Chemical Engineering & Technology最新文献

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.

In recent years, numerous innovative approaches have emerged to enhance the corrosion resistance of materials. This study investigates the effect of enhancing mild steel corrosion through the incorporation of unzipped multiwalled carbon nanotube oxides (UMCNO) into epoxy resin. Additionally, the effect of various operating parameters, such as temperature, UMCNO concentration, salt concentration, duration of exposure, and coating thickness, have also been considered in the study. The Box–Behnken method was used for experimental design and correlation of corrosion rate with various operating parameters, followed by analysis of variance of both five- and three-parameter models. Notably, despite variations in temperature and salt concentration, the corrosion rate remained negligible, confirming its suitability in various marine conditions. Furthermore, it was observed that the corrosion rate of mild steel coated with epoxy decreased with the addition of UMCNO. A corrosion rate of 0.182 mpy was observed for epoxy resin incorporated with 0.5 % UMCNO over a 14-day period, which is lower compared to other conditions. Electrochemical impedance spectroscopy and potentiodynamic polarization analysis showed higher corrosion-resistant properties in epoxy coating incorporated with UMCNO. In addition, it was evident from the contact angle measurement that the corrosion rate of mild steel was highly dependent on the concentration of UMCNO.

In this study, NiFe₂O₄, ZnFe₂O₄, and MgFe₂O₄ catalysts are utilized to decompose plastic into hydrogen gas, liquids, and carbon nanotubes. Ferrite nanoparticles worked as a catalyst and heat susceptors for microwaves. MgFe₂O₄ catalyst resulted in highly structured carbon residue with fewer impurities than other catalysts. The oil yield of 13.5, 14, and 9.5 wt. % was obtained with NiFe₂O₄, ZnFe₂O₄, and MgFe₂O₄, respectively. Similarly, gas evolution was about 14, 13, and 12.5 wt. %, respectively. MgFe₂O₄ displayed superior H₂ production efficiency of 90 % compared to the other two catalysts. These findings suggest high activity of MgFe₂O₄ catalyst compared to NiFe₂O₄ and ZnFe₂O₄ catalysts. This catalyst also showed stronger magnetic characteristics and reactivity.

Metallic alloy fuels from fast reactors will be reprocessed by a non-aqueous electrochemical technique known as electrorefining. Electrorefining of spent metal fuel results in the accumulation of heat-generating fission products, especially ¹³⁷Cs in the eutectic salt. These fission products need to be removed from the salt so as to reduce the decay heat load and contamination. The melt crystallization technique is a simple separation process being pursued for the separation of fission products. This is a single-step process that utilizes the difference in solubility of fission products in the solid and liquid phase. This process is also less energy intensive. Crystallization involves the purification of a substance from a liquid mixture by solidification of the desired component. Since separation is based on selective solidification, which involves phase change, it is essential to evaluate the transient solidification pattern, liquid fraction distribution, solute distribution, and separation time and efficiency. Numerical modeling of the separation of CsCl from a LiCl-KCl eutectic mixture has been carried out using Ansys Fluent (19.2). The effect of crystallizer geometry and cooling rates on the separation of CsCl has been numerically simulated.