INTEGRATED PROCESSES FOR PURIFYING A CELLULOSIC MATERIAL

摘要

A process for converting a starting material to a purified pulp material, comprising removing lignin from a starting material to form a wet pulp comprising at least 5 wt.% water, extracting hemicellulose from the wet pulp with an extractant, and separating the extracted hemicellulose from the extraction mixture to form a cellulosic product comprising less hemicellulose than the wet pulp. The extractant comprises a cellulose solvent and a co-solvent. The cellulosic product advantageously retains its cellulosic fiber morphology. The process involves separating and recovering hemicellulose and separating and recycling various process streams employed in the process.