Iranian Journal of Chemical Engineering (IJChE)

Abstract This study presents a neuro-fuzzy inference system for predicting the pressure loss in coiled flow inverter (CFI) tubes. Computational fluid dynamics (CFD) simulations were conducted to obtain the amounts of the pressure loss across nine distinct configurations of CFI. The neuro-fuzzy model utilized three key input parameters of the Reynolds number (Re), number of 90° bends (N), and tube-to-coil diameter ratio (L/D). Following CFD validation, the dataset was partitioned into training (two-thirds) and testing (one-third) subsets. The model achieved an outstanding mean relative error (MRE) of 0.549%, demonstrating its high predictive accuracy and reliability for the estimation of the pressure loss in coiled flow inverter systems. These results highlight the neuro-fuzzy approach as a suitable tool for optimizing CFI designs in industrial applications. This study ultimately demonstrates how the strategic combination of numerical simulation and machine learning can accelerate development cycles while maintaining rigorous accuracy standards, providing engineers with a powerful tool for system design and optimization. 

Abstract The synthesis of methanol is a key industrial process, but its performance is constrained by equilibrium conversion, heat dissipation, and energy inefficiencies. This study simulated the multi-bed adiabatic reactor of the Methanol and Derivatives Complex (CP1Z) located in Arzew, Algeria by Aspen HYSYS. Two reactor models were evaluated: the Equilibrium Reactor (ER), based on Gibbs free energy minimization, and the Plug Flow Reactor (PFR), which incorporates detailed kinetics. Both models were validated against industrial plant data to assess predictive accuracy. The ER model demonstrated better agreement with industrial data, particularly for the concentration of methanol (0.36% deviation), and was therefore selected for process improvement studies. Two modifications were introduced. First, recycling unreacted syngas increased the production of methanol from 613 kmol/h to 1800 kmol/h, a 193% improvement. Second, replacing air coolers with a heat exchanger–steam turbine system enabled the recovery of 1100 kW of electricity without reducing the methanol yield. When both modifications were applied simultaneously, the methanol output rose to 1917 kmol/h (+213%), and electricity generation increased to 1763 kW. The integration of the recycling of syngas and waste heat recovery substantially enhances the conversion efficiency, energy utilization, and sustainability of the production of methanol. Since these modifications require no major hardware changes, they offer a practical and scalable strategy for improving the technical, economic, and environmental performance of existing industrial methanol plants. 

Abstract In contemporary society, a plethora of human industries are fundamentally dependent on the antibacterial capabilities of various nanoparticles, rendering their absence in contemporary applications nearly unimaginable. Silver nanoparticles (AgNPs) are widely used for their potent antibacterial properties in various applications, including medical and industrial settings. Controlling microbial growth is critical to prevent health and environmental issues. In this study, AgNPs is biosynthesized using the Celtis caucasica leaf extract, optimizing synthesis parameters to achieve high purity and uniform particle size. The ideal synthesis parameters involved combining 1.5 mL of plant leaf extract with 10 mL of a 3 mM AgNO3 solution, maintaining a pH of 7, and heating the mixture at 70 °C for 45 minutes.UV-Vis, FTIR, and TEM analyses verified the synthesis of nearly spherical AgNPs with a mean size of approximately 20 nm, displaying a typical SPR absorption peak at 425 nm. FTIR data revealed key bioactive groups in the extract that enabled Ag⁺ ion reduction. The AgNPs showed robust antibacterial effects against Staphylococcus aureus (MIC 12.5 µg/mL) and Escherichia coli (MIC 25 µg/mL).

Abstract Centrifugal pumps are extensively employed in mining, petrochemical, and wastewater treatment industries, where handling solid–liquid two-phase flows often results in the erosive wear of internal components. This study investigates slurry-induced erosion in a single-stage centrifugal pump through a three-dimensional CFD model developed in COMSOL Multiphysics. The model integrates Lagrangian particle tracking with an empirical erosion correlation and is validated with experimental data reported in the literature, showing good agreement with an average relative error of below 5%. Parametric simulations were conducted to examine the effects of two key operating parameters: flow rate and particle concentration. The results indicate that at sub-design flow rates, the prolonged particle residence time increases impact frequency, leading to severe localized erosion near the blade leading edges. Conversely, operating at rates close to the design flow rate and up to 1.4 Qd reduces erosion intensity and promotes a more uniform wear distribution. Increasing particle concentration produces a nearly linear rise in the maximum erosion rate—from approximately 3 mm/year at 0.5% to over 22 mm/year at 3%—while also expanding the affected blade area. Moreover, larger particles intensify erosion severity and shift erosion zones toward the downstream blade regions, altering the wear mechanism. Overall, the validated CFD framework provides a robust and predictive tool for evaluating both erosion intensity and spatial distribution in slurry-handling centrifugal pumps. The findings emphasize the importance of optimizing operational parameters and applying wear-resistant materials to enhance pump durability and reduce maintenance costs. 

Abstract The pyrolysis of polyethylene terephthalate (PET) was investigated across a broad range of final temperatures, from 478°C to 640°C, yielding various products. Infrared radiation was employed as the heat source in this study. To minimize experimental deviations, each test under fixed conditions was repeated twice, and the results were compared for consistency. The primary objective was to evaluate the quantitative and qualitative differences in the products generated through this novel heating method, aiming to enhance the understanding of the pyrolysis process and the influence of the heating rate on the final outputs. Pyrolysis was conducted in a vertical tubular reactor housed within an infrared furnace. The average heating rates varied significantly, ranging from approximately 20.61°C/min in the slowest test to 161.12°C/min in the fastest one. The solid residue (char) resulted from PET pyrolysis was analyzed. The yields of 87.5% and 91% were recorded for the slowest and fastest heating rates respectively. These char samples were assessed using Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) to compare their quantity and quality. The findings revealed that the heating rate during the infrared pyrolysis of PET has a direct correlation with the quantity of valuable products, but an inverse relationship with their quality. 

Abstract Nanostructured SAPO-34 zeolites were synthesized using TEA/morpholine as dual templates through a hydrothermal approach, with the crystallization time as a key parameter. Different characterization methods of XRD, FESEM, EDX-dot mapping, BET, and FTIR were used to analyze these materials. The results demonstrated that the crystallization time was an efficient factor for determining the crystalline phase and uniformity of the final products. Additionally, the size and uniformity of cubic SAPO-34 particles enhanced in longer crystallization times. It was found that the SAPO-34 catalyst synthesized in the crystallization time of 72 h had an optimal distribution of silicon within the crystal lattice structure, resulting in a significant enhancement of its catalytic performance. This catalyst demonstrated the moderately stable production of highly desired olefins, maintaining the selectivity of 58% for ethylene and 38% for propylene over 10 h on stream. The possible reaction mechanism for the MTO process utilizing the prepared SAPO-34 material is proposed.