Use of butanol-water mixtures for making wheat straw pulp
ABSTRACT A central composite design was used to investigate the influence of the cooking conditions (time, temperature and butanol
concentration) for wheat straw with butanol-water mixtures on the properties of the pulp obtained (yield and holocellulose,
α-cellulose, lignin and ethanol-benzene extractives contents) and the pH of the resulting waste water. A second-order polynomial
model consisting of three independent process variables was found to accurately describe the organosolv pulping of wheat straw.
The equations derived predict the yield, the holocellulose, α-cellulose, lignin and ethanol-benzene extractives contents of
the pulp, and the pH of the waste water with multiple-R, R2, adjusted-R2 and Snedecor' F values of 0.99, 0.99, 0.99 and 310.33; 0.98, 0.97, 0.95 and 56.63; 0.91, 0.84, 0.74 and 9.14; 0.99, 0.98,
0.96 and 70.52; 0.97, 0.94, 0.92 and 40.42; and 0.98, 0.95, 0.93 and 49.33, respectively.
The process variables must be set at low values in order to ensure a high yield and pH. On the other hand, if a high holocellulose
content and low lignin and ethanol-benzene extractives contents are to be obtained, then the process variables must be set
at high values. Finally, obtaining pulp with a high α-cellulose content entails using a long cooking time and a high temperature,
as well as a low butanol concentration.
- SourceAvailable from: Alejandro Rodríguez[Show abstract] [Hide abstract]
ABSTRACT: This paper reports on the influence of independent variables in the pulping of olive wood trimmings [viz. cooking temperature (165–195 °C) and time (30–90 min), ethanolamine concentration (5–15%), soda concentration (2.5–7.5%) and liquid/solid ratio (4–6)], on the yield and kappa number of the pulps and breaking length, burst index and tear index of the resulting paper sheets.By using a central composite factorial design, equations that relate each dependent variable to the different independent variables were obtained that reproduced the experimental results for the dependent variables with errors less than 15%. These equations could be used to find the suitable operations conditions, so that operating with not too high values of operating variables (with the consequent minor costs of capital and of operation) pulps could be obtained by acceptable strength properties.Optimizing pulp yield, the kappa number and the strength properties of the resulting paper sheets entails using rather different conditions in each case.Obtaining acceptably strong paper sheets while saving on immobilized capital through the use of smaller facilities and less chemical reagents entails using a medium soda concentration and low values of all other independent variables. In this way, the yield is 22.2% lower, the kappa number 42.5% higher, and the breaking length, burst index and tear index 6.2, 29.1 and 29.6%, respectively, lower than their optimum values; in any case, the strength properties increase although the pulp was suitably refining.Biochemical Engineering Journal. 01/2008;
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ABSTRACT: The results of characterization for four different vine shoot varieties, grown using two different methods, revealed no significant differences in composition among vine varieties or between growing methods. The holocellulose content of vine shoots (67.14%) is lower than those of other non-wood raw materials (e.g. wheat straw, sunflower stalks, cotton stalks, etc.), but similar to those of pine and higher to those of olive trimmings. On the other hand, their lignin content (20.27%) is similar to those of eucalyptus and the non-wood raw materials. Also, their contents in cold-water, hot-water and 1% soda solubles, and ethanol–benzene extractables, are higher than for pine and eucalyptus.Soda, kraft, ethanol and ethylene–glycol pulping processes have low yields (29–47%) relative to the pulping processes applied to olive trimmings and wheat straw. Kraft pulp is that exhibiting the best properties, including a higher α-cellulose content (73.74%) than pulp from wheat straw or olive trimmings, but a higher lignin content (17.18%). Also, kraft pulp provides paper with the highest breaking length, burst index and tear index (viz. 1316m, 1.63kN/g and 1.59mNm2/g, respectively); these values, which are intermediate among those for olive trimmings, wheat straw and sunflower seeds, are low and can be substantially improved by appropriate refining of the pulp.Industrial Crops and Products - IND CROPS PRODUCTS. 01/2006; 23(2):122-130.
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ABSTRACT: In the present work, a novel approach to pretreat wheat straw pulping was investigated with ultrasound and xylanase to achieve maximum reduction in lignin content. Sequential xylanase pretreatment and alkaline pulping was found to reduce kappa number by 0.31 to 4.84 % compared with only alkaline pulping alone at different pulping conditions. Although Klason lignin of ultrasound-treated straw was found to be 7.37 % less compared with untreated straw, sequential ultrasound pretreatment and alkaline pulping could not show any significant reduction in kappa number compared with alkaline pulping alone. Also, sequential xylanase and ultrasound pretreatment could not show any significant reduction in kappa number. Total yield of the pulp was found to be less in ultrasound-assisted processing compared with both alkaline pulping alone and sequential xylanase pretreatment and alkaline pulping.Applied biochemistry and biotechnology 08/2012; 168(4):731-41. · 1.94 Impact Factor