends of 20% H₂ + 80% CH₄, 40% H₂ + 60% CH₄, 60% H₂ + 40% CH₄ were used as test gas. Experiments were conducted on heat input, thermal efficiency, exhaust gas temperature, combustion products (O₂, CO₂, CO, NO_x), combustion flame, ignition flame, ignition, and operational noise. The results indicate that the thermal performance under hydrogen blending can still meet the requirements stipulated in the corresponding national standard GB 25034. However, several issues were identified: as the hydrogen blending ratio increased, noticeable flame light-back was observed in the atmospheric boilers; the length of the combustion flame gradually shortened, with a maximum reduction of nearly 70%. One boiler experienced momentary deflagration when the gas source was 60% hydrogen, and abnormal noise was observed during the operation of some prototypes. It was confirmed that the use of hydrogen-blended gas in in-service heating boilers alters the original combustion process. This study reveals the influence of hydrogen blending ratios on the combustion and heat transfer of in-service gas-fired boilers, providing a reference for proposing optimization methods for the combustion and heat transfer of in-service boilers using hydrogen-blended gas.

In the present study, both model test and numerical simulation were carried out on comprehensive investigations on pollutant diffusion performance with dual release sources in a rubber processing plant. The hybrid natural air intake combined mechanical exhaust mode was designed for the industrial plant for removal of hazardous pollutants. The scaled model test was conducted to supply model validation data on pollutant dispersion. The realized k-ε model was used to predict pollutant dispersion in the actual industrial plant. Compared with obtained test results, the computational deviations of the numerical model could be limited within ±10%. The effects of air change rate, window height, and exhaust vent arrangement on the removal of hydrogen sulfide (H₂S) were investigated. As air change per hour (ACH) increases from 20 to 25 h⁻¹, the average concentration of H₂S in the industrial plant decreased by 12.7%. With ACH of 20 h⁻¹, the average concentration of H₂S in industrial plants increases from 9.467 to 10.383 mg/m³ when window height increases from 0.5 to 2.5 m. With ACH of 20 h⁻¹ and window height of 0.5 m, the ventilation method arranged with exhaust outlets reduces the average concentration of H₂S > 35.0%.

Oil spills pose severe environmental and economic consequences, necessitating effective mitigation strategies. Despite the widespread use of chemical dispersants, gaps remain in understanding the relationship between turbulent energy, dispersant effectiveness, and real-world spill conditions. This review addresses this gap by analyzing how turbulence, wave action, and energy dissipation rates influence oil dispersion. Utilizing Kolmogorov's −5/3 law, experimental wave tank studies, and laboratory flask tests, we quantify energy dissipation and its effect on droplet formation and dispersion. Results indicate that energy dissipation rates exceeding 10⁻⁴ W/kg significantly enhance dispersant efficiency, with Corexit 9500 achieving up to 75% dispersion under high-energy conditions. The findings provide critical insights into optimizing dispersant application based on real-time hydrodynamic conditions, thereby improving response strategies for oil spill mitigation.

In this study, SBA-15 was loaded with 1 wt% Pt-Ni bimetallic catalysts to improve the hydroisomerization and hydrocracking of n-heptane (C7H16). The structural and textural features of the catalysts, both with and without encapsulated SBA-15, were examined using XRD, FTIR, SEM/EDS, BET, and TEM techniques. Catalyst activity was tested in a fixed-bed reactor with a controlled flow rate and pressure, within a temperature range of 250°C–400°C. The Pt-Ni (1%)/SBA-15 catalyst achieved a high n-heptane conversion of up to 97% at 400°C. However, the isomerization selectivity remained relatively low, with cracking reactions dominating at higher temperatures, which limits the catalyst's practical use. Although the Pt-Ni/SBA-15 catalyst shows promising high conversion rates of n-heptane, its limited isomerization selectivity and tendency for cracking at elevated temperatures restrict its real-world application. Future research should focus on adjusting the catalyst's acidity, optimizing metal loading, and modifying supports to enhance selectivity and lower operating temperatures.

