M.J. Feria

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 m(2)/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.

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.

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.

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 Nm/g, burst index of 0.38 kPa m(2)/g, tear index of 1.29 mN m(2)/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.