Bio-syngas Conversion by FT Synthesis with High Loaded Fe-based Catalysts: Kinetic Parameters Regression

Biomass-to-liquid Fischer-Tropsch (FT) is an industrial process that converts bio-syngas in hydrocarbons ranging from C1 to C100. Bio-syngas, a syngas mixture produced from biomass, is characterized by a H2/CO molar ratio in the range 1.0–1.5. An iron-based catalyst supported on silica for CO hydrogenation with 30 wt% of metal was prepared, characterized by BET, SEM, TEM, TPR, XRD and tested at different temperatures and H2/CO ratios in a FT bench scale plant using a Packed Bed Reactor (PBR). The experimental results demonstrated that this catalyst is suitable for low H2/CO ratios, since by increasing the inlet H2/CO ratio the CO conversion increases, the product selectivity remains largely unchanged. Moreover the catalyst shows a satisfactory stability as a function of time of stream (TOS). A nonlinear regression was performed based on a selected kinetic model in order to obtain the main kinetic parameters. The elaborated kinetic model is based on the hypothesis that both FT and Water Gas Shift (WGS) reactions are active on the catalyst. Initially the regression was performed using MATLAB®, but the algorithm could not lead to an acceptable solution because of the high number of local minima presented by the objective function. In order to overcome this problem, a procedure in C++ has been developed. Respect to the model found in the literature, this new one has been rearranged for minimizing the multicollinearities between the optimized parameters and a satisfactory fitting respect the experimental values has been achieved. Based on the experimental collected data and the regressed parameters, a rigorous multi-scale simulation of reactor behaviour was developed in order predict the reactor yield and conversion

Biosyngas conversion by fischer-tropsch synthesis: experimental results and multi-scale simulation of a pbr with high fe loaded supported catalysts

Bio-syngas, i.e. the syngas mixture produced from biomass, is mainly characterized from a H2/CO molar ratio in the range 1.0-1.5, different from those of traditional syngas equal to 2. By feeding directly this mixture in a catalytic reactor for Fischer-Tropsch synthesis, iron based catalysts are more suitable with respect to the cobalt-based one. These catalysts are used industrially in their massive form. The possibility to use supported Fe-based catalysts are recently deeply considered in order to improve the surface area and the mechanical stability of the samples. In particular high Fe loaded supported catalysts are required to achieve satisfactory performance. Iron-based catalysts supported on silica for CO hydrogenation with 30%wt of metal have been prepared, characterized by BET, SEM, TEM, TPR, XRD and tested at different temperature and H2/CO ratio in a FT laboratory plant using a Packed Bed Reactor. On the basis of the collected data, a multi-scale simulation of the FT synthesis reactor has been developed considering that on the catalyst surface the reaction both of FT and Water Gas Shift are simultaneously activated. The experimental results demonstrated that by increasing the inlet H2/CO ratio, the CO conversion can be increased while preserving the products selectivity and confirm that FT are suitable also for low H2/CO ratio; furthermore the model elaborated agree with the experimental data obtained

Vegetable Oil Deacidification by Methanol Heterogeneously Catalyzed Esterification in (Monophasic Liquid)/Solid Batch and Continuous Reactors

The removal of free fatty acids (FFA) in vegetable oils is an important pretreatment in the production of biodiesel, in particular, when the starting materials are low-cost feedstocks. Heterogeneously catalyzed esterification with methanol transforms FFA in fatty acid methyl ester (FAME), decreasing the oil acidity and producing biodiesel simultaneously. The equilibrium of this reaction shifts toward the desired product when increasing the methanol content, but at the same time, a double-liquid-phase system forms when the methanol content is higher than 6-8 wt %. The presence of a double liquid phase can be an important drawback in the reactor. A detailed study about the optimization of the methanol quantity is presented, both using a batch and a packed-bed reactor (PBR) at different temperatures (between 60 and 105 degrees C) using Amberlyst 46 (ion-exchange resin) as the heterogeneous catalyst. The deacidification of sunflower oil in a monophasic liquid system leads to satisfactory results (final FFA lower than 0.5 wt %) for both of the reactors. The experimental results demonstrate that the excess of methanol is not convenient in terms of both slower reaction rates and mass of reactant used. The stability of Amberlyst 46 in the PBR was positively verified after 600 h of work

Production of oxygen-enriched air via desorption from water: Experimental data, simulations and economic assessment

