Steam Explosion Pre-Treatment on Alkali-Oxygen Pulping of Bamboo, 2007 Engineering, Pulping & Environmental Conference

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A study was conducted on the morphology of the fibers and chemical composition of the 3-years-old bamboo-culm of Gigantochloa verticiliata, Thyrsostachys siamensis, Dendrocalamus latiflorus, and Bambusa arundinacea for pulping them by alkali-oxygen, alkali-sulfite and sulfate process to a target Kappa number less than 20. Alkali-oxygen pulping conditions were pretreatment with steam pressure varied at 17-25 kg/cm² for 5 minutes follow by soaking with 1% NaOH, liquor to wood ratio 10:1 at 90^oC for 10 minutes and cooking with 15% NaOH, liquor to wood ratio 4:1 with oxygen pressure at 7 kg/cm² at 105^oC for 90 minutes. Alkali-sulfite pulping conditions were chemical charge 40% on wood, Na₂SO₃:NaOH varied at 8-3:2-7, liquor to wood ratio 4:1, maximum temperature 165^oC, total time 3 hours. Sulfate pulping conditions are sulfidity 25%. Active alkali varied at 13-23% liquor to wood ratio 4:1, maximum temperature 165^oC, total time 3 hours. The optimum condition for alkali-oxygen process were pretreatment with steam pressure at 21 kg/cm² for 5 minutes follow by soaking with 1% NaOH, liquor to wood ratio 10:1 at 90^oC for 10 minutes and cooking with 15% NaOH, liquor to wood ratio 4:1 with oxygen pressure at 7 kg/cm² at 105^oC for 90 minutes, for alkali-sulfite process were chemical charge 40% on wood with Na₂SO₃:NaOH = 4-3:6-7, liquor to wood ratio 4:1, maximum temperature 165^oC, total time 3 hours, for sulfate process were sulfidity 25%, Active alkali 21%, liquor to wood ratio 4:1, maximum temperature 165^oC, total time 3 hours. Pulp produced and pulp properties from alkali-oxygen process were lower than alkali-sulfite and sulfate process, the pulp yield was not so high and strength properties near chemi-mechanical pulp for newsprint. Pulp produced from alkali–sulfite and sulfate process had good pulp yield and strength properties which are proper for wrapping paper and grocery bag paper and bleached pulp is fitting for printing and writing paper. Produced pulps from whole process were bleached by P-P, O-P-P and D-P-D-P method to find the optimum condition for bleaching. Bleaching by D-P-D-P method was suitable for pulp produced from whole processes because bleached pulp is whiter than by any other method.