Development of a process raman probe of wood pulp as a continuous gauge of the physical and mechanical properties of end-use product: spectroscopy and chemometrics

加拿大北方漂白针叶木硫酸盐（NBSK）市场纸浆代表了纤维强度、长度、细度和均匀性的全球基准。为了保持在世界市场上的领先地位，加拿大纸浆工业必须不断开发和部署工艺技术，以提高纸浆成分的质量控制，特别是参考那些控制工艺参数和关键产品性能的内在纤维特性，如抗拉强度、柔软度和吸收性。例如，纤维素的结晶度和化学成分的分布，如木质素、半纤维素和己烯醛酸（HexA），决定了纸浆的可消化性和可漂白性，而在制浆过程中纤维变形的程度影响了在纸浆形成过程中纤维在网络中的强度和柔软度。这些参数和其他参数已被证明是制造效率，能源利用，环境性能和产品价值的重要决定因素，然而，除了木质素，没有一个可以很容易地及时测量过程控制。目前的提案要求开发一种新的拉曼系统和系统的化学计量方法，以便在恶劣的制造条件下对湿纸浆进行快速光谱数据采集和确定的光谱化学分析。该仪器系统将新型后向散射拉曼探针与复杂的化学计量学数据处理策略相结合，采用小波变换和模板引导遗传算法（TOGA）特征选择与多元分类，从原始拉曼光谱中提取最大的分析信息。将光谱化学观察与纤维参数的常规表征（如卷曲度、粗糙度、面积、周长和CSF）以及最终用途的纸张特性（包括爆裂、拉伸、撕裂、平滑、压缩、刚度、TEA和拉伸指数）相关联的研究项目，将产生一个全面的拉曼测量，用于即时测定纸浆质量和在线预测纸张外观、强度、柔软度和吸收性。

Canadian northern bleached softwood kraft (NBSK) market pulps represent the worldwide benchmark for fibre strength, length, fineness, and uniformity. To maintain this premier position in the world marketplace, the Canadian pulp industry must continuously develop and deploy process technologies that sharpen the quality control of pulp composition, particularly with reference to those intrinsic fibre characteristics that govern process parameters and key product properties, such as tensile strength, softness and absorbency. For example, the degree of cellulose crystallinity and distribution of chemical constituents, such as lignin, hemicullose, and hexenuronic acid (HexA), determine pulp digestibility and bleachability, while the degree of fibre deformation incurred during pulping process affects how the fibre delivers strength and softness in a network during sheet formation. These and other parameters have been shown to be important determinants of manufacturing efficiency, energy utilization, environmental performance and product value, however, aside from lignin, none can be easily measured in a timely manner for process control. The present proposal calls for the development of a novel Raman system, and systematic chemometric approach that will allow for rapid spectral data acquisition and definitive spectrochemical analysis of wet pulp under harsh manufacturing conditions. The instrument system will combine a novel backscattering Raman probe with a sophisticated chemometrics data-processing strategy, employing wavelet transform and template-guided genetic-algorithm (TOGA) feature selection with multivariate classification to extract maximum analytical information from raw Raman spectra. A program of research correlating spectrochemical observations with conventional characterization of fibre parameters, such as, curl, coarseness, area, perimeter and CSF, and end-use sheet properties, including burst, stretch, tear, smoothness, compression, stiffness, TEA and tensile indices, will give rise to a comprehensive Raman gauge for the instantaneous determination of pulp quality and the online prediction of paper appearance, strength, softness and absorbency.