Bleaching of Cellulose

Purpose

The bleaching process can be customized and optimized depending on the requirements of the final paper or board. Some types of paper require a gentler bleach to preserve the strength of the fibers and to avoid over-fading, while others require a more aggressive bleaching to achieve the desired lightness and whiteness.

By understanding the bleaching process and implementing the necessary adjustments and optimizations, the paper and pulp industry can produce high-quality products with the desired properties and durability. This not only helps to meet customer requirements and expectations, but also to reduce environmental impact and promote sustainable production methods.

Performing sampling and analysis before and after the whitening process is essential to assess the efficiency and quality of the whitening as well as to compare with the customer's existing process. Here is a more detailed description of the process:

• Sampling phase: Before starting the bleaching process, samples are taken from the raw material (usually chips or pulp after boiling).
• The whitening process: After the samples are taken, the whitening process is carried out according to the planned bleaching steps. 
• Sampling step after each bleaching step: After each bleaching step, samples from the bleaching process are taken to assess the effect of the specific bleaching step. 
• Boiling and bleaching experiments in relevant equipment: After the whitening process is complete, the corresponding boiling and bleaching experiments are carried out in a relevant equipment. 
• Comparison with the customer's line: The analyzed samples before and after the whitening are compared with samples from the customer's line to assess similarities and differences. 
• Comparison with Customer's Line: The analyzed samples before and after bleaching are compared with samples from the customer's line to assess similarities and differences. This provides a deeper understanding of how the bleaching process affects the material and enables identification of any deviations or areas for improvement that may need to be addressed.

Variations in conditions such as pulp consistency, pressure, temperature, and different bleaching chemicals enable a versatile bleaching process that can be tailored to different types of pulp and desired outcomes. Here is a more detailed description of the variables that can be adjusted and the different bleaching equipment used:

• Pulp Consistency
• Pressure
• Temperature
• Bleaching Chemicals: All commercially used bleaching chemicals can be used in the bleaching process to achieve different results and properties in the final product. This may include chlorine bleaching, oxygen bleaching, peroxide bleaching, and ozone bleaching.
• Bleaching Equipment: RISE uses various bleaching equipment such as Quantum mixers, autoclaves, and conventional water baths to perform bleaching experiments under controlled conditions. 
• Sample Size: The sample size can vary from small amounts (0.5 kg) for laboratory experiments to larger batches (5-10 kg) to simulate production conditions and optimize the process for industrial scale.

RISE can therefore carry out bleaching of various types of pulps, including chemical pulps (wood pulp and dissolving cellulose), pre-hydrolyzed sulfate cellulose for dissolving, mechanical pulps, dissolving, and plant fibers. By applying the same conditions in the laboratory as in the factory environment, RISE ensures that the results obtained are relevant and transferable to the production process

Methods and Expertise

RISE has the capability to use all common bleaching chemicals in its pilot equipment for bleaching. These chemicals include:

• Chlorine dioxide
• Hydrogen peroxide
• Peracetic acid
• Hypochlorite
• Oxygen
• Ozone

Expertise:

In bleaching and pulp processing, RISE has a long history of conducting research and providing expertise. Our team of researchers and engineers possess broad and deep knowledge of various bleaching methods and pulp processes, including chlorine bleaching, oxygen bleaching, and other advanced techniques used to produce quality paper and pulp.

Deliveries

RISE offers a report that includes data in Excel format along with relevant images and diagrams. It is carefully compiled using standard methods for the analyses performed.

If a more detailed report is required, RISE has the capacity to provide a comprehensive scientific report based on the results and background information supplied by the customer, available upon request and quotation.