Oxygen enriched air with a composition of oxygen till 35% can be produced by water desorption by simple water degassing. This work reports the simulation of a small bench-scale plant for the continuous production of oxygen-enriched air by simple water degassing. The basic thermodynamic principle involved is the higher water solubility of oxygen compared to the one of nitrogen. Different experiments were performed in a continuous small bench-scale plant changing the main operating parameters, i.e. water temperature, degasser pressure and the water flowrate in order to develop rigorous and reliable simulations with suitable software (PRO/II 9.3 by SIMSCI-Schneider Electric). The results obtained showed a good fitting between the experiments and the simulations and demonstrated the possibility for the production of enriched air using this new technology. Moreover, the calculation of the economic potentials of this new process were carried out, and the results compared to the already existing technologies

Flow-mediated dilation normalization predicts outcome in chronic heart failure patients.

Background: Reduced flow-mediated dilation (FMD) is a known prognostic marker in heart failure (HF), but may be influenced by the brachial artery (BA) diameter. Aiming to adjust for this influence, we normalized FMD (nFMD) by the peak shear rate (PSR) and tested its prognostic power in HF patients. Methods and Results: BA diameter, FMD, difference in hyperemic versus rest brachial flow velocity (FVD), PSR (FVD/BA), and nFMD (FMD/PSR × 1000) were assessed in 71 HF patients. At follow-up (mean 512 days), 19 HF (27%) reached the combined endpoint (4 heart transplantations [HTs], 1 left ventricle assist device implantation [LVAD], and 14 cardiac deaths [CDs]). With multivariate Cox regression analysis, New York Heart Association functional class ≥III (hazard ratio [HR] 9.36, 95% confidence interval [CI] 2.11-41.4; P =.003), digoxin use (HR 6.36, 95% CI 2.18-18.6; P =.0010), FMD (HR 0.703, 95% CI 0.547-0.904; P =.006), PSR (HR 1.01, 95% CI 1.005-1.022; P =.001), FVD (HR 1.04, 95% CI 1.00-1.06; P =.02), and nFMD (HR 0.535, 95% CI 0.39-0.74; P =.0001) were predictors of unfavorable outcome. Receiver operating characteristic curve for nFMD showed that patients with nFMD >5 seconds had significantly better event-free survival than patients with nFMD ≤5 seconds (log-rank test: P 5 seconds have a better prognosis than those with lower values

Call and be counted! Can we reliably estimate the number of callers in the indri's (<i>Indri indri</i>) song?

<div><p>Estimating the number of animals participating in a choral display may contribute reliable information on animal population estimates, particularly when environmental or behavioral factors restrict the possibility of visual surveys. Difficulties in providing a reliable estimate of the number of singers in a chorus are many (e.g., background noise masking, overlap). In this work, we contributed data on the vocal chorusing of the indri lemurs (<i>Indri indri</i>), which emit howling cries, known as songs, uttered by two to five individuals. We examined whether we could estimate the number of emitters in a chorus by screening the fundamental frequency in the spectrograms and the total duration of the songs, and the reliability of those methods when compared to the real chorus size. The spectrographic investigation appears to provide reliable information on the number of animals participating in the chorusing only when this number is limited to two or three singers. We also found that the Acoustic Complexity Index positively correlated with the real chorus size, showing that an automated analysis of the chorus may provide information about the number of singers. We can state that song duration shows a correlation with the number of emitters but also shows a remarkable variation that remains unexplained. The accuracy of the estimates can reflect the high variability in chorus size, which could be affected by group composition, season and context. In future research, a greater focus on analyzing frequency change occurring during these collective vocal displays should improve our ability to detect individuals and allow a finer tuning of the acoustic methods that may serve for monitoring chorusing mammals.</p></div

Indri’s song duration.

<p>The indris’ song duration is (A) presented as a function of Group size (dashed line), Real chorus size (solid line), and Predicted chorus size (dotted line). The Real chorus size is presented as a function of (B) the Acoustic complexity index (ACI) and (C) the Acoustic entropy index (H). Each regression line is represented with the associated 95% confidence interval range (shades). Error bars indicate standard errors.</p

Tortietal2018: Complete Data Table of the Indri Songs

Torti et al. The sound of silence. Can we reliably estimate the number of callers in a chorus? PlosONE.<div><br></div><div>Table reports the file name, group ID, real number of singers, unsupervised estimate of the number of singers, group size, song duration, Acoustic Diversity Index, Acoustic Complexity Index, Acoustic Entropy Index, and Acoustic Richness Index.</div