The production processes of dimethyl carbonate (DMC) typically involve an excess amount of methanol, and therefore, the separation of DMC from methanol is essential in the chemical industry. While pressure swing distillation is commonly used for this separation, it is an energy-intensive process. Pervaporation, on the other hand, has been found to be a more energy-efficient method, especially when a suitable inorganic or ceramic membrane is used. The use of polymeric membranes is not recommended due to the high operating temperatures required. Hybrid silica membranes, such as HybSi®, have emerged as a promising option for this purpose. In this study, we conducted both laboratory and pilot-scale pervaporation experiments along with pilot-scale pervaporation-assisted distillation experiments, and carried out process simulations to evaluate the potential cost savings in DMC purification using a HybSi® membrane. The cost of purification was calculated per ton of DMC produced, and results demonstrated cost savings compared to the base case using pressure swing distillation. These savings were attributed to reduced operating and capital expenditures resulting from lower energy consumption and a more compact design. Our results indicate that the use of HybSi® membranes has the potential to revolutionize the DMC production process and provide a more sustainable and cost-effective solution.

Abstract Refrigeration effects lower than − 20°C can be traditionally achieved using a vapor-recompression refrigeration cycle with various refrigerants having their own supply temperatures. In this study, the values contained in the liquefied natural gas (LNG) cold heat have been estimated when more than 30 pure refrigerants are liquefied by exchanging heat with LNG instead of using a vapor-recompression refrigeration cycle. There was a total of 35 selected refrigerants for evaluation of cold heat price contained in LNG, which includes n-butane, propane, propylene, ammonia (NH3), 1,1,1,2-tetrafluoroethane (R-134a), hydrochlorofluorocarbon (R-22) etc. Simulation works have been carried out for each single refrigeration cycle using the Peng-Robinson equation of state in combination with TWU’s alpha function. PRO/II with PROVISION V2021, a steady-state simulation tool from Aveva Company, was used to model the refrigeration cycle and LNG cold heat value estimation. It was concluded that the estimated values of the LNG cold heat were inversely proportional to refrigerant supply temperature since the compressor power is proportionally increasing when the refrigerant supply temperature is lower and vice versa.

The vaporization of liquefied carbon dioxide (LCO 2 ) resulting from heat transfer in undersea pipeline flow was examined in this feasibility study. The purpose of the study was to assess how several factors, including flow velocity, temperature and height, affected the rate at which CO 2 evaporated in a submerged pipeline. Ansys Fluent and Aspen Plus were two of the simulation tools used for the analysis. For the assessment, the SRK thermodynamic model was chosen. Start-up, shutdown, and abnormal dynamic studies were further conducted to ascertain the safe operation of the pipeline using Aspen Plus and Aspen Dynamics. The study emphasizes the need to take heat transfer into account in the design and operation of these pipelines and offers insightful information about the behavior of CO 2 in undersea pipelines. Reliable seabed and oceanographic data were obtained with the corresponding temperatures for the prediction of pipeline landfall. The maximum pressure of 76.61 barg was established at Node 11 but further drop at the last 200m pipe segment (N11 to N13) to achieve an outlet pressure of 59.72 barg. The loss of pressure was due to gravity since the fluid was directed upward to the sea platform. There was a gradual drop in temperature along the pipeline. The temperature at the pipe outlet was calculated to be 3.33 o C. The results of this study can be applied to improve efficiency and lower the risk of accidents associated with the design and operation of underwater pipelines for the transportation and storage of CO 2 . The results in this work is significant since it offers a thorough grasp of how CO 2 behaves in submerged pipes, knowledge that may be utilized to guarantee the effective and safe transit and storage of this material.

The hydrogen fuel filling time for hydrogen-powered fuel cell electric vehicles at different initial conditions was estimated through dynamic simulation by using Aspen Dynamics v.11 with Peng-Robinson as the thermodynamic model. The simulation process was divided into three parts, in which the different storage vessels (LP, MP, and HP banks) act as the sole hydrogen source. The SAE J2601 standard was used as the basis for the fueling operation. For the fast filling of the car tank with hydrogen gas, a detailed heat transfer modeling suited for the process was elaborated to correctly predict the in-cylinder temperature throughout the fueling operation. During the dynamic simulation, the station pressure, the state-of-charge %, the car tank temperature, the hydrogen flow rate, the amount of hydrogen gas accumulated in the car tank, and the high-pressure storage vessels’ conditions were monitored and confirmed according to their expected values or limits. It is determined that the fueling times calculated in the dynamic study were faster than their corresponding estimated values for all cases, indicating the integrity of the process.

The separation of methanol-chloroform mixture, a minimum-boiling azeotrope, is performed using pressure- swing distillation process via process simulation. In this study, the steady-state optimization was carried out using PRO/II with PROVISION v.10. The two different column configurations (low-to-high pressure and high-to-low pressure) were compared wherein the positions of the low-pressure column and high-pressure column were operated interchangeably to attain an optimized design. Additionally, different heat-integration configurations (partial heat- and full heat-integration) were applied to lessen the overall utility consumption. It was determined that the low-to-high pressure column configuration provided a more optimized result for all heat-integrated systems as compared to high-tolow pressure column configuration. Application of heat-integration further decreases the cooling water and steam consumption by 38.86% and 35.74%, respectively, for partial heat-integrated system, and by 44.58% and 41.01%, respectively, for full heat-integrated system.

