The phase diagrams, densities, and refractive indices of a ternary system comprising polyethylene glycol (PEG) 1000, potassium chloride, and water at 288.2, 298.2, and 308.2 K were determined. Only one liquid phase was obtained for the KCl–PEG1000 (PEG of molecular weight 1000)–H₂O ternary system over the entire PEG1000 composition range studied. The results revealed that the solubility of KCl increased with an increase in temperature at constant PEG concentration. Conversely, at constant temperature, the solubility of KCl decreased with an increase in PEG1000 in the solution. Moreover, the density of the solution decreased with the addition of PEG1000 in the solution, while the refractive index increased with the increase in PEG1000. The equilibrium thermodynamics of the KCl–PEG1000–H₂O system at 288.2, 298.2, and 308.2 K were calculated from the modified Pitzer equation. Finally, a comparison of the experimental and calculation diagrams revealed that the predictive solubilities agree well with the experimental values.

Enhancing the performance of existing distillation columns has received considerable attention from the chemical process industry; however, success depends strongly on the optimization step. The authors propose a practical method employing a particle swarm optimization (PSO) methodology for optimal retrofitting of existing distillation columns. The PSO algorithm allows a problem with multiple potential solutions to be solved by moving the particles around the search space via simple PSO methodology formulations. MATLAB was used to implement the algorithm and was then connected to an HYSYS model. Two industrial cases were examined in distillation retrofit optimization of the separation sequence for zeotropic and azeotropic mixtures to evaluate the efficiency of the PSO methodology. The results show that the methodology is competitive with conventional optimization techniques such as the response surface methodology, coordinate descent methodology, and genetic algorithm. Not only the structural variables but also the operating variables are simply and effectively optimized. Notably, the operating cost savings were calculated as 34.2% and 12.8% for ethylene dichloride purification and acetone–methanol separation processes, respectively. Furthermore, the reduction of carbon dioxide emission was investigated after retrofitting distillation sequences.

Homogenous acid catalysts are often used in industries producing acrylate esters. The separation of these catalysts from the reaction medium is difficult, in addition to their toxicity and corrosiveness. The heterogeneously catalyzed esterification that uses the poly(styrene-divinylbenzene) sulfonated resin as catalyst can overcome the drawbacks of homogeneous catalysts. In the present work, the activity and kinetic studies of a batch-wise esterification of acrylic acid (AA) and 2-ethylhexanol (2EH) catalyzed by DIAION acidic ion exchange resins were carried out. DIAION resin PK208 out-performed the other resins due to its comparative ion exchange capacity and low percentage of cross-linkage that enhance the accessibility of the reactant. PK208 was used subsequently in the kinetic studies. The highest yield of 2-ethylhexyl acrylate (2EHA) achieved was 41% after 4 h reaction at an initial reactant molar ratio of AA to 2EH of 1 : 3, catalyst loading of 10 wt% and temperature of 388 K. Eley–Rideal (ER) was the best kinetic model to correlate the production rate of 2EHA. Endothermicity of the AA esterification with 2EH was indicated by the increase of its equilibrium constant with temperature.

Quantitative Risk Analysis (QRA) in the hazardous process industry has been utilized by national safety organizations and business operators as a very valuable tool for obtaining numerical estimates of risk effectively. However, QRA has a complex and difficult analysis process, and this sets a limitation on the implementation of the risk management principles, that is, participation and communication of various stakeholders on the overall risk analysis stages repetitively. In addition, QRA requires a long period of analysis time, and this makes it even more difficult to be used as a prompt decision-making tool in changes of safety policies and external environment. Therefore, this paper suggests an analysis framework that supports a collaborative QRA to overcome such limitations and a quantitative risk management process model based thereon. This is based on the analysis pivot named ARHSP (Accidental Release Hazard Scenario Point), and ARHSP is characterized by the sharing of information and execution of co-operative work for quantifying the risk. In other words, ARHSP is a well-organized risk analysis unit that is set by experts in a way that analytical information can be reviewed and entered by internal stakeholders such as safety managers in the case of necessity, which makes division of work (cooperation) possible. Furthermore, the framework proposed in this paper is applied to the QRA system development of KOGAS, which is one of the largest LNG importers. Further, the effectiveness is validated by showing that relevant parties apply it to perform QRA collaboratively for three large LNG import terminals in a short-period compared to the time expected in a conventional way. Ultimately, this study demonstrates a practical framework to which organizations or enterprises can refer when they want to establish a relevant method or develop a system for activating efficient QRA application.

Yelang Lake, located in Puding County, China, is the main drinking-water source for Anshun City with a population of approximately 2.5 million. Sediment and water samples were collected from YeLang Lake and its input rivers, which flow across an abandoned lead and zinc mine. Thirteen kinds of heavy metals were analyzed in addition to conventional water quality index. The results showed that the lake water quality was good and could be used as a drinking water source after the mining activities were stopped 2 years before. However, the concentrations of heavy metals in sediments, especially Zn, Pb, Cd and As, remained at rather elevated values, posing a potential threat to the local aquatic environment. Concentrations of heavy metals in sediments increased with depth, and then decreased with peak concentrations appearing at 20–40 cm. This distribution pattern of heavy metals in sediments reflects the history of lead and zinc mining activities at the upstream of the studied lake. Regular monitoring of water quality must be strengthened to prevent environmental pollution incidents.

As core equipment of the wastewater treatment process in chemical enterprises, the inverted umbrella aerator has been well studied in the areas of structural design and performance improvement. However, the relations between two devices which are geometrically and dynamically similar are far from having been thoroughly researched. This paper aims at investigating the relationships between geometrically and dynamically similar aerators and establishing a general performance prediction model for them. Based on dimensional analysis, the effect of structure on aeration performance is formulated by dimensionless relational expressions using the experimental data of reduced-scale aerators (reduced-scale model), and thus the performance prediction mathematical model for other aerators with geometrical and dynamical similarities is established. The Froude number Fr is found to be the most important affecting parameter of the improved absorption number Y, which is the only dimensionless number characterizing aeration performance. Validation of the formulas is conducted through the comparison of predicted values and experimental data in two validation aerators whose scale differences to reduced-scale model are 33% and 66%, respectively. Finally, the maximum average relative error between predicted values and experimental data was 8.92%, which indicates that the formulas are reliable and applicable to the performance prediction of the scaled aerator through the data of its reduced-scale prototype.