Rheological Characterization of Dilute Acid Pretreated Softwood
Rheological Characterization of Dilute Acid Pretreated Softwood
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DOI：
10.1002/bit.23020
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发表时间：
2011-05-01
影响因子：
3.8
通讯作者：
Liden, Gunnar
中科院分区：
文献类型：
--
作者：
Wiman, Magnus;Palmqvist, Benny;Liden, Gunnar
从木质纤维素生物质中大规模生产生物乙醇在酶解步骤中需要高固体负荷。然而，由于纤维的性质，预处理木质纤维素的浆液是复杂的流体，特别是在高浓度的水不溶性固体（WIS）下。处理运输问题和开发有效的全面工艺的先决条件是对预处理木质纤维素的流动特性有一个基本的了解。考虑到WIS浓度、粒径分布（PSD）和酶解程度的影响，本研究对稀酸预处理云杉进行了全面的流变学表征。经预处理的云杉浆的流变性与WIS浓度有很大关系。存储模量（G′（LVR））和屈服应力与体积分数和WIS含量呈幂律关系。预处理材料的铣削导致屈服应力和粘度显著提高，可能是由于PSD更窄，这表明最粗纤维网络的强度在很大程度上决定了这些材料的流变性。在酶解过程中，屈服应力和粘度急剧下降，部分原因是WIS含量的减少，但也可能是由于纤维性质（如化学成分）的变化。Biotechnol。Bioeng。2011;108: 1031 - 1041。(C) 2010 Wiley期刊公司
Large-scale bioethanol production from lignocellulosic biomass will require high solids loading in the enzymatic hydrolysis step. However, slurries of pretreated lignocelluloses are complex fluids due to the fibrous nature, especially at high concentrations of water insoluble solids (WIS). A prerequisite for dealing with transport issues and for developing efficient full-scale processes is a fundamental understanding of the flow properties of pretreated lignocellulose. A comprehensive rheological characterization of dilute acid pretreated spruce has been carried out in this study, accounting for the effects of WIS concentration, particle size distribution (PSD), and the degree of enzymatic hydrolysis. The rheology of pretreated spruce slurries was found to be strongly dependent on the WIS concentration. The storage modulus (G'(LVR)) and yield stress showed typical power-law dependencies on volume fraction and WIS content. Milling of the pretreated material resulted in significantly higher yield stress and viscosity, likely due to narrower PSD, which suggests that the strength of the network of the coarsest fibers determines the rheology of these materials to a large extent. During enzymatic hydrolysis, yield stress and viscosity decreased dramatically, partly due to decreasing WIS content, but possibly also due to changes in fiber properties such as the chemical composition. Biotechnol. Bioeng. 2011;108: 1031-1041. (C) 2010 Wiley Periodicals, Inc.