Enhancing dissolving pulp production and co-product value

溶解纸浆用于制造用于服装、香烟滤嘴、医药等产品的纤维素衍生物。溶解纸浆由95%的纤维素组成，因此在制浆过程中必须去除半纤维素和木质素。尽管纤维素净化是一个密集的过程，但硫酸盐纸浆厂转换为生产溶解纸浆具有变革性，因为该厂采用了真正的生物精炼方法，有可能从纤维素、半纤维素、木质素和可提取的生物质成分中产生价值。将常规硫酸盐纸浆机改造为生产可溶纸浆时，关键的工艺改进是木屑的预水解，这有助于去除半纤维素，而随后的硫酸盐法制浆主要是为了去除木质素。堡垒特种纤维素(FSC)是加拿大使用预水解硫酸盐(PHK)纸浆原料生产可溶纸浆的前沿企业。然而，PHK工艺存在瓶颈，因为它需要更长的蒸煮时间和上游硫酸盐法制浆额外的消化池容量。因此，提高半纤维素脱除效率的方法可以提高溶解纸浆厂的整体生产率。在预水解过程中，木材在高温的酸性条件下进行处理以溶解半纤维素，因此随后将酸性预水解浆过渡到高碱性硫酸盐工艺也带来了挑战。除了这些挑战，PHK工艺每年生产约40,000公吨半纤维素糖。因此，这种半纤维素流的有价化对于工厂的运转和创造额外收入以实现生物精炼方法至关重要。建议的具体目标可概括为：1.用酶处理木屑，以加强预水解过程中随后的半纤维素的去除；2.在PHK生产过程中整合绿液预处理，以减少pH控制问题，提高纤维素产量；3.通过发酵将预水解过程中产生的半纤维素作价为“生物喷射式”和“插入式”燃料。

Dissolving pulp is used for manufacturing cellulose derivatives that are used in products such as clothing, cigarette filters, pharmaceuticals, etc. Dissolving pulp is composed of >95% cellulose, thus the hemicellulose and lignin must be removed during the pulping process.Although cellulose purification is an intensive process, the conversion of a Kraft pulp mill to produce dissolving pulp is transformative, as the mill adapts a true biorefinery approach with the potential to generate value from the cellulose, hemicellulose, lignin and extractive biomass components. The critical process modification when converting a conventional Kraft mill to produce dissolving pulp is the prehydrolysis of the wood chips which helps to facilitate the removal of hemicellulose, while subsequent kraft pulping is mostly aimed at removing the lignin. Fortress Specialty Cellulose (FSC) is at the forefront of Canadian efforts to produce dissolving pulp using a pre-hydrolysis Kraft (PHK) pulp feedstock. However, the PHK process presents bottlenecks as it requires extended cooking times and additional digester capacity upstream of kraft pulping. Therefore, methods that can boost hemicellulose removal can increase the overall production rate of a dissolving pulp mill. During prehydrolysis, wood is**subjected to treatment under acidic conditions at high temperatures to dissolve the hemicellulose, thus the subsequent transitioning of the acidic prehydrolyzed pulp to the highly alkaline kraft process also presents challenges. As well as these challenges, the PHK process annually produces approximately 40,000 metric tonnes of hemicellulosic sugars. Therefore, valorization of this hemicellulose stream is crucial to the functioning of the mill and creating additional revenues to realize a biorefinery approach. The specific objectives of the proposal can be summarized as follows: 1. To treat wood chips with enzymes to enhance the subsequent removal of hemicellulose during the prehydrolysis process; 2. To integrate green liquor pretreatment during PHK production to reduce pH control issues and enhance cellulose yields and 3.To valorize the hemicellulose produced during pre-hydrolysis through fermentation to "bio-jet" and "drop-in" fuel.