Asphaltene deposition, especially near the wellbore, where pressure declines below the bubble point, remains a critical threat to flow assurance in oilfield operations. This study hypothesizes that a multifunctional, sustainable, and eco-friendly hybrid nanofluid based on ZnO and biodegradable surfactant can overcome these asphaltene-related issues while simultaneously improving crude oil characteristics. A modified asphaltene dispersion test, designed without toluene addition to prevent overestimation of inhibitor performance, was conducted on different crude oil systems to evaluate inhibitor efficacy under realistic conditions. The nanofluid with a concentration of 900 ppm has achieved 99.6% asphaltene dispersion stability over 1 week, taking advantage of various asphaltene–nanoparticle mechanisms such as adsorption, steric hindrance, and electrostatic repulsion. In the most problematic crude oil system, marked by high salt and water content, inhibition surpassed 70%. Fluorescence microscopy further validated these findings by demonstrating the disaggregation of asphaltene clusters. Additionally, the nanofluid demonstrated corrosion inhibition by 100% hydrogen sulfide (H₂S) scavenging, 55% sulfur reduction, and crude oil viscosity reduction ranging between 10% and 48%, depending on the crude oil system. This research presents an innovative multifunctional solution to flow assurance issues in a single low-cost formulation, eliminating the need for multiple chemical treatments, which aligns with the industry's shift toward sustainable and integrated oilfield management strategies. The results provide a base for future field-scale validation and long-term stability assessment of nanofluids under reservoir conditions.

Conventionally, bulk liquid membranes (BLM) utilize hazardous chemicals as the carrier and diluent to prepare the membrane phase. This study presents a greener alternative by formulating BLM with a deep eutectic solvent (DES) as the membrane phase, thereby eliminating the need for separate chemicals as carrier and diluent. Cetyltrimethylammonium bromide (CTAB) and oleic acid (OA) were used as the hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), respectively. This study identified the suitable HBA:HBD ratio for DES synthesis, characterized its physicochemical properties and extraction equilibria and evaluated the DES performance as the membrane phase in BLM. In this study, the HBA:HBD ratio was varied from 1:30 to 1:80. Fourier transform infrared spectroscopy and thermogravimetric analyses confirmed the formation of DES between CTAB and OA. Meanwhile, the extraction equilibria demonstrated the extraction capability of DES and confirmed the stoichiometry of Zn(II) ions extraction. The equilibrium constant was found to be 0.7167 and the stoichiometric ratio of 1:1 between DES and Zn ion. Finally, the maximum Zn(II) ions removal efficiency (89.30%) was achieved at an HBA:HBD ratio of 1:40 DES as the membrane phase. The results were obtained under conditions where the stirring speed, temperature and operation time were 300 rpm, 60°C and 240 min, respectively.

Increased worldwide demand for renewable energy has triggered considerable evolution of solar photovoltaic (PV) technology, which harnesses sunlight for electricity. Yet, one of the main problems in achieving PV maximum efficiency is heat, which the cells produce during operation, as high temperatures lower cell efficiency and overall performance. Therefore, heat generated is controlled using the proposed cooling method. The proposed research is based on edible oils such as olive oil, sunflower oil, and castor oil as coolant medium. These oils are used in first timeact as phase-changing material (PCM) in cooling the monocrystalline and polycrystalline panels through an incorporated oil box fixed on the rear side of the PV panel. Oil is allowed to flow from the storage tank to the rear side of the unit and into the collector tank. Thus, the heat of the front side PV panel is reduced. The research surface methodology (RSM) is used to optimize and enhance the efficiency. The significant inputs of the proposed analysis are Capacity (C), Time (T), Temperature (H), and the Output Power (P). The optimal condition for P is at [C] of 95%, [T] of 30 min, and [H] of 68.5°C. The critical results obtained for castor oil in monocrystalline and polycrystalline PV panels are reduction in temperature by 3.29°C and 4.35°C and increase in efficiency by 17.25% and 20.7%, respectively. Castor oil proved to be superior compared to other edible oil in terms of physical, chemical, and thermal properties and stability. Finally, the proposed methods are integrating the natural coolant selection, innovative backside cooling tank design, and easy oil management for enhanced thermal regulation and sustainable operation.

The pyrolysis kinetics of herb residues with potassium and iron addition were investigated using thermogravimetric analysis (TGA) and a four-logistic distribution activation energy model (4LG-DAEM). The model included hemicellulose, cellulose, lignin, and a pseudo-component for coke. Kinetic compensation effects and n-order mechanism functions were incorporated to better fit the catalytic pyrolysis process. Compared with conventional models, the 4LG-DAEM captured the TG curve characteristics more accurately, with R² values above 0.995. Fitted parameter analysis showed that potassium addition significantly reduced the activation energies of cellulose, hemicellulose, lignin, and biochar reactions, but narrowed the reaction temperature ranges. Iron addition had a smaller effect on activation energies but widened the reaction temperature range. The combination of potassium and iron had a synergistic effect, enhancing the secondary reactions of hemicellulose, cellulose, and coke more effectively than single catalysts. Potassium–iron composite catalysts notably increased the proportion of biochar secondary reactions in the total process. Additionally, the 4LG-DAEM model demonstrated strong predictive ability for the kinetics of potassium–iron catalyzed pyrolysis of various biomasses.