INVESTIGADORES
AREA Maria Cristina
congresos y reuniones científicas
Título:
Optimization of the Soda-ethanol delignification in the biorefinery of rice husk
Autor/es:
DAGNINO, P.E.; FELISSIA, F. E.; CHAMORRO, M.; AREA M. C.
Lugar:
Concepción
Reunión:
Congreso; 3er Congreso Iberoamericano sobre Biorrefinerías (CIAB), 4to Congreso Latinoamericano sobre Biorrefinerías, y 2do Simposio Internacional sobre Materiales Lignocelulósicos; 2015
Institución organizadora:
CIADEB-RIADICYP-PROVALOR-BIOREN- Centro de Biotecnología UdeC- Unidad de Desarrollo Tecnológico (UDT)- VTT
Resumen:
Lignocellulosicmaterials are an interesting alternative to obtain products with high addedvalue, such as bioethanol, food and cosmetics additives, and adhesives, amongmany others. Rice hulls (RHs) is an abundant residue in the Argentine Northeastregion (provinces of Corrientes, Entre Rios, Santa Fe, Formosa and Chaco). Riceproduction in Argentina in 2012/13 reached 1,397,242 tons, of which about 20%was RHs. RHs is composed of 48.7% carbohydrates (34.1% cellulose and 14.6% hemicelluloses),17.2% and 1.8% of insoluble and soluble lignin acid respectively, 15% ofinorganic components, and others, so the application of the biorefineryconcept, i.e. the separation and valorization of its individual components, isof high interest. Delignification of RHs pretreated with acid (previouslyoptimized process) was carried out using an Organosolv soda-ethanol process.This treatment is advantageous since the reaction is faster, it uses smalleramount of soda than the conventional soda process, and the ethanol can berecovered and reused. A Central Composite Experiment Design of two variableswith three replicas of the center point was used. Soda concentrations between 9and 17g per liter, and ethanol concentrations between 46 and 60% wereevaluated. The liquor was placed in a reactor of AISI 316 stainless steel of180ml, with a closing screw gauge. It was heated in a heat resistant siliconebath to 160°C. The reaction time was 60min, and it was necessary aroundadditional 25min to reach 160°C. The mixture was then cooled in a cold waterbath and filtered through a 100 mesh sieve. The solid was washed repeatedly toremove the remaining solution. The concentration of residual lignin (NREL process/TP-510-42618)in the pretreated solid was measured as response variable and delignification relativeto initial lignin was calculated on this basis. The results were analyzed usingmultivariate analysis of variance (ANOVA). Statgraphics statistical software wasused, with a level of significance of 95%. The adjusted model explained the 92%of the variability. Both variables showed significant effect (p ≤ 0.05) on theresidual lignin in the treated solid. The percentage of delignification rangedfrom 73% in the treatment with 13g/l NaOH and 46% EtOH; to 90% in the treatmentwith 13g/l NaOH and 53% EtOH. The optimal response corresponded to 13 g/l NaOH (centralpoint) and 50% EtOH (-0.8 as coded variable), with a theoretical value ofresidual lignin in the solid of 1.61% (equivalent to 92% of delignification).In conclusion, the sequence acid / soda-ethanol allowed hemicellulosesextraction in the first stage and lignin extraction in the second stage. Theresidual solid was composed almost entirely of cellulose with approximately 25%of inorganic components, which will be separated in future studies, to fullyimplement the biorefinery concept.