Chemical Engineering & Technology最新文献

In this paper, the seeded batch cooling crystallization of sodium phosphite (SP) is simulated and optimized through a coupled method of the genetic algorithm and nonlinear programming. At first, the modeling and simulation test methods of the crystallization process are applied for the crystallization of SP, which expands the relevant study of SP from the experiment to the simulation. A comprehensive model is established in MATLAB/Simulink, and based on this model, the results of the common cooling strategy (linear cooling) on the process are investigated. Meanwhile, the process sensitivity to the change of seeding conditions is analyzed. Then, the coupled optimization method based on the genetic algorithm and nonlinear programming is applied to optimize the crystallization process for the first time, and the obtained optimized cooling strategy is compared to the result of the traditional nonlinear programming method (NLPM). The traditional NLPM has more significant effects on large seeding mass and small mean size, while the coupled method has better adaptability. When the coefficient of variation is almost fixed, the cooling strategy obtained by the coupled method could produce more crystals with large mean size. In addition, the end of the process can be reached earlier. The results show that the coupled method is more suitable for the optimization of the batch cooling crystallization of SP.

LiNi_1/3Mn_1/3Co_1/3O₂ (NMC 111) materials show promise as cathodes for lithium-ion batteries (LIBs). However, their widespread use is hampered by various technical challenges, including rapid capacity fading and voltage instability. The cathode materials synthesized using the combustion method were annealed at various temperatures ranging from 650 to 900 °C for 24 h. In this study, we identified an optimal annealing temperature of 750 °C for LiNi_0.3Mn_0.3Co_0.3Ti_0.1O₂ (NMCT) materials. NMCT-750 exhibits an initial discharge capacity of about 140.1 mAh g⁻¹ and retains the capacity of 91 % after 30th cycles. The good performance of NMCT-750 is directly attributed to reduced cation mixing and the establishment of a stable structure with small particle sizes. In contrast, higher annealing temperatures (850 °C) lead to a rapid increase in primary particle size and result in poor cycling stability. Therefore, NMCT-750, annealed at 750 °C, holds great potential as a cathode material for the next generation of LIBs.

In the present work, a ZnS:Ni loaded on sponge-activated carbon (SAC) was synthesized and applied as an effective adsorbent to remove bromophenol blue (BPB) dye from aqueous solutions. Various techniques such as Fourier-transform infrared, X-ray diffraction, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller (BET) were used to characterize ZnS:Ni–SAC. The effective parameters such as BPB concentration, amount of ZnS:Ni–SAC, ultrasonic time, and pH of the aqueous solution were investigated and optimized by response surface methodology. To investigate the accuracy and reliability of the proposed method, the analysis of variance was used based on p-values and F-test. The optimal values of the parameters were obtained using the desirability function, and they were as follows: 15 mg L⁻¹ BPB concentration, 20 min sonication time, 18 mg of ZnS:Ni–SAC, and pH = 7. To evaluate the adsorption mechanism and calculation of maximum adsorption capacity, different adsorption isotherms were studied, and according to the obtained results, the Langmuir isotherm model showed the highest compatibility due to its higher R² (0.997). Also, the proposed adsorbent represented good adsorption capacity (125 mg g⁻¹). Moreover, kinetic studies proved the applicability of the pseudo-second-order model (R² = 0.986) compared to other models. The achieved results confirmed the applicability of ZnS:Ni–SAC as a versatile adsorbent for the removal of BPB.

To investigate chlorine adsorption from water onto resins, some batch adsorption tests were considered. The mechanisms and characteristic parameters of the adsorption process were analyzed using isotherm models which revealed the following order (based on the coefficient of determination): Flory–Huggins (0.99) > Fowler-Guggenheim (0.98) >, and Langmuir (0.38).The experimental data were examined using two kinetic models, including first- and second-order ones with R² value of 0.88, 0.1 respectively. According to the adsorption isotherm study, the Flory–Huggins isotherm model better fit adsorption on the surface of resin, as compared to other models. Assessing the thermodynamic parameters found out that the adsorption of Cl onto resins became an exothermic and spontaneous process. The results were then obtained. Similarly, the results of the experiment were provided via the computational fluid dynamics evaluation. Moreover, the results obtained by computational fluid dynamics were compared with the experimental data, and their accuracy was proved. Subsequently, the effects of changing the design and operating parameters, including flow rate (3, 6, 10 L min⁻¹) and bed height (10, 20, 40 cm) on the performance of this tower were studied. The results showed that by reducing the adsorbent, the adsorbed Cl increased and a longer bed was required for adsorption, which was not cost-effective. The amount of adsorption decreased as the flow rate increased, indicating that there was little contact between the Cl and the adsorbent.

