Five pilot-scale steam explosion pretreatments of sugarcane bagasse followed by alkaline delignification were explored. The solubilised lignin was precipitated with 98% sulphuric acid. Most of the pentosan (82.6%), and the acetyl group fractions were solubilised during pretreatment, while 90.2% of cellulose and 87.0% lignin were recovered in the solid fraction. Approximately 91% of the lignin and 72.5% of the pentosans contained in the steam-exploded solids were solubilised by delignification, resulting in a pulp with almost 90% of cellulose. The acidification of the black liquors allowed recovery of 48.3% of the lignin contained in the raw material. Around 14% of lignin, 22% of cellulose and 26% of pentosans were lost during the process. In order to increase material recovery, major changes, such as introduction of efficient condensers and the reduction in the number of washing steps, should be done in the process setup.
Highlights
► The mass balance showed effective for quantify of the components of bagasse. ► Eighty-two percent of the pentosan and 100% of the acetyl group were solubilised during pretreatment. ► Ninty-one percent of the lignin was solubilised by delignification process. ► Most of 90% of the cellulose was recovered in the delignification process. ► Fourteen percent of lignin, 22% of cellulose and 26% of pentosans were lost in the global process.
