Simulation of Organic Liquid Product Deoxygenation through Multistage Countercurrent Absorber/Stripping Using CO2 as Solvent with Aspen-HYSYS: Process Modeling and Simulation

In this work, the deoxygenation of organic liquid products (OLP) obtained through the thermal catalytic cracking of palm oil at 450 °C, 1.0 atmosphere, with 10% (wt.) Na₂CO₃ as a catalyst, in multistage countercurrent absorber columns using supercritical carbon dioxide (SC-CO₂) as a solvent, with an Aspen-HYSYS process simulator, was systematically investigated. In a previous study, the thermodynamic data basis and EOS modeling necessary to simulate the deoxygenation of OLP was presented. This work addresses a new flowsheet, consisting of 03 absorber columns, 10 expansions valves, 10 flash drums, 08 heat exchanges, 01 pressure pump, and 02 make-ups of CO₂, aiming to improve the deacidification of OLP. The simulation was performed at 333 K, 140 bar, and (S/F) = 17; 350 K, 140 bar, and (S/F) = 38; 333 K, 140 bar, and (S/F) = 25. The simulation shows that 81.49% of OLP could be recovered and that the concentrations of hydrocarbons in the extracts of absorber-01 and absorber-02 were 96.95 and 92.78% (wt.) on a solvent-free basis, while the bottom stream of absorber-03 was enriched in oxygenated compounds with concentrations of up to 32.66% (wt.) on a solvent-free basis, showing that the organic liquid products (OLP) were deacidified and SC-CO₂ was able to deacidify the OLP and obtain fractions with lower olefin contents. The best deacidifying condition was obtained at 333 K, 140 bar, and (S/F) = 17.

Simulation of Organic Liquid Products Deoxygenation by Multistage Countercurrent Absorber/Stripping Using CO2 as Solvent with Aspen-HYSYS: Thermodynamic Data Basis and EOS Modeling

In this work, the thermodynamic data basis and equation of state (EOS) modeling necessary to simulate the fractionation of organic liquid products (OLP), a liquid reaction product obtained by thermal catalytic cracking of palm oil at 450 °C, 1.0 atmosphere, with 10% (wt.) Na₂CO₃ as catalyst, in multistage countercurrent absorber/stripping columns using supercritical carbon dioxide (SC-CO₂) as solvent, with Aspen-HYSYS was systematically investigated. The chemical composition of OLP was used to predict the density (ρ), boiling temperature (T_b), critical temperature (T_c), critical pressure (P_c), critical volume (V_c), and acentric factor (ω) of all the compounds present in OLP by applying the group contribution methods of Marrero-Gani, Han-Peng, Marrero-Pardillo, Constantinou-Gani, Joback and Reid, and Vetere. The RK-Aspen EOS used as thermodynamic fluid package, applied to correlate the experimental phase equilibrium data of binary systems OLP-_i/CO₂ available in the literature. The group contribution methods selected based on the lowest relative average deviation by computing T_b, T_c, P_c, V_c, and ω. For n-alkanes, the method of Marrero-Gani selected for the prediction of T_c, P_c and V_c, and that of Han-Peng for ω. For alkenes, the method of Marrero-Gani selected for the prediction of T_b and T_c, Marrero-Pardillo for P_c and V_c, and Han-Peng for ω. For unsubstituted cyclic hydrocarbons, the method of Constantinou-Gani selected for the prediction of T_b, Marrero-Gani for T_c, Joback for P_c and V_c, and the undirected method of Vetere for ω. For substituted cyclic hydrocarbons, the method of Constantinou-Gani selected for the prediction of T_b and P_c, Marrero-Gani for T_c and V_c, and the undirected method of Vetere for ω. For aromatic hydrocarbon, the method of Joback selected for the prediction of T_b, Constantinou-Gani for T_c and V_c, Marrero-Gani for P_c, and the undirected method of Vetere for ω. The regressions show that RK-Aspen EOS was able to describe the experimental phase equilibrium data for all the binary pairs undecane-CO₂, tetradecane-CO₂, pentadecane-CO₂, hexadecane-CO₂, octadecane-CO₂, palmitic acid-CO₂, and oleic acid-CO₂, showing average absolute deviation for the liquid phase (AADx) between 0.8% and 1.25% and average absolute deviation for the gaseous phase (AADy) between 0.01% to 0.66%.

Inter- and Intra-Individual Analysis of Post-Exercise Hypotension Following a Single Bout of High-Intensity Interval Exercise and Continuous Exercise: A Pilot Study

Recently, post-exercise blood pressure (BP) has been considered a predictive tool to identify individuals who are responsive or not to BP reductions with exercise training (i. e., "high" and "low responders"). This study aimed to analyze the inter- and intra-individual BP responsiveness following a single bout of high-intensity interval exercise (HIIE) and continuous exercise (CE) in normotensive men (n=14; 24.5±4.2 years). Mean change in BP during the 60 min period post-exercise was analyzed and minimal detectable change (MDC) was calculated to classify the subjects as "low" (no post-exercise hypotension [PEH]) and "high responders" (PEH occurrence) following each exercise protocol (inter-individual analysis). The MDC for systolic and diastolic BP was 5.8 and 7.0 mmHg. In addition, a difference equal/higher than MDC between the exercise protocols was used to define an occurrence of intra-individual variability in BP responsiveness. There were "low" and "high" PEH responders following both exercise protocols (inter-individual variability) as well as subjects who presented higher PEH following a specific exercise protocol (intra-individual variability between exercise protocols). These results were observed mainly for systolic BP. In summary, PEH is a heterogeneous physiological phenomenon and, for some subjects, seems to be exercise-protocol dependent. Further investigations are necessary to confirm our preliminary findings.

Is the mouse follicle culture a good model for the goat with respect to the development of preantral follicles in vitro?

The present study evaluated the efficiency of using 2 culture media developed for mice and for goats in the in vitro preantral follicle culture of each species. Murine and caprine secondary follicles were cultured in vitro with human recombinant follicle-stimulating hormone (murine medium) or with bovine recombinant follicle-stimulating hormone in association with growth hormone (caprine medium). The results showed that murine follicles cultured in caprine medium had lower (P < 0.05) rates of follicular survival and growth, whereas for caprine follicles, these variables were not affected by the type of medium used (P > 0.05). After in vitro maturation, a higher (P < 0.05) number of oocytes that resumed meiosis were observed in the murine medium for both species. In contrast, only in the caprine species estradiol production was significantly superior when the caprine medium was used. Higher progesterone production was observed in the presence of the murine medium only for murine follicles (P < 0.05). In conclusion, murine and caprine preantral follicles cultured under the same in vitro culture medium conditions respond differently; caprine oocytes grown in vitro in the presence of the murine medium show the greatest developmental competence among the tested combinations. Therefore, under the present experimental conditions, the mouse follicle culture has proved be a good model for the development of new culture media for caprine preantral follicles.