Biorrefinería de materiales lignocelulósicos. "Eucalyptus globulus"

Ante un panorama mundial acuciante en cuanto a escasez de materias primas, energía y fenómenos relacionados con la no biosostenibilidad, efecto invernadero y problemas sociológicos relacionados con el mundo agrario, forestal y rural, la biomasa lignocelulósica, y en particular la de elevada capacidad de producción, se revela como una fuente de materias primas ubicua y sostenible, cada vez más necesaria. Las tres fracciones química principales constituyentes del material lignocelulósico: celulosa, hemicelulosa y lignina, son en teoría, susceptibles de separación en lo que llamamos un esquema de fraccionamiento integral o Biorrefinería. Estos constituyentes por si solos o sus derivados permiten obtener productos de mayor valor añadido y en multitud de campos con un esquema similar al de la refinería del petróleo. De la celulosa pueden derivar polímeros celulósicos, como los que utilizamos diariamente con el uso del papel, y de otro tipo. Además es susceptible de hidrolizarse hasta sus monómeros constituyentes para obtener medios fermentables para producción de etanol, biocarburante para transporte. De las hemicelulosas y sus azúcares monoméricos derivados (pentosas) pueden también derivarse medios fermentables, pero en este caso y dada la mayor variedad de monómeros y oligómeros constituyentes, las posibilidades de obtención de diversos productos químicos se amplían en un amplio espectro. Pueden obtenerse productos para cosmética, farmacia, productos para alimentación animal y humana (principalmente relacionados con alimentos dietéticos y funcionales), algunos tan conocidos como el xilitol, el ácido acético, el furfural y productos poliméricos de síntesis (resinas furánicas) de interesantes propiedades dado su carácter biodegradable en contraste con los plásticos derivados del petróleo. De la fracción polifenólica o lignina, existe el uso tradicional como combustible que se aplica en el sector de la pasta celulósica, el papel y que supone una valorización energética de la fracción residual. Sin embargo, cobran cada vez más auge las posibilidades de uso en el sector de materiales (tableros), derivados de esteroles con aplicaciones en farmacia o alimentación funcional, antioxidantes, materiales poliméricos y aditivos de betunes y asfaltos.________________________________________Faced with a global outlook urgent as regards shortage of raw materials, energy and phenomenon related with no biosustainability, greenhouse effect and sociological problems related with the world agricultural, forestry and rural development, lignocellulosic biomass, and particularly that of high capacity of production , emerges as a source of raw materials ubiquitous and sustainable, increasingly necessary. The three main fractions chemical constituent of lignocellulosic material: cellulose, hemicellulose and lignin, are in theory, capable of separation in that we call a integral fractionation scheme or Biorefinery. These constituents on their own or their derivatives allow obtaining products with higher added value and in many fields with a scheme similar to oil refining. Cellulose can be derived cellulose polymers, as those used daily with the use of paper, and otherwise. Moreover it capable of hydrolyze itself to its constituent monomers for to obtain fermentable media to produce ethanol, a biofuel for transport. Of hemicelluloses and their derived monomeric sugars (pentoses) can also derive fermentable media, but in this case and given the greater variety of monomers and oligomers constituents, the possibility of obtaining different chemicals are covered in a broad spectrum. Products are available for cosmetics, pharmaceuticals, food products for human and animal (mainly related to dietary and functional food), some so called xylitol, acetic acid, furfural and synthetic polymer products (furan resin) with interesting properties given its biodegradability in contrast to petroleum plastic. Fraction of phenolic or lignin, there is a traditional use as a fuel applies in the sector of cellulose pulp, paper and that suppose a energy value of the residual fraction. However, becoming increasingly the possibility of use in the sector use of materials (boards), derived from sterols with pharmaceutical applications or functional foods, antioxidants, polymeric materials and additives of bitumen and asphalt

Optimization the soda-AQ process for cellulose pulp production and energy content of black liquor from L. leucocephala K360

A commercial variety of Leucaena leucocephala K360 was used for pulp production and papermaking employing the soda-anthraquinone process. Also, the chemical and energy contents of the resultant black liquors were determined to simultaneously optimize: pulp and paper production and energy generation. A process temperature of (185 °C), an operating time of (120 min) and an active alkali concentration of (21%) provided sheets of paper with good strength (tensile index of 12.12 N m/g, burst index of 0.38 kPa m2/g, tear index of 1.29 mN m2/g and a Kappa number of 20.5) and black liquor with a greater calorific value (14.1 MJ/kg) than that obtained with higher active alkali concentrations. However, reducing the active alkali concentration to a level in the low operation range led to less marked degradation of cellulose and allowed paper sheets with good properties to be obtained and energy to be optimally produced from the black liquor

Search for optimum conditions of wheat straw hemicelluloses cold alkaline extraction process

