Theoretical Foundations of Chemical Engineering最新文献

The pressure effect on the relative volatility of binary mixtures of different natures and ternary mixtures containing potential separating agents such as dimethylsulfoxide (DMSO) and butyl propionate is studied. A wide range of information is obtained based on the data on the vapor–liquid equilibrium, and effects of the pressure on the relative volatility of various nature and cause for a fixed composition of the initial mixture are determined. In the presence of intersection points of the phase-equilibrium curves in the initial binary mixture and pseudobinary mixture (in the section with a constant concentration of the third high-boiling component), the concentration simplex is divided into regions in which the values of the relative volatility decrease (increase) upon varying pressure. This fact makes it possible to improve the procedure of separation process optimization at the stage of operating pressure selection in the columns.

TiO₂/Au had been prepared readily from tetrabutyl titanate and chloroauric acid by in situ solvothermal method. SEM, XRD, UV-vis, FTIR, etc were used for characterizing the morphology, crystal structure, and optical performance of TiO₂ and TiO₂/Au. The photocatalytic degradation performance on methyl orange and antibacterial properties against Escherichia coli of TiO₂ and TiO₂/Au were studied. The results showed that the TiO₂/Au both possessed superior photocatalytic properties under simulated or nature sunlight. The photocatalytic degradation rate of TiO₂/Au on methyl orange was up to 91.57% that was obviously better than TiO₂ (65.13%). Moreover, TiO₂ and TiO₂/Au had significant antibacterial properties against Escherichia coli, and the inhibition rate was up to 99.89%. The activity of TiO₂ and TiO₂/Au was tested by ESR and H₂-TPR for analyzing the mechanism of the improvement of the photocatalytic activity and antibacterial properties.

Physicochemical and pharmacokinetic properties represent the fundamental properties of drugs and affect their bioavailability. In this work, these properties are calculated and used to determine the preference of selected tautomers. 2-pyridones are nitrogen-containing heterocyclics that play an important role in drug design. All the Hydroxpyridone (HPYR)/ pyridone (PYR) tautomers studied in this work are lipophilic molecules. We also conclude that HPYRs are more lipophilic (more soluble in n-octanol) than PYRs. The bioavailability of the studied compounds was determined using ADMET analysis. The results showed that most of the 2-pyridones derivatives can be used orally and do not exhibit neurotoxicity effects. We also studied the tautomerization of 2-pyridones which can be done by two possible mechanisms, the classical pathway and dimerization in different phases. The calculations were carried out in the gas phase and in solution using quantum chemistry methods.

The objective of this work is to test the capability of the first order kinetic model and Gompertz model to describe the volume of biogas produced by anaerobic digestion of organic solid waste versus time. The test was done by two ways: first, by using data obtained experimentally form the codigestion of Prosopis Juliflora sawdust with camel, chicken, cow manure and wastewater sludge at 37^oC for a period of 60 days and second by using experimental data available in open literature. The adequacy of the models was assessed by calculating R² and the residual sum of squares (RSS). The results showed that Gompertz model is more successful in representing the volume versus time data. The first order kinetic model was not capable of doing so for most of the cases studied. Codigestion of Prosopis Juliflora sawdust with animal manure showed that codigestion with chicken manure gave the highest amount of biogas whereas codigestion with camel manure gave the lowest amount of biogas. The amount of biogas produced upon codigestion of Prosopis Juliflora sawdust with animal manure follow the following order: P. Juliflora + chicken manure > P. Juliflora + wastewater sludge > P. Juliflora + cow manure > P. Juliflora + camel manure.

Converter steelmaking is a key part of steel production, and the resulting converter gas contains a large amount of CO₂. CO₂ capture of converter gas can benefit the reduction of CO₂ emissions in the steel industry. In this study, a post-combustion capture process based on monoethanolamine (MEA) was established in Aspen Plus, and the absorption and desorption performance of MEA on converter gas were investigated by simulation using the thermodynamic model of ELECNRTL. Increasing the depletion flow rate, temperature, and MEA concentration can help to improve the CO₂ capture rate; the feed position and desorption pressure affect the CO₂ desorption effect, and the best desorption effect is achieved when the feed position is the second tray, and the desorption tower pressure is 1.9 bar. The results of the study can provide a new idea for CO₂ capture at the end of converter steelmaking, which is of great significance for the progress of CCUS technology in the iron and steel industry.

The research of optimal compromise operation modes of five-column rectification unit, designed for isopropyl benzene extraction from benzene alkylation products by propylene, at variation of feed rate to the head tower is performed. We selected two optimization criteria in the form of productivity by outlet flow from the considered system of columns with the given concentration of isopropylbenzene and energy consumption for creation of steam flow in the columns. We varied feed flow rate to the head-column. Analysis of obtained results of the step-by-step approach for determining the optimal trade-off solution made it possible to establish that the multidimensional function of achieving a trade-off solution for the entire installation is unimodal. This result justifies the application of multidimensional extremum search methods to solve the problem of obtaining the optimal compromise solution. It has been established that the dependences of control variables on the supply flow rate to the head tower are linear when the optimum compromise modes are achieved.

The frequency of carbon fuel consumption is extremely high and rising quickly, ultimately increasing the air pollution level. Due to increasing environmental pollution levels, researchers are looking for greener, cleaner alternatives to diesel fuel for diesel engines. This study concentrated on the synthesis, characterization, and consequences of Brassica napus biodiesel on diesel engine performance and emissions. Brassica napus biodiesel has the same necessary physicochemical properties as diesel fuel. Then, a diesel engine was used to compare diesel fuel emissions and performance parameters with Brassica napus biodiesel. According to the research results, B10 fuel from Brassica napus biodiesel performs better than straight diesel fuel. The effective concentration of biodiesel in diesel blends was increased by adding nano additives to a specific amount of biodiesel blends. This study examined the effects of nano-Al₂O₃ additions on the B20 mix of Brassica napus biodiesel in single-cylinder direct-injection diesel engines. Biodiesel blends complete combustion and inherent oxygen, significantly lowering emissions than standard diesel. The B20 blend of Brassica napus biodiesel has demonstrated a higher overall performance. The biodiesel blend using the Nano additives showed a notable reduction in emissions.