Separation of Cellulose on a Pilot Scale

What is pulp separation and why is pulp digester used?

The purpose of the cooking is to separate and expose the fibres, remove lignin and extractives, and reduce the variability of the incoming wood material.

Separation of cellulose in pilot plant:

The pilot plant for cooking and separating cellulose is flexible. RISE has developed efficient methods and equipment for simulation of all commercial cooking methods. RISE has extensive experience of different coking systems and is continuously working on improvements in both sulphate and sulphite cooking.

Chip and lye samples from the mill are used to simulate the existing digester in a laboratory environment under controlled conditions. The pilot digester can also be used as reactors in biorefinery investigations.

• Improved yield
• Designing cleaner processes for the future
• Improving separation and purification efficiency
• Digitalisation and simulations
• Characterisation of raw materials and product variations
• Efficient separation of cellulose when cooking wood chips

Separating cellulose from wood chips of different types and sizes can now be done more efficiently. The chips can be cooked simultaneously in the same digester, under identical process conditions, yet kept separate to ensure optimal quality and control.

Flexible process conditions for cellulose extraction

The process offers full flexibility by adjusting key parameters such as:

• Time: Adjusting the cooking time for optimal separation.
• Temperature: Precise control of temperature for best cellulose yield.
• Cooking liquid displacement: Optimised liquid volume management for efficient extraction.
• Cooking liquid levels: Adjustment of chemical concentrations for different types of wood chips.
• Cooking methods: Possibility to simulate both batch and continuous cooking to achieve the desired results.
• Deduction and addition of cooking liquids during the process

During the cooking process, both removal and addition of cooking liquids can be done, providing further opportunities for process optimisation and higher precision in cellulose separation.

Capacity for large-scale testing

The system allows the cooking of up to 100 kg of wood chips, making it possible to perform extensive tests on:

• Different types of wood (e.g. hardwood and softwood).
• Mixed chip sizes.
• Different process conditions for optimal separation and energy efficiency.
• Advantages of the cellulose separation technology
• Efficient separation of cellulose from mixed chip batches.
• Optimised process parameters such as temperature and time.
• Simulation of both small and large-scale cooking processes (batch and continuous cooking).
• Customisation of cooking fluid properties for specific needs.

It is also possible to investigate:

Wood variations such as species, tree part (root-top), age (juvenile-mature), chemical composition, dimensions, wood rot, storage rot, dry content, size distribution, impurities, density, lightness.

Studies in wood handling: Purification such as wood and wood stock, debarking, chipping, chip storage, chip sieving, bark content, wood content in bark fraction, dry-wood density. Studies on wood chips such as lignin content, hemicellulose.

Real-time Chip Impregnation Pilot

Impregnation studies are of interest for all chemical pulp processes, whether the end product is paper pulp or dissolving pulp. It is especially important to have properly impregnated chips for pulp mills seeking to increase production or encountering issues related to impregnation.