Suchergebnisse

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).

A central composite factorial design was used in conjunction with the software ANFIS Edit MATLAB 6.5 to develop fuzzy neural model that reproduced the experimental results of the dependent variables with errors less than 6%. The model is therefore effective with a view to simulating the autohydrolysis process. In this study it was evaluated the potential of a species trihybrid Paulownia fortunei, tormentosa and elongata as an industrial crop in terms of its contents in holocellulose, lignin, xylo-oligomers, monomers and other glucan and its use for making cellulose pulp. It was optimized biomass autohydrolysis processes to obtain valuable liquid and solid phases that can be used to produce liquid fuels and cellulosic pulp. The process was modelled in order to optimize the extraction of xylo-oligomers and xylose in the liquid phase while preserving the integrity of cellulose fibres. ; The authors acknowledge financial support from the Grupo Empresarial ENCE, S.A. (San Juan delPuerto factory, Huelva, Spain) and VICIDEX EUROPA S.L., and the CICYT-FEDER (Science and Technology Inter Ministerial Commission, Spanish Government European Regional Development Fund), projects numbers CTQ2006-10329/PPQ and AGL2009-13113 for their support, and to the "Ramon y Cajal", "Juan de la Cierva" and FPU Programs of the Spanish Ministry of Science and Innovation.

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.

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.