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This work investigates the influence of temperature on the performance of hydrothermal carbonization of corn Stover between 175 and 250 °C, 240 min, 2.0 °C/min, and biomass-to-water ratio of 1:10. The performance analyzed for yields, energy densification and recovery. Aqueous phase analyzed for pH, acetic acid equivalent (HAc), HPLC, and GC, solid phase for dry and organic matter, ash, and elemental analysis. Solid yield (62.92–35.82%) increases with temperature, showing an inflection region between 200 and 225 °C, while that of liquid (35.43–54.59%) decreases in a similar behavior, and gas yield (1.49–9.59%) increases exponentially. GC identified alcohols, carboxylic acids, and furans. The concentration of furfural and Hidroxymethylfurfural (HMF) decreases exponentially and as a sigmoid with temperature, being not detectable at 250 °C. Carbon content increases, while oxygen and hydrogen decreases with temperature. The high heating values (HHV) increase, and the energy efficiency decreases with temperature. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the fractionation of fatty acids from palm oil deodorizer distillates, a by-product of the physical refining process of palm oil, has been investigated in a laboratory scale countercurrent packed column with supercritical CO2 as solvent. Experiments were carried out at 26 and 29MPa and 373K. Phase equilibria for the mixture palm fatty acids distillates+CO2 have been investigated experimentally by the static method at 333, 353, and 373K and pressures between 20 and 29MPa. The chemical identification of free fatty acids has been performed by gas chromatography. Hydrodynamic experiments were carried out for the systems palm fatty acids distillates+CO2 at 333, 353, and 373K and pressures between 20 and 29MPa in order to compute the column hydraulic capacity. A separation analysis based on phase equilibrium data (gas loading and selectivity) as well as hydrodynamic experiments (density of the coexisting liquid–gaseous phase and column hydraulic capacity) has been performed in order to optimize the best operation conditions. Process data (solvent and feed flow rates, reflux ratio, and mass fractions in feed and product streams) as well as phase equilibrium data of the multi-compound system fatty acids/carbon dioxide were used to compute the number of stages by the McCabe-Thiele and Jänecke methods. The mass transfer efficiency of the process was analyzed in terms of HETP as a function of liquid load, solvent-to-feed ratio and reflux ratio. HETP values lies between 0.8 and 2.5m. The results show that palmitic acid was enriched from an initial content of 52.51wt.% in the feed to 74.39wt.% in the extract, while the oleic+linoleic acids were enriched from 46.27wt.% in the feed to 59.00wt.% in the raffinate showing that countercurrent gas extraction using carbon dioxide as solvent is suitable for fractionation and enriching of fatty acids from palm fatty acids distillates. [Copyright &y& Elsevier]

Graphical abstract Highlights • Process simulation of deacidification of OLP by multistage gas extraction using CO 2 as solvent with Aspen-Hysis. • Best condition obtained at 333 K, 140 bar, S/F = 17 shows a yield of 36.65% with 96.95% hydrocarbons and 3.05% (wt.) oxygenates. • The oxygenates of OLP decrease from 10% (wt.), with 2.63% (wt.) FFA, to 3.05% (wt.) oxygenates, with 0.52% (wt.) FFA. • The results of simulations show that SC-CO 2 was able to deacidify OLP and to obtain fractions with lower olefins content. Abstract Fractionation of liquid phase products (OLP), obtained by thermal catalytic cracking of palm oil, simulated in multistage countercurrent absorber/stripping columns using SC-CO 2 as solvent with Aspen-Hysys, at 333 K, 140 and 180 bar, and (S/F) = 12, 15, 17, 25, 30, 38. RK-Aspen EOS applied to correlate equilibrium data of binary systems (OLP)-i/CO 2. Composition of OLP used to predict thermophysical properties and acentric factor of OLP compounds by group-contribution methods. The effect of pressure and (S/F) on process performance evaluated by computing the yield and recoveries of hydrocarbons, olefins, oxygenates, carboxylic acids. The regressions show that RK-Aspen EOS describe well phase equilibrium data, showing AAD between 0.8% and 1.25% and 0.01%– 0.66% for the liquid and gaseous phases. The best deacidifying conditions obtained at 333 K, 140 bar, and (S/F) = 17. Simulations show that SC-CO 2 was able to deacidify OLP and to obtain fractions with lower olefins content. [ABSTRACT FROM AUTHOR]

Abstract: In this work, enriching of anti-oxidants has been systematically investigated by supercritical adsorption process. The adsorption of buriti oil (Mauritia flexuosa Mart.) has been determined experimentally by the method of frontal analysis in columns packed with γ-alumina at 15, 20, and 25MPa, 333K, and solvent flow rate of , using an assemble of coupled columns of 81cm3, adopted to be used as an adsorption cell. The oil of buriti has been physical–chemically characterized according to AOCS official methods in terms of acid, saponification, peroxide and iodine values, refraction index, density and viscosity. Chemical composition of buriti oil in terms of fatty acid esters has been performed by GC and anti-oxidants activity by the method of free radical capture (DPPH). The adsorbent was characterized by X-ray fluorescence, X-ray powder diffraction, electron scanning microscopy, particle and pore size distribution, particle porosity and specific area. A material balance has been performed on the adsorption column to compute the cumulative mass of adsorbing species in γ-alumina on supercritical adsorption process by applying a pseudo-first order kinetic model as well as an integral kinetic model. The influence of pressure on the supercritical adsorption has been investigated by analyzing the mass transfer performance. A Langmuir type isotherm has been used to model the experimental adsorption data. The results show that adsorbent capacity increases with pressure, showing a maximum of 99.486mgOil/gγ-alumina at 25MPa. In addition, the concentration of anti-oxidant shows a tendency to increase during the curse of supercritical adsorption and with increasing system pressure. Fractions rich in anti-oxidants could be obtained at adsorption column outlet, showing a 2.0 fold enriching by 20MPa and a 6.5 fold enriching by 25MPa approximately, corroborating to assert this methodology as feasible to concentrate anti-oxidants from buriti oil. The supercritical adsorption of buriti oil fat soluble compounds in γ-alumina using carbon dioxide as solvent may be applied as an alternative method for the enriching of anti-oxidants. [Copyright &y& Elsevier]

Abstract: Brazil nut is one of the most important species from Amazon region with thousands of tons exported each year. With high content of oil, Brazil nut can be used for different applications. In this work the phase equilibrium of Brazil nut oil in supercritical carbon dioxide were measured, by static method, at pressures between 15 and 30MPa and temperatures of 323.15 and 343.15K. The experimental data were correlated using the Peng–Robinson and the Soave–Redlich–Kwong EOS with four different mixing rules: the van der Waals mixing rule for two binary interaction parameters, the Panagiotopoulos–Reid, Stryjek–Vera and Adachi–Sugie for three binary interaction parameters. For all isotherms studied the solubility of Brazil nut oil in the gaseous phase and that of carbon dioxide in the liquid phase increased, as the system pressure increases. For all mixing rules the Peng–Robinson and Soave–Redlich–Kwong EOS described very well the pseudo-binary system Brazil nut oil/carbon dioxide phase equilibrium data. [Copyright &y& Elsevier]