This study was conducted to establish the relationship of a multiple regression analysis between anaerobic exercise ability, health fitness and wellness domain of dancers. Data were collected by surveying 110 dancers from middle and high schools, universities, and graduate schools after identifying the sample. One Gate, a TestWell survey, measures anaerobic exercise capacity using Wingate Anaerobic peak power [PP], Average Power [AP], Fatigue Index [FI]), cardiovascular endurance (PEI), flexibility, body composition, body fat mass (BFM), body mass index (BMI), percentage body fat (PBF), lean body mass (LBM), and cellular water. For statistical analysis, the study used t-test, one-way ANOVA, Fishers Least Significant Difference (LSD) test, Simple Linear Regression, and Multiple Linear Regression. As a result of the investigation and analysis of this research, it turned out that there is a significant (p＜.05) causal relationship between physical domain and dancing career, body fat, percentage body fat, and body mass index. In conclusion, through the collected data, it is possible to manage and prevent diseases using big data. The intention of this research is to propose a utilization method by providing knowledge in dance medicine field through diagnosis, treatment and prevention with an analysis of clustered information.

The present study was conducted to identify the correlation between fitness and wellness across dancers’ types of dance. Data were collected by surveying 110 dancers from middle and high schools, universities, and graduate schools after identifying the sample. One Gate, a TestWell survey, measures anaerobic exercise capacity using Wingate Anaerobic peak power [PP], Average Power [AP], Fatigue Index [FI]), cardiovascular endurance (PEI), flexibility, body composition, body fat mass (BFM), body mass index (BMI), percentage body fat (PBF), lean body mass (LBM), and cellular water. For statistical analysis, the study used t-test, one-way ANOVA, Fishers Least Significant Difference (LSD) test, Simple Linear Regression, and Multiple Linear Regression. The results of investigation and analysis in this study found no statistically significant difference between three types of dance (ballet, Korean and modern) in all factors in the Wingate anaerobic power test: peak power (PP), average power (AP), and fatigue index (FI). A statistically significant difference was revealed between the three types of dance in the physical efficiency index among other health and fitness factors (p.05). An analysis of wellness questionnaires found that ballet, Korean, and modern dancers showed a statistically significant difference on the spiritual and emotional dimension (p.05). On the safety and self-care dimension, a statistically significant difference was also observed between ballet, Korean, and modern dancers (p.05).BR In conclusion, the present study aims to develop a model based on the above results and provide high-quality disease prediction data that could alleviate the link between causes of injury to dancers and health and wellness.

This study investigated changes in body composition, energy balance, and appetite-regulating hormones in professional female ballet dancers before and after 3 days of ballet performances. The subjects were 43 professional female ballet dancers in Korea. The mean age of the subjects was 25.9 ± 2.8 years, and they had over 13 years of ballet training on average. For body composition, the body mass index (BMI), percent body fat (%BF), lean body mass (LBM), and total body water (TBW) were evaluated. By way of blood analysis the serum levels of ghrelin, leptin, and insulin were examined. The calculations of energy intake (EI) and expenditure (EE) were based on journals that were self-recorded by the subjects for 14 days. For statistical analysis, the dependent sample t-test was applied (p < 0.05). The results showed no significant change in %BF, but the BMI, LBM, and TBW increased significantly in the post-performance measurement. Energy balance results demonstrated a significant increase in EI and decrease in EE. Both the ghrelin and leptin levels increased significantly. Although reported energy intake increased after performances, it remained below estimated energy requirements. Ballet dancers should be aware of the need to maintain energy balance in order to optimize their health and performance.

Extractive distillation is an alternative for processes where normal distillation is difficult, such as separation of close-boiling mixtures, but solvent selection for distillation is laborious, and its selection pool is narrow. An innovative selection process using molecular simulation is proposed, and the performance of the selected solvent, 1,2,4-trichlorobenzene, for the separation of 1,2,4-trimethylbenzene from a C9 mixture is reviewed. The proposed process requires less investment and leads to lower operating expenses than the conventional two-column process. The computed vapor-liquid equilibrium determined from the molecular simulation is close to the HYSYS estimation in two ternary systems.

In order to solve the global warming and reduce greenhouse gas emissions, it has been developed the CO2 capture technology by oxy-fuel combustion. But there is a problem that the economic efficiency is low because the oxygen production cost is high. ASU (Air Separation Unit) is known to be most suitable method for producing large capacity of oxygen (>2,000 tpd). But most of them are optimized for high purity (>99.5%) oxygen production. If the ASU process is optimized for low purity(90 similar to 97%) oxygen producing, it is possible to reduce the production cost of oxygen by improving the process efficiency. In this study, the process analysis and comparative evaluation was conducted for developing large capacity ASU for oxy-fuel combustion. The process efficiency was evaluated by calculating the recovery rate and power consumption according to the oxygen purity using the AspenHysys. As a result, it confirmed that the optimal purity of oxygen for oxyfuel combustion is 95%, and the power consumption can be reduced by process optimization to 12 similar to 18%.