Patent ID: 8709203
Filing Date: 2014-04-29
Classification: B01D,C01B,C08B,D21C

Abstract:
1. A process for producing NCC comprising: acid hydrolysis of bleached wood pulp; recovering NCC from said hydrolysis; recovering an aqueous waste liquor from said hydrolysis, said aqueous waste liquor containing acid and sugars derived from said hydrolysis of bleached wood pulp, said sugars comprising a monomeric sugar fraction and an oligomeric sugar fraction; separating said aqueous waste liquor into discrete fractions of aqueous acid, monomeric sugars and oligomeric sugars with a pair of discrete membranes; said separating comprising: concentrating said aqueous permeate containing said inorganic acid and residual sugars from said nanomembrane, without precipitation of sugars or fouling during said concentrating, to an aqueous acid solution having a concentration of acid of 50% to 70%, by weight for acid hydrolysis of bleached wood pulp in NCC production, and recycling said aqueous acid solution as an acid supply to said acid hydrolysis for NCC production.