A method for the selective extraction of hemicellulose from wheat straw involving cold alkaline extraction and subsequent separation by precipitation with ethanol is proposed. Wheat straw affords selective separation of the hemicellulose fraction from the cellulose and lignin fractions with the proposed method. The hemicellulose yield was optimized by using a 2n factor design to examine the influence of temperatures (temperature was designed between 20 and 40 ◦C), operation times (operation time was designed between 30 and 60 min) and alkali concentrations (alkali concentration was designed between 80 and 120 g L−1). These conditions allowed 56.1% of all hemicellulose initially present in the raw material, and 59.1% of the lignin, to be extracted. Subsequent separation of hemicellulose in the liquid phase from the cold alkaline extraction by precipitation with ethanol provided a fraction containing 39.4% of all hemicellulose (45.2% hemicellulose in extract/total extract) and only 12% of all lignin in the raw material.The authors are grateful for the FPU grant from the Spanish Ministry of Education. Also they thank to Spanish Ministry of Economy and Competitiveness (former Ministry of Science and Innovation) contracts. The authors acknowledge financial support for this investigation has been provided by CDTI (CENIT-E-CDTI-BioSos-CEN-2009-1040) and supported by Ministry of Economy and Competitiveness, "Local Investment fund for employment". Government of Spain, Junta de Andalucia, CICYT-FEDER (Science and Technology Inter Ministerial Commission, Spanish Government - European Regional Development Fund), project number AGL2009-13113 and the business group ACCIONA INFRAESTRUCTURAS, S.A

Biorefinery process for production of paper and oligomers from "Leucaena leucocephala K360" with or without prior autohydrolysis

Lignocellulosic material from Leucaena leucocephala was subjected to a two-stage fractionation process to obtain a valorized effluent containing hemicellulose derivatives and a solid phase for producing cellulose pulp by conventional soda-anthraquinone delignification. This solid phase allows the production of cellulose pulp, under less rigorous conditions from NaOH-AQ process (177 °C, 21%, 120 min) than without pretreatment delignification (185 °C, 25%, 150 min) and better or similar properties in the paper sheets obtained (yield 27.6 and 34.0%, brightness 39.3 and 31.6% ISO, tensile index 7.8 and 10.5 N m/g, burst index 0.43 and 0.29 MPa m2/kg with and without previous autohydrolysis) have be found. Also, the first autohydrolysis stage allows up to 46.6% of the initial hemicellulose in the raw material to be extracted as xylooligomers, xylose and furfural into the liquid phase

Variations in Production and Oligomers Content Obtained Under Hydrothermal Treatment Among Five Fast-Growing Species

In order to identify fast growing species utilizable for olygomer and monomer production, five fast growing species (Paulownia fortunei, Chamaecytisus proliferus, Arundo donax, Leucaena.diversifolia and Sesbania grandiflora) were tested. Concurrently, the biomass productivity of these species was also tested on a field scale. The biomass productivity of the selected species studied ranges from 0.36 to 21.30 t ha �1 (o.d.b.) under Mediterranean conditions for the year 1 sprouts. In addition, the hydrothermal treatment results show that the selected species could be employed as alternative raw material for the production of oligomers, leading to a high concentration of oligomers (9.4-23.4 g/L -1 at 190ºC

Cellulosic pulp from "Leucaena diversifolia" by soda–ethanol pulping process

A selection of the best wood raw materials for cellulose pulp and papermaking from five varieties of the Leucaena has been made (Leucaena diversifolia, Leucaena collinsii and three varieties of Leucaena leucocephala) with growth periods of one, two and three years. In accordance with biomass production and the features of the raw materials and cellulose pulp obtained, L. diversifolia in its second year of growth was selected as the most suitable material for pulp and papermaking. Pulping of L. diversifolia by soda–ethanol was studied using an experimental design in order to investigate the effects of cooking variables: temperature, time, soda concentration, ethanol concentration and wash-disintegrate temperature on the chemical composition of the obtained pulps (yield, kappa number, viscosity, solubles substances, lignin, holocellulose and α-cellulose contents) and the physico-chemical characteristics of paper sheets (tensile index). The results were evaluated using the response surface methodology. The optimum pulping conditions were established for this lignocellulosic material, using the model predictions. The pulp obtained at these conditions has suitable chemical (pulp) and physical (paper sheets) characteristics: yield (46.5%), 1%NaOH solubles (3.04%), hot water solubles (0.63%), ethanol–benzene extractives (0.44%), holocellulose contents (96.7%), α-cellulose contents (75.8%), lignin contents (0.85%), viscosity (1367) kappa number (15.2) and tensile index (19.2 kN m/kg)

Furfural production from "Eucalyptus globulus" : optimizing by using neural fuzzy models

