Extraction of Lignin from Kraft Cooking Liquor by Ultrafiltration

摘要: Lignin is a potential biofuel which can be extracted from kraft cooking liquor. also prove valuable as speciality chemical. By extracting lignin economical revenue gained by pulp mills, well technical benefits such easier delignification and bleaching. The subject of this work was the extraction liquor using ceramic ultrafiltration membranes. Experiments have been performed in both laboratory, at temperatures below 100°C, mill between 90°C 145°C. In order to operate membranes high new methods ensure safe reliable operation were developed. Membranes with cut-offs 5,000 Da 15,000 used experimental studies. laboratory investigation average flux during concentration 90% volume reduction 55 l/m² h 110 cut-off membranes, respectively. At same time retention 60% 30%. purity respect total dry solids content increased 30% membrane Da. Reaching higher purities alone proved difficult, it therefore suggested that diafiltration or acid precipitation on retentate achieve purities. It shown technically feasible above normal boiling point when treating highly alkaline solutions. The lower than investigation. It found temperature dependent, decreasing 55% 145°C (at 400 kPa transmembrane pressure). Fouling cleaning investigated trials. A successful method based rinsing permeate followed developed trials could operated for up 70 hours without fouling becoming too severe capacity restored after chemical cleaning.