The effect of soda cooking variables on pulp production from Kenaf stalk

Considering the chemical behavior of the pulping process under variable conditions, especially in nonwoods species, is important as it can help us to develop the pulping models to reach the pulps with desired properties. In the present research, the soda pulping under different conditions was investigated to produce whole stalk kenaf pulp as the most common pulping processes for non-woody species. The cooking conditions were included temperatures (160 and 165 °C), active alkali levels (18, 23, and 28 %) and cooking duration (90, 105, 120, 135, 150, 165, and 180 min). Results indicated that pulp yield was in the range of 47 to 69 % and the kappa number was in the range of 29 to 67. The statistical analysis showed that cooking durations, alkali levels, and cooking temperatures had significantly independent effects on pulp yield and kappa number, although their interactions on pulp yield and kappa number were not significant. Based on the present results, the fastest and the slowest changing rates of kappa number and pulp yield were related to the pulping condition of 23% active alkali in 160 C and 18% active alkali in 165 C, respectively.