Two-step delignification of peracetic acid and alkali from sugar cane bagasse

Abstract

Sugar cane bagasse was delignified in a two-step process with peracetic acid and alkali. Peracetic acid pre-treatment with concentration of 25% based on oven-dry fiber at 60 min, with a liquor to wood (L/W) ratio of 9:1 and a temperature of 50 °C improved the second stage delignification, compared with soda pulping. The second stage was carried out at three levels of temperatures, times, and 20% sodium hydroxide based on oven-dry fiber. Soda pulping at 165 °C, 120 min, 20% sodium hydroxide based on oven-dry fiber, and L/W 10:1 was selected to compare with two-step delignification. The two-step delignification reduces the severity of pulping conditions, including temperature and pressure, and subsequent imposes less risks compared with the soda pulping at 165 °C. The advantages of this method are high delignification and reduction of kappa number with respect to lower temperature and pressure compared with soda pulping. The total time in two-step was increased from soda pulping. Two optimum conditions for alkali step were obtained at 120 °C and 140 °C and 90 min for pretreated bagasse pulping, and similar properties were achieved with soda pulping at 165 °C and 120 min. The yield of fibers, Kappa number, and data analysis using Duncan method were measured and recorded.