Milanesio J.,UniversitedeToulouse |
Hegel P.,Planta Piloto de Ingenieria Quimica |
Medina-Gonzalez Y.,UniversitedeToulouse |
Camy S.,UniversitedeToulouse |
Journal of Chemical Technology and Biotechnology | Year: 2013
BACKGROUND: Microorganisms have often been considered for the production of oils and fats as an alternative to agricultural and animal resources. Extraction experiments were performed using a strain of the yeast Yarrowia lipolytica (Y. lipolytica), a high-lipid-content yeast. Three different methods were tested: Soxhlet extraction, accelerated solvent extraction (ASE) and supercritical carbon dioxide (SCCO2) extraction using ethanol as a co-solvent. Also, high pressure solubility measurements in the systems 'CO2 + yeast oil' and 'CO2 + ethanol + yeast oil' were carried out. RESULTS: The solubility experiments determined that, at the conditions of the supercritical extractor (40 °C and 20 MPa), a maximum concentration of 10 mg of yeast oil per g of solvent can be expected in pure CO2. 10% w/w of ethanol in the solvent mixture increased this value to almost 15 mg of yeast oil per g of solvent. Different pretreatments were necessary to obtain satisfactory yields in the extraction experiments. The Soxhlet and the ASE method were not able to complete the lipid extraction. The 'SCCO2 + ethanol' extraction curves revealed the influence of the different pretreatments on the extraction mechanism. CONCLUSION: Evaluating the effectiveness of a given pretreatment, ASE reduced the amount of material and solvent used compared with Soxhlet. In all three cases, the best total extraction performance was obtained for the ethanol-macerated yeast (EtM). Addition of ethanol to the solvent mixture enhanced the oil solubility. Oil can be extracted from Y. lipolytica in two different steps: a non-selective ethanol extraction followed by TAG-selective SCCO2 purification. © 2012 Society of Chemical Industry.
Brugnoni L.I.,Planta Piloto de Ingenieria Quimica |
Pezzutti A.,National University of the South |
Gonzalez M.T.,National University of the South
International Journal of Food Engineering | Year: 2013
The effects on microbiological parameters of minimally pasteurized cloudy apple juice concentrate obtained in a pilot scale from two apple varieties, and their changes with storage time and temperature were investigated. The juice obtained from Red Delicious apples showed an adequate biological stability for import and export market for storage at-8.5 and-20°C during a period of three months. The preservation of samples at-20 and-8.5°C limited to acceptable values the growth of molds and yeasts during the first two months in the case of juice obtained from Granny Smith apples. Neither lactic acid nor thermo acidophilic bacteria were isolated from the samples in all storage conditions. No noticeable differences in pH and soluble solids content were observed among storage times and temperatures. Turbidity increased slightly with storage time. Viscosity decreased substantially during storage at 2°C. Color was stable for all storage conditions evaluated.
Diez A.S.,National University of the South |
Alvarez M.,National University of the South |
Volpe M.A.,Planta Piloto de Ingenieria Quimica
Journal of the Brazilian Chemical Society | Year: 2015
Mesoporous silicate (MCM-41) materials, modified with CuII, FeIII or AlIII were prepared by a hydrothermal method and were characterized by nitrogen adsorption at 77 K, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), temperature programmed reduction (TPR), adsorption of pyridine as monitored by Fourier transform infrared spectroscopy (FTIR) and n-butylamine titration. The degree of ordering of the mesoporous material was decreased by the presence of Cu, Fe, or Al. The added Fe or Cu gave rise to new acidic and oxidation-reduction sites, while Al resulted in new acidic sites. The hydrothermal stabilities of selected samples were studied as a function of temperature and pH. All the samples were stable in acidic and neutral media at temperatures from 303 to 363 K. Adsorption of phenol on MCM-41 at 303 K was strongly influenced by the pH and by the modification with Cu, Fe, or Al. Phenol adsorption was particularly strong at the Al-modified material at pH 3, apparently due to the acidic character of phenol. © 2015 Sociedade Brasileira de Química.
Gutierrez V.,Planta Piloto de Ingenieria Quimica |
Dennehy M.,National University of the South |
Diez A.,National University of the South |
Volpe M.A.,Planta Piloto de Ingenieria Quimica
Applied Catalysis A: General | Year: 2012
A series of Cu/MCM-48 catalysts is studied for the liquid phase hydrogenation of crotonaldehyde. Copper is incorporated in MCM-48 following a classical hydrothermal synthesis or by wet impregnation of the MCM-48 precursor (before eliminating the directing agent) with Cu(AcAc)2. The copper loading is in the 2-20 wt% range. Characterization results from TPR and XRD indicate that copper crystals supported on MCM-48 surface coexist with copper incorporated in the MCM-48 walls. The presence of Cu+ in MCM-48 is concluded from characterization with FTIR of adsorbed CO. This species would be the responsible for the relatively high selectivity of Cu/MCM-48. These catalysts show approximately 50% of selectivity against 7% of Cu/SiO2 (both values measured at 10% of conversion). © 2012 Elsevier B.V. All rights reserved.
Tonelli S.M.,Planta Piloto de Ingenieria Quimica |
D'alessandro A.A.,Planta Piloto de Ingenieria Quimica |
Gigola C.E.,Planta Piloto de Ingenieria Quimica
5th CCPS Latin American Conference on Process Safety 2013, LACPS 2013 | Year: 2013
A review of the most serious accidents in the chemical industry shows that most of them were due to the propagation and escalation of consequences or "domino effect". Nevertheless, the phenomena involved and the propagation mechanisms are not fully understood. In this work we present a survey of the most recent methods and models used to analyze the domino effect. In a comprehensive discussion of the available literature, the papers are classified according to their objective. Works dealing with case studies and historical databases contribute to the understanding of particular propagation mechanisms and their frequency of occurrence. Papers focused on the revision of available models for the quantitative estimation of damage caused by physical effects introduce rigorous ways to calculate the effects of fires and explosions. Finally, we paid special attention to the methodologies used for QRA with domino alternatives. Although there are several different techniques to estimate the domino effect, there is a consensus that its inclusion in the models increases the calculated risk. © (2013) by AIChE.