Implementation of biorefining technologies in Kraft mills: impact assessment and feasibility

牛皮纸工艺生产木浆，用于制造高质量的打印纸、纸巾和包装材料。在保持其传统核心产品制造的同时，它是部分转向生物精炼的有吸引力的候选者。森林生物炼油厂的前提是，木材中的一些有机成分是溶解在废液中的化学制浆步骤的副产品，可以用于比目前所做的现场焚烧更大的好处，以恢复其打浆价值；它们可以用作生产各种具有重大市场价值的产品的原料。然而，将硫酸盐厂转变为生物炼油厂将深刻地改变其可持续能源生产的能力。该项目建议开发一种方法和标准来评估加拿大硫酸盐纸浆厂生物精炼方案的技术经济可行性。从高集成度和高能效的硫酸盐厂这一基本案例出发，我们将应用最先进的模拟技术和系统工程工具来研究关键的生物精炼技术对过程的能量平衡和运行成本的影响。分别是木素沉淀法、半纤维素提取法和生物质气化法。将开发一种新的高级能效分析方法并将其应用于这项研究。它将单独和联合考虑影响能源消耗的因素：内部能源回收、使用蒸汽注入和混合、水系统关闭、热力和电力生产以及采用能源升级技术(热电联产、吸收热泵)。经济可行性将通过一种新的热经济分析方法进行评估。将确定生物精炼技术对工艺空气排放的影响。该项目的主要成果将是可用于审查拟议生物精炼概念的可行性的指导方针，指导对这些技术的投资，并帮助制定解决技术障碍的研究战略。将为纸浆厂的生物炼油厂制作和验证生物炼油厂单元操作的模型和独特的过程模拟软件。

The Kraft process produces wood pulp for the manufacture of high quality printing papers, tissue papers and packaging material. It is an attractive candidate for partial conversion to biorefinery while maintaining the manufacturing of its traditional core products. The premise of the forest biorefinery is that some of the organic constituents of the wood which are by-products of the chemical pulping step dissolved in the spent liquor may be used for greater advantage than being burnt on-site to recover their beating value as is currently done; they could be used as feedstock for the manufacture of a broad variety of products which have a significant market value. However, the conversion of a Kraft mill to a biorefinery will profoundly modify its capacity for sustainable energy production. This project proposes to develop a methodology and criteria to evaluate the techno-economic feasibility of biorefinery options for Canadian Kraft mills. Starting from the base-case of highly integrated and energy efficient Kraft mills, we will apply state-of-the-art simulation techniques and systems engineering tools to examine the effects of key biorefinery technologies on the energy balance and operating cost of the process. They are, lignin precipitation, hemicelluloses extraction and biomass gasification. A new methodology for advanced energy efficiency analysis will be developed and applied to the study. It will take into account the factors that affect energy consumption individually and in conjunction: internal energy recovery, use of steam injection and mixing, water systems closure, heat and power production and the incorporation of energy upgrading technologies (co- and tri-generation, absorption heat pumps). Economic viability will be assessed by a new thermo-economic analysis method. The impacts of biorefining technologies on the process air emissions will be determined. The major outcome of this project will be guidelines that can be applied to examine the feasibility of proposed biorefinery concepts, guide investments in these technologies and help develop research strategies that address technical impediments. Models of biorefinery unit operations and a unique process simulation software for pulp mill-based biorefineries will be produced and validated.