Lignocellulosic Biomass Fractionation and Depolymerization with Sub/Supercritical Fluids

开发新的环境友好技术对于从大量木质纤维素生物质（下文称为生物质）产生增值产品至关重要。亚/超临界条件下的流体是农业副产品（滞销农作物秸秆）和食品工业副产品（马铃薯皮）生物质加工的通用溶剂。加压液体（PL，例如亚临界水）和超临界流体（SCF），例如超临界水和超临界二氧化碳（SC-CO2）提供了一种绿色加工平台，以使用分馏技术获得新的增值产品。最近，使用PL/SCF作为反应介质引起了人们的注意解聚。报告表明，通过优化反应温度和压力，可以控制水解，以获得针对特定应用的目标增值化合物。然而，所涉及的反应机理需要进一步研究，以及它们的活化能和体积。 迄今为止，申请人的研究计划集中于使用亚临界水和SC-CO2来确定所选糖和酚类化合物的溶解度，生物活性物质如酚类化合物、碳水化合物、青蒿素等的提取，以及在SC-CO2介质中和在热处理辅助的高压下的反应，以及化合物在新溶剂混合物中的相平衡的建模。因此，未来的工作将继续建立在这一专业知识的进一步贡献，新的组合处理PL/SCF媒体的发展。 该提案的主要目标是扩展PL中增值化合物溶解度行为的基础知识，并确定热力学变量和传输性质如何影响分馏，反应，颗粒形成和PL/SCF介质中这些过程的组合，以进一步开发新的绿色技术，以获得生物质的增值产品，该产品可在食品和非食品中具有许多用途。食品工业应用。在拟议的研究计划中，将通过实验测量溶解度等热力学性质。平衡研究将允许选择分馏和反应过程的最佳压力和温度。对于反应过程，将使用马铃薯皮和稻草，其中将在用PL/SCF处理之前和之后测定它们的纤维素、半纤维素和木质素的含量。新的工艺组合将进行实验研究。分馏后，进一步解聚将进行评估，以获得各种增值化合物。半纤维素中发现的增值化合物可以首先被去除，然后残余物可以通过特定反应或富集纤维素的残余物转化为增值化合物。然后，将通过新工艺开发获得纳米纤维素纤维/晶体。 依靠创新加工技术开发增值化合物的总体目标将通过实验室规模的概念验证基础研究来实现。一旦新工艺建立，将研究涉及谷类作物不同生物量的应用。有价值的信息的影响，工艺参数将获得一个批量和半连续系统，未来的目标是实现它的连续系统。PL/SCF技术的使用最大限度地减少或消除了有机溶剂和催化剂的使用，从而最大限度地减少了对环境的影响，满足了具有环境和健康意识的消费者日益增长的需求，并通过探索大量的生物质来促进加拿大的生物经济。

Development of new environmentally friendly technologies is crucial to generate value-added products from vast lignocellulosic biomass, herein after referred to as biomass. Fluids under sub/supercritical conditions are versatile solvents for biomass processing of agricultural by-products (unmarketable crop straw) and food industry by-products (potato peel). Pressurized liquid (PL, e.g. subcritical water) and supercritical fluids (SCF), such as supercritical water and supercritical carbon dioxide (SC-CO2) provide a green processing platform to obtain new value-added products using fractionation techniques. Recently, the use of PL/SCF as reaction media has attracted attention for depolymerization. Reports have shown that by optimizing the reaction temperature and pressure, hydrolysis can be controlled to achieve targeted value-added compounds for specific applications. However, the reaction mechanisms involved need to be further investigated as well as their activation energy and volume. The applicant's research program to date has focused on the use of subcritical water and SC-CO2 to determine solubility of selected sugars and phenolics, extraction of bioactives, such as phenolics, carbohydrates, artemisinin, etc, as well as reactions in SC-CO2 media and under high pressure assisted by thermal processing, and modeling of phase equilibria of compounds in new solvent mixtures. Future work would therefore continue to build on this expertise by further contributions to novel combined processing development in PL/SCF media. The main objectives of this proposal are to expand fundamental knowledge on solubility behavior of value-added compounds in PL, and to determine how thermodynamic variables and transport properties influence fractionation, reaction, particle formation and the combination of these processes in PL/SCF media to develop further new green technologies to obtain value-added products of biomass that can have a number of uses in food and non-food industrial applications. In the proposed research program, thermodynamic properties, such as solubility will be measured experimentally. Equilibrium studies will allow the selection of optimum pressure and temperature for fractionation and reaction processes. For the reaction process, potato peel and straw will be used where their contents of cellulose, hemicellulose and lignin will be determined before and after treatments with PL/SCF. Novel combination of processes will be experimentally investigated. After fractionation, further depolymerization will be assessed to obtain a diverse range of value-added compounds. Value-added compounds found in hemicellulose can be first removed and then the residues can be converted to value-added compounds through specific reactions or enriching the residue in cellulose. Then, nano-cellulose fiber/crystal will be obtained by novel process development. The overall goal of developing value-added compounds relying on innovative processing technologies will be accomplished through fundamental research at laboratory scale for proof-of-concept. Once the novel process is established, applications involving diverse biomasses of cereal crops will be investigated. Valuable information on the effect of process parameters will be obtained for a batch and semi-continuous system with a future goal to implement it on a continuous system. The use of PL/SCF technology minimizes or eliminates the use of organic solvents and catalysts, thus minimizing environmental impact and meeting the growing demands of environment- and health-conscious consumers as well as boosting Canada’s bioeconomy with the exploration of vast biomass available.