Samples of Eucalyptus globulus were subjected to isothermal autohydrolysis (temperature: 220–250 °C and isothermal residence time 0–60 min). The effect of the R0 factor on the sugar yield and composition of both liquid and solid phases obtained after the treatments has been studied. The furfural concentration and composition has been determined. A central composite experimental design, in conjunction with the neural fuzzy model, was used to the furfural content maximization under isothermal autohydrolysis. A varied range, involving two independent variables at three different levels, was established for each process variable (viz. temperature and autohydrolysis time). The obtained models reproduced the experimental results of the dependent variables with errors below 6%. Under optimum experimental conditions, the yield of furfural (4.4 g/100 g dry raw material) could be obtained at 60 min and 220 °C)

Chemical and energetic characterization of species with a high‐biomass production : fractionation of their components

In this work, we determined the properties of cellulose pulp and paper from six different lignocellulosic materials [Eucalyptus globulus, Arundo donax, Leucaena diversifolia, Paulownia fortunei, sunflower stalks and Chamaecytisus proliferus (tagasaste)], as well as the calorific value and chemical composition of their autohydrolysis liquor, with a view to assessing their potential for the obtainment of energy, sugars and other chemical products. An integral fractionation method based on autohydrolysis and organosolv delignification was used for this purpose. Leucaena diversifolia; P. fortunei; a Paulownia “trihybrid” consisting of elongata, tormentosa and fortunei varieties; sunflower stalks; and C. proliferus exhibited holocellulose, glucan, xylan and acetyl group contents similar to, or higher than, those of E. globulus, A. donax and various other lignocellulosic materials. The amounts of oligomers extracted from C. proliferus, P. fortunei, L. diversifolia and sunflower stalks at the highest temperatures studied exceeded those provided by eucalyptus. Sequential autohydroysis and organosolv delignification of L. diversifolia and C. proliferus provided cellulose pulp with an acceptable kappa number and paper sheets with good strength-related properties. Paulownia fortunei was the most interesting raw material among those tested; in fact, it provided ethanol pulp with a lignin content of 3.7 –15.3% and a kappa number of 40.5–74.1 after autohydrolysis at 190 ºC, and paper with a tensile index of 17.0–28.9 kN m/kg. These properties are similar to those of pulp and paper from eucalyptus wood. In addition, P. fortunei exhibited the highest calorific value among the studied materials (4683.8 cal/g).The authors gratefully acknowledge funding of their Project CTQ2006-10329/PPQ by ENCE, S.A. (San Juan del Puerto factory, Huelva, Spain) and CICYT-FEDER (Science and Technology Inter-Ministry Commission, Spanish Government - European Regional Development Fund), and additional funding within the framework of the Ramon y Cajal and Juan de la Cierva programmes (Spain's Ministry of Education and Science)

Integral valorization of "Leucaena diversifolia" by hydrothermal and pulp processing

Wood from the leguminous tree, Leucaena diversifolia, was subjected to hydrothermal treatment (autohydrolysis) at 160–180 °C for 0–30 min followed by ethanol–soda–anthraquinone delignification. The liquid phase contained 18.65 g of sugars per liter, and the solid phase had a gross heating value of 19.083 MJ/kg, but could also be used as a source of cellulose pulp for the production of paper with tear, burst, and tensile indexes of 2.4 N m2/kg, 2.6 MPa m2/kg and 40.7 kN m/kg, respectively. L. diversifolia lends itself readily to valorization for energy production, and also to integral, fractional exploitation by autohydrolysis and ethanol–soda–anthraquinone delignification, which can additionally bring environmental benefits to cropping zones

Energetic characterization of lignocellulosic biomass from Southwest Spain

Different lignocellulosic biomass sources were characterized energetically along a study period of two years in Huelva (southwestern region in Spain) for energy production. Then, the different kinds of lignocellulosic biomass obtained from these sources were evaluated and classified according to use, such as fuel for electric power generation in the area. The groupings of the average moisture content values and average gross heating values (over dry basis) of the samples analyzed were made based on the type of material, and for larger groups (with a significant dispersion of the gross heating values), the average values were estimated in subgroups or “characteristic groups.” A six-cluster scheme allowed us to classify the different groups of materials. The average gross heating values of the six different clusters (raw materials) showed significant similarities. It was observed that softwood and related materials typically have values in the region of 20.0 MJ/kg, and hardwood, such as that from Eucalyptus globulus, yields about 18.0 MJ/kg, whereas other deciduous plants (and their residues) give lower values.The authors are grateful for the FPU grant from the Spanish Ministry of Education. Also, they extend their thanks to the Spanish Ministry of Science and Innovation by the "Ramon y Cajal" contract and by the "Juan de la Cierva" contract. The authors acknowledge Spanish financial support from CICYT-FEDER (Science and Technology Inter Ministerial Commission, Spanish Government - European Regional Development Fund), project number AGL 2009-13113 and the business group ENCE, S. A. (San Juan del Puerto factory, Huelva, Spain) for providing the samples