Investigation on the Potencial of Colza Stem in Paper Production

This study was concentrated to investigate the influence of chemical treatment time and temperature on production of chemi-mechanical pulp from Colza stem. Three treatment times (15, 30 and 45 minutes) and two treatment temperatures (125 and 145 °C) were investigated. Chemical charge as 4% NaOH and 8% Na2SO3 as well as L/W equal to 7/1 was kept constant and high pressure cooking vessel was used. Accepted pulp yield varied between 53.8% (severe pulping) and 63% (mild pulping) and the total yield for these pulping conditions was measured between 57.6% and 68.9%. The residual lignin in low yield pulp was measured as 19% and higher yield pulp was 20.4%. Holocellulose content of pulps varied between 72.5%- 74% and freeness was between 520-590 ml CSF. Fiber quality analysis using Fiber Quality Analyzer (FQA) showed that average fiber length of pulps are between 0.54-0.65 mm, fine content is high and fiber coarseness is between 0.21-0.41 mg/m. Even though the pulp freeness was reduced from original value to about 300 mL CSF as pulps were refined in PFI mill applying 500 revolutions, but the fiber quality did not change. Measurement of fiber classification using Bauer-McNett procedure revealed similar results to FQA. Brightness was measured between 31.86- 43.38%, opacity above 99% and transparency between 4.86- 7.16%, which did not change as the pulps were refined. Strength properties of paper from these pulps before and after refining were also measured. The unrefined strength including tensile index, burst index and tear index were measured as 15.48- 26.13 N.m/g, lower than 1 kPa.m2/g and 2.91- 4.34mNm2/g respectively. These indices after treatment in PFI mill (500 revolutions) were raised to 19.74-35.19 N.m/g, 1.70 kPa.m2/g and 3.21- 4.68 mNm2/g respectively.