Optimization of soda cooking for cellulose production from sugarcane bagasse

Sugarcane bagasse, an agricultural residue, is a fibrous material containing cellulose as its main component, produced in large quantities worldwide. The aim of this work was to investigate the production of unbleached cellulose pulp from sugarcane bagasse using the soda cooking process with sodium hydroxide as the alkaline reagent. The cooking conditions were investigated with dosages of sodium hydroxide from 20% to 25%, temperatures from 150°C to 170°C, and cooking time from 75 to 105 min. The response surface methodology was used to study the effect of pulping variables on observed parameters. The results indicated that the optimal cooking conditions achieved the highest yield of 46.4% w/w and the lowest kappa number of 20.6 at a sodium hydroxide dosage of 23%, a temperature of 155°C, and a cooking time of 93 min. Further analysis of paper produced from the investigated pulp, refined at varying revolutions (0 to 3000 rpm), revealed that optimal strength properties were achieved at a refining level of 31°SR, equivalent to 2500 rpm. At this refining level, handsheets with a basis weight of 85 gsm exhibited a tensile strength of 2 kN/m, a burst strength of 2.7 kgf/cm², and a ring crush strength of 6.9 kgf. These findings confirm that the mechanical properties of the refined pulp meet the strength requirements of commercially recycled kraft paper, demonstrating its suitability for similar applications.