Integration of bioproducts and pulp production in a BCTMP mill

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Bleached chemi-thermomechanical pulp (BCTMP) has been increasingly used in papers as a cost-effective way to improve product performance. Canada produces over 70% of the world's market BCTMP and most of them are exported to Europe and Asia. However, the Canadian BCTMP producers are now facing strong competition from low-cost producers in the world and need to develop new technologies to increase their revenue and/or reduce production cost in order to stay competitive. Pre-extraction of hemicelluloses for bioproducts may provide additional revenue to a BCTMP mill. The extracted flows from hardwood BCTMP mills can be rich in hemicelluloses, thereofre, providing opportunities to pre-extract and convert these extracts into value-added bioproducts before making pulp. The chemical pre-treatment stage of a BCTMP process can easily be served as the pre-extraction stage without major capital investment. Earlier studies by the author et al. have shown that acid pre-extraction before the normal BCTMP process can reduce production cost by significantly reducing the refining energy. Pulp bulk and surface properties are not affected but brightness and strength are reduced. Therefore, work is required to investigate ways to maximize the extraction efficiency while minimizing the loss of brightness and strength during the pre-extraction stage. The extraction efficiency and impact on pulp properties with various chemicals in pre-extraction have not been studied for a BCTMP process. There are also challenges such as how to concentrate/separate/purify the hemicelluloses from the dilute stream. The present program addresses these needs and will aim to develop and implement new technologies/bioproducts for the Canadian BCTMP companies, therefore, increasing their competitiveness by providing new revenues and reducing production cost. What acquired from this study could also be applied to the thermomechanical pulp mills that are facing a significant downturn of the demand for paper advertising.