PERSONAL DE APOYO
COTABARREN Natalia Soledad
congresos y reuniones científicas
Título:
Sustainable technologies for oil-based second generation biorefineries
Autor/es:
N. COTABARREN; P. HEGEL; S. PEREDA
Lugar:
Campinas
Reunión:
Workshop; Workshop on Supercritical Fluids and Energy (SFE'13); 2013
Institución organizadora:
PETROBRAS Research & Development Center. Federal University of Santa Catarina. Federal University of Rio Grande do Norte. Federal University of Ceara. University of Campinas. Brazil.
Resumen:
A biorefinery is, by definition, the integrated production of food, fodder, chemicals, materials, goods, and fuels by means of bio- or physicochemical processing of biomass. In that sense, human bodies are a good example of biomass processing to recover energy and chemicals to produce materials; however, the atomic efficiency of modern societies is quite low. Even worse, as can be seen in big cities, the richer the population is, more residues produces. Losses in the feed chain have not yet been seriously examined. In summary, the second-generation biorefineries not only should process non edible biomass, but also it should push forward the gain of edible biomass resources. In that sense, new technologies for biomass recycling and residues processing are needed to enhance the bio-economy matrix. It is important to look at food processing industrial centers and urban residues. For example, the great increase of worldwide production of soybean and sunflower oil, impacted not only in the oil market but also in the oil refining by-products (phospholipids sludge and distillates of the deodorizer), which prices are rapidly changing. Even though these residues contain high-added value products, their cost are decreasing, becoming sometimes a waste with disposal-associated problems. Furthermore, sludge processing to recover oil or phospholipids is complex. Because of its high viscosity and poor flow properties (sticky behavior), its processing needs large volumes of solvent, and consequently, it is expensive. An alternative sustainable technology is the direct alcoholysis of phospholipids and vegetable oil (triglycerides) occluded in the wet gum using supercritical ethanol to produce fatty acids ethyl esters (FAEE). Oil gums contain approximately 45% water, 25% oil and 30% phospholipids. Therefore, the conventional alkaline process is a non-viable alternative to produce fatty esters from SOGs. By contrast, the transesterification process by supercritical alcoholysis is an interesting option for this unconventional and low-cost feedstock[1]. On the other hand, with respect to high added value chemicals, in biodiesel processing plants acylglycerols can be economically produced. Acylglycerols are common food emulsifiers and surface active agents in many industrial cleaning products. Commercial MG is obtained via an alcoholysis pathway in which either fatty acids or a fat are reacted with an excess of glycerol. The reaction products contain mainly mono-, di-, tri-glycerides (MG, DG, TG, respectively) and glycerol, but depending on the glycerol/fat ratio the MG composition fluctuates between 40 and 60% of MG [2]. A further refined MG up to around 90 wt% purity, also called high mono, is conventionally obtained by short path distillation of the reaction products at ca. 473 K and 0.01 mbar or less [2]. This process is expensive and recovers only part of the produced MGs. Moreover, MG concentration higher than 96 wt. % cannot be achieved by vacuum distillation because of interesterification reactions causes degradation of MG towards glycerol and free fatty acids. Peter et al. [3] proposed an interesting alternative to obtain 99 wt.% purity of MG from the acylglycerides mixture by means of supercritical fluid extraction using mixtures of carbon dioxide and propane as extraction solvents. An alternative pathway to produce MG, instead of transesterification, is the glycerolysis of fatty acid methyl esters. In this case the separation problem downstream of the reactor completely changes. Purification of MG from a mixture of biodiesel can be carried out with pure CO2 as a green solvent[4]. CO2 presents complete solubility with fatty esters in a wide range of temperature and pressure, and exhibits partial miscibility with acylglycerols (both in liquid and supercritical state).This alternative appears as a promising process with direct application in the biodiesel and food industry. Nowadays strong regulations are set on oil-based biorefineries to use non edible vegetable oils. In that respect, the urban residual oils and fats are an interesting source of fatty acids for biodiesel production. The commercial process to convert used cooking oil (UCO) to used cooking oil methyl esters (UCOME) is a pretreatment of the oil with high content of fatty acids. The acid oil can be reacted with glycerol to produce a mixture of acylglycerols, which are fed in a transesterification plant, after its purification by vacuum distillation[5]. Due to the immiscibility of the reactants, the reaction rate is very low. In order to enhance the miscibility it is carried out at temperatures above 200ºC, but the long residence time causes thermal degradation of the raw materials, which end up in highly contaminating effluents. A phase equilibrium engineering of this reaction requires thermodynamics models able to predict the multiphase behavior. GCA-EoS is a group contribution with association model that has shown good traits to predict phase behavior of these types of mixtures. In this presentation, sustainable technologies for residues processing and vegetable oil recycling will be discussed. Moreover, also a high pressure technology for high purity monoglycerides recovery will be presented. Integration of the discussed technologies may contribute to pave the way towards oil-based second generation biorefinery development. Finally, trends in the field of oil recycling and oil based fuels other than biodiesel will be discussed.[1] G. Soto, A. Velez, P. Hegel, G. Mabe, S. Pereda, Journal of Supercritical Fluids 79 (2013) 62[2] Fischer, W. DGF-Symposium in Germany. 1998.[3] Peter, S., Czech, B., Ender, U., Weidner, E. US Patent 5 434 280 (1995)[4] S G. Soto, P. Hegel, S. Pereda, III Iberoamercian Conference on Supercritical Fluids, Cartagena de India, Brazil, 2013[5] P. Felizardo, J. Machado, D. Vergueiro, M. J. N. Correia, J. Pereira Gomes, J. Moura Bordado, Fuel Processing Technology 92 (2011) 1225