A conceptual process design for CNC production is shown in Figure . The process consists of five stages: grinding, hydrolysis, purification, post-treatment, and acid recycling. Hydrolysis, purification and acid recycling are modelled using Aspen Plus to simulate the energy flows and the overall mass flows. In the grinding stage, a knife mill is employed to grind the raw material -bleached softwood Kraft pulp from 1000 to 500 𝜇𝑚.