Enhancing dissolving pulp production and co-product value

溶解浆用于制造纤维素衍生物，这些纤维素衍生物用于服装、香烟过滤嘴、药品等产品。溶解浆由>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。虽然纤维素纯化是一个密集的过程，但将硫酸盐纸浆厂转化为生产溶解浆是一种变革，因为工厂采用真正的生物精炼方法，具有从纤维素、半纤维素、木质素和提取生物质组分产生价值的潜力。将传统硫酸盐法制浆厂改造为生产溶解浆时，关键的工艺改进是木片的预水解，这有助于促进半纤维素的去除，而随后的硫酸盐法制浆主要旨在去除木质素。Fortress Specialty Cellulose（FSC）是加拿大使用预水解硫酸盐（PHK）纸浆原料生产溶解纸浆的最前沿。然而，PHK工艺存在瓶颈，因为它需要延长蒸煮时间和硫酸盐法制浆上游的额外蒸煮器容量。因此，可以促进半纤维素去除的方法可以增加溶解纸浆厂的总生产率。在预水解期间，木材在高温下在酸性条件下经受处理以溶解半纤维素，因此随后将酸性预水解纸浆过渡到高碱性硫酸盐法工艺也提出了挑战。除了这些挑战外，PHK工艺每年生产约40，000公吨半纤维素糖。因此，这种半纤维素流的价格稳定对于工厂的运作和创造额外的收入以实现生物精炼方法至关重要。该提案的具体目标可以概括如下：1.在预水解过程中，用酶处理木片以增强随后的半纤维素去除; 2.在PHK生产过程中整合绿色液预处理，以减少pH控制问题并提高纤维素产率; 3.通过发酵使预水解过程中产生的半纤维素增值为“生物喷射”和“直接”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.