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Abstract: The influence of the hydrothermal treatment conditions of rice straw (temperature – 150–190°C , time – 0–20min after reaching the operation temperature – and liquid/solid ratio – 6–8), on the composition of liquid and solid fractions was studied. Polynomial models were found for to reproduce the experimental results with errors less than 6%. Operating to 190°C, 15min and 9 liquid/solid ratio was obtained high values of glucose (1.92g/L), xylose (3.97g/L), arabinose (0.99g/L) and acetic acid (1.96g/L), what allows to save capital when not operating with the maximum time and/or liquid/solid ratio; yield in the solid fraction is 88.1% and lignin content 24.43%. If what it is required to obtain good values of yield (96.46%) and lignin content, is necessary to operate to 150°C, obtaining lower concentrations glucose (1.11%), xylose (2.78%), arabinose (0.56%) and acetic acid (0.39%). Ethanolamine pulping of solid fraction of hydrothermal treatment provides pulp with higher or similar properties to those obtained of pulping rice straw with ethanolamine or soda. [Copyright &y& Elsevier]

Abstract: The influence of temperature in the hydrothermal treatment of sunflower stalks on the composition of the liquid fraction obtained was examined. The remaining solid fraction was subjected to ethanol pulping in order to obtain pulp that was used to produce paper sheets. The pulp was characterized in terms of yield, kappa index, viscosity, and cellulose, hemicellulose and lignin contents; and the paper sheets in terms of breaking length, stretch, burst index and tear index. Hydrothermal treatment of the raw material at 190°C provided a liquid phase with maximal hemicellulose-derived oligomers and monosaccharide (glucose, xylose and arabinose) contents (26.9 and 4.2g/L, respectively). Pulping the solid fraction obtained by hydrothermal treatment at 180°C, with 70% ethanol at a liquid/solid ratio of 8:1 at 170°C for 120min provided pulp with properties on a par with those of soda pulp from the sunflower stalks, namely: 36.3% yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin and 551ml/g viscosity. Also, paper sheets obtained from the ethanol pulp were similar in breaking length (3.8km), stretch (1.23%), burst index (1.15kN/g) and tear index (2.04mNm2/g) to those provided by soda pulp. [Copyright &y& Elsevier]

Abstract: To determine the overall efficiency of processes designed to convert lignocellulosic polysaccharides to ethanol, it is first necessary to determine the composition of the lignocellulosic substrates. Three standard methods routinely referenced in the literature for this purpose are monoethanolamine, trifluoroacetic acid and concentrated sulphuric acid-based methods. However, in the course of our studies, the suitability of these standard methods for analysis of wastepaper and wheat straw came into question. This paper details our investigations in this area, together with recommendations for appropriate modifications to one of the standard methods for reproducible and representative lignocellulosic compositional analysis of waste paper and cereal straw. [Copyright &y& Elsevier]