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Soda-anthraquinone (soda-AQ) pulping of barley straw was used to obtain cellulosic pulps for papermaking purposes. The identified parameters, or variables to be optimized, were operating time, anthraquinone concentration, and PFI refiner revolutions, and the influence of these operating variables on pulp properties was studied. A polynomial model that reproduced the experimental results with errors less than 6% was developed. Operating variables were found (46 min of processing time, 0.4 wt.% of anthraquinone concentration, and 3000 rpm of PFI revolution) that yielded competitive pulp properties (82 °SR beating grade number, 870 mL/g of viscosity, Kappa number of 13, 77 Nm/g of tensile index, and 30% ISO brightness) at reasonable chemical and energy costs. On the other hand, this study highlights the usefulness of this polynomial model as a method to minimize the use of anthraquinone in these pulping processes and to be able to predict what the pulp properties will be. For comparison purposes, new operating conditions were found, and the pulp properties still remain at a very good level for this cereal straw. [ABSTRACT FROM AUTHOR]

Abstract: The influence of temperature (150–190°C), time (0–20min), liquid/solid ratio (6–8) and sulfuric acid concentration (0.1–0.5%), on the hydrolysis of palm empty fruit bunches (EFBs) was studied and the liquid and solid fractions were analyzed. Polynomial models were found to reproduce the experimental results with errors less than 15% in most of the cases (except for xylose concentration). Operating conditions of 190°C for 15min at a liquid/solid ratio of 6 and a sulfuric acid concentration of 0.1% resulted in the production of 3.12, 4.0, 2.35 and 2.28g/L of glucose, xylose, arabinose and acetic acid, respectively, starting with 1000g of EFBs. The yield was 67.96%. Soda-anthraquinone, ethanol and ethanolamine pulping of the solid fraction provided pulps with brightness values (63.24%, 28.78%, 48.76%), but with poor resistance properties (6.57–8.54Nm/g for tensile index, 0.38–0.44kN/g for burst index and 0.96–1.02mNm2/g for tear index). Therefore it is advisable to use the pulps for speciality papers or for bioethanol-production. [Copyright &y& Elsevier]

Abstract: The main objective of this work is to evaluate the suitability of Hesperaloe funifera which is an alternative raw material, for pulping with soda–anthraquinone to produce pulp and paper. It was studied the influence of operational variables (temperature (155–185°C), cooking time (20–60min) and soda concentration (5–15%), with a constant addition of 1% of anthraquinone and a liquid/solid ratio of 8, in soda–anthraquinone cooking of H. funifera on pulps and paper sheets properties obtained. Finally, the cooking liquors were acidified to separate solid fractions that were subjected to pyrolysis and gasification in order to obtain synthesis and fuel gases. H. funifera contains little lignin and abundant α-cellulose; this, together with the morphological characteristics of its fibers, makes it a potentially highly useful papermaking raw material. [Copyright &y& Elsevier]

Abstract: The main objective of this work is to evaluate the suitability of rice straw and soda–anthraquinone (soda–AQ) pulping process to produce pulp and paper. To reach this aim, it was used a central composite factorial design to study the influence of operational variables (temperature (155–185°C), cooking time (30–90min), soda concentration (10–20%), anthraquinone concentration (0–1%) and liquid/solid ratio (6–8)), in soda–anthraquinone cooking of rice straw on pulps and paper sheets properties obtained. Based on the yield values obtained, nearly one half of the raw material can be efficiently converted into cellulose pulp and paper sheets. Also, the Kappa number/viscosity ratio of the pulp facilitates its efficient bleaching. Finally, based on the values for above-described physical properties, the pulp can be used to obtain paper or board and recycled paper (as % virgin fibre). In Spain are produced annually 757,000t of rice straw. If we considered an average yield process of 45%, it would be possible to obtain 340,000 tons of pulp. These tons would be absorbed by the market taking into account the necessities in cellulosic pulp consumption. [Copyright &y& Elsevier]