The primary focus of the twenty-first century has been on developing new and cleaner fuels from renewable sources. The increasing availability of renewable energy sources in environment, such as lignocellulosic biomass derived from agricultural and forest residues, has created a plethora of opportunities for biofuel production. For this purpose, the search for appropriate waste biomass source and the design of suitable reactors are very essential, where the latter requires the knowledge of kinetic triplets. These requirements paved the way to the novelty of the present work as a selection of a rarely used biomass source, that is, Peltophorum pterocarpum, and its non-isothermal thermogravimetric analysis for the evaluation of kinetic triplet of the process. The range of temperature is 298–1173 K attained at heating rates of 10–55 K min⁻¹. Kinetics were estimated using differential Friedman method (DFM), distributed activation energy method (DAEM), Ozawa–Flynn–Wall (OFW), Kissinger–Akahira–Sunose (KAS), and Starink (STK) models. Mean activation energy (kJ mol⁻¹) and pre-exponential factor (min⁻¹) of pyrolysis process by five models were 183.68 and 1.24 × 10¹⁷ for DAEM, 194.28 and 3.08 × 10²¹ for DFM, 183.68 and 4.40 × 10¹⁶ for KAS, 184.12 and 2.12 × 10¹⁴ for OFW, and 183.93 and 3.56 × 10¹⁶ for STK. Average values of changes in Gibbs free energy, enthalpy, and entropy by five models are 174 kJ mol⁻¹, 178 kJ mol⁻¹, and 0.007 kJ mol⁻¹ K⁻¹, respectively. Criado's master plots revealed distinct reaction pathways during the process for different conversion levels.

Conductive polymer composites (CPC) are gaining increasing popularity due to their unique characteristics, which include light weight and the ability to conduct electricity. In this work, CPC were prepared by blending the polylactic acid (PLA) with a conductive filler, graphene nanoplatelets (GNP), at dosages ranging from 1 to 12 wt % using an internal mixer. The hot press machine was used to compress the CPC into thin sheet, and subsequently characterized for tensile, thermal, and electrical properties. The results showed that the addition of GNP at 7 wt % (percolation threshold) successfully transformed the PLA into an electrically conductive material. The tensile modulus increased with added GNP, but elongation at break and tensile strength exhibited an opposite trend. The incorporation of GNP also enhanced the composite's thermal stability.

Plastic waste is utilized aggressively for food, product packaging, cosmetics, toys, clothes, and even furniture. As a result, discarded plastic as a waste has grown uncontrollably worldwide, most of it ending up as landfill. With increasing concern, researchers have made efforts to convert this plastic waste into a more useful product. Along these lines, this study focuses on producing 10 tons of diesel per day through fast pyrolysis at 450 °C in the fluidized bed reactor for a feed rate of 3000 kg of plastic waste per hour. The production was simulated in Aspen HYSYS V11 to ensure the desired yield. Further, a detailed economic analysis is carried out to estimate the return on investment and total cost per year, as well as the payback period and the profit for different scenarios.

Capturing carbon dioxide is vital for mitigating global warming and supporting chemical processes. Ionic liquids (ILs) have emerged as promising solvents for CO₂ capture. Using ASPEN simulation software, this study explores three specific ILs: [emim][triflate], [bmim][MeSO₃], and [bmim][NTf₂]. Their selection is based on exploitable differences in energy. The study models CO₂ solubility and validates it against published data. It also considers the decomposition of ILs using a more accurate vapor loss model. Simulated equations predict CO₂ and IL behavior more accurately than published ASPEN studies, optimizing the process for minimal energy consumption. Commercial considerations and rigorous engineering calculations guide the analysis, encompassing energy and economic factors.

The present work examines the computational analysis and mathematical modeling of peristaltic blood flow in a tapered channel, taking into account slip boundary conditions, Hall current, and Soret–Dufour forces. By neglecting the wave number and employing a long-wavelength approximation to analyze the fluid model, the investigation was conducted within the framework of a low Reynolds number regime. The study reveals that the values of the Soret number, Dufour number, Prandtl number, and Schmidt number exhibit an upward trend as the fluid temperature rises. In contrast, a rise in the thermal slip parameter causes the fluid temperature to fall. It has been shown that when the mass slip parameter increases, the fluid's concentration rises. The skin friction coefficient rises within the range of x = 0.55 to x = 1 as the velocity, concentration slip parameter, Soret number, and Dufour number increase. Conversely, the skin friction coefficient decreases as the thermal slip parameter increases. The selected characteristics exhibit realism since they find use in many fields such as medical biology, biomechanics, heat exchangers, gas turbines, and several other domains.

The mixing mechanism in an oscillatory baffled reactor (OBR) at the low oscillatory Reynolds number was analyzed using numerical simulation. OBR is a tubular reactor in which baffles are placed at equal intervals, and the interaction between the baffles and oscillatory flow mixes the fluid. At the low oscillatory Reynolds number, mixing induced by the folding and stretching of the fluid was observed at each baffle section. This was caused by the radial flow in the vicinity of the baffles when the direction of the oscillatory flow was reversed. The mixing performance was quantified by applying virtual particle tracing, setting up a virtual boundary surface, and following the changes in its area over time. The area increased exponentially, confirming the chaotic mixing characteristics.